A retrospective comparison of abbreviated course “7+7” vs standard hypomethylating agent plus venetoclax doublets in older/unfit patients with newly diagnosed acute myeloid leukemia.

6507 Background: Hypomethylating agent (HMA) plus venetoclax (VEN) regimens are standard of care in older/chemotherapy ineligible patients with acute myeloid leukemia (AML). While the VEN label recommends continuous 28-day cycles, shortened VEN durations may mitigate cytopenias and improve tolerability. It is unknown how shorter VEN cycles compare to standard HMA+VEN in terms of efficacy/safety. Methods: We performed a retrospective comparison of patients with newly diagnosed (ND) AML treated with azacitidine (AZA) x 7 days plus VEN x 7 days (“7+7” regimen) at 7 French centers (n=82, Willekens, ASH 2022) vs patients treated with standard dose HMA+VEN (s-HMA/VEN) at a US center (n=173), generally consisting of 21-28 days of VEN. We compared composite complete remission rate (CRc, consisting of CR + CRi), overall survival (OS), event-free survival (EFS), and myelosuppression between regimens. Results: Baseline characteristics are shown in the table. The s-HMA-VEN group consisted of 10-day decitabine (DAC) in 59% with the remaining patients receiving 5-day DAC or 7-day AZA. The CRc rate was similar; 72% with “7+7” vs 71% with s-HMA/VEN (p=0.89). The CR rate was 57% with “7+7” vs 55% with s-HMA/VEN (p=0.72). Median cycles to first response was 1 in both groups, however 42% of responders on “7+7” required more than 1 cycle for first response whereas almost all responders on s-HMA-VEN (99%) had a first response after cycle 1. Median cycles to best response was 2 with “7+7” vs 1 with s-HMA-VEN (p=0.02). 4-week mortality was similar (2% with “7+7”, 6% with s-HMA-VEN; p=0.24). 8-week mortality was higher with s-HMA-VEN (17%) compared to “7+7” (6%) (p=0.02). The median OS was 11.2 months (2-year 28%) with “7+7” vs 10.1 months (2-year 33%) with s-HMA/VEN (p=0.93). Outcomes stratified by molecular groups will be updated at the meeting. Fewer patients required platelet transfusions during cycle 1 with “7+7” compared to s-HMA/VEN (62% vs 77%, p=0.01). The cycle 1 rates of neutropenic fever and red cell transfusion requirements were similar. Conclusions: Acknowledging the limitations of a retrospective comparison across multiple centers, we did not observe a signal for a difference in efficacy between "7+7" vs standard VEN-based HMA doublets in ND-AML. The “7+7” regimen was associated with lower platelet transfusion requirements and lower 8-week mortality. Table: see text