Abstract BACKGROUND The immunologic effects of maintenance therapy in patients (pts) with AML in remission are not well-characterized but of high clinical interest, as rapid recovery of bone marrow (BM) after intensive chemotherapy (IC) may help delay relapse. Post IC, immunological interactions in the BM microenvironment present several immunosuppressive mechanisms. PD-L1 is commonly overexpressed on AML blasts, which is associated with worse prognosis. Oral azacitidine (Oral-AZA [CC-486]) is a hypomethylating agent recently approved in the US for pts with AML in complete remission (CR) or CR with incomplete hematologic recovery (CRi). To better understand the effects of Oral-AZA on immune cells, checkpoint expression of PD-L1/2 on AML blasts and normal myeloid progenitors (MPs), and the kinetics of T cell recovery and activation/exhaustion (eg, PD1, TIM3) were assessed. METHODS Biomarker-evaluable pts aged ≥ 55 years with AML were randomized 1:1 to Oral-AZA 300 mg (n=56) or placebo (PBO, n=52) post IC within 4 months of achieving CR. Flow cytometry evaluations of BM aspirates were performed at screening (ie, baseline [BL]), every 3 cycles until cycle 24 and every 6 cycles thereafter to cycle 36, or as clinically indicated. Correlative analyses of baseline immune parameters with median (med) relapse-free survival (RFS) were computed using Kaplan-Meier methods. RESULTS In the biomarker-evaluable pts, PD-L1 and PD-L2 expression at BL were higher on AML blasts (med intensity 7.1 and 2.9) than normal MPs (0.7 and 1.6). Most AML blasts were PD-L2+ (79%), whereas only 1.9% were PD-L1+. When stratified by the med, higher BL CD3 T cell numbers (as a % of total BM ) were associated with favorable RFS in both Tx arms (Oral-AZA: ≥ med, 562 days[d] and < med, 235d [P = .0308]; PBO: ≥ med, 325d and < med, 155d [P = .0391]). At cycle 3, pts in the Oral-AZA arm had a 1.7-fold increase in CD3 T cells from BL (PBO, 1.1; P = .0450), suggesting Oral-AZA can promote immunologic recovery during early Tx cycles. There was an inverse correlation between T cell exhaustion marker phenotypes (PD1/TIM3+) with CD4 (r = -.5967; P < .0001) and CD8 (r = -.2484; P = .0095) T cell numbers. An increase in RFS was seen in the PBO arm with lower PD1/TIM3+ CD4 numbers (< med, 429d; ≥ med, 155d; P = .0037), with a nominal increase observed in the Oral-AZA arm (< med, 428d; ≥ med, 303d; P = .6764). In a subset of pts, Oral-AZA appeared to suppress CD4 T cell exhaustion (PD1/TIM3+) compared with PBO. CONCLUSIONS Pts in CR/CRi post-IC have a unique immune profile defined by high expression of PD-L1 on a subset of blasts and a high % of PD-L2+ blasts. A higher BL CD3 T cell count after IC in BM was prognostic. Additionally, Oral-AZA appears to contribute to an increase in T cells while also suppressing exhaustion, potentially promoting T cell signaling that could activate functional immune-mediated responses against residual leukemic cells. Citation Format: Daniel L. Menezes, Wendy L. See, Alberto Risueno, Jianglin Ma, Ignazia La Torre, Barry Skikne, CL Beach, Keshava Kumar, Anjan Thakurta. Oral azacitidine modulates the immune microenvironment in acute myeloid leukemia (AML) patients in remission: A subanalysis from the QUAZAR AML-001 Trial [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 505.

BACKGROUND The immunologic effects of maintenance therapy in patients (pts) with AML in remission are not well-characterized but of high clinical interest, as rapid recovery of bone marrow (BM) after intensive chemotherapy (IC) may help delay relapse. Post IC, immunological interactions in the BM microenvironment present several immunosuppressive mechanisms. PD-L1 is commonly overexpressed on AML blasts, which is associated with worse prognosis. Oral azacitidine (Oral-AZA [CC-486]) is a hypomethylating agent recently approved in the US for pts with AML in complete remission (CR) or CR with incomplete hematologic recovery (CRi). To better understand the effects of Oral-AZA on immune cells, checkpoint expression of PD-L1/2 on AML blasts and normal myeloid progenitors (MPs), and the kinetics of T cell recovery and activation/exhaustion (eg, PD1, TIM3) were assessed. METHODS Biomarker-evaluable pts aged ≥ 55 years with AML were randomized 1:1 to Oral-AZA 300 mg (n=56) or placebo (PBO, n=52) post IC within 4 months of achieving CR. Flow cytometry evaluations of BM aspirates were performed at screening (ie, baseline [BL]), every 3 cycles until cycle 24 and every 6 cycles thereafter to cycle 36, or as clinically indicated. Correlative analyses of baseline immune parameters with median (med) relapse-free survival (RFS) were computed using Kaplan-Meier methods. RESULTS In the biomarker-evaluable pts, PD-L1 and PD-L2 expression at BL were higher on AML blasts (med intensity 7.1 and 2.9) than normal MPs (0.7 and 1.6). Most AML blasts were PD-L2+ (79%), whereas only 1.9% were PD-L1+. When stratified by the med, higher BL CD3 T cell numbers (as a % of total BM ) were associated with favorable RFS in both Tx arms (Oral-AZA: ≥ med, 562 days[d] and < med, 235d [P = .0308]; PBO: ≥ med, 325d and < med, 155d [P = .0391]). At cycle 3, pts in the Oral-AZA arm had a 1.7-fold increase in CD3 T cells from BL (PBO, 1.1; P = .0450), suggesting Oral-AZA can promote immunologic recovery during early Tx cycles. There was an inverse correlation between T cell exhaustion marker phenotypes (PD1/TIM3+) with CD4 (r = -.5967; P < .0001) and CD8 (r = -.2484; P = .0095) T cell numbers. An increase in RFS was seen in the PBO arm with lower PD1/TIM3+ CD4 numbers (< med, 429d; ≥ med, 155d; P = .0037), with a nominal increase observed in the Oral-AZA arm (< med, 428d; ≥ med, 303d; P = .6764). In a subset of pts, Oral-AZA appeared to suppress CD4 T cell exhaustion (PD1/TIM3+) compared with PBO. CONCLUSIONS Pts in CR/CRi post-IC have a unique immune profile defined by high expression of PD-L1 on a subset of blasts and a high % of PD-L2+ blasts. A higher BL CD3 T cell count after IC in BM was prognostic. Additionally, Oral-AZA appears to contribute to an increase in T cells while also suppressing exhaustion, potentially promoting T cell signaling that could activate functional immune-mediated responses against residual leukemic cells. Citation Format: Daniel L. Menezes, Wendy L. See, Alberto Risueno, Jianglin Ma, Ignazia La Torre, Barry Skikne, CL Beach, Keshava Kumar, Anjan Thakurta. Oral azacitidine modulates the immune microenvironment in acute myeloid leukemia (AML) patients in remission: A subanalysis from the QUAZAR AML-001 Trial [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 505.

7513 Background: A goal of AML maintenance therapy is to decrease the risk of relapse by suppressing growth of residual leukemic cells post-induction. CC-486 is an oral hypomethylating agent that allows for extended dosing schedules ( >7 days [d]/28d cycle) to sustain therapeutic activity. In the QUAZAR AML-001 trial (NCT01757535), CC-486 maintenance treatment (Tx) significantly prolonged overall (OS) and relapse-free survival vs. placebo (PBO) in pts with AML in first remission following induction chemotherapy (IC), who were not candidates for hematopoietic stem cell transplant (HSCT). Pts initially received CC-486 or PBO for 14d/cycle, but pts who relapsed with 5–15% blasts could receive escalated 21d/cycle dosing. We review outcomes of pts who received 21d dosing in QUAZAR AML-001. Methods: Pts were aged ≥ 55 years, with intermediate- or poor-risk cytogenetics and ECOG PS ≤ 3, and had achieved first CR/CRi after IC ± consolidation. Within 4 mo of CR/CRi, pts were randomized 1:1 to CC-486 300 mg or PBO QD on d 1–14 of 28d Tx cycles. CR/CRi status was assessed every 3 cycles. Pts relapsing with 5%–15% blasts in blood or bone marrow could receive study drug for 21d/cycle at the investigator’s discretion. Tx could continue until > 15% blasts, unacceptable toxicity, or HSCT. Results: 91 patients (CC-486, 51/238 [21%]; PBO, 40/234 [17%]) were assigned to ≥ 1 21d/cycle dosing schedule. Median time to dose escalation was 9.2 mo (range 1.0-52.7) for CC-486 and 6.0 mo (0.5-19.3) for PBO. Median number of 21d dosing cycles was 2.0 (range 1-45) in the CC-486 arm and 2.0 (1-16) in the PBO arm; 43% and 18% of pts, respectively, received > 3 cycles of 21d dosing. Among 78 evaluable pts, 10/43 (23%) CC-486 pts and 4/35 (11%) PBO pts regained CR/CRi (central review) during dose escalation. Median OS from randomization was 22.8 mo vs. 14.6 mo with CC-486 vs. PBO, respectively (HR 0.66 [95%CI 0.42, 1.0]; P = 0.073), and 1-year survival rates were 80.4% vs. 59.5% (+20.9% [95%CI 2.1%, 39.7%]). The most common AEs with first onset during 21d dosing were febrile neutropenia (CC-486 24%, PBO 3%), thrombocytopenia (22%, 23%), anemia (22%, 20%), and neutropenia (20%, 10%). Conclusions: Escalated 21d CC-486 dosing was well tolerated and resulted in prolongation of OS and restoration of remission in approximately one-fourth of pts. Hematologic AEs first reported during escalated dosing in both Tx arms may be due in part to disease relapse. A 21d dosing schedule should be considered for pts receiving CC-486 who experience relapse with 5–15% blasts. Clinical trial information: NCT01757535 .

