Disc Medicine reported that DISC-3405 reduced mean total phlebotomy events from 4.0 to 0.6 over 26 weeks in Cohort A of its RESTORE-PV Phase 2 trial. The results also showed mean hematocrit below 45%, initial symptom improvement and 61.5% of participants remaining phlebotomy-free, supporting further clinical development.

Key Highlights

  • Mean total phlebotomy events fell from 4.0 at baseline to 0.6 after Day 1 over 26 weeks, with p<0.0001.
  • Mean hematocrit remained stably below 45% through week 26 in Cohort A.
  • DISC-3405 increased hepcidin, reduced serum iron and increased ferritin in Cohort A.

Disc Medicine, Inc. (NASDAQ: IRON) reported that mean hematocrit in Cohort A remained below 45% through 26 weeks in initial RESTORE-PV Phase 2 results for DISC-3405. The company said the result was accompanied by an initial improvement in symptom burden. DISC-3405 also reduced phlebotomy events in Cohort A and was generally well tolerated across Cohorts A and B, with injection-site reactions described as mild and self-limited.

Phlebotomy Reduction in Cohort A

Among participants who completed 26 weeks, mean total phlebotomy events declined from 4.0 during the baseline period to 0.6 after Day 1, with p<0.0001. A total of 61.5% remained entirely phlebotomy-free after baseline through 26 weeks. Among those completing the first maintenance period, 77.8% stayed phlebotomy-free during that period. The efficacy findings were presented for Cohort A, while baseline and safety findings covered both cohorts.

DISC-3405 Trial Design

RESTORE-PV is a multi-center, open-label Phase 2 trial in adult patients with polycythemia vera. Participants first underwent an observation period, followed by a 12-week dose escalation and subcutaneous maintenance treatment with DISC-3405. The study used dosing every two weeks for Cohort A and every four weeks for Cohort B. At the data cut, all Cohort A participants had received dosing, while 18 participants in Cohort B had been dosed; 13 Cohort A participants had completed 26 weeks. Across escalation and maintenance, Cohort A results showed dose-proportional pharmacokinetics, increased hepcidin, lower serum iron and higher ferritin. The company also said treatment was generally well tolerated across both cohorts, with adverse events consistent with the underlying disease.

RESTORE-PV Update Planned

Disc Medicine presented the initial RESTORE-PV results at the 2026 Society of Hematologic Oncology annual meeting. The data were presented in a poster session and will be featured in an oral presentation on Sep 10. The company plans to provide another RESTORE-PV update by the end of 2026, along with initial data from the Phase 1b DISC-3405 trial in sickle cell disease. DISC-3405 remains an investigational anti-TMPRSS6 monoclonal antibody and is not approved as a therapy in any jurisdiction.