Infectious events in fit patients with relapsed or refractory acute myeloid leukemia treated with azacitidine-venetoclax or intensive chemotherapy

Second-line therapy for relapsed or refractory acute myeloid leukemia (R/R AML) involves either intensive chemotherapy (ICT) or azacitidine and venetoclax (AZAVEN), but their comparative infectious risks are not well established.

This retrospective multicenter study evaluated infectious events in 246 adult R/R AML patients eligible for allogeneic hematopoietic stem-cell transplantation (HSCT) across five French centers from 2015 to 2023.

Of these, 163 received ICT and 83 received AZAVEN, with similar baseline characteristics except for more frequent antifungal prophylaxis in the AZAVEN group (55% vs 28%). A total of 358 infectious events were documented, predominantly during hospitalization (90%). Most infections were severe (grade 3 or 4), with no significant difference in fatal infections between groups. Bloodstream infections without organ involvement (38%) and bacterial infections (49%) were most common. By day 100, the cumulative incidence of a first infection was significantly lower with AZAVEN (37%, 95% CI: 26%-47%) than on ICT (82%, 95% CI: 76%-87%), compared to ICT (HR = 0.23, P < 0.001), confirmed by multivariate analysis. Leukemia control rates were similar between groups.

These results suggest that AZAVEN is associated with lower infectious burden than ICT, while maintaining equivalent anti-leukemic efficacy, supporting its use as a bridging therapy before HSCT in fit R/R AML patients.