A Study Comparing KB803 and Matched Placebo in Patients With Dystrophic Epidermolysis Bullosa

Subjects participating in the Sponsor's natural history study (protocol NHS) for at least 12 weeks and that meet all other eligibility criteria will be randomized 1:1 to receive ophthalmic administration of B-VEC three times a week or placebo three times a week for the first 12 week intervention period. During the second 12-week intervention period subjects will be crossed-over to receive the alternative Investigational Product (IP) for an additional 12 weeks. IP will be administered in the home setting by a trained designee. The Investigator (or designee) will contact subjects (or their parent/legal guardian) to assess for any adverse events or changes in medications, treatments, or procedures. Subjects (or their parent/legal guardian) will complete weekly symptom diaries and monthly questionnaires to document corneal abrasion symptoms and frequency and gauge overall subject (or parent/legal guardian) impressions of disease severity and disease/symptom changes during the study.