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Summary Background Daunorubicin and cytarabine are used as standard induction chemotherapy for patients with acute myeloid leukaemia. CPX-351 is a dual-drug liposomal encapsulation of daunorubicin and cytarabine in a synergistic 1:5 molar ratio. Primary analysis of the phase 3 trial in adults aged 60–75 years with newly diagnosed high-risk or secondary acute myeloid leukaemia provided support for approval of CPX-351 by the US Food and Drug Administration and European Medicines Agency. We describe the prospectively planned final 5-year follow-up results. Methods This randomised, open-label, multicentre, phase 3 trial was done across 39 academic and regional cancer centres in the USA and Canada. Eligible patients were aged 60–75 years and had a pathological diagnosis of acute myeloid leukaemia according to WHO 2008 criteria, no previous induction therapy for acute myeloid leukaemia, and an Eastern Cooperative Oncology Group performance status of 0–2. Patients were randomly assigned 1:1 (stratified by age and acute myeloid leukaemia subtype) to receive up to two induction cycles of CPX-351 (100 units/m2 administered as a 90-min intravenous infusion on days 1, 3, and 5; on days 1 and 3 for the second induction) or standard chemotherapy (cytarabine 100 mg/m2 per day continuous intravenous infusion for 7 days plus intravenous daunorubicin 60 mg/m2 on days 1, 2, and 3 [7+3]; cytarabine for 5 days and daunorubicin on days 1 and 2 for the second induction [5+2]). Patients with complete remission or complete remission with incomplete neutrophil or platelet recovery could receive up to tw cycles of consolidation therapy with CPX-351 (65 units/m2 90-min infusion on days 1 and 3) or chemotherapy (5+2, same dosage as in the second induction cycle). The primary outcome was overall survival analysed in all randomly assigned patients. No additional adverse events were collected with long-term follow-up, except data for deaths. This trial is registered with ClinicalTrials.gov , NCT01696084 , and is complete. Findings Between Dec 20, 2012, and Nov 11, 2014, 309 patients with newly diagnosed high-risk or secondary acute myeloid leukaemia were enrolled and randomly assigned to receive CPX-351 (153 patients) or 7+3 (156 patients). At a median follow-up of 60·91 months (IQR 60·06–62·98) in the CPX-351 group and 59·93 months (59·73–60·50) in the 7+3 group, median overall survival was 9·33 months (95% CI 6·37–11·86) with CPX-351 and 5·95 months (4·99–7·75) with 7+3 (HR 0·70, 95% CI 0·55–0·91). 5-year overall survival was 18% (95% CI 12–25%) in the CPX-351 group and 8% (4–13%) in the 7+3 group. The most common cause of death in both groups was progressive leukaemia (70 [56%] of 124 deaths in the CPX-351 group and 74 [53%] of 140 deaths in the 7+3 group). Six (5%) of 124 deaths in the CPX-351 group and seven (5%) of 140 deaths in the 7+3 group were considered related to study treatment. Interpretation After 5 years of follow-up, the improved overall survival with CPX-351 versus 7+3 was maintained, which supports the previous evidence that CPX-351 can contribute to long-term remission and improved overall survival in patients aged 60–75 years with newly diagnosed high-risk or secondary acute myeloid leukaemia. Funding Jazz Pharmaceuticals.

CPX-351, a dual-drug liposomal encapsulation of daunorubicin/cytarabine in a synergistic 1:5 molar ratio, is approved for the treatment of adults with newly diagnosed, therapy-related acute myeloid leukemia (t-AML) or AML with myelodysplasia-related changes (AML-MRC). In a pivotal phase 3 study, patients aged 60 to 75 years with newly diagnosed, high-risk/secondary AML were randomized to receive CPX-351 or conventional 7+3 chemotherapy. In the primary endpoint analysis, CPX-351 demonstrated significantly prolonged median overall survival (OS) vs 7+3. These exploratory post hoc subgroup analyses evaluated the impact of achieving complete remission (CR) or CR with incomplete neutrophil or platelet recovery (CRi) with CPX-351 (73/153 [48%]) vs conventional 7+3 (52/56 [33%]) on outcomes. CPX-351 improved median OS vs 7+3 in patients who achieved CR or CRi (25.43 vs 10.41 months; hazard ratio = 0.49; 95% confidence interval, 0.31, 0.77). Improved median OS was seen across AML subtypes (t-AML, AML-MRC), age subgroups (60 to 69 vs 70 to 75 years), patients with prior hypomethylating agent exposure, and patients who did not undergo transplantation. Patients who achieved CR or CRi with CPX-351 also had a higher rate of transplantation, a longer median OS landmarked from the date of transplantation (not reached vs 11.65 months; hazard ratio = 0.43; 95% confidence interval, 0.21, 0.89), and a safety profile that was consistent with the known safety profile of 7+3. These results suggest deeper remissions may be achieved with CPX-351, leading to improved OS. This study was registered at www.clinicaltrials.gov as #NCT01696084.

Introduction: Intensive induction chemotherapy followed by post-remission consolidation and/or allogeneic hematopoietic transplantation has been a standard-of-care therapy for acute myeloid leukemia (AML) for decades. In recent years, a plethora of new agents have been approved for AML treatment, dramatically changing the AML treatment landscape.Areas covered: This review provides an overview of the current role of intensive chemotherapy in the changing AML treatment landscape. PubMed-indexed publications (through 2020) and abstracts presented at major national and international conferences were reviewed for inclusion.Expert opinion: While intensive chemotherapy is standard-of-care therapy for younger patients with AML, older patients were historically viewed as universally ineligible for intensive chemotherapy; however, several studies suggest many older patients benefit from intensive chemotherapy with a curative intent, and a more holistic approach to determining eligibility for intensive treatment is recommended. Intensive strategies have also been expanded to include novel chemotherapy designs and chemotherapy in combination with targeted agents for patients with certain disease characteristics, which may permit more personalized treatment decisions. Intensive chemotherapy continues to play a pivotal role for the management of many AML patients and can offer the best chance of long-term remission, especially when followed by transplantation.

Purpose: The Polo-like kinase 1 (PLK1) is a master regulator of mitosis and overexpressed in acute myeloid leukemia (AML). We conducted a phase Ib study of the PLK1 inhibitor, onvansertib, in combination with either low-dose cytarabine (LDAC) or decitabine in patients with relapsed or refractory (R/R) AML. Patients and Methods: Onvansertib was administered orally, in escalating doses, on days 1–5 in combination with either LDAC (20 mg/m2; days 1–10) or decitabine (20 mg/m2; days 1–5) in a 28-day cycle. The primary endpoint was to evaluate first-cycle dose-limiting toxicities and the MTD. Secondary and exploratory endpoints included safety, pharmacokinetics, antileukemic activity, and response biomarkers. Results: Forty patients were treated with onvansertib (12–90 mg/m2) in combination with LDAC (n = 17) or decitabine (n = 23). Onvansertib was well tolerated with most grades 3 and 4 adverse events related to myelosuppression. In the decitabine arm, the MTD was established at 60 mg/m2, and 5 (24%) of the 21 evaluable patients achieved complete remission with or without hematologic count recovery. Decrease in mutant circulating tumor DNA (ctDNA) during the first cycle of therapy was associated with clinical response. Engagement of the PLK1 target, TCTP, was measured in circulating blasts and was associated with greater decrease in bone marrow blasts. Conclusions: The onvansertib and decitabine combination was well tolerated and had antileukemic activity particularly in patients with target engagement and decreased mutant ctDNA following treatment. This combination will be further investigated in the ongoing phase II trial.

Purpose: Spleen tyrosine kinase (SYK) signaling is a proposed target in acute myeloid leukemia (AML). Sensitivity to SYK inhibition has been linked to HOXA9 and MEIS1 overexpression in preclinical studies. This trial evaluated the safety and efficacy of entospletinib, a selective inhibitor of SYK, in combination with chemotherapy in untreated AML. Patients and Methods: This was an international multicenter phase Ib/II study, entospletinib dose escalation (standard 3+3 design between 200 and 400 mg twice daily) + 7+3 (cytarabine + daunorubicin) in phase Ib and entospletinib dose expansion (400 mg twice daily) + 7+3 in phase II. Results: Fifty-three patients (n = 12, phase Ib and n = 41, phase II) with previously untreated de novo (n = 39) or secondary (n = 14) AML were enrolled (58% male; median age, 60 years) in this study. The composite complete response with entospletinib + 7+3 was 70%. Patients with baseline HOXA9 and MEIS1 expression higher than the median had improved overall survival compared with patients with below median HOXA9 and MEIS1 expression. Common adverse events were cytopenias, febrile neutropenia, and infection. There were no dose-limiting toxicities. Entospletinib-related skin rash and hyperbilirubinemia were also observed. Conclusions: Entospletinib with intensive chemotherapy was well-tolerated in patients with AML. Improved survival was observed in patients with HOXA9/MEIS1 overexpression, contrasting published data demonstrating poor survival in such patients. A randomized study will be necessary to determine whether entospletinib was a mediator this observation.

Background: ENA is an oral, selective inhibitor of IDH2 approved for the treatment (Tx) of patients (pts) with relapsed/refractory IDH2 mutated (IDH2m) AML. Here we report the results of a Phase 2 expansion and Phase 1b of the Beat AML Master Trial Phase 2/1b sub-study to assess the efficacy of Tx of newly diagnosed (ND) IDH2m AML pts ≥ 60 years of age with ENA monotherapy (ENAm) and subsequent response-driven addition of AZA Tx. (ClinicalTrials.gov NCT03013998). Methods: The study initiated with a 3-outcome, 2-stage Phase 2 design, which enrolled patients on ENAm for up to 5 cycles. Pts without CR/CRi after 5 cycles of ENAm, or progression/intolerance prior to this time, were transferred to Phase 1b to receive ENA + AZA (Figure 1). Key eligibility included ND IDH2m AML pts with age ≥ 60 years and ECOG performance status 0-2. Pts received ENAm 100 mg/day in continuous 28-day cycles and ENA + AZA (75 mg/m2 days 1-7 every 28 days) for Phase 1b. Response was assessed using 2017 ELN AML criteria. The primary endpoint was CR/CRi rate. The 2-stage design required 24 pts and tested the null hypothesis (H0) that CR/CRi rate equaled 20% vs 50% and then expanded to test a revised H0 of 30% vs 50% in 60 pts (conditional alpha=0.025, power=77%). Expansion also allowed further assessment of safety of this treatment regimen. Results: At data cut off (06/18/2020), 60 pts enrolled, received ENAm, and were evaluable for the primary endpoint. Median age was 75 years and 52% were female (Table 1). Median time on ENAm was 4.7 months (mos). At data cut off, 12 pts were still on ENAm Tx. Most common reasons for discontinuing ENAm were Tx failure (defined as no response to treatment) (23 or 38%), disease progression (loss of response to treatment) (7 or 12%) and adverse events (AEs; 6 or 10%). Five pts (8%) went to transplant. CR/CRi was achieved in 28 pts (47%; adjusted 95% CI 28-59, unadjusted exact 95% CI 34-60) (Table 2). Responses were higher (p=0.04) among the 44 pts with IDH2 R140 (55%) as compared to the 16 with IDH2 R172 mutation (25%) further supporting distinct biology between these subsets. After a median follow up of 14.6 mos, the median overall survival (mOS) was 24.4 mos (95% CI 10.6-not reached). The median duration of response was not reached with 12 mos estimation of 57% (95% CI 34-75). Overall, 20 ENA-related serious adverse events (SAEs) occurred in 15 pts, the most common was differentiation syndrome (12 or 20%) and 1 had ENA-related SAE of tumor lysis syndrome (1.7%). One pt had ENA-related Grade 5 AE (renal failure/death). Most common AEs of any grade (in ≥20%) were nausea, anemia, and low potassium (Table 3). The 7-day/30-day/60-day deaths observed with ENAm were 2%/5%/11%, respectively. Phase 1b: Seventeen pts had inadequate response to ENAm and transferred to Phase 1b to receive ENA + AZA. Median time on Tx (including ENAm) was 6.2 mos and median time on Tx after pts started ENA + AZA was 2.1 mos (Table 2). Most common reasons for discontinuing ENA + AZA included Tx failure (5 or 29%), disease progression (2 or 12%), transplant, death and AEs (each 2 or 12%). CR/CRi was 41% (exact 95% CI 18-67). After a median follow up of 12.7 mos, the mOS from start of ENA + AZA combination Tx was 8.9 mos. Four ENA-related SAEs occurred in 3 pts on ENA + AZA Tx and the most common was differentiation syndrome (2 or 12.5%). One dose-limiting toxicity (Grade 3 nausea) related to both Txs was observed. Most common AEs (≥20%) of any grade were anemia, low albumin and vomiting (Table 3). One death occurred at day 13 of ENA + AZA. Conclusions: In newly diagnosed pts ≥60 years old with IDH2m AML, ENA had a low early death rate, high CR/CRi rate (47%, adjusted 95% CI 28-59), and yielded durable remissions. The most common unique toxicity with ENA was differentiation syndrome that occurred in 20% of patients. In pts who did not achieve CR/CRi with ENAm, a subset of patients achieved CR/CRi with addition of AZA. This combined approach of serial therapy with ENA monotherapy followed by AZA addition in pts with sub-optimal response resulted in a mOS exceeding 2 years for pts enrolled on study. Further focus on improving response among patients with IDH2 R172 mutations, identifying subsets of pts not responding to ENA monotherapy, and integrating new targeted agents into this treatment regimen are warranted. Figure 1 Disclosures Stein: Syndax: Consultancy, Research Funding; Celgene Pharmaceuticals: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding; Daiichi-Sankyo: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding; Astellas Pharmaceuticals: Consultancy, Membership on an entity's Board of Directors or advisory committees; Seattle Genetics: Consultancy; Agios Pharmaceuticals: Consultancy, Membership on an entity's Board of Directors or advisory committees; Bayer: Research Funding; Genentech: Consultancy, Membership on an entity's Board of Directors or advisory committees; Amgen: Consultancy; Biotheryx: Consultancy; Novartis: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding; PTC Therapeutics: Membership on an entity's Board of Directors or advisory committees; Syros: Membership on an entity's Board of Directors or advisory committees; Abbvie: Consultancy. Borate:Genentech: Membership on an entity's Board of Directors or advisory committees; Daiichi Sankyo: Membership on an entity's Board of Directors or advisory committees; Takeda: Membership on an entity's Board of Directors or advisory committees, Research Funding; Novartis: Membership on an entity's Board of Directors or advisory committees, Research Funding; Jazz Pharmaceuticals: Research Funding; AbbVie: Other: Investigator in AbbVie-funded clinical trials; Pfizer: Membership on an entity's Board of Directors or advisory committees, Research Funding. Baer:Takeda: Other: Institutional research funding; AbbVie: Other: Institutional research funding; Astellas: Other: Institutional research funding; Forma: Other: Institutional research funding; Kite: Other: Institutional research funding; Oscotec: Other: Institutional research funding; Incyte: Other: Institutional research funding. Kovacsovics:Agios: Honoraria; Astella: Honoraria; Pfizer: Research Funding; Novartis: Research Funding; AbbVie: Research Funding; Jazz: Honoraria. Schiller:Astellas Pharma: Honoraria, Research Funding; Celator: Research Funding; Constellation: Research Funding; Abbvie: Research Funding; Actinium: Research Funding; Ariad: Research Funding; Stemline: Speakers Bureau; Cyclacel: Research Funding; Daiichi Sankyo: Research Funding; Deciphera: Research Funding; DeltaFly: Research Funding; Bristol-Myers Squibb: Current equity holder in publicly-traded company, Research Funding; Forma: Research Funding; FujiFilm: Research Funding; Gamida: Research Funding; Genentech-Roche: Research Funding; Geron: Research Funding; Jazz Pharmaceuticals: Research Funding; Karyopharm: Research Funding; Kite Pharma: Research Funding; Mateon: Research Funding; MedImmune: Research Funding; Onconova: Research Funding; Pfizer: Current equity holder in publicly-traded company, Research Funding; Regimmune: Research Funding; Samus: Research Funding; Sangamo: Research Funding; Tolero: Research Funding; Trovagene: Research Funding; Kaiser Permanente: Consultancy; Johnson & Johnson: Current equity holder in publicly-traded company; Agios: Consultancy, Research Funding, Speakers Bureau; Amgen: Consultancy, Current equity holder in publicly-traded company, Research Funding, Speakers Bureau; AstraZeneca: Consultancy; Incyte: Consultancy, Research Funding, Speakers Bureau; Novartis: Consultancy, Research Funding; Ono Pharma: Consultancy; Celgene: Research Funding, Speakers Bureau; Sanofi: Speakers Bureau; Gilead: Speakers Bureau. Olin:Astellas: Other: Site PI; Genentech: Other: Site PI; Pfizer: Other: Site PI; Daiichi Sankyo: Other: Site PI; Genentech: Consultancy; Amgen: Consultancy. Foran:Trillium: Research Funding; Xencor: Research Funding; H3Biosciences: Research Funding; Agios: Honoraria, Research Funding; Pfizer: Membership on an entity's Board of Directors or advisory committees; BMS: Membership on an entity's Board of Directors or advisory committees; Abbvie: Research Funding; Boehringer Ingelheim: Research Funding; Actinium: Research Funding; Aprea: Research Funding; Aptose: Research Funding; Kura Oncology: Research Funding; Takeda: Research Funding; Revolution Medicine: Consultancy; Novartis: Membership on an entity's Board of Directors or advisory committees; Servier: Membership on an entity's Board of Directors or advisory committees. Lin:Trovagene: Research Funding; Tolero Pharmaceuticals: Research Funding; Seattle Genetics: Research Funding; Prescient Therapeutics: Research Funding; Abbvie: Research Funding; Bio-Path Holdings: Research Funding; Astellas Pharma: Research Funding; Aptevo: Research Funding; Incyte: Research Funding; Pfizer: Research Funding; Mateon Therapeutics: Research Funding; Ono Pharmaceutical: Research Funding; Jazz: Research Funding; Gilead Sciences: Research Funding; Genetech-Roche: Research Funding; Celyad: Research Funding; Celgene: Research Funding. Patel:DAVA Pharmaceuticals: Honoraria; Celgene: Consultancy, Speakers Bureau; Agios: Consultancy; France Foundation: Honoraria. Foster:Daiichi Sankyo: Consultancy; Bellicum Pharmaceuticals: Research Funding; Macrogenics: Consultancy, Research Funding. Druker:Leukemia & Lymphoma Society: Research Funding; Henry Stewart Talks: Patents & Royalties; Iterion Therapeutics (formerly Beta Cat Pharmaceuticals): Membership on an entity's Board of Directors or advisory committees; Vivid Biosciences: Membership on an entity's Board of Directors or advisory committees; GRAIL: Consultancy, Current equity holder in private company, Membership on an entity's Board of Directors or advisory committees; Patient True Talks: Consultancy; The RUNX1 Research Program: Membership on an entity's Board of Directors or advisory committees; Third Coast Therapeutics: Membership on an entity's Board of Directors or advisory committees; VB Therapeutics: Membership on an entity's Board of Directors or advisory committees; Gilead Sciences: Consultancy, Membership on an entity's Board of Directors or advisory committees; Millipore (formerly Upstate Biotechnology): Patents & Royalties; MolecularMD (acquired by ICON): Consultancy, Current equity holder in publicly-traded company, Membership on an entity's Board of Directors or advisory committees; Novartis Pharmaceuticals: Membership on an entity's Board of Directors or advisory committees, Patents & Royalties, Research Funding; McGraw Hill: Patents & Royalties; Merck & Co: Patents & Royalties; Cepheid: Consultancy, Membership on an entity's Board of Directors or advisory committees; Dana-Farber Cancer Institute: Patents & Royalties; EnLiven: Consultancy, Research Funding; Aptose Therapeutics Inc. (formerly Lorus): Consultancy, Current equity holder in publicly-traded company, Membership on an entity's Board of Directors or advisory committees; ARIAD: Research Funding; Blueprint Medicines: Consultancy, Current equity holder in private company, Membership on an entity's Board of Directors or advisory committees; ALLCRON: Consultancy, Membership on an entity's Board of Directors or advisory committees; Amgen: Current equity holder in publicly-traded company, Membership on an entity's Board of Directors or advisory committees; Bristol-Myers Squibb: Research Funding; Aileron Therapeutics: Membership on an entity's Board of Directors or advisory committees; Pfizer: Research Funding; Oregon Health & Science University: Patents & Royalties. Byrd:Acerta Pharma: Research Funding; Syndax: Research Funding; Vincera: Research Funding; Pharmacyclics LLC, an AbbVie Company, Janssen, Novartis, Gilead, TG Therapeutics: Other; Pharmacyclics LLC, an AbbVie Company, Gilead, TG Therapeutics, Novartis, Janssen: Speakers Bureau; Novartis: Research Funding; Kartos Therapeutics: Research Funding; Trillium: Research Funding; Leukemia and Lymphoma Society: Other; Janssen: Consultancy; Pharmacyclics LLC, an AbbVie Company, Gilead, TG Therapeutics, BeiGene: Research Funding. Levine:Loxo: Current equity holder in private company, Membership on an entity's Board of Directors or advisory committees; C4 Therapeutics: Current equity holder in private company, Membership on an entity's Board of Directors or advisory committees; Imago: Current equity holder in private company, Membership on an entity's Board of Directors or advisory committees; Celgene: Consultancy, Honoraria, Research Funding; Qiagen: Current equity holder in publicly-traded company, Membership on an entity's Board of Directors or advisory committees; Prelude Therapeutics: Research Funding; Amgen: Honoraria; Astellas: Consultancy; Morphosys: Consultancy; Novartis: Consultancy; Isoplexis: Current equity holder in private company, Membership on an entity's Board of Directors or advisory committees; Janssen: Consultancy; Lilly: Consultancy, Honoraria; Roche: Consultancy, Honoraria, Research Funding; Gilead: Honoraria. Mims:Abbvie: Membership on an entity's Board of Directors or advisory committees; Kura Oncology: Membership on an entity's Board of Directors or advisory committees; Leukemia and Lymphoma Society: Other: Senior Medical Director for Beat AML Study; Jazz Pharmaceuticals: Other: Data Safety Monitoring Board; Syndax Pharmaceuticals: Membership on an entity's Board of Directors or advisory committees; Agios: Consultancy; Novartis: Speakers Bureau. OffLabel Disclosure: Enasidenib is not approved for the treatment of newly diagnosed AML.

PURPOSE: Patients with acute myeloid leukemia with high-risk cytogenetics in first complete remission (CR1) achieve better outcomes if they undergo allogeneic hematopoietic cell transplantation (HCT) compared with consolidation chemotherapy alone. However, only approximately 40% of such patients typically proceed to HCT. METHODS: We used a prospective organized approach to rapidly identify donors to improve the allogeneic HCT rate in adults with high-risk acute myeloid leukemia in CR1. Newly diagnosed patients had cytogenetics obtained at enrollment, and those with high-risk cytogenetics underwent expedited HLA typing and were encouraged to be referred for consultation with a transplantation team with the goal of conducting an allogeneic HCT in CR1. RESULTS: Of 738 eligible patients (median age, 49 years; range, 18-60 years of age), 159 (22%) had high-risk cytogenetics and 107 of these patients (67%) achieved CR1. Seventy (65%) of the high-risk patients underwent transplantation in CR1 ( P < .001 compared with the historical rate of 40%). Median time to HCT from CR1 was 77 days (range, 20-356 days). In landmark analysis, overall survival (OS) among patients who underwent transplantation was significantly better compared with that of patients who did not undergo transplantation (2-year OS, 48% v 35%, respectively [ P = .031]). Median relapse-free survival after transplantation in the high-risk cohort who underwent transplantation in CR1 (n = 70) was 11.5 months (range, 4-47 months), and median OS after transplantation was 14 months (range, 4-44 months). CONCLUSION: Early cytogenetic testing with an organized effort to identify a suitable allogeneic HCT donor led to a CR1 transplantation rate of 65% in the high-risk group, which, in turn, led to an improvement in OS when compared with the OS of patients who did not undergo transplantation.

Simple Summary Cytokine release syndrome is a potentially life-threatening complication of therapy with T-cell engaging bispecific antibodies. Here we evaluated the risk, characteristics and biomarkers of treatment-emergent cytokine release syndrome in patients with relapsed/refractory acute myeloid leukemia or myelodysplastic syndrome who received weekly intravenous infusions of the CD3xCD123 bispecific antibody APVO436. Cytokine release syndrome was encountered in 10 of 46 patients (21.7%) treated with APVO436 with a cumulative Grade 3/4 cytokine release syndrome incidence of 8.7%. Cytokine profiling in patients who developed cytokine release syndrome after APVO436 infusion indicated that the predominant cytokine in this inflammatory cytokine response was IL-6. The findings from this research provide new insights regarding the biology and effective management of cytokine release syndrome in leukemia patients treated with T-cell redirecting bispecific antibodies. Abstract We evaluate the risk, characteristics and biomarkers of treatment-emergent cytokine release syndrome (CRS) in patients with relapsed/refractory acute myeloid leukemia (AML) or myelodysplastic syndrome (MDS) who received APVO436 during the dose-escalation phase of a Phase 1B study (ClinicalTrials.gov, identifier: NCT03647800). Of four patients who developed Grade ≥ 3 CRS, two received steroid prophylaxis. The dose level, gender, race, obesity, or baseline hematologic parameters in peripheral blood did not predict the risk of CRS. Patients with a higher leukemia burden as determined by a higher total WBC, higher percentage of blasts in bone marrow, or higher percentage of blasts in peripheral blood (by hematopathology or immunophenotyping) did not have a higher incidence of CRS. There was an age difference between patients who did versus patients who did not develop CRS (72.9 ± 1.6 years (Median 73.5 years) vs. 63.3 ± 2.3 years (Median: 65.0 years), which was borderline significant (p = 0.04). Premedication with steroids did not eliminate the risk of CRS. Cytokine profiling in patients who developed CRS after APVO436 infusion indicates that the predominant cytokine in this inflammatory cytokine response was IL-6. APVO436-associated CRS was generally manageable with tocilizumab with or without dexamethasone. Notably, the development of CRS after APVO436 therapy did not appear to be associated with a response. The prolonged stabilization of disease, partial remissions and complete remissions were achieved in both patients who experienced CRS, as well as patients who did not experience CRS after APVO436 infusions.

