Disc Medicine reports successful Phase 3 trial for EPP drug

Disc Medicine has announced positive topline results from its Phase 3 APOLLO trial evaluating bitopertin, an oral treatment for erythropoietic protoporphyria (EPP) and X-linked protoporphyria (XLP). The study met both co-primary endpoints: a 41.4% reduction in whole-blood metal-free protoporphyrin IX (PPIX) compared to placebo, and an average increase of 12.2 hours of pain-free time in light per month.

These results address previous concerns from the FDA, which had issued a complete response letter in February 2026 because earlier data failed to sufficiently link PPIX reduction to clinical improvements in light tolerance. The APOLLO trial involved 183 patients aged 12 and older across the United States, Canada, Europe, and Australia.

Following this success, Disc Medicine plans to resubmit its New Drug Application (NDA) to the FDA by the end of 2026, with a regulatory decision expected by mid-2027. If approved, the once-daily oral medication could challenge the current market monopoly held by Clinuvel Pharmaceuticals’ Cinere, which requires subcutaneous injections every two months.