Recombinant interferon alfa in BCR/ABL-negative chronic myeloproliferative neoplasms.

The treatment landscape for BCR/ABL-negative myeloproliferative neoplasms (MPNs), driven by JAK2, CALR, and MPL mutations, has evolved significantly over the last decade. Recent regulatory approvals in polycythemia vera (PV) include the JAK inhibitor ruxolitinib, and more recently, a novel recombinant interferon alfa-2 (IFN-α) therapeutic agent. Many clinical trials have documented the safety and efficacy of IFN-α therapy in PV and essential thrombocythemia, the classical BCR/ABL-negative MPNs. Used off-label for more than 30 years as a cytoreductive agent, IFN-α therapy promotes significant clinical, hematologic, and molecular responses. In some IFN-α-treated patients, partial or complete reduction of the mutant JAK2 allele burden may lead to a durable measurable residual disease state, owing to the ability of long-term IFN-α therapy to selectively deplete mutant JAK2-harboring hematopoietic stem cells. Pegylated IFN-α forms were developed to improve the drug stability and tolerability of first-generation IFN-α therapeutics. More recently, a novel pegylated IFN-α, ropeginterferon alfa-2b, received approval for PV by the European Medicines Agency and the US Food and Drug Administration in 2019 and 2021, respectively. This article reviews the clinical research and recent advances that led to the first regulatory approval of IFN-α in a BCR/ABL-negative MPN and its future promise as a disease-modifying therapeutic agent.