Search

Background: Adaptive resistance mechanisms leading to treatment failure have been identified in older patients receiving venetoclax (VEN) in combination with either azacitidine or low dose cytarabine (LDAC) as frontline therapy for acute myeloid leukemia (AML). These include the expansion or secondary emergence of kinase activating mutations, including FLT3-ITD in patients with non-adverse karyotype (NON-ADV), as well as TP53 mutations among patients with adverse karyotype (ADV)(DiNardo & Tiong et al, Blood 2020). INTERVENE is a phase 2 study evaluating the safety and efficacy of the "risk-stratified" addition of a novel third agent to VEN-LDAC, delivered in tandem to LDAC to minimize the risk of myelotoxicity (Figure 1A). To mitigate VEN resistance associated with activated kinases in NON-ADV risk AML, midostaurin (MIDO), a FLT3/multi-kinase inhibitor, was incorporated in combination with VEN. To address VEN resistance associated with TP53 defects in ADV risk AML, a HDAC inhibitor pracinostat (PRAN) was incorporated in accordance with pre-clinical studies suggesting synergistic induction of TP53 independent cell death with VEN plus HDAC inhibition (Salmon et al, ASH 2018). We hereby report the results of the dose-finding safety run-in phase of the study. Methods: Eligibility: Patients with treatment naïve AML (excluding APL), aged ≥60 years and unfit for intensive chemotherapy were included. Prior hypomethylating agents for antecedent myeloid neoplasms were permitted with a 14-day washout. Patients were stratified according to cytogenetic risk, as per Medical Research Council 2010 criteria. Treatment: VEN D1-28 (with dose ramp-up in cycle 1) was combined with LDAC (20mg/m 2 SC D1-10), with the third agent starting after/on the last day of LDAC (Fig 1A). Each cycle was 28 days. In the NON-ADV stratum (VEN-LDAC-MIDO), 2 dose levels were explored: (L1) VEN 400mg + LDAC + MIDO 50mg BD D11-28; (L2) VEN 600mg + LDAC + MIDO 50mg. In the ADV stratum (VEN-LDAC-PRAN), 3 dose levels were tested: (L1) VEN 400mg + LDAC + PRAN 45mg starting D10 and given 3x/week orally for a total of 9 doses; (L2) VEN 600mg + LDAC + PRAN 45mg; (L3) VEN 600mg + LDAC + PRAN 60mg. Azole antifungals were prohibited in cycle 1 but allowed from cycle 2 with VEN dose modification. Endpoints (safety run-in): Primary: occurrence of dose-limiting toxicities (DLT) during cycle 1 and determination of recommended phase 2 doses (RP2D) using a Bayesian Logistic Regression Model. Secondary: Preliminary response rates. Molecular studies: Next generation sequencing using a custom 48-gene Roche KAPA HyperCapture myeloid panel and FLT3-ITD targeted amplicon sequencing were performed on baseline bone marrow samples. First patient enrolled: 7SEP2020. Data cut-off: 29JUN2021. Results: 32 patients were enrolled: 18 in NON-ADV and 14 in ADV strata, respectively. Two patients in the NON-ADV stratum withdrew within the first 7 days due to non-therapy related reasons (1=personal, 1=incidental lung lesion) and were not DLT/response evaluable. Median age was 77 years (68-87; 69% ≥75 years). 43.8% (14/32) had secondary/therapy related AML. Although gastrointestinal adverse events (AE) during cycle 1 were more common in VEN-LDAC-PRAN arm with nausea (57 vs 17%), vomiting (36% vs 6%) and diarrhea (50% vs 22%), grade 3+ toxicities were uncommon (0-7%)(Table 2). Occurrence of febrile neutropenia was similar between the two arms. 30-day mortality was 0% and 14% (2/14: 1=infection, 1=disease progression) for NON-ADV and ADV strata, respectively. No DLTs were observed in either stratum across all dose levels, thus the RP2D was the highest dose level explored for both triplet combinations. The intention-to-treat overall response rate CR+CRi+CRh was 72.2% (13/18) in the NON-ADV arm and 57.1% (8/14) in ADV arm. The expanded response rate including PR and MLFS was 77.8% (14/18) and 71.4% (10/14) in the NON-ADV and ADV strata, respectively. Median time to best response was 1 cycle (range 1-6). Updated response and