Under the Radar: Disc Shares Jump as Pill for Sunlight Disorder Succeeds in Study -- WSJ

By Lizzy Lawrence and Xavier Martinez

Shares of Disc Medicine rose around 37% on Monday after it announced that its experimental pill succeeded in easing symptoms in people with a rare disease that makes sunlight painful.

Patients with the disease, called erythropoietic protoporphyria, accumulate a compound in their blood that reacts to sunlight and causes searing pain and blistering. In late stage trials, Disc's bitopertin reduced that compound, PPIX, by around 40% and increased the amount of time patients could spend in sunlight without pain by 12 hours a month.

In February, the Food and Drug Administration rejected the drug due to uncertainties about whether a reduction of the blood compound would meaningfully improve symptoms of the disease. It was one of the first drugs to attempt approval through a new, hyper sped-up review program spearheaded by former FDA Commissioner Marty Makary.

Analysts expect Disc to resubmit its drug for approval and foresee between $1 billion to $2 billion in peak sales if it receives that approval.

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October 19, 2026 12:22 ET (16:22 GMT)