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Gating strategy, primary AML cytotoxicity assay,additional cell liens for pH2AX assay and caspase assay, and h7G3ec antibody sequence

Treatment choices for acute myelogenous leukemia (AML) patients resistant to conventional chemotherapies are limited and novel therapeutic agents are needed. IL3 receptor alpha (IL3Rα, or CD123) is expressed on the majority of AML blasts, and there is evidence that its expression is increased on leukemic relative to normal hematopoietic stem cells, which makes it an attractive target for antibody-based therapy. Here, we report the generation and preclinical characterization of SGN-CD123A, an antibody–drug conjugate using the pyrrolobenzodiazepine dimer (PBD) linker and a humanized CD123 antibody with engineered cysteines for site-specific conjugation. Mechanistically, SGN-CD123A induces activation of DNA damage response pathways, cell-cycle changes, and apoptosis in AML cells. In vitro, SGN-CD123A–mediated potent cytotoxicity of 11/12 CD123+ AML cell lines and 20/23 primary samples from AML patients, including those with unfavorable cytogenetic profiles or FLT3 mutations. In vivo, SGN-CD123A treatment led to AML eradication in a disseminated disease model, remission in a subcutaneous xenograft model, and significant growth delay in a multidrug resistance xenograft model. Moreover, SGN-CD123A also resulted in durable complete remission of a patient-derived xenograft AML model. When combined with a FLT3 inhibitor quizartinib, SGN-CD123A enhanced the activity of quizartinib against two FLT3-mutated xenograft models. Overall, these data demonstrate that SGN-CD123A is a potent antileukemic agent, supporting an ongoing trial to evaluate its safety and efficacy in AML patients (NCT02848248). Mol Cancer Ther; 17(2); 554–64. ©2017 AACR.

Uproleselan (GMI-1271) is a novel E-selectin antagonist that disrupts cell survival pathways, enhances chemotherapy response, improves survival in mouse xenograft and syngeneic models, and decreases chemotherapy toxicity in vivo. A phase 1/2 study evaluated the safety, tolerability, and antileukemic activity of uproleselan (5-20 mg/kg) with MEC (mitoxantrone, etoposide, and cytarabine) among patients with relapsed/refractory (R/R) acute myeloid leukemia (AML). Among the first 19 patients, no dose-limiting toxicities were observed. The recommended phase 2 dose (RP2D) was 10 mg/kg twice daily. An additional 47 patients with R/R AML were treated with uproleselan at the RP2D plus MEC. At the RP2D, the remission rate (complete response [CR]/CR with incomplete count recovery [CRi]) was 41% (CR, 35%), and the median overall survival (OS) was 8.8 months. In a separate cohort, 25 newly diagnosed patients age ≥60 years received uproleselan at the RP2D plus cytarabine and idarubicin (7 + 3). In these frontline patients, the CR/CRi rate was 72% (CR, 52%), and the median OS was 12.6 months. The addition of uproleselan was associated with low rates of oral mucositis. E-selectin ligand expression on leukemic blasts was higher in patients with relapsed vs primary refractory AML and in newly diagnosed older patients with high-risk cytogenetics and secondary AML. In the R/R cohort, E-selectin expression >10% was associated with a higher response rate and improved survival. The addition of uproleselan to chemotherapy was well tolerated, with high remission rates, low induction mortality, and low rates of mucositis, providing a strong rationale for phase 3 randomized confirmatory studies. This trial was registered at www.clinicaltrials.gov as #NCT02306291.

Treatment choices for acute myelogenous leukemia (AML) patients resistant to conventional chemotherapies are limited and novel therapeutic agents are needed. IL3 receptor alpha (IL3Rα, or CD123) is expressed on the majority of AML blasts, and there is evidence that its expression is increased on leukemic relative to normal hematopoietic stem cells, which makes it an attractive target for antibody-based therapy. Here, we report the generation and preclinical characterization of SGN-CD123A, an antibody–drug conjugate using the pyrrolobenzodiazepine dimer (PBD) linker and a humanized CD123 antibody with engineered cysteines for site-specific conjugation. Mechanistically, SGN-CD123A induces activation of DNA damage response pathways, cell-cycle changes, and apoptosis in AML cells. In vitro, SGN-CD123A–mediated potent cytotoxicity of 11/12 CD123+ AML cell lines and 20/23 primary samples from AML patients, including those with unfavorable cytogenetic profiles or FLT3 mutations. In vivo, SGN-CD123A treatment led to AML eradication in a disseminated disease model, remission in a subcutaneous xenograft model, and significant growth delay in a multidrug resistance xenograft model. Moreover, SGN-CD123A also resulted in durable complete remission of a patient-derived xenograft AML model. When combined with a FLT3 inhibitor quizartinib, SGN-CD123A enhanced the activity of quizartinib against two FLT3-mutated xenograft models. Overall, these data demonstrate that SGN-CD123A is a potent antileukemic agent, supporting an ongoing trial to evaluate its safety and efficacy in AML patients (NCT02848248). Mol Cancer Ther; 17(2); 554–64. ©2017 AACR.

Decitabine (Dec) and Azacitidine (Aza) that target DNA methyltransferase 1 (DNMT1) are hypomethylating agents (HMAs) approved to treat acute myeloid leukemia (AML) in combination with Venetoclax (Ven). The combination is also used to treat high-risk myelodysplastic syndromes, especially TP53-mutated (TP53mut) cases in which responses to HMA alone are short-lived. In most patients (pts), however, myelosuppression from treatment leads to frequent Ven duration and/or dose-reductions, and/or cycle delays. An approach to decrease HMA-mediated myelosuppression but maintain S-phase dependent DNMT1-targeting, evaluated in a previous clinical trial (https://doi.org/10.1111/bjh.16281), is to administer noncytotoxic doses/concentrations of Dec (0.2 mg/kg; ~5 mg/m 2) by a frequent-distributed schedule of 1X/week. An approach to decrease Ven mediated myelosuppression but maintain cooperation with HMA, shown in pre-clinical studies, is to administer a single-dose prior to HMA. Ven can depolarize mitochondrial membranes; mitochondrial membrane-potential is essential to function of the mitochondrial enzyme DHODH that produces cytidine/deoxycytidine that competes with HMA in cells. Thus, Ven prior to HMA dosing temporarily inhibits de novo pyrimidine synthesis, to counter a major mechanism of resistance to HMA in MDS/AML, without suppressing normal myelopoiesis (https://doi.org/10.1182/blood-2020-143200). We conducted a retrospective analysis of all pts with TP53mut MDS or AML treated with weekly Ven and low-dose subcutaneous Dec at our institution. We analyzed the characteristics of these pts, response to therapy, and outcomes using standard descriptive statistics. Mutational testing was performed using a commercial next-generation sequencing (NGS) panel. Five pts, 3 male and 2 female, with TP53mut MDS or AML were treated with weekly Ven 400 mg on D1 and subcutaneous Dec 0.2 mg/kg on D2, administered weekly in 28 day cycles. Two pts had MDS (1 de novo, 1 treatment related) and 3 pts had AML (1 de novo, 2 secondary from prior MDS). Four pts (80%) received the treatment in frontline, all with poor performance status (PS), and 1 pt (20%) had R/R disease. Median age at diagnosis was 79 years [41-82]. The only young pt had prolonged severe cytopenias after 1 cycle Dec standard dosing during the peak of COVID-19 pandemic so was switched to this regimen. Of the 4 frontline treated pts, 2 pts had high-risk MDS, and 2 pts had adverse risk AML. The R/R pt had high-risk MDS transformed to AML that was refractory to 2 prior lines of therapy: standard Aza/Ven x5 cycles, then standard Vyxeos. Disease cytogenetics were complex in all pts. 60% (3/5) pts had sole TP53mut on NGS, with median variant allelic frequency (VAF) 48% [28-79]. 80% (4/5) pts were transfusion dependent prior to treatment. Median time to initiating therapy was 7 days from initial or refractory diagnosis [3-59] and median follow-up was 7.8 months (mo) [2.9-11.4]. The overall response rate (ORR) was 100%: 4/4 frontline pts had complete remissions (CR), and the 1 R/R pt achieved morphologic leukemia-free state (MLFS). Median time to best response was 2.9 mo. 50% (2/4) pts became transfusion independent. 40% (2/5) pts lost their TP53mut at best response, and another 40% (2/5) pts had significant reductions (83% and 38%) in TP53 mut VAF. The regimen was well tolerated with no pts stopping therapy due to adverse effects (AE) . AE included G3/G4 neutropenia (80%), G1 thrombocytopenia (40%), nausea (20%), fatigue (20%), lower extremity edema (20%), pneumonia (60%), and neutropenic fever (20%) with a median of 1 unplanned hospitalization per pt during follow-up. 60% (3/5) pts remain in CR on continued therapy for a median of 7.8 mo [7.2-9.4] thus far. One pt underwent allogeneic stem cell transplantation, however, died 11.4 mo after conditioning due to transplant related mortality. The R/R pt died after being lost to follow-up 2.9 mo after therapy initiation. No pt had measurable relapse during follow-up. Combination weekly Ven with subcutaneous low-dose Dec is well tolerated yielding high rates of clinical and molecular response in pts with TP53mut MDS/AML. Although small, this case-series extends previous clinical trial proof-of-activity of non-cytotoxic DNMT1-targeting to a high-risk, poor PS, historically chemorefractory patient population. The regimen allowed frequent, sustained exposure to therapy often not possible with standard HMA/Ven regimens. Figure 1 Figure 1. Disclosures Shastri: Kymera Therapeutics: Research Funding; Guidepoint: Consultancy; GLC: Consultancy; Onclive: Honoraria. Gritsman: iOnctura: Research Funding. Feldman: Glycomimetics: Current Employment, Current holder of stock options in a privately-held company. Verma: Celgene: Consultancy; Acceleron: Consultancy; Novartis: Consultancy; Stelexis: Consultancy, Current equity holder in publicly-traded company; Eli Lilly: Research Funding; Curis: Research Funding; Medpacto: Research Funding; Incyte: Research Funding; GSK: Research Funding; BMS: Research Funding; Stelexis: Current equity holder in publicly-traded company; Throws Exception: Current equity holder in publicly-traded company. Saunthararajah: EpiDestiny: Consultancy, Current holder of individual stocks in a privately-held company, Membership on an entity's Board of Directors or advisory committees, Patents & Royalties.

