Outcome of patients with high risk Myelodysplastic Syndrome (MDS) and advanced Chronic Myelomonocytic Leukemia (CMML) treated with decitabine after azacitidine failure.

Outcome of patients with high risk MDS and CMML who failed treatment with azacitidine remains poor with a median survival of 6 months, without established therapy available except allogeneic hematopoietic stem cell transplantation. The objective of our study was to evaluate efficacy of decitabine after azacitidine failure in a relatively large patient cohort based on conflicting results with 0-28% response rates (RR) in this setting in small patient series. Thirty-six consecutive high risk MDS and CMML patients who received decitabine after azacitidine failure were retrospectively reviewed. Response was based on IWG 2006 criteria for MDS and CMML with WBC<13G/l and also included for proliferative CMML the evolution of WBC, splenomegaly (SMG) and extramedullary disease (EMD). Patients received a median number of 3 (range 1-27) cycles of decitabine and 12 patients received at least 6 cycles. Seven (19.4%) patients were responders including 3 marrow CR (mCR), 2 stable disease (SD) with HI-E, 1 SD with HI-N and HI-P and 1 SD with HI-N. In a CMML patient with SD, specific skin lesions resolved with decitabine. Responses were generally short lived (2-5 months) except 1 responder currently ongoing with +11 months follow up. Two non-responders had prolonged SD (without HI) of 21 and 27 months duration respectively. Median OS from onset of decitabine was 7.3 months, without significant difference between responders and non-responders. Treatment with decitabine after azacitidine failure yielded modest ORR (19.4%) with short response duration and poor OS. Thus, use of decitabine in such patients who failed or progressed after azacitidine cannot be recommended, underscoring the need for novel strategies in this setting.