For patients with polycythemia vera (PV), frequent phlebotomies and cytoreductive therapies are the norm — and they come at a real cost to quality of life. A new monoclonal antibody, DISC-3405, could change that. Presented at the Society of Hematologic Oncology 2026 Annual Meeting, phase 2 data from the RESTORE-PV trial show the drug significantly reduces the need for blood draws while keeping hematocrit levels in check.

DISC-3405 works by targeting TMPRSS6, a protein that regulates iron metabolism. By inhibiting it, the drug raises hepcidin levels, which restricts iron availability and curbs the excessive red blood cell production that defines PV. The trial enrolled 40 adults across two dosing cohorts, with results available primarily from cohort A (every-2-week dosing after a step-up period).

By the Numbers:

• Mean phlebotomy events dropped from 4 to 0.6 over 26 weeks in cohort A
• 61.5% of patients who completed 26 weeks remained phlebotomy-free
• 77.8% of patients who completed 32 weeks remained phlebotomy-free
• 82.4% of adverse events were grade 1 (mild)
• Only 5.3% of patients experienced serious adverse events, none treatment-related

Why it matters: DISC-3405 is the first TMPRSS6-targeting monoclonal antibody to demonstrate phlebotomy reduction in PV, offering a potentially gentler, more sustainable treatment path for patients who currently face a lifetime of invasive procedures.