Shares of biotech company Disc had their best day in four years. Its project has been given a second chance

Shares of mid-cap biotech company Disc Medicine soared nearly 40% on October 19—the largest one-day gain since late 2022. The company announced that, following successful trials, it will resubmit an application to the regulator for approval of its drug to treat a rare genetic disorder that causes acute sensitivity to sunlight. Earlier this year, the regulator refused to approve the drug, stating that it needed more data.

Disc shares rose 39% on the Nasdaq on October 19 to $78.9. This is the largest one-day gain since late 2022, according to Barron’s.

The rally was triggered by the company’s announcement of successful results from the final phase of clinical trials for its drug, bitoperetin. It is intended to treat erythropoietic protoporphyria, a rare inherited disorder in which the accumulation of a toxic substance causes extreme sensitivity to light.

Current treatment standards include measures to avoid sunlight, such as limiting outdoor activity to nighttime, wearing protective clothing, using opaque screens, and using pain relief, according to the press release. Scenesse, a medication that helps extend the amount of time adult patients in the U.S. can spend in the light without pain, has been approved.

A study of bitoperin showed that levels of the toxic substance decreased by nearly 46% in patients who took it, compared with just 4.4% in those in the placebo group. Crucially, by the sixth month of the study, the average amount of time patients taking bitoperthine could spend in the sun without pain was 41.4 hours, compared with 28.9 hours for those taking the placebo, Barron’s notes.

“We couldn’t have hoped for a better result,” said the company’s CEO, John Quisel (his remarks are quoted in the press release). Disc plans to resubmit its application to the FDA for the approval of bitopertein by the end of 2026 and expects a decision from the regulator by mid-2027, according to the press release.

The results obtained address key shortcomings identified by the regulator during Disc’s previous attempt to obtain approval for its product, according to Barron’s.

In the fall of 2025, the biotech company received a National Priority Voucher from the FDA commissioner. It entitles drug developers to reduce the review time for their marketing authorization applications to 1–2 months, instead of the usual 10–12.

However, in February 2026, the FDA denied approval of bitopertein: the regulator deemed the evidence insufficient to show that reducing the level of the toxic substance leads to clinical improvement. This caused Disc’s stock price to plummet 22% in just one day and forced the company to announce a 20% workforce reduction.

After the market closed on October 19, Disc announced plans to raise $350 million through a secondary offering of shares and prepaid warrants. The company intends to use the proceeds for research and development of drugs, as well as to prepare for the potential launch of bitopertein.

Following the announcement of clinical results on October 19, two Wall Street analysts immediately raised their price targets for Disc shares: one from Cantor Fitzgerald—by 36% to $170 (115.5% upside potential), and BMO Capital raised theirs by 20% to $120 (52% upside). Both investment banks maintained their “buy” ratings on the company’s stock. In total, the company’s stock has 13 “buy” recommendations from Wall Street analysts; Disc has no other ratings, according to MarketWatch. The average target price of $121.50 implies a 54% upside potential relative to the closing price on October 19.