BALLERUP, DENMARK, August 18, 2026

LEO Pharma has entered into an agreement to acquire worldwide rights to dersimelagon from Tanabe Pharma, strengthening its late-stage pipeline in rare dermatology. Dersimelagon is an investigational, once-daily oral melanocortin 1 receptor (MC1R) agonist being developed for erythropoietic protoporphyria (EPP) and X-linked protoporphyria (XLP), two rare genetic disorders that can cause severe sunlight-induced pain and skin reactions. The candidate has completed Phase 3 development, and a New Drug Application (NDA) was submitted to the U.S. Food and Drug Administration (FDA) in June 2026. The transaction gives LEO Pharma an opportunity to expand its medical dermatology portfolio with a late-stage therapy addressing a significant unmet medical need.

LEO Pharma Expands Rare Dermatology Pipeline

Under the agreement, LEO Pharma will acquire worldwide rights to dersimelagon from Tanabe Pharma for up to $435 million in upfront and near-term milestone payments, along with potential downstream milestones and tiered royalties based on net sales. The acquisition is part of LEO Pharma’s broader strategy of strengthening its dermatology portfolio through targeted acquisitions, partnerships and external innovation. The company has identified rare skin diseases as an important growth area and is building on previous strategic activities, including its partnership with Boehringer Ingelheim for Spevigo® and its acquisition of Replay’s next-generation HSV gene therapy platform. The transaction remains subject to customary closing conditions, including applicable regulatory approvals.

Dersimelagon Advances After Positive Phase 3 Results

Dersimelagon is designed to activate MC1R, increasing melanin production in the skin and potentially reducing the penetration of sunlight that triggers painful phototoxic reactions in people with EPP and XLP. These inherited disorders can cause severe sunlight-induced skin pain, rash, swelling, redness and burning sensations, while some patients may also experience liver complications. Earlier in 2026, Tanabe Pharma reported positive results from the global, randomized, double-blind, placebo-controlled Phase 3 INSPIRE study, which evaluated dersimelagon in patients with EPP and XLP. The study demonstrated statistically significant and clinically meaningful results across primary and secondary endpoints, including an increase in average daily sunlight exposure time before patients experienced their first prodromal symptoms. The Phase 3 findings were subsequently presented as a late-breaking presentation at the 2026 American Academy of Dermatology Annual Meeting. These data provide the clinical foundation for the candidate’s ongoing regulatory review.

Advertisement

cGxPJobs Banner

FDA Review Could Support First Oral Treatment Option

Dersimelagon has received both FDA Fast Track Designation and Orphan Drug Designation, reflecting the potential importance of the therapy for patients with rare diseases and significant unmet medical needs. The NDA submitted in June 2026 remains under FDA review, and dersimelagon has not been approved by the FDA or any other regulatory authority. Its safety and efficacy therefore remain unestablished by regulators. If approved, dersimelagon could become the first oral therapy for EPP and XLP, potentially offering patients a new treatment approach for managing sunlight-induced symptoms. LEO Pharma expects the acquisition to increase investment in pre-launch activities during 2026 and potentially support a launch in 2027, subject to regulatory approval. By adding a late-stage oral candidate with completed Phase 3 development to its pipeline, LEO Pharma is positioning itself to expand treatment options in rare dermatology while leveraging its long-standing expertise in medical dermatology and global commercial capabilities.

Source: LEO Pharma press relese