A Phase 1/2, First-in-Human, Open-Label, Dose-Escalation Study of the Safety and Pharmacodynamic Activity of Gene Therapy for Congenital Adrenal Hyperplasia through Administration of an Adeno-associated Virus (AAV) Serotype 5-Based Recombinant Vector Encoding the Human CYP21A2 Gene

This is a study designed to evaluate the safety, tolerability, and efficacy of a one-time gene therapy (BBP-631) for adult patients diagnosed with classic congenital adrenal hyperplasia (CAH). The goal of gene therapy for CAH is to give the body a functioning CYP21A2 gene using a vector (an agent used to deliver a gene into the body). Having a functioning CYP21A2 gene in the adrenal gland may allow the body to naturally produce its own cortisol and aldosterone. The study treatment and follow-up lasts 1 year with a long-term follow-up of 4 more years.