Disc Medicine's late-stage win clears path for approval of sun-allergy pill

By Padmanabhan Ananthan

Oct 19 (Reuters) - Disc Medicine IRON.O said on Monday its experimental pill for a rare disease helped patients spend more time in sunlight without pain, sending its shares surging 35% in early trading.

The late-stage trial success sets the stage for Disc to resubmit its application for an FDA review of bitopertin after the regulator turned down the drug earlier this year. Disc plans to submit the new data by year-end, supporting potential approval and launch around mid-2027.

The FDA had then cited a lack of a clear link between the reduction in patients' protoporphyrin levels and their tolerance to sunlight.

Bitopertin is being developed to treat erythropoietic protoporphyria (EPP), an inherited blood disorder in which a substance called protoporphyrin IX (PPIX) builds up in the blood and makes patients extremely sensitive to sunlight, causing painful skin reactions on exposure.

"We believe the breadth and consistency of the topline findings leave limited residual uncertainty around approvability," Truist analyst Danielle Brill said.

In the trial, which enrolled 183 patients aged 12 and older, those who took bitopertin had 41.4% lower PPIX levels compared to placebo. In the sixth month of treatment, they also gained 12.2 more hours per month of pain-free time in sunlight.

The drug also significantly decreased the number of phototoxic reactions, which are painful skin reactions triggered by light.

"These results mark a significant scientific advancement in EPP ... I expect these results will permanently change the focus of drug development in this field," CEO John Quisel said on a conference call.

Patients with EPP now mainly manage the disease by avoiding sunlight or by using Clinuvel Pharmaceuticals' CUV.AX implant, Scenesse.

BMO analysts estimate peak sales of $1.7 billion for bitopertin and expect early uptake from patients already on therapy through the FDA's expanded access program.