Pre-clinical and clinical data suggest that the bone marrow (BM) environment provides breast cancer (BC) cells a protective haven against chemotherapeutic insult, endocrine therapies, and immune recognition. Novel agents that intercept cross-talk between BC cells and the host could therefore improve the depth of response to therapies and potentially increase overall survival in metastatic BC. We have previously shown that bone metastatic BC cells reside in perivascular niches expressing high levels of SDF-1α (CXCL12) and E-selectin, two molecules for which emerging data have demonstrated a significant role in metastatic BC progression. Our prior pre-clinical studies have shown that E-selectin inhibition specifically prevents circulating BC cells from homing to the BM, whereas CXCR4 blockade mobilizes micrometastases from the marrow into circulation, where they may be sensitized to chemotherapeutic cell kill. Given the normal role of these molecules in host immune responses, E-selectin/CXCR4 blockade has additional potential to impact the tumor immune microenvironment. GMI-1359 is a small molecule, glycomimetic compound with dual inhibitory activity against E-selectin and CXCR4. We hypothesize that GMI-1359 can block E-selectin and CXCR4 binding to E-selectin ligands and SDF-1, disrupting the protective effects of the bone microenvironment on tumor cells. A single-center, phase 1b, open-label, single and multiple ascending dose study (NCT04197999) is therefore evaluating GMI-1359 in patients with HR+ metastatic breast cancer with bony metastases who are stable or minimally progressive on endocrine therapy, with or without a CDK4/6 inhibitor. To date, 2 patients have been enrolled and received single monthly doses of 3.5, 5.0 and 7.0 mg/kg followed by 3 daily doses of 7 mg/kg. Both patients have completed treatment with no dose limiting toxicities observed. Coincident with GMI-1359 administration at all dose levels, we observed mobilization of CD34+ cells coupled with a reduction in elevated serum sE-selectin levels, demonstrating the dual functionality of the compound. Initial peripheral blood immunophenotype data on one patient revealed a redistribution of myeloid derived suppressor cells and a shift in macrophage polarization from M2 to M1. Notably, we observed similar immune alterations in ongoing preclinical studies in the E0771 syngeneic BC mouse model. We found that orthotopically-engrafted mice treated with single agent 1359 had a significant increase in the ratio of CD8/Tregulatory cells isolated from the primary tumor and BM. We also observed a decrease in primary tumor M-MDSCs and lung metastasis-associated macrophages. In summary, our preliminary clinical data suggest that GMI-1359 is well-tolerated and elicits on-target effects expected from disruption of the host microenvironment. Ongoing clinical and preclinical work will define the efficacy of this strategy to enhance responses to chemo and immune therapies. Citation Format: P. Kelly Marcom, Trevor T. Price, Andrew S. Murray, William E. Fogler, John L. Magnani, Helen Thackray, Eric Feldman, Dorothy Sipkins. Development of GMI-1359, a novel agent targeting tumor-microenvironment cross-talk in bone metastatic cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2021; 2021 Apr 10-15 and May 17-21. Philadelphia (PA): AACR; Cancer Res 2021;81(13_Suppl):Abstract nr CT144.

Purpose Arsenic trioxide (ATO) is a highly effective agent for the treatment of acute promyelocytic leukemia (APL). QT interval prolongation is common with ATO and can pose a barrier to effective administration. The objective of this study was to characterize the prevalence, management, and clinical consequences of QT prolongation in a large cohort of patients treated with ATO. Patients and Methods We analyzed 3,011 electrocardiograms from 113 patients with non-APL acute myeloid leukemia and myelodysplastic syndrome who were treated on a previously reported clinical trial. QT intervals were assessed using four different correction formulas, and data were correlated with clinical parameters and treatment with ATO. Results There were no clinically significant cardiac events in the study population. Of those receiving ATO therapy, 29 patients (26%) had rate-uncorrected QT values above 470 ms and 13 (12%) had values exceeding 500 ms. With the commonly used Bazett rate correction formula, 102 patients (90%) had QTc greater than 470 ms, including 74 (65%) above 500 ms. By using alternative rate correction formulas, only 24% to 32% of patients had rate-corrected QT intervals above 500 ms. Conclusion QT interval prolongation is common with ATO treatment, but clinically significant arrhythmias are rare and can be avoided with appropriate precautions. Use of the Bazett correction may result in unnecessary interruptions in ATO therapy, and alternative rate correction formulas should be considered for routine electrocardiographic monitoring.

BACKGROUND CPX-351 is a liposome-encapsulated fixed-molar-ratio formulation of cytarabine and daunorubicin that exploits molar ratio–dependent drug-drug synergy to enhance antileukemic efficacy. METHODS This phase II study randomized 125 patients 2:1 to CPX-351 or investigators' choice of first salvage chemotherapy. Patients with acute myeloid leukemia (AML) in first relapse after initial Complete Remission (CR) lasting ≥1 month were stratified per the European Prognostic Index (EPI) into favorable, intermediate, and poor-risk groups based on duration of first CR, cytogenetics, age, and transplant history. Control salvage treatment was usually based on cytarabine and anthracycline, often with 1 or more additional agents. Survival at 1 year was the primary efficacy end point. RESULTS Patient characteristics were well balanced between the 2 study arms. Improvements in efficacy outcomes were observed following CPX-351, but did not meet prospectively defined statistical criteria for 1-year survival improvement in the overall population. Subset analyses of the EPI-defined poor-risk strata demonstrated higher response rates (39.3% vs 27.6%) and improvements in event-free survival (HR, 0.63; P = .08) and overall survival (HR, 0.55; P = .02). Also, 60-day mortality was lower in the CPX-351 study arm for poor-risk patients (16.1% vs 24.1%). CONCLUSIONS Taken together, the data suggest possible improved outcomes in CPX-351-treated first relapse AML patients with EPI-defined poor-risk disease. Cancer 2015;121:234–42. © 2014 American Cancer Society.

CPX-351 is a liposomal formulation of cytarabine:daunorubicin designed to deliver synergistic drug ratios to leukemia cells. In this phase 2 study, newly diagnosed older acute myeloid leukemia (AML) patients were randomized 2:1 to first-line CPX-351 or 7+3 treatment. The goal was to determine efficacy and identify patient subgroups that may benefit from CPX-351 treatment. Response rate (complete remission + incomplete remission) was the primary end point, with event-free survival (EFS) and overall survival (OS) as secondary end points. The 126 patients entered were balanced for disease and patient-specific risk factors. Overall, CPX-351 produced higher response rates (66.7% vs 51.2%, P = .07), meeting predefined criteria for success (P.1). Differences in EFS and OS were not statistically significant. A planned analysis of the secondary AML subgroup demonstrated an improved response rate (57.6% vs 31.6%, P = .06), and prolongation of EFS (hazard ratio [HR] = 0.59, P = .08) and OS (HR = 0.46, P = .01). Recovery from cytopenias was slower after CPX-351 (median days to absolute neutrophil count ≥1000: 36 vs 32; platelets100 000: 37 vs 28) with more grade 3-4 infections but without increase in infection-related deaths (3.5% vs 7.3%) or 60-day mortality (4.7% vs 14.6%), indicating acceptable safety. These results suggest a clinical benefit with CPX-351, particularly among patients with secondary AML, and provide the rationale for a phase 3 trial currently underway in newly diagnosed secondary AML patients. This study is registered at Clinicaltrials.gov as #NCT00788892.

There is no effective treatment for relapsed/refractory acute myeloid leukemia (AML) or myelodysplastic syndrome (MDS). We conducted a phase I dose escalation trial of SAR103168, a novel multi-targeted kinase inhibitor with activity against the Src kinase family, the BCR-Abl kinase and several angiogenic receptor kinases. Twenty-nine patients 18-83 years old were treated with SAR103168. Pharmacokinetics was characterized by plasma peak concentration (Cmax) at the end of the infusion, followed by a biphasic decline in the elimination profile. Adverse events were as expected for the patient population and there were no individual toxicities specific to SAR103168. Due to the unpredictable nature of drug exposure, the sponsor decided to discontinue the study prior to reaching the maximum tolerated dose.

