BALLERUP, Denmark — September 18, 2026

LEO Pharma announced that the U.S. Food and Drug Administration (FDA) has accepted the New Drug Application (NDA) for dersimelagon and granted Priority Review, with a Prescription Drug User Fee Act (PDUFA) action date expected by the end of February 2027. Dersimelagon is an investigational, once-daily oral melanocortin 1 receptor (MC1R) agonist being developed for erythropoietic protoporphyria (EPP) and X-linked protoporphyria (XLP), rare genetic disorders associated with severe sunlight-induced pain. The regulatory milestone follows LEO Pharma’s completion of its acquisition of worldwide rights to dersimelagon from Tanabe Pharma.

Dersimelagon Targets Rare Sunlight-Induced Skin Disorders

Dersimelagon is a once-daily oral small-molecule MC1R agonist designed for patients with EPP and XLP, two lifelong genetic disorders that can cause intense pain and other symptoms following exposure to sunlight. Patients may experience rash, swelling, redness and burning sensations, while some can develop liver complications. Earlier in 2026, Tanabe Pharma reported results from the Phase 3 INSPIRE study, a randomized, double-blind, placebo-controlled trial that demonstrated statistically significant and clinically meaningful outcomes across primary and secondary endpoints. The study included a significant increase in average daily sunlight exposure time before the onset of first prodromal symptoms..

LEO Completes Acquisition of Dersimelagon From Tanabe

LEO Pharma has completed the acquisition of worldwide rights to dersimelagon from Tanabe Pharma, combining Tanabe’s development program with LEO Pharma’s dermatology expertise and global commercial infrastructure. The transaction includes up to $435 million in upfront and near-term milestone payments, along with potential downstream milestones and tiered royalties ranging from double-digit percentages to the mid-teens on net sales. The acquisition strengthens LEO Pharma’s late-stage rare dermatology pipeline and complements its broader innovation activities, including its HSV gene therapy platform acquisition from Replay and its partnership with Boehringer Ingelheim for Spevigo®.

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FDA Decision Could Come by February 2027

The Priority Review designation establishes an FDA action date by the end of February 2027, bringing dersimelagon toward a potential U.S. regulatory decision. If approved, LEO Pharma said dersimelagon could become the first oral treatment for EPP and XLP, providing a potential new treatment option for patients whose disease can substantially restrict outdoor activity and daily life. However, dersimelagon remains investigational, and its safety and efficacy have not been established by the FDA or any other regulatory authority. The company said the transaction does not change its 2026 financial outlook, which already incorporated the acquisition.

Source:LEO Pharma, press release