survival outcomes will be presented at the meeting. Conclusion: The addition of MIDO or PRAN to VEN-LDAC was tolerable in older/unfit patients with treatment naïve AML. Preliminary efficacy with this risk-stratified approach compared favorably to prior studies with VEN-LDAC alone (Wei et al Blood 2020: CR+CRi 56% in NON-ADV, 28% in ADV). The randomized phase 2 part of this tandem triplet strategy with the goal of preventing adaptive resistance is underway. Figure 1 Figure 1. Disclosures Chua: Abbvie: Other: Conference travel and accommodation . Reynolds: Alcon: Current equity holder in publicly-traded company; Abbvie: Research Funding; Novartis AG: Current equity holder in publicly-traded company. Enjeti: Astra Zeneca: Honoraria; Sanofi: Honoraria; AbbVie: Honoraria; Roche: Speakers Bureau; Novartis: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau. Hiwase: AbbVie: Membership on an entity's Board of Directors or advisory committees; Novartis: Membership on an entity's Board of Directors or advisory committees. Marlton: Janssen: Honoraria, Membership on an entity's Board of Directors or advisory committees; AstraZeneca: Honoraria, Membership on an entity's Board of Directors or advisory committees; Gilead: Honoraria, Membership on an entity's Board of Directors or advisory committees; F. Hoffmann-La Roche Ltd: Membership on an entity's Board of Directors or advisory committees; Novartis: 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; Astellas: Honoraria, Membership on an entity's Board of Directors or advisory committees; Queensland Health: Current Employment; BeiGene: Honoraria, Membership on an entity's Board of Directors or advisory committees; Jazz: Honoraria, Membership on an entity's Board of Directors or advisory committees. Bajel: Abbvie, Amgen, Novartis, Pfizer: Honoraria; Amgen: Speakers Bureau. Grove: Astellas: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees; Abbvie: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees. Cooney: Amgen: Other: Travel, accommodation, expenses ; Roche: Other: Travel, accommodation, expenses ; Novartis: Other: Online conference registration . Beligaswatte: Astellas: Membership on an entity's Board of Directors or advisory committees. Anstee: Walter and Eliza Hall Institute: Patents & Royalties: Dr Anstee was a former employee of the Walter and Eliza Hall Institute and is eligible for a fraction of the royalty stream related to Venetoclax. Perera: Abbvie: Speakers Bureau; BMS: Speakers Bureau. Ritchie: Takeda: Research Funding; BMS: Research Funding; Novartis: Honoraria; CRISPR Therapeutics: Research Funding; Amgen Inc: Honoraria, Research Funding; CSL: Honoraria. Wei: Genentech: Membership on an entity's Board of Directors or advisory committees; Agios: Membership on an entity's Board of Directors or advisory committees; Celgene/BMS: Membership on an entity's Board of Directors or advisory committees, Research Funding, Speakers Bureau; Janssen: Membership on an entity's Board of Directors or advisory committees; Macrogenics: Membership on an entity's Board of Directors or advisory committees; Roche: Membership on an entity's Board of Directors or advisory committees; Servier: 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; Gilead: Membership on an entity's Board of Directors or advisory committees; Astra Zeneca: Membership on an entity's Board of Directors or advisory committees, Research Funding; Pfizer: Membership on an entity's Board of Directors or advisory committees; Amgen: 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, Speakers Bureau; Abbvie: Membership on an entity's Board of Directors or advisory committees, Research Funding, Speakers Bureau. OffLabel Disclosure: This presentation will focus on the ALLG INTERVENE clinical trial combining venetoclax+LDAC+midostaurin or venetoclax+LDAC+pracinostat. Although venetoclax and midostaurin are individually FDA-approved in some indications, the combinations examined in this clinical trial have not been approved by FDA.

