DP024 | PROGNOSTIC RELEVANCE OF COMPLETE HEMATOLOGICAL RESPONSE IN ACUTE MYELOID LEUKEMIA TREATED WITH NON INTENSIVE REGIMENS, A MULTICENTRIC, RETROSPECTIVE, OBSERVATIONAL STUDY

Introduction: Better overall survival (OS) is observed for patients affected by acute myeloid leukemia (AML) treated with intensive regimens and achieving complete remission (CR) compared to CRp (CR with incomplete or partial hematological recovery and morphologic leukemia-free state). Data addressing this association in non-intensive treatments settings are lacking. Methods: In this observational, retrospective, multi-center study, AML patients who received at least one cycle of first-line hypomethylating agents and Venetoclax were included. Primary endpoint: OS stratified by CR vs CRp. Secondary endpoints: disease-free survival (DFS) stratified by CR vs CRp and evaluation of variables associated with treatment response and survival. Data from 206 patients, treated in 9 centers between 01/06/2019 and 01/06/2024, were analyzed. Results: The median age at diagnosis was 76 years (61-90). Most patients (87%) were deemed unfit for intensive therapy, 25 patients (12%) fit and 2 patients (1%) frail. High-risk disease (ELN 2022) was identified in 121 pts (59%). The overall response rate (ORR) was 60%, with 60 patients (29%) achieving CR. Median follow-up was 25.6 months, median OS was 29 months (95% CI, 16 months–NR) for patients achieving CR and only 16 months (12–20 months; p=0.02) in case of CRp. Factors negatively affecting OS in univariate analysis were: CRp (HR 1.75, 95% CI 1.08–2.84, p=0.02), complex karyotype (HR 3.05, 1.53–6.09, p=0.002), TP53 mutations (HR 4.21, 1.63–10.9, p=0.003), and high risk disease (HR 2.38, 1.15-4.9, p=0.02). Conversely, positive association with OS was found with higher hemoglobin levels (HR 0.84, 0.74–0.95, p=0.008) and NPM1 mutations at diagnosis (HR 0.48, 0.25–0.9, p=0.02). Similarly, median DFS was significantly longer in CR compared to CRp patients (17 months [95% CI, 11 months–NR] vs 6.5 months [95% CI, 5.4–13 months]; p=0.02). Variables influencing DFS were similar to those affecting OS. The leading cause of death was disease progression (57%, 82 pts), followed by infections (35%, 51 pts), and other causes (8%, 11 pts), without differences in distribution between response groups. Achieving CR as best response was significantly associated with improved OS and DFS in NIT patients with AML, the advantage was confirmed by multivariate analysis. The longer DFS observed in CR highlights the importance of deeper remission even in a non-curative setting, particularly given the similar causes of death across response groups.