Rusfertide: evidence, FDA status and research

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Rusfertide is talked about as the drug that lets people with polycythemia vera stop having blood drawn every few weeks.

Studies say

Two randomized trials show rusfertide keeps hematocrit below 45 percent and frees most patients from phlebotomy, with injection site reactions as the main side effect, which earns an A for its approved use.

Why grade A. Approval rested on the phase 3 VERIFY trial, a randomized, double-blind, placebo-controlled study of 293 adults with phlebotomy-dependent polycythemia vera, preceded by the phase 2 REVIVE trial of 70 patients with a randomized withdrawal phase. Both showed large, consistent reductions in phlebotomy need. Long-term data run to about four years in open-label follow-up; what is missing is evidence on thrombosis and survival. ¹³

FDA. Rusfertide was approved by the FDA on August 28, 2026, as Mimrylo (Takeda) for adults with polycythemia vera, to control red cell overproduction and reduce the need for therapeutic phlebotomy. It is the first hepcidin mimetic approved for any use. ²³

Written from 3 cited sources. Fact-checked 2026-10-27: 16 claims checked, 2 corrected. Last refreshed 2026-10-27. Not physician reviewed.

Evidence checklist

Randomised controlled trial VERIFY phase 3; REVIVE phase 2yes
Human study over 100 people VERIFY, 293 adultsyes
More than one research group Article does not say who ran the trialsno information
Clinical outcomes, not surrogate markers Phlebotomy need; thrombosis and survival unknownno
Human safety data beyond case reports About four years of open-label follow-upyes

Drawn from the cited studies below. A dash means the sources give no information.

What it is

Rusfertide (PTG-300) is a synthetic peptide that mimics hepcidin, the liver hormone that controls how much iron reaches the bloodstream. It was developed by Protagonist Therapeutics and licensed to Takeda, and is given as a weekly subcutaneous injection that patients can self-administer. ¹²

Polycythemia vera is a chronic blood cancer in which a mutation, usually in the JAK2 gene, makes the bone marrow produce too many red cells. Thick blood raises the risk of clots, stroke and heart attack. Standard care is to keep the hematocrit below 45 percent by periodically removing blood (therapeutic phlebotomy), often with hydroxyurea or interferon added. Phlebotomy works but is disruptive and leaves many patients iron-deficient and symptomatic between visits. ¹³

How it works

Hepcidin binds ferroportin, the only known protein that exports iron from cells into the blood, and triggers its destruction. When hepcidin is high, iron stays locked in gut cells, liver cells and macrophages and little reaches the bone marrow. Red cell production depends on iron, so restricting it slows the overproduction in polycythemia vera without suppressing the marrow in other ways. Rusfertide copies that action with a more stable molecule. Because it works by iron restriction and does not kill cells, white cells and platelets are largely unaffected, and because it does not remove blood, patients do not develop the iron deficiency that repeated phlebotomy causes. ¹

What human research shows

REVIVE, the phase 2 trial, enrolled 70 patients with polycythemia vera who needed frequent phlebotomies. During 28 weeks of open-label dosing, phlebotomy requirements fell sharply and hematocrit stayed below 45 percent in most patients. In the randomized withdrawal phase, 59 patients were assigned to continue rusfertide or switch to placebo for 12 weeks: 60 percent of those on rusfertide maintained their response versus 17 percent on placebo. Symptom scores for fatigue and concentration improved. ¹

VERIFY, the phase 3 trial, randomized 293 adults to weekly rusfertide or placebo on top of their existing treatment. Between weeks 20 and 32, 77 percent of rusfertide patients needed no phlebotomy compared with 33 percent on placebo. Hematocrit control, phlebotomy counts and patient-reported fatigue all favored rusfertide. Open-label follow-up from the earlier trials now extends to about four years, with phlebotomy rates remaining far below baseline. ³

Study	Model	Finding
VERIFY phase 3	Humans, n=293 with phlebotomy-dependent polycythemia vera, randomized, double-blind, placebo-controlled	77 percent of rusfertide patients needed no phlebotomy between weeks 20 and 32 versus 33 percent on placebo. ³
REVIVE phase 2	Humans, n=70 in 28-week open-label dosing, then 59 randomized to continue or withdraw for 12 weeks	60 percent maintained response on rusfertide versus 17 percent after switching to placebo, with fewer phlebotomies and better symptom scores. ¹
Mimrylo label	FDA prescribing information	Approved for adults with polycythemia vera, with injection site reactions and anemia as the most common adverse reactions. ²

Safety

Injection site reactions, redness, itching and swelling where the drug is injected, are the most common adverse effect, reported by a majority of patients in REVIVE, though they were mild and rarely led to stopping. Anemia and fatigue were also reported. In REVIVE, a small number of skin cancers (basal and squamous cell) occurred in patients with prior skin cancer or hydroxyurea exposure, which prompted an FDA clinical hold in 2021 that was lifted after review; the rate did not exceed background in the larger trial. Thromboembolic events still occur in treated patients, and whether rusfertide reduces clot risk compared with phlebotomy has not been shown. Nearly all participants were white and most were over 50, so data in other populations are sparse. ¹³

Questions for your clinician

Does this lower the risk of clots, or only the need for phlebotomy?
What skin checks are advised, given the skin cancers seen in trials?
How does it fit with my current polycythaemia vera treatment?

Questions people ask

Is rusfertide FDA-approved?

Yes, since August 28, 2026, as Mimrylo for adults with polycythemia vera. It had priority review on the strength of the VERIFY trial. ²³

How does rusfertide reduce red blood cells without chemotherapy?

It mimics hepcidin, the hormone that tells the body to hold iron inside storage cells. Less iron reaches the bone marrow, so fewer red cells are made. It does not kill marrow cells, which is why white cells and platelets are largely spared. ¹

Does it replace phlebotomy?

For most patients in the trials it did: about three-quarters needed no phlebotomy during the main assessment period, against a third on placebo. It was tested on top of existing therapy, so patients taking hydroxyurea or interferon continued those drugs. ³

Which adverse events were seen in trials?

Mostly injection site reactions, which were common but mild, plus anemia and fatigue. A cluster of skin cancers in the early trial led to a temporary FDA hold in 2021; the larger trial did not show an excess. Whether it lowers clot risk over the long term is not known. ¹³

Citations

Kremyanskaya 2024, N Engl J Med: rusfertide, a hepcidin mimetic, for control of erythrocytosis in polycythemia vera (REVIVE) doi.org
Mimrylo (rusfertide) prescribing information drugs.com
ASCO Post, Aug 2026: FDA approves rusfertide for erythrocytosis in polycythemia vera (VERIFY results) ascopost.com