ALBERT

Description: BACKGROUND: The median age for diagnosis of acute myeloid leukemia (AML) is 68 years. Elderly patients are often ineligible for intensive chemotherapy and have limited treatment options. Venetoclax (Ven), an oral agent that targets the antiapoptotic protein, BCL-2, has demonstrated high rates of remission (〉60%) when administered in combination with low-dose cytarabine (LDAC), and could represent a potent therapeutic option for patients ineligible for intensive chemotherapy. METHODS: This open-label, phase 1/2 study (NCT02287233) evaluated the safety and efficacy of venetoclax in combination with LDAC in patients with previously untreated AML who were ineligible for intensive chemotherapy due to comorbidities or age. Patients had an Eastern Cooperative Oncology Group (ECOG) performance score of 0-2, had adequate hepatic and renal function, and were enrolled from December 2014 to May 2017. In the dose escalation portion of the study, 600 mg venetoclax was determined to be the recommended phase 2 dose (RPTD). Venetoclax was initiated at 50 or 100 mg daily and dose escalated over 4-5 days to reach the RPTD. In subsequent 28 day cycles, venetoclax was administered at 600 mg on all days. LDAC (20 mg/m2 daily) was subcutaneously administered on days 1-10 of each cycle. At the beginning of the study, concominant strong and moderate CYP3A inhibitor use was prohibited; however, as additional safety and pharmacokinetic data became available, their use was allowed with appropriate venetoclax dose adjustments. Time to first response, rates of complete remission (CR), CR with incomplete blood count recovery (CRi), CR with partial hematologic recovery (CRh), duration of response, achievement of transfusion independence, overall survival (OS) and adverse events (AEs) were evaluated. Minimal residual disease (MRD) was evaluated centrally by multicolor flow cytometry at a cutoff of 10-3 leukemic cells. RESULTS: Data cutoff was November 8, 2017. Of 82 patients treated with 600 mg of venetoclax, 65% were male, 95% white race, 60% had intermediate and 32% had poor cytogenetic risk, and 49% had secondary AML (of whom 60% had prior HMA exposure). Transfusion dependence for red blood cells (RBC) and platelets within 8 weeks prior to venetoclax treatment was 65% (53/82) and 28% (23/82) of patients, respectively. Most common grade ≥3 AEs across all patients were febrile neutropenia (43%), thrombocytopenia (38%), neutropenia (27%), and anemia (27%). Laboratory evidence of grade 3 tumor-lysis syndrome (TLS) was observed in two patients; both patients achieved the target dose of venetoclax. Forty seven percent of patients received moderate (40%) or strong (7%) CYP3A inhibitors for at least 7 days (predominantly azole antifungals); no relevant differences in serious adverse event rates were observed. Key efficacy results are shown in the Table. Median time to first response was 1.4 months, and 54% and 46% of patients achieved CR/CRi and CR/CRh, respectively. The rates of CR/CRi for patients with secondary and de novo AML were 35% and 71%, respectively; median DOR for those with secondary and de novo AML was 8.1 and 11.6 months, respectively. Patients with selected genetic mutations achieved the following rates of CR/CRi: TP53, 30%; IDH1/2, 72%; FLT3, 44%; NPM1, 89%. MRD response below 10-3 cutoff was achieved by 32% of patients with CR/CRi; median OS has not yet been reached for these patients. Among patients that were RBC or platelet transfusion dependent at baseline, 49% (26/53) and 65% (15/23), respectively, achieved transfusion independence while on venetoclax therapy. CONCLUSIONS: Venetoclax in combination with LDAC led to rapid, deep, and durable responses in patients with AML who were ineligible for intensive