LEO Pharma bolsters rare skin disease focus through acquisition of Replay gene therapy platform

• Acquisition adds high-payload herpes simplex virus (HSV) gene therapy targeting genetic skin dis-eases to LEO Pharma’s pipeline and further expands the company’s presence in rare dermatology

• Combines LEO Pharma’s six decades of dermatology expertise with Replay’s next-generation gene therapy platform to advance innovation for patients with rare skin diseases

• The lead program targets dystrophic epidermolysis bullosa (DEB), a devastating genetic skin dis-ease with significant unmet medical need.

Ballerup, Denmark, April 30, 2026 – LEO Pharma, a global leader in medical dermatology delivering innovative solutions for skin health, announces that it has entered into a definitive agreement to acquire Replay, a gene therapy company focused on developing transformative treatments for rare genetic dermatological conditions. The acquisition adds deep expertise and a next-generation gene therapy plat-form to LEO Pharma’s pipeline through Replay’s high-payload herpes simplex virus (HSV) delivery vector.

Viral gene therapy uses engineered viruses to deliver therapeutic genetic material into cells to treat dis-ease at its source. Replay’s gene therapy platform leverages HSV’s unique capacity to deliver large genes, making it particularly well suited for addressing rare, genetically driven dermatological conditions. The genetically modified HSV therapy is formulated as a topical gel that targets the deficient gene when ap-plied directly to the skin.

“Replay’s HSV gene therapy platform holds significant promise for patients with rare genetic skin dis-eases, and realizing its full potential requires focused expertise in medical dermatology - an area where LEO Pharma brings decades of leadership, scale and proven execution,” said Christophe Bourdon, CEO, LEO Pharma. “Using our unique AI-powered scouting platform, Innoviewer™, we identified Replay as a high-potential opportunity. The acquisition aligns with our strategy of investing in the most impactful opportunities in dermatology and positions LEO Pharma at the forefront of next-generation gene therapy.”

“Replay has developed an HSV gene therapy platform with a focus on genetic skin diseases. Natural tropism for skin cells and the ability to redose patients make HSV uniquely suited to treating rare genetic dermatological conditions. Together with LEO Pharma’s decades of dermatology leadership and global infrastructure, purpose-built for skin diseases, we can bring therapies to the patients who need them most and build an enduring dermatology franchise in rare genetic medicine,” said Lachlan MacKinnon, CEO, Replay.

lead drug candidate in Replay’s pipeline is currently in preclinical studies for the treatment of a rare genetic condition called dystrophic epidermolysis bullosa (DEB). This condition causes the skin to be fragile and blister easily, leading to painful chronic wounds that heal slowly and poorly, often resulting in scar tissue and skin cancer.

"Dystrophic epidermolysis bullosa remains one of the most devastating genetic skin diseases with significant unmet need. Pairing Replay's HSV gene therapy platform with LEO Pharma's dermatology expertise and global infrastructure is exactly the kind of combination the DEB community needs. We welcome LEO Pharma's commitment to rare disease and look forward to seeing this platform advance,” said Martin Steiner, Managing Director at DEBRA Research, a non-profit organization dedicated to advancing effective treatments and cures for DEB, which has previously worked with Replay, connected the two companies, and helped LEO Pharma better understand DEB patient needs and treatment opportunities.

LEO Pharma will leverage Replay’s world-class HSV design and manufacturing specialist team to drive continued innovation and program advancement as it joins its dermatology portfolio. Replay’s equity holders will receive USD 50 million upfront, plus milestone payments and tiered single-digit royalties.

Latham & Watkins LLP is acting as LEO Pharma’s legal advisor for the transaction.

Mintz, Levin, Cohn, Ferris, Glovsky and Popeo, P.C. is acting as Replay’s legal advisor for the transaction.