BACKGROUND: In newly diagnosed AML, high remission rates are typically achieved with IC, but the response is often transient, and detectable residual disease in the bone marrow post-chemotherapy is predictive of early relapse. Emerging data show that the identification of ≥ 0.1% MRD by multiparameter flow cytometry (MFC) in patients with AML in remission after IC is an important prognostic marker that may help guide treatment (Tx) decisions. CC-486 is an oral hypomethylating agent that allows for extended dosing schedules to prolong drug exposure over the Tx cycle. In the QUAZAR AML-001 Maintenance Trial, Tx with CC-486 300 mg QD for 14 days/28-day Tx cycle was associated with significantly improved overall (OS) and relapse-free survival (RFS) vs. placebo (PBO) in patients (pts) with AML in first remission after induction chemotherapy ± consolidation. Samples for MFC were obtained prior to randomization and serially throughout the study to assess the impact of MRD on OS and RFS, and to evaluate rates of conversion from MRD positivity (+) to negativity (-) in the CC-486 and PBO arms. METHODS: Eligible pts aged ≥ 55 years with AML were randomized 1:1 to CC-486 300 mg or PBO within 4 months of achieving first complete remission (CR) or CR with incomplete blood count recovery (CRi). MFC assessments of bone marrow aspirates were performed centrally at screening; at cycles 3, 6, 9, 12, 15, 18, 21, 24, 30, and 36; and as clinically indicated. Samples were analyzed with a panel of 22 cell surface markers using an MRD+ cutoff of ≥ 0.1% (per ELN MRD guidelines). For pts MRD+ at baseline (BL; ie, at randomization), an MRD response was defined as achievement of MRD- for ≥ 2 consecutive assessments. MRD- duration was calculated from the time of randomization (for pts MRD- at BL) or from the first of ≥ 2 consecutive MRD- tests (for pts MRD+ at BL), until the last MRD- assessment (for pts who became MRD+) or Tx discontinuation. OS, RFS, and MRD- durations were estimated using Kaplan-Meier methods. Multivariate (MV) Cox regression analyses were performed to evaluate the association of BL MRD status (MRD+ vs. MRD-) and randomized Tx arm (CC-486 vs. PBO) with OS and RFS. RESULTS: The MRD-evaluable cohort comprised 463/472 randomized pts (98.1%; CC-486, n=236; PBO, n=227) who had samples available for evaluation at BL and at ≥ 1 post-BL visit. At BL, 43% of pts (n=103) in the CC-486 arm and 50% (n=116) in the PBO arm were MRD+. Overall, BL characteristics were similar between MRD+ and MRD- pts: median ages were 69 (range 55-84) and 68 (55-86) years, respectively; 84% and 88% had intermediate-risk cytogenetics at diagnosis; 52% and 46% of pts had an ECOG PS of 0; and 79% and 82% received ≥ 1 cycle of consolidation after induction. CC-486 Tx resulted in improved OS from time of randomization compared with PBO in pts who were either MRD+ (median 14.6 vs. 10.4 mo, respectively; HR 0.69 [95%CI 0.51, 0.93]) or MRD- (median 30.1 vs. 24.3 mo; HR 0.81 [0.59, 1.12]) at BL. Median RFS was also extended with CC-486 vs. PBO for both MRD+ (7.1 vs. 2.7 mo, respectively; HR 0.58 [95%CI 0.43, 0.78]) and MRD- pts (13.4 vs. 7.8 mo; HR 0.71 [0.52, 0.98]). In MV analyses, BL MRD status (MRD+ vs. MRD-) was significantly associated with OS (HR 1.85; P < 0.0001) and RFS (HR 2.04; P < 0.0001), and CC-486 showed a significant Tx benefit vs. PBO on both OS (HR 0.74; P = 0.0067) and RFS (HR 0.63; P < 0.0001) independent of MRD status at BL (Figure). The median duration of MRD negativity was extended with CC-486 vs. PBO: 11.0 vs. 5.0 mo, respectively (HR 0.62 [95%CI 0.48, 0.78]). Tx with CC-486 also resulted in a higher rate of MRD response (MRD+ to MRD-) vs. PBO: 37% vs. 19%, respectively. Among MRD responders, 9/38 patients (24%) in the CC-486 arm achieved MRD negativity > 6 mo after randomization, compared with only 1/22 patients (5%) in the PBO arm. CONCLUSIONS: The QUAZAR AML-001 Maintenance Trial was the first prospective, randomized trial to include long-term longitudinal assessment of MRD in older patients with AML in remission. In both treatment arms, MRD+ status (≥ 0.1%) after induction ± consolidation was associated with significantly shorter OS and RFS compared with MRD- status. Approximately one-fourth of MRD responders treated with CC-486 achieved MRD negativity > 6 mo after study entry, suggesting that CC-486 could induce MRD negativity after prolonged MRD+ status. Maintenance Tx with CC-486 substantially improved OS and RFS independent of MRD status at BL. Disclosures Roboz: Otsuka: Consultancy; AstraZeneca: Consultancy; Orsenix: Consultancy; Astellas: Consultancy; Argenx: Consultancy; Actinium: Consultancy; Sandoz: Consultancy; Roche/Genentech: Consultancy; Jazz: Consultancy; Eisai: Consultancy; Celltrion: Consultancy; MEI Pharma: Consultancy; Helsinn: Consultancy; Epizyme: Consultancy; Jasper Therapeutics: Consultancy; Cellectis: Research Funding; Trovagene: Consultancy; Takeda: Consultancy; Astex: Consultancy; Amphivena: Consultancy; Agios: Consultancy; Abbvie: Consultancy; Pfizer: Consultancy; Novartis: Consultancy; Janssen: Consultancy; Celgene: Consultancy; Bayer: Consultancy; Array BioPharma: Consultancy; Daiichi Sankyo: Consultancy. Ravandi:Abbvie: Consultancy, Honoraria, Research Funding; Xencor: Consultancy, Honoraria, Research Funding; AstraZeneca: Consultancy, Honoraria; Macrogenics: Research Funding; Jazz Pharmaceuticals: Consultancy, Honoraria, Research Funding; Astellas: Consultancy, Honoraria, Research Funding; Celgene: Consultancy, Honoraria; BMS: Consultancy, Honoraria, Research Funding; Amgen: Consultancy, Honoraria, Research Funding; Orsenix: Consultancy, Honoraria, Research Funding. Wei:Pfizer: Honoraria; Bristol Myers Squibb: Honoraria, Research Funding, Speakers Bureau; Janssen: Honoraria; Walter and Eliza Hall Institute of Medical Research: Patents & Royalties: AW is eligible for royalty payments related to venetoclax; Roche: Honoraria; Amgen: Honoraria, Research Funding; Novartis: Honoraria, Research Funding, Speakers Bureau; Abbvie: Honoraria, Research Funding, Speakers Bureau; Servier: Consultancy, Honoraria, Research Funding; Macrogenics: Honoraria; Astra Zeneca: Honoraria, Research Funding. Dombret:Menarini: Consultancy; Janssen: Consultancy; Cellectis: Consultancy; Shire-Baxalta: Consultancy; Immunogen: Consultancy; Otsuka: Consultancy; Abbvie: Consultancy; Astellas: Consultancy; Daiichi Sankyo: Consultancy; Servier: Consultancy, Research Funding; Sunesis: Consultancy; Amgen: Consultancy, Research Funding; Jazz Pharma: Consultancy, Research Funding; Celgene: Consultancy; Nova: Consultancy, Research Funding; Incyte: Consultancy, Research Funding; Pfizer: Consultancy, Research Funding. Döhner:Astex: Consultancy, Honoraria; Astellas: Consultancy, Honoraria, Research Funding; AROG: Research Funding; Amgen: Consultancy, Honoraria, Research Funding; Agios: Consultancy, Honoraria, Research Funding; Abbvie: Consultancy, Honoraria; AstraZeneca: Consultancy, Honoraria; GEMoaB: Consultancy, Honoraria; Celgene: Consultancy, Honoraria, Research Funding; Janssen: Consultancy, Honoraria; Novartis: Consultancy, Honoraria, Research Funding; Oxford Biomedicals: Consultancy, Honoraria; Sunesis: Research Funding; Pfizer: Research Funding; Roche: Consultancy, Honoraria; Jazz: Consultancy, Honoraria, Research Funding; Helsinn: Consultancy, Honoraria; Bristol Myers Squibb: Consultancy, Honoraria, Research Funding. Thol:Abbvie: Membership on an entity's Board of Directors or advisory committees; Celgene: Membership on an entity's Board of Directors or advisory committees; Pfizer: Membership on an entity's Board of Directors or advisory committees; Astellas: Membership on an entity's Board of Directors or advisory committees; Daiichi Sankyo: Membership on an entity's Board of Directors or advisory committees. Voso:Bristol Myers Squibb: Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding. Porkka:Novartis: Consultancy, Honoraria, Research Funding; BMS/Celgene: Honoraria, Research Funding. La Torre:Bristol Myers Squibb: Current Employment, Current equity holder in publicly-traded company. Skikne:Bristol Myers Squibb: Current Employment. Kumar:Bristol Myers Squibb: Current Employment, Current equity holder in publicly-traded company. Dong:Bristol Myers Squibb: Current Employment, Current equity holder in publicly-traded company. Beach:Bristol Myers Squibb: Current Employment, Current equity holder in publicly-traded company. Risueño:Bristol Myers Squibb: Current Employment, Current equity holder in publicly-traded company, Patents & Royalties: Named in BMS (before Celgene) patent filings related to predictive patient response biomarkers in hematological malignancies. Lopes de Menezes:Bristol Myers Squibb: Current Employment, Current equity holder in publicly-traded company. Ossenkoppele:Novartis: Consultancy, Research Funding; Genentech: Consultancy, Research Funding; Celgene: Consultancy, Research Funding; Roche: Consultancy; J&J: Consultancy, Research Funding; Agios: Consultancy; Jazz: Consultancy; Astellas: Consultancy; Daiichi Sayko: Consultancy; Amgen: Consultancy.

