ROCKVILLE, Md., May 13, 2025 /PRNewswire/ — REGENXBIO Inc. (Nasdaq: RGNX) today announced the U.S. Food and Drug Administration (FDA) has accepted for review the Biologics License Application (BLA) seeking accelerated approval for clemidsogene lanparvovec (RGX-121) for the treatment of Mucopolysaccharidosis II (MPS II), also known as Hunter syndrome. The FDA granted the BLA Priority Review with a Prescription Drug User Fee Act (PDUFA) target action date of November 9, 2025. "Acceptance of the RGX-121 BLA marks an exciting milestone on our path to bring the MPS II patient community a one-time treatment with the potential to address both the neurodevelopmental and systemic effects of Hunter syndrome," said Curran M. Simpson, President and Chief Executive Officer of REGENXBIO.