WATERTOWN, Mass. — September 9, 2026

Disc Medicine, Inc. presented positive initial results from the Phase 2 RESTORE-PV trial of DISC-3405 in patients with polycythemia vera (PV) at the 14th Society of Hematologic Oncology (SOHO) Annual Meeting. The data showed that DISC-3405 increased hepcidin and reduced serum iron, translating into controlled hematocrit, fewer phlebotomy procedures and initial improvements in symptom burden. The findings represent an important clinical milestone for DISC-3405, an investigational monoclonal antibody targeting TMPRSS6, and mark the first demonstration of phlebotomy reduction in PV with a TMPRSS6-targeting antibody. Disc said the results support its strategy of using iron restriction to address hematocrit control while potentially reducing dependence on repeated blood removal. The company also presented updated information from its selcodebart program in myelofibrosis, reinforcing its broader focus on hematologic oncology.

DISC-3405 Reduces Phlebotomy Requirements

RESTORE-PV enrolled 40 adults with polycythemia vera across two cohorts, with participants undergoing observation, dose escalation and maintenance treatment with subcutaneous DISC-3405. Cohort A evaluated 300 mg every two weeks, while Cohort B evaluated 300 mg every four weeks. At the data cutoff, all 20 Cohort A participants had been dosed, including 13 who completed 26 weeks, while 18 of 20 participants in Cohort B had received treatment. In Cohort A, DISC-3405 demonstrated dose-proportional pharmacokinetics, increased hepcidin, reduced serum iron and increased ferritin. Importantly, mean hematocrit remained stably below 45% through Week 26, while phlebotomy requirements declined substantially. Among the 13 participants completing 26 weeks, mean total phlebotomy events decreased from 4.0 during the 26-week baseline period to 0.6 during the 26 weeks after Day 1 (p<0.0001). In addition, 61.5% remained completely phlebotomy-free through Week 26.

Hepcidin Activation Supports Iron Restriction Strategy

DISC-3405 is designed to increase hepcidin production and suppress circulating iron availability, providing a differentiated approach to controlling excessive red blood cell production in PV. TMPRSS6, also known as matriptase-2, is a regulator of hepcidin, making the pathway an attractive target for diseases in which limiting iron availability may reduce erythropoiesis. Disc’s initial RESTORE-PV findings suggest that pharmacodynamic effects on hepcidin and iron metabolism can translate into clinically relevant hematologic outcomes. Among patients who completed the first maintenance period, 77.8% remained phlebotomy-free during the evaluated period. Treatment was generally well tolerated across the study cohorts, with adverse events consistent with the underlying disease and a low incidence of mild, self-limited injection-site reactions. Disc said the data support further development of a dosing approach intended to provide durable disease control with convenient and controllable administration.

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Disc Medicine Expands Hematologic Development Pipeline

The RESTORE-PV results strengthen Disc Medicine’s broader development strategy across serious hematologic diseases, with DISC-3405 advancing in both polycythemia vera and sickle cell disease. The company plans to provide an additional RESTORE-PV update and initial Phase 1b data from DISC-3405 in sickle cell disease by the end of 2026. DISC-3405 was in-licensed from Mabwell Therapeutics in 2023 and has previously demonstrated clinical proof-of-mechanism in healthy volunteers. Disc is also advancing selcodebart (DISC-0974) for anemia associated with myelofibrosis and expects to receive FDA feedback and outline potential pivotal development plans by year-end. With evidence of reduced phlebotomy, sustained hematocrit control and improved symptoms in PV, DISC-3405 is emerging as a potentially differentiated iron-restriction therapy while Disc Medicine builds a broader clinical portfolio targeting fundamental pathways in red blood cell biology and iron homeostasis.

Source: Disc Medicine,press release