chemotherapy. Venetoclax plus LDAC demonstrated an improved CR rate (26% vs. 8%), CR/CRi rate (54% vs. 11%) and median overall survival (10 months vs. 5 months) compared to the historical rates with LDAC alone. Furthermore, a majority of patients achieved transfusion independence during venetoclax therapy. Strong and moderate CYP3A inhibitors, including azole antifungals, were safely coadministered with appropriate venetoclax dose adjustments. These results demonstrate that venetoclax, in combination with LDAC, represents an effective therapeutic option for patients with AML who are not suitable for standard induction therapy. Disclosures Wei: Novartis: Consultancy, Honoraria; Amgen: Consultancy, Honoraria; Celgene: Consultancy, Honoraria, Research Funding; Servier: Consultancy, Honoraria, Research Funding; AbbVie: Consultancy, Honoraria, Research Funding. Strickland:Boehringer Ingelheim: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding; Novartis: Consultancy, Membership on an entity's Board of Directors or advisory committees; Pfizer: Consultancy, Membership on an entity's Board of Directors or advisory committees; Astellas Pharma: Consultancy; Baxalta: Consultancy, Membership on an entity's Board of Directors or advisory committees; CTI Biopharma: Consultancy, Membership on an entity's Board of Directors or advisory committees; Tolero Pharmaceuticals: Consultancy, Membership on an entity's Board of Directors or advisory committees; Sunesis Pharmaceuticals: Consultancy, Research Funding. Fiedler:Amgen: Consultancy, Other: Meeting attendance, Patents & Royalties, Research Funding; ARIAD/Incyte: Consultancy; Novartis: Consultancy; Pfizer: Consultancy, Research Funding; Gilead: Other: Meeting attendance; GSO: Other: Meeting attendance; Teva: Other: Meeting attendance; JAZZ pharma: Other: Meeting attendance; Daiichi Sankyo: Other: Meeting attendance. Lin:Jazz Pharmaceuticals: Honoraria. Walter:Actinium Pharmaceuticals, Inc: Other: Clinical Trial support , Research Funding; Amgen Inc: Other: Clinical Trial Support, Research Funding; Amphivena Therapeutics, Inc: Consultancy, Other: Clinical Trial Support, Research Funding; Aptevo Therapeutics, Inc: Consultancy, Other: Clinical Trial Support, Research Funding; Covagen AG: Consultancy, Other: Clinical Trial Support, Research Funding; Seattle Genetics, Inc: Consultancy, Other: Clinical Trial Support, Research Funding; Pfizer, Inc: Consultancy; Boehringer Ingelheim Pharma GmbH & Co. KG: Consultancy. Hong:Genentech Inc/Roche: Employment, Other: Ownership interests PLC. Chyla:AbbVie, Inc: Employment, Equity Ownership. Popovic:AbbVie Inc: Employment, Equity Ownership. Fakouhi:AbbVie, Inc: Employment, Equity Ownership. Xu:AbbVie, Inc: Employment, Equity Ownership. Hayslip:AbbVie: Employment, Equity Ownership. Roboz:Bayer: Consultancy; Pfizer: Consultancy; Bayer: Consultancy; AbbVie: Consultancy; AbbVie: Consultancy; Orsenix: Consultancy; Cellectis: Research Funding; Aphivena Therapeutics: Consultancy; Otsuka: Consultancy; Roche/Genentech: Consultancy; Astex Pharmaceuticals: Consultancy; Orsenix: Consultancy; Roche/Genentech: Consultancy; Daiichi Sankyo: Consultancy; Jazz Pharmaceuticals: Consultancy; Eisai: Consultancy; Celgene Corporation: Consultancy; Sandoz: Consultancy; Novartis: Consultancy; Celgene Corporation: Consultancy; Cellectis: Research Funding; Argenx: Consultancy; Jazz Pharmaceuticals: Consultancy; Daiichi Sankyo: Consultancy; Sandoz: Consultancy; Janssen Pharmaceuticals: Consultancy; Astex Pharmaceuticals: Consultancy; Janssen Pharmaceuticals: Consultancy; Celltrion: Consultancy; Aphivena Therapeutics: Consultancy; Argenx: Consultancy; Celltrion: Consultancy; Pfizer: Consultancy; Novartis: Consultancy; Otsuka: Consultancy; Eisai: Consultancy.

