IRON · Disc Medicine, Inc.

Summary

Disc Medicine, Inc. received a Complete Response Letter from the FDA on February 13, 2026, for its NDA for bitopertin in erythropoietic protoporphyria, citing insufficient evidence linking PPIX biomarker to clinical endpoints and requiring APOLLO Phase 3 study results. The company plans to complete APOLLO enrollment by March 2026 with topline data in Q4 2026 to support CRL response.

Key takeaways

• FDA issued CRL on February 13, 2026, for bitopertin NDA due to PPIX surrogate biomarker concerns
• FDA requires APOLLO Phase 3 results before approval decision
• APOLLO trial closing enrollment in March 2026; topline data expected Q4 2026
• APOLLO: ~150 patients, 1:1 randomized, double-blind, placebo-controlled, 60 mg dose, 6-month treatment
• Co-primary endpoints: average monthly time in sunlight without pain (month 6), percent change in whole blood metal-free PPIX (6 months)
• Plans Type A meeting with FDA and CRL response submission in late 2026; potential decision mid-2027