REGENXBIO Announces FDA Acceptance and Priority Review of the BLA for RGX-121 for MPS II

Core Viewpoint - REGENXBIO Inc. announced that the FDA has accepted the Biologics License Application (BLA) for RGX-121, a potential one-time gene therapy for Mucopolysaccharidosis II (MPS II), with a target action date of November 9, 2025 [1][7]. Company Overview - REGENXBIO is a biotechnology company focused on gene therapy, founded in 2009, and has developed a late-stage pipeline for rare and retinal diseases [6]. - The company has pioneered AAV gene therapy and aims to improve lives through its curative potential [6]. Product Details - RGX-121 (clemidsogene lanparvovec) is designed to deliver the iduronate-2-sulfatase (IDS) gene to the central nervous system, potentially providing a permanent source of the I2S protein [4]. - The therapy aims to address both neurodevelopmental and systemic effects of Hunter syndrome, which currently relies on weekly enzyme replacement therapy [2]. Regulatory Designations - RGX-121 has received multiple designations from the FDA, including Orphan Drug Product, Rare Pediatric Disease, Fast Track, and Regenerative Medicine Advanced Therapy (RMAT) [2]. Commercialization Strategy - Following potential FDA approval, RGX-121 will be commercialized by NS Pharma, a subsidiary of Nippon Shinyaku, while REGENXBIO retains all rights and proceeds related to the potential sale of a Priority Review Voucher (PRV) [3].