BACKGROUND: AML is an aggressive malignancy primarily affecting older individuals. Although 40%-60% of patients (pts) aged >60 years attain complete remission (CR) with IC, 80%-90% of them eventually relapse. In the continuum of AML care, the greatest expenditures are associated with relapsed/refractory disease, and hospitalization is the largest component (~70%) of direct AML healthcare costs (Pandya, 2020). In the randomized, phase III QUAZAR AML-001 Maintenance Trial, CC-486, an oral hypomethylating agent, significantly prolonged overall (OS) and relapse-free survival (RFS) vs. placebo (PBO) in pts with newly diagnosed (ND) AML in first remission following IC. OBJECTIVE: Determine rates of hospitalization and days in hospital with CC-486 and PBO in QUAZAR AML-001, and quantify associated costs of hospitalization using unit costs estimated from a US claims database. METHODS: In QUAZAR AML-001, eligible pts were age ≥55 years, with de novo or secondary AML, intermediate- or poor-risk cytogenetics, and ECOG PS ≤3; achieved first CR or CR with incomplete count recovery (CRi) after IC ± consolidation; and were not candidates for hematopoietic stem cell transplant (HSCT). Within 4 months of CR/CRi, pts were randomized 1:1 to CC-486 300 mg or PBO, administered once-daily on days 1-14 of repeated 28-day cycles. Pts who received ≥1 dose of study drug were followed for hospitalizations and durations of stay from date of informed consent through 28 days after last dose. The mean number of days hospitalized per month (30 days) in each treatment arm was computed by dividing the aggregate number of hospitalized days by the number of ongoing pts at each time-point. Rates of hospitalization and days in hospital were also adjusted for duration of CC-486 and PBO exposure. 95% confidence intervals (CI) for relative risk (RR) estimates and associated P values are based on asymptotic methods. Patients with a primary diagnosis of AML, preceded by ≥6 months (baseline) without a claim for AML were identified in the IBM MarketScan Commercial & Medicare database from April 2013 to July 2019. A stepwise procedure was then used to include pts aged ≥55 years at diagnosis, without a diagnosis of another primary cancer or HSCT, and with insurance coverage during the entire 6-month baseline period. Unit cost of hospitalization was derived as the average total AML-related hospitalization costs incurred per day of stay, adjusted for inflation to 2019 US dollars. RESULTS: In all, 469 pts were enrolled in QUAZAR AML-001 and received CC-486 (N=236) or PBO (N=233). Total exposure to CC-486 was 363.8 pt-years (PY) and to PBO was 234.9 PY. In all, 108 pts (45.8%) in the CC-486 arm and 118 (50.6%) in the PBO arm were hospitalized. The total numbers of hospitalizations were 173 in the CC-486 arm and 151 in the PBO arm; however, the exposure-adjusted rate of hospitalization was significantly lower in the CC-486 arm: 0.48/PY vs. 0.64/PY, respectively (RR 0.740 [95%CI 0.595, 0.920]; P = 0.0068) (Table). The total number of days hospitalized was 2872 in the CC-486 arm and 3139 in the PBO arm, and the exposure-adjusted days-in-hospital rate was significantly lower in the CC-486 arm (7.89/PY vs. 13.36/PY in the PBO arm; RR 0.591 [95%CI 0.562, 0.621]; P < 0.0001) (Table). Of the ND-AML cohort identified in the MarketScan database, 3058 pts had ≥ 1 noncapitated hospitalization and provided the basis for estimated hospitalization-related costs. Median age and sex distribution of these pts were generally consistent with those of pts in QUAZAR AML-001. The mean AML-related hospitalization cost incurred in the database was $7,126/day (2019 USD). Thus, based on exposure-adjusted days-in-hospital rates in the CC-486 and PBO arms (7.89/PY and 13.36/PY, respectively), the estimated mean costs of hospitalization in QUAZAR AML-001 were $56,224/PY in the CC-486 arm and $95,201/PY in the PBO arm. Cumulative cost savings in the CC-486 arm compared with PBO ranged from $2,837 in month 2 to $40,909 by month 24 (Figure). CONCLUSION: CC-486 was associated with significantly reduced exposure-adjusted risk of hospitalization and days in hospital compared with PBO, which are estimated to result in substantial cumulative cost savings. Significantly prolonged RFS with CC-486 vs. PBO in this study (10.2 vs. 4.8 months; P = 0.0001) may translate into substantial economic benefits, with lower hospitalization-related costs due to reduced rates of hospitalization and days in hospital. Disclosures Oliva: Alexion: Consultancy; Apellis: Consultancy; Abbvie: Consultancy; Amgen: Consultancy; Novartis: Consultancy; BMS: Consultancy, Honoraria, Patents & Royalties, Speakers Bureau. Oriol:Amgen: Consultancy, Speakers Bureau; Janssen: Consultancy; Sanofi: Membership on an entity's Board of Directors or advisory committees; GlaxoSmithKline: 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, Speakers Bureau. La Torre:Bristol Myers Squibb: Current Employment, Current equity holder in publicly-traded company. Skikne:Bristol Myers Squibb: Current Employment. Beach:Bristol Myers Squibb: Current Employment, Current equity holder in publicly-traded company. Kumar:Bristol Myers Squibb: Current Employment, Current equity holder in publicly-traded company. Dong:Bristol Myers Squibb: Current Employment, Current equity holder in publicly-traded company. Chen:Bristol Myers Squibb: Current Employment, Current equity holder in publicly-traded company. Ranjan:SmartAnalyst India Pvt. Ltd.: Current Employment. Kiendrebeogo:SmartAnalyst, Inc.: Current Employment. Braun:Servier: Research Funding; Daiichy-Sankyo: Honoraria.

7533 Background: Effective AML maintenance treatment (Tx) should decrease the risk of relapse and prolong survival without compromising HRQoL. In the placebo (PBO)-controlled phase III QUAZAR AML-001 trial (NCT01757535), CC-486, an oral hypomethylating agent, provided significant improvements in overall (OS) and relapse-free survival (RFS) in patients (pts) with AML in first remission following IC. Here we present pt-reported HRQoL outcomes from that study. Methods: Eligible pts were ≥ 55 yrs of age with intermediate- or poor-risk cytogenetics and ECOG PS ≤ 3, and in CR/CRi after IC ± consolidation. Pts were randomized 1:1 to CC-486 300 mg or PBO QD on days (d) 1–14 of 28d Tx cycles. HRQoL was assessed by FACIT-Fatigue scale and EQ-5D-3L health utility index, completed on d1 of each cycle and at end of Tx (EOT). Endpoints include Tx differences in mean changes from baseline (BL), and proportions of pts with clinically meaningful change from BL (improvement, no change, deterioration). Evaluable pts had an HRQoL assessment at BL and ≥ 1 post-BL visit. Stratified ANCOVA models included Tx and BL scores as covariates. Results: In all, 225/238 pts (95%) in the CC-486 arm were evaluable for FACIT-Fatigue and EQ-5D-3L, and 219/234 pts (94%) in the PBO arm were evaluable for FACIT-Fatigue and 217 (93%) for EQ-5D-3L. Pt characteristics were comparable between Tx arms. Most pts (61%) were 65-74 yrs of age. Median number of CC-486 Tx cycles was 12 and PBO cycles was 7. Compliance rates were > 95% at BL and remained high ( > 85%) at all post-BL visits except for EOT. At BL, pts in both Tx arms had comparable low levels of fatigue and generally good HRQoL relative to an age-matched general population. There were no meaningful differences between CC-486 and PBO in mean changes from BL in FACIT-Fatigue or EQ-5D-3L scores at any post-BL visit. There was no statistically significant difference between Tx arms in proportion of pts with a clinically meaningful deterioration in FACIT-Fatigue score at any post-BL visit except at cycle 29 (likely due to chance; no adjustment made for multiple testing), or in EQ-5D-3L at any visit. Median time to deterioration was not significantly different between CC-486 and PBO on the FACIT-Fatigue scale (41 vs 44 weeks, respectively; P = 0.70) or the EQ-5D-3L (200 vs 164 weeks; P = 0.63). Conclusions: HRQoL and low levels of fatigue were preserved with CC-486 maintenance Tx. CC-486 significantly improved OS and RFS while maintaining HRQoL comparable to PBO. Clinical trial information: NCT01757535 .