Description: Background: Multiple studies have demonstrated the modest efficacy of low-dose cytarabine (LDAC) in older patients (≥65 years) with Acute Myeloid Leukemia(AML) who are unlikely to benefit from an anthracycline and cytarabine intensive induction [CR/CRi rates of 10 - 26%; (CRi = complete remission with incomplete marrow recovery)]. Venetoclax, a selective BCL-2 inhibitor has demonstrated single-agent activity in patients with relapsed and refractory AML [Konopleva et al., ASH 2014]. When administered with LDAC, the recommended phase 2 dose (RP2D) of venetoclax was 600 mg daily [Lin et al., ASCO 2016 (abstract 7007)]. Here we present the safety and efficacy data at RP2D of venetoclax from the dose escalation and expansion phases of the study (NCT02287233). Methods: Patients enrolled as of 15DEC2015 are included in this analysis with a data cut-off date of 31MAR2016. Patients were eligible if considered unfit for intensive chemotherapy, had an ECOG performance status of 0-2 and adequate renal and liver function. Patients treated with cytarabine for a pre-existing myeloid disorder, or those with acute promyelocytic leukemia or active CNS involvement with AML were excluded from the study. Venetoclax 600 mg was administered orally once daily on days 2 - 28 of Cycle 1 and days 1 - 28 of subsequent cycles. A 5-day dose ramp-up schedule was followed to reach the 600 mg dose. LDAC 20 mg/m2 was administered s.c. daily on days 1-10 in 28-day cycles. To mitigate the potential risk of tumor lysis syndrome (TLS), all patients were hospitalized and received prophylaxis commencing 48 hours prior to venetoclax during Cycle 1. Adverse events (AEs) were graded by NCI CTCAE Version 4.0. Results: Twenty patients were enrolled in the study (escalation, n=8; expansion, n=12). The median age was 74 years (range: 66 - 87). 8/20 (40%) patients had an antecedent hematologic disorder. Median time on venetoclax was 147.5 days (range: 8 - 455). Grade 3/4 AEs (≥10% patients) excluding cytopenias were febrile neutropenia (35%), hypertension (20%), hypophosphatemia (20%), decreased appetite, increased blood bilirubin, hyponatremia, hypoxia, hypotension, pneumonia, sepsis, syncope, urinary tract infection, and vomiting (10% each). No events of TLS occurred. Venetoclax exposures on Cycle 1 Day 10 (with LDAC) vs. Cycle 1 Day 18 (venetoclax alone) were comparable. The mean ± SD of maximum observed concentration (Cmax, µg/mL/mg) were 2.04 ± 1.45 vs. 2.92 ± 2.15, respectively. The mean ± SD of area under the curve (AUC24, µg*hr/mL) were 33.3 ± 27.5 vs. 46.1 ± 36.8, respectively. Similarly, co-administration of venetoclax did not markedly affect LDAC exposures. The mean ± SD of Cmax (ng/mL) of LDAC on Cycle 1 Day 1 (LDAC alone) vs. Cycle 1 Day 10 (with venetoclax) were 158.89 ± 79.08 vs 166.49 ± 32.06, respectively. Similarly, the mean ± SD of AUCinf (ng*hr/mL) were 170.64 ± 102.86 vs 246.51 ± 93.41, respectively. 15/20 (75%) patients achieved an objective response (CR+CRi+PR). Of them, 14/20 (70%) patients had a CR+CRi; all 14 patients belonged to a subset of 18 patients with no prior myeloproliferative neoplasm (MPN). 16/19 (84%) patients with available data had their bone marrow blast percentage reduced to below 5%. The 12-month overall survival (OS) estimate for all patients was 74.7% (95% CI=49.4 - 88.6) and that for the responders (n=15) was 86.7% (95% CI=56.4 - 96.5). The overall response rates and 12-month OS estimates for patients with or without prior hypomethylating agent (HMA) and with or without MPN are summarized in Table 1. A Kaplan-Meier curve showing OS for responders vs. non-responders is shown in Figure 1. The median time to best response was 30 days (range: 23 - 169). Only 2/14 patients who achieved CR/CRi have died [disease progression (n=1), acute hepatic failure (n=1)]. Conclusions: Venetoclax (600 mg RP2D) plus LDAC demonstrated an acceptable safety and pharmacokenitic profile in patients aged ≥65 years with treatment-naive AML who are not eligible for an intensive