Program: Oral and Poster Abstracts
Session: 637. Myelodysplastic Syndromes—Clinical Studies: Lower Risk MDS Clinical Studies
Background: The outcome of patients (pts) with lower-risk myelodysplastic syndrome (MDS) is heterogeneous, with some pts having a particularly poor prognosis. Low doses of hypomethylating agents (HMAs) have been shown to be active in lower-risk MDS. We evaluated the relative safety and efficacy of low-dose decitabine (DAC) and azacitidine (AZA) in pts with lower-risk MDS.
Methods: Adult pts with de novo or secondary low- or intermediate-1-risk MDS, CMML or MDS/MPN were eligible for this study. Pts with prior HMA exposure were excluded. Pts were randomized in a Bayesian adaptive design to receive either AZA 75 mg/m2 IV/SC daily or DAC 20 mg/m2 IV daily for 3 consecutive days on a 28-day cycle; pts were more likely to be assigned to the better performing treatment arm. The primary efficacy outcome was the overall improvement rate (OIR) defined as the composite of complete remission (CR), marrow CR, and hematologic improvement. Secondary outcomes included safety profile, cytogenetic response, conversion to transfusion independence, event-free survival (EFS), and overall survival (OS). EFS was defined as the time to HMA failure, progressive disease, transformation to acute myeloid leukemia (AML) or death from any cause.
Results: Between 11/2012 and 2/2016, 113 pts with lower-risk MDS have been treated, 40 (39%) with AZA and 73 (71%) with DAC. The median age of the entire cohort was 70 years (range, 44-88 years), and the majority of pts (81%) were intermediate-1-risk by IPSS. Baseline characteristics of the 2 treatment groups were well-balanced and are summarized in Table 1.
The median number of cycles received was 9 (range 1-41 cycles). Of the 39 pts in the AZA arm and 70 pts in the DAC arm who have received at least 2 cycles of therapy and were evaluable for response, the OIR was 53% in both groups. The CR rate with AZA and DAC was 38% and 29%, respectively (P=0.29). Among pts with abnormal karyotype at baseline, complete or partial cytogenetic response was observed in 24% of pts in the AZA arm and in 63% of pts in the DAC arm (P=0.01); the rate of complete cytogenetic response was 6% and 26% in the two groups, respectively (P=0.09). Of the 18 pts in the AZA arm and the 38 pts in the DAC arm who were transfusion dependent at baseline and evaluable for response, 17% and 32% achieved transfusion independence, respectively (P=0.24)
The median duration of follow-up for the entire cohort was 20 months (range, 2-42 months). Twenty four pts in the AZA arm (60%) and 23 pts in the DAC arm (32%) have come off study due to lack of response or progressive disease. There was a trend toward prolonged EFS with DAC compared to AZA (median EFS: 19.6 months vs. 13.7 months; 1-year EFS rate: 73% vs. 57, respectively; P=0.15; Figure 1A). Twelve pts in the AZA arm (30%) and 17 pts in DAC arm (23%) have died. The median OS was similar between DAC and AZA (median OS not reached for both; 1-year OS rate: 87% vs. 84%, respectively; P=0.80; Figure 1B). Progression to AML occurred in 5 pts (13%) in the AZA arm and 6 pts (8%) in the DAC arm.
Both agents were overall well-tolerated. Cycle delays were required in 23% and 37% of pts and dose reductions were required in 5% and 12% of pts treated with AZA and DAC, respectively. Infection or neutropenic fever occurred 2 pts (5%) treated with AZA and in 5 pts treated with DAC (7%). No grade 4 adverse events were observed in either treatment arm.
Conclusions: Low-dose AZA and DAC are effective and well-tolerated in pts with lower-risk MDS. Early results suggest that low-dose DAC may result in superior EFS compared to low-dose AZA. A randomized trial comparing low-dose AZA, low-dose DAC, AZA x 5 days, and best supportive care in lower-risk MDS is ongoing.
Disclosures: Jabbour: ARIAD: Consultancy, Research Funding; Pfizer: Consultancy, Research Funding; Novartis: Research Funding; BMS: Consultancy. Daver: Otsuka: Consultancy, Honoraria; Sunesis: Consultancy, Research Funding; BMS: Research Funding; Ariad: Research Funding; Pfizer: Consultancy, Research Funding; Kiromic: Research Funding; Karyopharm: Honoraria, Research Funding. DiNardo: Celgene: Research Funding; Novartis: Other: advisory board, Research Funding; Daiichi Sankyo: Other: advisory board, Research Funding; Abbvie: Research Funding; Agios: Other: advisory board, Research Funding. Pemmaraju: stemline: Consultancy, Honoraria, Research Funding; novartis: Consultancy, Honoraria, Research Funding; LFB: Consultancy, Honoraria; Cellectis: Research Funding; Incyte: Consultancy, Honoraria. Sekeres: Celgene: Membership on an entity's Board of Directors or advisory committees; Millenium/Takeda: Membership on an entity's Board of Directors or advisory committees. Komrokji: Novartis: Consultancy, Speakers Bureau; Celgene: Membership on an entity's Board of Directors or advisory committees, 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.
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