LEO Pharma acquires Replay to advance their gene therapy pipeline for rare genetic skin diseases

DENMARK — LEO Pharma has signed a definitive agreement to acquire Replay, a company specializing in gene therapy treatments for rare genetic skin disorders.

The acquisition marks a major step in LEO Pharma’s strategy to expand its capabilities in advanced dermatological therapies and strengthens its position in the fast-growing field of gene therapy for rare skin diseases.

Through the deal, LEO Pharma will gain access to Replay’s proprietary high-payload herpes simplex virus (HSV) delivery platform, an innovative technology designed to deliver large therapeutic genes directly into skin cells.

This next-generation gene therapy system is expected to significantly enhance LEO Pharma’s pipeline for rare dermatological conditions that currently have limited treatment options.

The transaction will see Replay’s equity holders receive an upfront payment of US$50 million, alongside milestone-based payments and tiered single-digit royalty agreements.

Legal advisers on the acquisition include Latham & Watkins for LEO Pharma, while Replay was represented by Mintz and Levin Cohn Ferris Glovsky and Popeo.

Expanding the potential of gene therapy in dermatology

Gene therapy uses engineered viruses to deliver corrective genetic material into cells, allowing treatment at the root cause of disease rather than simply managing symptoms.

Replay’s platform utilizes genetically modified HSV vectors, which offer a distinct advantage because of their ability to carry large genetic payloads.

This capability makes the platform particularly suitable for rare skin diseases caused by defective or missing genes.

Unlike many traditional gene delivery systems, Replay’s HSV-based therapy is formulated as a topical gel for direct application to affected skin areas, enabling targeted delivery of therapeutic genes.

According to Christophe Bourdon, the acquisition reflects LEO Pharma’s commitment to investing in transformative dermatology technologies.

“Replay’s HSV gene therapy platform offers significant promise for patients living with rare genetic skin diseases, and realizing its full potential requires specialized expertise in medical dermatology,” Bourdon said.

He added that LEO identified Replay through its artificial intelligence-powered scouting platform, Innoviewer, which helps the company identify high-value innovation opportunities.

Bourdon noted that the transaction aligns closely with LEO Pharma’s broader strategy to focus on high-impact opportunities that can reshape treatment standards in dermatology.

Focus on Dystrophic Epidermolysis Bullosa

Replay’s lead drug candidate is currently in preclinical development for Dystrophic Epidermolysis Bullosa (DEB), a rare inherited condition that causes the skin to become extremely fragile.

Patients living with DEB experience painful blistering, chronic wounds, slow healing, and extensive scarring.

In severe cases, repeated skin damage can increase the risk of aggressive skin cancer.

Because DEB comes from specific genetic mutations, researchers consider gene therapy one of the most promising treatment approaches.

Replay’s topical HSV-based platform could potentially address the underlying genetic defect directly in affected skin cells.

Lachlan MacKinnon emphasised the strategic fit between the two companies, noting that Replay’s scientific platform, combined with LEO Pharma’s longstanding expertise and global dermatology infrastructure, could accelerate the development of treatments for patients with urgent unmet medical needs.

Support from the rare disease community

The acquisition has also received support from the rare disease research community.

DEBRA Research, which previously collaborated with Replay and helped facilitate discussions between the companies, welcomed the move.

Its managing director, Martin Steiner, described DEB as one of the most devastating inherited skin disorders and said the combination of Replay’s gene therapy platform with LEO Pharma’s dermatology expertise represents an important development for patients and researchers working toward effective treatments.

Building on broader dermatology expansion

Replay’s specialized gene therapy design and manufacturing team will join LEO Pharma as part of the acquisition, allowing the company to continue advancing the HSV platform while integrating it into its broader dermatology research portfolio.

The deal follows another key regulatory milestone for LEO Pharma.

In December 2025, the company submitted an application to the European Medicines Agency to expand the label for Anzupgo to include adolescents aged 12 to 17 with moderate-to-severe chronic hand eczema across the European Union.