FDA Approves Rusfertide for Polycythemia Vera

Key Takeaways

• In the United States, the FDA approval of Mimrylo (rusfertide) for adults with polycythemia vera makes it the first approved treatment for the condition that mimics hepcidin.
• In VERIFY, participants receiving rusfertide were more likely than placebo recipients to need no phlebotomy.
• Mimicking the iron-regulating hormone hepcidin limits the iron available to produce new red blood cells.

Polycythemia vera causes excess red blood cell production, and some adults still need repeated phlebotomy despite treatment. Phlebotomy removes blood from a vein to lower red-cell levels, but frequent procedures remain a burden for some patients. Adults who continued to need frequent phlebotomies despite treatment were enrolled in a trial of an iron-regulating approach to red-cell control.

Investigators enrolled 293 adults with polycythemia vera who needed frequent phlebotomies despite ongoing standard-of-care therapy in VERIFY, a multicenter, randomized, double-blind, placebo-controlled phase 3 trial. Participants were randomized in equal proportions to receive Mimrylo or placebo over 32 weeks while continuing background therapy.

In VERIFY, rusfertide treatment began at 19 mg subcutaneously once weekly and was titrated to maintain hematocrit below 45%. Maintaining hematocrit below that threshold is a stated treatment goal in polycythemia vera. The stated efficacy measure was the proportion of participants who did not meet criteria for phlebotomy between weeks 20 and 32.

During the 32-week period described by the Food and Drug Administration (FDA), 76.9% of Mimrylo recipients versus 32.9% of placebo recipients required no phlebotomies. Injection-site reactions and anemia were the most common adverse reactions identified by the FDA.

The FDA describes the stated efficacy measure using a narrower assessment window than the period attached to its no-phlebotomy comparison; those descriptions should not be treated as interchangeable. Needing less phlebotomy does not itself establish fewer thromboses, strokes, heart attacks, or other cardiovascular events, even though hematocrit control is a treatment goal. The starting dose and titration describe the trial regimen, not complete prescribing directions.

The approved hepcidin-mimetic approach offers a way to reduce phlebotomy needs in adults with polycythemia vera.

Clinician Questions

Does the Mimrylo approval for polycythemia vera apply only to adults needing frequent phlebotomies?

The FDA approved Mimrylo (rusfertide) for adults with polycythemia vera. VERIFY enrolled a narrower group needing frequent phlebotomies despite ongoing standard-of-care treatment; those enrollment criteria are not the complete labeled indication, and the FDA announcement alone does not establish the full label's detailed restrictions.

Did Mimrylo receive priority review for polycythemia vera, and which company received FDA approval?

Mimrylo (rusfertide), approved for adults with polycythemia vera, received priority review, and the FDA granted approval to Takeda Pharmaceuticals America, Inc.