FDA Grants Breakthrough Therapy to PTGX’s Rusfertide for Erythrocytosis in Polycythemia Vera; NDA Filing Q4 2025, Quest Diagnostics Receives Breakthrough Device Designation

The U.S. Food and Drug Administration (FDA) has granted Breakthrough Therapy designation to Rusfertide, a treatment developed by PTGX for erythrocytosis in patients with polycythemia vera. This designation complements Rusfertide's existing Orphan Drug and Fast Track designations, providing multiple benefits to its development program. PTGX is on track to file a New Drug Application (NDA) for Rusfertide in the fourth quarter of 2025. Additionally, PTGX will make an opt-in or opt-out decision regarding a collaboration agreement during a 90-day window spanning late 2025 to early 2026, approximately four months after the NDA submission. The opt-out option involves potential milestones totaling $1.375 billion plus worldwide royalties of 14% to 29%, while the opt-in option offers $330 million in potential milestones, 10% to 17% ex-U.S. royalties, and a U.S. profit and loss split, with the decision dependent on net present value considerations. Separately, Quest Diagnostics (DGX) has received FDA Breakthrough Device designation for its Haystack MRD circulating tumor DNA test, a diagnostic tool aimed at detecting minimal residual disease in oncology patients.