First-in-class Drug Rusfertide Approved for Polycythemia Vera

Therapy helps control excessive red blood cell production.

The U.S. Food and Drug Administration (FDA) has approved rusfertide (Mimrylo) for adult patients with polycythemia vera, a rare, slow-growing blood cancer that causes excessive blood cell production. 

Bone marrow with polycythemia vera appears crowded with all three major blood cell lineages (red blood cells, white blood cells, and platelets).

Rusfertide is a first-in-class drug that mimics the effects of the natural hormone hepcidin, which regulates iron absorption, storage, and distribution in the body. Specifically, the drug blocks the release of iron into the bloodstream. As a result of the block, there is less iron available for the bone marrow to make red blood cells, which helps keep the percentage of red blood cells in the blood within a safe limit.

The approval of rusfertide was based on results from the VERIFY multicenter, randomized, double-blind phase III trial that involved 293 adult participants with polycythemia vera who required frequent phlebotomies to control their red blood cell levels. Patients were randomly assigned (1:1) to receive either 19 mg of rusfertide or placebo for a period of 32 weeks alongside their ongoing treatment for polycythemia vera.

During the follow-up period, 76.9% of patients in the rusfertide arm maintained safe red blood cell levels without phlebotomy compared with 32.9% of patients in the placebo arm.

The recommended starting dose of rusfertide is 19 mg once a week, administered under the skin. The dose can be adjusted based on efficacy or safety to a maximum of 108 mg per week.

Polycythemia vera is a type of myeloproliferative neoplasm, a group of cancers in which the bone marrow produces too many red blood cells, white blood cells, or platelets. In the case of polycythemia vera, an excessive production of red blood cells causes the blood to thicken and can increase the risk of clots, leading to strokes or heart attacks. According to estimates, there are 65,000 people living with polycythemia vera in the United States, and median survival ranges from 14 to 27 years.

The FDA rendered its decision on August 28, 2026. Check this resource for updated information on all therapeutics regulated by the FDA.