Momelotinib in Combination With Hypomethylating Agent for Chronic Phase Myelodysplastic Syndromes/Myeloproliferative Overlap Neoplasms and Chronic Neutrophilic Leukemia

The investigators will randomize the first 10 patients to receive 200 mg momelotinib (MMB) monotherapy for first 3 cycles with addition of HMA starting cycle 4 (Arm A, n=5) versus starting with MMB-HMA combination both starting in cycle 1 (Arm B, n=5). The regimen used for the next 8 patients (Arm C- expansion) will be determined after an interim analysis of Arms A and B at week 12 after the first 10 participants have been randomized.

75 mg/m2, days 1-5 in a 28-day cycle

20mg/m2, days 1-5 in a 28-day cycle