Simple Summary AML is a common form of blood cancer in adults. This study was undertaken to evaluate if AML patients who have failed the available standard treatment options could tolerate and potentially benefit from a new form of therapy. This new therapy activates patients’ own immune system against AML cells. The findings from this research may provide the foundation for a potentially more effective future form of standard therapy that is less likely to fail. Abstract APVO436 is a recombinant T cell-engaging humanized bispecific antibody designed to redirect host T cell cytotoxicity in an MHC-independent manner to CD123-expressing blast cells from patients with hematologic malignancies and has exhibited single-agent anti-leukemia activity in murine xenograft models of acute myeloid leukemia (AML). In this first-in-human (FIH) multicenter phase 1B study, we sought to determine the safety and tolerability of APVO436 in R/R AML/myelodysplastic syndrome (MDS) patients and identify a clinically active recommended phase 2 dose (RP2D) level for its further clinical development. A total of 46 R/R AML/MDS patients who had failed 1–8 prior lines of therapy received APVO436 as weekly intravenous (IV) infusions at 10 different dose levels, ranging from a Minimum Anticipated Biological Effect Level (MABEL) of 0.3 mcg to 60 mcg. APVO436 exhibited a favorable safety profile with acceptable tolerability and manageable drug-related adverse events (AEs), and its maximum tolerated dose (MTD) was not reached at a weekly dose of 60 mcg. The most common APVO436-related AEs were infusion-related reactions (IRR) occurring in 13 (28.3%) patients and cytokine release syndrome (CRS) occurring in 10 (21.7%). The single dose RP2D level was identified as 0.2 mcg/kg. Preliminary efficacy signals were observed in both AML and MDS patients: Prolonged stable disease (SD), partial remissions (PR), and complete remissions (CR) were observed in R/R AML patients as best overall responses to APVO436 at the RP2D level. Three of six evaluable MDS patients had marrow CRs. The safety and preliminary evidence of efficacy of APVO436 in R/R AML and MDS patients warrant further investigation of its clinical impact potential.

Introduction: CPX-351 (Vyxeos®; daunorubicin and cytarabine liposome for injection), a dual-drug liposomal encapsulation of daunorubicin and cytarabine in a synergistic 1:5 molar drug ratio, has been approved by the US FDA and EMA for the treatment of adults with newly diagnosed therapy-related AML or AML with myelodysplasia-related changes. A randomized phase 3 study that evaluated patients 60 to 75 years of age with newly diagnosed high-risk/secondary AML provided the basis for approval and demonstrated that induction followed by consolidation with CPX-351 significantly improved overall survival and remission rates versus conventional 7+3, with a comparable safety profile. Several targeted therapies have demonstrated efficacy when added to cytotoxic therapy for the treatment of patients with previously untreated AML, including venetoclax (Venclexta®/Venclyxto®; a B-cell leukemia/lymphoma-2 [BCL-2] inhibitor), midostaurin (Rydapt®; a FMS-related tyrosine kinase 3 [FLT3] inhibitor), and enasidenib (Idhifa®; an isocitrate dehydrogenase 2 [IDH2] inhibitor). Preclinical data indicate synergistic activity may be achieved with CPX-351 in combination with venetoclax or midostaurin. Results of these studies suggest a rationale for the combination of targeted therapies using CPX-351 as a chemotherapy backbone. Study Design and Methods: V-FAST (Vyxeos - First Phase Assessment with Targeted Agents) is an open-label, multicenter, multi-arm, nonrandomized, phase 1b master trial (ClinicalTrials.gov #NCT04075747) to evaluate CPX-351 in combination with targeted agents (venetoclax, midostaurin, or enasidenib) in adults with previously untreated AML who are considered fit for intensive chemotherapy. As V-FAST is a master trial, it is designed to permit the expedited incorporation of CPX-351 combinations with other targeted agents into the study as it proceeds, thus ensuring a timely investigation of novel combinations moving forward. Key eligibility criteria are shown in Table 1. The primary study endpoints are to establish the recommended phase 2 dose (RP2D) and safety of each combination regimen. Secondary endpoints include remission rates (via morphologic assessment), bone marrow measurable residual disease status, and pharmacokinetics. Exploratory endpoints include duration of remission, overall survival, event-free survival, and the proportion of patients proceeding to hematopoietic cell transplantation. Patients will be monitored for safety until 1 month following the end of treatment and survival for up to 2 years following the first administration of treatment. Cytogenetic and/or molecular testing will determine which treatment arm each patient is assigned to (ie, no FLT3 or IDH2 mutations: CPX-351 plus venetoclax; FLT3 mutation: CPX-351 plus midostaurin; IDH2 mutation: CPX-351 plus enasidenib). For each combination, a dose-exploration phase (standard 3+3 design; up to 12 patients/combination) will employ dose de-escalation or escalation of CPX-351 and/or the targeted agent based on the occurrence of dose-limiting toxicities to determine a RP2D and evaluate the safety of the combination. The initial cohort for each arm will be treated with the dosing described in Table 2. In the subsequent expansion phase for each combination, an additional 20 patients will be treated to confirm the RP2D, further evaluate safety, and provide an initial assessment of efficacy. In both study phases, CPX-351 will be administered intravenously by 90-minute infusion on Days 1, 3, and 5; targeted therapies will be administered per a standard route for each agent. Patients may receive 1 to 2 induction cycles of combination therapy. Those achieving remission may receive up to 2 consolidation cycles with CPX-351 plus the targeted agent received during induction; hematopoietic stem cell transplantation is permitted in place of or following chemotherapy consolidation at the discretion of the treating physician. This study is ongoing and actively enrolling patients. Disclosures Lin: Celgene: Research Funding; Aptevo: Research Funding; Abbvie: Research Funding; Astellas Pharma: Research Funding; Ono Pharmaceutical: Research Funding; Mateon Therapeutics: Research Funding; Prescient Therapeutics: Research Funding; Pfizer: Research Funding; Celyad: Research Funding; Genetech-Roche: Research Funding; Gilead Sciences: Research Funding; Incyte: Research Funding; Trovagene: Research Funding; Tolero Pharmaceuticals: Research Funding; Seattle Genetics: Research Funding; Bio-Path Holdings: Research Funding; Jazz: Research Funding. Mannis:AbbVie, Agios, Bristol-Myers Squibb, Genentech: Consultancy; Glycomimetics, Forty Seven, Inc, Jazz Pharmaceuticals: Research Funding. Erba:Glycomimetics: Other: member of Scientific Steering Committee; AbbVie, Daiichi Sankyo, Forma, ImmunoGen, Jazz Pharmaceuticals, MacroGenics, Novartis, PTC: Research Funding; AbbVie, Agios, Celgene, Incyte, Jazz Pharmaceuticals, and Novartis: Speakers Bureau; AbbVie, Agios, Amgen, Astellas, Celgene, Daiichi Sankyo, Glycomimetics, ImmunoGen, Incyte, Jazz Pharmaceuticals, MacroGenics, Novartis, and Pfizer: Consultancy; Celgene: Other: chair of the Scientific Steering Committee; Covance (AbbVie): Other: chair of the Independent Review Committee. Levis:Daiichi-Sankyo: Honoraria; FujiFilm: Honoraria, Research Funding; Astellas: Honoraria, Research Funding; Amgen: Honoraria; Menarini: Honoraria. Zou:Jazz Pharmaceuticals: Current Employment, Current equity holder in publicly-traded company. Faderl:Jazz Pharmaceuticals: Current Employment, Current equity holder in publicly-traded company. Cheung:Jazz Pharmaceuticals: Current Employment, Current equity holder in publicly-traded company. Pullarkat:Amgen: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; AbbVie, Inc.: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Genetech: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Pfizer: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Jazz Pharmaceuticals: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Dova: Consultancy, Honoraria; Servier: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Novartis: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau. OffLabel Disclosure: This study will explore CPX-351 in combination with targeted agents for the treatment of adults with AML.

Background CPX-351 (United States: Vyxeos®; Europe: Vyxeos® Liposomal), a dual-drug liposomal encapsulation of daunorubicin and cytarabine in a synergistic 1:5 molar ratio, is approved by the US FDA and the EMA for the treatment of adults with newly diagnosed therapy-related acute myeloid leukemia or acute myeloid leukemia with myelodysplasia-related changes. In a pivotal phase 3 study that evaluated 309 patients aged 60 to 75 years with newly diagnosed high-risk/secondary acute myeloid leukemia, CPX-351 significantly improved median overall survival versus conventional 7 + 3 chemotherapy (cytarabine continuous infusion for 7 days plus daunorubicin for 3 days), with a comparable safety profile. A Quality‐adjusted Time Without Symptoms of disease or Toxicity (Q-TWiST) analysis of the phase 3 study was performed to compare survival quality between patients receiving CPX-351 versus conventional 7 + 3 after 5 years of follow-up. Methods Patients were randomized 1:1 between December 20, 2012 and November 11, 2014 to receive induction with CPX-351 or 7 + 3. Survival time for each patient was partitioned into 3 health states: TOX (time with any grade 3 or 4 toxicity or prior to remission), TWiST (time in remission without relapse or grade 3 or 4 toxicity), and REL (time after relapse). Within each treatment arm, Q-TWiST was calculated by adding the mean time spent in each health state weighted by its respective quality-of-life, represented by health utility. The relative Q-TWiST gain, calculated as the difference in Q-TWiST between treatment arms divided by the mean survival of the 7 + 3 control arm, was determined in order to evaluate results in the context of other Q-TWiST analyses. Results The relative Q-TWiST gain with CPX-351 versus 7 + 3 was 53.6% in the base case scenario and 39.8% among responding patients. Across various sensitivity analyses, the relative Q-TWiST gains for CPX-351 ranged from 48.0 to 57.6%, remaining well above the standard clinically important difference threshold of 15% for oncology. Conclusions This post hoc analysis demonstrates that CPX-351 improved quality-adjusted survival, further supporting the clinical benefit in patients with newly diagnosed high-risk/secondary acute myeloid leukemia. Trial registration This trial was registered on September 28, 2012 at www.clinicaltrials.gov as NCT01696084 (https://clinicaltrials.gov/ct2/show/NCT01696084) and is complete.

Purpose Daunorubicin can induce left ventricular dysfunction and QT interval prolongation. This study assessed the effects of CPX-351, a liposomal encapsulation of cytarabine and daunorubicin, on cardiac repolarization. Methods Twenty-six adults with acute leukemia were treated with CPX-351 for 1–2 induction cycles and ≤ 4 consolidation cycles. The primary endpoint was mean change in QTcF from baseline. Results Mean QTcF changes were 30 h. Thirteen (50%) patients achieved remission. The most common adverse events were febrile neutropenia, fatigue, and nausea. Conclusions The cytarabine and daunorubicin in CPX-351 liposomes were metabolized and excreted similarly to conventional formulation; however, plasma pharmacokinetics were altered. CPX-351 did not prolong the QT interval, suggesting that CPX-351 may induce less cardiotoxicity than previously reported for conventional daunorubicin. Trial registration Clinicaltrials.gov identifier: NCT02238925. Electronic supplementary material The online version of this article (10.1007/s00280-019-03856-9) contains supplementary material, which is available to authorized users.

Umbilical cord blood (UCB) transplantation is a promising option for hematopoietic stem cell transplantation in patients with hematologic malignancies who lack an HLA-matched sibling or well-matched unrelated donor; however, it has a higher incidence of delayed or failed engraftment because cell doses are low and bone marrow homing is inefficient. We have demonstrated that pre-treating irradiated immune-deficient mice with hyperbaric oxygen (HBO) prior to UCB CD34+ cell transplantation lowered host systemic erythropoietin (EPO) and improved UCB CD34+ cell homing and engraftment. These findings suggested that EPO-EPO-R signaling plays a role in UCB CD34+ homing and engraftment. In a pilot clinical trial, we showed that recipients of HBO therapy prior to UCB cell infusion had reduced systemic EPO, which was associated with improved kinetics of blood count recovery. Although early clinical outcomes at day 100 were encouraging, with improved overall survival, the long-term effects of HBO therapy on UCB-transplanted patients were not evaluated. In this study, we examined the long-term outcome of patients in our pilot study, compared with a historic control group, and correlated their clinical outcomes to serum EPO response to HBO. While 50% of HBO-treated patients received single UCB units, ~ 90% of the control patients received double UCB units. Although HBO patients had much better rates of survival at 6 months, their 1-year survival did not significantly differ from the control group. HBO-treated patients had on average lower relapse and non-relapse mortality rates, and less chronic graft versus host disease (GVHD), but had increased acute GVHD. However, these differences were not statistically significant, probably because of the small sample size. In the HBO-treated cohort, immune reconstitution analysis showed significant improvement in early B cell recovery, with a trend toward improvement in early NK cell recovery. When we evaluated the ratio of 8 h to baseline EPO levels, we found a non-significant trend toward lower EPO values in those who neither relapsed nor died by 1 year, compared to those who died or relapsed. This result suggests that EPO response to HBO may be associated with better outcomes. Disease progression-free survival was also improved in those who had more than 80% reduction in EPO levels in response to HBO. Our study highlights the long-term safety of HBO therapy when used prior to UCB transplantation. Future UCB transplant patients who receive HBO should have their serum EPO response measured, as it may be a marker of relapse/mortality.

Acute myeloid leukemia (AML) is the most common diagnosed leukemia. In older adults, AML confers an adverse outcome1,2. AML originates from a dominant mutation, then acquires collaborative transformative mutations leading to myeloid transformation and clinical/biological heterogeneity. Currently, AML treatment is initiated rapidly, precluding the ability to consider the mutational profile of a patient’s leukemia for treatment decisions. Untreated patients with AML ≥ 60 years were prospectively enrolled on the ongoing Beat AML trial (ClinicalTrials.gov NCT03013998 ), which aims to provide cytogenetic and mutational data within 7 days (d) from sample receipt and before treatment selection, followed by treatment assignment to a sub-study based on the dominant clone. A total of 487 patients with suspected AML were enrolled; 395 were eligible. Median age was 72 years (range 60–92 years; 38% ≥75 years); 374 patients (94.7%) had genetic and cytogenetic analysis completed within 7 d and were centrally assigned to a Beat AML sub-study; 224 (56.7%) were enrolled on a Beat AML sub-study. The remaining 171 patients elected standard of care (SOC) (103), investigational therapy (28) or palliative care (40); 9 died before treatment assignment. Demographic, laboratory and molecular characteristics were not significantly different between patients on the Beat AML sub-studies and those receiving SOC (induction with cytarabine + daunorubicin (7 + 3 or equivalent) or hypomethylation agent). Thirty-day mortality was less frequent and overall survival was significantly longer for patients enrolled on the Beat AML sub-studies versus those who elected SOC. A precision medicine therapy strategy in AML is feasible within 7 d, allowing patients and physicians to rapidly incorporate genomic data into treatment decisions without increasing early death or adversely impacting overall survival. Preliminary results from the Beat AML umbrella trial demonstrates the feasibility and efficacy of applying prospective genomic profiling for matching newly diagnosed patients with AML with targeted therapies.

Background: Acute myeloid leukemia (AML) is a clonal hematologic malignancy that generally affects older adults. Despite achieving complete remission (CR) in over two-third of patients with initial induction therapy and subsequent allogeneic hematopoietic stem cell transplantation in intermediate-high risk patients, more than half of AML patients experience disease relapse. The prognosis of patients with relapsed/refractory AML (RR-AML) is often poor and treatment modalities are limited. Chimeric antigen receptor T cell (CAR-T) therapy has shown promising results in lymphoid malignancies and myeloma, and these are now being explored for the management of RR-AML. In this systematic review and meta-analysis, we aimed to investigate the outcomes of CAR-T therapy in RR-AML patients. Methods: Following the Preferred Reporting Items for Systematic Reviews and Meta-Analysis (PRISMA) guidelines, a comprehensive literature search was conducted on three databases (PubMed, Cochrane Register of Controlled Trials, and Clinical trials.gov) using MeSH terms and keywords for "Leukemia, Myeloid, Acute" AND "Receptors, Chimeric Antigen" OR "adoptive immunotherapy" from the date of inception to April 2021. A total of 673 articles were screened and original studies reporting patients with RR-AML having CAR-T therapy as the only intervention were included while reviews, duplicate, and non-relevant articles were excluded. A total of 10 studies (8 clinical trials and 2 case reports) were included. The data for following outcomes were extracted: complete response (CR), partial response (PR), overall response rate (ORR), overall survival (OS), progression-free survival (PFS), stable disease (SD), progressive disease (PD), cytokine release syndrome (CRS) and neurotoxicity (NT). Quality evaluation was done using the NIH quality assessment tool. Inter-study variance was calculated using the Der Simonian-Laird Estimator. Proportions along with 95% confidence Interval (CI) were extracted to compute pooled analysis using the 'meta' package by Schwarzer et al. in the R programming language (version 4.16-2). Results: We identified 39 patients in 10 studies who received CAR-T therapy for RR-AML. Median age of patients was 35 (7.3-80) years and 59% (n=23) were male. The median follow-up time was 5 (0.7-23) months. (Table 1) Four patients had history of allogeneic hematopoietic stem cell transplant (HCT) prior to CAR-T therapy while subsequent HCT was performed in 5 patients. The pooled analysis showed a CR and ORR of 38.5% (95% CI 0.03-0.81, I 2 =66%, n=29) and 56% (CI 0.18-0.91, I 2=58%, n=29), respectively. Median duration of response was 5.5 (1-23) months. OS was reported from 1.9 months to 23 months. The pooled incidence of CRS and NT were 42.7% (95%CI 0.06-0.87, I 2=66%, n=28) and 1.3% (95% CI 0.00-0.16, I 2= 0%, n=21) respectively. Graft-versus-host disease (GVHD) was reported in 2 patients who had prior and subsequent HCT after CAR-T therapy; first patient developed grade IV GVHD in the setting of salvage therapy with donor lymphocyte infusions for relapsed disease 6 months' post CAR-T and 4 months post second allo-HCT while second patient received CAR-T as part of conditioning therapy and developed grade IV GVHD on day 32. Conclusion: CAR-T therapy has shown favorable results comparable to current salvage therapies for relapsed or refractory AML with an acceptable toxicity profile. However, there are several challenges including the heterogeneous biology of AML, lack of a targetable antigen expression on malignant cells, and immune escape and exhaustion. Future prospective studies with improved CAR-T constructs will hopefully improve the outcomes in this therapeutically challenging patient population. Figure 1 Figure 1. Disclosures Lin: AbbVie, Aptevo Therapeutics, Astellas Pharma, Bio-Path Holdings, Celgene, Celyad, Genentech-Roche, Gilead Sciences, Incyte, Jazz Pharmaceuticals, Novartis, Ono Pharmaceutical, Pfizer, Prescient Therapeutics, Seattle Genetics, Tolero, Trovagene: Research Funding. Abhyankar: Incyte/Therakos: Consultancy, Research Funding, Speakers Bureau. McGuirk: EcoR1 Capital: Consultancy; Juno Therapeutics: Consultancy, Honoraria, Research Funding; Pluristem Therapeutics: Research Funding; Bellicum Pharmaceuticals: Research Funding; Gamida Cell: Research Funding; Novartis: Research Funding; Astelllas Pharma: Research Funding; Kite/ Gilead: Consultancy, Honoraria, Other: travel accommodations, expense, Kite a Gilead company, Research Funding, Speakers Bureau; Fresenius Biotech: Research Funding; Novartis: Research Funding; Magenta Therapeutics: Consultancy, Honoraria, Research Funding; Allovir: Consultancy, Honoraria, Research Funding.

Patients with mutated and overexpressed p53 have an aggressive course in acute myeloid leukemia (AML) and myelodysplastic syndrome (MDS). Studies on the impact of MYC expression in AML are limited. This is the first study to evaluate MYC expression and p53 status in AML and MDS.We identified 214 patients, 101 AML, 79 MDS, and 34 negative control patients. We retrospectively assessed p53 and MYC expression by immunohistochemistry and correlated MYC expression with p53 expression and aberrational status of TP53.The level of both p53 and MYC expression was significantly higher in AML (mean: 9.7%; 12.1%) and MDS (mean: 5.2%; 5.5%) patients compared with control cases (mean: 0.18%; 2.3%; P = .001-0.02). p53 and MYC expression levels were even more elevated in AML when compared to MDS patients (P .001). MYC expression was significantly associated with p53 expression and TP53 aberration in AML patients but not in MDS patients (P .001). p53 expression and20% MYC expression showed an adverse impact on overall survival (OS) (P .05) in AML patients while p53 but not MYC expression showed an adverse impact on OS in MDS patients. MYC and p53 dual expression, as well as combined MYC expression and TP53 aberration, showed negative impact on OS in AML patients. MDS patients with leukemic transformation revealed an interval increase in expression of both p53 and MYC.High-level MYC expression associates with p53 abnormality and poor survival in AML. MYC may provide proliferative advantage for leukemic progression in p53 dependent and independent manner.

Introduction: Gemtuzumab ozogamicin (GO; MylotargTM) is an antibody-drug conjugate composed of an anti-CD33 monoclonal antibody covalently linked to the potent antibiotic calicheamicin. Previous studies have shown GO is generally well tolerated and can induce durable second remissions when administered as monotherapy or in combination with chemotherapy in patients with relapsed or refractory (R/R) acute myeloid leukemia (AML). We report safety data from an expanded-access protocol (EAP) that allowed compassionate use of GO in patients with R/R AML or acute promyelocytic leukemia (APL) and no access to comparable or alternative therapy. Methods: Conducted in the United States, the GO EAP (NCT02312037) was an open-label study in patients aged ≥3 months with R/R AML (including myelodysplastic syndrome) or APL who were considered to have the potential to derive clinical benefit and had exhausted other treatment options. The protocol allowed for treatment regimens tested in clinical trial settings and reported in the Mylotarg Investigators Brochure or peer-reviewed journals. Data from these trials indicated these regimens could potentially benefit a patient with R/R AML or APL. For R/R AML patients, the regimens included GO as monotherapy or in combination with anthracyclines and/or nucleoside-analogue containing regimens or hypomethylating agents. For patients with APL, these included GO as monotherapy or in combination with all-trans retinoic acid and/or arsenic trioxide. Patients were permitted to re-enroll in treatment, and their data are summarized according to each enrollment treatment. Results: A total of 331 patients received GO either as monotherapy for R/R AML (adult [aged ≥18 years]: n=118; pediatric [aged The most frequently administered doses of GO in the monotherapy group were 9 mg/m2 (1 dose: n=21 [15%]; doses on ≥2 days: n=29 [21%]) and 3 mg/m2 (1 dose: n=10 [7%]; doses on ≥2 days: n=33 [24%]). Nearly all patients in the combination-therapy group received 3 mg/m2 (1 dose: n=96 [53%]; doses on ≥2 days: n=76 [42%]). GO 6 mg/m2 was the most frequently administered dose in the APL group (1 dose: n=3 [33%]; doses on ≥2 days: n=4 [44%]). Treatment was discontinued in 94 (68%), 71 (39%), and 3 (33%) patients in the monotherapy, combination-therapy, and APL groups, respectively. Common reasons for discontinuation included resistant disease (monotherapy: n=25 [18%]; combination therapy: n=16 [9%]; APL: n=1 [11%]), adverse events (AEs) not related to study drug (monotherapy: n=7 [5%]; combination therapy: n=3 [2%]; APL: n=1 [11%]), and AEs related to study drug (monotherapy: n=6 [4]%; combination therapy: n=4 [2%]; APL: n=0). All-causality grade 5 AEs were reported in 114 (34%) patients: 72 (52%), 40 (22%), and 2 (22%) in the monotherapy, combination-therapy, and APL groups, respectively. The most common grade 5 AEs (excluding disease progression and AML) were sepsis in the monotherapy group (n=7 [5%]; 4 treatment-related), respiratory failure in the combination-therapy group (n=5 [3%]; 1 treatment-related), and intracranial hemorrhage in the APL group (n=1 [11%], not treatment-related). Grade ≥3 treatment-related, treatment-emergent AEs (TEAEs) were reported for 84 (60%) patients in the monotherapy group, 102 (56%) patients in the combination-therapy group, and 7 (78%) patients in the APL group; hematologic TEAEs were most common, followed by hepatic TEAEs (Table). Possible hepatotoxicity was reported in 5 patients: 1 case each of veno-occlusive disease (VOD) and drug-induced liver injury in the monotherapy group and 2 cases of veno-occlusive liver disease (1 fatal) and 1 case of VOD in the combination-therapy group. Conclusions: GO was generally well tolerated; only a small proportion ( Disclosures Wang: Jazz: Speakers Bureau; Pfizer: Consultancy, Membership on an entity's Board of Directors or advisory committees; Amgen: Consultancy; Amgen: Consultancy; Jazz: Speakers Bureau; Novartis: Speakers Bureau; Pfizer: Consultancy, Membership on an entity's Board of Directors or advisory committees; Novartis: Speakers Bureau; Abbvie: Consultancy, Membership on an entity's Board of Directors or advisory committees; Abbvie: Consultancy, Membership on an entity's Board of Directors or advisory committees. Chirnomas:Pfizer Inc: Employment, Equity Ownership. Fazal:Novartis: Consultancy, Membership on an entity's Board of Directors or advisory committees; Jazz: Membership on an entity's Board of Directors or advisory committees; Pfizer: Speakers Bureau. Lin:Jazz Pharmaceuticals: Honoraria. Nand:Pfizer: Honoraria. Pierce:Pfizer Inc: Employment, Equity Ownership. Shami:JSK Therapeutics: Employment, Equity Ownership, Membership on an entity's Board of Directors or advisory committees; Lone Star Biotherapies: Equity Ownership; Baston Biologics Company: Membership on an entity's Board of Directors or advisory committees; Pfizer: Consultancy. Vermette:Pfizer: Employment, Equity Ownership. Abboud:Agios: Honoraria; Jazz: Honoraria, Speakers Bureau.