BACKGROUND Although induction chemotherapy results in remission in many older patients with acute myeloid leukemia (AML), relapse is common and overall survival is poor. METHODS We conducted a phase 3, randomized, double-blind, placebo-controlled trial of the oral formulation of azacitidine (CC-486, a hypomethylating agent that is not bioequivalent to injectable azacitidine), as maintenance therapy in patients with AML who were in first remission after intensive chemotherapy. Patients who were 55 years of age or older, were in complete remission with or without complete blood count recovery, and were not candidates for hematopoietic stem-cell transplantation were randomly assigned to receive CC-486 (300 mg) or placebo once daily for 14 days per 28-day cycle. The primary end point was overall survival. Secondary end points included relapse-free survival and health-related quality of life. RESULTS A total of 472 patients underwent randomization; 238 were assigned to the CC-486 group and 234 were assigned to the placebo group. The median age was 68 years (range, 55 to 86). Median overall survival from the time of randomization was significantly longer with CC-486 than with placebo (24.7 months and 14.8 months, respectively; P<0.001). Median relapse-free survival was also significantly longer with CC-486 than with placebo (10.2 months and 4.8 months, respectively; P<0.001). Benefits of CC-486 with respect to overall and relapse-free survival were shown in most subgroups defined according to baseline characteristics. The most common adverse events in both groups were grade 1 or 2 gastrointestinal events. Common grade 3 or 4 adverse events were neutropenia (in 41% of patients in the CC-486 group and 24% of patients in the placebo group) and thrombocytopenia (in 22% and 21%, respectively). Overall health-related quality of life was preserved during CC-486 treatment. CONCLUSIONS CC-486 maintenance therapy was associated with significantly longer overall and relapse-free survival than placebo among older patients with AML who were in remission after chemotherapy. Side effects were mainly gastrointestinal symptoms and neutropenia. Quality-of-life measures were maintained throughout treatment. (Supported by Celgene; QUAZAR AML-001 ClinicalTrials.gov number NCT01757535.)

7530 Background: About 40-50% of older patients (pts) with AML attain complete remission (CR) with induction chemotherapy (IC) but relapse is common.Effective, well-tolerated maintenance treatment (Tx) is needed for older pts in remission who are not eligible for hematopoietic stem cell transplant (HSCT). CC-486 is an oral hypomethylating agent that allows for extended dosing schedules ( >7 days [d]/cycle) to sustain therapeutic activity. In the phase III placebo (PBO)-controlled QUAZAR AML-001 trial (NCT01757535), CC-486 maintenance therapy in pts with AML in first remission following IC produced significant improvements in overall and relapse-free survival. Here we report safety and tolerability findings among pt subgroups defined by age at study entry. Methods: Eligible pts were ≥ 55 yrs of age, with de novo or secondary AML, intermediate or poor risk cytogenetics, and ECOG PS ≤ 3; had achieved first CR or CRi after IC ± consolidation; and were not candidates for HSCT. Within 4 mo of CR/CRi, pts were randomized 1:1 to CC-486 300 mg or PBO QD on d 1–14 of repeated 28d Tx cycles. Safety was assessed across 3 age subgroups (≥ 55 to < 65, ≥ 65 to < 75, and ≥ 75 yrs) in pts who received ≥ 1 dose of study drug. Adverse events (AEs) were coded using MedDRA v. 22.0 and graded by NCI-CTCAE v. 4.0. Results: 469 pts ( >99% of all enrolled pts) were evaluable for safety (CC-486 n = 236; PBO n = 233). Median age was 68 yrs (range 55-86). Age distribution was similar between the two Tx arms (Table). Between Tx arms, AE rates within each age stratum were similar to rates in the overall study population. The most common AEs (any grade) with CC-486 were GI events, which were more frequent than in the PBO arm across age groups. Within the CC-486 arm, AE rates were generally consistent across age groups, except for constipation, which was > 20% more frequent in pts aged ≥ 75 yrs, and thrombocytopenia, which was ≥ 20% less frequent in this group (Table). Overall, 13% and 4% of pts in the CC-486 and PBO groups discontinued Tx due to AEs. Conclusions: In QUAZAR AML-001, CC-486 was generally well tolerated in all age groups, including elderly pts aged ≥ 75 yrs. Clinical trial information: NCT01757535 . [Table: see text]

Introduction: Many older patients (pts) with AML respond to intensive induction chemotherapy (IC), but responses are often short-lived and overall survival (OS) is poor. The benefit of post-remission maintenance treatment (Tx) for pts with AML is unclear, as no therapy has shown to significantly improve OS. CC-486 is an oral hypomethylating agent that allows for prolonged drug exposure during each Tx cycle to sustain therapeutic activity. We hypothesized that prolonged Tx with CC-486 could be effective as post-remission maintenance in AML. Herein, we report the primary results of QUAZAR AML-001 (NCT01757535), a phase III international, randomized, double-blind, placebo (PBO)-controlled study evaluating CC-486 as maintenance therapy in pts aged ≥55 years with AML in first remission following IC. Methods: Eligible pts had de novo or secondary AML, intermediate- or poor-risk cytogenetics, and Eastern Cooperative Oncology Group performance status (ECOG PS) scores of ≤3; had achieved first complete remission (CR) or CR with incomplete count recovery (CRi) after IC, with or without consolidation chemotherapy; and were not candidates for hematopoietic stem-cell transplant (HSCT). Within 4 months of attaining CR/CRi, pts were randomized 1:1 to receive CC-486 300 mg or PBO once-daily on days 1-14 of repeated 28-day Tx cycles. A 21-day dosing schedule was permitted for pts who experienced AML relapse with 5-15% blasts in blood or bone marrow while on-study. Tx could continue indefinitely until the presence of >15% blasts, unacceptable toxicity, or HSCT. The primary endpoint was OS. Secondary endpoints included relapse-free survival (RFS), health-related quality of life (HRQoL), and safety. Samples were collected for exploratory translational endpoints, including measurable residual disease (MRD). Kaplan-Meier estimates of OS and RFS were compared for CC-486 vs. PBO by stratified log-rank test. Hazard ratios (HRs) and 95% confidence intervals (CIs) were generated using a stratified Cox proportional hazards model. Results: Between May 2013 and October 2017, 472 pts were randomized to receive CC-486 (n=238) or PBO (n=234). Baseline characteristics were balanced between Tx arms. Median age was 68 years (range 55-86), 91% of pts had de novo AML, and 86% and 14% of pts, respectively, had intermediate-risk or poor-risk cytogenetics. Following induction, 81% of pts achieved a CR and 19% achieved CRi; 80% of pts had received consolidation chemotherapy (45% received 1 consolidation cycle and 31% received 2 consolidation cycles). At a median follow-up of 41.2 months, OS was significantly improved with CC-486 vs. PBO: median OS was 24.7 months vs. 14.8 months from time of randomization, respectively (P=0.0009; HR 0.69 [95%CI 0.55, 0.86]) (FigureA). RFS was also significantly prolonged: median RFS was 10.2 months in the CC-486 arm, compared with 4.8 months in the PBO arm (P=0.0001; HR 0.65 [95%CI 0.52, 0.81]) (Figure B). OS and RFS benefits of CC-486 were demonstrated regardless of baseline cytogenetic risk, the number of prior consolidation cycles received, and CR/CRi status. CC-486 did not adversely impact overall HRQoL vs. PBO, as assessed by mean changes from baseline in HRQoL measures during Tx. CC-486 had a manageable safety profile generally consistent with that of injectable azacitidine. Median exposure to CC-486 was 12 cycles (range 1-80) and to PBO was 6 cycles (1-73). The most frequently reported adverse events (AEs) with CC-486 and PBO were grade 1 or 2 gastrointestinal (GI) events, including nausea (64% and 23%, respectively), vomiting (59% and 10%), and diarrhea (49% and 21%). The most common grade 3-4 AEs were neutropenia (CC-486, 41%; PBO, 24%), thrombocytopenia (23% and 22%), and anemia (14% and 13%). Serious AEs were infrequent, mainly infections, which occurred in 17% of pts in the CC-486 arm and 8% of pts in the PBO arm. Few AEs led to Tx discontinuation, most often GI events (CC-486, 5%; PBO, 0.4%). Conclusions: CC-486 is the first therapy used in the maintenance setting to provide statistically significant and clinically meaningful improvements in both OS and RFS in pts with AML in remission following induction chemotherapy, with or without consolidation. Oral CC-486 has a manageable safety profile and represents a new therapeutic standard for pts with AML in remission. Disclosures Wei: Abbvie: Honoraria, Membership on an entity's Board of Directors or advisory committees, Other: AHW is a former employee of the Walter and Eliza Hall Institute and receives a fraction of its royalty stream related to venetoclax, Research Funding, Speakers Bureau; Macrogenics: Honoraria, Membership on an entity's Board of Directors or advisory committees; Pfizer: 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; Janssen: Honoraria; Servier: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Celgene: Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Amgen: Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Astra Zeneca: Honoraria, Research Funding; Novartis: Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding, Speakers Bureau; Genentech: Honoraria, Membership on an entity's Board of Directors or advisory committees. Döhner:AbbVie, Agios, Amgen, Astellas, Astex, Celator, Janssen, Jazz, Seattle Genetics: Consultancy, Honoraria; AROG, Bristol Myers Squibb, Pfizer: Research Funding; Celgene, Novartis, Sunesis: Honoraria, Research Funding. Montesinos:Abbvie: Membership on an entity's Board of Directors or advisory committees; Celgene: Consultancy, Membership on an entity's Board of Directors or advisory committees, Other: Research support, Speakers Bureau; Daiichi Sankyo: Consultancy, Membership on an entity's Board of Directors or advisory committees, Other: Research support, Speakers Bureau; Incyte: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Janssen: Membership on an entity's Board of Directors or advisory committees, Other: Research support, Research Funding, Speakers Bureau; Karyopharm: Membership on an entity's Board of Directors or advisory committees, Other: Research support; Novartis: Membership on an entity's Board of Directors or advisory committees, Other: Research support, Research Funding, Speakers Bureau; Pfizer: Membership on an entity's Board of Directors or advisory committees, Other: Research support, Research Funding, Speakers Bureau; Teva: Membership on an entity's Board of Directors or advisory committees, Other: Research support, Research Funding, Speakers Bureau. Ravandi:BMS: Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Agios: Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Novartis: Honoraria, Membership on an entity's Board of Directors or advisory committees; Orsenix: Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Abbvie: Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Astellas: Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Celgene: Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Xencor: Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Amgen: Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Macrogenix: Membership on an entity's Board of Directors or advisory committees, Research Funding. Sayar:Celgene Corporation: Membership on an entity's Board of Directors or advisory committees. Porkka:Celgene: Consultancy, Research Funding; Daiichi Sankyo: Consultancy, Research Funding; Novartis: Consultancy, Research Funding. Selleslag:Celyad: Consultancy; Novartis: Consultancy, Honoraria, Speakers Bureau; Celgene: Consultancy, Honoraria, Speakers Bureau; Pfizer: Consultancy, Honoraria, Speakers Bureau; Astellas: Consultancy; Daichii Sankyo: Consultancy; Janssen-Cilag: Consultancy, Honoraria, Speakers Bureau; Amgen: Consultancy, Honoraria, Speakers Bureau; Astex Otsuka: Consultancy, Honoraria; Takeda: Consultancy, Honoraria, Speakers Bureau; Incyte: Consultancy, Honoraria, Speakers Bureau. Sandhu:Takeda: Consultancy; Amgen: Consultancy; Novartis: Consultancy; Bioverativ: Consultancy; Celgene Corporation: Consultancy; Pfizer: Consultancy; Janssen: Consultancy. Giai:BMS: Honoraria; Pfizer: Honoraria; Novartis: Honoraria. Beltrami:Ospedale Policlinico San Martino: Employment. Ossenkoppele:Celgene Corporation: Consultancy, Honoraria, Research Funding. La Torre:Celgene Corporation: Employment, Equity Ownership. Skikne:Celgene Corporation: Employment, Equity Ownership. Kumar:Celgene Corporation: Employment, Equity Ownership. Dong:Celgene Corporation: Employment, Equity Ownership. Beach:Celgene Corporation: Employment, Equity Ownership. Roboz:AbbVie: Consultancy, Membership on an entity's Board of Directors or advisory committees; Actinium: Consultancy, Membership on an entity's Board of Directors or advisory committees; Agios: Consultancy, Membership on an entity's Board of Directors or advisory committees; Amphivena: Consultancy, Membership on an entity's Board of Directors or advisory committees; Argenx: Consultancy, Membership on an entity's Board of Directors or advisory committees; Astex: Consultancy, Membership on an entity's Board of Directors or advisory committees; Astellas: Consultancy, Membership on an entity's Board of Directors or advisory committees; Bayer: Consultancy, Membership on an entity's Board of Directors or advisory committees; Celgene: Consultancy, Membership on an entity's Board of Directors or advisory committees; Celltrion: Consultancy, Membership on an entity's Board of Directors or advisory committees; Daiichi Sankyo: Consultancy, Membership on an entity's Board of Directors or advisory committees; Eisai: Consultancy, Membership on an entity's Board of Directors or advisory committees; Janssen: Consultancy, Membership on an entity's Board of Directors or advisory committees; Jazz: Consultancy, Membership on an entity's Board of Directors or advisory committees; Novartis: Consultancy, Membership on an entity's Board of Directors or advisory committees; MEI Pharma: Consultancy, Membership on an entity's Board of Directors or advisory committees; Orsenix: Consultancy, Membership on an entity's Board of Directors or advisory committees; Otsuka: 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; Roche/Genentech: Consultancy, Membership on an entity's Board of Directors or advisory committees; Sandoz: Consultancy, Membership on an entity's Board of Directors or advisory committees; Takeda: Consultancy, Membership on an entity's Board of Directors or advisory committees; Trovagene: Consultancy, Membership on an entity's Board of Directors or advisory committees.

