REGENXBIO Inc. Regenxbio Inc is a biotechnology company. Its main activity is the development and commercialization of recombinant adeno associated virus gene therapy to correct an underlying genetic defect. The diseases that the Regenxbio platform targets are metabolic (homozygous familial hypercholesterolemia), neurodegenerative conditions (mucopolysaccharidosis), and retinal diseases (wet age-related macular degeneration, X-linked retinitis pigmentosa). The company derives the majority of its revenue from the United States.