CPX-351, a dual-drug liposomal encapsulation of cytarabine and daunorubicin at a synergistic 5:1 molar drug ratio, achieved superior efficacy compared with conventional chemotherapy in older adults with newly diagnosed, high-risk/secondary acute myeloid leukemia (AML) in phase 2 and 3 studies. Prior to CPX-351 commercialization, an expanded access program (EAP) provided CPX-351 access for this population in the United States. In this phase 4, single-arm, open-label study (NCT02533115), 52 patients were treated with CPX-351 for 1-2 induction cycles and ≤4 consolidation cycles. The primary endpoint was safety. The most common serious adverse events were febrile neutropenia (19%), pneumonia (10%), and infection (8%). The 30- and 60-d mortality rates were 0% and 6%, respectively. Remission was achieved by 44% of patients; 90% of patients were alive at study completion. Overall, these results support outcomes from prior studies and the use of CPX-351 in older adults with newly diagnosed, high-risk/secondary AML.

Surveillance scans after autologous stem cell transplant (auto-HCT) for patients with relapsed/refractory (RR) diffuse large B Cell lymphoma (DLBCL) have no proven survival benefit. We studied survival differences among patients with RR DLBCL post auto-HCT whose recurrences were detected clinically versus with routine surveillance imaging. Among the 139 patients with RR DLBCL that underwent auto-HCT from 2000 to 2014 at our institution, 37 relapsed: 21 clinical and 16 radiological. The median time to progression was 167 days for the clinical cohort and 565 days for the radiological cohort (p = 0.03), and median overall survival (OS) was 587 days and not reached, respectively (p = 0.006). Most patients with relapsed DLBCL after auto-HCT were diagnosed clinically and were likely to be detected earlier and have a shorter OS. Relapse in patients with aggressive disease will likely be detected when clinically apparent, and the outcome of these patients is independent of the way the relapse is diagnosed. Thus, universal scanning after auto-HCT appears to have little benefit. Keywords: DLBCL, Surveillance, Relapse, Auto-HCT

Combretastatin A1 (OXi4503) is a dual-function drug with vascular disrupting and cytotoxic properties that has exhibited single-agent anti-leukemia activity in murine xenograft models of acute myeloid leukemia (AML) and in a prior Phase 1A clinical study for relapsed/refractory (R/R) AML. The purpose of the present multicenter Phase 1B study was to define the maximum tolerated dose (MTD) and safety profile of OXi4503 and cytarabine (ARA-C) administered in combination (OXA). At four centers, 29 patients with R/R AML or myelodysplastic syndrome (MDS) were treated with OXA. The most common grade 3/4 treatment-emergent adverse events (AEs) were febrile neutropenia (28%), hypertension (17%), thrombocytopenia (17%), and anemia (14%). There were no treatment-emergent grade 5 AEs. Drug-related serious adverse events (SAEs) developed in 4/29 patients (14%) and included febrile neutropenia (N = 2), pneumonia/acute respiratory failure (N = 1), and hypotension (N = 1). 9.76 mg/m2 was defined as the MTD of OXi4503 when administered in combination with 1 g/m2 ARA-C. In 26 evaluable AML patients, there were 2 complete remissions (CR), 2 complete remissions with incomplete count recovery (CRi) and one partial response (PR), for an overall response rate (ORR) of 19%. The median overall survival (OS) time for the four patients who achieved a CR/CRi was 528 days (95% CI: 434&ndash, NA), which was significantly longer than the median OS time of 113 days (95% CI: 77&ndash, 172) for the remaining 22 patients who did not achieve a CR/CRi (Log Rank Chi Square = 11.8, p-value = 0.0006). The safety and early evidence of efficacy of the OXA regimen in R/R AML patients warrant further investigation in a Phase 2 clinical study.

Background: Surveillance scans performed after autologous stem cell transplant (auto-HCT) for patients with Hodgkin disease (HD) have no proven survival benefit. Methods: We studied survival differences among patients with HD after auto-HCT whose recurrences were detected on clinical history and exam, versus those detected on routine surveillance scan. Results: Among the 98 patients with HD that underwent auto-HCT from 2000 to 2014 at our institution, 30 relapsed, of which 21 were detected radiologically and 9 clinically. There were no statistically significant differences in patient characteristics between the 2 groups. The median time to progression was 118 days for the clinical cohort and 284 days for the radiological cohort (p = 0.05). Median overall survival (OS) was 728 days for the clinical cohort, and was not reached for the radiological cohort (p = 0.02). Discussion: In our review, most patients with HD after auto-HCT were diagnosed radiologically. Patients whose relapse was diagnosed clinically were likely to be detected earlier and have a shorter OS. Patients with aggressive disease may be detected when clinically relevant, regardless of scanning. Routine scanning may not be necessary in the majority of patients with HD following auto-HCT.

APVO436 is a recombinant T-cell engaging humanized bispecific antibody designed to redirect host T-cell cytotoxicity in an MHC-independent manner to CD123-expressing blast cells from patients with hematologic malignancies. We evaluated the risk, severity, and biomarkers of treatment-emergent cytokine release syndrome (CRS) in patients with relapsed/refractory (R/R) acute myeloid leukemia (AML) or myelodysplastic syndrome (MDS) who received APVO436 during the dose escalation phase of a Phase 1B study (ClinicalTrials.gov identifier: NCT03647800). A total of 46 R/R AML/MDS patients received single agent APVO436 as weekly intravenous infusions at 10 different dose levels, ranging from 0.3 mcg to 60 mcg. CRS was the 7th th most common AE after pyrexia, diarrhea, infusion related reaction, peripheral edema, fatigue, and anemia affecting 10 (21.7%) of the 46 patients. Grade 3-4 CRS was the 6 th most common Grade ≥3 AE following febrile neutropenia, anemia, hyperglycemia, decreased platelet count, and sepsis occurring in 4 of the 46 patients (8.7%) treated with APVO436 in Study 5001 regardless of any relationship with the study drug APVO436. CRS was reported as an SAE in 7 (70%) of the 10 patients who developed CRS. CRS lead to dose interruptions in 4 patients, dose reduction in 1 patient, and permanent discontinuation of the study drug in 1 patient. Only 2 of the 46 patients experienced DLT and it was related to CRS in both patients. One patient treated in Cohort 4 who developed grade 2 CRS died due to complications from acute renal failure. Notwithstanding the fact that it is a potentially life-threatening complication, CRS did not significantly affect the overall survival outcome of the safety population (Figure 1). The average survival times were 169.1±42.1 days for patients who developed CRS and 173.9±27.2 days for the remainder of patients (P=0.9) (Table 1). The median survival was 188 days for patients with CRS and 151 days for those without CRS (Log-rank C 2 = 0.042, P=0.7) (Figure 1). Premedication with steroids (Dexamethasone) did not eliminate the risk of CRS. Of 4 patients who developed Grade ≥3 CRS, 2 had received steroid prophylaxis. Notably, CRS did not show an apparent dose-relationship. The average dose levels were 0.28±0.21 (Median: 0.19) µg/kg for those patients who developed CRS and 0.28±0.27 (Median: 0.20) µg/kg for those who did not develop CRS (P=0.97). There was a borderline significant age difference between patients who did versus patients who did not develop CRS (72.9±1.6 years [Median 73.5 years] vs. 63.3±2.3 years [Median: 65.0 years] (P=0.04). Diagnosis, dose level, gender, race, obesity, or baseline hematologic parameters in peripheral blood did not predict the risk of CRS (Table 1). There was a statistically insignificant (P=0.1) trend toward higher absolute lymphocyte count (ALC) for patients who experienced CRS. Patients with a higher leukemia burden, as determined by higher total WBC, higher percentage of blasts in bone marrow, or higher percentage of blasts in peripheral blood did not have a higher incidence of CRS. Cytokine profiling in select patients who developed Grade 2-4 CRS after APVO436 infusion indicates that the predominant cytokine in this inflammatory cytokine response is IL-6: Within 1-2 days following the first dose of APVO436, the mean serum IL-6 concentration was elevated 145-fold over baseline (755 vs 5.2) and at the end of one week it was still elevated 83-fold over baseline. APVO436-associated CRS was generally manageable with standard of care and in most cases it resolved rapidly with the administration of tocilizumab at standard doses combined with dexamethasone. APVO436-related CRS was not required for clinically meaningful responses in R/R AML patients, and it did not affect their survival outcome. Notably patients who developed CRS after APVO436 therapy were not more or less likely to have a favorable response. Among 8 patients with favorable responses, 4 experienced a CRS and 4 did not. APVO436-related CRS was not required for clinically meaningful responses in R/R AML patients, and it did not affect the survival outcome. Prolonged stabilization of disease, partial remissions and complete remissions were achieved in both patients who experienced CRS as well as patients who did not experience CRS after APVO436 infusions. Figure 1 Figure 1. Disclosures Lin: AbbVie, Aptevo Therapeutics, Astellas Pharma, Bio-Path Holdings, Celgene, Celyad, Genentech-Roche, Gilead Sciences, Incyte, Jazz Pharmaceuticals, Novartis, Ono Pharmaceutical, Pfizer, Prescient Therapeutics, Seattle Genetics, Tolero, Trovagene: Research Funding. Watts: Takeda: Consultancy, Research Funding; Genentech: Consultancy; Rafael Pharma: Consultancy; Celgene/BMS: Consultancy. Mims: Kura Oncology: Consultancy; Genentech: Consultancy; Abbvie: Consultancy; Syndax Pharmaceuticals: Consultancy; BMS: Consultancy; Jazz Pharmaceuticals: Consultancy; Daiichi-Saynko: Consultancy; Glycomemetics: Research Funding; Leukemia and Lymphoma Society: Consultancy; Aptevo: Research Funding; Xencor: Research Funding. Patel: Peerview: Honoraria; BMS-Celgene, Agios: Membership on an entity's Board of Directors or advisory committees; Aptevo Therapeutics: Research Funding. Shami: Chimerix: Research Funding; BMS: Consultancy; Gilead: Consultancy; Takeda: Consultancy; Chimerix: Research Funding; Bastion Biologics: Consultancy, Membership on an entity's Board of Directors or advisory committees; JSK Therapeutics: Consultancy, Current holder of individual stocks in a privately-held company, Membership on an entity's Board of Directors or advisory committees; Amgen: Research Funding; Aptevo: Research Funding. Cull: Aptevo: Research Funding. Cogle: Celgene: Membership on an entity's Board of Directors or advisory committees; Aptevo therapeutics: Research Funding. Lee: oncotelic therapeutics: Current equity holder in publicly-traded company; Aptevo therapeutics: Consultancy. Uckun: oncotelic therapeutics: Current equity holder in publicly-traded company; Aptevo therapeutics: Consultancy; Reven Pharmaceuticals (Reven LLC): Consultancy, Membership on an entity's Board of Directors or advisory committees.

Background: About two-thirds of AML patients harbor mutations in signaling and kinase pathways (e.g., FLT3, KRAS, NRAS, PTPN11, NF1, KIT), which utilize the growth factor receptor bound protein-2 (Grb2) to induce AML progression. Prexigebersen (BP1001), a liposome-incorporated Grb2 antisense oligonucleotide that inhibits Grb2 expression, suppresses cancer growth and survival. A Phase I/IB single center study (Ohanian, Lancet Haematol 2018) in relapsed/refractory AML patients demonstrated BP1001 safety up to 90 mg/m 2 and demonstrated CR/CRi in 3 of 6 relapsed/refractory AML patients treated with BP1001 + low dose cytarabine combination in the Phase IB portion. Preclinical studies indicated that BP1001 enhanced the inhibitory effects of decitabine (DAC), or DAC + venetoclax (VEN) against AML cells. Thus, we designed a clinical trial with three treatment arms: (1) BP1001 + DAC + VEN for newly diagnosed AML, (2) BP1001 + DAC + VEN for relapsed/refractory AML, (3) BP1001 + DAC for relapsed/refractory AML patients who are VEN-resistant or -intolerant [ClinicalTrials.gov Identifier: NCT02781883]. The study was amended to obtain safety run-in data for patients treated with BP1001 + DAC first before proceeding to safety run-in for patients treated with BP1001 + DAC + VEN. Here we report the safety run-in and efficacy data of AML patients treated with BP1001 + DAC or BP1001 + DAC + VEN. Methods: This is a multi-center open-label, Phase II study in newly diagnosed and relapsed/refractory AML patients to determine the safety and preliminary efficacy of BP1001 (given at 60 mg/m 2 over 2-3 h twice weekly for a total of 8 doses over a 28-day cycle) in combination with DAC (20 mg/m 2, once daily for 5 days) or in combination with DAC and VEN (400 mg, once daily). Eligible patients were considered unsuitable for or refused intensive chemotherapy and had ECOG performance status of 0-2. Patients treated with at least 1 cycle of therapy were evaluable for safety run-in. Results: Between April 2018 and May 2020, 6 patients (4 male: 67%) with median age 72 years (range, 51 - 76) were treated with at least 1 cycle of BP1001 + DAC combination therapy. Four patients (67%) had de novo AML and two (33%) had secondary AML. All patients in this cohort were considered high risk due to having either adverse risk status by ELN (n=5) or treated secondary AML (n=1) (transformed from myelodysplastic syndrome/myeloproliferative neoplasm after failing 4 lines of prior therapy). Adverse events (AEs) were generally consistent with those expected with DAC and/or AML and included diarrhea (67%), fatigue (50%), constipation (50%), nausea (50%), dyspnea (50%), hypoxia (50%), hypotension (50%) and pain in extremity (50%). The most frequent serious AE (SAE) was bacteremia (33%). Two de novo patients (33%) achieved a CRi and 1 treated secondary AML patient (17%) achieved a PR. Patients received a median of 2.5 cycles of therapy (range, 1 - 6); median duration of follow-up was 140 days (range, 72 - 678). Since May 2020, 6 patients (2 male: 33%) with median age 61 years (range, 44 - 81) were treated with at least 1 cycle of BP1001 + DAC + VEN combination therapy. Two (33%) had de novo AML, and four (67%) were relapsed/refractory. All patients in this cohort were adverse-risk by ELN (n=2) or relapsed/refractory (n=4). AEs were generally as expected with DAC, VEN and/or AML, including fatigue (67%), diarrhea (67%), constipation (67%), decreased appetite (67%), hypokalemia (67%), hypocalcemia (50%), edema peripheral (50%), asthenia (50%), nausea (50%), abdominal pain (50%), dysphagia (50%), hypotension (50%) and febrile neutropenia (50%). The most frequent SAEs were sepsis (33%) and febrile neutropenia (50%). Four patients (67%) achieved a CR/CRi/MLFS (n=1/2/1) and 1 (17%) achieved a PR. Of these patients, 3 were relapsed/refractory (1 CR/1 CRi/1 MLFS) and two were de novo (1 CRi/1 PR). Patients received a median of 4 cycles of therapy (range, 1 - 9); median duration of follow-up was 177 days (range, 113 - 318). Conclusions: BP1001-based combination therapy has been safely administered to high-risk and relapsed/refractory AML patients who were considered unsuitable for standard chemotherapy. Preliminary data showed the combination treatment of BP1001 + DAC or BP1001 + DAC + VEN was well-tolerated, with encouraging efficacy signals. The study will continue enrollment across all three cohorts. Drug dosing for the study will proceed as planned. Figure 1 Figure 1. Disclosures Lin: AbbVie, Aptevo Therapeutics, Astellas Pharma, Bio-Path Holdings, Celgene, Celyad, Genentech-Roche, Gilead Sciences, Incyte, Jazz Pharmaceuticals, Novartis, Ono Pharmaceutical, Pfizer, Prescient Therapeutics, Seattle Genetics, Tolero, Trovagene: Research Funding. Ritchie: Abbvie: Consultancy, Honoraria; Takeda: Consultancy, Honoraria; Incyte: Consultancy, Honoraria, Speakers Bureau; ARIAD Pharmaceuticals: Ended employment in the past 24 months, Speakers Bureau; Novartis: Consultancy, Honoraria, Other: travel support, Research Funding, Speakers Bureau; Celgene/BMS: Consultancy, Other: travel support, Speakers Bureau; Astellas: Consultancy, Research Funding; Bristol Myers Squibb: Consultancy, Research Funding; NS Pharma: Research Funding; Protaganist: Consultancy, Honoraria; Jazz: Consultancy, Research Funding; Pfizer: Consultancy, Research Funding. Pemmaraju: Clearview Healthcare Partners: Consultancy; ASH Communications Committee: Membership on an entity's Board of Directors or advisory committees; Plexxicon: Other, Research Funding; MustangBio: Consultancy, Other; Roche Diagnostics: Consultancy; Springer Science + Business Media: Other; DAVA Oncology: Consultancy; Stemline Therapeutics, Inc.: Consultancy, Membership on an entity's Board of Directors or advisory committees, Other, Research Funding; Abbvie Pharmaceuticals: Consultancy, Membership on an entity's Board of Directors or advisory committees, Other, Research Funding; Celgene Corporation: Consultancy; LFB Biotechnologies: Consultancy; Protagonist Therapeutics, Inc.: Consultancy; HemOnc Times/Oncology Times: Membership on an entity's Board of Directors or advisory committees; Samus: Other, Research Funding; Daiichi Sankyo, Inc.: Other, Research Funding; Novartis Pharmaceuticals: Consultancy, Other: Research Support, Research Funding; Affymetrix: Consultancy, Research Funding; Blueprint Medicines: Consultancy; Cellectis S.A. ADR: Other, Research Funding; Aptitude Health: Consultancy; CareDx, Inc.: Consultancy; Dan's House of Hope: Membership on an entity's Board of Directors or advisory committees; Sager Strong Foundation: Other; ASCO Leukemia Advisory Panel: Membership on an entity's Board of Directors or advisory committees; Incyte: Consultancy; Bristol-Myers Squibb Co.: Consultancy; ImmunoGen, Inc: Consultancy; Pacylex Pharmaceuticals: Consultancy. Borthakur: Ryvu: Research Funding; Novartis: Consultancy, Membership on an entity's Board of Directors or advisory committees; University of Texas MD Anderson Cancer Center: Current Employment; Astex: Research Funding; Protagonist: Consultancy; ArgenX: Membership on an entity's Board of Directors or advisory committees; GSK: Consultancy; Takeda: Membership on an entity's Board of Directors or advisory committees. Tari Ashizawa: Bio-Path Holdings, Inc.: Current Employment, Current equity holder in publicly-traded company, Membership on an entity's Board of Directors or advisory committees. Kantarjian: Immunogen: Research Funding; Ipsen Pharmaceuticals: Honoraria; AbbVie: Honoraria, Research Funding; Amgen: Honoraria, Research Funding; Daiichi-Sankyo: Research Funding; Aptitude Health: Honoraria; Precision Biosciences: Honoraria; Novartis: Honoraria, Research Funding; Taiho Pharmaceutical Canada: Honoraria; NOVA Research: Honoraria; Astra Zeneca: Honoraria; Ascentage: Research Funding; BMS: Research Funding; Astellas Health: Honoraria; Pfizer: Honoraria, Research Funding; Jazz: Research Funding; KAHR Medical Ltd: Honoraria. Cortes: Novartis: Consultancy, Research Funding; Sun Pharma: Consultancy, Research Funding; Takeda: Consultancy, Research Funding; Bristol Myers Squibb, Daiichi Sankyo, Jazz Pharmaceuticals, Astellas, Novartis, Pfizer, Takeda, BioPath Holdings, Incyte: Consultancy, Research Funding; Bio-Path Holdings, Inc.: Consultancy, Membership on an entity's Board of Directors or advisory committees; Pfizer: Consultancy, Research Funding. Roboz: Amgen: Consultancy; MEI Pharma - IDMC Chair: Consultancy; Bayer: Consultancy; AstraZeneca: Consultancy; AbbVie: Consultancy; Celgene: Consultancy; Blueprint Medicines: Consultancy; Glaxo SmithKline: Consultancy; Agios: Consultancy; Helsinn: Consultancy; Jazz: Consultancy; Janssen: Consultancy; Astex: Consultancy; Bristol Myers Squibb: Consultancy; Actinium: Consultancy; Jasper Therapeutics: Consultancy; Novartis: Consultancy; Otsuka: Consultancy; Mesoblast: Consultancy; Daiichi Sankyo: Consultancy; Astellas: Consultancy; Janssen: Research Funding; Pfizer: Consultancy; Roche/Genentech: Consultancy.

Background: CPX-351 (United States: Vyxeos ®; Europe: Vyxeos ® Liposomal), a dual-drug liposomal encapsulation of daunorubicin and cytarabine in a synergistic 1:5 molar ratio, is approved for the treatment of newly diagnosed therapy-related acute myeloid leukemia (AML) or AML with myelodysplasia-related changes in adults and pediatric patients aged ≥1 year in the United States and in adults in the European Union. In a phase 3 study in adults aged 60 to 75 years with newly diagnosed high-risk/secondary AML who were eligible for intensive chemotherapy (IC), after 5 years of follow-up CPX-351 significantly improved median overall survival versus conventional 7+3 cytarabine/daunorubicin, with a comparable safety profile. Venetoclax (VEN; BCL-2 inhibitor) + low-dose cytarabine has demonstrated efficacy in unfit patients with AML, and preclinical data support a rationale for combining CPX-351 + VEN. This study evaluates the safety and efficacy of lower-dose CPX-351 + VEN in adults with newly diagnosed AML who are considered unfit to receive IC. Methods: This is an ongoing, open-label, multicenter, phase 1b study (NCT04038437) to determine the recommended phase 2 dose (RP2D) and evaluate the safety and efficacy of lower-dose CPX-351 + VEN in adults with newly diagnosed AML who are considered unfit to receive IC. The dose-exploration phase (3+3 design; n ≤24) evaluated multiple dose levels of CPX-351 on Days 1 and 3 + VEN 400 mg on Days 2 to 21 of each cycle to determine the RP2D. Patients who achieve at least partial remission after 1 or 2 cycles may receive up to 4 similar cycles of CPX-351 + VEN. During the expansion phase, 20 additional patients will receive CPX-351 + VEN at the RP2D. Patients are assessed for response by morphology and measurable residual disease (MRD) testing and are monitored for safety and survival. Results: This preliminary analysis includes data from 14 enrolled patients. Patients were considered unfit for IC based on age ≥75 years (n = 7 [50%]) or health (aged 18 to 74 years with an EGOC performance status of 2 or 3 [n = 3 (21%)] and/or comorbidities [n = 5 (36%]). Overall, 50% of the patients had poor-risk cytogenetics, 64% were male, 71% had a diagnosis of de novo AML, and 29% had mutated TP53 (Table 1). Four patients received dose level 1 (CPX-351 20 units/m 2 [daunorubicin 8.8 mg/m 2 + cytarabine 20 mg/m 2] + VEN), with no dose-limiting toxicities (DLTs) observed in the 3 evaluable patients. Seven patients were subsequently enrolled in dose level 2 (CPX-351 40 units/m 2 [daunorubicin 17.6 mg/m 2 + cytarabine 40 mg/m 2] + VEN), with 6 patients evaluable for DLTs. At dose level 2, 1 patient experienced 2 DLTs (grade 3 tumor lysis syndrome and liver injury); review of the overall safety profile led to a protocol amendment that permitted de-escalation to dose level 1b (CPX-351 30 units/m 2 [daunorubicin 13.2 mg/m 2 + cytarabine 30 mg/m 2] + VEN). Three patients received dose level 1b with no DLTs and a safety profile comparable to dose level 1. Together, these data established dose level 1b as the RP2D. The most common nonhematologic treatment-emergent adverse events (TEAEs) were gastrointestinal events and peripheral edema (Table 2). The majority (86%) of patients experienced a grade ≥3 TEAE, primarily myelosuppression; the only nonhematologic grade ≥3 TEAE in >10% of patients was tumor lysis syndrome (14%). No patient experienced early mortality by Day 30; the mortality rate at Day 60 was 7% due to 1 death in the dose level 1 cohort (myocardial infarction considered unrelated to treatment). Among the 12 patients evaluable for efficacy across dose levels, 8 (67%) achieved a best response of complete remission (CR): 3/4 (75%) in dose level 1, 3/5 (60%) in dose level 2, and 2/3 (67%) in dose level 1b. All patients who achieved a best response of CR entered into either CR or CR with incomplete neutrophil or platelet recovery after the first treatment cycle. Confirmation of MRD status is currently ongoing. Conclusions: Preliminary results from this ongoing phase 1b study established a RP2D of CPX-351 30 units/m 2 on Days 1 and 3 + VEN 400 mg on Days 2 to 21 in adults with newly diagnosed AML who were considered unfit to receive IC. The combination of lower-dose CPX-351 + VEN was generally well tolerated and demonstrated promising initial efficacy, with achievement of CR in the majority of patients. This study is ongoing and enrolling 20 additional patients to further evaluate the RP2D. Figure 1 Figure 1. Disclosures Uy: Novartis: Consultancy; GlaxoSmithKline: Consultancy; Agios: Consultancy; AbbVie: Consultancy; Macrogenics: Research Funding; Astellas: Honoraria, Speakers Bureau; Genentech: Consultancy; Jazz: Consultancy. Pullarkat: AbbVie, Amgen, Genentech, Jazz Pharmaceuticals, Novartis, Pfizer, and Servier: Membership on an entity's Board of Directors or advisory committees; Amgen, Dova, and Novartis: Consultancy, Honoraria. Baratam: Celgene/Bristol Myers Squibb: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau. Stuart: Sunesis Pharmaceuticals: Consultancy; Sunesis Pharmaceuticals: Honoraria; Sunesis Pharmaceuticals: Other: Travel Support; Agios, Astellas Pharma, Bayer AG, Incyte, Jazz Pharmaceuticals, Ono Pharmaceuticals, and Sunesis Pharmaceuticals: Research Funding. Faderl: Jazz Pharmaceuticals: Current Employment, Current equity holder in publicly-traded company. Chandrasekaran: Jazz Pharmaceuticals: Current Employment, Current equity holder in publicly-traded company. Wang: Jazz Pharmaceuticals: Current Employment, Current equity holder in publicly-traded company. Chakravarthy: Jazz Pharmaceuticals: Current Employment, Current equity holder in publicly-traded company. Cheung: Jazz Pharmaceuticals: Current Employment, Current equity holder in publicly-traded company. Lin: AbbVie, Aptevo Therapeutics, Astellas Pharma, Bio-Path Holdings, Celgene, Celyad, Genentech-Roche, Gilead Sciences, Incyte, Jazz Pharmaceuticals, Novartis, Ono Pharmaceutical, Pfizer, Prescient Therapeutics, Seattle Genetics, Tolero, Trovagene: Research Funding. OffLabel Disclosure: combination of CPX-351 [Vyxeos] and venetoclax in adults with previously untreated AML

