LEO Pharma has agreed to acquire worldwide rights to dersimelagon from Tanabe Pharma for up to $435 million in upfront and near-term milestone payments, adding a late-stage oral rare dermatology candidate to its pipeline. The agreement also provides Tanabe Pharma with potential downstream milestone payments and tiered royalties on net sales.
Dersimelagon is a once-daily oral small MC1R agonist being developed for erythropoietic protoporphyria and X-linked protoporphyria, or EPP and XLP.
The rare genetic conditions can cause severe sunlight-induced skin damage, including burning, redness, swelling and rashes, and can substantially limit patients’ ability to spend time outdoors.
Dersimelagon is designed to increase melanin in the skin to reduce sunlight penetration and protect against phototoxic reactions.
The candidate has received FDA Fast Track and Orphan Drug designations.
Tanabe submitted a New Drug Application to the FDA in June 2026 for treatment of EPP and XLP.
If approved, dersimelagon would become the first oral therapy for the two diseases. It has not yet been approved by the FDA or another regulatory authority.
Tanabe recently reported results from the global Phase 3 INSPIRE study, which showed statistically significant and clinically meaningful outcomes across primary and secondary endpoints.
Those outcomes included a significant increase in average daily sunlight exposure before the onset of prodromal symptoms.
The acquisition expands LEO Pharma’s focus on rare dermatology and follows its 2025 partnership with Boehringer Ingelheim for Spevigo and its acquisition of Replay’s HSV gene therapy platform.
LEO expects the transaction to increase its investment in 2026 for pre-launch activities and in 2027 for a potential product launch.
The transaction remains subject to customary closing conditions and applicable regulatory approvals.
J.P. Morgan Securities acted as financial advisor to LEO Pharma, while Latham & Watkins served as legal advisor.
KEY QUOTES:
“Patients living with EPP or XLP face the devastating lifelong burden of severe reactions to sunlight, and there is a clear need for treatment options that can make a meaningful difference in their everyday lives.”
“By addressing a clear unmet need in a rare skin disease, dersimelagon represents a compelling opportunity to expand our rare dermatology pipeline with a late-stage oral therapy candidate.”
Christophe Bourdon, CEO of LEO Pharma
“EPP and XLP are devastating lifelong diseases that can severely limit patients’ ability to live everyday lives free from sunlight-induced pain, and dersimelagon has the potential to become an important new treatment option.”
“LEO Pharma’s established expertise in medical dermatology and global reach make it the ideal partner to realize the full potential of dersimelagon and, if approved, bring this innovative treatment to patients.”
Akihisa Harada, CEO of Tanabe Pharma
