---
title: "Rusfertide"
canonical_url: https://peptidelibrary.app/library/rusfertide
description: "FDA-approved hepcidin mimetic peptide (Mimrylo, August 2026) for erythrocytosis in adults with polycythemia vera. A weekly subcutaneous injection that limits the iron available for making red blood cells."
updated: 2026-10-30
publisher: Peptide Library
notice: "Research and educational use only. Not medical advice."
---

# Rusfertide

Rusfertide (also called Mimrylo or PTG-300) is an FDA-approved hepcidin mimetic (synthetic cyclic peptide). Rusfertide mimics hepcidin, the hormone that regulates iron in the body. It blocks ferroportin, the transporter that releases iron into the blood, which limits the iron available for making red blood cells and lowers hematocrit.

FDA-approved hepcidin mimetic peptide (Mimrylo, August 2026) for erythrocytosis in adults with polycythemia vera. A weekly subcutaneous injection that limits the iron available for making red blood cells.

Also known as: Mimrylo, PTG-300, TAK-121.

## Classification

- Type: FDA-approved hepcidin mimetic (synthetic cyclic peptide)
- Mechanism class: Hepcidin Mimetic
- Development stage: Approved product
- Regulatory class: FDA-approved medicine

## Mechanism

Rusfertide mimics hepcidin, the hormone that regulates iron in the body. It blocks ferroportin, the transporter that releases iron into the blood, which limits the iron available for making red blood cells and lowers hematocrit. In healthy adults, serum iron was lowest 24 to 48 hours after a dose.

Targets: Ferroportin.

Origin: Synthetic cyclic peptide developed by Protagonist Therapeutics as PTG-300; the US product is from Takeda.

## Properties

- Sequence: S6,S16-cyclo[N-isovaleryl-Asp-Thr-His-Phe-Pro-Cys-Ile-Nε-(N-palmitoyl-γ-Glu)-Lys-Phe-Glu-Pro-Arg-Ser-Lys-Gly-Cys-Lys-NH2]
- Molecular formula: C114H181N27O28S2
- Molecular weight: 2,442.0 g/mol
- CAS number: 1628323-80-7
- Studied routes: Subcutaneous

## Evidence

- Evidence level: FDA Approved
- Highest documented: Regulatory review (FDA label)
- Human trials: 4
- Controlled human trials: 2
- Preclinical sources: 1
- Latest source: 2026

Each step shows whether the sources Peptide Library has reviewed include that kind of research. Counts are reviewed sources, not every study ever published. Reviews and programme summaries that describe human use are shown as "reported", not as trials, and registered trials without published results are listed but not counted. A higher step means research has progressed further; it does not mean a compound works better or is safer. Compounds whose evidence has not been reviewed yet show "Not reviewed" instead of a guess.

### Studies

1. MIMRYLO (rusfertide) for injection — FDA prescribing information, DailyMed. Regulatory label (FDA), human. Population: Adults with erythrocytosis due to polycythemia vera. Control of erythrocytosis, keeping hematocrit below 45% [Source](https://dailymed.nlm.nih.gov/dailymed/drugInfo.cfm?setid=101aff01-31ed-4841-a8b6-0a5a8503189b)
2. Kuykendall AT et al. VERIFY: A Phase III Trial of Rusfertide Versus Placebo in Phlebotomy-Dependent Patients With Polycythemia Vera Receiving Standard-of-Care Therapy. J Clin Oncol. 2026. 2026. Controlled human trial. Population: Adults with phlebotomy-dependent polycythemia vera on standard care (147 on rusfertide, 146 on placebo). 77% had no phlebotomy eligibility in weeks 20 to 32, versus 33% on placebo [Source](https://pubmed.ncbi.nlm.nih.gov/42868322/)
3. Kremyanskaya M et al. Rusfertide, a Hepcidin Mimetic, for Control of Erythrocytosis in Polycythemia Vera. N Engl J Med. 2024. 2024. Controlled human trial. Population: Adults with phlebotomy-dependent polycythemia vera (n=70; 59 entered the randomized withdrawal part). 60% responded on rusfertide versus 17% on placebo during the withdrawal part [Source](https://pubmed.ncbi.nlm.nih.gov/38381675/)
4. Kowdley KV et al. Rusfertide for the treatment of iron overload in HFE-related haemochromatosis: an open-label, multicentre, proof-of-concept phase 2 trial. Lancet Gastroenterol Hepatol. 2023. 2023. Human study (early or uncontrolled). Population: Adults with HFE-related hemochromatosis on maintenance phlebotomy (n=16). 15 of 16 patients needed no phlebotomy during treatment [Source](https://pubmed.ncbi.nlm.nih.gov/37863080/)
5. Modi NB et al. Multiple-Dose Pharmacokinetics, Pharmacodynamics, Safety, and Tolerability of Subcutaneous Rusfertide, a Hepcidin Mimetic, in Healthy Subjects. Clin Pharmacol Drug Dev. 2025. 2025. Human study (early or uncontrolled). Population: Healthy adults (n=18). Pharmacokinetics and iron and blood-count effects did not differ meaningfully by injection site [Source](https://pubmed.ncbi.nlm.nih.gov/39888264/)
6. MIMRYLO (rusfertide) for injection — FDA prescribing information, section 8.1, DailyMed. Preclinical: animal or lab study. Population: Pregnant rats and rabbits. Malformations in rats and embryo-fetal death in rabbits at exposures below the human exposure at the maximum dose. Limitations: Lab or animal research: not evidence of a human effect or dose. [Source](https://dailymed.nlm.nih.gov/dailymed/drugInfo.cfm?setid=101aff01-31ed-4841-a8b6-0a5a8503189b)