Background: IVO is an oral potent inhibitor of mutated IDH1 (IDH1m) enzyme, recently approved for the treatment (Tx) of ND adult patients (pts) with IDH1m AML ≥75 years old or with comorbidities precluding use of intensive induction chemotherapy, and adult pts with relapsed or refractory AML. In this Phase 2 sub-study of the Beat AML Master Trial, we evaluated the efficacy of IVO + AZA combination Tx in ND pts aged ≥60 years with IDH1m AML (ClinicalTrials.gov: NCT03013998) Methods: This open-label multicenter (16 sites / 9 enrolling) combination Tx study enrolled ND pts with R132 mIDH1 AML, utilizing the modified minimax Simon's 2-stage Phase 2 design. Pts received IVO + AZA for 6 cycles in the absence of disease progression (PD), unacceptable toxicity or stem cell transplant. Pts who achieved complete remission (CR)/complete remission with hematologic improvement (CRh)/complete remission with incomplete hematologic recovery (CRi) continued IVO + AZA for a total of 12 cycles, then IVO monotherapy until PD. Pts without CR/CRh/CRi after 6 cycles continued IVO + AZA if they demonstrated Tx benefit, as defined in Figure 1. Key eligibility included ND IDH1 R132 mutated AML pts aged ≥60 years and ECOG performance status 0 - 2 (Karnofsky ≥60). All pts received IVO 500 mg/day orally in continuous 28-day cycles + AZA 75 mg/m2 IV or SC on days 1-7 every 28 days. The primary endpoint was CR+CRh+CRi rate after 6 cycles of Tx. Response was assessed using modified 2017 ELN AML criteria. The modified minimax Simon's 2-stage design required 40 pts and tested the null hypothesis that the CR/CRh/CRi rate equaled 25% vs the alternative of 50% (one-sided alpha = 0.025, power 90%). Stage 1 required >5/16 responses for continued enrollment. Even though these criteria were met, the sponsor decided to discontinue the trial on 12/12/2019. Here we report the final primary endpoint results. Data were frozen 02/03/2021. Results: Between 07/2018 and 11/2019, 19 patients were enrolled with IDH1m AML; 18 started IVO + AZA Tx and are included in the analyses. At data freeze, 5 pts had died and 7 pts still on Tx were offered standard of care IVO. Median age of the pts was 75 years, 50% were ≥75 years, 61% were female and 89% were White (Table 1). The most common reasons for Tx discontinuation were trial discontinued by sponsor (7 or 39%), stem cell transplant (4 or 22%), and PD (3 or 17%). A total of 13 pts achieved CR/CRh/CRi (72%) by up to 6 cycles of Tx (Table 2 & Figure 2). Over the entire study period, 14 pts achieved CR/CRh/CRi (78%) with 8 CR (44%), 3 CRh (17%) and 3 CRi (17%). No deaths occurred within the first 60 days of Tx. After a median follow up of 19.8 months (mos), Page 2 median response duration was not reached, with 12-mos disease-free survival rate of 69%; also, median OS was not reached, with 12- and 18-mos OS rates of 100% and 73%, respectively. The median (range) time on Tx was 12 mos ( Conclusions: In ND pts with IDH1m AML and ≥60 years of age, IVO + AZA Tx was associated with a high CR/CRh/CRi rate, no early deaths (60 days) and a 1-year OS of 100%. IVO + AZA was acceptably tolerated and no unexpected toxicities occurred. Most common unique toxicities of IVO observed during the study were differentiation syndrome and QTc prolongation; these led to Tx discontinuation in only 1 pt. CR/CRh/CRi rate obtained with IVO +AZA is higher than that previously reported in studies with the individual agents or intensive chemotherapy approaches, suggesting a synergistic effect. Our overall response rate is similar to that reported recently for IVO + AZA in older ND IDH1 mutant AML pts, despite not including pts with morphologic leukemia-free state and partial remission. Based on these results, a global Phase 3 evaluation of IVO or placebo plus AZA is ongoing (NCT03173248). Figure 1 Figure 1. Disclosures Patel: BMS-Celgene, Agios: Membership on an entity's Board of Directors or advisory committees; Aptevo Therapeutics: Research Funding; Peerview: Honoraria. Ruppert: Telios Pharma: Consultancy. Borate: Daiichi-Sankyo: Membership on an entity's Board of Directors or advisory committees; Pfizer: Membership on an entity's Board of Directors or advisory committees, Research Funding; Takeda: Membership on an entity's Board of Directors or advisory committees; Genentech: Membership on an entity's Board of Directors or advisory committees, Other: Advisory Board; AbbVie: Membership on an entity's Board of Directors or advisory committees, Research Funding; Novartis: Membership on an entity's Board of Directors or advisory committees, Research Funding; Jazz Pharma: Research Funding; Blueprint Medicine: Membership on an entity's Board of Directors or advisory committees; Astellas: Membership on an entity's Board of Directors or advisory committees; incyte: Membership on an entity's Board of Directors or advisory committees, Research Funding; Rampal: Membership on an entity's Board of Directors or advisory committees; Galecto, Inc.: Consultancy; Promedior: Consultancy. Stein: Syros Pharmaceuticals, Inc.: Consultancy; Daiichi Sankyo: Consultancy; PinotBio: Consultancy; Celgene: Consultancy; Bristol Myers Squibb: Consultancy; Jazz Pharmaceuticals: Consultancy; Foghorn Therapeutics: Consultancy; Blueprint Medicines: Consultancy; Gilead Sciences, Inc.: Consultancy; Abbvie: Consultancy; Janssen Pharmaceuticals: Consultancy; Genentech: Consultancy; Agios Pharmaceuticals, Inc: Consultancy; Novartis: Consultancy; Astellas: Consultancy; Syndax Pharmaceuticals: Consultancy. Stock: Pfizer: Consultancy, Honoraria, Research Funding; amgen: Honoraria; agios: Honoraria; jazz: Honoraria; kura: Honoraria; kite: Honoraria; morphosys: Honoraria; servier: Honoraria; syndax: Consultancy, Honoraria; Pluristeem: Consultancy, Honoraria. Kovacsovics: AbbVie: Research Funding; Janssen Pharmaceuticals: Research Funding; Amgen Inc.: Research Funding; Novartis: Research Funding; Stemline: Honoraria; Jazz Pharmaceutials: Honoraria. Blum: Leukemia and Lymphoma Society: Research Funding; Nkarta: Research Funding; Celyad Oncology: Research Funding; Syndax: Honoraria; Xencor: Research Funding; Abbvie: Honoraria; Forma Therapeutics: Research Funding; AmerisourceBergen: Honoraria. Arellano: KITE Pharma, Inc: Consultancy; Syndax Pharmaceuticals, Inc: Consultancy. Schiller: Sangamo: Research Funding; Takeda: Research Funding; Ono-UK: Consultancy, Research Funding; Gamida Cell Ltd.: Research Funding; Tolero: Research Funding; Samus: Research Funding; Karyopharm: Research Funding; BMS/Celgene: Consultancy, Current equity holder in publicly-traded company, Research Funding, Speakers Bureau; Amgen: Consultancy, Current equity holder in publicly-traded company, Honoraria, Research Funding, Speakers Bureau; Bio: Research Funding; Mateon: Research Funding; Genentech-Roche: Research Funding; FujiFilm: Research Funding; Agios: Consultancy, Research Funding, Speakers Bureau; Actinium Pharmaceuticals, Inc: Research Funding; Kite/Gilead: Honoraria, Research Funding, Speakers Bureau; Incyte: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding, Speakers Bureau; Arog: Research Funding; Delta-Fly: Research Funding; Celator: Research Funding; Forma: Research Funding; Astellas: Honoraria, Research Funding, Speakers Bureau; Stemline Therapeutics, Inc.: Honoraria, Research Funding, Speakers Bureau; Regimmune: Research Funding; PrECOG: Research Funding; Constellation Pharmaceuticals: Research Funding; Trovagene: Research Funding; Elevate: Research Funding; Deciphera: Research Funding; Actuate: Research Funding; Jazz: Consultancy, Honoraria, Research Funding, Speakers Bureau; Daiichi-Sankyo: Research Funding; Onconova: Research Funding; Geron: Research Funding; Novartis: Consultancy, Research Funding; Pfizer: Current equity holder in publicly-traded company, Research Funding; Abbvie: Research Funding; Sanofi: Honoraria, Research Funding, Speakers Bureau; Pharma: Consultancy; Johnson & Johnson: Current equity holder in publicly-traded company; Biomed Valley Discoveries: Research Funding; Eli Lilly: Research Funding; ASH foundation: Other: Chair-unpaid; Sellas: Research Funding; Ono: Consultancy; Incyte: Consultancy; Ariad: Research Funding; AstraZeneca: Consultancy; Kaiser Permanente: Consultancy; Cyclacel: Research Funding; MedImmune: Research Funding; Ambit: Research Funding; Leukemia & Lymphoma Society: Research Funding; Bluebird Bio: Research Funding; Boehringer-Ingleheim: Research Funding; Cellerant: Research Funding; CTI Biopharma: Research Funding; Janssen: Research Funding; Kura Oncology: Research Funding; Pharmacyclics: Honoraria, Speakers Bureau; Millennium: Research Funding; National Marrow Donor Program: Research Funding; NIH: Research Funding; Onyx: Research Funding; Pharmamar: Research Funding; UC Davis: Research Funding; UCSD: Research Funding; Evidera: Consultancy; NCI: Consultancy; Novartis: Speakers Bureau. Olin: Actinium: Honoraria; Abbvie: Honoraria; Amgen: Honoraria; Cellectis: Research Funding; Pfizer: Research Funding; Genentech: Research Funding; Daiichi Sankyo: Research Funding; Astellas: Honoraria, Research Funding. Foran: pfizer: Honoraria; gamida: Honoraria; servier: Honoraria; kura: Research Funding; abbvie: Research Funding; takeda: Research Funding; trillium: Research Funding; revolution medicine: Honoraria; novartis: Honoraria; certara: Honoraria; sanofi aventis: Honoraria; bms: Honoraria; syros: Honoraria; taiho: Honoraria; OncLive: Honoraria; actinium: Research Funding; aptose: Research Funding; boehringer ingelheim: Research Funding; h3bioscience: Research Funding; aprea: Research Funding; sellas: Research Funding; stemline: Research Funding. Litzow: Pluristem: Research Funding; Astellas: Research Funding; AbbVie: Research Funding; Jazz: Other: Advisory Board; Amgen: Research Funding; Actinium: Research Funding; Omeros: Other: Advisory Board; Biosight: Other: Data monitoring committee. Lin: AbbVie, Aptevo Therapeutics, Astellas Pharma, Bio-Path Holdings, Celgene, Celyad, Genentech-Roche, Gilead Sciences, Incyte, Jazz Pharmaceuticals, Novartis, Ono Pharmaceutical, Pfizer, Prescient Therapeutics, Seattle Genetics, Tolero, Trovagene: Research Funding. Foster: Agios: Consultancy; Daiichi Sankyo: Consultancy; Macrogenics: Consultancy; Rafael Pharmaceuticals: Research Funding; Macrogenics: Research Funding; Bellicum Pharmaceuticals: Research Funding. Cogle: Celgene: Membership on an entity's Board of Directors or advisory committees; Aptevo therapeutics: Research Funding. Vergilio: Roche: Current equity holder in publicly-traded company; Foundation Medicine: Current Employment. Gana: Bausch: Current holder of individual stocks in a privately-held company; The Leukemia & Lymphoma Society: Consultancy. Druker: The RUNX1 Research Program: Membership on an entity's Board of Directors or advisory committees; EnLiven: Consultancy, Research Funding; Amgen: Current equity holder in publicly-traded company, Membership on an entity's Board of Directors or advisory committees; Aptose Therapeutics: Consultancy, Current equity holder in publicly-traded company, Membership on an entity's Board of Directors or advisory committees; Blueprint Medicines: Consultancy, Current equity holder in publicly-traded company, Membership on an entity's Board of Directors or advisory committees; GRAIL: Current equity holder in publicly-traded company; Nemucore Medical Innovations, Inc.: Consultancy; Merck & Co: Patents & Royalties; Novartis Pharmaceuticals: Membership on an entity's Board of Directors or advisory committees, Patents & Royalties; Bristol-Myers Squibb: Research Funding; Cepheid: Consultancy, Membership on an entity's Board of Directors or advisory committees; Iterion Therapeutics: Membership on an entity's Board of Directors or advisory committees; Recludix Pharma, Inc.: Consultancy; Third Coast Therapeutics: Membership on an entity's Board of Directors or advisory committees; VB Therapeutics: Membership on an entity's Board of Directors or advisory committees; Aileron: Membership on an entity's Board of Directors or advisory committees; ALLCRON: Consultancy, Membership on an entity's Board of Directors or advisory committees; Pfizer: Research Funding; Vincerx Pharma: Current equity holder in publicly-traded company, Membership on an entity's Board of Directors or advisory committees; Vivid Biosciences: Membership on an entity's Board of Directors or advisory committees. Byrd: Vincerx Pharmaceuticals: Current equity holder in publicly-traded company, Membership on an entity's Board of Directors or advisory committees; Novartis, Trillium, Astellas, AstraZeneca, Pharmacyclics, Syndax: Consultancy, Honoraria; Newave: Membership on an entity's Board of Directors or advisory committees. Levine: QIAGEN: Membership on an entity's Board of Directors or advisory committees; Imago: Membership on an entity's Board of Directors or advisory committees; Ajax: Membership on an entity's Board of Directors or advisory committees; Mission Bio: Membership on an entity's Board of Directors or advisory committees; Zentalis: Membership on an entity's Board of Directors or advisory committees; Lilly: Honoraria; Celgene: Research Funding; Isoplexis: Membership on an entity's Board of Directors or advisory committees; Roche: Honoraria, Research Funding; Incyte: Consultancy; Janssen: Consultancy; Astellas: Consultancy; Morphosys: Consultancy; Gilead: Honoraria; Amgen: Honoraria; C4 Therapeutics: Membership on an entity's Board of Directors or advisory committees; Prelude: Membership on an entity's Board of Directors or advisory committees; Auron: Membership on an entity's Board of Directors or advisory committees. Mims: Leukemia and Lymphoma Society: Consultancy; Kura Oncology: Consultancy; Genentech: Consultancy; Abbvie: Consultancy; Syndax Pharmaceuticals: Consultancy; BMS: Consultancy; Aptevo: Research Funding; Xencor: Research Funding; Glycomemetics: Research Funding; Jazz Pharmaceuticals: Consultancy; Daiichi-Saynko: Consultancy. OffLabel Disclosure: IVO is an oral potent inhibitor of mutated IDH1 enzyme, recently approved for the treatment of ND adult patients with IDH1m AML âââ,¬Â°Ã,Â¥75 years old or with comorbidities precluding use of intensive induction chemotherapy, and adult pts with relapsed or refractory AML. The combination of AZA, a hypomethylating agent, and venetoclax, an oral BCL-2 inhibitor, is also FDA approved for newly diagnosed AML in adults 75 years or older, or who have comorbidities precluding intensive chemotherapy. This presentation will discuss the combination of IVO and AZA.

Features of central nervous system (CNS) involvement in acute myeloid leukemia (AML) are not well-defined. Unlike acute lymphoblastic leukemia, there are limited guidelines for the use of intrathecal chemotherapy with induction for AML, and institutional practices vary. Unfortunately, AML patients with CNS involvement often have worse outcomes compared to those without CNS involvement (Del Principe et al., 2018; Rozovski et al., 2015). It is important to better understand the incidence and predictive clinical and features of CNS involvement in AML to identify patients for diagnostic testing and intrathecal chemotherapy. This retrospective analysis evaluated the incidence and characteristics of CNS involvement in adult AML patients at our institution. CNS screening is recommended for AML patients with specific characteristics, including CNS symptoms, monocytic phenotype, FLT3-internal tandem duplication gene mutation, and hyperleukocytosis (>100,000 white blood cells per microliter). Treatment recommendations for CNS involvement include intrathecal methotrexate, intrathecal cytarabine, or a combination of both. In this IRB-approved retrospective study, medical records were analyzed from the University of Kansas Medical Center from years 2015-2020. Patients were selected by searching the electronic medical record for adult AML patients who received a diagnostic lumbar puncture. Characteristics of interest included presence of CNS symptoms, monocytic phenotype, FLT3 mutation, and hyperleukocytosis. Characteristics that prompted CNS screening were recorded for each patient. Additional data collection included next-generation sequencing (NGS), cytogenetic results, and whether CNS screening occurred during an initial diagnosis or during an AML relapse. Lastly, the number of intrathecal chemotherapy doses was recorded for each patient. The incidence of CNS involvement was determined by dividing the number of newly diagnosed AML CNS-positive patients by the total number of newly diagnosed AML patients. Screening detection rates were determined by dividing the number of CNS-positive patients with each characteristic by the total number that received a lumbar puncture. The percentage of CNS-positive patients with each characteristic was determined by dividing the number with each specific characteristic by the total number of CNS-positive patients. The number of intrathecal chemotherapy doses required for CNS clearance was determined using data only from patients that achieved CNS clearance. Forty-eight patients met current guidelines for CNS screening; 25 were CNS-positive and 23 were CNS-negative (overall screening detection rate of 52%). The incidence of CNS involvement among all newly diagnosed adult AML patients was 3.24%. Screening detection rates were 58% for patients with 3 characteristics, 60% for 2 characteristics, 45% for CNS symptoms, and 30% for monocytic phenotype. Not enough patients presented with the FLT3 mutation or hyperleukocytosis in isolation to calculate accurate detection rates. The CNS-positive group consisted of 28% with 3 characteristics, 24% with 2 characteristics, 20% with CNS symptoms, 12% with monocytic phenotype, 4% with FLT3 mutation, 4% with hyperleukocytosis, and 36% were screened during a relapse rather than at initial diagnosis. Two patients were CNS-positive without any of our characteristics of interest (screened due to extramedullary involvement at presentation and the other was screened as part of pre-transplant evaluation). Seventeen patients achieved CNS clearance with 41% requiring 1 dose of intrathecal chemotherapy, 35% requiring 2 doses, and 24% requiring more than 2 doses. NGS and cytogenetic results did not reveal any additional associations. This data indicates that current AML CNS screening guidelines appear to properly identify a patient population at risk for CNS involvement. At our institution, 52% of screened patients were CNS-positive. This analysis also revealed a diverse distribution of characteristics among AML patients with CNS involvement, and patients commonly presented with multiple risk factors. These results emphasize the need for ongoing research to further delineate CNS involvement risk factors in AML. This data will be used for current policy analysis at our institution and potentially prospective studies to better evaluate outcomes for AML patients with CNS involvement. Figure 1 Figure 1. Disclosures Lin: AbbVie, Aptevo Therapeutics, Astellas Pharma, Bio-Path Holdings, Celgene, Celyad, Genentech-Roche, Gilead Sciences, Incyte, Jazz Pharmaceuticals, Novartis, Ono Pharmaceutical, Pfizer, Prescient Therapeutics, Seattle Genetics, Tolero, Trovagene: Research Funding.