Background: Approximately 40-60% of older patients (pts) with AML achieve complete remission (CR) with IC. Factors influencing the use of consolidation after induction include disease-related considerations, extent of hematopoietic recovery, pt fitness, and physician and pt preference. Most older pts who achieve AML remission will experience disease relapse despite consolidation therapy (Schlenk, Haematologica, 2018). In the phase III, randomized, double-blind QUAZAR AML-001 Maintenance Trial, CC-486, an oral hypomethylating agent, was shown to significantly prolong OS and RFS vs. placebo (PBO) in pts with AML in first remission following induction ± consolidation. Prior to study entry, the use of consolidation chemotherapy and number of consolidation cycles was at the discretion of the treating physician, with study eligibility not contingent on the use of consolidation. Objective: Assess survival outcomes in the QUAZAR AML-001 trial in pt subgroups defined by number of consolidation courses received before study entry. Methods: Eligible pts were aged ≥55 years with newly diagnosed AML, intermediate- or poor-risk cytogenetics, and ECOG PS ≤3. Within 4 months (mo) of attaining first CR or CR with incomplete blood count recovery (CRi), pts were randomized 1:1 to CC-486 300 mg or PBO QD for 14 days per 28-day treatment (Tx) cycle. OS and RFS were compared among pts who received no consolidation ("No Consolidation"), 1 cycle of consolidation ("1 Consolidation"), or ≥2 cycles of consolidation ("≥2 Consolidations"). For these analyses, "induction" and "consolidation" defined regimens received before and after, respectively, the reported date of first CR/CRi. OS was defined as the time from randomization to death, and RFS as time from randomization to relapse or death. Kaplan-Meier OS/RFS estimates were compared for CC-486 vs. PBO using log-rank test. Hazard ratios (HRs) and 95% CIs were generated using a stratified Cox proportional hazards model. These analyses were not powered sufficiently to determine statistical significance. Results: 472 pts were randomized to CC-486 (N=238) or PBO (N=234). Most pts (80%) received consolidation before study entry. The No Consolidation cohort comprised 94 pts (20%; CC-486 52, PBO 42), the 1 Consolidation cohort comprised 212 pts (45%; CC-486 110, PBO 102), and the ≥2 Consolidations cohort comprised 166 pts (35%; CC-486 76, PBO 90), including 19 pts (CC-486 6, PBO 13) who received 3 consolidation cycles. Common agents used for consolidation were cytarabine (377/378 pts), idarubicin (95/378), and daunorubicin (37/378). While most pts received 1 induction, 97 pts received ≥2 induction courses; of them, 21 (CC-486 14, PBO 7) did not receive consolidation and 76 (CC-486 43, PBO 33) received ≥1 consolidation cycle. Baseline characteristics (eg, CR / CRi after IC, ECOG PS, cytogenetic risk at diagnosis) were generally similar among Tx arms and cohorts. Median (range) ages of pts in the 0 / 1 / ≥2 Consolidation cohorts were 71 (58-84), 68 (55-86), and 67 (55-82) years, respectively. In the No Consolidation cohort, median OS from the time of randomization with CC-486 vs. PBO was 23.3 vs. 10.9 mo, respectively (HR 0.55 [95%CI 0.34, 0.89]), and median RFS was 8.4 vs. 3.9 mo (0.55 [0.34, 0.88]) (Figure A). In the 1 Consolidation cohort, median OS was 21.0 vs. 14.3 mo with CC-486 vs. PBO, respectively (HR 0.75 [95%CI 0.55, 1.02]), and median RFS was 10.0 vs. 4.7 mo (0.72 [0.53, 0.99]) (Figure B). In the ≥2 Consolidations cohort, median OS was 28.6 mo with CC-486 vs. 17.6 mo with PBO (HR 0.75 [95%CI 0.50, 1.11]), and median RFS was 13.0 vs. 6.1 mo (0.59 [0.41, 0.87]) (Figure C). Conclusions: CC-486 was associated with consistent survival benefits vs. PBO regardless of number of prior consolidation cycles. Use of consolidation was generally associated with nominal improvements in OS and RFS within each Tx arm; however, in the CC-486 arm, median OS for pts who did not receive consolidation was similar to those who received 1 consolidation cycle (23.3 and 21.0 mo, respectively). Results should be interpreted with caution, as these cohorts were not prospectively defined and the study was not powered to detect significant differences between subgroups. Nevertheless, these data clearly suggest that older pts with AML in first remission after induction can benefit from CC-486, regardless of their fitness to receive consolidation or the number of consolidation cycles received before starting CC-486. Disclosures Wei: AMGEN: Honoraria, Other: Advisory committee, Research Funding; Walter and Eliza Hall Institute: Patents & Royalties; Novartis: Honoraria, Research Funding, Speakers Bureau; Abbvie: Honoraria, Other: Advisory committee, Research Funding, Speakers Bureau; Genentech: Honoraria, Other: Advisory committee; Servier: Consultancy, Honoraria, Other: Advisory committee; Astellas: Honoraria, Other: Advisory committee; Pfizer: Honoraria, Other: Advisory committee; Macrogenics: Honoraria, Other: Advisory committee; Celgene: Honoraria, Other: Advisory committee, Speakers Bureau; Astra-Zeneca: Honoraria, Other: Advisory committee, Research Funding; Janssen: Honoraria, Other. Roboz:Orsenix: Consultancy; Actinium: Consultancy; Argenx: Consultancy; Jazz: Consultancy; Astex: Consultancy; Celgene: Consultancy; Janssen: Consultancy; Novartis: Consultancy; Pfizer: Consultancy; Bayer: Consultancy; Array BioPharma: Consultancy; Abbvie: Consultancy; Agios: Consultancy; Astellas: Consultancy; Daiichi Sankyo: Consultancy; AstraZeneca: Consultancy; Jasper Therapeutics: Consultancy; Cellectis: Research Funding; Otsuka: Consultancy; Takeda: Consultancy; Trovagene: Consultancy; Eisai: Consultancy; Celltrion: Consultancy; Epizyme: Consultancy; Helsinn: Consultancy; MEI Pharma: Consultancy; Sandoz: Consultancy; Roche/Genentech: Consultancy; Amphivena: Consultancy. Dombret:Sunesis: Consultancy; Abbvie: Consultancy; Shire-Baxalta: Consultancy; Immunogen: Consultancy; Otsuka: Consultancy; Janssen: Consultancy; Menarini: Consultancy; Pfizer: Consultancy, Research Funding; Jazz Pharma: Consultancy, Research Funding; Celgene: Consultancy; Nova: Consultancy, Research Funding; Incyte: Consultancy, Research Funding; Astellas: Consultancy; Servier: Consultancy, Research Funding; Amgen: Consultancy, Research Funding; Daiichi Sankyo: Consultancy; Cellectis: Consultancy. Döhner:Janssen: Consultancy, Honoraria; Celgene: Consultancy, Honoraria, Research Funding; Bristol Myers Squibb: Consultancy, Honoraria, Research Funding; Astex: Consultancy, Honoraria; Astellas: Consultancy, Honoraria, Research Funding; AROG: Research Funding; Amgen: Consultancy, Honoraria, Research Funding; Agios: Consultancy, Honoraria, Research Funding; Abbvie: Consultancy, Honoraria; Sunesis: Research Funding; Oxford Biomedicals: Consultancy, Honoraria; Pfizer: Research Funding; Roche: Consultancy, Honoraria; Novartis: Consultancy, Honoraria, Research Funding; Helsinn: Consultancy, Honoraria; Jazz: Consultancy, Honoraria, Research Funding; AstraZeneca: Consultancy, Honoraria; GEMoaB: Consultancy, Honoraria. Selleslag:Amgen: Consultancy, Honoraria, Speakers Bureau; MSD: Consultancy, Honoraria, Speakers Bureau; Pfizer: Consultancy, Honoraria, Speakers Bureau; Incyte: Consultancy, Honoraria; GSK: Consultancy, Honoraria; Sanofi: Consultancy, Honoraria; Alexion: Consultancy, Honoraria; Astellas: Consultancy, Honoraria, Speakers Bureau; Celgene: Consultancy, Honoraria, Speakers Bureau; Novartis: Consultancy, Honoraria, Speakers Bureau; Janssen Cilag: Consultancy, Honoraria, Speakers Bureau; AbbVie: Consultancy, Honoraria, Speakers Bureau; Belgian College: Membership on an entity's Board of Directors or advisory committees; Teva: Consultancy, Honoraria, Speakers Bureau; Takeda: Consultancy, Honoraria, Speakers Bureau. La Torre:Bristol Myers Squibb: Current Employment, Current equity holder in publicly-traded company. Skikne:Bristol Myers Squibb: Current Employment. Kumar:Bristol Myers Squibb: Current Employment, Current equity holder in publicly-traded company. Dong:Bristol Myers Squibb: Current Employment, Current equity holder in publicly-traded company. Beach:Bristol Myers Squibb: Current Employment, Current equity holder in publicly-traded company. Ravandi:Macrogenics: Research Funding; Astellas: Consultancy, Honoraria, Research Funding; Amgen: Consultancy, Honoraria, Research Funding; BMS: Consultancy, Honoraria, Research Funding; Celgene: Consultancy, Honoraria; Abbvie: Consultancy, Honoraria, Research Funding; Orsenix: Consultancy, Honoraria, Research Funding; Xencor: Consultancy, Honoraria, Research Funding; Jazz Pharmaceuticals: Consultancy, Honoraria, Research Funding; AstraZeneca: Consultancy, Honoraria.