Background Binding of E-selectin (E-sel) to sialyl Lex, the E-sel ligand, on the leukemic cell surface activates cell survival pathways and promotes chemotherapy resistance in AML. Higher expression of E-sel ligand is associated with relapse and poor survival. Uproleselan (GMI-1271), a novel E-selectin antagonist, disrupts cell survival pathway activation, enhances chemotherapy response and protects from toxicity such as mucositis with improved survival in vivo. Preclinical data support combination of uproleselan with chemotherapy improves response without additional toxicity. A phase 1/2 study (NCT02306291) of uproleselan added to chemotherapy (mitoxantrone, etoposide, cytarabine, MEC) in R/R AML showed promising outcomes at the recommended phase 2 dose (RP2D), including a CR/CRi rate of 41% and median OS of 8.8 m (95% CI 5.7-11.4). 11/16 (69%) evaluable patients were MRD negative (DeAngelo et al ASH 2018). Patients with sufficient expression of the appropriate E-selectin ligand (the target of the E-selectin inhibitor) exhibited higher CR/CRi rate and longer survival. Median OS for Leukemic blasts/E-sel ligand ≥10% vs leukemic blasts/E-sel ligand Study Design and Methods This study is a global, randomized, double-blind, placebo-controlled phase 3 registration trial. Major Eligibility Criteria ≥18 to ≤75 years old Primary refractory AML, first or second relapse of AML Prior transplant (HSCT) is allowed Must be medically eligible for chemotherapy ECOG performance status ≤2 Study treatment and endpoints Treatment is MEC or FAI (fludarabine, cytarabine, idarubicin) induction with blinded study drug (uproleselan/placebo at 1:1 ratio) administered 1 day prior (sentinel dose) and then BID through 2 days post chemotherapy. Consolidation (HiDAC/IDAC) with uproleselan/placebo (same assignment) up to 3 cycles is allowed. The primary endpoint is overall survival; key secondary endpoints include the incidence of severe oral mucositis during induction and CR/CRh rate. Measurable residual disease, event free survival, safety, and pharmacokinetics will also be evaluated. In addition, the relationship between E-sel ligand expression on leukemic cells in the bone marrow and clinical outcomes in AML will be determined. Statistical methods The phase III primary endpoint will compare overall survival between the treatment arms using a stratified log-rank test. Stratification factors will be age group, disease status, backbone chemotherapy and prior transplant status. Median time to event values will be estimated using the Kaplan-Meier method. The study is powered to detect an improvement in median OS using a log-rank test (HR= 0.68, one-sided 0.025 type I error rate). A hierarchical testing procedure will be used to assess the statistical significance of the key secondary analyses, incidence of severe oral mucositis and remission rate (CR/CRh, CR). Study status This trial is expected to enroll 380 patients across approximately 9 countries in North America, Europe, and Australia. The first patient was enrolled in November 2018. Disclosures DeAngelo: Novartis: Consultancy, Patents & Royalties: Royalty, Research Funding; Takeda Pharmaceuticals: Consultancy; Jazz Pharmaceuticals Inc: Consultancy; Incyte: Consultancy; Amgen: Consultancy; Pfizer: Consultancy; Abbvie: Research Funding; GlycoMimetics: Research Funding; Celgene: Consultancy; Blue Print Medicines: Consultancy, Research Funding; Shire: Consultancy. Erba:Agios: Consultancy, Speakers Bureau; Novartis: Consultancy, Research Funding, Speakers Bureau; Daiichi Sankyo: Consultancy, Research Funding; Novartis: Consultancy, Research Funding, Speakers Bureau; MacroGenics: Consultancy, Other: Lecture fees, Research Funding; MacroGenics: Consultancy, Other: Lecture fees, Research Funding; Jazz Pharmaceuticals: Consultancy, Speakers Bureau; Jazz Pharmaceuticals: Consultancy, Speakers Bureau; Seattle Genetics: Consultancy; Seattle Genetics: Consultancy; GlycoMimetics: Consultancy, Other: Chair, data and safety monitoring board, Research Funding; Amgen: Consultancy; Amgen: Consultancy; Pfizer: Consultancy; Pfizer: Consultancy; Celgene: Consultancy, Other: chair, AML Registry Scientific Steering Committee, Speakers Bureau; Celgene: Consultancy, Other: chair, AML Registry Scientific Steering Committee, Speakers Bureau; Daiichi Sankyo: Consultancy, Research Funding; GlycoMimetics: Consultancy, Other: Chair, data and safety monitoring board, Research Funding; Covance: Other: Fees for serving as chair on an independent review board for AbbVie Phase III studies; Covance: Other: Fees for serving as chair on an independent review board for AbbVie Phase III studies; AbbVie: Consultancy, Other: Chair, IRC for phase III studies, Research Funding; AbbVie: Consultancy, Other: Chair, IRC for phase III studies, Research Funding; Agios: Consultancy, Speakers Bureau; Incyte: Consultancy, Speakers Bureau; Incyte: Consultancy, Speakers Bureau; Astellas Pharma: Consultancy; Astellas Pharma: Consultancy; ImmunoGen: Consultancy, Research Funding; ImmunoGen: Consultancy, Research Funding. Jonas:AbbVie, Amgen, Celgene, GlycoMimetics, Jazz, Pharmacyclics, Tolero: Consultancy, Membership on an entity's Board of Directors or advisory committees; AbbVie, Accelerated Medical Diagnostics, AROG, Celgene, Daiichi Sankyo, Esanex, Forma, Genentech/Roche, GlycoMimetics, Incyte, LP Therapeutics, Pharmacyclics: Research Funding; AbbVie, Amgen, GlycoMimetics: Other: Travel expenses. O'Dwyer:AbbVie: Consultancy; GlycoMimetics Inc: Research Funding; Janssen: Membership on an entity's Board of Directors or advisory committees, Research Funding; BMS: Research Funding; Onkimmune: Equity Ownership, Membership on an entity's Board of Directors or advisory committees, Research Funding. Marlton:Celgene: Honoraria, Membership on an entity's Board of Directors or advisory committees; Roche: Honoraria, Membership on an entity's Board of Directors or advisory committees; AbbVie: Honoraria, Membership on an entity's Board of Directors or advisory committees; Novartis: Membership on an entity's Board of Directors or advisory committees; Janssen: Membership on an entity's Board of Directors or advisory committees; Astellas: Membership on an entity's Board of Directors or advisory committees. Liesveld:Abbvie: Membership on an entity's Board of Directors or advisory committees; Onconova: Other: Data safety monitoring board. Bhatnagar:Novartis and Astellas: Consultancy, Honoraria; Cell Therapeutics, Inc.: Other: Research support; Karyopharm Therapeutics: Other: Research support. Uy:Astellas: Consultancy; Pfizer: Consultancy; Curis: Consultancy; GlycoMimetics: Consultancy. Cull:Amgen: Other: Travel, accommodation ; AbbVie: Other: Travel, accommodation; Glycomimetics: Other: Travel, accommodation. Armstrong:GlycoMimetics: Consultancy. Fogler:GlycoMimetics Inc: Employment, Equity Ownership. Chen:GlycoMimetics: Employment. Magnani:GlycoMimetics Inc: Employment, Equity Ownership. Thackray:GlycoMimetics Inc: Employment. Feldman:GlycoMimetics Inc: Employment. Advani:Macrogenics: Research Funding; Glycomimetics: Consultancy, Research Funding; Kite Pharmaceuticals: Consultancy; Amgen: Research Funding; Abbvie: Research Funding; Pfizer: Honoraria, Research Funding. Becker:Accordant Health Services/Caremark: Consultancy; AbbVie, Amgen, Bristol-Myers Squibb, Glycomimetics, Invivoscribe, JW Pharmaceuticals, Novartis, Trovagene: Research Funding; The France Foundation: Honoraria.

Leukemic myeloblasts expressing E-selectin ligand (E-sel ligand) adhere to E-selectin on bone marrow endothelium resulting in environment-mediated drug resistance (EMDR). Uproleselan, a potent E-selectin inhibitor, disrupts the adhesion of AML cells in the bone marrow, re-sensitizing blasts to the cytotoxic effects of chemotherapy. Retrospective data demonstrated that E-sel ligand expression in AML patients is higher in relapsed disease compared to newly diagnosed AML, is more commonly seen in biologically adverse risk patients, and is present on leukemic stem cells (Chien et al ASH 2018). Preliminary data from a phase 1-2 trial of uproleselan combined with mitoxantrone, etoposide, cytarabine (MEC) chemotherapy in R/R AML demonstrated enhanced survival in patients with E-sel ligand expression on AML cells of > 10% compared to lower levels (DeAngelo et al ASH 2018). In order to more fully understand the relationship of E-sel ligand to the activity of uproleselan, we examined the clinical variables of patients with both high (> 10%) and low E-sel ligand levels in comparison to the total population of patients treated on the phase 1-2 trial. Uproleselan, combined with MEC chemotherapy was studied in 66 patients with relapsed and/or refractory AML. The expression level of E-sel ligand on the surface of AML cells (blasts/leukemic stem cells (LSCs)) in the bone marrow was measured by a flow cytometric assay using the HECA 452 antibody that recognizes a functional trisaccharide domain shared by sialyl Lea and sialyl Lex and known to bind to E-selectin. Data on E-sel ligand was available in 36 patients at study entry in the phase 1-2 study and E-sel ligand was detectable on blasts in all patients. E-sel ligand on LSCs was demonstrated at levels ≥ 10% in 22 patients (61%) and at levels < 10 % in 14 patients (39%). Overall, the clinical characteristics confirmed a highly resistant population of R/R AML patients (see table) with 79% categorized as either poor risk by the European Prognostic Index (EPI) for first salvage therapy or ≥ second salvage, with an expected 1 year survival of less than 20% (Breems et al JCO 2005, Giles et al Cancer 2005). Although the sample size was small (n=36), substantially more patients with high E-sel ligand had achieved an initial remission and were in relapse (68%) whereas low E-sel ligand patients were more likely to be primary refractory (57%) (p=0.17). Patients with high E-sel ligand were more likely to have adverse ELN risk disease (55%) compared to low E-sel ligand patients (28%) (p=0.053). These data are consistent with previous findings demonstrating that higher E-sel ligand expression contributes to clinical chemotherapy resistance, particularly increasing the risk of relapse, whereas alternative resistance mechanisms may more commonly contribute to primary resistance. Importantly, the 45% response rate and 12.7 months median overall survival (OS) in the high E-sel ligand patients suggests that E-selectin inhibition by uproleselan contributed to their significantly improved outcomes when compared to the historically dismal outcomes with standard of care alone in these poor risk R/R AML patients. Table. Disclosures DeAngelo: Incyte Corporation: Consultancy; Celgene Corporation: Consultancy; Pfizer, Inc.: Consultancy; GlycoMimetics: Research Funding; AbbVie, Inc.: Research Funding; Takeda Pharmaceuticals: Consultancy; Shire: Consultancy; Amgen: Consultancy; Blue Print Medicines: Consultancy, Research Funding; Jazz Pharmaceuticals, Inc.: Consultancy; Novartis Pharmaceuticals Corporation: Consultancy, Research Funding. Jonas:AbbVie, Accelerated Medical Diagnostics, AROG, Celgene, Daiichi Sankyo, Esanex, Forma, Genentech/Roche, GlycoMimetics, Incyte, LP Therapeutics, Pharmacyclics: Research Funding; AbbVie, Amgen, Celgene, GlycoMimetics, Jazz, Pharmacyclics, Tolero: Consultancy, Membership on an entity's Board of Directors or advisory committees; AbbVie, Amgen, GlycoMimetics: Other: Travel expenses. Liesveld:Abbvie: Membership on an entity's Board of Directors or advisory committees; Onconova: Other: Data safety monitoring board. Advani:Pfizer: Honoraria, Research Funding; Glycomimetics: Consultancy, Research Funding; Amgen: Research Funding; Kite Pharmaceuticals: Consultancy; Abbvie: Research Funding; Macrogenics: Research Funding. Marlton:Celgene: Honoraria, Membership on an entity's Board of Directors or advisory committees; Roche: Honoraria, Membership on an entity's Board of Directors or advisory committees; AbbVie: Honoraria, Membership on an entity's Board of Directors or advisory committees; Novartis: Membership on an entity's Board of Directors or advisory committees; Janssen: Membership on an entity's Board of Directors or advisory committees; Astellas: Membership on an entity's Board of Directors or advisory committees. O'Dwyer:Onkimmune: Equity Ownership, Membership on an entity's Board of Directors or advisory committees, Research Funding; AbbVie: Consultancy; Janssen: Membership on an entity's Board of Directors or advisory committees, Research Funding; GlycoMimetics Inc: Research Funding; BMS: Research Funding. Fogler:GlycoMimetics Inc: Employment, Equity Ownership. Magnani:GlycoMimetics Inc: Employment, Equity Ownership. Chen:GlycoMimetics: Employment. Feldman:GlycoMimetics Inc: Employment. Thackray:GlycoMimetics Inc: Employment. Becker:AbbVie, Amgen, Bristol-Myers Squibb, Glycomimetics, Invivoscribe, JW Pharmaceuticals, Novartis, Trovagene: Research Funding; Accordant Health Services/Caremark: Consultancy; The France Foundation: Honoraria.

