The ENHANCE-3 study: venetoclax and azacitidine plus magrolimab or placebo for untreated AML unfit for intensive therapy

Patients with acute myeloid leukemia (AML) ineligible for intensive chemotherapy (IC) have limited treatment options. The phase 3 ENHANCE-3 study aimed to determine whether magrolimab (magrolimab arm) was superior to placebo (control arm) when either was combined with venetoclax and azacitidine. Adults with previously untreated AML who were ineligible for IC were randomized to receive magrolimab (1 mg/kg on days 1 and 4, 15 mg/kg on day 8, 30 mg/kg on days 11 and 15, then weekly for 5 weeks, and then every 2 weeks) or placebo, venetoclax (100 mg on day 1, 200 mg on day 2, and 400 mg daily thereafter), and azacitidine (75 mg/m² days 1-7) in 28-day cycles. The primary end point was overall survival (OS); key secondary end points included complete remission (CR) rate and safety. After randomization of 378 patients, the trial was stopped at a prespecified interim analysis owing to futility. At final analysis, with median follow-up of 7.6 months (magrolimab arm) vs 7.4 months (control arm), median OS was 10.7 vs 14.1 months (hazard ratio, 1.178; 95% confidence interval, 0.848-1.637). The CR rate within 6 cycles was 41.3% vs 46.0%. Addition of magrolimab to venetoclax and azacitidine resulted in more fatal adverse events (19.0% vs 11.4%), primarily driven by grade 5 infections (11.1% vs 6.5%) and respiratory events (2.6% vs 0%). There were similar incidences of any-grade infections, febrile neutropenia, and neutropenia between arms. These results highlight the difficulty in improving outcomes for patients with AML who were ineligible for IC. This trial was registered at www.clinicaltrials.gov as #NCT05079230.