How it is administered

Momelotinib is taken by mouth as a tablet. The recommended dose is 200 mg once daily, with or without food. Tablets should be swallowed whole and not cut, crushed, or chewed. If you miss a dose, take your next scheduled dose the following day. Dose adjustments may be needed for patients with severe liver problems or if certain side effects occur.

How it works

Momelotinib works by blocking specific enzymes called Janus Kinases (JAK1 and JAK2) and a protein called ACVR1. These enzymes and proteins are involved in the signaling pathways that control blood cell production and immune function. In myelofibrosis, these pathways are often overactive, leading to abnormal blood cell growth, inflammation, and symptoms like anemia and an enlarged spleen.

By inhibiting JAK1, JAK2, and ACVR1, momelotinib helps reduce abnormal cell signaling, which can decrease inflammation and improve blood cell counts. It also lowers the production of hepcidin, a hormone that restricts iron availability, thereby increasing red blood cell production and helping with anemia. This dual action makes momelotinib especially useful for people with myelofibrosis who have anemia.

Who Should take it

Momelotinib is used for adults with intermediate or high-risk myelofibrosis, including primary myelofibrosis or myelofibrosis that develops after other blood disorders like polycythemia vera or essential thrombocythemia, especially in those who have anemia.

It is suitable for patients who have symptoms such as fatigue, enlarged spleen, or require frequent blood transfusions due to low red blood cell counts. Momelotinib can be used in people who have not previously received a JAK inhibitor, as well as those who have already tried other JAK inhibitors.

Who should not take it

There are no absolute contraindications listed for momelotinib, but it should not be started in people with active infections. Caution is needed in patients with severe liver problems, low platelet or neutrophil counts, or a history of severe skin reactions. Pregnant women should only use momelotinib if the benefits outweigh the risks, as animal studies suggest potential harm to the fetus. Breastfeeding is not recommended during treatment and for at least one week after the last dose.

Patients with chronic hepatitis B should be carefully monitored, and those with a history of cardiovascular disease, blood clots, or certain cancers should discuss the risks and benefits with their healthcare provider.

Commonly used with

Momelotinib is often used alone for myelofibrosis, but it may be given after other JAK inhibitors such as ruxolitinib if those are not effective or cause side effects. It is not typically combined with other myelofibrosis treatments, but your doctor may manage other conditions or symptoms with additional medications as needed.

Commonly tested with

In clinical trials, momelotinib has been compared to danazol and ruxolitinib in patients with myelofibrosis. It is not commonly tested in combination with other myelofibrosis medications, but may be studied alongside supportive therapies such as blood transfusions or treatments for anemia.