Disc Medicine's Bitopertin Meets Both Primary Goals in Phase 3 Trial

Disc Medicine, Inc.'s bitopertin met both primary goals in a Phase 3 trial for two rare blood disorders, giving the company data it plans to submit for FDA approval.

The Apollo trial enrolled 183 adults and adolescents with erythropoietic protoporphyria or X-linked protoporphyria, conditions that cause painful reactions to light. Compared with placebo, bitopertin produced a 41.4% greater reduction from baseline in whole-blood metal-free protoporphyrin IX, a disease-related blood marker.

During month six, patients receiving bitopertin averaged 12.2 more hours per month in light without pain than those receiving placebo. The trial also met its secondary goals, including fewer light-triggered reactions. Dizziness affected 50% of patients receiving the drug and was generally temporary and mild or moderate.

The FDA issued Disc Medicine a complete response letter on Feb. 13, 2026. Earlier trials had not established a link between changes in the blood marker and measures of sunlight exposure, and the FDA sought Phase 3 results before deciding on approval.

Disc Medicine licensed worldwide rights to bitopertin from Roche in 2021. The company plans to resubmit its application by the end of 2026 and anticipates an FDA decision by mid-2027.