Topical Herpes Virus-Based Gene Therapy Granted FDA Fast Track

Krystal Biotech’s lead candidate has received FDA fast track designation for the treatment of dystrophic epidermolysis bullosa (DEB). The firm is building a GMP facility in Pennsylvania to support future scale-up.

The US Food and Drug Administration (FDA) granted fast track designation to KB103, a topically-applied gene therapy engineered to deliver a human collagen protein to patients suffering from DEB.

The designation will help expedite the development and review process of the allogeneic gene therapy, and is a boost for Pittsburgh, Pennsylvania-based firm Krystal Biotech’s Skin TARgeted Delivery (STAR-D) delivery platform.

STAR-D is based on a modified herpes simplex virus (HSV-1) used to deliver genes to treat skin diseases caused by genetic mutations, Suma Krishnan, founder and chief operating officer of Krystal told BioProcess Insider.

“HSV-1 is naturally well-suited to infecting a variety of skin cells to deliver the missing or mutated gene. Because our modified virus is both non-replicating and non-integrating, we have found that in animal studies to date, the virus helps to deliver the gene without manifesting many of the usual cytotoxic attributes of viral vectors.”

The platform also enables Krystal to formulate its viral product into a gel for a direct and topical way to deliver gene therapies to treat skin diseases directly to the patient, Krishnan added.

“In this aspect we are different than some of our competitors who are pursuing autologous gene therapy approaches to treating skin diseases. Autologous approaches involve harvesting tissue from a patient which is then modified and then delivered back to the same patient. Therefore, autologous approaches tend to be invasive, costly and laborious.”

Manufacturing

Currently a third-party manufacturer makes KB103. The unnamed contract manufacturing organization (CMO) uses Krystal’s proprietary upstream and downstream processes to produce Phase I and II clinical materials.

But the firm is looking to move operations in-house as it looks to scale-up KB103 and its other pipeline products, through the construction of a facility in Pittsburgh.

“This facility should enable us to produce clinical materials for our lead and pipeline products initially and will then be scaled up to produce commercial material in the future,” Krishnan told us.

“This GMP facility will allow us to control of our upstream production process including optimizing our master virus seed stock and maintaining control of our proprietary processes. Developing the GMP facility will also allow us to control our downstream purification process ensuring that we are able to meet all regulatory requirements for commercialization.”

The plant will be operational early 2019, the firm said.