Background: GILT is an oral potent selective FLT3 kinase inhibitor approved for marketing for the treatment (Tx) of patients (pts) with relapsed/refractory FLT3 mutated (FLT3m) AML but efficacy in older ND FLT3m AML pts is unknown. Furthermore, FLT3m can be present as a dominant or subclone and impact of FLT3 inhibitor therapy in this setting is uncertain. Here we report the results of a Phase 2/1b sub-study of the Beat AML Master Trial to assess the efficacy of GILT monotherapy (GILTm) in ND FLT3m AML pts aged ≥60 years with high and low VAF and the subsequent response-driven addition of DEC Tx. (ClinicalTrials.gov NCT03013998) Methods: The study was an open-label multicenter (15 sites), 3-outcome, 2-stage Phase 2 design that assigned pts to either Dominant FLT3/Group 1 (GP1) or Non-Dominant FLT3/Group 2 (GP2) as shown in Figure 1. Key eligibility criteria included ND FLT3m AML pts with high and low VAF and/or ITD ratio, aged ≥60 years, and ECOG performance status 0-2. In the Phase 2 study, all pts received GILTm 120 mg/day on days 1 - 28. Pts without CR/CRi after cycle 2 were transferred to the Phase 1b study to receive GILT + DEC (Figure 1). Phase 1b study utilized a standard 3+3 design to evaluate the safety/tolerability of concurrent GILT + DEC. Pts received GILT (dose level 1 [DL1] = 80 mg/day or dose level 2 [DL2] = 120 mg/day on days 1-28) + DEC 20 mg/m 2 IV on days 1-10 or 1-5 every 28 days. Primary endpoint was CR+CRi rate (Phase 2). Response was assessed using modified 2017 ELN AML criteria. The non-dominant GP2 was stopped for futility, GP1 was stopped early to modify trial to include venetoclax. Results: Phase 2 - Between 9/10/2018 to 2/11/2020, 19 / 20 enrolled pts (GP1: n = 9; GP2: n = 10) received GILTm and were included in analyses. Baseline pt characteristics are shown in Table 1. Median (range) time on GILTm was 3 cycles (1 - 18) in GP1 and 1 cycle (1 - 9) in GP2. Most common reasons for discontinuing Tx were Tx failure (TF; 44%) and relapse (33%) in GP1 and TF (70%) and disease progression (PD; 20%) in GP2. Overall CR+CRi was achieved in 4 pts (44%) in GP1 and 1 pt (10%) in GP2. Response duration are shown in Table 2. After median follow-up of 14.3 months (mos) and 19 mos in GP1 and GP2, respectively, 1-year OS was 56% and 76%. Most common Grade ≥3 adverse events (AEs) were febrile neutropenia and colitis (each 25%) in GP1; anemia and low platelet count in GP2 (each 30%). Overall, 7 pts had 15 serious AEs (SAEs) and all SAEs occurred in GP1 pts; most common SAE was colitis (25%) and 1 pt (13%) had a Tx-related Grade 3 SAE of tumor lysis syndrome. In GP2, 1 pt (10%) had Tx-related Grade 2 AE of differentiation syndrome. In GP1, 2 pts died within 60 days of Tx and none in GP2. Phase1b - After up to 2 cycles of GILTm, 12 pts with no CR/CRi (GP1: n = 4; GP2: n = 8) were transferred to receive GILT + DEC (Figure 1). At the time of this report, 1 pt with CRh remained on Tx. Median total time on Tx (including GILTm) was 4 cycles and median time on GILT + DEC Tx was 3 cycles (Table 2). Most common reasons for discontinuing Tx were PD (33%) and TF (25%); and 2 pts (17%) stopped Tx due to an AE. Pts were treated with DL1 GILT + DEC (n = 3), then DL2 GILT + DEC (n = 9); only 1 pt had dose-limiting toxicity (DLT) at DL2 (Grade 3 hyperbilirubinemia and pneumonitis requiring steroid therapy), hence, DL2 GILT + DEC was considered the MTD. CR+CRi rate was 25% in 3 pts, all at DL2 (Table 2). After a median follow-up of 17.8 mos, the 1-year OS from start of GILT + DEC Tx was 57%. Most common Grade ≥3 Tx-related AEs were anemia, febrile neutropenia and low WBC count (each 22%). Overall, 6 pts had 12 SAEs; 1 pt with SAE of Grade 4 sepsis died. Three GILT-related SAEs occurred in 1 pt - Grade 3 hyperbilirubinemia, and pneumonitis and Grade 1 transaminases increased. One pt died within 30 days and a second within 60 days of Tx. No difference was observed in GILT pharmacokinetics (PK) with or without DEC, however steady state Ctrough values were 1.4 to 2.3-fold greater than in relapsed/refractory AML pts (Admiral trial). Conclusions: In ND pts ≥60 years old with dominant FLT3 AML, GILTm induced a high 44% CR+CRi rate and long median OS (21.7 mos). Pts with non-dominant FLT3 had low 10% CR+CRi rate. GILTm was generally safe and was associated with differentiation syndrome in 1 pt. Concurrent GILT + DEC was acceptably tolerated, only 1 pt had a DLT, and the MTD was 120 mg/day GILT + DEC. A subset of pts with no CR/CRi during GILTm achieved remission with addition of DEC. Based on these results, a triple combination Tx study with venetoclax is currently enrolling. Figure 1 Figure 1. Disclosures Traer: Genentech: Membership on an entity's Board of Directors or advisory committees; Schrodinger: Research Funding; Incyte: Research Funding; Abbvie: Consultancy, Membership on an entity's Board of Directors or advisory committees; Servier/Agios: Membership on an entity's Board of Directors or advisory committees; Astellas: Consultancy, Membership on an entity's Board of Directors or advisory committees; ImmunoGen: Membership on an entity's Board of Directors or advisory committees. Mims: Glycomemetics: Research Funding; Daiichi Sankyo: Consultancy, Research Funding; Aptevo: Research Funding; Leukemia and Lymphoma Society's Beat AML clinical study: Consultancy, Research Funding; Genentech: Consultancy; Xencor: Research Funding; Kartos Pharmaceuticals: Research Funding; Abbvie: Consultancy; BMS: Consultancy; Kura Oncology: Consultancy; Syndax Pharmaceuticals: Consultancy; BMS: Consultancy; Jazz Pharmaceuticals: Consultancy; Aptevo: Research Funding. Stein: Agios Pharmaceuticals, Inc: Consultancy; Novartis: Consultancy; Astellas: Consultancy; Syndax Pharmaceuticals: Consultancy; Daiichi Sankyo: Consultancy; Syros Pharmaceuticals, Inc.: Consultancy; PinotBio: Consultancy; Celgene: Consultancy; Bristol Myers Squibb: Consultancy; Jazz Pharmaceuticals: Consultancy; Foghorn Therapeutics: Consultancy; Blueprint Medicines: Consultancy; Gilead Sciences, Inc.: Consultancy; Abbvie: Consultancy; Janssen Pharmaceuticals: Consultancy; Genentech: Consultancy. Stock: Pfizer: Consultancy, Honoraria, Research Funding; amgen: Honoraria; agios: Honoraria; jazz: Honoraria; kura: Honoraria; kite: Honoraria; morphosys: Honoraria; servier: Honoraria; syndax: Consultancy, Honoraria; Pluristeem: Consultancy, Honoraria. Kovacsovics: AbbVie: Research Funding; Jazz Pharmaceutials: Honoraria; Janssen Pharmaceuticals: Research Funding; Amgen Inc.: Research Funding; Stemline: Honoraria; Novartis: Research Funding. Blum: Xencor: Research Funding; Abbvie: Honoraria; Nkarta: Research Funding; Celyad Oncology: Research Funding; AmerisourceBergen: Honoraria; Forma Therapeutics: Research Funding; Leukemia and Lymphoma Society: Research Funding; Syndax: Honoraria. Arellano: Syndax Pharmaceuticals, Inc: Consultancy; KITE Pharma, Inc: Consultancy. Schiller: Actinium Pharmaceuticals, Inc: Research Funding; Mateon: Research Funding; Tolero: Research Funding; Geron: Research Funding; Regimmune: Research Funding; Kite/Gilead: Honoraria, Research Funding, Speakers Bureau; Celator: Research Funding; Sangamo: Research Funding; Stemline Therapeutics, Inc.: Honoraria, Research Funding, Speakers Bureau; Takeda: Research Funding; PrECOG: Research Funding; Pfizer: Current equity holder in publicly-traded company, Research Funding; Karyopharm: Research Funding; Incyte: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding, Speakers Bureau; Gamida Cell Ltd.: Research Funding; FujiFilm: Research Funding; Samus: Research Funding; Trovagene: Research Funding; Daiichi-Sankyo: Research Funding; Constellation Pharmaceuticals: Research Funding; BMS/Celgene: Consultancy, Current equity holder in publicly-traded company, Research Funding, Speakers Bureau; Abbvie: Research Funding; Actuate: Research Funding; Arog: Research Funding; Delta-Fly: Research Funding; Amgen: Consultancy, Current equity holder in publicly-traded company, Honoraria, Research Funding, Speakers Bureau; Agios: Consultancy, Research Funding, Speakers Bureau; Novartis: Consultancy, Research Funding; Jazz: Consultancy, Honoraria, Research Funding, Speakers Bureau; Elevate: Research Funding; Ono-UK: Consultancy, Research Funding; Onconova: Research Funding; Deciphera: Research Funding; Astellas: Honoraria, Research Funding, Speakers Bureau; Forma: Research Funding; Genentech-Roche: Research Funding; Bio: Research Funding; Sanofi: Honoraria, Research Funding, Speakers Bureau; Pharma: Consultancy; Johnson & Johnson: Current equity holder in publicly-traded company; Biomed Valley Discoveries: Research Funding; Eli Lilly: Research Funding; ASH foundation: Other: Chair-unpaid; Sellas: Research Funding; Ono: Consultancy; Incyte: Consultancy; Ariad: Research Funding; AstraZeneca: Consultancy; Kaiser Permanente: Consultancy; Cyclacel: Research Funding; MedImmune: Research Funding; Ambit: Research Funding; Leukemia & Lymphoma Society: Research Funding; Bluebird Bio: Research Funding; Boehringer-Ingleheim: Research Funding; Cellerant: Research Funding; CTI Biopharma: Research Funding; Janssen: Research Funding; Kura Oncology: Research Funding; Pharmacyclics: Honoraria, Speakers Bureau; Millennium: Research Funding; National Marrow Donor Program: Research Funding; NIH: Research Funding; Onyx: Research Funding; Pharmamar: Research Funding; UC Davis: Research Funding; UCSD: Research Funding; Evidera: Consultancy; NCI: Consultancy; Novartis: Speakers Bureau. Olin: Astellas: Honoraria, Research Funding; Daiichi Sankyo: Research Funding; Genentech: Research Funding; Pfizer: Research Funding; Cellectis: Research Funding; Amgen: Honoraria; Abbvie: Honoraria; Actinium: Honoraria. Foran: taiho: Honoraria; syros: Honoraria; kura: Research Funding; boehringer ingelheim: Research Funding; sanofi aventis: Honoraria; trillium: Research Funding; aptose: Research Funding; abbvie: Research Funding; pfizer: Honoraria; gamida: Honoraria; actinium: Research Funding; takeda: Research Funding; certara: Honoraria; OncLive: Honoraria; bms: Honoraria; revolution medicine: Honoraria; servier: Honoraria; novartis: Honoraria; h3bioscience: Research Funding; aprea: Research Funding; sellas: Research Funding; stemline: Research Funding. Litzow: AbbVie: Research Funding; Jazz: Other: Advisory Board; Pluristem: Research Funding; Amgen: Research Funding; Omeros: Other: Advisory Board; Actinium: Research Funding; Astellas: Research Funding; Biosight: Other: Data monitoring committee. Lin: AbbVie, Aptevo Therapeutics, Astellas Pharma, Bio-Path Holdings, Celgene, Celyad, Genentech-Roche, Gilead Sciences, Incyte, Jazz Pharmaceuticals, Novartis, Ono Pharmaceutical, Pfizer, Prescient Therapeutics, Seattle Genetics, Tolero, Trovagene: Research Funding. Patel: BMS-Celgene, Agios: Membership on an entity's Board of Directors or advisory committees; Peerview: Honoraria; Aptevo Therapeutics: Research Funding. Foster: Bellicum Pharmaceuticals: Research Funding; Macrogenics: Research Funding; Rafael Pharmaceuticals: Research Funding; Macrogenics: Consultancy; Daiichi Sankyo: Consultancy; Agios: Consultancy. Cogle: Aptevo therapeutics: Research Funding; Celgene: Membership on an entity's Board of Directors or advisory committees. Vergilio: Foundation Medicine: Current Employment. Gana: The Leukemia & Lymphoma Society: Consultancy; Bausch: Current holder of individual stocks in a privately-held company. Druker: VB Therapeutics: Membership on an entity's Board of Directors or advisory committees; The RUNX1 Research Program: Membership on an entity's Board of Directors or advisory committees; GRAIL: Current equity holder in publicly-traded company; Third Coast Therapeutics: Membership on an entity's Board of Directors or advisory committees; EnLiven: Consultancy, Research Funding; Iterion Therapeutics: Membership on an entity's Board of Directors or advisory committees; Recludix Pharma, Inc.: Consultancy; Pfizer: Research Funding; Merck & Co: Patents & Royalties; Cepheid: Consultancy, Membership on an entity's Board of Directors or advisory committees; Novartis Pharmaceuticals: Membership on an entity's Board of Directors or advisory committees, Patents & Royalties; Nemucore Medical Innovations, Inc.: Consultancy; Bristol-Myers Squibb: Research Funding; Blueprint Medicines: Consultancy, Current equity holder in publicly-traded company, Membership on an entity's Board of Directors or advisory committees; Aptose Therapeutics: Consultancy, Current equity holder in publicly-traded company, Membership on an entity's Board of Directors or advisory committees; Amgen: Current equity holder in publicly-traded company, Membership on an entity's Board of Directors or advisory committees; ALLCRON: Consultancy, Membership on an entity's Board of Directors or advisory committees; Aileron: Membership on an entity's Board of Directors or advisory committees; Vincerx Pharma: Current equity holder in publicly-traded company, Membership on an entity's Board of Directors or advisory committees; Vivid Biosciences: Membership on an entity's Board of Directors or advisory committees. Byrd: Novartis, Trillium, Astellas, AstraZeneca, Pharmacyclics, Syndax: Consultancy, Honoraria; Vincerx Pharmaceuticals: Current equity holder in publicly-traded company, Membership on an entity's Board of Directors or advisory committees; Newave: Membership on an entity's Board of Directors or advisory committees. Levine: Auron: Membership on an entity's Board of Directors or advisory committees; Incyte: Consultancy; Ajax: Membership on an entity's Board of Directors or advisory committees; C4 Therapeutics: Membership on an entity's Board of Directors or advisory committees; Isoplexis: Membership on an entity's Board of Directors or advisory committees; Astellas: Consultancy; Celgene: Research Funding; Roche: Honoraria, Research Funding; Zentalis: Membership on an entity's Board of Directors or advisory committees; Prelude: Membership on an entity's Board of Directors or advisory committees; Mission Bio: Membership on an entity's Board of Directors or advisory committees; Amgen: Honoraria; Janssen: Consultancy; Gilead: Honoraria; Morphosys: Consultancy; Imago: Membership on an entity's Board of Directors or advisory committees; QIAGEN: Membership on an entity's Board of Directors or advisory committees; Lilly: Honoraria. Borate: Pfizer: Membership on an entity's Board of Directors or advisory committees, Research Funding; Blueprint Medicine: Membership on an entity's Board of Directors or advisory committees; Novartis: Membership on an entity's Board of Directors or advisory committees, Research Funding; Genentech: Membership on an entity's Board of Directors or advisory committees, Other: Advisory Board; AbbVie: Membership on an entity's Board of Directors or advisory committees, Research Funding; Jazz Pharma: Research Funding; Daiichi-Sankyo: Membership on an entity's Board of Directors or advisory committees; Takeda: Membership on an entity's Board of Directors or advisory committees; Astellas: Membership on an entity's Board of Directors or advisory committees; incyte: Membership on an entity's Board of Directors or advisory committees, Research Funding; Rampal: Membership on an entity's Board of Directors or advisory committees; Galecto, Inc.: Consultancy; Promedior: Consultancy.

Introduction: CPX-351 (United States: Vyxeos ®; Europe: Vyxeos ® Liposomal), a dual-drug liposomal encapsulation of daunorubicin and cytarabine in a synergistic 1:5 molar ratio, is approved for the treatment of newly diagnosed therapy-related acute myeloid leukemia (AML) or AML with myelodysplasia-related changes in adults and pediatric patients aged ≥1 year in the United States and in adults in the European Union. In a phase 3 study in adults aged 60 to 75 years with newly diagnosed high-risk/secondary AML, after 5 years of follow-up CPX-351 significantly improved median overall survival and remission rates versus conventional 7+3 cytarabine/daunorubicin, with a comparable safety profile. Preclinical data suggest CPX-351 may have synergistic activity with targeted agents, including the BCL-2 inhibitor venetoclax (VEN). Interim results from the V-FAST (Vyxeos - First Phase Assessment with Targeted Agents) study have demonstrated the safety and preliminary efficacy of CPX-351 in combination with VEN or midostaurin. Herein, we report the preliminary results of a subgroup analysis of adults with newly diagnosed AML treated with CPX-351 + VEN, based on age, to provide insights into the tolerability of this novel combination in younger versus older adults with AML. Methods: V-FAST is an ongoing, open-label, multicenter, multi-arm, nonrandomized, phase 1b master trial (NCT04075747) to evaluate the safety and preliminary efficacy of CPX-351 combined with targeted agents (venetoclax, midostaurin, enasidenib). Each combination arm had a dose-exploration phase (3+3 design; n ≤12) and a subsequent expansion phase (n = 20) to determine the recommended phase 2 dose (RP2D), safety, and initial efficacy of that treatment combination. Eligible patients included adults aged 18 to ≤75 years with newly diagnosed AML who were deemed fit for intensive chemotherapy and had an ECOG performance status of 0 to 2. Patients assigned to treatment with CPX-351 + VEN were to have wild type FLT3 and IDH2 based on molecular testing. The RP2D of this treatment arm was determined to be dose level 1, in which patients received CPX-351 100 units/m 2 (daunorubicin 44 mg/m 2 + cytarabine 100 mg/m 2) on Days 1, 3, and 5 + VEN 400 mg on Days 1 to 14 of the first induction. At this dose level, 1 of 6 patients in the dose-exploration phase experienced 2 dose-limiting toxicities (grade 4 neutropenia [Day 16] and grade 4 thrombocytopenia [Day 18]) that extended beyond 49 days; no dose adjustments were required and the study enrolled an additional 21 patients at this dose level. For this subgroup analysis, patients were grouped by age: 18 to ≤59 years (younger) and 60 to ≤75 years (older). Results: A total of 21 patients received CPX-351 + VEN and had sufficient data to be included in the analysis, comprising 14 patients aged 18 to ≤59 years and 7 patients aged 60 to ≤75 years. Patient baseline characteristics are shown in Table 1. The most common TEAEs of any grade in younger adults were neutropenia, febrile neutropenia, and constipation; the most common TEAEs in older adults were febrile neutropenia, thrombocytopenia, and nausea (Table 2). The most common grade ≥3 TEAEs in both age groups included febrile neutropenia, thrombocytopenia, neutropenia, and leukopenia (Table 2). TEAEs categorized as serious events included febrile neutropenia (n = 3 [younger]; n = 1 [older]), sepsis (n = 2 [younger]), ischemic stroke (n = 1 [older]), skin infection (n = 1 [older]), and AML (n = 1 [younger]). Six evaluable patients in the younger age group and 1 in the older age group died during the study due to primary causes of relapse/progression (n = 4), adverse event (n = 2), and other (n = 1; sepsis and multiorgan failure after early termination from treatment). Median platelet and neutrophil recovery times were similar between age groups (Table 3) and consistent with the previously reported safety profile of CPX-351 monotherapy. Complete remission (CR) or CR with incomplete platelet or neutrophil recovery was achieved by 6/14 (43%) evaluable younger adults and 4/6 (67%) evaluable older adults, including 5/14 (36%) and 3/6 (50%) who achieved CR. Conclusions: This analysis of preliminary results by age group from the V-FAST study supports the conclusion that the combination of CPX-351 + VEN is equally feasible with a manageable safety profile in both younger and older adult patients with newly diagnosed AML. Promising remission rates were also reported for both age groups. Figure 1 Figure 1. Disclosures Pullarkat: Amgen, Dova, and Novartis: Consultancy, Honoraria; AbbVie, Amgen, Genentech, Jazz Pharmaceuticals, Novartis, Pfizer, and Servier: Membership on an entity's Board of Directors or advisory committees. Levis: Astellas and FujiFilm: Research Funding; Jazz: Consultancy, Honoraria; Pfizer: Consultancy, Honoraria; Amgen, Astellas Pharma, Daiichi-Sankyo, FujiFilm, and Menarini: Honoraria; AbbVie: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees; Takeda: Honoraria; BMS: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees. Mannis: AbbVie, Agios, Astellas Pharma, Bristol Myers Squibb, Genentech, MacroGenics, Pfizer, and Stemline: Consultancy; Astex, Forty Seven Inc/Gilead, Glycomimetics, and Jazz Pharmaceuticals: Research Funding. Strickland: Sunesis: Research Funding; AbbVie, ArcherDx, Genentech, Incyte, Kura Oncology, Novartis, Pfizer, and Syros: Consultancy. Lin: AbbVie, Aptevo Therapeutics, Astellas Pharma, Bio-Path Holdings, Celgene, Celyad, Genentech-Roche, Gilead Sciences, Incyte, Jazz Pharmaceuticals, Novartis, Ono Pharmaceutical, Pfizer, Prescient Therapeutics, Seattle Genetics, Tolero, Trovagene: Research Funding. Faderl: Jazz Pharmaceuticals: Current Employment, Current equity holder in publicly-traded company. Chakravarthy: Jazz Pharmaceuticals: Current Employment, Current equity holder in publicly-traded company. Chandrasekaran: Jazz Pharmaceuticals: Current Employment, Current equity holder in publicly-traded company. Cheung: Jazz Pharmaceuticals: Current Employment, Current equity holder in publicly-traded company. Erba: AbbVie, Daiichi Sankyo, Forma, ImmunoGen, Jazz Pharmaceuticals, MacroGenics, Novartis, and PTC: Research Funding; AbbVie, Agios, Celgene, Incyte, Jazz Pharmaceuticals, and Novartis: Speakers Bureau; AbbVie, Agios, Amgen, Astellas Pharma, Celgene, Daiichi Sankyo, Glycomimetics, ImmunoGen, Incyte, Jazz Pharmaceuticals, MacroGenics, Novartis, and Pfizer: Consultancy; Glycomimetics: Membership on an entity's Board of Directors or advisory committees; Celgene: Membership on an entity's Board of Directors or advisory committees; Covance (AbbVie): Other: Independent Review Committee . OffLabel Disclosure: combination of CPX-351 [Vyxeos] and venetoclax in adults with previously untreated AML

Background: The use of objective endpoints is critical for the generalization and clinical implications of a study. Overall survival (OS) has traditionally been used as the gold standard for demonstrating the true clinical benefit of therapy or intervention. We systematically evaluated the proportion of different primary and secondary endpoints used in phase III randomized controlled trials (RCTs) for acute myeloid leukemia (AML), and their trends over time. Methods: Following the Preferred Reporting Items for Systematic Reviews and Meta-Analysis (PRISMA) guidelines, a comprehensive literature search was conducted on three databases (PubMed, Cochrane, and Clinical trials.gov) using MeSH terms and keywords for "Leukemia, Myeloid, Acute" AND "Randomized Controlled Trials as Topic" from January 2006 to March 2021. We screened 3290 articles. After excluding duplicates, reviews, and irrelevant articles, 241 articles reporting only phase III RCTs with primary and secondary endpoints on AML or its subtypes were included for our systematic review. Primary and secondary endpoints data were extracted from the included studies, and the frequency of various endpoints as well as their yearly frequencies were calculated. Disease-free survival (DFS) was used to represent similar outcomes including event-free survival (EFS), progression-free survival (PFS), leukemia-free survival (LFS), and relapse-free survival (RFS). Results: Our study included 241 phase III RCTs on AML. OS was the primary endpoint in 114 (47%) studies, while DFS and complete remission (CR) were reported as primary endpoints in 67 (28%) and 41 (17%) studies, respectively. Safety/adverse events, relapse rate (RR), graft versus host disease (GvHD) free survival, hematological improvement (HI), minimal residual disease (MRD), and non-relapse mortality (NRM) were used as primary endpoints in 10 (4%), 8 (3%), 5 (2%), 4 (2%), 3 (1%), and 2 (1%) studies respectively. Incidence of hospitalization, fungal disease, lung infiltrates, chronic GvHD, and allogeneic stem cell transplant each were used as primary endpoints in 1 (0.4%) study. (Table 1) Secondary endpoints followed a similar pattern as detailed in Table 2. OS (n=74, 31%), DFS (n=77, 32%) and CR (n=73, 30%) were commonly reported secondary endpoints. Safety/adverse effects, RR, mortality, quality of life (QoL), HI, MRD, incidence/length of hospitalization, and acute/chronic GvHD were used as secondary endpoints in 35 (14.5%), 15 (6%), 13 (5%), 9 (4%), 9 (4%), 7 (3%), 7 (3%), 5 (2%), and 4 (2%) studies, respectively. After 2013, increase in the use of OS (31% to 52%) and CR (15% to 17%) as a primary endpoint was noted, while the use of DFS as a primary endpoint decreased from 52% to 21%. (Table 1) For secondary endpoints, a higher trend in the use of DFS (19% to 35%) and OS (31% to 45%) and a lower trend in the use of CR (35% to 29%) was observed after 2013. (Table 2) Conclusion: Overall survival and disease-free survival were the most used primary and secondary endpoints in phase III randomized controlled trials for AML. There has been an increase in the use of clinically meaningful and objective endpoint of OS over the past 15 years in AML phase III RCTs. Figure 1 Figure 1. Disclosures Yacoub: Cara: Current equity holder in publicly-traded company; Dynavex: Current equity holder in publicly-traded company; Agios: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; ACCELERON PHARMA: Membership on an entity's Board of Directors or advisory committees; CTI Biopharma: Membership on an entity's Board of Directors or advisory committees; Novartis: Consultancy, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Incyte: Consultancy, Honoraria, Speakers Bureau; Ardelyx: Current equity holder in publicly-traded company; Seattle Genetics: Honoraria, Speakers Bureau; Hylapharm: Current equity holder in publicly-traded company. Lin: AbbVie, Aptevo Therapeutics, Astellas Pharma, Bio-Path Holdings, Celgene, Celyad, Genentech-Roche, Gilead Sciences, Incyte, Jazz Pharmaceuticals, Novartis, Ono Pharmaceutical, Pfizer, Prescient Therapeutics, Seattle Genetics, Tolero, Trovagene: Research Funding. McGuirk: Pluristem Therapeutics: Research Funding; Novartis: Research Funding; Allovir: Consultancy, Honoraria, Research Funding; Novartis: Research Funding; Gamida Cell: Research Funding; EcoR1 Capital: Consultancy; Juno Therapeutics: Consultancy, Honoraria, Research Funding; Kite/ Gilead: Consultancy, Honoraria, Other: travel accommodations, expense, Kite a Gilead company, Research Funding, Speakers Bureau; Fresenius Biotech: Research Funding; Magenta Therapeutics: Consultancy, Honoraria, Research Funding; Bellicum Pharmaceuticals: Research Funding; Astelllas Pharma: Research Funding.

