Myelofibrosis is often characterized by anemia, spleen enlargement, fatigue, night sweats and bone pain. These symptoms can be extremely burdensome. New medications are needed to address these issues in order to provide a better quality of life for patients.

JAK Inhibitors for Myelofibrosis

Myelofibrosis side effects are caused by a dysregulation of the Janus kinase (JAK) pathway. This leads to the abnormal growth of red and white blood cells and platelets, as well as an overproduction of the body’s inflammatory response. Currently, there are three JAK inhibitors that are commonly used to treat myelofibrosis: ruxolitinib, fedratinib and pacritinib.

“Safe and effective treatment is needed for patients with myelofibrosis who are anemic or are no longer candidates for receiving currently approved JAK inhibitors.” 

Monelotinib: A Safe And Effective Medication

Momelotinib is a first-in-class oral inhibitor that has been tested on previously treated patients with intermediate/high-risk myelofibrosis. In studies, this medication has demonstrated strong clinical activity in treating the most difficult symptoms of this disease. This information was collected from 3 different studies (MOMENTUM, SIMPLIFY-1, and SIMPLIFY-2).

Study Statistics

Across these studies, 725 myelofibrosis patients received momelotnib: 

• 12% of patients remained on this therapy for more than 5 years
• 20% of patients experienced diarrhea
• Anemia occurred in 25% of patients
• Overall, 50.6% of patients received more than 48 months of treatment
• Infections occurred as expected, but were mostly low-grade
• Long term safety and survival was common

The median dose administered was 195 mg a day. Overall survival probabilities were 76.5% at 2 years, 59.6% at 4 years and 51.1% at 6 years. Most side effects did not worsen with continued momelotinib treatment.

Conclusion

“Momelotinib is the first inhibitor of Janus kinase 1 (JAK1) and JAK2 shown to also inhibit activin A receptor type 1 (ACVR1), a key regulator of iron homeostasis (balancing iron utilization and storage), and has demonstrated improvements in splenomegaly (enlarged spleen), constitutional symptoms (fatigue, anorexia and involuntary weight loss), and anemia in myelofibrosis.” Momelotinib, which is approved in the United States, is the first and only treatment indicated for myelofibrosis patients with anemia.