FDA Approves Momelotinib for Patients With Anemia and Myelofibrosis

The US Food and Drug Administration (FDA) announced on September 15, 2023, their approval of momelotinib (Ojjaara) for patients with myelofibrosis (MF) and anemia. In the US, about 25,000 patients have been diagnosed with MF, and one of the rare blood cancer’s common symptoms is progressive anemia.

Momelotinib is an oral, once-a-day treatment intended for adult patients with intermediate- or high-risk MF and anemia, and it is the only medication approved for newly diagnosed and previously treated patients. It works by inhibiting  Janus Kinase (JAK1)/JAK2 and activin A receptor type 1 (ACVR1). The inhibition of ACVR1 helps reduce levels of a key contributor to anemia, hepcidin.

According to a press release from GSK, FDA approval for momelotinib was based off data from two key studies: MOMENTUM and SIMPLIFY-1 (GSK. September 15, 2023. https://www.gsk.com/en-gb/media/press-releases/ojjaara-momelotinib-approved-in-the-us-as-the-first-and-only-treatment-indicated-for-myelofibrosis-patients-with-anaemia/).

The MOMENTUM study was a global, phase III, multicenter, double-blind, randomized clinical trial that compared momelotinib to danazol in patients with MF who were symptomatic, anemic, and previously treated with a JAK inhibitor. The goal for this study was to assess the efficacy and safety of momelotinib in its ability to lessen disease symptoms, blood transfusions, and splenomegaly. The study met all of its primary and key secondary endpoints, and momelotinib showed a statistically significant improvement in symptoms when compared to danazol.

The SIMPLIFY-1 study was a phase III, multicenter, double-blind, randomized clinical trial that compared the safety and effectiveness of momelotinib to ruxolitinib in patients with MF who had not received prior JAK inhibitor treatment. The results were based on spleen volume response in a subset of patients within the trial who had anemia (GSK. Ojjaara Prescribing Information. Last updated September 20, 2023. https://gskpro.com/content/dam/global/hcpportal/en_US/Prescribing_Information/Ojjaara/pdf/OJJAARA-PI-PIL.PDF). 

The most common adverse reactions, seen in 20% of patients, were hemorrhage, thrombocytopenia, fatigue, bacterial infection, dizziness, diarrhea, and nausea. It is also recommended that physicians monitor patients receiving momelotinib for infection and hepatitis B (GSK. Ojjaara Prescribing Information. Last updated September 20, 2023. https://gskpro.com/content/dam/global/hcpportal/en_US/Prescribing_Information/Ojjaara/pdf/OJJAARA-PI-PIL.PDF). 

“With momelotinib we have the potential to establish a new standard of care for myelofibrosis patients with anemia. Addressing key manifestations of myelofibrosis, including anemia, constitutional symptoms and splenomegaly, makes a significant difference in the treatment regimen for these patients who have limited options to address these aspects of the disease,” said Ruben A. Mesa, MD, president and executive director of Atrium Health Levine Cancer Center, Charlotte, North Carolina.