# Ropeginterferon alfa-2b

Source: https://onco.cc/drugs/ropeginterferon-alfa-2b/  
OnCo record `ropeginterferon-alfa-2b` (Treatment). Data CC BY-NC 4.0, attribute "Data from OnCo (onco.cc)"; commercial use needs a licence.

## TL;DR

Ropeginterferon alfa-2b is a long-acting interferon for polycythaemia vera that, unlike hydroxyurea, can shrink the mutant clone over years.

## Summary

Ropeginterferon alfa-2b is a mono-pegylated, long-acting interferon alfa given every two weeks. Type I interferon signalling preferentially suppresses the JAK2-mutant clone in polycythaemia vera, with antiproliferative and immunomodulatory effects that hydroxyurea does not share. In PROUD-PV and its CONTINUATION-PV extension, complete haematological response and JAK2 allele-burden reduction were superior to hydroxyurea by 3 to 6 years, and Low-PV showed benefit in low-risk patients who would otherwise receive phlebotomy alone. It was the first interferon approved specifically for PV, in the EU in 2019 and the US in 2021. Depression, autoimmunity and flu-like symptoms need monitoring, and whether clone reduction means fewer transformations is still being followed. In short, this is the PV drug that can shrink the mutant clone over years rather than just control blood counts.

## Fields

- Kind: Treatment
- Status: approved
- Last checked: 2026-09-08
- Tags: gap-fill
- Brand: Besremi
- Modality: Long-acting mono-pegylated interferon alfa
- Mechanism: Type I interferon signalling suppresses the JAK2-mutant clone preferentially, with immunomodulatory and antiproliferative effects; every-2-week dosing.
- Approvals: EU 2019: Polycythaemia vera without symptomatic splenomegaly; US 2021: Polycythaemia vera

## Sources

- Wikipedia: https://en.wikipedia.org/wiki/Ropeginterferon_alfa-2b
- Label (DailyMed): https://dailymed.nlm.nih.gov/dailymed/search.cfm?labeltype=all&query=ropeginterferon

## Connected records

- cancers: [Essential thrombocythaemia (ET)](https://onco.cc/cancers/essential-thrombocythaemia/), [Myeloproliferative neoplasms (PV, ET, myelofibrosis)](https://onco.cc/cancers/myeloproliferative-neoplasms/), [Polycythaemia vera (PV)](https://onco.cc/cancers/polycythaemia-vera/), [Primary myelofibrosis](https://onco.cc/cancers/primary-myelofibrosis/)
- technologies: [Cytokines & engineered cytokines](https://onco.cc/technologies/cytokine-therapy/)
- targets: [JAK2](https://onco.cc/targets/jak2/)
- companies: [AOP Health](https://onco.cc/companies/aop-health/), [PharmaEssentia](https://onco.cc/companies/pharmaessentia/)
- trials: [A Single-arm, Multicenter Study to Assess the Efficacy, Safety, and Tolerability of P1101 in Adults With ET](https://onco.cc/trials/nct05482971/), [A Study to Access Efficacy and Safety of P1101 in Chinese PV Patients Who Are Intolerant or Resistance to HU](https://onco.cc/trials/nct05485948/), [A Study to Assess Efficacy, Safety, and Tolerability of P1101 in Adult Patients With PV](https://onco.cc/trials/nct05481151/), [Extension Study of P1101 After Completion of Phase 2 Study in PV Patients or Phase 3 Study in ET Patients](https://onco.cc/trials/nct04655092/), [Low-PV](https://onco.cc/trials/low-pv/), [P1101 in Treating Patients With Early PMF or Overt PMF at Low or Intermediate-1 Risk](https://onco.cc/trials/nct06468033/), [PROUD-PV and CONTINUATION-PV](https://onco.cc/trials/proud-pv/), [Ropeginterferon Alfa-2b (P1101) vs. Anagrelide in Essential Thrombocythemia Patients With Hydroxyurea Resistance or Intolerance](https://onco.cc/trials/nct04285086/)
- terms: [Aquagenic pruritus](https://onco.cc/terms/aquagenic-pruritus/), [JAK2 V617F](https://onco.cc/terms/jak2-v617f/)
- ideas: [Clearing the JAK2 clone in polycythaemia vera: interferon plus mutant-selective inhibitors as a route to treatment-free remission](https://onco.cc/ideas/idea-pv-clone-directed-therapy/)

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