Post-transplant outcomes stratified by induction therapy in patients with AML undergoing allogeneic transplantation.

e18572 Background: Allogeneic hematopoietic cell transplantation (allo-HCT) remains the only curative option for patients with higher-risk acute myeloid leukemia (AML); however, transplant failure occurs in approximately 40% of cases, most commonly due to relapse. Post-transplant outcomes are influenced by multiple factors, but the impact of pre-transplant induction regimen remains unclear. Methods: We retrospectively analyzed adults with AML who underwent allo-HCT at our institution between January 2015 and January 2025. Patients were grouped by induction regimen prior to transplant into three cohorts: anthracycline plus cytarabine (anthracycline-based), hypomethylating agent plus venetoclax (HMA/VEN), and CPX-351. OS and RFS were calculated using Kaplan–Meier. Induction groups were matched using inverse probability of treatment weighting (IPTW) based on age, sex, ELN 2022 risk category, and conditioning regimen. Weighted Kaplan–Meier analyses were used to estimate OS and RFS. Statistical analyses were performed using R version 4.4.0. Results: A total of 144 patients were included. Median age was 57 years (IQR 43–64), and 53% were male. At transplant, 61% of patients were in first complete remission (CR1) and 22% in second complete remission (CR2). By ELN 2022 risk stratification, 22% had favorable-, 28% intermediate-, and 50% adverse-risk disease. One hundred patients (69%) received anthracycline-based induction, 34 patients (23%) received HMA/VEN, and 10 patients (7%) received CPX-351. Induction strategy differed significantly by ELN risk category. Patients with favorable- and adverse-risk AML were more likely to receive anthracycline-based induction compared with those with intermediate-risk disease (94% and 70% vs 46%, respectively; p<0.01). CPX-351 was used almost exclusively in patients with adverse-risk AML. Patients receiving anthracycline-based induction were younger (median age 55 years) than those treated with HMA/VEN or CPX-351 (both median age 61 years; p=0.017). Median follow-up from transplant was 66 months (IQR 43.3–NR). After IPTW adjustment, there was no significant difference in OS across induction regimens. Median OS was 101 months (95% CI 69–NR) for anthracycline-based induction, 91 months (95% CI 73–NR) for HMA/VEN, and 20 months (95% CI 16–NR) for CPX-351 (weighted p=0.20). In contrast, the CPX-351 group demonstrated inferior RFS, with a median RFS of 11 months (95% CI 5–15), compared with not reached for anthracycline-based induction and 50 months (95% CI 6.6–NR) for HMA/VEN (weighted p=0.04). Conclusions: In this retrospective analysis, pre-transplant induction regimen was not associated with differences in overall survival after allo-HCT. Patients receiving CPX-351 had a higher risk of post-transplant relapse after adjustment for ELN risk and other confounders. These findings should be confirmed in prospective clinical trials.