TPS7071 Background: The CD33 antigen is expressed on myeloblasts in approximately 75% of patients with myelodysplastic syndromes (MDS) and is also expressed on immunosuppressive myeloid-derived suppressor cells (MDSCs) that are prevalent in MDS. AMV564 is a novel bivalent, bispecific (2:2) T-cell engager that binds both CD33 and the invariant CD3ε on T-cells with strong avidity. AMV564 has significant cytotoxic activity against CD33-postive cells, including MDSCs, in animal models, in vitro studies, and in patients (Reusch et al. Clin Can Res 2016 and List et al. ASH 2017). Preliminary results from the phase 1 acute myeloid leukemia (AML) trial have demonstrated safety and activity in patients with AML arising from prior MDS (Westervelt et al. ASH 2018). Methods: AMV564-201 is an open label, phase 1, multicenter, dose-escalation with expansion trial of AMV564 in patients with intermediate-2 or high-risk MDS who are refractory to or relapsed from hypomethylating agents (HMAs) or intensive chemotherapy. The key objectives of the dose-escalation stage of the study are to characterize the safety and tolerability of AMV564, identify a maximum tolerated dose and/or a dose-schedule to evaluate in the dose expansion portion of the study. In the dose expansion stage of the study, the safety and tolerability of AMV564 will be further characterized in addition to a preliminary assessment of efficacy. Other objectives include characterization of AMV564 pharmacokinetics, pharmacodynamics, and immunogenic potential. Approximately 80 patients with intermediate-2 or high-risk MDS will be enrolled. The Dose Escalation Stage will include up to approximately 30 patients, depending on the dose at which the MTD is determined for each schedule, and approximately 50 additional patients will be enrolled in the Expansion Stage. AMV564 will be administered daily as a continuous intravenous (CIV) infusion over a period of 24 hours for 14 days in each cycle. Each cycle will be approximately 4 weeks. A lead-in dose regimen will be utilized for all patients treated at dose levels at or above 50 mcg/day. Patients will receive up to 4 cycles of AMV564 treatment at the assigned dose level. Clinical trial information: NCT03516591.

CD33 is expressed on the surface of myeloblasts in 85 to 90% of patients with AML and represents a promising target regardless of age, risk factors, or underlying mutational heterogeneity. SGN-CD33A is an antibody-drug conjugate (ADC) composed of an anti-CD33 antibody with engineered cysteines enabling uniform site-specific conjugation, conjugated to a pyrrolobenzodiazepine (PBD) dimer which binds DNA with high intrinsic affinity. The antibody and PBD dimer are conjugated via a cleavable dipeptide linker that is highly stable in circulation. Upon binding to the cell surface, SGN-CD33A is internalized and transported to the lysosomes where PBD dimer is released via proteolytic cleavage of the linker and diffuses inside the cell. PBD dimer crosslinks DNA, overwhelms DNA repair mechanisms, and triggers a cascade of events leading to cell death. SGN-CD33A is active as a single agent against a broad panel of primary AML samples and in multidrug-resistant preclinical models of AML (Sutherland 2013). Additionally, significant synergism in tumor cell killing was demonstrated in cytotoxicity assays when SGN-CD33A was combined with cytarabine, azacitidine, or decitabine (Sutherland 2014). Consistent with these observations, greater antitumor activity and reduced tumor growth were observed with these agents in combination with a single noncurative dose of SGN-CD33A in mouse xenograft models of multidrug resistant AML. The synergism with hypomethylating agents was associated with upregulation of CD33 expression on the cell surface of the AML cells as well as greater activation of the DNA damage sensor and apoptoticpathways. A first-in-human, phase 1, dose-escalation study of SGN-CD33A is ongoing to investigate the safety, tolerability, pharmacokinetics, and antitumor activity of SGN-CD33A in patients with CD33-positive AML (NCT# 01902329). Patients must have either relapsed disease following initial complete remission (CR) of >3 months, or have declined conventional induction/consolidation. SGN-CD33A is administered outpatient IV every 3 weeks for up to 4 cycles (Part A), followed by optional maintenance treatment for patients achieving a CR/CRi (Part B). Investigator assessment of response is per IWG criteria (Cheson 2003). Another arm of the study will investigate the safety of SGN-CD33A in combination with either azacitidine or decitabine. Data have been reported on the first 56 patients who received SGN-CD33A as a single agent at doses ranging from 5−60 mcg/kg (presented by E. Stein at ASH 2014). Median age of patients was 75 years (range 27−86) and approximately 90% of patients had an ECOG performance score of 1. About half of the patients had received prior intensive therapy for AML, while the other half had declined intensive therapy. The most common adverse events considered related to SGN-CD33A included febrile neutropenia, fatigue, thrombocytopenia, anemia, and pyrexia. The 30-day mortality rate at the time of data presentation was 2% (1 patient whose death was not considered associated with SGN-CD33A). Preliminary pharmacokinetic data demonstrate rapid clearance of the ADC, suggesting target-mediated drug disposition. Among 52 patients evaluated for antitumor activity, 9 achieved CR or CR with incomplete hematologic recovery (CRi), 11 patients had clearance of blasts in their bone marrow (morphologic leukemia-free state, MLFS), and 29 patients had residual blasts in the bone marrow. The CR/CRi rate at 40 mcg/kg was 29% (5/17). The ongoing phase 1 study is evaluating SGN-CD33A as monotherapy and in combination with hypomethylating agents. Efforts are ongoing to refine a recommended dosing regimen for future study. Also enrolling is a phase 1b study of SGN-CD33A in combination with 7+3 chemotherapy in the frontline treatment of AML (NCT# NCT02326584). To date, preclinical data combined with emerging clinical safety and antitumor activity data form a foundation for the development of SGN-CD33A as a novel, targeted CD33-directed therapy for the treatment of AML and potentially other myeloid malignancies. Citation Format: Dana A. Kennedy, Stephen C. Alley, Baiteng Zhao, Eric J. Feldman, Megan O'Meara, May Sutherland. SGN-CD33A: Preclinical and phase 1 interim clinical trial results of a CD33-directed PBD dimer antibody-drug conjugate for the treatment of acute myeloid leukemia (AML). [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr DDT02-04. doi:10.1158/1538-7445.AM2015-DDT02-04

This phase I study evaluated the maximal tolerated dose of CPX-351 when administered sequentially with allogeneic hematopoietic stem cell transplantation (HSCT) in patients with refractory acute leukemia. CPX-351 is a novel liposomal formulation that combines cytosine arabinoside (ara-c) and daunorubicin in a fixed molar ratio of 5:1. Patients in cohorts of 3 were treated with CPX-351 followed by fludarabine and busulfan (Bu/Flu) conditioning at 4-week (schedule A) or 3-week (schedule B) intervals. CPX-351 doses were escalated in 20-U/m2 increments starting at 60 U/m2 for 3 doses. Of the 36 patients enrolled, 29 were able to undergo HSCT, and the other 7 (the majority on schedule A) did not proceed to HSCT because of rapid disease progression. The maximal tolerated dose of CPX-351 was not reached at the 120 U/m2 × 3 dose level. All 29 patients who proceeded to HSCT demonstrated adequate neutrophil and platelet engraftment. The median follow-up on the study for all 36 patients was 205 days (range, 20 to 996 days). The 1-year cumulative incidence of relapse for the 36 patients was 60.1% (95% confidence interval [CI], 43.4% to 77.3%), and that of nonrelapse mortality was 23.8% (95% CI, 10.9% to 47.4%). The 1-year overall survival and leukemia-free survival were 37% (95% CI, 21% to 53%) and 27% (95% CI, 13% to 43%), respectively. Our data suggest that a phase II trial should incorporate CPX-351 120 U/m2 × 3 dosing on schedule B. Patients with good performance status and those who achieve effective cytoreduction from CPX-351 derived the greatest benefit.

Summary Background Tosedostat is a novel oral aminopeptidase inhibitor with clinical activity in a previous phase 1–2 study in elderly patients with relapsed or refractory acute myeloid leukaemia (AML). We aimed to compare two dosing regimens of tosedostat. Methods In this randomised phase 2 study, patients aged 60 years or older with AML that had relapsed after a first complete remission lasting less than 12 months, or had achieved no previous complete remission, were randomly assigned (1:1) to receive as first salvage tosedostat 120 mg once daily for 6 months or 240 mg once daily for 2 months followed by 120 mg for 4 months. Randomisation was by block method via an interactive web response system using a randomisation schedule generated by an external vendor, with no stratification. The study was open label. The primary endpoint was the proportion of patients who obtained a complete remission or complete remission with incomplete platelet recovery. Analyses included all patients randomly assigned to treatment groups who received at least one oral dose of tosedostat. The study is registered with ClinicalTrials.gov, number NCT00780598. Findings 38 patients were randomly assigned to receive tosedostat 120 mg and 38 to receive the tosedostat 240 mg to 120 mg regimen. 38 patients in the 120 mg group and 35 in the 240 mg to 120 mg group received tosedostat. Seven patients (10%) had complete remission or complete remission with incomplete platelet recovery: two (5%) in the 120 mg group and five (14%) in the 240 mg to 120 mg group. The most common grade 3 or worse adverse events were febrile neutropenia (11 [29%] patients in the 120 mg group and ten [29%] of the 240 mg to 120 mg group), thrombocytopenia (eight [21%] and eight [23%] patients), fatigue (seven [18%] and eight [23%] patients), dyspnoea (five [13%] and seven [20%] patients), and pneumonia (four [11%] and six [17%] patients). There were five fatal adverse events deemed to be treatment-related: three in the 120 mg group and two in the 240 mg to 120 mg group. The events were acute hepatitis, respiratory failure, pneumonia, atrial fibrillation, and left ventricular dysfunction. Interpretation Tosedostat, at either dose schedule, has activity in older patients with relapsed or refractory AML. Additional studies of tosedostat including combination with hypomethylating agents and low-dose cytarabine in patients with high-risk myelodysplastic syndromes and AML are ongoing or planned. Funding Chroma Therapeutics.

