Early use of recombinant IFN‑alfa in patients with PV

A review, detailing evidence for the early use of recombinant interferon-alfa (rIFN‑alfa) in patients with polycythemia vera (PV) based on clinical efficacy and safety data, was published in Leukemia by Silver and Hasselbalch.  

Key data: The regularly employed phlebotomy-only (PHLEB‑O) approach to PV management allows clonal expansion, increased risk of major thrombosis, and the development of myelofibrosis (MF) in low-risk patients. Treatment with rIFN‑alfa has been shown to reduce JAK2V617F variant allele frequency (VAF), reducing the risk of thromboembolic events and inflammation-associated comorbidities. Studies suggest that the ability of rIFN‑alfa to induce a complete hematologic response (CHR) is greater in the early stages of PV, before the development of MF. The toxicity profile of rIFN‑alfa does not differ greatly from that of hydroxyurea (HU), but it has a well-documented safety profile during conception, pregnancy, and lactation. Long-term treatment with rIFN‑alfa enables sustained normal blood counts and low JAK2V617F VAF in a subset of patients with PV. By improving defective tumor immune surveillance, rIFN‑alfa may also reduce the risk of secondary malignancies and improve overall survival (OS).  

Key learning: Initial early rIFN‑alfa therapy may reduce thrombotic risk, limit clonal evolution, and induce MRD in patients with PV, and may be a suitable option for pregnant or lactating patients. Further studies are warranted to characterize patients who are able to achieve long-term MRD.