While CAR T cell therapy has delivered impressive clinical efficacy in B cell malignancies, similar levels of clinical activity have not been demonstrated in acute myeloid leukemia (AML). One underlying reason for this lack of translation is the relative paucity of validated CAR T targets. Major Histocompatibility Complex Class 1 related proteins MICA and MICB along with the UL16 binding proteins 1-6 (ULBP1-6) are frequently over-expressed on AML and myelodysplastic syndrome (MDS) blasts. The Natural Killer Group 2D (NKG2D) is a single receptor able to bind MICA, MICB and ULBP1-6, thus providing a potentially powerful approach that could be exploited to target this family of targets thereby providing a novel CAR T approach for AML/MDS. Expressing the NKG2D receptor fused to the human CD3z cytoplasmic domain generates a CAR that, when expressed in primary T cells, generates a CAR T product (termed CYAD-01) that showed good anti-tumor activity in preclinical models. In clinical trials, CYAD-01 showed a good tolerability profile but with a disappointing level of clinical activity when combined with cyclophosphamide / fludarabine preconditioning (DEPLETHINK trial, NCT03466320). We hypothesised that the transient expression of MICA/MICB on the CAR T itself may inhibit the activity of the NKG2D CAR through self-targeting and consequent fratricide. We developed a single shRNA able to knockdown both MICA and MICB. Co-expression of this shRNA with the NKG2D CAR generated a second generation CAR T product termed CYAD-02 which was examined in a highly similar AML/MDS patient population and preconditioning regimen as employed in the DEPLETHINK trial. CYAD-02 was evaluated in the the first-in-human CYCLE-1 trial (NCT04167696) in patients with r/r AML/MDS. The dose-escalation phase evaluated three dose-levels (DL) (1x10 8, 3x10 8 and 1x10 9 total cells per infusion), administered as a single infusion after standard preconditioning chemotherapy (cyclophosphamide 300 mg/m²/day and fludarabine 30 mg/m²/day, daily for 3 days) according to a classic 3+3 design. As of July 2021, 11 patients have been treated with CYAD-02 at the different dose-levels (3 at each DL1 and 2 and 5 at DL3). In terms of safety and tolerability, there was no evidence of a differential safety profile of CYAD-02 within the CYCLE-1 trial as compared to that observed in the CYAD-01 clinical trial. Of note, five patients enrolled in all 3 DLs experienced Grade ≥ 3 adverse events (AE) at least possibly related to CYAD-02 (cytokine release syndrome, febrile neutropenia, white blood cell count decreased, infusion related reaction). With respect to clinical activity, seven patients in total achieved stable disease (2 at DL1, 3 at DL2 and 2 at DL3) with 4 demonstrating evidence of transient blast reduction or anti-leukemic activity (decrease of at least 50% of the bone marrow blasts). In addition, two MDS patients at DL3 achieved a marrow complete response. Overall, this suggests dose dependent response to CYAD-02. Furthermore, patients receiving CYAD-02 cells seem to display a greater duration of response and stronger blast reduction as compared to patients who received CYAD-01 in DEPLETHINK. Interestingly, peak engraftment levels were higher for CYAD-02 compared to CYAD-01 at the same dose (DEPLETHINK trial). At DL3, CYAD-02 cells could be readily detected in peripheral blood of 4/5 patients through month 2. In addition, and unlike what is reported in B cell CAR T-cells trials, there was very limited evidence of elevated homeostatic cytokines (IL-7/IL-15) following CyFlu administration with IL-15 not detected in any of the patients and IL-7 showing only a minor increase in 2 patients. The knockdown of MICA/MICB appears to have a positive contribution to the initial clinical activity of CYAD-02 as compared to that achieved with the first generation CYAD-01 CAR T, together with good safety and tolerability. The lack of homeostatic cytokines after preconditioning, likely limiting the engraftment and activity of CAR T cells, may be related to the biology of myeloid malignancies. One approach to further drive the potency of NKG2D-based CAR T cells would likely be armoring the CAR T through using the T cell as a vehicle to secrete cytokines alongside the CAR. Overall, shRNA knockdown technology provides a means to modify CAR T function and here shows that single shRNA can target two independent genes to enhance the phenotype of the CAR Ts. Disclosures Deeren: Alexion: Consultancy; BMS: Consultancy; Incyte: Consultancy; Novartis: Consultancy; Sanofi: Consultancy, Research Funding; Sobi: Consultancy; Takeda: Consultancy. Lin: AbbVie, Aptevo Therapeutics, Astellas Pharma, Bio-Path Holdings, Celgene, Celyad, Genentech-Roche, Gilead Sciences, Incyte, Jazz Pharmaceuticals, Novartis, Ono Pharmaceutical, Pfizer, Prescient Therapeutics, Seattle Genetics, Tolero, Trovagene: Research Funding. Alcantar-Orozco: Celyad Oncology: Current Employment. Dheur: Celyad Oncology: Current Employment. Breman: Celyad Oncology: Current Employment. Braun: Celyad Oncology: Current Employment. Lonez: Celyad Oncology: Current Employment. Gilham: Celyad Oncology: Current Employment. Flament: Celyad Oncology: Current Employment. Lehmann: Celyad Oncology: Current Employment.

Background: In vitro studies and emerging clinical data suggest that inhibition of spleen tyrosine kinase may have an antileukemic effect in human AML. Pts with AML and TP53 mutations (TP53m) are commonly associated with older age (≥60 years) and complex karyotype (CK) and respond poorly to standard 7 + 3 induction (IND) chemotherapy with Methods: This multicenter (13 sites), open-label, Phase 2 combination Tx study utilized Simon's 2-stage Phase 2 design and enrolled AML pts with TP53m (identified molecularly) ± CK (Cohort A) or CK (≥3 metaphase abnormalities) without TP53m (Cohort B). Pts initially received 5 days of ENTO lead-in (which was later discontinued), followed by ENTO + DEC and those who achieved CR/CRh/CRi/MLFS with up to 3 cycles of IND proceeded to consolidation (CON) Tx for up to 11 cycles (Figure 1). Pts with CRi/MLFS after IND were allowed up to 6 cycles (IND + CON) to achieve CR/CRh or stayed on Tx if they got clinical benefit or went off Tx. CON was followed by maintenance (MTN) Tx for up to 2 years from start of study Tx. Pts were eligible if aged ≥60 years, ND, and had ECOG performance status 0 - 2. Pts received ENTO 400 mg orally twice daily for 5 days during ENTO lead-in, and then every 28 days during IND, CON, and MTN + DEC 20 mg/m 2 IV days 1-10 (IND) or days 1-5 (CON) every 28 days. Response was assessed using modified 2017 ELN AML criteria. The primary endpoint was composite complete remission (CCR) rate (CR + CRh) with up to 3 cycles of IND, and CRi/MLFS that achieved CR/CRh by up to 6 cycles (IND + CON). Beyond stage 1, pt accrual to Cohort A was allowed based on pts with CRi and to Cohort B was stopped early for futility. Results: Between Oct 2017 and Feb 2020, of the 63 pts enrolled (Cohort A = 48; Cohort B = 15), pts with confirmed eligibility who started study Tx were included in the analyses (Cohort A = 45; Cohort B = 13). During lead-in, 27 pts in Cohort A and 6 pts in Cohort B received ENTOm for 5 days. All pts received ENTO + DEC except 1 pt in Cohort A who withdrew consent (WOC). Median ages of the pts were 70 years (range 60 - 84) in Cohort A and 74 years (range 65 - 86) in Cohort B. Median time (range) on Tx was 2.2 mos and 4.8 mos in Cohort A and B, respectively. Most common reasons for Tx discontinuation were adverse event (AE; 27%), Tx failure (TF; 27%) and WOC (18%) in Cohort A; TF (31%), disease progression and relapse (each 15%) in Cohort B. In each cohort, 1 pt discontinued Tx due to death from leukemia and 1 pt in Cohort A in CRh due to development of an additional genetic abnormality. Four pts (9%) in Cohort A and 1 pt (8%) in Cohort B proceeded to transplant. The CCR (CR + CRh) rates with up to 6 cycles of Tx for Cohort A and B were 13.3% and 30.8%, respectively; overall CR + CRh rates were 17.8% and 38.5% (Table 1). In Cohort A, with a median follow-up of 11.5 months, 0% were 1-year disease-free and median OS (mOS) was 6.5 months. In Cohort B, with a median follow-up of 15.1 months, 25% were 1-year disease-free and mOS was 11.5 months. Deaths within 7-, 30-, and 60-days of Tx were 0, 3 and 11 in Cohort A and 0, 0 and 2 in Cohort B. Most common treatment-related Grade ≥3 AEs in Cohort A and B were febrile neutropenia (31% and 39%) and anemia (22% and 31%) (Table 2). Overall, 83 serious AEs (SAEs) were reported in 33 pts in Cohort A and 12 SAEs in 6 pts in Cohort B; most common SAEs in Cohort A were pneumonia (18%) and respiratory failure (11%), and in Cohort B sepsis, dehydration and acute kidney injury (each 15%). Most common treatment-related grade ≥3 laboratory abnormalities in Cohort A and B were neutrophils decreased (27% and 31%), WBC count decreased (20% and 23%), and lymphocyte count decreased (18% and 15%). Conclusions: ENTO + DEC demonstrated activity in ND AML pts aged ≥60 years with TP53m ± CK and CK without TP53 but induced low CR/CRh rates and short OS consistent with previously published poor CR rates and OS in these pts. Our results differ from the high remission rate and longer OS previously reported for DEC monotherapy in AML pts with TP53m. ENTO + DEC was safe and acceptably tolerated. Novel Tx strategies that can benefit AML pts with these most adverse risk factors are urgently needed. Figure 1 Figure 1. Disclosures Ruppert: Telios Pharma: Consultancy. Mims: Leukemia and Lymphoma Society's Beat AML clinical study: Consultancy, Research Funding; Aptevo: Research Funding; Daiichi Sankyo: Consultancy, Research Funding; Glycomemetics: Research Funding; Kartos Pharmaceuticals: Research Funding; Xencor: Research Funding; Genentech: Consultancy; Abbvie: Consultancy; BMS: Consultancy; Kura Oncology: Consultancy; Syndax Pharmaceuticals: Consultancy; BMS: Consultancy; Jazz Pharmaceuticals: Consultancy; Aptevo: Research Funding. Borate: Jazz Pharma: Research Funding; Daiichi-Sankyo: Membership on an entity's Board of Directors or advisory committees; Takeda: Membership on an entity's Board of Directors or advisory committees; Blueprint Medicine: Membership on an entity's Board of Directors or advisory committees; Genentech: Membership on an entity's Board of Directors or advisory committees, Other: Advisory Board; Pfizer: Membership on an entity's Board of Directors or advisory committees, Research Funding; Novartis: Membership on an entity's Board of Directors or advisory committees, Research Funding; AbbVie: Membership on an entity's Board of Directors or advisory committees, Research Funding; Astellas: Membership on an entity's Board of Directors or advisory committees; incyte: Membership on an entity's Board of Directors or advisory committees, Research Funding; Rampal: Membership on an entity's Board of Directors or advisory committees; Galecto, Inc.: Consultancy; Promedior: Consultancy. Stein: Abbvie: Consultancy; Janssen Pharmaceuticals: Consultancy; Gilead Sciences, Inc.: Consultancy; Foghorn Therapeutics: Consultancy; Syros Pharmaceuticals, Inc.: Consultancy; Daiichi Sankyo: Consultancy; Blueprint Medicines: Consultancy; PinotBio: Consultancy; Genentech: Consultancy; Jazz Pharmaceuticals: Consultancy; Bristol Myers Squibb: Consultancy; Celgene: Consultancy; Agios Pharmaceuticals, Inc: Consultancy; Novartis: Consultancy; Astellas: Consultancy; Syndax Pharmaceuticals: Consultancy. Stock: Pfizer: Consultancy, Honoraria, Research Funding; amgen: Honoraria; agios: Honoraria; jazz: Honoraria; kura: Honoraria; kite: Honoraria; morphosys: Honoraria; servier: Honoraria; syndax: Consultancy, Honoraria; Pluristeem: Consultancy, Honoraria. Kovacsovics: AbbVie: Research Funding; Janssen Pharmaceuticals: Research Funding; Amgen Inc.: Research Funding; Novartis: Research Funding; Stemline: Honoraria; Jazz Pharmaceutials: Honoraria. Blum: Amerisource Bergen; Abbvie, Syndax: Honoraria; Forma Therapeutics, Xencor; Celyad: Research Funding. Arellano: KITE Pharma, Inc: Consultancy; Syndax Pharmaceuticals, Inc: Consultancy. Schiller: Actinium Pharmaceuticals, Inc: Research Funding; Gamida Cell Ltd.: Research Funding; Pfizer: Current equity holder in publicly-traded company, Research Funding; Forma: Research Funding; Agios: Consultancy, Research Funding, Speakers Bureau; Constellation Pharmaceuticals: Research Funding; MedImmune: Research Funding; Ambit: Research Funding; Karyopharm: Research Funding; Daiichi-Sankyo: Research Funding; Incyte: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding, Speakers Bureau; Kaiser Permanente: Consultancy; Abbvie: Research Funding; AstraZeneca: Consultancy; Genentech-Roche: Research Funding; Delta-Fly: Research Funding; Cyclacel: Research Funding; Mateon: Research Funding; Actuate: Research Funding; Onconova: Research Funding; Geron: Research Funding; Sangamo: Research Funding; Arog: Research Funding; Ariad: Research Funding; Stemline Therapeutics, Inc.: Honoraria, Research Funding, Speakers Bureau; Takeda: Research Funding; Trovagene: Research Funding; Ono-UK: Consultancy, Research Funding; Tolero: Research Funding; BMS/Celgene: Consultancy, Current equity holder in publicly-traded company, Research Funding, Speakers Bureau; Celator: Research Funding; Kite/Gilead: Honoraria, Research Funding, Speakers Bureau; Astellas: Honoraria, Research Funding, Speakers Bureau; Incyte: Consultancy; Novartis: Consultancy, Research Funding; Deciphera: Research Funding; FujiFilm: Research Funding; Samus: Research Funding; Regimmune: Research Funding; PrECOG: Research Funding; Amgen: Consultancy, Current equity holder in publicly-traded company, Honoraria, Research Funding, Speakers Bureau; Bio: Research Funding; Elevate: Research Funding; Jazz: Consultancy, Honoraria, Research Funding, Speakers Bureau; Biomed Valley Discoveries: Research Funding; Ono: Consultancy; Eli Lilly: Research Funding; Sellas: Research Funding; ASH foundation: Other: Chair-unpaid; Leukemia & Lymphoma Society: Research Funding; Bluebird Bio: Research Funding; Sanofi: Honoraria, Research Funding, Speakers Bureau; Pharma: Consultancy; Johnson & Johnson: Current equity holder in publicly-traded company; Boehringer-Ingleheim: Research Funding; Cellerant: Research Funding; CTI Biopharma: Research Funding; Janssen: Research Funding; Kura Oncology: Research Funding; Pharmacyclics: Honoraria, Speakers Bureau; Millennium: Research Funding; National Marrow Donor Program: Research Funding; NIH: Research Funding; Onyx: Research Funding; Pharmamar: Research Funding; UC Davis: Research Funding; UCSD: Research Funding; Evidera: Consultancy; NCI: Consultancy; Novartis: Speakers Bureau. Olin: Astellas: Honoraria, Research Funding; Actinium: Honoraria; Amgen: Honoraria; Abbvie: Honoraria; Cellectis: Research Funding; Daiichi Sankyo: Research Funding; Genentech: Research Funding; Pfizer: Research Funding. Foran: certara: Honoraria; pfizer: Honoraria; syros: Honoraria; taiho: Honoraria; boehringer ingelheim: Research Funding; servier: Honoraria; revolution medicine: Honoraria; trillium: Research Funding; takeda: Research Funding; abbvie: Research Funding; novartis: Honoraria; bms: Honoraria; OncLive: Honoraria; gamida: Honoraria; sanofi aventis: Honoraria; aptose: Research Funding; actinium: Research Funding; kura: Research Funding; h3bioscience: Research Funding; aprea: Research Funding; sellas: Research Funding; stemline: Research Funding. Litzow: AbbVie: Research Funding; Omeros: Other: Advisory Board; Astellas: Research Funding; Pluristem: Research Funding; Jazz: Other: Advisory Board; Actinium: Research Funding; Amgen: Research Funding; Biosight: Other: Data monitoring committee. Lin: AbbVie, Aptevo Therapeutics, Astellas Pharma, Bio-Path Holdings, Celgene, Celyad, Genentech-Roche, Gilead Sciences, Incyte, Jazz Pharmaceuticals, Novartis, Ono Pharmaceutical, Pfizer, Prescient Therapeutics, Seattle Genetics, Tolero, Trovagene: Research Funding. Cogle: Aptevo therapeutics: Research Funding; Celgene: Membership on an entity's Board of Directors or advisory committees. Vergilio: Foundation Medicine: Current Employment; Roche: Current equity holder in publicly-traded company. Gana: Bausch: Current holder of individual stocks in a privately-held company; The Leukemia & Lymphoma Society: Consultancy. Druker: The RUNX1 Research Program: Membership on an entity's Board of Directors or advisory committees; Aileron: Membership on an entity's Board of Directors or advisory committees; Novartis Pharmaceuticals: Membership on an entity's Board of Directors or advisory committees, Patents & Royalties; Recludix Pharma, Inc.: Consultancy; Third Coast Therapeutics: Membership on an entity's Board of Directors or advisory committees; Vincerx Pharma: Current equity holder in publicly-traded company, Membership on an entity's Board of Directors or advisory committees; VB Therapeutics: Membership on an entity's Board of Directors or advisory committees; GRAIL: Current equity holder in publicly-traded company; Iterion Therapeutics: Membership on an entity's Board of Directors or advisory committees; ALLCRON: Consultancy, Membership on an entity's Board of Directors or advisory committees; Amgen: Current equity holder in publicly-traded company, Membership on an entity's Board of Directors or advisory committees; Aptose Therapeutics: Consultancy, Current equity holder in publicly-traded company, Membership on an entity's Board of Directors or advisory committees; Blueprint Medicines: Consultancy, Current equity holder in publicly-traded company, Membership on an entity's Board of Directors or advisory committees; Bristol-Myers Squibb: Research Funding; EnLiven: Consultancy, Research Funding; Merck & Co: Patents & Royalties; Pfizer: Research Funding; Nemucore Medical Innovations, Inc.: Consultancy; Cepheid: Consultancy, Membership on an entity's Board of Directors or advisory committees; Vivid Biosciences: Membership on an entity's Board of Directors or advisory committees. Byrd: Vincerx Pharmaceuticals: Current equity holder in publicly-traded company, Membership on an entity's Board of Directors or advisory committees; Novartis, Trillium, Astellas, AstraZeneca, Pharmacyclics, Syndax: Consultancy, Honoraria; Newave: Membership on an entity's Board of Directors or advisory committees. Levine: Isoplexis: Membership on an entity's Board of Directors or advisory committees; Gilead: Honoraria; Zentalis: Membership on an entity's Board of Directors or advisory committees; Imago: Membership on an entity's Board of Directors or advisory committees; Ajax: Membership on an entity's Board of Directors or advisory committees; Lilly: Honoraria; Prelude: Membership on an entity's Board of Directors or advisory committees; Amgen: Honoraria; Janssen: Consultancy; Celgene: Research Funding; Roche: Honoraria, Research Funding; Auron: Membership on an entity's Board of Directors or advisory committees; C4 Therapeutics: Membership on an entity's Board of Directors or advisory committees; Incyte: Consultancy; Astellas: Consultancy; Morphosys: Consultancy; QIAGEN: Membership on an entity's Board of Directors or advisory committees; Mission Bio: Membership on an entity's Board of Directors or advisory committees. OffLabel Disclosure: Off-label use of entospletinib and decitabine.

Introduction Philadelphia positive (Ph+) acute lymphoblastic leukemia (ALL) presents with an aggressive clinical course and carries a high risk for relapse. The addition of tyrosine kinase inhibitors (TKI) has revolutionized the induction and maintenance treatment for this disease and has increased the patients achieving and maintaining complete remission. Allogeneic hematopoietic stem cell transplantation (HSCT) is the standard of care at this time for patients who achieve first complete remission (CR1); however, its impact on outcomes is debated. This systematic review and meta-analysis aimed to compare the outcomes of TKI maintenance therapy with or without HSCT in Ph+ ALL patients in CR1. Methods Following the Preferred Reporting Items for Systematic Reviews and Meta-Analysis (PRISMA) guidelines, a comprehensive literature search was conducted on PubMed, Cochrane, and Clinical trials.gov using MeSH terms and keywords for " Philadelphia chromosome ", "hematopoietic stem cell transplantation" and " protein kinase inhibitors " from date of inception to May 01, 2021. A total of 1691 records were discovered using database searching. All search results were imported into the Endnote X9.0 reference manager, and duplicates were removed. The primary and secondary screening was performed, and after excluding irrelevant and review articles, a total of 6 (3 retrospectives, 3 phase II randomized controlled trials) original articles were included reporting separate outcomes of TKI maintenance therapy (TKI cohort) and HSCT followed by TKI maintenance therapy (HSCT-TKI cohort) for Ph+ ALL in CR1. Quality evaluation was done using the NIH quality assessment tool. The inter-study variance was calculated using the Der Simonian-Laird Estimator. Proportions along with a 95% Confidence Interval (CI) were extracted to compute pooled analysis using the 'meta' package by Schwarzer et al. in the RevMan (version 5.4-1). RESULTS: A total of 413 patients from 6 studies were included for this systematic review and meta-analysis. Out of these, 222 (53.8%) had TKI maintenance after consolidation therapy and 191 (46.2%) patients had HSCT followed by TKI maintenance in CR1. The median age of the whole cohort was 49.3 (17-84) years, while the median age for HSCT-TKI patients was 47 (14-84) years. The proportion of males was 26.2% (n=90) in TKI group versus 37.5% (n=137) in the HSCT-TKI group, as reported by 5 studies. The median follow-up was 28 (0.6-149) months. Imatinib mesylate (first-generation TKI) was used in 55.6% (n=125) patients and Dasatinib (second-generation TKI) was given to 44.4% (n=100) patients. (Table 1) Overall survival (OS) was reported from 100% and 93.3% at 1 year to 49% and 33% at 5 years for TKI and HSCT-TKI cohorts, respectively. At median follow-up time of 4 (3-5) years, a trend towards poor OS was seen with TKI group as compared to HSCT-TKI group (OR 0.46, 95% CI 0.17-1.23, I 2=70%); however, the association was not statistically significant. Disease-free survival (DFS) was reported from 49.3% and 71.3% at 4 years to 38.1% and 50.5% at 5 years for TKI and HSCT-TKI cohorts, respectively. At a median follow-up time of 4 (3-5) years, the pooled analysis showed poor DFS for TKI as compared to HSCT-TKI cohort (OR 0.30, 95% CI 0.17-0.53, I 2=0%). Four studies (n=292) reported separate outcomes for relapse, it was 59.1% (87/147) for TKI versus 14.5% (n=21/145) for HSCT-TKI patients, and odds of developing relapse were higher among patients receiving TKI as compared to HSCT-TKI (OR=8.08, 95% CI=3.81-17.14, I 2=0%). Conclusion: Hematopoietic stem cell transplant in Philadelphia positive acute lymphoblastic leukemia in first complete remission followed by tyrosine kinase inhibitor maintenance therapy confers disease-free and overall survival benefit compared to tyrosine kinase inhibitors maintenance alone. Our findings confirm HSCT as a standard of care in Ph+ ALL in CR1 followed by TKI maintenance and the need for a prospective randomized clinical trial to validate these findings. Figure 1 Figure 1. Disclosures Lin: AbbVie, Aptevo Therapeutics, Astellas Pharma, Bio-Path Holdings, Celgene, Celyad, Genentech-Roche, Gilead Sciences, Incyte, Jazz Pharmaceuticals, Novartis, Ono Pharmaceutical, Pfizer, Prescient Therapeutics, Seattle Genetics, Tolero, Trovagene: Research Funding. Abhyankar: Incyte/Therakos: Consultancy, Research Funding, Speakers Bureau. McGuirk: Astelllas Pharma: Research Funding; Fresenius Biotech: Research Funding; EcoR1 Capital: Consultancy; Novartis: Research Funding; Kite/ Gilead: Consultancy, Honoraria, Other: travel accommodations, expense, Kite a Gilead company, Research Funding, Speakers Bureau; Magenta Therapeutics: Consultancy, Honoraria, Research Funding; Allovir: Consultancy, Honoraria, Research Funding; Juno Therapeutics: Consultancy, Honoraria, Research Funding; Pluristem Therapeutics: Research Funding; Bellicum Pharmaceuticals: Research Funding; Novartis: Research Funding; Gamida Cell: Research Funding.

Although outpatient autologous stem cell transplantation (ASCT) is safe and feasible in most instances, some patients undergoing planned outpatient transplantation for multiple myeloma (MM) will need inpatient admission for transplantation-related complications. We aim to evaluate the difference, if any, between outpatient and inpatient ASCT cohorts of MM patients in terms of admission rate, transplantation outcome, and overall survival. We also plan to assess whether the Hematopoietic Cell Transplantation Comorbidity Index (HCT-CI) and Karnofsky Performance Status (KPS) can predict unplanned admissions after adjusting for confounding factors. Patients with MM (n = 448) who underwent transplantation at our institution between 2009 and 2014 were included in this retrospective analysis. Patients were grouped into 3 cohorts: cohort A, planned inpatient ASCT (n = 216); cohort B, unplanned inpatient admissions (n = 57); and cohort C, planned outpatient SCT (n = 175). The statistical approach included descriptive, bivariate, and survival analyses. There were no differences among the 3 cohorts in terms of type of myeloma, stage at diagnosis, time from diagnosis to transplantation, CD34 cell dose, engraftment kinetics, and 100-day response rates. Serum creatinine was higher and patients were relatively older in both the planned inpatient (median age, 62 years; range, 33 to 80 years) and unplanned (median age, 59 years; range, 44 to 69 years) admission cohorts compared with the outpatient-only cohort (median age, 57 years; range, 40 to 70 years) (P .05). Performance status (cohort A: median, 90%; range, 60% to 100%; cohort B: 80%, 50% to 100%; cohort C: 80%, 60% to 100%) was lower (P .05) and HCT-CI score (cohort A: median, 1.78; range, 0 to 8; cohort B: 2.67, 0 to 9; cohort C: 2.16, 0 to 7) was higher (P .004) in both inpatient groups compared with the planned outpatient cohort. With a median follow up of 5 years, poor performance status (KPS 70%) appeared to be associated with worse survival (P .002). HCT-CI 2 also appeared to be associated with worse outcomes compared with HCT-CI 0 to 1, the the difference did not reach statistical significance (hazard ratio, 1.41l 95% confidence interval, 0.72 to 2.76). Only 1 patient out of 448 died from a transplantation-related cause. Outpatient transplantation for myeloma is safe and feasible. In our experience, one-third of the patients undergoing outpatient transplantation needed to be admitted for transplantation-related toxicities. Patients in this group had lower preexisting KPS and higher HCT-CI scores. Whether planned admission for this group would have prevented unplanned admissions and undue stress on patients and the healthcare system should be tested in a prospective manner.

