LEO Pharma agreed to license worldwide rights to Tanabe Pharma’s late-stage oral drug dersimelagon for erythropoietic protoporphyria and X-linked protoporphyria in a deal worth up to $435 million. The transaction includes upfront and near-term payments tied to development and regulatory milestones. Dersimelagon is designed to increase skin melanin production to reduce light penetration and phototoxic reactions in the rare, lifelong genetic skin disorders. The asset completed a Phase 3 trial (NCT05005975), and Tanabe said a US FDA new drug application was submitted in June 2026. LEO Pharma framed the acquisition as an expansion of its rare dermatology pipeline, citing the drug’s Fast Track and Orphan Drug designations. Tanabe characterized the licensing as a path to accelerate access if the therapy is approved.