LEO Pharma Agrees to Acquire Dersimelagon, Expanding Late-Stage Rare Dermatology Pipeline

LEO Pharma has agreed to acquire worldwide rights to dersimelagon, an investigational once-daily oral melanocortin 1 receptor (MC1R) agonist for erythropoietic protoporphyria (EPP) and X-linked protoporphyria (XLP). The transaction adds an asset that has completed Phase 3 development, with a U.S. New Drug Application (NDA) submitted to the FDA in June 2026 and currently under regulatory review.

The acquisition expands LEO Pharma’s focus on rare dermatology following its recent acquisition of Replay’s next-generation HSV gene therapy platform and its partnership with Boehringer Ingelheim for Spevigo (spesolimab).

Dersimelagon Targets Sunlight-Induced Phototoxicity

EPP and XLP are rare inherited disorders that cause severe photosensitivity. Sunlight exposure can trigger intense skin pain and phototoxic reactions, with symptoms including redness, swelling, rash and burning sensations. Some patients can also develop liver complications.

Dersimelagon activates MC1R and increases melanin in the skin. By increasing melanin, the therapy may reduce sunlight penetration and limit the phototoxic reactions triggered by light exposure.

If approved, dersimelagon would represent the first oral therapy for EPP and XLP, potentially addressing a significant unmet need for patients whose disease can severely restrict outdoor activity and daily life.

Phase 3 INSPIRE Study Supports Regulatory Development

Tanabe Pharma evaluated dersimelagon in the global, randomized, double-blind, placebo-controlled Phase 3 INSPIRE trial (NCT06144840) in patients with EPP and XLP. The company reported statistically significant and clinically meaningful results across the primary and secondary endpoints.

A key functional outcome was a significant prolongation of average daily sunlight exposure time before the onset of first prodromal symptoms. The Phase 3 findings were presented as a late-breaking presentation at the 2026 American Academy of Dermatology Annual Meeting.

Dersimelagon has received both FDA Fast Track and Orphan Drug designations. However, its safety and efficacy have not been established by any regulatory authority, and the FDA has not yet approved the therapy.

Deal Strengthens LEO Pharma’s Rare Dermatology Strategy

Under the agreement, the acquisition includes up to $435 million in upfront and near-term milestone payments, along with potential downstream milestones and tiered royalties on net sales.

LEO Pharma CEO Christophe Bourdon said patients with EPP and XLP face a substantial lifelong burden from sunlight-induced reactions and that dersimelagon represents an opportunity to expand the company’s rare dermatology pipeline with a late-stage oral therapy.

Tanabe Pharma CEO Akihisa Harada said LEO Pharma’s medical dermatology expertise and global reach could help advance dersimelagon toward patients if regulatory approval is secured.

FDA Review Becomes the Next Key Milestone

The transaction remains subject to customary closing conditions, including applicable regulatory approvals. LEO Pharma expects higher investment in pre-launch activities during 2026 and 2027 in preparation for a potential launch.

The transaction will position LEO Pharma to advance the FDA review and prepare for potential commercialization in key markets, including the United States and Japan. The company will also build on its existing dermatology capabilities as it evaluates further opportunities in rare diseases with high unmet need.

Reference

LEO Pharma further strengthens late-stage pipeline with the acquisition of dersimelagon – LEO Pharma