A tale of two siblings: two cases of AML arising from a single pre-leukemic DNMT3A mutant clone

Acute promyelocytic leukemia (APML) is characterized by the PML-RARA fusion gene. Formerly associated with extremely high rates of early death, APML has been transformed into a curable disease by t...

Thymoglobulin (TG) given with conditioning for allogeneic haematopoietic SCT (alloHSCT) is effective in reducing the risk of acute and chronic GVHD (cGVHD). Whether conventional risk factors for GVHD apply to TG-conditioned alloHSCT is unknown. We retrospectively studied 356 adults from three centres who received TG 4.5 mg/kg prior to alloHSCT for haematologic malignancy. Donors were unrelated in 64%. At 3 years, OS was 61% (95% confidence interval (CI) 55-67%), cumulative incidence of relapse was 28% (95% CI 23-33%) and non-relapse mortality was 19% (14-24%). The cumulative incidences of grade 2-4, and grade 3-4 acute GVHD were 23% (95% CI 19-28%) and 10% (95% CI 6-13%), respectively. The cumulative incidence of cGVHD requiring systemic immunosuppression (cGVHD-IS) at 3 years was 32% (95% CI 27-37%). On multivariate analysis, counterintuitively, recipient age over 40 was associated with a significantly decreased risk of cGVHD-IS (P=0.001). We report for the first time a paradoxical association of older age with reduced cGVHD in TG recipients, and conclude that traditional risk factors for GVHD may behave differently in the context of pre-transplant TG.

The proportion of patients with acute myeloid leukemia (AML) cured is increased by administering high-dose cytarabine (HiDAC). It remains uncertain whether to administer HiDAC as induction or consolidation, and whether ≥1 cycle of HiDAC is required. Our retrospective study of 416 adult AML patients, excluding good risk cytogenetics, compared a single cycle of HiDAC-based therapy followed by 2 cycles of standard-dose cytarabine (SDAC) (HiDAC induction cohort) with SDAC-based chemotherapy followed by 2 cycles of HiDAC-based chemotherapy (HiDAC consolidation cohort). Complete remission (CR) rate was greater in the HiDAC induction cohort (90% vs 78%, P

Abstract 2285 Background: HLA allo-immunized patients often receive matched platelets only after demonstrating platelet transfusion refractoriness (PTR). If further risk stratification was possible, high risk patients could be considered for pre-emptive HLA-matched platelets, cryopreserved autologous platelets, or possibly thrombopoietin analogues. Micro-bead flow cytometry is widely used to detect anti-HLA antibodies, and mean fluorescence intensities (MFI) obtained from these assays correlate with antibody titers. We asked whether MFIs could be used to stratify the risk of PTR among allo-immunized patients. Study design: We retrospectively identified 387 patients who received an autologous stem cell transplant or induction therapy for acute leukemia, between January 2005 and March 2012. All patients had a serum sample taken for HLA antibody assay within 6 weeks of commencing cellular blood product transfusions. No patient was scheduled to receive prophylactic HLA matched platelets. The primary endpoint was the development of PTR. To minimize the influence of sensitization occurring after screening, only outcomes during the first 2 weeks from commencing cellular blood product transfusions were considered. PTR was defined as having received ≥ 2 consecutive RDPLT transfusions associated with an 18–24h corrected count increment of < 2.5 at 18 – 24 hours. Antibody testing was performed using a micro-bead flow cytometry assay (Lifecodes LifeScreen Deluxe, with positive results confirmed by Lifecodes Class I ID assay, Gen-Probe Transplant Diagnostics, Stamford, CT) either during the treatment period, or on serum samples stored at −30°C. Mean fluorescence intensities (MFI) were acquired using a Luminex 100 analyzer (Luminex Corporation, Austin, TX), and analyzed using Lifecodes Quicktype v2.5.5 (Gen-Probe Transplant Diagnostics, Stamford, CT). We defined the predictor variable avgMFI to be the average MFI of the 7 individual beads in the assay, weighted by whether the presence of antibodies was confirmed or not: where w = 1 if the presence of antibodies is confirmed, and 0 otherwise; and subscript i refers to the ith class I bead. Results: Antibodies were detected in 57 (14.7%) patients of whom 45 (78.9%) were female. A total of 1443 random donor platelet (RDPLT) transfusions (mean platelet count 2.4×1011/unit) were studied. Sixty six (17%) patients developed PTR, of whom 28 had detectable antibodies; 29 of 321 patients who did not develop PTR also tested positive. Among antibody positive patients, median avgMFI for refractory patients was 4589 versus 349 for patients who were not, Wilcoxon rank sum test P< 0.0001. (Figure 1). The area under the receiver operating characteristic curve for avgMFI as a predictor of PTR was 0.8633 (95% confidence interval: 0.7664 – 0.9602). Higher avgMFIs also correlated with a broader range of target antigens, likely due to increasingly avid binding to cross-reactive epitopes. (Spearman's r = 0.7736 for correlation between avgMFI and panel reactive antibody percentages (cPRA), calculated in reference to the general American population, and used here as a surrogate for the range of antibody specificities). cPRA was >80% in 25/27 patients with avgMFI>1000, suggesting poor ability to discriminate among patients with moderate to high antibody titers, and was not an independent predictor of PTR. Hence, while the increased probability of encountering a cognate antigen on a RDPLT may partly explain the correlation between avgMFI and PTR, the avidity of binding, represented in vitro by the MFIs, appears to be a more significant determinant of risk. In conclusion, we provide evidence for the concept that PTR risk due to HLA allo-immunization is usefully predicted by the MFIs of antibodies detected using micro-bead flow cytometry. Our model allows cut-offs for identifying high risk patients to be based on the degree of risk acceptable in a given clinical situation. This should enable hematology units to develop risk-adapted strategies for supporting allo-immunized thrombocytopenic patients. Disclosures: No relevant conflicts of interest to declare.

