Natural history of chronic myelomonocytic leukemia treated with hypomethylating agents

Abstract

Hypomethylating agents (HMA) are the most commonly used therapeutic intervention in chronic myelomonocytic leukemia (CMML). Due to the lack of CMML-specific clinical trials, the impact of these agents in the natural history of CMML is not fully understood. We present the largest retrospective series of CMML (n = 151) treated with HMA. Mean age at diagnosis was 69 years (range 50-88). According to the CMML-specific prognostic scoring system (CPSS): 17 (15%) were low-risk, 45 (39%) intermediate-1 risk, 42 (36%) intermediate-2, and 12 (10%) high-risk. 35 (23%) patients received single agent azacitidine, 73 (48%) single agent decitabine, and 43 (29%) combinations. With a median follow-up of 17 months, overall response rate (ORR) was 75%, with 41% achieving complete response (CR). Median overall survival (OS) was 24 months (95%CI: 20-28) and event-free survival 14 months (95%CI: 11-17). By multivariate analysis, age < 70 years, higher levels of hemoglobin, absence of blast in peripheral blood and lower CPSS cytogenetic risk predicted for better OS. CR was significantly higher in those patients treated with decitabine (58.3%) when compared with azacitidine (20.6%) (P