Treatment options for older patients with acute myeloid leukemia (AML) and for patients with relapsed/refractory AML are limited, and outcomes are poor. Decitabine, a hypomethylating agent, is active in patients with myelodysplastic syndrome (MDS) and AML, but its optimal dose and schedule are unknown. We report the efficacy and safety of repeated 10-day cycles of decitabine 20 mg/m(2) administered intravenously over 1 h in 52 newly diagnosed and 102 relapsed/refractory patients. Repeated 10-day cycles of decitabine produced a complete response (CR) in 40% of newly diagnosed older patients with AML, many of whom had adverse prognostic features. The median overall survival (OS) was 318 days but there was prolonged survival in responders of 481 days. Relapsed/refractory patients had a CR rate of 15.7% with a median OS of 177 days. Extramedullary toxicity was mild and the regimen was well tolerated for ongoing post-remission, outpatient maintenance cycles. Responses were durable for over 1 year.

While antibody-based therapies have emerged as clinically effective approaches for several hematologic and solid malignancies, they have not played a significant role to date in the treatment of acute myeloid leukemia (AML). More recently, improvements in antibody-drug conjugate technology, bispecific antibodies, as well as identification of novel AML antigens have re-invigorated enthusiasm for antibody-based therapies for AML. This review describes experiences with former and existing antibody-based therapies for AML, including unconjugated antibodies, antibody-drug conjugates (ADCs), radio-labelled antibodies, and immune-engaging antibodies, and discusses the promise and challenges associated with each.

This study compares outcomes of low-intensity versus standard-intensity induction strategies for older patients with acute myeloid leukemia at the Weill Cornell Leukemia Program. From 1999 to 2009, 298 adults ≥60 years with AML underwent induction chemotherapy with low-intensity and standard-intensity regimens, based on physician and patient preferences and investigational protocol availability. Overall, 33% of the cohort achieved complete remission with initial treatment, 23% with low-intensity induction and 53% with standard-intensity induction (P < 0.0001). The median overall survival was 6.5 months and there was no significant difference in overall survival between patients initially treated with a low-intensity regimen compared to those receiving standard-intensity induction. There were no differences in 30- or 60-day mortality between the two groups.

Thirty consecutive patients underwent hematopoietic stem cell transplantation for myelofibrosis (MF) at our institution. The median age at the time of transplant was 49 (range, 18-68) years, 74% of patients had advanced Dynamic International Prognostic Scoring System (DIPSS) scores, and 83% received reduced-intensity conditioning.With a long follow-up of our patients, we analyzed disease and transplant variables that contributed to engraftment and outcomes.Neutrophil engraftment was achieved in 27 patients (90%) at a median time of 15 (range, 10-44) days, and 19 patients (63%) achieved platelet recovery at a median time of 18 (range, 8-100) days. Splenomegaly was associated with poor neutrophil engraftment (subdistributional hazard ratio [SHR], 0.42; 95% confidence interval [CI], 0.21-0.83; P = .01) and platelet engraftment (SHR, 0.18; 95% CI, 0.07-0.48; P .001). Increased levels of lactate dehydrogenase (LDH) was associated with poor platelet engraftment (SHR, 0.39; 95% CI, 0.16-0.94; P = .04). The median follow-up for surviving patients was 49 (range, 3-155) months. The 1-year cumulative incidence of nonrelapse mortality (NRM) and relapse were respectively, 57% (95% CI, 29%-76%) and 25% (95% CI, 7%-48%). Increased levels of LDH was associated with high NRM (SHR, 2.82; 95% CI, 1.08-7.35; P = .03). The 4-year overall survival (OS) and relapse-free survival (RFS) were 44% (95% CI, 29%-67%) and 37% (95% CI, 23%-61%), respectively. In the multivariable model, splenomegaly and Eastern Cooperative Oncology Group (ECOG) performance status (PS)1 were associated with worse OS (hazard ratio [HR], 5.40; 95% CI, 1.19-24.56); P = .03) and RFS (HR, 3.78; 95% CI, 1.01-14.06; P .05), respectively. ECOG PS1 was also associated with worse RFS (HR, 5.00; 95% CI, 1.31-19.14; P = .02). In this patient group with advanced disease, DIPPS score, Lille score, Janus-Associated Kinase V617F (JAK2 V617F) mutation status, and donor type did not predict transplant outcome.We confirm curative potential, but high NRM of allogeneic transplant for advanced MF.

Patients with primary resistant and relapsed acute myeloid leukemia (AML) are rarely cured without undergoing allogeneic stem cell transplantation. What is currently debated is whether a trial of re-induction chemotherapy prior to transplantation is beneficial. Data from multiple retrospective analyses have shown that pretreatment variables are useful in predicting response to salvage chemotherapy. For patients unlikely to respond, re-induction attempts may be detrimental, leading to added organ toxicity and possible increased tumor resistance. Allogeneic transplantation in the setting of active disease is the alternative strategy. Multiple studies have demonstrated the feasibility of this approach, but cure rates have been low with the use of traditional transplant approaches. Newer strategies employing allogeneic transplantation earlier in patients with relapsed or refractory AML, as well as the incorporation of novel and effective antileukemic agents into the transplant conditioning regimen, may lead to better outcomes.

We conducted an open-label phase 1 study exploring the feasibility, safety, and biologic activity of epigenetic priming with decitabine before standard induction chemotherapy in patients with less-than-favorable risk of acute myelogenous leukemia (AML). We directly compared the clinical and DNA-hypomethylating activity of decitabine delivered at 20 mg/m2 by either a 1-hour infusion (Arm A) or a continuous infusion (Arm B) for 3, 5, or 7 days before a single, standard induction with infusional cytarabine (100 mg/m2 for 7 days) and daunorubicin (60 mg/m2 × 3 doses). Toxicity was similar to that of standard induction chemotherapy alone. Although we did not identify a maximum tolerated dose, there was more gastro-intestinal toxicity with 7 days of decitabine priming. Decitabine induced DNA hypomethylation at all dose levels and there was a trend toward greater hypomethylation in CD34+ bone marrow cells when decitabine was delivered by a short pulse (Arm A). Twenty-seven subjects (90%) responded to therapy: 17 with complete remission (57%) and 10 with partial remission (33%). Of the patients with partial remission to protocol treatment, 8 achieved remission to their next therapy, bringing the overall complete remission rate to 83%. We conclude that epigenetic priming of intensive chemotherapy can be safely delivered in an attempt to improve response rates. This trial was registered at www.clinicaltrials.gov as NCT00538876.

Some of the common non-random chromosomal abnormalities observed in patients with B lymphoblastic leukemia/lymphoma (B-ALL) are t(1;19)(q23;p13.3), t(4;11)(q21;q23), t(9;22)(q34;q11.2), and t(12;21...

Advanced myelodysplastic syndrome (MDS) carries a poor prognosis. In this phase I/II study, arsenic trioxide was combined with low-dose cytarabine in 49 previously untreated patients with intermediate-2 and high-risk MDS. Complete remission was achieved in 8 (17%) patients, including 3/14 (21%) with treatment-related disease, 4/31 (13%) with unfavorable cytogenetics and 2/36 (6%) with baseline poor performance status. Mortality within the first 4 weeks was 8%. The regimen was active and had a tolerable extramedullary toxicity profile, but it was cumbersome and intensive compared to other currently available treatments.

Purpose This phase I dose-escalation trial was performed to determine the maximum-tolerated dose, dose-limiting toxicities, and pharmacokinetics of CPX-351. Patients and Methods CPX-351 induction was administered on days 1, 3, and 5 by 90-minute infusion to 48 relapsed or refractory patients with acute myeloid leukemia (AML) or high-risk myelodysplasia. Doses started at 3 units/m2 with dose doublings in single-patient cohorts until a pharmacodynamic effect (treatment-related adverse events or reduction in bone marrow cellularity or blast count) was observed, followed by 33% escalations in three patient cohorts until dose-limiting toxicity (DLT) occurred. Results The maximum-tolerated dose was 101 units/m2. DLTs consisted of hypertensive crisis, congestive heart failure, and prolonged cytopenias. Adverse events were consistent with cytarabine and daunorubicin treatment. Response occurred at doses as low as 32 units/m2. Of 43 patients with AML, nine had complete response (CR) and one had CR with incomplete platelet recovery; of patients with acute lymphoblastic leukemia, one of three had CR. Eight CRs were achieved among the 31 patients with prior cytarabine and daunorubicin treatment. CR in AML occurred in five of 26 patients age ≥ 60 years and in five of 17 patients younger than age 60 years. Median half-life was 31.1 hours (cytarabine) and 21.9 hours (daunorubicin), with both drugs and their metabolites detectable > 7 days after the last dose. The targeted 5:1 molar ratio was maintained at all dose levels for up to 24 hours. Conclusion The recommended dose of CPX-351 for phase II study is 101 units/m2. Further exploration of efficacy and safety is ongoing in phase II trials in newly diagnosed and first-relapse patients with AML.