BACKGROUND: CC-486, a DNA hypomethylating agent and epigenetic modifier, is an oral formulation of azacitidine (AZA) that is administered at lower exposures for extended durations (300 mg/day [d] for 14 or 21d/28d cycle) compared with the injectable formulation of AZA, which is given in a high exposure, limited duration regimen of 75mg/m2 for 7d/28d cycle. AZA induces DNA damage and cytotoxicity, and promotes changes in gene expression leading to cellular differentiation. As DNA incorporation of AZA is S-phase-dependent, it has been hypothesized that extended dosing with CC-486 prolongs drug exposure and DNA incorporation to enhance epigenetic activity. The mechanism of action imparted by extended dosing schedules of CC-486 is not fully understood. In patients with myeloid malignancies, DNA hypomethylation in blood is sustained throughout the 28d Tx cycle with extended CC-486 dosing regimens (Laille, 2015; Garcia-Manero, 2016). To better understand the mechanism of CC-486, we assessed the kinetics of expression of myeloid markers of cellular differentiation and cytotoxicity with various AZA dosing schedules in in vitro and in vivo models of AML. METHODS: AML cell lines (AML-193, KG1a, and MV4-11) were treated in vitro with AZA (0.05 - 5 µM daily for 5d or 15d), and at cumulative concentrations of 1 or 3 µM administered once or fractionated over 2-5d to experimentally model CC-486 extended exposures: 1 µM cumulative dose (1 µM × 1d, 0.5 µM × 2d, 0.33 µM × 3d, 0.25 µM × 4d, or 0.2 µM × 5d); 3 µM cumulative dose (3 µM × 1d, 1.5 µM × 2d, 1 µM × 3d, 0.75 µM × 4d, or 0.6 µM × 5d). AZA- or vehicle-treated cells were analyzed by flow cytometry, DNA methylation (Illumina Infinium EPIC assay), and RNA-Seq. Temporal expression of CD11b was assessed as a surface marker of myeloid differentiation, and Annexin-V staining was used to determine the extent of apoptosis and cell death. In efficacy studies, mouse models of AML (syngeneic, cell line-derived xenografts) were treated intraperitoneally with AZA regimens at 1 mg/kg/d × 15d (extended) or 3 mg/kg/d x 5d. RESULTS: Tx of AML-193 cells with 0.05 - 5 µM daily AZA led to upregulation of markers of myeloid differentiation (including CD11b) at lower doses, and a dose-dependent increase in apoptosis up to 7d after Tx initiation. Following Tx with 1 µM AZA for 1d, maximal cellular differentiation (ie, CD11b expression) occurred at d3 in 30% of AML-193 cells; conversely, cells treated with 0.2 µM/d AZA for 5d showed greater differentiation (40%) peaking on d7 (Fig A). CD11b expression was increased upon each subsequent cell division; after 5 cell divisions, CD11b upregulation was 4-fold higher in cells treated with multiple, lower AZA doses than with 1 µM AZA administered for 1d (Fig B). CD11b upregulation was not observed in the absence of cell division under serum starvation conditions for 3d (to induce cell cycle arrest), further suggesting that cell division is a requirement for AZA-induced CD11b changes (Fig C). Similarly, AML-193 cells treated with a 3 µM cumulative AZA dose over 1, 2, 3, 4, or 5d showed greater changes in myeloid differentiation marker expression, with peak apoptosis at d7 with extended dosing regimens (Fig D). In KG1a and MV4-11 cells, Tx with 1 µM AZA QD for 5d led to induction of myeloid differentiation by d7, and cell death (followed by recovery of undifferentiated cells) by d28. In contrast, daily Tx with 0.3 µM AZA for 15d led to slower, more robust upregulation of differentiation markers, peaking at d21 and accompanied by a gradual loss of cell viability. Extended AZA exposure to cells led to pronounced changes in gene expression (Fig E) and DNA methylation (Fig F) at both d7 (immune response gene signature) and d28 (cell adhesion gene signature) compared with limited duration exposure AZA. In mice, low exposure, extended regimens of AZA exhibited higher DNA and RNA incorporation into peripheral blood mononuclear cells (PBMCs) and bone marrow cells when compared with higher exposure, limited duration regimens. Extended AZA dosing led to significant efficacy in murine AML models. CONCLUSIONS: In AML cell lines, low exposure, extended duration AZA schedules modeling CC-486 induced robust changes in differentiation. These results suggest that CC-486-mediated effects using extended exposure regimens preferentially promote a differentiation effect and cell death of AML tumor cells. These mechanistic insights may help inform rational CC-486 combination Tx strategies. Disclosures Dunshee: Bristol Myers Squibb: Current equity holder in publicly-traded company, Ended employment in the past 24 months; Genentech Inc.: Current Employment, Current equity holder in publicly-traded company. Dai:Bristol Myers Squibb: Current Employment, Current equity holder in publicly-traded company. Jang:Bristol Myers Squibb: Ended employment in the past 24 months. Risueño:Bristol Myers Squibb: Current Employment, Current equity holder in publicly-traded company, Patents & Royalties: Named in BMS (before Celgene) patent filings related to predictive patient response biomarkers in hematological malignancies. Jeyaraju:Bristol Myers Squibb: Current Employment, Current equity holder in publicly-traded company. Hagner:Bristol Myers Squibb: Current Employment, Current equity holder in publicly-traded company. See:Bristol Myers Squibb: Current Employment, Current equity holder in publicly-traded company. MacBeth:Bristol Myers Squibb: Current Employment, Current equity holder in publicly-traded company. Wang:Bristol Myers Squibb: Current Employment, Current equity holder in publicly-traded company. La Torre:Bristol Myers Squibb: Current Employment, Current equity holder in publicly-traded company. Skikne:Bristol Myers Squibb: Current Employment. Beach:Bristol Myers Squibb: Current Employment, Current equity holder in publicly-traded company. Kumar:Bristol Myers Squibb: Current Employment, Current equity holder in publicly-traded company. Thakurta:Oxford University: Other: visiting professor; Bristol Myers Squibb: Current Employment, Current equity holder in publicly-traded company. Lopes de Menezes:Bristol Myers Squibb: Current Employment, Current equity holder in publicly-traded company.