anthracycline-containing induction chemotherapy. Clinical remission was achieved in the majority of patients. The median OS has not been reached. A substantially better survival in responders as compared to non-responders suggests that the improvement is likely due to treatment with venetoclax plus LDAC. Updated responses and survival estimates for all patients, including those in dose expansion phase that were enrolled after the preliminary data cut, will be presented. Disclosures Wei: Novartis: Honoraria, Research Funding. Strickland:Boehringer Ingelheim: Consultancy, Research Funding; CTI Biopharma: Consultancy; Daiichi Sankyo: Consultancy; Sanofi: Research Funding; Sunesis Pharmaceuticals: Consultancy, Research Funding; Alexion Pharmaceuticals: Consultancy; Ambit: Consultancy; Baxalta: Consultancy; Abbvie: Research Funding; Astellas Pharma: Research Funding; Celator: Research Funding; Cyclacel: Research Funding; GlaxoSmithKline: Research Funding; Karyopharm Therapeutica: Research Funding. Roboz:Agios, Amgen, Amphivena, Astex, AstraZeneca, Boehringer Ingelheim, Celator, Celgene, Genoptix, Janssen, Juno, MEI Pharma, MedImmune, Novartis, Onconova, Pfizer, Roche/Genentech, Sunesis, Teva: Consultancy; Cellectis: Research Funding. Fiedler:Amgen: Consultancy, Other: Travel, Patents & Royalties, Research Funding; Kolltan: Research Funding; Novartis: Consultancy; Teva: Other: Travel; Ariad/Incyte: Consultancy; Gilead: Other: Travel; Pfizer: Research Funding; GSO: Other: Travel. Martinelli:MSD: Consultancy; Celgene: Consultancy, Speakers Bureau; Ariad: Consultancy, Speakers Bureau; Amgen: Consultancy, Speakers Bureau; Genentech: Consultancy; BMS: Speakers Bureau; Novartis: Speakers Bureau; Roche: Consultancy, Speakers Bureau; Pfizer: Consultancy, Speakers Bureau. Fakouhi:AbbVie Inc.: Employment, Other: may own stock. Darden:AbbVie Inc.: Employment, Other: may own stock. Dunbar:AbbVie Inc.: Employment, Other: may own stock. Zhu:AbbVie Inc.: Employment, Other: may own stock. Agarwal:AbbVie Inc.: Employment, Other: may own stock. Salem:AbbVie Inc.: Employment, Other: Stocks or options. Mabry:AbbVie Inc.: Employment, Other: May own stock. Hayslip:AbbVie Inc.: Employment, Other: May own stock.

Description: Immunotherapy trials targeting the induction of tumor-reactive T-cell responses in cancer patients appear to hold significant promise. Because nonmutated lineage-specific antigens and mutated idiotypic antigens may be coexpressed by tumor cells, the use of autologous tumor material to promote the broadest range of antitumor T-cell specificities has significant clinical potential in cancer vaccination trials. As a model for vaccination in the cancer setting, we chose to analyze the promotion of T-cell responses against Epstein-Barr virus (EBV)-transformed B-lymphoblastoid cell line (B-LCL)–derived antigens in vitro. A series of bulk antigenic formats (freeze–thaw lysate, trifluoroacetic acid lysate, extracted membranes, affinity-purified MHC class I– and class II–presented peptides, acid-eluted peptides) prepared from EBV B-LCLs were tested for their ability to stimulate EBV B-LCL–reactive CD4+ and CD8+ T lymphocytes in vitro when pulsed onto autologous dendritic cells (DCs). DC presentation of freeze–thaw lysate material derived from (either autologous or allogeneic) EBV B-LCLs with an Mr of 10 kd or larger stimulated optimal anti-EBV B-LCL responsiveness from freshly isolated CD4+ and CD8+ peripheral blood T cells. These in vivo “memory” T-cell responses were observed only in EBV-seropositive donors. CD4+ T-cell responses to lysate-pulsed DCs were Th1 type (ie, strong interferon-γ and weak interleukin-5 responses). While CD8+ T-cell responses were also observed in interferon-γ Elispot assays and in cytotoxicity assays, these responses were of low frequency unless the DC stimulators were induced to “mature” after being fed with tumor lysates. Optimal-length, naturally processed, and MHC class I– or class II–presented tumor peptides were comparatively poorly immunogenic in this model system.

