Topical gene therapy for 'butterfly children' under review in EU

The European Medical Agency (EMA) has recommended marketing authorisation in the EU for a topical gene therapy drug to treat a rare genetic skin condition in children.

The drug, Vyjuvek, offers treatment for dystrophic epidermolysis bullosa (DEB), a rare genetic condition that can leave children with delicate, blistering skin. The application was submitted by Krystal Biotech Netherlands, an international branch of Krystal Biotech, headquartered in Pennsylvania, and reviewed by the EMA's Committee for Medicinal Products for Human Use (CHMP). The FDA approved Vyjuvek for use in the USA in May 2023 (see BioNews 1191). Clinical trials found that the benefits from the drug outweighed side effects felt by patients, and use of the drug in the USA provided additional safety data for the EU.

'The CHMP's recommendation for approval of Vyjuvek is an exciting step towards our goal of delivering the first ever corrective therapy to DEB patients across Europe,' said Suma Krishnan, president of Research and Development at Krystal Biotech. 'The CHMP's support for a broad label, including treatment of patients from birth and the option of patient or caregiver administration at home, are also fantastic outcomes for the DEB patients we aim to serve, broadening access and reducing barriers to starting on and staying on therapy.'

DEB is a genetic skin condition caused by a mutation in the collagen gene COL7A1. Skin layers are connected through collagen proteins, some of which are manufactured by COL7A1. When the gene is mutated, collagen proteins are either misshapen or missing. This causes weakness between the skin layers, allowing them to rub together, forming blisters and other wounds.

Recessive DEB is the most severe form of the condition, and symptoms can include severe scarring, joint deformities, loss of vision and aggressive skin cancer. DEB is usually present at birth, and the delicate nature of the skin gives children with the condition the name 'butterfly children'.

Most DEB patients seek supportive care for their symptoms as existing treatments do not address the cause of the blisters. Gene therapy drugs aim to shift this paradigm by delivering functional copies of COL7A1 to the body through a modified herpes virus. Vyjuvek works by delivering gene therapy as a topical gel applied directly to open wounds. The drug was found to accelerate the wound healing process compared to a placebo.

The application was supported by the EMA's priority medicines scheme which offers early support for medicines addressing unmet medical needs. The EMA recommended approval for the drug to treat patients of all ages, including infants.

'We are very pleased that our patients, from birth, will have a simple, topical treatment that promotes durable wound closure, something that until now has been beyond the reach of any therapy,' said Professor Christine Bodemer, head of the Department of Dermatology at the Necker Enfants Malades Hospital in Paris, France. 'This is a remarkable advance for DEB patients and a new approach to gene therapy for genodermatoses, revolutionary and remarkably innovative.'

A final decision on the drug's approval is expected in the second quarter of 2025.

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The availability of genetic and genomic testing for people and families affected by rare disease will be discussed at the free-to-attend online event Rare Disease Genomic Testing: How Do We Make Access Equitable and Timely?, taking place online on Wednesday 18 June 2025.

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