FDA approves Mimrylo, first-of-its-kind drug for polycythemia vera

On August 28, 2026, the FDA approved Takeda Pharmaceutical and Protagonist Therapeutics' Mimrylo (rusfertide) for polycythemia vera, a rare blood cancer affecting 90,000 Americans. As the first hepcidin-mimicking therapy, Mimrylo restricts iron to control red blood cell overproduction. In the phase 3 VERIFY trial, 76.9% of Mimrylo patients required no phlebotomies, compared to 32.9% on placebo. Takeda plans to launch the drug within 48 hours, projecting peak global sales of $1 billion to $2 billion.

Mimrylo FDA approval polycythemia

• ▪On August 28, 2026, the U.S. Food and Drug Administration approved Mimrylo (rusfertide) to treat adults with polycythemia vera, a rare blood cancer.
• ▪Mimrylo was co-developed by Takeda Pharmaceutical and Protagonist Therapeutics under a 2024 licensing agreement, with Takeda now holding sole global commercialization rights.
• ▪Polycythemia vera is a rare blood cancer affecting roughly 90,000 Americans, causing bone marrow to overproduce red blood cells and raising risks of life-threatening clots, strokes, and heart attacks.

Hepcidin-mimicking mechanism of action

• ▪Mimrylo is the first approved treatment for polycythemia vera that mimics hepcidin, the body's master iron-regulating hormone.
• ▪Mimrylo works by restricting iron availability in the bloodstream, which prevents the bone marrow from overproducing red blood cells and helps keep red blood cell levels under control.
• ▪A key therapeutic goal in polycythemia vera is keeping the proportion of red blood cells in the blood, known as hematocrit, below 45% to reduce cardiovascular risks.

VERIFY trial efficacy results

• ▪The FDA's approval of Mimrylo was based on the VERIFY trial, a phase 3, multicenter, randomized, double-blind, placebo-controlled study of 293 adults with polycythemia vera.
• ▪In the VERIFY trial, patients with polycythemia vera were randomized 1:1 to receive either weekly subcutaneous injections of Mimrylo (starting at 19 mg) or a placebo over 32 weeks.
• ▪The most common adverse reactions reported for Mimrylo in the VERIFY trial were injection site reactions and anemia.

Phlebotomy reduction outcomes

• ▪In the VERIFY trial, 76.9% of patients treated with Mimrylo required no phlebotomies between weeks 20 and 32, compared to 32.9% of patients on placebo.
• ▪In addition to reducing the need for painful blood draws, Mimrylo treatment led to statistically significant improvements in patient symptoms such as fatigue compared to placebo.
• ▪Historically, polycythemia vera patients have relied on therapeutic phlebotomy, a procedure that involves regularly removing blood to keep red blood cell levels under control.

Takeda commercial pipeline strategy

• ▪Takeda Pharmaceutical paid Protagonist Therapeutics $300 million upfront in 2024 for licensing rights before buying out its partner's profit-share agreement earlier in 2026.
• ▪Mimrylo marks the second FDA approval secured by Takeda Pharmaceutical since Julie Kim became CEO in June 2026, following the approval of the narcolepsy treatment Orzeyful.
• ▪Takeda Pharmaceutical aims to launch zasocitinib, an oral TYK2 inhibitor for psoriasis, in the United States in the first half of 2027 to help offset generic erosion.
• ▪Takeda Pharmaceutical plans to make Mimrylo available to patients within 48 hours of FDA approval, projecting peak global sales for the drug in the range of $1 billion to $2 billion.

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