Description: Immunotherapy trials targeting the induction of tumor-reactive T-cell responses in cancer patients appear to hold significant promise. Because nonmutated lineage-specific antigens and mutated idiotypic antigens may be coexpressed by tumor cells, the use of autologous tumor material to promote the broadest range of antitumor T-cell specificities has significant clinical potential in cancer vaccination trials. As a model for vaccination in the cancer setting, we chose to analyze the promotion of T-cell responses against Epstein-Barr virus (EBV)-transformed B-lymphoblastoid cell line (B-LCL)–derived antigens in vitro. A series of bulk antigenic formats (freeze–thaw lysate, trifluoroacetic acid lysate, extracted membranes, affinity-purified MHC class I– and class II–presented peptides, acid-eluted peptides) prepared from EBV B-LCLs were tested for their ability to stimulate EBV B-LCL–reactive CD4+ and CD8+ T lymphocytes in vitro when pulsed onto autologous dendritic cells (DCs). DC presentation of freeze–thaw lysate material derived from (either autologous or allogeneic) EBV B-LCLs with an Mr of 10 kd or larger stimulated optimal anti-EBV B-LCL responsiveness from freshly isolated CD4+ and CD8+ peripheral blood T cells. These in vivo “memory” T-cell responses were observed only in EBV-seropositive donors. CD4+ T-cell responses to lysate-pulsed DCs were Th1 type (ie, strong interferon-γ and weak interleukin-5 responses). While CD8+ T-cell responses were also observed in interferon-γ Elispot assays and in cytotoxicity assays, these responses were of low frequency unless the DC stimulators were induced to “mature” after being fed with tumor lysates. Optimal-length, naturally processed, and MHC class I– or class II–presented tumor peptides were comparatively poorly immunogenic in this model system.

Description: Background: We recently showed that the combination of ATRA and arsenic trioxide (ATO) is at least not inferior and possibly superior to standard ATRA and chemotherapy (CHT) in the front-line management of low/intermediate risk APL (Italian-German APL 0406 trial; Lo-Coco et al., NEJM 2013). We report herein on the extended and final series of 276 patients (162 were in the previous report) with the last case being enrolled into the study in January 2013. Methods: The APL0406 study was a prospective, open-label, randomized intergroup trial conducted by the Italian GIMEMA and the German SAL and AMLSG study groups. Eligible patients were adults aged 18-

Description: Locus control region (LCR) sequences are involved in the establishment of open chromosomal domains. To evaluate the possibility of exploiting the human CD2 LCR to regulate gene expression by Moloney murine leukemia virus (Mo-MLV)–based retroviral vectors in T cells, it was included in vectors carrying the enhanced green fluorescence protein (EGFP) reporter gene; then transduction in vitro of lymphoid and nonlymphoid cell lines was performed. Deletion of the viral enhancer in the Mo-MLV long terminal repeat was necessary to detect LCR activity in the context of these retroviral vectors. It was found that a full-length (2.1 kb), but not a truncated (1.0 kb), CD2 LCR retained the ability to modulate reporter gene expression by Mo-MLV–derived retroviral vectors, leading to a homogeneous, unimodal pattern of EGFP expression that remained unmodified in culture over time, specifically in T-cell lines; on the other hand, viral titer was strongly reduced compared with vectors not carrying the LCR. Lentiviral vectors containing the CD2 LCR could be generated at higher titers and were used to analyze its effects on gene expression in primary T cells. Subcutaneous implantation of genetically modified cells in immunodeficient mice showed that retroviral vectors carrying the CD2 LCR conferred an advantage in terms of transgene expression in vivo, compared with the parental vector, by preventing the down-modulation of EGFP expression. These findings suggest a potential application of this LCR to increase gene expression by retroviral and lentiviral vectors in T lymphocytes.

