Momelotinib Lowers Transfusion Requirements in Patients With Transfusion‑Dependent Myelofibrosis

Transfusion-dependent (TD) patients with myelofibrosis treated with momelotinib, a small molecule inhibitor of Janus kinase (JAK)1/JAK2/activin A receptor type 1, experienced a decline or stabilization of red blood cell (RBC) transfusion requirements, potentially positively impacting this patient populations’ quality of life.

Patients with myelofibrosis, a rare blood cancer, are commonly managed with RBC transfusions, which can negatively impact survival and quality of life.

Harrison et al. set out to “report novel analyses in transfusion-dependent patients with myelofibrosis enrolled in a phase II study of momelotinib and to fully characterize the treatment effect on overall transfusion burden.”

In the study, the researchers quantified the time-dependent transfusion burden by the number of transfused RBC units during the pretreatment and 24-week treatment periods. They assigned patients enrolled in a phase II study into baseline- and treatment-period categories based on the intensity of RBC units every 28 days: 0, >0 to 1, >1 to 2, >2 to 3, >3 to 4, and >4.

The researchers considered patients eligible for the analysis if they had a prestudy average of ≥2 RBC units every 28 days during the 56-day pretreatment period. At baseline, most eligible patients were TD (40/41) and JAK inhibitor-naïve (36/41).

The mean RBC transfusion requirement was 3.2 units every 28 days before momelotinib initiation. The mean transfusion requirement after momelotinib initiation was reduced to 1.7 units every 28 days, with 85% of patients (35/41) achieving a numeric reduction in transfusions.

Additionally, 90% of patients (37/41) showed improved (26/41) or stable (11/41) transfusion intensity. A total of nine patients (22%) became transfusion free for the entire treatment period, while transfusion requirements increased in 10% of patients (4/41).

“These data demonstrate that nearly all TD patients treated with momelotinib (90%) experienced a decline or stabilization of transfusion requirements and further support the differentiated activity of momelotinib in providing anemia benefit,” the researchers concluded.

Reference

Harrison C, Mesa R, Talpaz M, et al. Reduction in red blood cell transfusion burden: a novel longitudinal time‑dependent analysis in patients with transfusion‑dependent myelofibrosis treated with momelotinib. Clin Lymphoma Myeloma Leuk. 2023;23(supp 1):S383-S384