Momelotinib is the fourth JAK inhibitor to be approved by the agency for myelofibrosis but the only one indicated for patients with hemoglobin levels below 10 g/dL.
It's an important development because, while JAK inhibitors are standard treatment for myelofibrosis, those previously approved for the uncommon blood cancer can cause cytopenia, particularly anemia, which, ironically, is also a hallmark of myelofibrosis itself.
This issue makes using JAK inhibitors for myelofibrosis challenging, according to Anthony Hunter, MD, a myeloid malignancies specialist at Emory University School of Medicine, Atlanta, Georgia, who spoke on the topic recently at the Society of Hematologic Oncology annual meeting in Houston. "Momelotinib is an important emerging agent for these more anemic patients." Momelotinib has a spleen response comparable to ruxolitinib — the first JAK inhibitor approved for myelofibrosis in the United States — and significantly higher rates of transfusion independence, although lower rates of symptom control, he said.
In GSK's press release, hematologist/oncologist Ruben Mesa, MD, executive director of Atrium Health Wake Forest Baptist Comprehensive Cancer Center in Winston-Salem, North Carolina, said that "with momelotinib, we have the potential to establish a new standard of care for myelofibrosis patients with anemia."
Momelotinib's specific indication is for "the treatment of intermediate or high-risk myelofibrosis, including primary myelofibrosis or secondary myelofibrosis (post-polycythemia vera and post-essential thrombocythemia), in adults with anemia."
The once-daily oral medication was approved based on two trials. One trial, MOMENTUM, showed statistically significant response with respect to constitutional symptoms, splenic response, and transfusion independence in anemic patients treated with momelotinib versus danazol.
An anemic subset of the SIMPLIFY-1 trial showed comparable spleen volume reduction versus ruxolitinib but a numerically lower symptom response rate.
The most common momelotinib adverse reactions in trials were thrombocytopenia, hemorrhage, bacterial infection, fatigue, dizziness, diarrhea, and nausea.
M. Alexander Otto is a physician assistant with a master's degree in medical science and a journalism degree from Newhouse. He is an award-winning medical journalist who worked for several major news outlets before joining Medscape and is also an MIT Knight Science Journalism fellow. Email: email@example.com
Lead image: Dreamstime
Cite this: FDA Approves JAK inhibitor Momelotinib for Myelofibrosis With Anemia - Medscape - Sep 15, 2023.