Background: AMV564 is a novel bivalent, bispecific (2x2) CD33/CD3 targeted immunotherapy that binds both CD33 and the invariant CD3ε on T-cell receptors with strong avidity, thus creating an immune synapse between CD33-expressing cells and T cells, initiating T-cell directed lysis of CD33 expressing cells, and inducing expansion, differentiation and proliferation of T cells. By design, AMV564 has reduced clearance and therefore has a longer half-life (t1/2) than monovalent, bispecific T-cell engagers. In preclinical investigations using both leukemic cell lines and primary cells from AML patients, AMV564 eliminated myeloid blasts with picomolar potency and broad activity independent of cytogenetic or molecular abnormalities, CD33 expression level, and disease stage, with no nonspecific activation of T cells (Reusch U et al. Clin Cancer Res 2016;22:5829-38). Methods: This is an ongoing Phase 1 study with a 3+3 dose-escalation design (NCT03144245). The primary objectives of this study are to characterize the safety, tolerability, and preliminary anti-leukemic activity of AMV564. Evaluation of pharmacokinetics (PK), cytokine changes, and immunophenotyping are secondary objectives. Key inclusion/exclusion criteria are: adults with relapsed and/or refractory AML after 1-2 prior induction regimens (with a standard anthracycline-based regimen or hypomethylating agent) and no more than 2 prior salvage regimens. AMV564 is administered by continuous intravenous infusion (CIV) for 14 consecutive days for up to 2 induction cycles. AMV564 and cytokine (IL2, IL4, IL6, IL8, IL10, TNF-α, and IFN-γ) concentrations were measured by validated immunoassays. T-cell activation was measured using flow cytometry to quantify T cells expressing CD25, CD38, CD69, or HLA-DR. Results: To date, 19 patients (10 male/9 female) with a median age of 72 years (range 24-84) have been enrolled in 6 dosing cohorts: 0.5, 1.5, 5.0, 15, 50, and 100 mcg/day. Thirteen patients (68%) had secondary AML and/or adverse cytogenetics, including 6 patients (32%) with a p53 mutation. Fifteen patients (79%) had received at least 1 prior salvage regimen and 11 (58%) had received prior intensive chemotherapy, including 6 patients (32%) who had received a high-dose (≥ 1 gm/m2) cytarabine-based regimen. Overall, 18 patients were evaluable for toxicity and response. No dose-limiting toxicity or treatment-related grade ≥ 3 adverse events (AE) were reported. Grade 2 CRS was observed in 1 patient (treated at 50 mcg/day) without a lead-in dose and was managed with drug interruption and 1 dose of tocilizumab. The patient was able to resume dosing and completed the full 14-day scheduled therapy without recurrence of CRS. Subsequent patients treated at 50 mcg/day and above were given a 15 mcg/day lead-in dose for 3 days followed by 11 days at the assigned dose level. The most common grade ≥ 3 treatment-emergent AE has been febrile neutropenia, reported in 39% (7/18) of patients and all considered unrelated to study drug. No patient has died within 30 days of treatment initiation. AMV564 PK was linear with a terminal t1/2 of 2-3 days. Plasma concentrations increased gradually, with times to steady-state concentration of 3-7 days. Marked increases in IL6 (peak concentration, 1.1 ng/mL), IL8 (1.5 ng/mL), and IL10 (0.3 ng/mL) cytokines were observed and increased numbers of activated T-cells were detected post-treatment. Reductions in bone marrow blasts, ranging from 13% to 91%, were observed in 12 of 18 evaluable patients including a partial response after cycle 1 in 1 patient at the 100 mcg/day dose level. Conclusions: AMV564 is well-tolerated and demonstrates anti-leukemic activity through T-cell engagement. AMV564 has a unique PK profile with a gradual increase in drug concentration and thus the potential for controlled T-cell activation. Disclosures Roboz: Daiichi Sankyo: Consultancy; Argenx: Consultancy; Sandoz: Consultancy; Aphivena Therapeutics: Consultancy; Cellectis: Research Funding; Argenx: Consultancy; Eisai: Consultancy; Celgene Corporation: Consultancy; Roche/Genentech: Consultancy; Jazz Pharmaceuticals: Consultancy; Otsuka: Consultancy; Roche/Genentech: Consultancy; Jazz Pharmaceuticals: Consultancy; Otsuka: Consultancy; AbbVie: Consultancy; Astex Pharmaceuticals: Consultancy; Celgene Corporation: Consultancy; Janssen Pharmaceuticals: Consultancy; AbbVie: Consultancy; Astex Pharmaceuticals: Consultancy; Bayer: Consultancy; Novartis: Consultancy; Sandoz: Consultancy; Novartis: Consultancy; Celltrion: Consultancy; Aphivena Therapeutics: Consultancy; Pfizer: Consultancy; Cellectis: Research Funding; Eisai: Consultancy; Orsenix: Consultancy; Celltrion: Consultancy; Bayer: Consultancy; Pfizer: Consultancy; Janssen Pharmaceuticals: Consultancy; Daiichi Sankyo: Consultancy; Orsenix: Consultancy. Cortes:Novartis: Consultancy, Research Funding; Astellas Pharma: Consultancy, Research Funding; Pfizer: Consultancy, Research Funding; Daiichi Sankyo: Consultancy, Research Funding; Arog: Research Funding. Lee:AstraZeneca: Consultancy; Clinipace: Consultancy; Karyopharm Therapeutics Inc: Consultancy; LAM Therapeutics: Research Funding; Amgen: Consultancy. Rettig:Amphivena Therapeutics: Research Funding; Novimmune: Research Funding. Han:Amphivena Therapeutics, Inc: Employment. Guenot:Amphivena Therapeutics, Inc: Employment. Feldman:Amphivena Therapeutics, Inc: Employment.

Purpose Mutations leading to constitutive activation of the FMS-like tyrosine kinase 3 receptor (FLT3) occur in blasts of 30% of patients with acute myeloid leukemia (AML). Midostaurin (PKC412; N-benzoylstaurosporin) is a multitargeted tyrosine kinase inhibitor, with demonstrated activity in patients with AML/myelodysplastic syndrome (MDS) with FLT3 mutations. Patients and Methods Ninety-five patients with AML or MDS with either wild-type (n = 60) or mutated (n = 35) FLT3 were randomly assigned to receive oral midostaurin at 50 or 100 mg twice daily. The drug was discontinued in the absence of response at 2 months, disease progression, or unacceptable toxicity. Response was defined as complete response, partial response (PR), hematologic improvement, or reduction in peripheral blood or bone marrow blasts by ≥ 50% (BR). Results The rate of BR for the population in whom efficacy could be assessed (n = 92) was 71% in patients with FLT3-mutant and 42% in patients with FLT3 wild-type. One PR occurred in a patient with FLT3-mutant receiving the 100-mg dose regimen. Both doses were well-tolerated; there were no differences in toxicity or response rate according to the dose of midostaurin. Conclusion These results suggest that midostaurin has hematologic activity in both patients with FLT3-mutant and wild-type. The degree of clinical activity observed supports additional studies that combine midostaurin and other agents such as chemotherapy especially in FLT3-mutant AML.

AMV564 is a novel bispecific bivalent (2x2) immunotherapy that initiates an immunological synapse between T cells and CD33-expressing cells by binding both CD33 and CD3 with strong avidity. CD33 (Siglec-3) is a clinically-validated antigen target that is broadly expressed on the surface of malignant cells in acute myeloid leukemia (AML), myelodysplastic syndromes (MDS), and other hematologic malignancies, as well as on cells that potently suppress immune function, such as myeloid-derived suppressor cells (MDSC). AMV564 has been shown to eliminate MDSCs and restore hematopoiesis, induce potent cytolysis of leukemic cells in patient blood and bone marrow samples, and produce robust antitumor activity in a disseminated model of AML. In vitro studies, including cytotoxicity assays with AML patient samples, human T-cell activation assays, and cytokine-release assays, as well as animal safety studies were performed to characterize the pharmacokinetics, pharmacodynamics, and potential toxicities of AMV564. AMV564 demonstrated potent in vitro antitumor activity with EC50 values of approximately 0.7 - 3 pM. In vitro studies also demonstrated that leukemic cells are more sensitive to T-cell engagement using AMV564 than peripheral blood mononuclear cells by approximately 10-fold. In animal safety studies, AMV564 was tolerated at exposures that exceed those expected to have clinical antitumor activity by > 10-fold. Toxicological findings noted in these studies were anticipated based on the pharmacological activity of AMV564; observed findings included events related to CD3-mediated T-cell activation, cytokine release, and decreases in neutrophil and monocyte counts with rapid recovery. Results from a pharmacokinetic/pharmacodynamic model integrating the preclinical data suggest the potential for a wide therapeutic index for patients with AML. Based on the in vitro and in vivo preclinical data, AMV564 is expected to have a wide therapeutic index, with robust antitumor activity in AML and MDS at doses well below those predicted to be associated with dose-limiting toxicities, and a predictable and monitorable adverse event profile. Citation Format: Tae H. Han, Jeanmarie Guenot, William S. Denney, Eric J. Feldman. The therapeutic potential of AMV564, a novel bispecific bivalent (2x2) T-cell engager, for the treatment of CD33-expressing hematologic malignancies [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 5548.

The farnesyltransferase inhibitor tipifarnib exhibits modest activity against acute myelogenous leukemia. To build on these results, we examined the effect of combining tipifarnib with other agents. Tipifarnib inhibited signaling downstream of the farnesylated small G protein Rheb and synergistically enhanced etoposide-induced antiproliferative effects in lymphohematopoietic cell lines and acute myelogenous leukemia isolates. We subsequently conducted a phase 1 trial of tipifarnib plus etoposide in adults over 70 years of age who were not candidates for conventional therapy. A total of 84 patients (median age, 77 years) received 224 cycles of oral tipifarnib (300-600 mg twice daily for 14 or 21 days) plus oral etoposide (100-200 mg daily on days 1-3 and 8-10). Dose-limiting toxicities occurred with 21-day tipifarnib. Complete remissions were achieved in 16 of 54 (30%) receiving 14-day tipifarnib versus 5 of 30 (17%) receiving 21-day tipifarnib. Complete remissions occurred in 50% of two 14-day tipifarnib cohorts: 3A (tipifarnib 600, etoposide 100) and 8A (tipifarnib 400, etoposide 200). In vivo, tipifarnib plus etoposide decreased ribosomal S6 protein phosphorylation and increased histone H2AX phosphorylation and apoptosis. Tipifarnib plus etoposide is a promising orally bioavailable regimen that warrants further evaluation in elderly adults who are not candidates for conventional induction chemotherapy. These clinical studies are registered at www.clinicaltrials.gov as #NCT00112853.

Reported median overall survival (OS) in patients with mantle cell lymphoma (MCL) has been reported to be just 3-4 years. As a consequence, first-line treatment has become more aggressive. Single-center studies with R-Hyper-CVAD and/or autologous stem-cell transplant (ASCT) have produced 3-year OS rates80%, prompting many to adopt their use. We evaluated outcomes from a single-center cohort managed in a more traditional fashion.We identified patients with MCL evaluated at Weill Cornell Medical Center since 1997, and included those with known date of diagnosis. An online social security database was used to verify survival.We identified 181 patients with MCL, and date of diagnosis could be determined in 111. Three-year OS from diagnosis was 86% [95% confidence interval (CI) 78% to 92%]. Median OS was 7.1 years (95% CI 63-98 months). Adequate information on therapy was available for 75 patients. Only five were treated upfront with (R)-Hyper-CVAD or ASCT while an additional four patients received one of these regimens subsequently. Treatment type had no significant effect on OS.Outcomes with standard approaches can yield similar survival to that achieved with more intensive approaches. Biases may account for the perceived superiority of aggressive strategies.