Background: There is no standard of care treatment for Acute Myeloid Leukemia (AML) in relapse post-allogeneic hematopoietic stem cell transplant (post-HSCT), with overall 5-year survival about 5-10%. Venetoclax (Ven) is a novel BCL2 inhibitor approved by the FDA for treatment of newly diagnosed AML in combination with hypomethylating agents (HMA) or low dose cytarabine for patients unfit for intensive induction. However, data in relapsed/refractory AML are limited, especially in the post-HSCT setting. In this retrospective study, we reviewed outcomes of patients with AML relapse post-HSCT who received Ven in combination with HMA in a single center. Methods: Charts of 17 patients who had AML relapse post-HSCT treated with combination of Ven and HMA between November 2018 - March 2020 at the University of Kansas Medical Center were reviewed. We utilized descriptive statistics for baseline characteristics and outcomes, and Kaplan-Meier log-rank test for calculating overall survival. Results Seventeen patients received Ven+HMA for AML relapse post-HSCT in our center. At the time of SCT, patients were in first complete remission (CR) (n=15); second CR (n=1) and primary failure induction (1). Median age was 62 at time of relapse (31-71) years, and 8 patients were female (47%). 9 patients (53%) had adverse risk AML (ELN 2017) 8 of them were in CR1 and 1 with primary induction failure. Common mutations included DNMT3a, ASLX-1, TET2 (3); TP53 (2); IDH1/2 (2); NPM1/FLT3 (1); NPM1/IDH2 (1); NPM1 (1 transplanted in CR2); FLT3 (1). 2/17 had received Ven+HMA prior to SCT; 4 patients received HMA alone prior to SCT. 11 patients (65%) were naïve to either Ven or HMA prior to relapse. Median time to relapse was 181 (44-851) days post-HSCT. 9 (53%) patients received Azacitidine+Ven and 8 (47%) received Decitabine+Ven. HMA+Ven was the first line of therapy post-HSCT relapse in 14 patients. 2 had donor lymphocyte infusion (DLI) after either MEC or dacogen but relapsed prior to Ven+HMA. 1 had IDH (2) inhibitor. Patients received median of 2 (1-10) cycles of HMA+Ven. Six (35%) patients achieved complete remission/complete remission with incomplete hematologic recovery (CR/CRi), and 2/6 patients had negative measurable residual disease by multiparameter flow cytometry. Median overall survival was 361 days from relapse (Figure 1). 3/14 patients received subsequent DLI with Ven+HMA. Disease progression was the most common cause of death in 8/9 of patients who died during the follow up period. Most common side effects included neutropenic fever (n=8, 47%) and acute graft versus host disease (aGVHD) (n=5, 30%). 2/5 developed new aGVHD on HMA+Ven with no prior history of aGVHD. However, aGVHD was mainly grade I-II and responsive to therapy. Discussion HMA+Venetoclax demonstrates potential activity in patients with AML relapse post-HSCT with a CR/CRi rate of 35%, comparable to other salvage therapies. There were no unexpected side effect in this high-risk population. Larger studies are needed to confirm efficacy and toxicity in this setting. Disclosures McGuirk: Pluristem Ltd: Research Funding; Kite Pharmaceuticals: Consultancy, Honoraria, Research Funding, Speakers Bureau; Gamida Cell: Research Funding; Bellicum Pharmaceutical: Research Funding; Allo Vir: Consultancy, Honoraria, Research Funding; Juno Therapeutics: Consultancy, Honoraria, Research Funding; Astellas: Research Funding; Fresenius Biotech: Research Funding; Novartis: Research Funding. Lin:Aptevo: Research Funding; Abbvie: Research Funding; Bio-Path Holdings: Research Funding; Celgene: Research Funding; Gilead Sciences: Research Funding; Incyte: Research Funding; Jazz: Research Funding; Mateon Therapeutics: Research Funding; Ono Pharmaceutical: Research Funding; Pfizer: Research Funding; Prescient Therapeutics: Research Funding; Seattle Genetics: Research Funding; Tolero Pharmaceuticals: Research Funding; Trovagene: Research Funding; Genetech-Roche: Research Funding; Celyad: Research Funding; Astellas Pharma: Research Funding.

Introduction: CPX-351 (Vyxeos®; daunorubicin and cytarabine liposome for injection), a dual-drug liposomal encapsulation of daunorubicin and cytarabine in a synergistic 1:5 molar ratio, has been approved by the US FDA and the EMA for the treatment of adults with newly diagnosed, therapy-related AML or AML with myelodysplasia-related changes. The primary analysis of the pivotal phase 3 study (NCT01696084) that formed the basis for these approvals evaluated patients aged 60 to 75 years with newly diagnosed high-risk/secondary AML and found that, with a median follow-up of 20.7 months, CPX-351 significantly improved median overall survival (OS) versus conventional 7+3, with a comparable safety profile. Final 5-year follow-up results recently reported demonstrated that the OS benefit was maintained. To evaluate both quality and quantity of life, we conducted a Q-TWiST analysis of the phase 3 study to compare survival between patients receiving CPX-351 versus 7+3. Methods: Q-TWiST is used to evaluate outcomes in oncology trials by measuring how much of the survival improvement time is spent with toxicities, how much after disease progression or relapse, and how much is valuable time (ie, Time Without Symptoms of Disease and Toxicity [TWiST]). For this analysis, the OS for each patient from the 5-year follow-up analysis was partitioned into 3 health states: TOX (time before response plus any additional time with a grade 3 or 4 toxicity), TWiST (time without relapse or grade 3 or 4 toxicity), and REL (time after relapse). Q-TWiST gain was assessed as the mean time spent in each state weighted by its respective quality of life, represented by health utility (U; scale of 0.0 [indicates death] to 1.0 [indicates "perfect" health]). Q-TWiST gain was calculated as follows: Q-TWiST = (UTWiST × TWiST) + (UTOX × TOX) + (UREL × REL). The base case scenario used the intent-to-treat population, any grade 3 or 4 toxicities, TOX and REL utility weights of 0.5, and a TWiST utility weight of 1.0. Sensitivity analyses were performed for all treated patients (CPX-351: n = 153; 7+3: n = 151) and the intent-to-treat population, any and treatment-related grade 3 or 4 toxicities, and TOX and REL utility weights of 0, 0.5, and 1.0. A variation of the base case scenario was also performed for the subset of patients who achieved complete remission (CR) or CR with incomplete neutrophil or platelet recovery (CR+CRi; CPX-351: n = 73; 7+3: n = 52). When comparing across populations or studies, reporting relative Q-TWiST gains is an effective measure for evaluating clinical benefit (ie, Q-TWiST gains compared to a control; Solem CT, et al. Expert Rev Pharm Out 2018). A relative Q-TWiST gain of 15% or greater is considered a clinically important difference (CID) in oncology studies (Revicki DA, et al. Qual Life Res 2006). The relative Q-TWiST gain was calculated using the following equation: Q-TWiST difference ÷ mean OS of control arm × 100. Results: In total, 309 patients were randomized to CPX-351 (n = 153) or 7+3 (n = 156). In the base case scenario, the means difference (95% CI) for CPX-351 versus 7+3 was 183 days (60, 306) for the TWiST state, 7 days (−63, 78) for the TOX state, and 22 days (5, 38) for the REL states. The resulting means difference (95% CI) for Q-TWiST gain was 197 days (76, 319) for CPX-351 versus 7+3, and the relative Q-TWiST gain was 53.6%. Among patients who achieved CR or CRi, the means difference (95% CI) for Q-TWiST gain was 248 days (−1, 496) for CPX-351 versus 7+3, and the relative Q-TWiST gain was 39.8%. Both relative Q-TWiST gains were considerably above the standard CID of 15% for oncology. Across the various sensitivity analyses, the relative Q-TWiST gains for CPX-351 versus 7+3 varied from 48.0% to 57.6%, remaining all well above the standard CID threshold (Table). Conclusions: Results of this post hoc analysis suggest the survival benefit with CPX-351 for patients with high-risk/secondary AML are mostly from valuable time (TWiST), thus supporting the clinical benefit for patients. The relative Q-TWiST gains were well above what is considered CID (15%) in the cancer literature and were maintained across various sensitivity analyses, supporting the robustness of the benefit. In the absence of direct measures of quality of life, these results can be used together with the antileukemia effect when considering treatment options for this patient population. Disclosures Cortes: Daiichi Sankyo: Consultancy, Research Funding; Novartis: Consultancy, Research Funding; Sun Pharma: Research Funding; Pfizer: Consultancy, Research Funding; BioPath Holdings: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding; Telios: Research Funding; Astellas: Research Funding; Amphivena Therapeutics: Research Funding; Arog: Research Funding; BiolineRx: Consultancy, Research Funding; Bristol-Myers Squibb: Research Funding; Merus: Research Funding; Immunogen: Research Funding; Jazz Pharmaceuticals: Consultancy, Research Funding; Takeda: Consultancy, Research Funding. Lin:Aptevo: Research Funding; Abbvie: Research Funding; Gilead Sciences: Research Funding; Genetech-Roche: Research Funding; Incyte: Research Funding; Celyad: Research Funding; Celgene: Research Funding; Jazz: Research Funding; Mateon Therapeutics: Research Funding; Ono Pharmaceutical: Research Funding; Bio-Path Holdings: Research Funding; Astellas Pharma: Research Funding; Prescient Therapeutics: Research Funding; Pfizer: Research Funding; Trovagene: Research Funding; Tolero Pharmaceuticals: Research Funding; Seattle Genetics: Research Funding. Uy:Daiichi Sankyo: Consultancy; Pfizer: Consultancy; Agios: Consultancy; Genentech: Consultancy; Jazz Pharmaceuticals: Consultancy; Astellas Pharma: Honoraria. Ryan:Jazz Pharmaceuticals: Current Employment, Current equity holder in publicly-traded company. Faderl:Jazz Pharmaceuticals: Current Employment, Current equity holder in publicly-traded company. Lancet:Abbvie: Consultancy; Agios Pharmaceuticals: Consultancy, Honoraria; Astellas Pharma: Consultancy; Celgene: Consultancy, Research Funding; Daiichi Sankyo: Consultancy; ElevateBio Management: Consultancy; Jazz Pharmaceuticals: Consultancy; Pfizer: Consultancy.

Background: CPX-351 is a liposomal encapsulation of daunorubicin and cytarabine in a 1:5 molar ratio. In a randomized phase 3 study (CPX-351-301) conducted in older adults (60 to 75 years old) with newly diagnosed, high-risk and/or secondary AML, CPX-351 induction therapy was superior to standard 7+3 with improved rates of complete remission (CR) and overall survival (OS). In both older adults and high-risk AML, allogeneic hematopoietic cell transplantation (HCT) is frequently the preferred post-remission strategy owing to the high rates of relapse and poor overall survival with conventional chemotherapy approaches. After a median follow-up of 20.7 months, the primary pre-planned analysis found that more patients randomized to CPX-351 underwent HCT and an exploratory landmark survival analysis from the time of HCT favored CPX-351 (HR = 0.46 [95% CI: 0.24, 0.89]; one-sided P = 0.009). However, the initial protocol did not collect data related to HCT and the basis for improved HCT outcomes with CPX-351 was previously unknown. Here we present a detailed analysis of HCT outcomes in patients enrolled in the CPX-351-301 study with 5-years of follow-up. Methods: Patients age 60 to 75 years with high-risk and/or secondary AML were randomized in a 1:1 fashion to receive CPX-351 or 7+3 as induction and consolidation chemotherapy (Lancet J et al, JCO 2018). The protocol was amended to collect additional HCT-specific information, including donor and HCT characteristics and post-HCT outcomes, including rates of relapse and GVHD. Post-HCT outcomes including relapse, GVHD, and death were analyzed as competing events. Results: Of 309 randomized patients in the CPX-351-301 study, more patients achieved CR/CRi with CPX-351 vs 7+3 (48% vs 33%) allowing more patients to proceed to HCT (35% vs 25%) and more patients to proceed to HCT in remission (CPX-351: 41/73 [56%]; 7+3: 24/52 [46%]). The median age was 66 years with CPX-351 vs 65 years with standard induction among the transplanted cohorts; 16 patients in the CPX-351 transplanted arm were over the age of 70 compared to only 6 in the 7+3 arm. Other pre-HCT patient characteristics were balanced between the CPX-351 and 7+3 groups, including ECOG performance status (8% vs 5% with ECOG PS of 2), HCT-CI (median 4 vs 3), donor type (matched unrelated donor 49% vs 49%), and conditioning regimen intensity (myeloablative [17% vs 13%] vs reduced-intensity conditioning [43% vs 46%]). The Kaplan-Meier-estimated 3-year survival rate among transplanted patients was 56% with CPX-351 vs 23% with 7+3 (Figure 1A). The differences in survival consistently favored CPX-351 across patient age, AML subtype, disease status, donor type, and conditioning intensity (Figure 1B). Differences in OS were driven by a large reduction in non-relapse mortality (HR = 0.42 [95% CI: 0.21, 0.86]; Figure 1D). The cumulative incidence of acute GVHD with death as a competing event at 6 months from HCT date was 0.49 (95% CI: 0.35, 0.62) in the CPX-351 arm and 0.38 (95% CI: 0.23, 0.53) in the 7+3 arm. Conclusions: Analysis of HCT outcomes in patients enrolled in the CPX-351-301 study demonstrated that treatment with CPX-351 in older adults with high-risk and/or secondary AML resulted in more patients bridged to HCT and more patients transplanted in CR/CRi compared to 7+3, with improved OS in transplanted patients. The pattern of HCT outcomes suggests improved disease control with CPX-351 induction allowing higher HCT rates, but more importantly improved tolerability with less non-relapse mortality; this data supports the development of CPX-351 in other high-risk AML populations in which allogeneic HCT is the preferred post-remission strategy. Figure Disclosures Uy: Genentech: Consultancy; Agios: Consultancy; Pfizer: Consultancy; Daiichi Sankyo: Consultancy; Astellas Pharma: Honoraria; Jazz Pharmaceuticals: Consultancy. Lin:Abbvie: Research Funding; Pfizer: Research Funding; Trovagene: Research Funding; Prescient Therapeutics: Research Funding; Tolero Pharmaceuticals: Research Funding; Seattle Genetics: Research Funding; Ono Pharmaceutical: Research Funding; Genetech-Roche: Research Funding; Incyte: Research Funding; Jazz: Research Funding; Mateon Therapeutics: Research Funding; Gilead Sciences: Research Funding; Celyad: Research Funding; Celgene: Research Funding; Bio-Path Holdings: Research Funding; Astellas Pharma: Research Funding; Aptevo: Research Funding. Wieduwilt:Reata Pharmaceuticals: Current equity holder in publicly-traded company; Daiichi Sankyo: Membership on an entity's Board of Directors or advisory committees; Shire: Research Funding; Merck: Research Funding; Leadiant: Research Funding; Amgen: Research Funding; Macrogeneics: Research Funding. Ryan:Jazz Pharmaceuticals: Current Employment, Current equity holder in publicly-traded company. Faderl:Jazz Pharmaceuticals: Current Employment, Current equity holder in publicly-traded company. Lancet:Abbvie: Consultancy; Agios Pharmaceuticals: Consultancy, Honoraria; Astellas Pharma: Consultancy; Celgene: Consultancy, Research Funding; Daiichi Sankyo: Consultancy; ElevateBio Management: Consultancy; Jazz Pharmaceuticals: Consultancy; Pfizer: Consultancy.

Introduction Immunotherapy offers the promise of a new paradigm for patients with relapsed/refractory (R/R) acute myeloid leukemia (AML) and myelodysplastic syndromes (MDS). CD123, the IL-3 receptor alpha-chain, represents an attractive target for antibody therapies because of its high expression on AML/MDS blasts and leukemic stem cells compared to normal hematopoietic stem and progenitor cells. APVO436, a novel bispecific anti-CD123 x anti-CD3 ADAPTIR™ molecule, depleted CD123+ cells in AML patient samples ex vivo (Godwin et al. ASH 2017), reduced leukemia engraftment in a systemic AML xenograft model (Comeau et al. AACR 2018), and transiently reduced peripheral CD123+ cells in non-human primates with minimal cytokine release and in a dose-dependent fashion (Comeau et al. AACR 2019). These data provide a basis for the clinical application of APVO436 as a treatment in AML and MDS. Here, we report preliminary data from a first-in-human dose-escalation study of APVO436 in patients with R/R AML and high-risk MDS. Study Design/Methods This ongoing Phase 1/1b study (ClinicalTrials.gov: NCT03647800) was initiated to determine the safety, immunogenicity, pharmacokinetics, pharmacodynamics, and clinical activity of APVO436 as a single agent. Major inclusion criteria were: R/R AML with no other standard treatment option available, R/R MDS with > 5% marrow blasts or any peripheral blasts and failure of a hypomethylating agent, ECOG performance status ≤ 2, life expectancy > 2 months, white blood cells ≤ 25,000 cells/mm3, creatinine ≤ 2 x upper limit of normal (ULN), INR and PTT < 1.5 x ULN and alanine aminotransferase < 3 x ULN. Patients were not restricted from treatment due to cytogenetic or mutational status. Intravenous doses of APVO436 were administered weekly for up to six 28-day cycles (24 doses) with the option to continue dosing for up to 36 total cycles (144 doses). Flat and step dosing regimens were escalated using a safety-driven modified 3 + 3 design. Pre-medication with diphenhydramine, acetaminophen, and dexamethasone was administered starting with dose 1 to mitigate infusion related reactions (IRR) and cytokine release syndrome (CRS). First doses and increasing step doses of APVO436 were infused over 20-24 hours followed by an observation period of 24 hours or more. Bone marrow biopsies were performed every other cycle with responses assessed by European Leukemia Net 2017 criteria for AML or International Working Group (IWG) 2006 criteria for MDS. Results The data cut-off for this interim analysis was July 9, 2020. Twenty-eight patients with primary R/R AML (n=19), therapy-related R/R AML (n=3), or high-risk MDS (n=6) have been enrolled and received a cumulative total of 186 doses. The number of doses received per patient ranged from 1 to 43 (mean of 6.4 doses). Most patients discontinued treatment due to progressive disease; however, blast reduction was achieved in 2 patients, with one patient with MDS maintaining a durable response for 11 cycles before progressing. APVO436 was tolerated across all dose regimens in all cohorts tested. The most common adverse events (AEs), regardless of causality, were edema (32%), diarrhea (29%), febrile neutropenia (29%), fever (25%), hypokalemia (25%), IRR (21%), CRS (18%), chills (18%), and fatigue (18%). AEs ≥ Grade 3 occurring in more than one patient were: febrile neutropenia (25%), anemia (18%), hyperglycemia (14%), decreased platelet count (11%), CRS (11%), IRR (7%), and hypertension (7%). After observing a single dose limiting toxicity (DLT) at a flat dose of 9 µg, step dosing was implemented and no DLTs have been observed thereafter. No treatment-related anti-drug antibodies (ADA) were observed. Transient serum cytokine elevations occurred after several reported IRR and CRS events, with IL-6 most consistently elevated. Conclusions Preliminary results indicate that APVO436 is tolerated in patients with R/R AML and MDS at the doses and schedules tested to date, with a manageable safety profile. Dose escalation continues and the results will be updated for this ongoing study. Disclosures Watts: BMS: Membership on an entity's Board of Directors or advisory committees; Aptevo Therapeutics: Research Funding; Takeda: Membership on an entity's Board of Directors or advisory committees, Research Funding; Rafael Pharma: Membership on an entity's Board of Directors or advisory committees; Jazz: Membership on an entity's Board of Directors or advisory committees; Genentech: Membership on an entity's Board of Directors or advisory committees. Lin:Ono Pharmaceutical: Research Funding; Pfizer: Research Funding; Abbvie: Research Funding; Bio-Path Holdings: Research Funding; Astellas Pharma: Research Funding; Aptevo: Research Funding; Celgene: Research Funding; Genetech-Roche: Research Funding; Celyad: Research Funding; Prescient Therapeutics: Research Funding; Seattle Genetics: Research Funding; Mateon Therapeutics: Research Funding; Jazz: Research Funding; Incyte: Research Funding; Gilead Sciences: Research Funding; Trovagene: Research Funding; Tolero Pharmaceuticals: Research Funding. Wang:Abbvie: Consultancy; Macrogenics: Consultancy; Astellas: Consultancy; Jazz Pharmaceuticals: Consultancy; Bristol Meyers Squibb (Celgene): Consultancy; PTC Therapeutics: Consultancy; Stemline: Speakers Bureau; Genentech: Consultancy; Pfizer: Speakers Bureau. Mims:Leukemia and Lymphoma Society: Other: Senior Medical Director for Beat AML Study; Syndax Pharmaceuticals: Membership on an entity's Board of Directors or advisory committees; Kura Oncology: Membership on an entity's Board of Directors or advisory committees; Novartis: Speakers Bureau; Agios: Consultancy; Jazz Pharmaceuticals: Other: Data Safety Monitoring Board; Abbvie: Membership on an entity's Board of Directors or advisory committees. Cull:Aptevo Therapeutics: Research Funding. Patel:Agios: Consultancy; Celgene: Consultancy, Speakers Bureau; DAVA Pharmaceuticals: Honoraria; France Foundation: Honoraria. Shami:Aptevo Therapeutics: Research Funding. Walter:Aptevo Therapeutics: Research Funding. Cogle:Aptevo Therapeutics: Research Funding; Bristol Myers Squibb: Membership on an entity's Board of Directors or advisory committees. Chenault:Aptevo Therapeutics: Current Employment, Current equity holder in publicly-traded company. Macpherson:Aptevo Therapeutics: Current Employment, Current equity holder in publicly-traded company. Chunyk:Aptevo Therapeutics: Current Employment, Current equity holder in publicly-traded company. McMahan:Aptevo Therapeutics: Current Employment, Current equity holder in publicly-traded company. Gross:Aptevo Therapeutics: Current Employment, Current equity holder in publicly-traded company. Stromatt:Aptevo Therapeutics: Current equity holder in publicly-traded company.

