Disc Medicine announced positive Phase 3 APOLLO results for bitopertin in erythropoietic protoporphyria (EPP), with all primary and secondary endpoints met and a planned FDA NDA resubmission by year-end 2026.

APOLLO evaluated bitopertin as an oral GlyT1 inhibitor aimed at modulating heme biosynthesis; the Phase 3 data showed a substantial reduction in whole-blood PPIX and longer, pain-free light exposure, addressing prior FDA concerns.

Analysts described the data as strongly supportive of approval, with peak sales potential around $1.0–1.2 billion and a view that bitopertin could be best-in-class in the EPP space.

The company previously received a Complete Response Letter from the FDA in February 2026, but the new APOLLO results provide a potential path to resubmission and a decision by mid-2027.

Disc intends to resubmit the NDA to the FDA by the end of 2026, targeting a regulatory decision in mid-2027.

Safety in the topline data was acceptable, with dizziness reported in about half of bitopertin recipients (mostly mild or transient) and no treatment-related Grade 4+ adverse events or discontinuations attributed to the drug.

In adults, bitopertin extended time to prodromal symptoms by about 56 minutes versus placebo at six months, with a notable reduction in PPIX and improvements in quality-of-life measures.

Secondary endpoints, including reductions in phototoxic reactions and increases in cumulative light exposure without pain, were met, along with improvements in two QoL measures.

Bitopertin is an investigational oral GlyT1 inhibitor licensed from Roche and being developed by Disc Medicine after global rights were acquired in May 2021.

Disc estimates the US EPP patient population at up to about 20,000, with roughly 14,000 diagnosed aged 12 and older, and plans a PpIX testing program in November.

Leadership and market context contributed to a dramatic one-day stock move, with the broader biotech rally supporting Disc’s phase 3 news.

The company provided context on its background, strategic Roche license rights, and media/investor relations contacts tied to the announcement.