Description: Abstract 1592 Poster Board I-618 Background Previous studies highlighted the importance of the cell adhesion molecule, VLA-4, for chemoresistance and minimal residual disease (MRD) in AML, suggesting promise as therapeutic target. By comparison, the prognostic role of VLA-4 in AML remains controversial with retrospective studies implying either adverse or favorable prognosis. Therefore, we prospectively evaluated VLA-4 expression in participants of a recent Children's Oncology Group (COG) AML pilot protocol. Methods COG-AAML03P1 enrolled 340 newly diagnosed children (aged 1 month - 21 years) with de novo non-acute promyelocytic AML, excluding those with Down syndrome, and tested the feasibility of combining gemtuzumab ozogamicin (GO) with intensive induction chemotherapy followed by GO-containing intensification therapy or matched related donor stem cell transplantation; 216 patients submitted diagnostic marrow specimens for flow cytometric determination of VLA-4 expression that was then correlated with patient demographics, laboratory characteristics, and clinical outcome. Cytogenetics and molecular prognostic markers were used for risk classification as follows: low risk (mutation in core-binding factor, NPM1, or CEBPa; n=73), high risk (-5/5q-, monosomy 7, or FLT3/ITD with high allelic ratio; n=25), or standard risk (all other patients with cytogenetic/molecular data; n=101); 17 patients had insufficient data for risk classification. Results Among the 216 diagnostic specimens, the mean fluorescence intensity (MFI) of VLA-4 expression varied over 35-fold from a baseline of 30 to 1110 (median, 219.5). Patients with high VLA-expression (〉median MFI) were younger (p

Description: Standard first-line therapy for younger patients with peripheral T-cell lymphoma consists of six courses of CHOP or CHOEP consolidated by high-dose therapy and autologous stem cell transplantation (AutoSCT). We hypothesized that consolidative allogeneic transplantation (AlloSCT) could improve outcome. 104 patients with nodal peripheral T-cell lymphoma except ALK+ ALCL, 18 to 60 years of age, all stages and IPI scores except stage 1 and aaIPI 0, were randomized to receive 4 x CHOEP and 1 x DHAP followed by high-dose therapy and AutoSCT or myeloablative conditioning and AlloSCT. The primary endpoint was event-free survival (EFS) at three years. After a median follow-up of 42 months, 3-year EFS of patients undergoing AlloSCT was 43% (95% confidence interval [CI]: 29%; 57%) as compared to 38% (95% CI: 25%; 52%) after AutoSCT. Overall survival at 3 years was 57% (95% CI: 43%; 71%) versus 70% (95% CI: 57%; 82%) after AlloSCT or AutoSCT, without significant differences between treatment arms. None of 21 responding patients proceeding to AlloSCT as opposed to 13 of 36 patients (36%) proceeding to AutoSCT relapsed. Eight of 26 patients (31%) and none of 41 patients died due to transplant-related toxicity after allogeneic and autologous transplantation, respectively. In younger patients with T-cell lymphoma standard chemotherapy consolidated by autologous or allogeneic transplantation results in comparable survival. The strong graft-versus-lymphoma effect after AlloSCT was counterbalanced by transplant-related mortality. CHO(E)P followed by AutoSCT remains the preferred treatment option for transplant-eligible patients. AlloSCT is the treatment of choice for relapsing patients also after AutoSCT.