Introduction: The optimal treatment approach for newly diagnosed patients with AML remains uncertain. HiDAC is widely considered to increase the proportion of patients cured compared to standard-dose cytarabine. However, it remains uncertain whether HiDAC is best given during induction or consolidation, and how many cycles of HiDAC are optimal. Many centres in Australia treat younger patients (age ≤60 yrs) with newly diagnosed AML with one of two approaches: either 7+3 induction followed by HiDAC-2 consolidation for 2 cycles; or a single course of HiDAC-3±7 induction followed by 2 cycles of lower dose cytarabine-based therapy (eg 5+2±5). Our retrospective study compared the outcomes of these 2 approaches in a large cohort of Australian patients treated at 5 centres. Methods: Consecutive patients aged ≤60 yrs with a new diagnosis of AML (de novo or secondary) were included in the study if they were planned for treatment with either: 1) cytarabine 100 mg/m2 for 7 days plus idarubicin 12 mg/m2 for 3 days (7+3) induction followed by 2 cycles of HiDAC 3 g/m2 days 1,3,5,7 plus idarubicin 12 mg/m2 for 2 days (HiDAC consolidation cohort); or 2) HiDAC 3 g/m2 days 1,3,5,7 plus idarubicin 9-12 mg/m2 for 3 days ± etoposide 75-100 mg/m2 for 7 days as induction followed mostly by cytarabine 100 mg/m2 for 5 days plus idarubicin 9-12 mg/m2 for 2 days ± etoposide 75-100 mg/m2 for 5 days as consolidation (HiDAC induction cohort). Patients were diagnosed from 1999 to June 2013, and were followed for at least 12 months with data cut off June 2014. Results: 486 patients were included: HiDAC consolidation cohort n=251; HiDAC induction cohort n=235. The HiDAC consolidation cohort had a greater median age (49 vs 47 yrs, p=0.02) and more patients with good risk cytogenetics (16% vs 8%, p= Conclusions: OS and PFS using HiDAC as induction or consolidation therapy were similar, and compared favourably to published data. Interestingly, the better CR rate and a greater use of alloHSCT in CR1 in the HiDAC induction cohort did not lead to a better PFS or OS - because of a greater relapse rate in this cohort - primarily seen in those patients not undergoing alloHSCT in CR1. In the absence of mutational prognostic information, these data may suggest that HiDAC as induction therapy can achieve CR in patients with biologically higher risk disease who have a higher relapse rate, and that including 2 cycles of HiDAC in consolidation in the absence of alloHSCT in CR1 is a more effective therapy than a single cycle of HiDAC administered during induction therapy. Disclosures Mollee: Celgene: Membership on an entity's Board of Directors or advisory committees, Research Funding; Janssen: Membership on an entity's Board of Directors or advisory committees, Research Funding; Amgen: Membership on an entity's Board of Directors or advisory committees; Bristol-Myers Squibb: Membership on an entity's Board of Directors or advisory committees; Nilelse: Research Funding.