Ropeginterferon Alfa-2b Effective at Treating Prefibrotic Primary Myelofibrosis

Ropeginterferon alfa-2b is an effective treatment for patients with primary myelofibrosis (MF) in the pre-/early fibrotic stage (pre-PMF), according to a study that will be presented at the 65th ASH Annual Meeting & Exposition, which is taking place December 9-12 in San Diego, California.

P1101MF is an ongoing, multicenter, phase 2 study. Researchers assessed 37 men and 29 women (median age of the full patient population, 59 years) with confirmed pre-PMF, overt PMF, post-polycythemia vera MF, or post-essential thrombocythemia MF; DIPSS low/intermediate-1-risk disease; and the need for cytoreduction.

The primary end point of interest was defined as responses to ropeginterferon alfa-2b in hemoglobin (Hb; from 10 g/dL to upper reference range), white blood cell (WBC; < 10 × 10⁹/L), and platelet (≤ 400 × 10⁹/L) at both 24 and 48 weeks. Secondary end points included adverse events (AEs) and changes in mutant allele frequencies (MAF).

According to the findings, responses in Hb, WBC, and platelet were 75%, 82%, and 74%, respectively, at 24 weeks and 82%, 80%, and 71%, respectively, at 48 weeks. The researchers also observed a reduction of MAF at 24 and 48 weeks for JAK2 V617F in 50% of men and 79% of women.

Five treatment discontinuations and no cases of disease progression (pre-PMF to overt PMF) were observed. Nonhematological AEs included transaminitis and malaise, while the most common hematological AE was anemia.

“[Ropeginterferon] was well-tolerated, effective in cytoreduction, and induced molecular and morphologic responses in patients with pre-PMF and low/intermediate-1-risk MF,” the researchers concluded.

Reference

Gill H, Au L, Leung G, et al. Ropeginterferon Alfa-2b for Pre-Fibrotic Primary Myelofibrosis and DIPSS Low/Intermediate-1 Risk Myelofibrosis: Durable Responses and Evidence of Disease Modification. Abstract #4562. Presented at the 65th ASH Annual Meeting & Exposition; December 9-12, 2023; San Diego, California.