Study Compares Safety Profile of 2 JAK Inhibitors in Patients With Myelofibrosis

The JAK inhibitor (JAKi) momelotinib appears to have a superior safety profile compared with fedratinib in patients with myelofibrosis (MF), according to a study presented at the 2023 American Society of Clinical Oncology Annual Meeting.

Momelotinib has demonstrated consistent benefit in improving anemia, symptoms, and spleen volume in patients with MF. While previous trials have compared momelotinib with ruxolitinib, with momelotinib displaying a better toxicity profile, less is known about how momelotinib compares with other JAKis, such as fedratinib.

In this study, lead author Lucia Masarova and colleagues performed a matching-adjusted indirect comparison of outcomes from phase 2 and/or 3 momelotinib and fedratinib trials. They focused on adverse events (AEs) occurring in >10% of a treatment arm over 24 weeks. The primary outcomes of this study were defined as grade 3/4 anemia and thrombocytopenia.

Following analysis, the researchers observed that the risk of any or grade 3/4 anemia, diarrhea, nausea, and serious AEs leading to dose reductions were statistically less likely with momelotinib versus fedratinib in both populations. Moreover, the analysis showed that the risk of any or grade 3/4 thrombocytopenia was also less likely with momelotinib compared with fedratinib, significantly so in JAKi-naive patients. The researchers noted that “[momelotinib] showed a favorable safety profile versus [fedratinib] in both JAKi-naive and experienced patients, including a significantly lower risk of key hematologic AEs, diarrhea, and nausea over 24 weeks.”

Source: Masarova L, Verstovsek S, Palandri F, et al. Indirect treatment comparison (ITC) of momelotinib (MMB) vs fedratinib (FED) safety in patients (pts) with myelofibrosis (MF). Abstract #7065. Published for the 2023 ASCO Annual Meeting; June 2-6, 2023; Chicago, Illinois.