Ropeginterferon alfa-2b, a novel IFNα-2b, induces high response rates with low toxicity in patients with polycythemia vera

Blood. 2015 Oct 8;126(15):1762-9. doi: 10.1182/blood-2015-04-637280. Epub 2015 Aug 10.


In this prospective, open-label, multicenter phase 1/2 dose escalation study, we used a next-generation, mono-pegylated interferon (IFN) α-2b isoform, ropeginterferon alfa-2b. The unique feature of ropeginterferon alfa-2b is a longer elimination half-life, which allows administration every 2 weeks. We present data from 51 polycythemia vera patients. The main goal was to define the maximum tolerated dose and to assess safety and efficacy. A dose range of 50 to 540 µg was tested without the appearance of dose-limiting toxicities. All drug-related adverse events were known toxicities associated with IFN-α. The cumulative overall response rate was 90%, comprising complete response in 47% and partial response in 43% of patients; the best individual molecular response level was a complete response in 21% of patients and partial response in 47%. Notably, we did not observe any correlation between the dose level and the response rate or response duration, suggesting that already low levels of ropeginterferon alfa-2b are sufficient to induce significant hematologic and molecular responses. These data suggest promising efficacy and safety of ropeginterferon alfa-2b and support the development of the drug in a randomized phase 3 clinical trial. The study was disclosed at as #NCT01193699 before including the first patient.

Publication types

  • Clinical Trial, Phase I
  • Clinical Trial, Phase II
  • Multicenter Study

MeSH terms

  • Adult
  • Aged
  • Aged, 80 and over
  • Female
  • Follow-Up Studies
  • Half-Life
  • Humans
  • Interferon alpha-2
  • Interferon-alpha / therapeutic use*
  • Male
  • Maximum Tolerated Dose
  • Middle Aged
  • Neoplasm Staging
  • Polycythemia Vera / drug therapy*
  • Polycythemia Vera / mortality
  • Polycythemia Vera / pathology
  • Polyethylene Glycols / chemistry*
  • Prognosis
  • Recombinant Proteins / therapeutic use*
  • Remission Induction
  • Survival Rate


  • Interferon alpha-2
  • Interferon-alpha
  • Recombinant Proteins
  • Polyethylene Glycols

Associated data