On March 2, 2026 Takeda (TSE:4502/NYSE:TAK) and Protagonist Therapeutics, Inc. ("Protagonist") (NASDAQ:PTGX) reported that the U.S. Food and Drug Administration (FDA) accepted the New Drug Application (NDA) and granted Priority Review for rusfertide. Rusfertide is an investigational, first-in-class hepcidin mimetic peptide therapeutic for the treatment of adults with polycythemia vera (PV). The FDA has set a Prescription Drug User Fee Act (PDUFA) goal date in the third quarter of this calendar year. In addition to Priority Review, rusfertide has received Breakthrough Therapy designation, Orphan Drug designation and Fast Track designation from the U.S. FDA.
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PV is characterized by the overproduction of red blood cells (erythrocytosis), which increases blood viscosity, or thickness, and can result in life threatening thrombotic events. Hematocrit is the ratio of red blood cells to the total amount of blood in the body. Achieving and maintaining controlled hematocrit levels of <45% is the primary treatment goal in PV to prevent thrombotic events and alleviate burdensome symptoms.
"There is an urgent need for innovative treatment options in polycythemia vera, where patients currently face limited therapeutic choices to control their hematocrit and significant symptom burden," said Andy Plump, M.D., Ph.D., president of R&D at Takeda. "The FDA’s acceptance of our NDA brings us closer to potentially offering a first-in-class therapy that could meaningfully improve clinical outcomes and quality of life. This milestone is a reflection of our successful partnership with Protagonist and Takeda’s unwavering commitment to advancing innovative treatments in hematologic cancers where significant unmet needs persist."
The NDA for rusfertide was primarily based on the positive 32-week primary analysis and 52-week results from the Phase 3 global randomized VERIFY study (NCT05210790), as well as four-year efficacy and safety data from the Phase 2 REVIVE study (NCT04057040) and long-term extension THRIVE study (NCT06033586). In the VERIFY study, rusfertide met the primary endpoint and all four key secondary endpoints. Patients receiving rusfertide plus current standard of care demonstrated a higher response rate compared to current standard of care. This included hematocrit control, a reduction in phlebotomy requirements and improvement in pre-specified patient reported outcomes of fatigue and symptom burden. Rusfertide was generally well-tolerated through 52 weeks of treatment. The most common treatment-emergent adverse events (AEs) in rusfertide-treated patients were injection site reactions (47.4%), anemia (25.6%) and fatigue (19.6%), which were mainly grade 1 or 2. Serious AEs occurred in 8.1% of overall rusfertide-treated patients.
"Rusfertide exemplifies Protagonist’s end-to-end expertise, from exploring a novel hepcidin mimetic mechanism to address unmet needs in polycythemia vera to discovering the peptide and driving its clinical development through NDA filing. We are very pleased with the FDA granting rusfertide Priority Review and look forward to its potential approval in 2026," said Dinesh V. Patel, Ph.D., Protagonist President and CEO. "We have identified a great partner in Takeda as rusfertide progresses toward this milestone, thereby bringing a successful closure to our more than decade-long journey from concept-to-commercialization."
In January 2024, Protagonist and Takeda entered into a worldwide license and collaboration agreement for rusfertide. Protagonist discovered rusfertide and led its development through Phase 3 studies, with Takeda responsible for implementing the regulatory strategy for the U.S. NDA filing and for leading any future global regulatory filings. Protagonist holds an option to co-commercialize in the U.S. through a 50/50 profit and loss share structure or to opt-out of this structure, providing Takeda with a worldwide license pursuant to the license and collaboration agreement.
About Rusfertide
Rusfertide is a first-in-class investigational subcutaneous treatment that mimics the action of hepcidin, a natural hormone that regulates iron homeostasis and red blood cell production. By targeting the underlying mechanism of iron dysregulation in polycythemia vera, rusfertide aims to reduce excess red blood cell production and help patients achieve sustained hematocrit control. Rusfertide is administered once weekly via subcutaneous self-injection and has been generally well-tolerated in clinical trials to date.
About VERIFY
The Phase 3 VERIFY study (NCT05210790) is an ongoing, three-part, global, randomized, placebo-controlled study evaluating rusfertide in 293 patients with polycythemia vera over a 156-week period, with treatment extension for participants who are continuing to derive benefit from rusfertide beyond the 156-week treatment period. The study is evaluating the efficacy and safety of once-weekly, subcutaneously self-administered rusfertide in patients with uncontrolled hematocrit who are phlebotomy-dependent despite current standard of care treatment, which could include phlebotomy, hydroxyurea, interferon and/or ruxolitinib. The primary endpoint of the study was the proportion of patients achieving a response during Weeks 20-32, which was defined as the absence of "phlebotomy eligibility." To meet phlebotomy eligibility, patients in the study were required to have: confirmed hematocrit ≥45% that was ≥3% higher than their baseline hematocrit value, or hematocrit ≥48%.
All patients have completed their participation in the randomized, placebo-controlled portion of the study evaluating the efficacy and safety of rusfertide plus current standard of care versus placebo plus current standard of care and are now in the open-label portions of the study.
About REVIVE and THRIVE
The Phase 2 REVIVE study (NCT04057040) evaluated rusfertide in adult patients with polycythemia vera and consisted of three parts, including 70 patients in the dose-finding Part 1 (28 weeks), 59 patients in the blinded, placebo-controlled, randomized withdrawal Part 2 (13 weeks) and 58 patients in the Part 3 open-label expansion (52 weeks). The THRIVE study (NCT06033586) is an ongoing, open-label extension study evaluating the long-term durability of response and safety profile of rusfertide in patients with polycythemia vera. The study includes 46 patients who previously participated in REVIVE. Patients eligible to transition to the THRIVE study completed the open-label extension portion of REVIVE, ≥12 months of rusfertide therapy and had an end-of-treatment visit. THRIVE is designed to further assess the maintenance of hematocrit control, reduction in the need for therapeutic phlebotomy and overall safety of once-weekly, subcutaneous rusfertide over an additional two-year treatment period.
About Polycythemia Vera (PV)
Polycythemia vera (PV) is characterized by the overproduction of red blood cells (erythrocytosis), which increases blood viscosity, or thickness, and can result in life threatening thrombotic events such as stroke, deep vein thrombosis and pulmonary embolism. Hematocrit is the ratio of red blood cells to the total amount of blood in the body. Achieving and maintaining controlled hematocrit levels of <45% is the primary treatment goal in PV to prevent thrombotic events and alleviate burdensome symptoms, including severe fatigue, difficulty in concentrating, night sweats and pruritus.
(Press release, Takeda, MAR 2, 2026, View Source [SID1234663197])