FDA officials have approved rusfertide, sold under the brand name Mimrylo, marking the first approval of a hepcidin mimetic peptide for adults with erythrocytosis. The agency and representatives from Takeda and Protagonist Therapeutics announced the decision late Friday, noting that the drug promises to spare patients with polycythemia vera from repeated painful phlebotomies. This new treatment offers a significant shift in how doctors manage the condition.
Polycythemia vera causes the body to produce too many red blood cells due to systemic iron deficiency. As iron flows into the bone marrow, red cell production escalates while depriving other tissues of necessary iron. Patients experience fatigue from the deficiency and face complications from too many red blood cells, including bone pain and an raised risk of stroke or blood clots.
Managing a complex blood disorder
The standard of care has relied on repeated phlebotomies to remove excess blood, a process that creates fluctuations in hematocrit levels. These ups and downs can cause damage over time, and the procedure itself is costly to health systems and draining for patients’ quality of life.
“People living with polycythemia vera have long faced the challenge of managing a chronic blood disorder with frequent blood draws,” Tanya Wroblewski, MD, said in the agency’s statement. “Today’s approval of [rusfertide] offers a new, first-in-class option that has the potential to meaningfully reduce patient burden.”
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Rusfertide works by restoring the body’s natural rhythms to regulate iron levels. This allows patients to maintain a steady hematocrit level, which is the percentage of red blood cells in the body’s overall supply. A healthy level is at or below 45%. These mechanisms differ from traditional approaches that rely on physical blood removal.
“When you control the iron in an optimal way, you are able to control the production of red blood cells,” Ramon Tiu, MD, told The American Journal of Managed Care.
Results from the VERIFY trial
The approval is based on phase 3 data from the VERIFY trial (NCT05210790), which was presented during the plenary session at the American Society of Clinical Oncology annual meeting in 2025. Andrew T. Kuykendall, MD, served as the lead investigator for the study.
VERIFY involved 293 patients randomized 1:1 to receive rusfertide or placebo. The group was 73% male with a median age of 57 years. Of the group, 83 patients taking rusfertide (56.5%) and 81 taking placebo (55.5%) also received cytoreductive therapy.
