FDA approves first-in-class Mimrylo for rare blood cancer

The U.S. FDA approved Mimrylo (rusfertide), developed by Protagonist Therapeutics and commercialized by Takeda, for treating erythrocytosis in adults with polycythemia vera (PV).

PV is a rare, slow-growing blood cancer in which the bone marrow produces too many red blood cells, thickening the blood and raising the risk of clots, strokes, and heart attacks.

Mimrylo is the first approved hepcidin-mimetic therapy for PV. It is administered as a once-weekly injection and is designed to restrict iron availability, helping control red-blood-cell production.

In the Phase 3 VERIFY trial, 76.9% of treated patients achieved the study’s response criteria during weeks 20–32, reducing the need for therapeutic phlebotomy—repeated blood-removal procedures traditionally used to manage PV.

Takeda said the treatment would be available shortly after approval. Reports indicate a list price of about $4,200 per vial, or approximately $218,400 annually if one vial is used weekly.

The approval triggers milestone payments to Protagonist, which will also receive royalties while Takeda holds global commercialization rights.