Description: Background Chronic myeloid leukemia (CML)-study IV was designed to explore whether treatment with imatinib (IM) at 400mg/day (n=400) could be optimized by doubling the dose (n=420), adding IFN (n=430) or cytarabine (n=158) or using IM after IFN-failure (n=128). Methods From July 2002 to March 2012, 1551 newly diagnosed patients in chronic phase were randomized into a 5-arm study. The study was powered to detect a survival difference of 5% at 5 years. The impact of patients' and disease factors on survival was prospectively analyzed. At the time of evaluation, at least 62% of patients still received imatinib, 26.2% were switched to 2nd generation tyrosine kinase inhibitors. Results After a median observation time of 9.5 years, 10-year overall survival was 82%, 10-year progression-free survival 80% and 10-year relative survival 92%. In spite of a faster response with IM800mg, the survival difference between IM400mg and IM800mg was only 3% at 5 years. In a multivariate analysis, the influence on survival of risk-group, major-route chromosomal aberrations, comorbidities, smoking and treatment center (academic vs. other) was significant in contrast to any form of initial treatment optimization. Patients that reached the response milestones 3, 6 and 12 months, had a significant survival advantage of about 6% after 10 years regardless of therapy. The progression probability to blast crisis was 5.8%. Blast crisis was proceeded by high-risk additional chromosomal aberrations. Conclusions For responders, monotherapy with IM400mg provides a close to normal life expectancy independent of the time to response. Survival is more determined by patients' and disease factors than by initial treatment selection. Although improvements are also needed for refractory disease and blast crisis, more life-time can currently be gained by carefully addressing non-CML determinants of survival. Disclosures Hehlmann: Novartis: Research Funding; BMS: Consultancy. Saussele: Pfizer: Honoraria; Incyte: Honoraria; Novartis: Honoraria, Research Funding; BMS: Honoraria, Research Funding. Pfirrmann: BMS: Honoraria; Novartis: Honoraria. Krause: Novartis: Honoraria. Baerlocher: Novartis: Honoraria; BMS: Honoraria; Pfizer: Honoraria. Bruemmendorf: Novartis: Research Funding. Müller: Novartis: Honoraria, Research Funding; BMS: Honoraria, Research Funding; Ariad: Honoraria, Research Funding; Pfizer: Honoraria, Research Funding. Jeromin: MLL Munich Leukemia Laboratory: Employment. Hänel: Roche: Honoraria; Novartis: Honoraria. Burchert: BMS: Honoraria. Waller: Mylan: Consultancy, Honoraria. Mayer: Eisai: Research Funding; Novartis: Research Funding. Link: Novartis: Honoraria. Scheid: Novartis: Honoraria. Schafhausen: Novartis: Honoraria; BMS: Honoraria; Pfizer: Honoraria; Ariad: Honoraria. Hochhaus: Incyte: Research Funding; MSD: Research Funding; Pfizer: Research Funding; Novartis: Research Funding; BMS: Research Funding; ARIAD: Research Funding.

Description: Background: Older patients with acute myeloid leukemia (AML) who are ineligible for intensive chemotherapy are unlikely to achieve remission with available therapy and have unacceptably short survival. Venetoclax (VEN) is a small molecule inhibitor of BCL-2 that achieved remission rates of 〉60% combined with low-dose cytarabine (LDAC). Presented are long-term outcomes, including 1-year overall survival (OS) and biomarker analyses. Methods: This phase 1b/2, open-label study (NCT02287233) evaluates the safety and preliminary efficacy of orally administered VEN combined with LDAC in patients ≥65 years with previously untreated AML (except for hydroxyurea). Patients were ineligible for intensive chemotherapy because of comorbidity or other factors and had an ECOG performance score of 0-2, with adequate hepatic and renal function. Exclusion criteria were acute promyelocytic leukemia, active CNS involvement with AML, concominant use of moderate or strong CYP3A inhibitors, or prior treament with cytarabine for a preexisting myeloid disorder. Prior treatment for myelodysplastic syndrome (MDS) was allowed. In cycle 1, VEN was started at 50 mg/day PO and increased over a 5-day ramp-up to reach the designated cohort dose of 600 or 800 mg/day on day 6, which was continued through day 28. In subsequent cycles, the desingated dose of VEN 600 or 800 mg/day was administered on days 1-28. LDAC 20 mg/m2/day SQ was given on days 1-10 of each cycle. Preliminary efficacy was assessed as the overall response rate (ORR, which included complete remission [CR], CR with incomplete blood count recovery [CRi], and partial remission [PR]). Adverse events (AEs) and laboratory values were monitored. Exploratory analysis of biomarkers (eg, cytogenetics, molecular markers) was performed to identify potential predictors of clinical outcomes. Results: Data cutoff was May 30, 2017. All 71 patients were enrolled ≥1 year prior (46 [65%] male; median age, 74 years [range, 66-87 years]): 10 received VEN 800 mg and 61 received VEN 600 mg, the recommended phase 2 dose. Thirty-three patients (47%) had a history of antecedent hematologic disorder (AHD), most commonly MDS. Among 61 patients given VEN 600 mg, median time on VEN treatment was 6 months (range,