Objective To investigate the clinical characteristics of 35 elderly patients with acute myeloid leukemia (AML) who were newly treated and intolerant to intensive chemotherapy and evaluate treatment efficacy and safety of venetoclax combined with azacytidine (VEN+AZA). Methods Between February 2021 and March 2022, 35 AML elderly patients who were intolerant to intensive therapy were enrolled in the study. They received VEN+AZA induction therapy. The disease characteristics, VEN+AZA induced remission and treatment safety were retrospectively analyzed and reported. Results The median age of enrolled patients was 68 year old, and there were 9 cases diagnosed with secondary AML. All patients completed bone marrow cytogenetic and molecular biology evaluation and were stratified by European LeukemiaNet (ELN) genetic risk classification. Thirty-five patients were classified as low risk group (10 of 35 cases), intermediate risk group (12 of 35 cases) and high risk group (13 of 35 cases). Common genetic mutations included DNA methyltransferase 3A (DNMT3A) (n=11), isocitrate dehydrogenase (IDH) 1/2 (n=11), ten-eleven translocation 2 (TET2) (n=9), NPM1 (n=8) and Fms-related tyrosine kinase 3-internal tandem duplication (FLT3-ITD) (n=6). The overall complete remission (CR) rate of treatment was 65.7% (n=23), and the CR rate of patients with mutation of NPM1, FLT3-ITD, IDH1/2 were 87.5%, 66.7% and 72.7%, respectively. The total negative rate of minimal residual disease (MRD) among CR patients was 73.9%, the median follow-up time was 10.1 months and median event-free survival (EFS) was 11.3 months. Among remission patients, MRD-negative patients had longer EFS and overall survival than MRD-positive patients（P<0.05）. The early mortality rate was 5.7%. The most common adverse reaction during treatment was hematological toxicity (treatment-induced grade 3-4 neutropenia 31.4%, grade 3-4 thrombocytopenia 25.7%, febrile neutropenia 48.6%) and pulmonary infection (17.1%). Conclusions Our results showed that VEN+AZA has a higher overall response rate in newly treatment elderly AML who were intolerant to intensive chemotherapy, which was similar with the clinical trial results. NPM1 mutation might indicate higher CR rate. The EFS and OS of MRD-negative patients were longer than those of MRD-positive patients, and the risk of death was reduced. In summary, VEN+AZA regime was currently one of the most promising strategies for newly treated elderly AML who couldn’t tolerate intensive chemotherapy.
