A multicenter phase 2 clinical trial of low-dose subcutaneous decitabine in myelofibrosis

•The overall response rate for low-dose subcutaneous decitabine was 33% in this prospective clinical trial of 21 patients with myelofibrosis.•A high Lille score, high fetal hemoglobin, and decrease in circulating CD34+ cells were associated with response. [Display omitted] Myelofibrosis (MF) in the chronic phase is a challenging disease to treat, and conventional treatment options are geared toward symptom palliation. In this prospective, multicenter, phase 2 trial, 21 patients with MF (18 chronic phase, 2 accelerated phase, and 1 blast phase) were treated with a 10-day schedule of subcutaneous decitabine at 0.3 mg/kg per day. The overall response rate was 33% (95% confidence interval, 15-57), primarily manifested as an improvement in cytopenias. The median duration of response was 7 months (range, 3-44). A high International Prognostic Scoring System risk score, high baseline fetal hemoglobin level, and sustained decrease in circulating CD34+ cell counts were associated with response to decitabine. All patients experienced at least 1 grade 3/4 cytopenia. Nonhematologic toxicities were less frequent, with fatigue, anorexia, and hypocalcemia being the most common. Given the lack of effective therapies in MF with severe cytopenias, this study supports further investigation into the use of hypomethylating agents as single agents or in combination therapies. This trial was registered at www.ClinicalTrials.gov as #NCT00095784.