## Safety

Side effects: Injection site reactions (56% versus 33% on placebo); Anemia (16% versus 4.1%); Thrombocytosis (8% versus 0.7%); Shortness of breath (8% versus 1.4%).

Risks: New or worsening thrombocytosis: platelets rose an average of 31% within 4 weeks, and 6% of patients passed 1,000 x 10^9/L; Embryo-fetal toxicity: malformations and fetal death in animal studies, so the label advises contraception during treatment and for at least 30 days after; Breastfeeding is not recommended during treatment and for 30 days after; Antibodies to rusfertide formed in 34% of VERIFY patients, some cross-reacting with human hepcidin, with no apparent effect on efficacy or safety; Safety and effectiveness not established in children.

Human safety basis: FDA prescribing information

## Regulatory status

Rusfertide is an FDA-approved product for specific labelled indications. Approval does not extend to the research contexts described on this page, and approved products are prescription medicines.

- FDA status: Approved
- Availability: Prescription-Only

## Frequently asked questions

### What is rusfertide?

Rusfertide is a weekly injectable medicine sold as Mimrylo for people with polycythemia vera, a blood cancer in which the bone marrow makes too many red blood cells. It is a synthetic cyclic peptide that copies the action of hepcidin, the hormone that controls iron.

### How does rusfertide work?

Rusfertide blocks ferroportin, the transporter that moves iron into the blood. With less iron reaching the bone marrow, fewer red blood cells are made and hematocrit falls. It treats too many red cells by limiting a raw material, not by removing blood.

### Is rusfertide FDA approved?

Yes. FDA approved rusfertide as Mimrylo on 28 August 2026 (NDA 220605, Takeda) for erythrocytosis in adults with polycythemia vera. Other uses studied, such as hemochromatosis, are not on the label.

### Does rusfertide replace phlebotomy?

For many patients in the phase 3 VERIFY trial it did for the period studied: 77% had no need for phlebotomy in weeks 20 to 32, versus 33% on placebo. Patients stayed on their usual care in that trial, and hematocrit still has to be monitored.

### What compounds are similar to rusfertide?

This library has no other hepcidin mimetic. Pegcetacoplan and motixafortide are listed alongside it as peptides used in blood disorders, but they act on different targets and are not substitutes.

## References

- [MIMRYLO (rusfertide) for injection — FDA prescribing information, DailyMed](https://dailymed.nlm.nih.gov/dailymed/drugInfo.cfm?setid=101aff01-31ed-4841-a8b6-0a5a8503189b)
- [NDA 220605 approval letter — FDA, August 2026](https://www.accessdata.fda.gov/drugsatfda_docs/appletter/2026/220605Orig1s000ltr.pdf)
- [VERIFY: A Phase III Trial of Rusfertide Versus Placebo in Phlebotomy-Dependent Patients With Polycythemia Vera — J Clin Oncol, 2026](https://pubmed.ncbi.nlm.nih.gov/42868322/)
- [Rusfertide, a Hepcidin Mimetic, for Control of Erythrocytosis in Polycythemia Vera — N Engl J Med, 2024](https://pubmed.ncbi.nlm.nih.gov/38381675/)
- [Rusfertide for the treatment of iron overload in HFE-related haemochromatosis — Lancet Gastroenterol Hepatol, 2023](https://pubmed.ncbi.nlm.nih.gov/37863080/)
- [Multiple-Dose Pharmacokinetics, Pharmacodynamics, Safety, and Tolerability of Subcutaneous Rusfertide — Clin Pharmacol Drug Dev, 2025](https://pubmed.ncbi.nlm.nih.gov/39888264/)
- [NCT05210790 — VERIFY phase 3 trial of rusfertide](https://clinicaltrials.gov/study/NCT05210790)

Note: Dose figures are left out of this Markdown version. See the cited sources.