FDA grants fast track designation to momelotinib for myelofibrosis

The FDA granted fast track designation to momelotinib for the treatment of patients with intermediate- or high-risk myelofibrosis who previously received a JAK inhibitor.

Momelotinib (Sierra Oncology Inc.) is a selective and orally bioavailable JAK1, JAK2 and ACVR1 inhibitor.

Sierra Oncology intends to launch the randomized phase 3 MOMENTUM trial to evaluate the activity of momelotinib for symptomatic, anemic patients with primary myelofibrosis, post-polycythemia vera myelofibrosis or post-essential thrombocythemia myelofibrosis previously treated with JAK inhibitor therapy.

The double-blind study, expected to begin in the fourth quarter of this year, will be designed to enroll 180 patients. Researchers will assign them 2:1 to momelotinib or danazol, a synthetic steroid used to ameliorate anemia among individuals with myelofibrosis. After 24 weeks, patients assigned danazol will be allowed to cross over to momelotinib.

Total symptom score response rate at week 24 will serve as the primary endpoint. Secondary and exploratory endpoints will include transfusion independence and splenic response rate at week 24, duration of total symptom score response to week 48, anemia benefit, and patient-reported outcome measures of fatigue and physical function.

“Fast track designation for momelotinib highlights the serious and significant unmet needs of patients with myelofibrosis who have previously received a JAK inhibitor,” Barbara Klencke, MD, chief development officer at Sierra Oncology, said in a company-issued press release. “These patients typically suffer from uncontrolled constitutional symptoms, progressively worsening anemia often resulting in transfusion dependency, and enlarged spleens. Fast track also recognizes the absence of FDA-approved treatments for these patients and that momelotinib has the potential to address their unmet needs.”