Takeda Pharmaceutical (TAK) has secured FDA approval for Mimrylo, a first-of-its-kind therapy targeting polycythemia vera, a rare and potentially life-threatening blood cancer.
Polycythemia vera affects approximately 90,000 people in the United States and causes the bone marrow to overproduce red blood cells, thickening the blood dangerously.
The overproduction of red blood cells significantly raises patients’ risk of life-threatening clots, strokes, and heart attacks if left unmanaged.
Mimrylo, known generically as rusfertide, is the first approved treatment for polycythemia vera that mimics hepcidin, a hormone that naturally regulates iron levels in the body.
By restricting the iron available for red blood cell production, Mimrylo helps reduce overproduction and keeps hematocrit levels within safer thresholds.
For decades, the primary treatment relied on therapeutic phlebotomy, a procedure involving the regular removal of blood to control red blood cell levels.
The approval was supported by the VERIFY trial, a multicenter, randomized, double-blind, placebo-controlled phase 3 study involving 293 adults with polycythemia vera who required frequent phlebotomies despite standard-of-care therapy.
Patients were randomised 1:1 to receive either Mimrylo or placebo over 32 weeks, with Mimrylo starting at 19 mg administered subcutaneously once weekly and titrated to maintain hematocrit below 45%.
Results showed 76.9% of patients on Mimrylo required no phlebotomies during the 32-week period, compared to just 32.9% of those on placebo.
The most common adverse reactions observed in the trial were injection site reactions, occurring in 56% of patients, and anemia, reported in 16% of patients.
Mimrylo received priority review from the FDA, with the approval formally granted to Takeda Pharmaceuticals America, Inc.
The drug is being commercialised by Takeda under a worldwide licence and collaboration agreement with Protagonist Therapeutics, which originally discovered rusfertide and led its development through Phase 3.
Protagonist elected to opt out of the collaboration in April 2026, triggering $275 million in payments consisting of a $200 million opt-out fee and a $75 million approval milestone.
Protagonist remains eligible to receive up to an additional $875 million in potential milestone payments, along with tiered royalties ranging from 14% to 29% on worldwide net sales.
Teresa Bitetti, president of Takeda’s global oncology business unit, told Reuters that Mimrylo would be made available to patients within 48 hours of FDA approval.
Takeda is projecting peak global annual sales for Mimrylo in the range of $1 billion to $2 billion, signalling strong commercial confidence in the new therapy.