Purpose: Deforolimus (AP23573), a novel non-prodrug rapamycin analogue, inhibits the mammalian target of rapamycin, a downstream effector of the phosphatidylinositol 3-kinase/Akt and nutrient-sensing pathways. A phase 2 trial was conducted to determine the efficacy and safety of single-agent deforolimus in patients with relapsed or refractory hematologic malignancies. Experimental Design: Eligible patients were assigned to one of five disease-specific, parallel cohorts and given 12.5 mg deforolimus as a 30-minute infusion once daily for 5 days every 2 weeks. A Simon two-stage design was used for each cohort. Safety, pharmacokinetics, pharmacodynamics, and antitumor response were assessed. Results: Fifty-five patients received deforolimus as follows: cohort 1 23 acute myelogenous leukemia, two myelodysplastic syndrome and one chronic myelogenous leukemia in nonlymphoid blast phase; cohort 2, one acute lymphocytic leukemia; cohort 3, nine agnogenic myeloid metaplasia; cohort 4, eight chronic lymphocytic leukemia; cohort 5, nine mantle cell lymphoma and two T-cell leukemia/lymphoma. Most patients were heavily pretreated. Of the 52 evaluable patients, partial responses were noted in five (10%), two of seven agnogenic myeloid metaplasia and three of nine mantle cell lymphoma. Hematologic improvement/stable disease was observed in 21 (40%). Common treatment-related adverse events, which were generally mild and reversible, were mouth sores, fatigue, nausea, and thrombocytopenia. Decreased levels of phosphorylated 4E-BP1 in 9 of 11 acute myelogenous leukemia/myelodysplastic syndrome patients after therapy showed mammalian target of rapamycin inhibition by deforolimus. Conclusions: Deforolimus was well-tolerated in patients with heavily pretreated hematologic malignancies, and antitumor activity was observed. Further investigation of deforolimus alone and in combination with other therapeutic agents is warranted in patients with selected hematologic malignancies.

The CALGB studied the feasibility and effectiveness of adding oblimersen (G3139; Genasense) to imatinib mesylate (IM) in imatinib-resistant chronic phase chronic myeloid leukemia (CML) patients. We hypothesised that IM resistant CML cells are no longer being driven to proliferate by Bcr/Abl activity alone. Instead, the anti-apoptotic protein Bcl-2 would regulate one of the pathways controlling growth and/or viability. Thus, blocking both Bcr/Abl and Bcl-2 simultaneously would result in hematologic and cytogenetic improvement. Oblimersen was administered via continuous intravenous infusion over 10 days every 21 days, along with daily IM. Doses of both drugs were escalated in 3 cohorts; the initial dose of IM was 600 mg/day. Response was defined as a decrease by30% in the percentage of t(9;22) metaphase cells. Twelve patients had primary and nine had secondary imatinib resistance. Ten patients received 4 mg/kg/day oblimersen/600 mg IM, six patients received 7 mg/kg/day oblimersen/600 mg IM and five patients received 7 mg/kg/day oblimersen/800 mg IM. Only two (9.5%) patients achieved a decrease by30% in the percentage of t(9;22) metaphase cells. Although the combination of oblimersen and IM is safe and feasible, we did not observe clinical benefit in these patients with imatinib-resistant CML using these doses and schedule.

Angiogenesis is part of the pathophysiology of myelofibrosis with myeloid metaplasia (MMM). PTK787/ZK 222584 (PTK/ZK) is a novel inhibitor of vascular endothelial growth factor receptors. Twenty-nine patients with MMM received a continuous dosing schedule of PTK/ZK doses of 500 or 750 mg twice daily (BID). Transient potentially PTK/ZK related mild nausea, vomiting, dizziness, fatigue, thrombocytopenia, or anorexia occurred in 15% of patients. Dose limiting toxicities of dyspepsia, proteinurea, and/or mucositis were observed in patients treated with 750 mg BID. One (3%) and five (17%) patients achieved complete remission and clinical improvement, respectively. PTK/ZK has modest activity in patients with MMM.

Purpose Troxacitabine is a non-natural nucleoside analog with unique structural and metabolic features. Bolus intravenous (IV) troxacitabine regimens have shown significant activity in patients with refractory acute myeloid leukemia (AML) and preclinical data suggest that administration via continuous infusion may result in enhanced antitumor activity. Patients and Methods Patients with refractory AML initially received troxacitabine 10.1 mg/m2 by continuous IV infusion (CIVI) for 48 hours. Infusion duration and daily dose were increased in subsequent patient cohorts. Results Forty-eight patients, median age 58 years (range, 21 to 81 years), were treated. Dose-limiting toxicities were mucositis and hand-foot syndrome, and 12.0 mg/m2/d for 5 days was established as the maximum-tolerated dose. Seven patients (15%) achieved complete remission (CR) or CR with incomplete platelet recovery (CRp), with a median survival among responders of 12 months. Steady-state concentrations of troxacitabine were found to be linearly and inversely proportionally related to calculated creatinine clearance at doses of 10.1 and 12.0 mg/m2/d. All patients responding to troxacitabine had steady-state serum drug concentration of more than approximately 80 ng/mL. In 27 patients achieving target troxacitabine plasma concentrations (ie, approximately 80 ng/mL) the CR + CRp rate was 26%. Conclusion Troxacitabine administered as a CIVI allows a significant increase in dose-intensity in comparison to IV bolus regimens, has antileukemic activity, and warrants additional investigation in patients with refractory AML. The recommended phase II study dose is 12.0 mg/m2 daily CIVI for 5 days.

was done in all patients and 5 patients had 1-3 courses of DLI. On follow up of the 43 patients with MC, 24 achieved complete chimerism, 10 had stable mixed chimerism and 9 had rejection (mostly level 3 MC). Two patients developed mild graft versus host disease after DLI. Conclusion: Occurrence of mixed chimerism is common after allogeneic HSCT for thalassaemia after Fludarabine/ Treosulfan/Thiotepa conditioning. Rapid tapering of immunosuppression and judicious use of DLI helps in reducing the risk of secondary graft rejection. Closer monitoring of chimerism after HSCT needs to be done when such conditioning regimens are used. Intermediate-1 6 (20%) Intermediate-2 17 (57%) High 5 (17%) JAK 2 Kinase Positive 11 (37%) Negative 11 (37%) Unknown 8 (24) Spleen Enlarged 18 (60%) Normal 4 (13%) Removed 8 (27%) Albumin 1 Median 3.9 Min 2.6 Max 4.9 LDH 2 Median 487 Min 126 Max 1304 ECOG 0 5 1 17 2 4 Unknown 4

Severe, often refractory anemia is characteristic of the myelodysplastic syndrome associated with chromosome 5q31 deletion. We investigated whether lenalidomide (CC5013) could reduce the transfusion requirement and suppress the abnormal 5q31- clone in patients with this disorder.One hundred forty-eight patients received 10 mg of lenalidomide for 21 days every 4 weeks or daily. Hematologic, bone marrow, and cytogenetic changes were assessed after 24 weeks of treatment by an intention-to-treat analysis.Among the 148 patients, 112 had a reduced need for transfusions (76%; 95% confidence interval [CI], 68 to 82) and 99 patients (67%; 95% CI, 59 to 74) no longer required transfusions, regardless of the karyotype complexity. The response to lenalidomide was rapid (median time to response, 4.6 weeks; range, 1 to 49) and sustained; the median duration of transfusion independence had not been reached after a median of 104 weeks of follow-up. The maximum hemoglobin concentration reached a median of 13.4 g per deciliter (range, 9.2 to 18.6), with a corresponding median rise of 5.4 g per deciliter (range, 1.1 to 11.4), as compared with the baseline nadir value before transfusion. Among 85 patients who could be evaluated, 62 had cytogenetic improvement, and 38 of the 62 had a complete cytogenetic remission. There was complete resolution of cytologic abnormalities in 38 of 106 patients whose serial bone marrow samples could be evaluated. Moderate-to-severe neutropenia (in 55% of patients) and thrombocytopenia (in 44%) were the most common reasons for interrupting treatment or adjusting the dose of lenalidomide.Lenalidomide can reduce transfusion requirements and reverse cytologic and cytogenetic abnormalities in patients who have the myelodysplastic syndrome with the 5q31 deletion. (ClinicalTrials.gov number, NCT00065156 [ClinicalTrials.gov].).

The farnesyltransferase inhibitors (FTIs) are in active clinical development in a variety of human malignancies. The most promising activity to date has been demonstrated in patients with hematologic malignancies, in particular acute myeloid leukemia (AML) and myelodysplastic syndrome (MDS). In patients with MDS, two nonpeptidomimetic agents, tipifarnib (Zarnestra, Johnson & Johnson, New Brunswick, NJ) and lonafarnib (Sarasar, Schering-Plough, Kenilworth, NJ) have been the most extensively studied. In both phase I and phase II trials, tipifarnib has demonstrated significant efficacy, with overall response rates of 30% and complete remissions in about 15%. Dose-limiting adverse effects have been primarily myelosuppression, although fatigue, neurotoxicity, and occasional renal dysfunction have required dose reductions. Lonafarnib in patients with MDS has also resulted in clinical responses in approximately 30%, including significant improvements in platelet counts. Lonafarnib has been associated primarily with diarrhea and other gastrointestinal toxicity, anorexia, and nausea, which has limited its efficacy. Clinical response correlation with documentation of inhibition of farnesyltransferase and/or evidence of decreased farnesylation of downstream protein targets has not been demonstrated with either agent. In addition, the presence of an activating Ras mutation has not predicted response to therapy with FTIs in MDS and AML. Despite this lack of evidence, significant clinical efficacy of the FTIs has been observed in MDS, on a par with the efficacy of currently available chemotherapeutic agents, leading to further development of this new class of drugs in MDS and AML.

Effective treatment options for adults with therapy-related AML continues to be an area of unmet need. Genetic and molecular changes within these leukemias confer resistance to standard chemotherapy regimens. Emerging developmental therapeutics in this area has focused on several approaches. These include; novel delivery of chemotherapy as well as newer DNA-damaging agents delivered through antibody-drug conjugates, increased use of hypomethylating agents, and molecularly-directed small molecules against specific mutations commonly occurring in secondary AML. Results of this efforts are encouraging, but to date, no clear improvements have been demonstrated in this most difficult to treat population.

