Published April 3, 2025
Ruben Mesa, Abdulraheem Yacoub, Tsewang Tashi, Wanxing Chai-Ho, Chang Ho Yoon & John Mascarenhas
Dear Editor,
We write to highlight the critical shortage of peginterferon alfa-2a (peg-IFN), as confirmed by the FDA [1], which has impacted many patients with myeloproliferative neoplasms (MPNs). Those relying on peg-IFN for long-term disease control in polycythemia vera (PV), essential thrombocythemia (ET), and myelofibrosis (MF) face supply disruptions that can compromise disease stability and overall health.
Ropeginterferon alfa-2b (ropeg-IFN) is a viable alternative. It is the only FDA-approved interferon for PV and is considered first-line therapy as per the January 2025 NCCN Guidelines [2]. Though not yet approved for ET or MF, off-label use may be justified in situations where no other options exist. Our group has accumulated experience in transitioning patients from peg-IFN to ropeg-IFN due to historic insurance issues and clinical trial participation, allowing us to propose practical strategies for safe conversion.
A best-practice approach to dose equivalence, based on collective experience and real-world data, is pragmatic given that no formal head-to-head dosing trials exist.[3,4,5] For patients previously on peg-IFN 135–180 µg weekly, we typically initiate ropeg-IFN at 250–350 µg every two weeks, adjusting for hematologic response and tolerability. Those on lower peg-IFN doses (45–90 µg/week) may begin on 200–250 µg every two weeks. If disease control proves challenging, starting at, e.g., 350 µg with possible escalation to 500 µg every two weeks can be considered. Whichever starting dose is chosen, close monitoring and dose adjustments are essential to maintain efficacy while minimizing toxicity.