Protagonist Therapeutics Secures Breakthrough Therapy Designation for Rusfertide in Polycythaemia Vera
Tuesday, August 26, 2025
Protagonist Therapeutics has announced that its investigational therapy rusfertide, a first-in-class hepcidin-mimetic peptide, has been granted Breakthrough Therapy Designation by the U.S. Food and Drug Administration (FDA) for the treatment of erythrocytosis in patients with polycythaemia vera (PV).
Protagonist Therapeutics is a biopharmaceutical company advancing novel peptide-based therapies. Its pipeline includes two Phase 3 assets: icotrokinra, an investigational oral peptide targeting the interleukin-23 receptor, with an NDA submitted in July 2025, and rusfertide, now advancing towards NDA submission by the end of the year. Rusfertide is being developed in collaboration with Takeda for polycythaemia vera. In addition, the company has preclinical programmes targeting IL-17 (PN-881), an obesity peptide (PN-477), and an oral hepcidin programme.
Rusfertide had previously been awarded Orphan Drug status and Fast Track designation in 2020.
Breakthrough Therapy Designation is intended to speed up the development and review of medicines for serious conditions when early clinical evidence suggests significant improvement over existing therapies. This designation also allows eligibility for priority review of a New Drug Application (NDA). Orphan Drug status provides additional incentives such as the possibility of extended market exclusivity.
The FDA decision was supported by positive results from the Phase 3 VERIFY trial. Data presented at the 2025 American Society of Clinical Oncology (ASCO) Annual Meeting showed that rusfertide met all primary and key secondary endpoints, including control of haematocrit, reduced reliance on phlebotomy, and improvements in patient-reported outcomes such as fatigue. These findings underline its potential to address the unmet medical needs of PV patients who cannot achieve adequate haematocrit control with current standard treatments.
Rusfertide is being co-developed with Takeda Pharmaceuticals under a worldwide collaboration and licence agreement signed in 2024. Protagonist remains primarily responsible for development through the NDA filing, which is expected by the end of 2025.
Source: Protagonist Therapeutics