Purpose Lintuzumab (HuM195) is an unconjugated humanized murine monoclonal antibody directed against the cell surface myelomonocytic differentiation antigen CD33. In this study, the efficacy of lintuzumab in combination with induction chemotherapy was compared with chemotherapy alone in adults with first relapsed or primary refractory acute myeloid leukemia (AML). Patients and Methods Patients with relapsed or primary resistant AML (duration of first response, zero to 12 months) were randomly assigned to receive either mitoxantrone 8 mg/m2, etoposide 80 mg/m2, and cytarabine 1 g/m2 daily for 6 days (MEC) in combination with lintuzumab 12 mg/m2, or MEC alone. Overall response, defined as the rate of complete remission (CR) and CR with incomplete platelet recovery (CRp), was the primary end point of the study, with additional analyses of survival time and toxicity. Results A total of 191 patients were randomly assigned from November 1999 to April 2001. The percent CR plus CRp with MEC plus lintuzumab was 36% v 28% in patients treated with MEC alone (P = .28). The overall median survival was 156 days and was not different in the two arms of the study. Apart from mild antibody infusion–related toxicities (fever, chills, and hypotension), no differences in chemotherapy-related adverse effects, including hepatic and cardiac dysfunction, were observed with the addition of lintuzumab to induction chemotherapy. Conclusion The addition of lintuzumab to salvage induction chemotherapy was safe, but did not result in a statistically significant improvement in response rate or survival in patients with refractory/relapsed AML.

This meeting was convened by Richard T. Silver, M.D. and co-chaired by Jerry L. Spivak, M.D. It was held from 16 to 18 October 2003 in New York City, New York, USA. Thirty-nine invited speakers from nine different countries participated in the conference. There were more than 350 attendees. There were formal presentations and discussions on biology, clinical aspects, and management of patients with these diverse bone marrow stem cell disorders linked by a variable progression to acute myeloid leukemia. Of considerable interest, a clinical symposium exclusively for patients was held the day preceding the meeting at which John Bennett, Tiziano Barbui, Richard Silver, Jerry Spivak, and Ayalew Tefferi spoke on various topics pertaining to these diseases. This proved to be highly informative to the patients who reported that they enjoyed the program immensely. This was sponsored by the Cancer Research & Treatment Fund, Inc. Representatives of the Myelodysplasia Foundation were also present. This meeting report provides a summary of five different sections prepared by one or more of the session chairs. The keynote address was given by Shahin Rafii (Cornell Medical Center). Most appropriately, this talk focused on the expression and activation of angiogenic factors which play a crucial role in the progression of both myeloproliferative disorders and myelodysplastic syndromes (MDS). Among the known factors, vascular endothelial growth tyrosine kinase receptors (VEGF-R1, R2, and R3) support proliferation, survival, and mobility. Rafii's team has demonstrated that these receptors are expressed on subsets of primary hematopoietic cells as well as leukemic cells. Some leukemic cells express both VEGF-A and VEGF-R2, resulting in the generation of an autocrine loop that supports survival and within the osteoblastic zone translocating these cells to the vascular enriched niche for receipt of molecular instructions required for proliferation and differentiation. A pathologic correlation can be seen in some patients with the identification of abnormal localization of immature precursors (ALIP) in the central portions of the medullary cavity. Misplaced megakaryocytes can release pro-fibrotic factors, including platelet derived growth factors and transforming growth factor-beta. Collectively, these data suggest that chronic disregulation of angiogenic factors alter the microenvironment dislocating marrow stem cells that force both proliferation and differentiation in varying degrees, contributing to these hematological disorders.

Purpose: We conducted a single-center, dose-escalation study evaluating the safety, pharmacokinetics, and efficacy of epratuzumab, an anti-CD22 humanized monoclonal antibody, in patients with aggressive non-Hodgkin’s lymphoma.Experimental Design: Epratuzumab was administered once weekly for 4 weeks at 120-1000-mg/m2 doses to 56 patients [most (n = 35) with diffuse large B-cell lymphoma].Results: Patients were heavily pretreated (median, 4 prior therapies), 25% received prior high-dose chemotherapy with stem cell transplant, and 84% had bulky disease (≥5 cm). Epratuzumab was well tolerated, with no dose-limiting toxicity. Most (95%) infusions were completed within 1 h. The mean serum half-life was 23.9 days. Across all dose levels and histologies, objective responses (ORs) were observed in five patients (10%; 95% confidence interval, 3–21%), including three complete responses. In patients with diffuse large B-cell lymphoma, 15% had ORs. Overall, 11 (20%) patients experienced some tumor mass reduction. Median duration of OR was 26.3 weeks, and median time to progression for responders was 35 weeks. Two responses are ongoing at ≥34 months, including one rituximab-refractory patient.Conclusions: These data demonstrate that epratuzumab has a good safety profile and exerts antitumor activity in aggressive non-Hodgkin’s lymphoma at doses of ≥240 mg/m2, thus warranting further evaluation in this clinical setting.

Objective. To describe clinical and laboratory features of a cohort of patients with chronic myelogenous leukemia (CML) who developed Ph − , trisomy 8 + metaphases while on treatment with imatinib mesylate. Patients and Methods. Conventional cytogenetics and triple-color interphase fluorescence in situ hybridization were used to identify 5 of 310 studied patients who, on follow-up analysis, had Ph − , trisomy 8 + cells while on therapy. Results. None of the 5 patients had cytogenetic evidence of clonal evolution at the start of treatment with imatinib. All patients developed grade 3 or 4 neutropenia and thrombocytopenia during treatment. The emergence of Ph − , trisomy 8 + metaphases was seen at 3, 6, 13, 16, and 18 months from the start of treatment and was present at multiple time points. The maximum number of trisomy 8 metaphases ranged from 25 to 50%. Concomitantly, all patients had a profound suppression of Ph + cells (ranging from 0 to 65%) as well as the appearance of normal metaphases, ranging from 6 to 55%. None of the patients has shown clinical or hematologic signs of progression to a more advanced phase of CML. Conclusions. While on treatment with imatinib mesylate a small group (less than 5%) of patients with CML developed Ph − trisomy 8 + clone associated with pancytopenia. None of the patients developed clinical or hematological signs of progression to a more advanced phase of CML. These observations suggest that identification of trisomy 8 cells may represent clonal Ph − cells that were uncovered by treatment with a selective and potent inhibitor of Ph + cells.

HuM195 is a humanized, unconjugated, anti-CD33 monoclonal antibody. Fifty adult patients with relapsed or refractory AML were randomized to receive HuM195 at a dose of 12 or 36 mg/m(2) by intravenous infusion over 4 h on days 1-4 and 15-18. Patients with stable or responding disease received two additional cycles on days 29-32 and 43-46. HuM195 was given as first salvage therapy in 24 patients and as second or subsequent salvage therapy in 26 patients. Pretreatment blast percentage in the marrow was between 5 and 30% in 20 patients with the others having blast counts greater than 30%. The median age of patients was 62 years (range 26-86) and CD33 was detected in 95% of patients for whom immunophenotyping was available. Of 49 evaluable patients, two complete and one partial remission were observed. All three responses were in patients treated at the 12 mg/m(2) dose level and all had baseline blast percentages less than 30%. Decreases in blast counts ranging from 30 to 74% were seen in nine additional patients. Infusion-related events of fever and chills occurred in the majority of patients and were generally mild and primarily related to the first dose of antibody. No hepatic, renal or cardiac toxicities were observed and other adverse events such as nausea, vomiting, mucositis and diarrhea were uncommon or felt to be unrelated to HuM195. In addition, anti-HuM195 responses were not detected. HuM195 as a single agent has minimal, but observable, anti-leukemic activity in patients with relapsed or refractory AML and activity is confined to patients with low burden disease. No significant differences in clinical efficacy or toxicity were seen between the two dose levels of antibody. HuM195 was well tolerated with infusion-related fevers and chills the predominant toxicities seen. Meaningful clinical efficacy of this unconjugated monoclonal antibody may be realized only in patients with minimal residual disease, or in combination with chemotherapy.

Blast crisis is the most advanced stage of chronic myelogenous leukemia (CML) and is highly refractory to therapy. CML is caused by expression of the chimeric BCR-ABL tyrosine kinase oncogene, the product of the t(9;22) Philadelphia translocation. Imatinib (Glivec, formerly STI571) is a rationally developed, orally administered inhibitor of the Bcr-Abl tyrosine kinase. A total of 260 patients with CML were enrolled in a phase II trial, of whom 229 had a confirmed diagnosis of CML in blast crisis. Patients were treated with imatinib in daily oral doses of 400 mg or 600 mg. Imatinib induced hematologic responses in 52% of patients and sustained hematologic responses lasting at least 4 weeks in 31% of patients, including complete hematologic responses in 8%. For patients with a sustained response, the estimated median response duration was 10 months. Imatinib induced major cytogenetic responses in 16% of patients, with 7% of the responses being complete. Median survival time was 6.9 months. Nonhematologic adverse reactions were frequent but generally mild or moderate. Episodes of severe cytopenia were also frequent and were attributable to the underlying condition and treatment with imatinib. Drug-related adverse events led to discontinuation of therapy in 5% of patients, most often because of cytopenia, skin disorders, or gastrointestinal reactions. These results demonstrate that imatinib has substantial activity and a favorable safety profile when used as a single agent in patients with CML in blast crisis. Additional clinical studies are warranted to explore the efficacy and feasibility of imatinib used in combination with other antileukemic drugs.

The objective of this work was to determine the safety and efficacy of gemtuzumab ozogamicin in patients with poor prognosis acute myeloid leukemia (AML). Patients with the following diagnoses/characteristics were treated with 1-3 infusions of gemtuzumab ozogamicin at a dose of 9 mg/m2: (1) relapse of AMLor = 6 months of first complete remission (CR); (2) AML refractory to chemotherapy at initial induction or at first relapse; (3) AML in second or greater relapse; (4) myeloid blast crisis of chronic myeloid leukemia (CML); (5) untreated patientsor = 70 years oror = 55 years with abnormal cytogenetics (excluding inv 16, t(15;17) and t(8;21)) and/or an antecedent hematologic disorder; (6) refractory anemia with excess blasts in transformation (RAEBT). Forty-three patients, ages 19-84 (mean 62), were treated, including 7 patients with untreated AML age70 years, 2 with untreated RAEBT, 14 with AML first salvage (first remission 0-6 months), 15 with AMLor = second salvage and 14 with myeloid blast phase of CML. The overall response rate was 14%, with 4/43 (9%) patients achieving CR and 2/43 (5%) achieving CR without platelet recovery. The most significant toxicity was neutropenic fever, which occurred in 84% of patients. In conclusion, in patients with relapsed/refractory AML, gemtuzumab ozogamicin has a comparable response rate to single-agent chemotherapy and may offer a more favorable toxicity profile.