Sierra Oncology has received the US Food and Drug Administration’s (FDA) fast track designation for its investigational drug momelotinib.

Indicated to treat intermediate / high-risk myelofibrosis, the therapeutic is designed for patients that have previously been treated with a Janus kinase (JAK) inhibitor.

Momelotinib is a potent and selective inhibitor of JAK1, JAK2 and Activin A Receptor Type 1 (ACVR1). Since 2009, more than 1,200 individuals have been treated with momelotinib across various clinical studies.

The company noted that the therapeutic offers symptom improvements and multiple anaemia benefits such as elimination or decrease in the need for frequent blood transfusions and comparable spleen control to ruxolitinib.

Sierra Oncology chief development officer Dr Barbara Klencke said: “Fast-track designation for momelotinib highlights the serious and significant unmet needs of patients with myelofibrosis who have previously received a JAK inhibitor.

“These patients typically suffer from uncontrolled constitutional symptoms, progressively worsening anaemia often resulting in transfusion dependency, and enlarged spleens.”

The company is planning to launch a Phase III trial to assess momelotinib in symptomatic, post-polycythemia vera (PV), post essential thrombocythemia (ET) or anaemic primary (PMF) myelofibrosis patients that previously received JAK inhibitor therapy.

Dubbed MOMENTUM, the randomised, double-blind trial will compare the therapeutic to Danazol in a total of 180 participants over 24 weeks.

The primary endpoint of the study is the Total Symptom Score (TSS) response rate at week 24, while secondary and exploratory endpoints include transfusion Independence (TI) rate and aplenic response rate (SRR) at week 24.

In addition, the trial will monitor the duration of TSS response to week 48, other anaemia benefit measures, including transfusion dependence response rate and patient-reported outcomes for fatigue and physical function.