Krystal Biotech, Inc. announced the US Food and Drug Administration (FDA) has granted platform technology designation to the genetically modified, nonreplicating herpes simplex virus type 1 (HSV-1) viral vector used in the company’s redosable eyedrop gene therapy KB801. The therapy is currently under evaluation in a randomized placebo controlled trial for the treatment of neurotrophic keratitis (NK), the company said in a press release. 

KB801 is designed to enable sustained, localized expression and secretion of nerve growth factor (NGF) by epithelial cells in the front of the eye for the treatment of NK. According to the company, recombinant NGF eye drops have been shown to significantly improve corneal healing and are approved for the treatment of NK in multiple jurisdictions worldwide, but rapid clearance from the eye requires intensive administration 6 times a day, limiting therapeutic utility. By enabling the cells of the front of the eye to produce NGF locally, the company said KB801 has the potential to significantly reduce the treatment burden for patients while also maintaining more consistent NGF levels in the front of the eye.

The safety and efficacy of KB801 for the treatment of NK are currently under evaluation in EMERALD-1, the company’s 2:1 randomized, double-masked, multicenter, placebo-controlled phase 1/2 study in patients with NK.