Filsuvez in Moderate-to-Severe Epidermolysis Bullosa Simplex

Inclusion Criteria: * Subject has a documented diagnosis and confirmed clinical history of EBS. The Investigator will determine subject eligibility based on historical phenotypic presentation of EBS symptoms along with genetic/diagnosis documentation in order to determine EBS severity. * The following skin conditions are required: * A minimum area of \~3% BSA containing active blisters/erosions, and freshly ruptured blisters across 50% of the TLA (as assessed by the PI). Skin erosions, keratoderma, fissures and/or erythema may also be present. * Subjects will be permitted to treat their feet to assess plantar blister surface area but blistering on the feet is not a requirement for study inclusion. * TLA may not be infected (as assessed by PI) or have been treated with a topical antibiotic within 14 days. * If the subject is a woman of childbearing potential (WOCBP) (Need to verify current labeling on use during pregnancy) * Has a negative urine pregnancy test at baseline. * Agrees to use an approved effective form of birth control with failure rates \<1% per year (e.g., implant, injectable, combined oral contraceptive, intrauterine contraceptive device, sexual abstinence, vasectomized partner) during participation in the study. * Is not nursing. * Subject's laboratory values (blood and urine) are within the range of normal or abnormal values are within normal levels for the disease and in the opinion of the PI the values are not clinically relevant for study pa…