LEO Pharma to Buy Rights to Tanabe Drug for Rare Skin Diseases for up to $435 Million

Rare Daily Staff

LEO Pharma has agreed to acquire worldwide rights to an experimental once-daily pill from Tanabe Pharma for up to $435 million in upfront and near-term milestone payments. The drug is being developed for two rare genetic disorders that can make ordinary sunlight intensely painful.

The deal also includes potential additional milestones and royalties tied to future sales.

For LEO Pharma, the acquisition is the latest move to build a portfolio focused on rare, high-need dermatologic diseases. The company recently partnered with Boehringer Ingelheim on Spevigo, or spesolimab, and acquired Replay’s next-generation herpes simplex virus gene therapy platform.

Dersimelagon is being developed for erythropoietic protoporphyria, or EPP, and X-linked protoporphyria, known as XLP. People with these lifelong inherited conditions can experience severe skin pain shortly after sun exposure, often accompanied by burning, redness, swelling or rash. The diseases can sharply limit time outdoors, and some patients also face a risk of liver damage.

Dersimelagon is designed to activate the melanocortin 1 receptor, a pathway involved in the production of melanin, the pigment that helps absorb and block ultraviolet light. By increasing melanin in the skin, the treatment is intended to reduce light penetration and protect patients from the painful reactions associated with EPP and XLP.

Tanabe Pharma submitted a New Drug Application to the U.S. Food and Drug Administration in June, and the medicine has received FDA Fast Track and Orphan Drug designations. If approved, LEO Pharma said, it could become the first oral therapy specifically approved for EPP and XLP.

The acquisition follows positive results from the phase 3 INSPIRE trial, a global study comparing dersimelagon with placebo in people with EPP and XLP. According to the companies, the drug met its primary and secondary endpoints and significantly extended the average amount of daily sunlight exposure participants could tolerate before developing early warning symptoms.

Those symptoms can signal the onset of a severe phototoxic reaction. For patients, a longer window before pain begins could translate into greater freedom to carry out routine activities, including commuting, walking outdoors, attending school or working during daylight hours.

“Patients living with EPP or XLP face the devastating lifelong burden of severe reactions to sunlight,” LEO Pharma CEO Christophe Bourdon said in the announcement. He described dersimelagon as an opportunity to add a late-stage oral medicine to the company’s rare-dermatology pipeline.