Protagonist Therapeutics (PTGX) and Takeda (TAK) said Monday that a phase 3 study of investigational drug rusfertide as a potential add-on to standard of care treatment for polycythemia vera, a form of blood cancer, met the primary and key secondary endpoints.

The companies said Protagonist will earn a milestone payment of $25 million upon the completion of the clinical study report, while Takeda expects no material impact on its financial results for fiscal year 2024 ending March.

The trial met the primary endpoint, with 77% of rusfertide-treated patients achieving response, higher than the 33% in the placebo group during weeks 20 to 32, according to a joint statement.

Secondary endpoints were also met, including an average of 0.5 phlebotomies per patient in the rusfertide arm compared to 1.8 phlebotomies per patient in the placebo arm during the 32 weeks of treatment, hematocrit control, and patient-reported outcomes, the companies said.

The companies also said the drug was generally well-tolerated with no new safety findings observed.

Protagonist's shares climbed more than 10% in recent premarket activity and Takeda's shares added 1.2%.