Krystal Bio grabs first ever FDA nod for a redosable gene therapy

Krystal Biotech announced on Friday that the U.S. FDA approved its topical gene therapy for the repeated treatment of a serious, rare skin disease. 

The approval makes Vyjuvek the first-ever redosable gene therapy and the first and only medicine approved by the FDA for the treatment of dystrophic epidermolysis bullosa (DEB).

According to Pittsburgh-based Krystal, DEB is a serious rare genetic disease that affects the skin and mucosal tissues and is caused by one or more mutations in the COL7A1 gene, resulting in lack of production of functional type VII collagen (COL7) protein. This leads to extremely fragile skin that blisters and tears with minor friction or trauma. Patients suffer from open wounds, which lead to recurrent skin infections, and ultimately increase the risk of developing an aggressive form of skin cancer.

Vyjuvek addresses the genetic cause of DEB by restoring functional copies of the COL7A1 gene to patients. While administration doesn't require as much specialized expertise as traditional gene therapies — according to Krystal it’s "safe and easy to apply directly to wounds" — it still must be administered by a health care professional, either in a health care setting or in the patient's home.

Approval was based on data from a pivotal phase 3 GEM-3 trial, which met its primary endpoint of complete wound healing at six months and its key secondary endpoint of complete wound healing at three months.

With this approval, Krystal was issued a Rare Pediatric Disease Priority Review Voucher.