INTRODUCTION: About 50% of older patients with AML attain remission with intensive induction chemotherapy (IC) but the majority will eventually relapse. Effective, well tolerated maintenance treatments are needed to reduce the risk of relapse and prolong survival for older patients with AML in remission, who are less likely than younger patients to be candidates for hematopoietic stem cell transplant (HSCT). CC-486 is an oral hypomethylating agent that allows for extended dosing schedules to sustain therapeutic activity. In the randomized, phase III QUAZAR AML-001 Maintenance Trial, CC-486 significantly prolonged overall survival (OS) and relapse-free survival (RFS) vs. placebo in patients aged ≥55 years with AML in first remission after IC ± consolidation. Gastrointestinal (GI) events were the most common treatment-emergent adverse events (TEAEs) reported in patients who received CC-486. Here we assess the rates of GI TEAEs and associated management strategies over time with CC-486 treatment in QUAZAR AML-001. METHODS: Eligible patients were aged ≥55 years and had AML with intermediate- or poor-risk cytogenetics and Eastern Cooperative Oncology Group performance status (ECOG PS) scores ≤3. Patients had achieved complete remission (CR) or CR with incomplete blood count recovery (CRi) after IC ± consolidation and were not candidates for HSCT. Within 4 months of achieving CR/CRi, patients were randomized 1:1 to CC-486 300 mg or placebo, administered once-daily on days 1-14 of repeated 28-day treatment cycles. Safety was assessed among patients who received ≥1 dose of study drug, from the date of first dose through 28 days after the last dose. Prophylaxis and treatment of GI TEAEs were allowed but not mandatory. RESULTS: In all, 236 patients received CC-486 and were evaluated for safety. The median age at study entry was 68 years (range 55-86), 202 patients (85.6%) had intermediate-risk cytogenetics at diagnosis, 185 (78.4%) had achieved CR after induction, and 184 (78.0%) received ≥1 course of consolidation before randomization. Overall, nausea, vomiting, and diarrhea (any grade) were reported in 65%, 60%, and 50%, respectively, of patients treated with CC-486. Few patients experienced grade 3 TEAEs (nausea, 3%; vomiting, 3%; diarrhea, 5%) or serious events (0.4%, 0.8%, and 1.3%, respectively), and only 1 grade 4 event (diarrhea) was reported at any time on-study. Rates of GI TEAEs were highest during initial treatment and decreased thereafter. In cycles 1-2, 3-4, and 5-6, respectively, nausea was reported in 53%, 17%, and 15% of patients; vomiting in 49%, 15%, and 10% of patients; and diarrhea in 29%, 16%, and 11% of patients (Figure). The most commonly used concomitant GI medications were 5-HT3 antagonists, metoclopramide, lactulose, and loperamide; use of these agents was also highest during the first 2 treatment cycles and decreased over time (Figure). GI events required CC-486 treatment interruptions for 13% of patients, dose-reductions for 6% of patients, and treatment discontinuation for 5% of patients. DISCUSSION: Most GI-related TEAEs reported by patients treated with CC-486 were low-grade, and events decreased in frequency after initial treatment cycles, indicating these events were well managed. Use of GI medications decreased concurrently, suggesting progressive GI tolerance to CC-486 with continued therapy. Few patients discontinued CC-486 due to GI TEAEs. Prophylaxis and symptomatic intervention of GI events during early CC-486 therapy may facilitate treatment adherence to promote better outcomes. Disclosures Ravandi: Amgen: Consultancy, Honoraria, Research Funding; BMS: Consultancy, Honoraria, Research Funding; Astellas: Consultancy, Honoraria, Research Funding; Orsenix: Consultancy, Honoraria, Research Funding; Abbvie: Consultancy, Honoraria, Research Funding; Macrogenics: Research Funding; AstraZeneca: Consultancy, Honoraria; Jazz Pharmaceuticals: Consultancy, Honoraria, Research Funding; Xencor: Consultancy, Honoraria, Research Funding; Celgene: Consultancy, Honoraria. Selleslag:Alexion: Consultancy, Honoraria; GSK: Consultancy, Honoraria; Teva: Consultancy, Honoraria, Speakers Bureau; Sanofi: Consultancy, Honoraria; Astellas: Consultancy, Honoraria, Speakers Bureau; Pfizer: Consultancy, Honoraria, Speakers Bureau; Incyte: Consultancy, Honoraria; Takeda: Consultancy, Honoraria, Speakers Bureau; Novartis: Consultancy, Honoraria, Speakers Bureau; Janssen Cilag: Consultancy, Honoraria, Speakers Bureau; AbbVie: Consultancy, Honoraria, Speakers Bureau; Belgian College: Membership on an entity's Board of Directors or advisory committees; Amgen: Consultancy, Honoraria, Speakers Bureau; MSD: Consultancy, Honoraria, Speakers Bureau; Celgene: Consultancy, Honoraria, Speakers Bureau. Sayar:Bristol Myers Squibb: Membership on an entity's Board of Directors or advisory committees. Safah:Amgen: Honoraria; Astellas: Speakers Bureau; Verastem: Honoraria; Janssen: Speakers Bureau. Hiwase:Novartis Australia: Research Funding. La Torre:Bristol Myers Squibb: Current Employment, Current equity holder in publicly-traded company. Skikne:Bristol Myers Squibb: Current Employment. Kumar:Bristol Myers Squibb: Current Employment, Current equity holder in publicly-traded company. Dong:Bristol Myers Squibb: Current Employment, Current equity holder in publicly-traded company. Beach:Bristol Myers Squibb: Current Employment, Current equity holder in publicly-traded company. Dombret:Otsuka: Consultancy; Abbvie: Consultancy; Servier: Consultancy, Research Funding; Sunesis: Consultancy; Amgen: Consultancy, Research Funding; Jazz Pharma: Consultancy, Research Funding; Celgene: Consultancy; Nova: Consultancy, Research Funding; Incyte: Consultancy, Research Funding; Pfizer: Consultancy, Research Funding; Daiichi Sankyo: Consultancy; Astellas: Consultancy; Menarini: Consultancy; Janssen: Consultancy; Cellectis: Consultancy; Shire-Baxalta: Consultancy; Immunogen: Consultancy.

Thrombocytopenia is among the strongest predictors of decreased survival for patients with myelodysplastic syndromes (MDS) across all prognostic risk groups. The safety and efficacy of CC-486 (oral azacitidine) was investigated in early-phase studies; we assessed clinical outcomes among subgroups of MDS patients from these studies, defined by presence or lack of pretreatment thrombocytopenia (<= 75 x 10(9)/L platelet count). Patients received CC-486 300 mg once-daily for 14 or 21 days of repeated 28-day cycles. Overall, 81 patients with MDS, median age 72 years, comprised the Low Platelets (n = 45) and High Platelets (n = 36) cohorts. Pretreatment median platelet counts were 34 x 10(9)/L and 198 x 10(9)/L, respectively. Grade 3-4 bleeding events occurred in 2 patients in the Low Platelets and 1 patient in the High Platelets groups; events resolved without sequelae. Treatment-related mortality was reported for 7 patients, 5 of whom had pretreatment platelet values < 25 x 10(9)/L. Overall response rates were 38% and 46% in the Low Platelets and High Platelets groups, respectively. Five thrombocytopenic patients attained complete remission and 9 attained platelet hematologic improvement. In both cohorts, platelet counts dropped during the first CC-486 treatment cycle, then increased thereafter. Extended CC-486 dosing was generally well tolerated and induced hematologic responses in these patients regardless of pretreatment thrombocytopenia.

