Disc Medicine's Bitopertin Cut Whole-Blood PPIX 41.4% Versus Placebo In Phase 3 EPP Trial
The company plans to resubmit its FDA application by the end of 2026 and anticipates an agency decision by mid-2027.
Disc Medicine said its late-stage APOLLO trial of bitopertin in the rare sun-sensitivity disease EPP met both co-primary goals, with whole-blood PPIX down 41.4% versus placebo, according to an 8-K filed Monday. Nasdaq had halted trading in IRON at 6:55 a.m. ET under code T1, meaning news pending.
What the trial showed
The trial enrolled 183 patients aged 12 or older with EPP or XLP, a related condition, across the US, Canada, Europe and Australia. They were randomized 1:1 to 60 mg of oral bitopertin or placebo once daily for six months, the company said.
The two co-primary endpoints, or main goals, both reached statistical significance. PPIX, the toxic compound that builds up in the disease, fell 41.4% versus placebo (p<0.0001). Average monthly time in light without pain during month 6 rose 12.2 hours versus placebo (p=0.0010).
All secondary endpoints were also significant, the company said. The presentation puts the reduction in the incidence rate of phototoxic reactions at 71% versus placebo, and time to prodrome, the early warning of a reaction, rose 56 minutes in adults. Patient-reported change and severity scores each reached p<0.0001.
Safety and next steps
Dizziness was the most common adverse event: 45 of 91 bitopertin patients (50%) versus 10 of 92 on placebo (11%). The company called it mild or moderate and generally transient. No adverse events exceeded Grade 3, though Grade 3 events occurred in 6 bitopertin patients (7%) versus 3 on placebo (3%). No one in the bitopertin group discontinued the study.
Disc plans to resubmit its New Drug Application to the FDA by the end of 2026, with a decision anticipated by mid-2027. CEO John Quisel said, "We could not have hoped for a better outcome."
The presentation puts predicted genetic prevalence of EPP patients aged 12 and older in the US at about 20,000, with about 14,000 diagnosed. Management held a webcast at 8:00 a.m. ET Monday.
Chief Medical Officer Will Savage said Disc plans to present more detailed APOLLO data at a future medical conference.
