FDA Awards Platform Technology Designation to Krystal Biotech, Validating HSV-1 Vector Platform

The U.S. Food and Drug Administration (FDA) has granted its second platform technology designation to Krystal Biotech for the company's non-replicating HSV-1 viral vector, used in the delivery of its gene therapies. This development comes after the FDA revoked Sarepta Therapeutics' platform designation in July, following a series of deaths linked to their adeno-associated virus vector platform.

Krystal Biotech's HSV-1 Technology

Krystal's HSV-1 technology utilizes a replication-deficient version of the herpes simplex virus type 1. The vector capitalizes on HSV-1's natural characteristics, including a high payload capacity and ability to evade the immune system, with the aim of minimizing toxicities. This platform has already been successfully employed in Krystal's only approved product, Vyjuvek, a topical gel for treating wounds in patients with dystrophic epidermolysis bullosa, which received FDA approval in 2023.

Implications of the Platform Technology Designation

The FDA's platform technology designation is awarded to companies that use a "well-understood and reproducible technology" as an essential part of their drugs. This designation is intended to streamline drug development and regulatory review processes for products utilizing the designated technology.

William Blair analysts noted, "We view the FDA's platform technology designation as validating Krystal's HSV-1 vector platform and cross-program utility." The designation allows Krystal to leverage manufacturing and nonclinical safety data from previous products using the same technology in future FDA submissions, potentially accelerating the development of new therapies.

Future Applications and Development

Krystal Biotech plans to leverage this designation for its redosable eye drop gene therapy KB801, currently in Phase I/II development for neurotropic keratitis, a rare corneal disease leading to eye injuries. The fact that the FDA granted the platform designation despite the different administration methods between Vyjuvek (topical gel) and KB801 (eye drop) suggests that the agency views Krystal's HSV-1 vector as likely having reproducible efficacy across various administration methodologies.

This development positions Krystal Biotech as "poised to be the first major beneficiary" of the FDA's platform designation program, according to William Blair analysts, potentially opening doors for expedited development of future gene therapies using their HSV-1 vector technology.