The Sponsor is developing KB801, a replication-defective, non-integrating herpes simplex virus type 1 (HSV-1)-derived vector engineered to deliver functional full-length human nerve growth factor (NGF) to the corneas of people with Stage 2 or 3 neurotrophic keratitis (NK) via topical application. This is a Phase 1/2, multicenter, double-masked, placebo-controlled study to evaluate the safety, tolerability, and preliminary efficacy of KB801 in these subjects.