A phase 2 study of ruxolitinib in combination with azacitidine in patients with myelofibrosis.

Ruxolitinib (RUX)-based combinations may provide benefit for patients with myelofibrosis (MF). In this open-label, nonrandomized, prospective phase 2 study, patients with MF initially received RUX twice per day continuously in 28-day cycles for the first 3 cycles. Azacitidine (AZA) 25 mg/m2 (days 1-5) was added starting with cycle 4 and could be subsequently increased to 75 mg/m2 (days 1-5). Forty-six patients were enrolled with a median follow-up of 28 months (range, 4-50+ months). An International Working Group for Myelofibrosis Research and Treatment (IWG-MRT) response was achieved in 33 patients (72%), with a median time to response of 1.8 months (range, 0.7-19.0 months). One-fourth (7 of 33) of the IWG-MRT responses occurred after the addition of AZA. A reduction of >50% in palpable spleen length at 24 weeks and at any time on the study was achieved in 62% and 71% of the evaluable patients, respectively. Among patients who achieved a >50% reduction in spleen length at 24 weeks, 95% had maintained it at 48 weeks. Notably, improvements in bone marrow reticulin fibrosis grade occurred in 57% of the patients at 24 months. Treatment discontinuations as a result of drug-related toxicities occurred in 4 patients (9%), all as a result of cytopenias. New onset grade 3 to 4 anemia and thrombocytopenia occurred in 35% and 26% of patients, respectively. RUX and AZA were safe, with encouraging spleen response rates and improvement in bone marrow fibrosis in patients with MF. This trial was registered at www.clinicaltrials.gov as #NCT01787487.

A phase II trial of ruxolitinib in combination with azacytidine in myelodysplastic syndrome/myeloproliferative neoplasms.

Ruxolitinib and azacytidine target distinct disease manifestations of myelodysplastic syndrome/myeloproliferative neoplasms (MDS/MPNs). Patients with MDS/MPNs initially received ruxolitinib BID (doses based on platelets count), continuously in 28-day cycles for the first 3 cycles. Azacytidine 25 mg/m2 (Day 1-5) intravenously or subcutaneously was recommended to be added to each cycle starting cycle 4 and could be increased to 75 mg/m2 (Days 1-5) for disease control. Azacytidine could be started earlier than cycle 4 and/or at higher dose in patients with rapidly proliferative disease or with elevated blasts. Thirty-five patients were treated (MDS/MPN-U, n =14; CMML, n =17; aCML, n =4), with a median follow-up of 15.2 months (range, 1.0-41.5). All patients were evaluable by the 2015 international consortium proposal of response criteria for MDS/MPNs (ICP MDS/MPN) and 20 (57%) responded. Nine patients (45%) responded after the addition of azacytidine. A greater than 50% reduction in palpable splenomegaly at 24 weeks was noted in 9/14 (64%) patients. Responders more frequently were JAK2-mutated (P = .02) and had splenomegaly (P = .03) compared to nonresponders. New onset grade 3/4 anemia and thrombocytopenia occurred in 18 (51%) and 19 (54%) patients, respectively, but required therapy discontinuation in only 1 (3%) patient. Patients with MDS/MPN-U had better median survival compared to CMML and aCML (26.5 vs 15.1 vs 8 months; P = .034). The combination of ruxolitinib and azacytidine was well-tolerated with an ICP MDS/MPN-response rate of 57% in patients with MDS/MPNs. The survival benefit was most prominent in patients with MDS/MPN-U.