FDA Grants Fast-Track Designation for Krystal Biotech’s Gene Therapy Candidate KB103 to Treat DEB

The U.S. Food and Drug Administration recently granted fast-track designation to Krystal Biotech’s KB103 for the treatment of dystrophic epidermolysis bullosa (DEB).

DEB is caused by mutations in the COL7A1 gene, the gene that provides instructions to make type VII collagen (COL7). Collagen strengthens body tissues and is important for skin stability. COL7, in particular, keeps the epidermis (the skin’s upper layer) attached to the dermis (its lower layer). Lack of COL7 causes the layers to separate, leading to the development of painful blisters in DEB patients.

KB103 is the first topical gene therapy using Krystal’s STAR-D platform to deliver a normal and functional copy of the COL7A1 gene to skin cells, by way of an engineered herpes simplex virus (HSV-1) modified to not cause the virus.

A fast-track designation means the FDA will expedite both the development and review of the application for approval. It is designed to get new therapies for rare and serious diseases to patients quicker.

“This Fast Track designation represents another positive step for the development of KB103 and is a clear recognition of the serious unmet need that exists for patients suffering from this debilitating disease,” Suma Krishnan, founder and chief operating officer of Krystal, said in a press release.

Earlier this month, Krystal announced that it had dosed the first patient in a Phase 1/2 clinical trial (NCT03536143) assessing the safety and tolerability of KB103 in people with the recessive type of DEB, the most severe form of the disease. The open-label trial is being conducted at Stanford University, and is currently recruiting up to six participants.

KB103’s effectiveness will also be evaluated through wound imaging and analysis of COL7 expression.

In April, Krystal announced that the European Medicines Agency had granted KB103 orphan medicinal product designation (OMPD) for the treatment of DEB. In Europe, OMPD is available to products for the treatment of life-threatening or chronic conditions that affect no more than 5 in 10,000 citizens in the European Union.

The OMPD designation offers Krystal a market exclusivity for 10 years, along with protocol assistance from the EMA, and access to tax and financial incentives.

In January, the U.S. Patent and Trademark Office issued a patent covering Krystal’s HSV vectors and related gene therapies for the treatment of wounds and skin diseases.

Currently, there are no approved treatments for the underlying cause of DEB.