Protagonist, Takeda Phase 3 Study of Rusfertide Meets Endpoints in Polycythemia Vera

Protagonist Therapeutics, Inc. (PTGX) and Takeda Pharmaceutical Company Limited (TAK) announced positive topline results from the Phase 3 VERIFY study of rusfertide, a first-in-class investigational hepcidin mimetic peptide therapeutic for the treatment of polycythemia vera (PV). The study met its primary endpoint and all four key secondary endpoints, demonstrating the drug's efficacy and safety in treating PV.



The primary endpoint of the study was met, with a significantly higher proportion of clinical responders among rusfertide-treated patients with PV (77%) compared to those who received placebo (33%) during weeks 20-32; p<0.0001. The first key secondary endpoint, which is the pre-specified primary endpoint for European Union (EU) regulators, was also met, with a mean of 0.5 phlebotomies per patient in the rusfertide arm compared to 1.8 phlebotomies per patient in the placebo arm during weeks 0-32; p<0.0001.

The other three pre-specified key secondary endpoints, namely hematocrit control and patient-reported outcomes using PROMIS Fatigue SF-8a and MFSAF TSS-74, were also achieved with statistical significance. Rusfertide was generally well tolerated in the Phase 3 VERIFY trial, and safety was in line with previous rusfertide clinical studies. No new safety findings were observed in the study.

The success of the Phase 3 VERIFY study significantly enhances the commercialization prospects of rusfertide for Protagonist and Takeda. The study's positive data will strengthen the regulatory submission for rusfertide, increasing the likelihood of approval by regulatory authorities. Once approved, rusfertide will have the potential to become a first-in-class treatment for PV, addressing an unmet medical need and capturing a significant market share. The positive results also validate Protagonist's peptide-based drug discovery platform, further bolstering the company's reputation and potential for future partnerships. Additionally, the milestone payment of $25 million earned by Protagonist following the study results reinforces the financial viability of the collaboration between Protagonist and Takeda.

In conclusion, the positive topline results from the Phase 3 VERIFY study of rusfertide in polycythemia vera patients demonstrate the drug's efficacy and safety. With a strong regulatory framework supporting its development and a significant market opportunity driven by the prevalence of the disease and the need for disease-modifying agents, rusfertide is well-positioned to compete in the market and capture a significant market share. The success of the study also validates Protagonist's peptide-based drug discovery platform and strengthens the collaboration between Protagonist and Takeda.