Abstract Background: Injectable HMAs (azacitidine [AZA], decitabine) are the standard of care in higher-risk myelodysplastic syndromes (HR-MDS) (NCCN, 2016). When other treatment (Tx) options are no longer feasible, HMAs may be used to treat patients (pts) with lower-risk MDS (LR-MDS) and have demonstrated efficacy in older pts with newly diagnosed acute myeloid leukemia (AML) (Dombret, Blood, 2015; Kantarjian, JCO, 2012). Injectable HMAs induce hematologic response or improvement (HI) in ~50% of pts (Grinblatt, Haematologica, 2014; Lyons, JCO, 2009; Silverman, JCO, 2002), but responses may lack durability. There are no standard Tx options indicated for use after HMA failure; the mainstay of Tx in this setting for pts ineligible for stem cell transplant is a clinical trial or supportive care. CC-486, the oral formulation of AZA, was evaluated in 3 phase 1/2 studies that did not exclude pts who had received HMA Tx before study entry. Aim: Determine clinical outcomes for pts with MDS, chronic myelomonocytic leukemia (CMML), or AML, treated with CC-486 monotherapy who had previously failed injectable HMA Tx. Methods: Pts with MDS, CMML, or AML from 3 phase 1/2 CC-486 studies (2 of which included dose-finding periods) who had received HMA Tx before receiving CC-486 are included in these analyses. CC-486 Tx regimens were: 120-600mg x7 days (d) following a single SC AZA cycle (75mg/m2/d x7d), or 300mg QD or 200mg BID x14d or 21d (with no initial SC AZA cycle). All dosing regimens were administered in repeated 28d cycles. Overall response rate (ORR) included complete remission (CR), partial remission (PR), CR with incomplete hematologic recovery (CRi; AML pts only), HI, and transfusion independence (TI). Marrow CR (mCR) was assessed in MDS pts with ≥5% bone marrow blasts at baseline. Results: In all, 40 pts had received prior HMA Tx: 26 pts with MDS, 2 with CMML, and 12 with AML. In the MDS/CMML and AML groups, respectively, median ages were 75 years (range 55-84) and 71 years (60-93) and median times since diagnosis were 28 (2-140) and 4 (0-32) months (Table). Before receiving CC-486, 12 pts (30%) had failed >1 prior injectable HMA course. Most pts (58%) had previously received >4 HMA Tx cycles. Six pts with AML (50%) had received prior HMAs for Tx of antecedent MDS. Of 29 pts for whom outcomes with prior HMAs were known, 16 pts relapsed and 13 pts were refractory to the injectable HMA. The median number of CC-486 Tx cycles was 5 (range 1-52). For all pts treated with CC-486, ORR was 35%. ORR and rates of specific responses were similar between pts with MDS/CMML and pts with AML (Figure). Five of 13 pts (38%) who were refractory to prior HMAs responded, including 1 AML pt who attained CR with CC-486. Six of 16 pts (38%) who had relapsed during or after prior HMA Tx responded. During CC-486 Tx, 32% of pts attained any HI and 31% achieved RBC TI. Of pts who had received ≥6 cycles of prior HMA Tx (n=20), ORR was 35% (7/20). ORR was not statistically different between 7d (n=26) and extended (n=14) CC-486 dosing (P=0.288). The most frequent (≥10%) grade 3-4 hematologic TEAEs were anemia (33%), thrombocytopenia (23%), neutropenia (15%), and febrile neutropenia (10%); the most frequent grade 3-4 gastrointestinal TEAEs were diarrhea and vomiting (10% each). Conclusions: Among pts who were relapsed or refractory to prior HMA Tx, 35% had a hematologic response to CC-486, suggesting that prior HMA failure does not preclude future response to CC-486. Notably, the majority of pts had received >4 prior HMA Tx cycles; thus, prior failures to injectable HMAs were not likely due to inadequate duration of Tx. The ORR with CC-486 in pts who had received ≥6 cycles of the prior injectable HMA was the same as the ORR with CC-486 in all pts. Hypomethylating effects of HMAs are transient; unlike injectable HMAs, oral CC-486 can be administered over extended dosing periods (>7d) of the Tx cycle to produce sustained hypomethylating activity. There was no statistical difference in ORR between CC-486 7d and extended dosing in this small pt group. Nevertheless, given the short half-life and S-phase-restricted DNA incorporation of AZA (Li, Cancer Res, 1970), extending AZA exposure to >7d/cycle with CC-486 could increase the opportunity for cycling cells to incorporate AZA and expose more malignant progenitor cells to AZA, which may optimize therapeutic effects. Extended hypomethylation due to longer exposure to CC-486 may induce pts to respond to CC-486 who had failed prior injectable HMA Tx. Disclosures Savona: TG Therapeutics: Research Funding; Takeda: Research Funding; Sunesis: Research Funding; Incyte: Membership on an entity's Board of Directors or advisory committees, Research Funding; Celgene: Membership on an entity's Board of Directors or advisory committees; Gilead: Membership on an entity's Board of Directors or advisory committees; Amgen Inc.: Membership on an entity's Board of Directors or advisory committees; Ariad: Membership on an entity's Board of Directors or advisory committees. Gore:Celgene: Consultancy, Honoraria, Research Funding. Scott:Celgene: Consultancy, Membership on an entity's Board of Directors or advisory committees; Novartis: Consultancy, Research Funding, Speakers Bureau; Alexion: Speakers Bureau; Agios: Membership on an entity's Board of Directors or advisory committees. Cogle:Celgene: Membership on an entity's Board of Directors or advisory committees. Conkling:USOncology Research: Research Funding; Amgen Inc.: Research Funding. Hetzer:Celgene: Employment, Equity Ownership. Dong:Celgene: Employment, Equity Ownership. Kumar:Celgene: Employment, Equity Ownership. Ukrainskyj:Celgene: Employment, Equity Ownership. Skikne:Celgene: Employment, Equity Ownership.

UNLABELLED:CC-486 (oral azacitidine) is an epigenetic modifier in development for patients with myelodysplastic syndromes and acute myeloid leukemia. In part 1 of this two-part study, a 7-day CC-486 dosing schedule showed clinical activity, was generally well tolerated, and reduced DNA methylation. Extending dosing of CC-486 beyond 7 days would increase duration of azacitidine exposure. We hypothesized that extended dosing would therefore provide more sustained epigenetic activity. Reported here are the pharmacokinetic (PK) and pharmacodynamic (PD) profiles of CC-486 extended dosing schedules in patients with myelodysplastic syndromes (MDS), chronic myelomonocytic leukemia (CMML) or acute myeloid leukemia (AML) from part 2 of this study. PK and/or PD data were available for 59 patients who were sequentially assigned to 1 of 4 extended CC-486 dosing schedules: 300mg once-daily or 200mg twice-daily for 14 or 21 days per 28-day cycle. Both 300mg once-daily schedules and the 200mg twice-daily 21-day schedule significantly (all P < .05) reduced global DNA methylation in whole blood at all measured time points (days 15, 22, and 28 of the treatment cycle), with sustained hypomethylation at cycle end compared with baseline. CC-486 exposures and reduced DNA methylation were significantly correlated. Patients who had a hematologic response had significantly greater methylation reductions than non-responding patients. These data demonstrate that extended dosing of CC-486 sustains epigenetic effects through the treatment cycle.TRIAL REGISTRATION:ClinicalTrials.gov NCT00528983.

Background: When administered subcutaneously (SC), the epigenetic modifier, azacitidine (AZA) is shown to improve overall survival in patients (pts) with AML compared with conventional care regimens (Fenaux, JCO, 2010; Dombret, Blood, 2015). CC-486, the oral formulation of AZA, is in clinical development for use in hematologic malignancies. An early dose-finding study of CC-486 administered on a 7-day schedule showed it to be safe and clinically active in pts with AML (Garcia-Manero, JCO, 2011; Gore, Blood, 2011). Extending CC-486 dosing for more than 7 days may increase AZA exposure to leukemic cells over the treatment (Tx) cycle to improve response.

TPS7097 Background: Few inroads have been made in the past 30 years to improve overall survival (OS) in older patients (pts) with AML. While induction chemotherapy (IC) can induce CR in 40-50% of older pts, most relapse within 3-18 months. Post-remission therapy (Tx) is required to prevent relapse. Parenteral azacitidine (AZA) prolonged OS in older pts with AML vs conventional care regimens (10.4 vs 6.5 months, P= 0.1009) (Dombret, Haematologica, 2014:LB2433). CC-486 is an oral formulation of AZA in development for use in hematologic malignancies. An oral formulation allows delivery of AZA at lower systemic doses over a more prolonged schedule than is practical with SC AZA. CC-486 taken at home is convenient for pts, eliminates injection- and catheter-site reactions, and avoids resource utilization costs of hospital/clinic visits. Thus, CC-486 may offer a relapse-free survival (RFS) advantage and improve quality of life. The Quazar phase 3 AML Maintenance trial (clinicaltrials.gov NCT01757535) is designed to assess whether CC-486 is an effective low-intensity maintenance Tx that can extend OS in older pts with AML. Methods: Pts aged ≥ 55 yrs with de novo AML or AML secondary to MDS in first CR or CRi (IWG 2003) after IC, with or without consolidation, are randomized 1:1 to 300 mg QD CC-486 or placebo for 14 days of 28-day treatment cycles. Randomization is stratified by age (55-64 / ≥ 65 yrs) and cytogenetic risk (Intermediate / Poor) at induction, prior MDS, and post-remission consolidation Tx. All pts can receive supportive care. The primary endpoint is OS. Secondary endpoints include RFS, time to relapse, time to discontinuation, and safety. Exploratory analyses assess molecular and cellular markers of minimal residual disease during maintenance Tx that may be predictive of clinical outcomes. Enrollment began in May 2013, with a target of 460 pts from 150 global sites. Accrual is designed to allow enough events for ≥ 90% power to detect a statistically significant treatment effect on OS (n = 330 deaths; expected duration 60 months). By Jan 2015, 168 pts had been randomized. Study enrollment continues through 2016. Clinical trial information: NCT01757535.