Rusfertide

Rusfertide imitates hepcidin, the central regulator of iron availability. Protagonist Therapeutics and Takeda developed it for polycythemia vera, a myeloproliferative disease in which excessive red cells thicken blood and increase clot risk. Mimrylo is administered under the skin.

Hepcidin-mimetic binding inhibits ferroportin, the iron-export channel on intestinal cells and iron stores. Less iron reaches the marrow, limiting the supply required to produce red blood cells. This helps control hematocrit—the fraction of blood occupied by red cells—and reduces repeated phlebotomy requirements. Positive randomized Phase 2 and Phase 3 studies support that strategy.

FDA approved Mimrylo on August 28, 2026, for adults with polycythemia vera, based on Phase 3 VERIFY. It is the first approved hepcidin-mimetic peptide in this setting.

A hematologist may use rusfertide as part of polycythemia-vera management to control hematocrit and reduce dependence on blood removal. The aim is management of excessive red-cell production and the associated clotting-risk context.

The most common adverse effects are injection reactions and anemia. Important risks include new or worsening thrombocytosis, meaning elevated platelets, and harm to an unborn baby.