Takeda and Protagonist win first-in-class FDA approval for Mimrylo (rusfertide) in polycythemia vera

The US Food and Drug Administration has approved TakedaDealroom has a profile for this one. Try Dealroom →'s Mimrylo (rusfertide), the first drug of its kind cleared for polycythemia vera — a rare, chronic blood disorder in which the bone marrow makes too many red blood cells, thickening the blood and raising the risk of clots, heart attack and stroke. The drug was discovered by Protagonist Therapeutics and is partnered with Takeda; the approval triggered a $275m milestone payment to Protagonist.

Until now, the main way to control the disease has been repeated phlebotomy — literally drawing off blood at regular intervals, much like a blood donation, to keep red-cell levels down. Mimrylo works differently: it is a hepcidin mimetic , meaning it mimics a natural hormone the body uses to regulate iron. By limiting the iron available to make new red blood cells, it keeps the blood count in check without the need for routine blood-letting. It is the first therapy of this type approved for the condition.

Approval was based on the Phase 3 VERIFY trial, in which 76.9% of patients treated with rusfertide achieved and maintained a response during weeks 20 to 32, compared with a small fraction on placebo, alongside a marked reduction in the number of phlebotomies patients needed. For a disease historically managed by draining blood, that is a meaningful shift in the treatment routine.

Source: US FDA, 28 August 2026.