The US Food and Drug Administration (FDA) announced on Friday that it has granted approval to US-based Krystal Biotech, Inc for its Vyjuvek, a herpes-simplex virus type 1 (HSV-1) vector-based gene therapy intended for the treatment of wounds in patients six months of age and older with dystrophic epidermolysis bullosa (DEB) with mutation(s) in the collagen type VII alpha 1 chain (COL7A1) gene.

DEB is a genetic disorder that affects the connective tissue in the skin and nails and results from mutation(s) in the COL7A1 gene

Vyjuvek is a genetically modified (engineered in a laboratory) herpes-simplex virus used to deliver normal copies of the COL7A1 gene to the wounds. It has also been modified to eliminate its ability to replicate in normal cells. Vyjuvek is mixed into an excipient (non-active ingredient) gel prior to topical application.

The safety and effectiveness of Vyjuvek was established primarily in a randomized, double-blinded, placebo-controlled study involving a total of 31 subjects with DEB, including 30 subjects with RDEB and one subject with DDEB. the placebo-treated wound completely closed. In addition, in a different clinical study, two young patients with RDEB (6 and 7 months of age, respectively) received topical Vyjuvek weekly without any new safety findings.