Background: Gilteritinib, an oral FMS-like tyrosine kinase 3 (FLT3) inhibitor, demonstrated antileukemic responses in patients with FLT3-mutated (FLT3mut+) relapsed/refractory acute myeloid leukemia (AML). We report final results from a phase 1 study of once-daily oral gilteritinib plus intravenous (IV) chemotherapy in patients with newly diagnosed AML. Methods: This 4-part, open-label, phase 1 study (NCT02236013) assessed the safety/tolerability and antileukemic effects of gilteritinib plus 7+3 induction and high-dose cytarabine consolidation chemotherapy, and as single-agent maintenance therapy in adults with newly diagnosed AML. In part 1, successive cohorts of 3-6 patients received 40-200 mg/d gilteritinib (Days 4-17) and ≤2 cycles of induction (cytarabine 100 mg/m2/d IV, Days 1-7; idarubicin 12 mg/m2/d IV, Days 1-3). In part 2, patients (n=33, of which at least 15 were FLT3mut+) received the recommended 120 mg/d gilteritinib expansion dose and ≤2 cycles of the part 1 induction schedule. In part 3, patients were stratified into 2 cohorts: one receiving treatment from part 2 (n=7) and the other receiving treatment that replaced idarubicin with daunorubicin (90 mg/m2/d IV, Days 1-3; n=7). In part 4, patients (n=12) received the same induction as the part 3/daunorubicin cohort (with a reduction in cycle 2 to daunorubicin 45 mg/m2/d). During consolidation, patients received ≤3 cycles of cytarabine (1.5 g/m2 every 12 hours; Days 1, 3, and 5) and gilteritinib (Days 1-14 for parts 1-3; Days 1-56 for part 4) at the induction dose. Gilteritinib was given once daily in 28-day cycles for up to 26 cycles as maintenance therapy (maintenance phase is still ongoing). Patients achieving composite complete remission (CRc) or partial remission could undergo hematopoietic stem cell transplant (HSCT) and resume maintenance gilteritinib treatment post-HSCT. Results: As of 23 June 2020, 80 patients were allocated to treatment (safety analysis set, n=79); median age was 59.0 y (range, 23-77) and most were male (62.0%). Median follow-up for overall survival (OS) was 35.8 mo. Dose-limiting toxicities are provided in Table 1. The maximum tolerated dose was 120 mg/d. Serious treatment-related adverse events (AEs) and AEs leading to discontinuation of gilteritinib occurred in 12.7% (n=10) and 5.1% (n=4) of patients, respectively. One (1.3%) death occurred across all treatment phases. Grade ≥3 nonhematologic AEs (≥10% of patients) were increased alanine aminotransferase (13.9%), pneumonia (13.9%), sepsis (11.4%), and bacteremia (11.4%). At the end-of-induction time point, there were 44 (55.7%) total FLT3mut+ patients across all dose groups and 38 (48.1%) patients who received gilteritinib 120 mg/d. Investigator-reported CRc was achieved by 81.8% of patients across all dose groups (n=36) and 81.6% among patients who received gilteritinib 120 mg/d (n=31; Table 2). Anthracycline choice had no clear impact on CRc rate, although the number of patients in these cohorts was low. In FLT3mut+ patients who achieved CRc in any dose group, median (95% CI) duration of CRc and disease-free survival were 14.1 (4.0-29.9) and 15.3 (9.8-not reached) mo, respectively. Median OS for FLT3mut+ patients has not been reached. The survival probability (95% CI) in all FLT3mut+ patients at weeks 8, 12, 26, 52, and 104 were 97.7% (84.6%-99.7%), 95.3% (82.5%-98.8%), 92.9% (79.6%-97.7%), 83.1% (67.7%-91.5%), and 71.8% (54.6%-83.4%), respectively. In patients with FLT3 internal tandem duplication (ITD)-positive AML achieving CRc, mutational clearance (summed FLT3 ITD signal ratio of ≤10-4 after induction or consolidation) was achieved by 70% (n/N=16/23) of patients receiving a gilteritinib dose of ≥120 mg. HSCT occurred in 30.4% of the total population (n/N=24/79). Analysis of plasma inhibitory activity and pharmacokinetics of gilteritinib will be available at presentation. Conclusions: Gilteritinib plus induction and consolidation chemotherapy is well tolerated in patients with newly diagnosed AML. Favorable antileukemic responses were observed in FLT3mut+ patients regardless of anthracycline type or gilteritinib administration schedule, with a mutational clearance rate of 70.0%. Based on these results, randomized clinical trials of induction and consolidation chemotherapy plus gilteritinib vs midostaurin in FLT3mut+ AML patients have been initiated. Disclosures Pratz: AbbVie: Other: Scientific Advisory Board, Research Funding; Astellas: Other: Scientific Advisory Board, Research Funding; Boston BioMedical: Consultancy; Celgene: Other: Scientific Advisory Board; Agios: Other: Scientific Advisory Board, Research Funding; Jazz Pharmaceutical: Consultancy; Millennium: Research Funding; Daiichi Sankyo: Research Funding. Cherry:Pfizer: Other: Advisory Board; BMS: Other: Advisory Board; Kite: Other: Advisory Board. Altman:PeerView: Consultancy; ASH: Consultancy; Syros: Consultancy; Janssen: Consultancy; Genentech: Research Funding; Amphivena: Research Funding; Amgen: Research Funding; Aprea: Research Funding; ImmunoGen: Research Funding; Celgene: Research Funding; Boehringer Ingelheim: Research Funding; PrIME Oncology: Consultancy; Immune Pharmaceuticals: Consultancy; Novartis: Consultancy; Glycomimetics: Other: Data safety and monitoring committee; Daiichi Sankyo: Other: Advisory Board - no payment but was reimbursed for travel; Kura Oncology: Other: Scientific Advisory Board - no payment accepted, Research Funding; Kartos: Research Funding; AbbVie: Other: advisory board, Research Funding; Fujifilm: Research Funding; BioSight: Other: No payment but was reimbursed for travel , Research Funding; Bristol-Myers Squibb: Consultancy; Astellas: Other: Advisory Board, Speaker (no payment), Steering Committee (no payment), Research Funding; Cancer Expert Now: Consultancy; Agios: Other: advisory board, Research Funding; Theradex: Other: Advisory Board; France Foundation: Consultancy. Cruz:Takeda: Speakers Bureau. Jurcic:Celgene: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding; BMS: Consultancy, Research Funding; Daiichi-Sankyo: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding; Novartis: Consultancy, Membership on an entity's Board of Directors or advisory committees; Arog Pharmaceuticals: Research Funding; Astellas: Research Funding; Forma Therapeutics: Research Funding; Genentech: Research Funding; Kura Oncology: Research Funding; PTC Therapeutics: Research Funding; Syros Pharmaceuticals: Research Funding; AbbVie: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding. Levis:Menarini: Honoraria; Amgen: Honoraria; FujiFilm: Honoraria, Research Funding; Daiichi-Sankyo: Honoraria; Astellas: Honoraria, Research Funding. Lin:Pfizer: Research Funding; Bio-Path Holdings: Research Funding; Abbvie: Research Funding; Seattle Genetics: Research Funding; Tolero Pharmaceuticals: Research Funding; Ono Pharmaceutical: Research Funding; Prescient Therapeutics: Research Funding; Incyte: Research Funding; Genetech-Roche: Research Funding; Gilead Sciences: Research Funding; Aptevo: Research Funding; Celyad: Research Funding; Celgene: Research Funding; Astellas Pharma: Research Funding; Mateon Therapeutics: Research Funding; Jazz: Research Funding; Trovagene: Research Funding. Perl:Bayer HealthCare Pharmaceuticals: Research Funding; Syndax: Consultancy, Honoraria; Jazz: Honoraria, Other; Arog Pharmaceuticals Inc: Other: uncompensated consulting, travel costs for meetings; Biomed Valley Discoveries: Research Funding; Agios: Consultancy, Honoraria, Other; FUJIFILM Pharmaceuticals USA, Inc: Research Funding; AbbVie Inc: Consultancy, Honoraria, Other, Research Funding; Loxo Oncology Inc, a wholly owned subsidiary of Eli Lilly & Company: Consultancy, Honoraria, Other; Takeda: Honoraria, Other: Travel costs for meeting; Astellas: Consultancy, Honoraria, Other: writing/editorial support, travel costs for meeting presentations related to study, Research Funding; Leukemia & Lymphoma Society, Beat AML: Consultancy; New Link Genetics: Honoraria, Other; Daiichi Sankyo: Consultancy, Honoraria, Other: Writing/editorial support, travel costs for meetings, Research Funding; FORMA Therapeutics: Consultancy, Honoraria, Other; Actinium Pharmaceuticals Inc: Consultancy, Honoraria, Research Funding; Novartis: Honoraria, Other, Research Funding. Podoltsev:Arog Pharmaceuticals: Research Funding; Astex Pharmaceuticals: Research Funding; Jazz Pharmaceuticals: Research Funding; Sunesis Pharmaceuticals: Research Funding; Boehringer Ingelheim: Research Funding; Daiichi Sankyo: Research Funding; Astellas Pharma: Research Funding; CTI biopharma: Consultancy, Honoraria, Research Funding; Bristol-Myers Squib: Consultancy, Honoraria; Genentech: Research Funding; Novartis: Consultancy, Honoraria; Celgene: Consultancy, Honoraria, Research Funding; Samus Therapeutics: Research Funding; Agios Pharmaceuticals: Consultancy, Honoraria; Pfizer: Consultancy, Honoraria, Research Funding; Incyte: Consultancy, Honoraria; Blueprint Medicines: Consultancy, Honoraria; Alexion: Consultancy, Honoraria; Kartos Therapeutics: Research Funding; AI Therapeutics: Research Funding. Schiller:Abbvie: Research Funding; Actinium: Research Funding; Ariad: Research Funding; Amgen: Consultancy, Current equity holder in publicly-traded company, Research Funding, Speakers Bureau; AstraZeneca: Consultancy; Incyte: Consultancy, Research Funding, Speakers Bureau; Novartis: Consultancy, Research Funding; Ono Pharma: Consultancy; Kite Pharma: Research Funding; Stemline: Speakers Bureau; Gilead: Speakers Bureau; Celgene: Research Funding, Speakers Bureau; Sanofi: Speakers Bureau; Agios: Consultancy, Research Funding, Speakers Bureau; DeltaFly: Research Funding; Deciphera: Research Funding; Daiichi Sankyo: Research Funding; Cyclacel: Research Funding; Constellation: Research Funding; Celator: Research Funding; Astellas Pharma: Honoraria, Research Funding; Bristol-Myers Squibb: Current equity holder in publicly-traded company, Research Funding; Forma: Research Funding; FujiFilm: Research Funding; Gamida: Research Funding; Genentech-Roche: Research Funding; Geron: Research Funding; Jazz Pharmaceuticals: Research Funding; Karyopharm: Research Funding; Mateon: Research Funding; MedImmune: Research Funding; Onconova: Research Funding; Pfizer: Current equity holder in publicly-traded company, Research Funding; Regimmune: Research Funding; Samus: Research Funding; Sangamo: Research Funding; Tolero: Research Funding; Trovagene: Research Funding; Kaiser Permanente: Consultancy; Johnson & Johnson: Current equity holder in publicly-traded company. Hill:Targeted Molecular Diagnostics: Patents & Royalties: US7862995; Astellas: Current Employment; Ligacept, LLC: Current equity holder in publicly-traded company, Patents & Royalties: US9051388, US9683222. James:Astellas: Current Employment. Lu:Astellas: Current Employment. Tiu:Astellas Pharma Global Development: Current Employment; Eli Lilly & Company: Current equity holder in publicly-traded company, Ended employment in the past 24 months. OffLabel Disclosure: New Indication

7026 Background: CPX-351 (US: Vyxeos; EU: Vyxeos Liposomal), a dual-drug liposomal encapsulation of daunorubicin and cytarabine in a synergistic 1:5 molar drug ratio, is approved by the US FDA and EMA for adults with newly diagnosed t-AML or AML with myelodysplasia-related changes. Preclinical data suggest CPX-351 may exert synergistic activity when combined with agents such as the BCL-2 inhibitor venetoclax (VEN) or FLT3 inhibitor midostaurin (MIDO). Methods: V-FAST (Vyxeos – First Phase Assessment With Targeted Agents) is an open-label, multicenter, phase 1b master trial (NCT04075747) to evaluate safety and establish the recommended phase 2 dose (RP2D) of CPX-351 combined with targeted agents in patients (pts) aged 18-75 y with untreated AML who are fit for intensive chemotherapy. The study includes a dose-exploration phase (3+3 design) and subsequent expansion phase. Pts received CPX-351 (dose level 1 for first induction [DL1]: 100 units/m2 on Days 1, 3, and 5) plus VEN (Arm A; DL1: 400 mg on Days 1-14), MIDO (Arm B; DL1: 50 mg BID on Days 8-21), or the IDH2 inhibitor enasidenib ([ENA] Arm C; DL1: 100 mg on Days 8-28) based on mutation testing. Results: Among 21 pts with available data enrolled by 11/06/20 (24 pts enrolled total; data cut-off: 01/19/21), the median age was 54 y (range: 35, 69). In Arm A (n = 17), 11 (65%) pts had de novo AML, 5 (29%) had an antecedent hematologic disorder (2 [12%] had myelofibrosis), and 2 (12%) had t-AML; 12 (71%) had adverse-risk AML; and 6 (35%) had mutated TP53. In Arms B (n = 3) and C (n = 1), all pts had intermediate-risk de novo AML. DL1 was the RP2D in Arms A and B; the RP2D in Arm C is still under investigation. In Arm A, 1/6 pts in the dose-exploration phase had 2 dose-limiting toxicities (DLTs) of grade 4 neutropenia and thrombocytopenia that extended beyond 49 days; no DLTs have occurred for Arms B and C. The combinations exhibited manageable safety profiles (Table). Of pts with available response data, complete remission (CR) or CR with incomplete platelet or neutrophil recovery was achieved by 6/14 (43%) pts in Arm A, including 4 (29%) with CR. All pts in Arms B and C achieved CR. Conclusions: These preliminary results suggest CPX-351 can be combined with VEN and MIDO with manageable toxicities in newly diagnosed AML pts, with DL1 determined to be the RP2D. The study is ongoing and actively enrolling pts; updated results will be presented at the meeting. Clinical trial information: NCT04075747. [Table: see text]

Umbilical cord blood (UCB) engraftment is in part limited by graft cell dose, generally one log less than that of bone marrow (BM)/peripheral blood (PB) cell grafts. Strategies toward increasing hematopoietic stem/progenitor cell (HSPC) homing to BM have been assessed to improve UCB engraftment. Despite recent progress, a complete understanding of how HSPC homing and engraftment are regulated is still elusive. We provide evidence that blocking erythropoietin (EPO)-EPO receptor (R) signaling promotes homing to BM and early engraftment of UCB CD34+ cells. A significant population of UCB CD34+ HSPC expresses cell surface EPOR. Exposure of UCB CD34+ HSPC to EPO inhibits their migration and enhances erythroid differentiation. This migratory inhibitory effect was reversed by depleting EPOR expression on HSPC. Moreover, systemic reduction in EPO levels by hyperbaric oxygen (HBO) used in a preclinical mouse model and in a pilot clinical trial promoted homing of transplanted UCB CD34+ HSPC to BM. Such a systemic reduction of EPO in the host enhanced myeloid differentiation and improved BM homing of UCB CD34+ cells, an effect that was overcome with exogenous EPO administration. Of clinical relevance, HBO therapy before human UCB transplantation was well-tolerated and resulted in transient reduction in EPO with encouraging engraftment rates and kinetics. Our studies indicate that systemic reduction of EPO levels in the host or blocking EPO-EPOR signaling may be an effective strategy to improve BM homing and engraftment after allogeneic UCB transplantation. This clinical trial was registered at www.ClinicalTrials.gov (#NCT02099266).

PURPOSE Effective treatment options are limited for patients with acute myeloid leukemia (AML) who cannot tolerate intensive chemotherapy. An international phase Ib/II study evaluated the safety and preliminary efficacy of venetoclax, a selective B-cell leukemia/lymphoma-2 inhibitor, together with low-dose cytarabine (LDAC) in older adults with AML. PATIENTS AND METHODS Adults 60 years or older with previously untreated AML ineligible for intensive chemotherapy were enrolled. Prior treatment of myelodysplastic syndrome, including hypomethylating agents (HMA), was permitted. Eighty-two patients were treated at the recommended phase II dose: venetoclax 600 mg per day orally in 28-day cycles, with LDAC (20 mg/m2 per day) administered subcutaneously on days 1 to 10. Key end points were tolerability, safety, response rates, duration of response (DOR), and overall survival (OS). RESULTS Median age was 74 years (range, 63 to 90 years), 49% had secondary AML, 29% had prior HMA treatment, and 32% had poor-risk cytogenetic features. Common grade 3 or greater adverse events were febrile neutropenia (42%), thrombocytopenia (38%), and WBC count decreased (34%). Early (30-day) mortality was 6%. Fifty-four percent achieved complete remission (CR)/CR with incomplete blood count recovery (median time to first response, 1.4 months). The median OS was 10.1 months (95% CI, 5.7 to 14.2), and median DOR was 8.1 months (95% CI, 5.3 to 14.9 months). Among patients without prior HMA exposure, CR/CR with incomplete blood count recovery was achieved in 62%, median DOR was 14.8 months (95% CI, 5.5 months to not reached), and median OS was 13.5 months (95% CI, 7.0 to 18.4 months). CONCLUSION Venetoclax plus LDAC has a manageable safety profile, producing rapid and durable remissions in older adults with AML ineligible for intensive chemotherapy. High remission rate and low early mortality combined with rapid and durable remission make venetoclax and LDAC an attractive and novel treatment for older adults not suitable for intensive chemotherapy.

Patients undergoing high-dose chemotherapy and autologous hematopoietic cell transplantation (auto-HCT) are at risk for multiple morbidities, including mucosal inflammation and neutropenic fever, both related to neutropenia. Evidence from our preclinical work in an umbilical cord blood (UCB) transplantation murine model suggests that treatment with hyperbaric oxygen (HBO) before UCB infusion improves UCB CD34+ cell engraftment by reducing erythropoietin levels. A pilot clinical trial using HBO in patients undergoing UCB transplantation showed improvement in kinetics of blood count recovery. In this study, we evaluated HBO in combination with auto-HCT. Our primary aim was to determine the safety of HBO in this setting and secondarily to determine its efficacy in reducing time to neutrophil and platelet engraftment compared with matched historic controls. Patients with multiple myeloma, non-Hodgkin lymphoma, and Hodgkin disease eligible for auto-HCT were included. On day 0, patients received HBO treatment consisting of exposure to 2.5 atmosphere absolutes for a total of 90 minutes, in a monoplace hyperbaric chamber, breathing 100% oxygen. Six hours after the start of HBO, peripherally mobilized stem/progenitor cells were infused and patients were followed daily for toxicity and blood count recovery. All patients received daily granulocyte colony-stimulating factor starting on day +5 and until absolute neutrophil count (ANC) of ≥1500 or ANC of 500 for 3 consecutive days. A matched historic cohort of 225 patients who received auto-HCT between January 2008 and December 2012 was chosen for comparison and matched on sex, age, conditioning regimen, and disease type. We screened 26 patients for this study; 20 were treated and included in the primary analysis, and 19 completed the HBO therapy and were included in the secondary analysis. Although the median time to neutrophil count recovery was 11 days in both the HBO and control cohorts, the Kaplan-Meier estimates of the full distributions indicate that the time to neutrophil recovery was generally about 1 day sooner for HBO versus historical controls (log-rank P = .005; range, 9 to 13 for HBO patients and 7 to 18 for controls). The median time to platelet count recovery was 16 days (range, 14 to 21) for HBO versus 18 days (range, 11 to 86) for controls (log-rank P © 2019 American Society for Blood and Marrow Transplantation.

Background The SARS–CoV-2 pandemic has assaulted all aspects of daily life. Medical professionals in oncology face additional challenges with balancing prompt cancer diagnosis and urgent treatment against potential COVID-19 exposure risk in these high-risk patients. We designed this prospective freewill study to offer testing for SAR2-CoV-2 viral RNA and/or anti-COVID-19, respectively in asymptomatic medical and research staff who work in direct contact with cancer patients. The overall goal was to evaluate the prevalence of infection in this group of asymptomatic healthcare providers to reduce exposure of cancer patients to asymptomatic staff. Methods Asymptomatic medical and research staff who work in direct contact with cancer patients were asked to voluntarily be tested for either SARS–CoV-2 viral RNA or antibodies or both. Either NP swabs and/or blood samples (EDTA tube) were collected. Tests are performed at Sinochips Kansas LLC, Sinochips Diagnostics (CLIA number:17D2176068, CAP number: 8709463). The PCR test is performed with FDA authorized 2019-Novel Coronavirus (2019-nCoV) Real-Time RT-PCR Diagnostic Panel EUA. The Elecsys® Anti-SARS-CoV-2 (Roche Diagnostics) immunoassay was used to qualitative detection of antibodies to SARS-CoV-2 in human plasma. Results From 06/18/2020 to 12/18/2020, 861 participated in the study. 1095 tests were completed for SAR2-CoV-2 virus infection, and 918 were completed for antibody. Amount participants, 530 had both virus and antibody tested. 235 were tested more than once for viral infection and 166 were tested more than once for the antibody. Median age of participants was 39 years (IQR 32-51 years). Among these 84.7% were females, 84.4% white, 6.7% African American, 4.8% Asian and 84.7% non-Hispanic. The cumulative incidence of a positive test for the virus was 2.2% (16/712), and for the antibody test was 3.8% (26/679). 5 had both viral and antibody tests positive, with an average time of 4.1 weeks from viral testing positivity to detectable antibody among 3 cases and 2 cases with both viral infection and antibody detected at same time. There were 3 cases virus was detected more than once after turning positive. 2 remained positive at 16 and 22 days after initial test and one turned negative at 36 days as of last follow up. There were 7 cases where the antibody was tested more than once after turning positive and all 7 remained positive as of last follow up (range 7-103 days). Conclusion Prospective voluntary testing in asymptomatic medical and research staff who work in direct contact with cancer patients was feasible and resulted in identification of asymptomatic carriers who then placed in quarantine, thereby limiting exposure to cancer patients. Medical and research staff who work with cancer patients are general very cautious and the frequency of infections were significantly lower than general society. In addition, it seems that 1) virus and antibody may co-exist in the same person after exposure, and 2) the antibody may last for a relatively long time. Citation Format: Weijing Sun, Andrew K. Godwin, Kathan Mehta, Natalie Streeter, Elizabeth Wulff-Burchfield, Anup Kasi, Tara L. Lin, Joaquina Baranda, Joseph McGuirk, Ziyan Pessetto, Adam Pessetto, B.J. Broome, Terry Tsue, Roy Jensen. Prospective voluntary SARS-CoV-2 virus and anti-COVID-19 antibody tests in asymptomatic medical and research staff who work in direct contact with cancer patients: A single center study [abstract]. In: Proceedings of the AACR Virtual Meeting: COVID-19 and Cancer; 2021 Feb 3-5. Philadelphia (PA): AACR; Clin Cancer Res 2021;27(6_Suppl):Abstract nr P13.

Background T-cells engineered to express a chimeric antigen receptor (CAR) based on the NKG2D receptor (NKG2D CAR) targeting the 8 NKG2D ligands (MICA/B, ULBP1-6) over-expressed by a large variety of malignancies have been developped to treat patients, including patients with acute myeloid leukemia (AML) and myelodysplastic syndrome (MDS). Previously, CYAD-01, the first generation of NKG2D CAR T-cell products, was evaluated in several Phase I clinical trials and showed initial signals of objective clinical responses in patients with r/r AML and MDS, albeit with short durability. Preclinical data have shown that NKG2D ligands MICA and MICB are transiently upregulated on activated CAR T-cells, and target-dependent killing of CAR T-cells post-infusion can potentially occur, leading to short in vivo persistence. In an effort to increase the persistence and potency of the NKG2D CAR T-cells, CYAD-02 was developed as a next-generation product using a non-gene editing approach to silence the expression of MICA and MICB. Aim MICA and MICB were down-regulated by inserting a single optimized short hairpin RNA (shRNA) targeting both MICA and MICB within the NKG2D CAR construct. This next-generation NKG2D CAR T-cell product is manufactured with the OptimAb process, resulting in CAR T-cells with a higher frequency of early memory T-cells secreting high levels of cytokines upon activation, and is referred to as CYAD-02. Results As compared to CYAD-01, CYAD-02 cell expansion in vitro was 3-fold increased. In an in vivo AML model, CYAD-02 showed 10-fold higher engraftment 1 week after injection and improved anti-tumor activity as compared to CYAD-01 manufactured with the initial mAb process. This led to a 2.6-fold increase of mouse survival as compared to CYAD-01 in a stress-test aggressive AML model where the dose of CYAD-01 was titrated down for minimal activity (figure). The first-in-human study evaluating CYAD-02, the CYCLE-1 study (NCT04167696), has been initiated in early 2020 in patients with r/r AML/MDS. The study evaluates three dose-levels of CYAD-02 (1x108, 3x108 and 1x109 cells/infusion), administered as a single infusion after non-myeloablative preconditioning chemotherapy (cyclophosphamide 300 mg/m²/day and fludarabine 30 mg/m²/day, daily for 3 days, CyFlu) according to a classical Fibonacci 3+3 design. As of August 2020, 6 patients have been treated with CYAD-02 at the dose of 1x108 or 3x108 cells/infusion. To date, the results demonstrate the safety and tolerability for CYAD-02 in patients with r/r AML and MDS with no dose-limiting toxicity observed. The study is currently enrolling at 1x109 cells/infusion. The CYAD-02 safety profile and preliminary clinical activity data together with the pharmacokinetics evaluation from the complete dose escalation segment will be provided at the time of presentation. Conclusion/summary The CYAD-02 is the first autologous CAR T-cell product based on the non-gene edited shRNA technology used to treat patients. This next generation NKG2D CAR T-cell product is currently investigated in the CYCLE-1 Phase I study in r/r AML/MDS patient population, a difficult to target disease due in part to the absence of truly AML-specific surface antigens, its rapid clinical progression and the absence of disease control by the CyFlu preconditioning. Both the anti-MICA and MICB shRNA hairpin and the OptimAb manufacturing process for CYAD-02 aim to improve CAR T-cell persistence and clinical responses. Figure Disclosures Lin: Mateon Therapeutics: Research Funding; Aptevo: Research Funding; Abbvie: Research Funding; Ono Pharmaceutical: Research Funding; Incyte: Research Funding; Gilead Sciences: Research Funding; Jazz: Research Funding; Astellas Pharma: Research Funding; Bio-Path Holdings: Research Funding; Celgene: Research Funding; Celyad: Research Funding; Genetech-Roche: Research Funding; Seattle Genetics: Research Funding; Tolero Pharmaceuticals: Research Funding; Trovagene: Research Funding; Prescient Therapeutics: Research Funding; Pfizer: Research Funding. Demoulin:Celyad Oncology: Current Employment. Fontaine:Celyad Oncology: Current Employment. Sotiropoulou:Celyad Oncology: Current Employment. Alcantar-Orozco:Celyad Oncology: Current Employment. Breman:Celyad Oncology: Current Employment. Dheur:Celyad Oncology: Current Employment. Braun:Celyad Oncology: Current Employment. Lonez:Celyad Oncology: Current Employment. Gilham:Celyad Oncology: Current Employment. Flament:Celyad Oncology: Current Employment. Lehmann:Celyad Oncology: Current Employment.

Objective/Background: Cytomegalovirus (CMV) causes significant morbidity and mortality in CMV seropositive patients undergoing umbilical cord blood transplants (UCBT). Our study aimed to describe the incidence of CMV reactivation and burden of disease, as well as the tolerability of an intensive prevention strategy as compared to historical prevention. Methods: This was a retrospective chart review of 33 CMV seropositive patients that underwent UCBT. The intensive prevention strategy in UCBT consisted of ganciclovir 5 mg/kg/d intravenously or valganciclovir 900 mg by mouth daily initiated at the beginning of the conditioning regimen until Day −2. Then from Day −1 to Day +100, patients received valacyclovir 2 g by mouth three times daily, and from Day +101 to Day +365, acyclovir 800 mg by mouth twice daily. Historical standard prevention was acyclovir 800 mg by mouth twice daily initiated at the beginning of the conditioning regimen until Day +365. Results: Thirty-three patients were included from 2008 to 2014. There were no differences in the adverse effects experienced between the two regimens (p = .4). CMV reactivation occurred significantly later with intensive prevention (p = .003). The median CMV viral titer at reactivation was lower in the intensive versus the historic prevention (1,800 copies/mL and 2,700 copies/mL, respectively), but was not significantly different. CMV disease occurred significantly less often in the intensive group (p = .039). Conclusion: The results from this study indicate that the intensive prevention strategy was well tolerated, significantly delayed CMV reactivation, and patients had less CMV disease. Keywords: CMV disease, CMV reactivation, CMV viremia, Cytomegalovirus, Intensive prevention, Umbilical cord blood transplant