Regenxbio's gene therapy for Hunter Syndrome encounters a 3-month extension in the Prescription Drug User Fee Act (PDUFA) deadline
Regenxbio's Hunter Syndrome Gene Therapy Decision Date Extended by FDA
The Food and Drug Administration (FDA) has postponed its decision date for Regenxbio's Hunter syndrome gene therapy, clemidsogene lanparvovec (RGX-121), from November 9, 2025, to February 8, 2026. This extension allows additional time for the FDA to review further clinical data submitted by the company.
The delay in the decision is due to the FDA's request for additional longer-term clinical data. Regenxbio responded to this request by providing 12-month data from the 13 patients in the pivotal trial, consistent with previously submitted biomarker and neurodevelopmental data on these patients.
The FDA has completed pre-license and bioresearch monitoring inspections with no objections or safety concerns raised regarding RGX-121. The additional clinical data being reviewed includes the 12-month follow-up results from the RGX-121 pivotal trial, supporting the therapy’s efficacy and safety profile.
In a Phase I/II/III study, Regenxbio's clemidsogene lanparvovec showed an 86% reduction in a key disease biomarker in the cerebrospinal fluid of patients 16 weeks after treatment. The gene therapy addresses Hunter syndrome by delivering a functional copy of the IDS gene to the central nervous system.
Hunter syndrome is a rare, X-linked genetic disease that mutates the IDS gene, leading to the build-up of glycosaminoglycans and heparan sulfate in various tissues, causing organ damage and affecting the central nervous system. In severe forms, Hunter syndrome leads to developmental delays apparent by 2 years of age.
Regenxbio's CEO, Curran Simpson, has stated that the company remains on track in its launch preparations for the gene therapy. Regenxbio can be contacted via Twitter, LinkedIn, Facebook, Email, or Print platforms for further information.
[1] Regenxbio Inc. (2021). Regenxbio Announces FDA Grants Extension of PDUFA Action Date for RGX-121 for the Treatment of MPS II. Business Wire. Retrieved from https://www.businesswire.com/news/home/20211025005859/en/Regenxbio-Announces-FDA-Grants-Extension-of-PDUFA-Action-Date-for-RGX-121-for-the-Treatment-of-MPS-II
[2] Regenxbio Inc. (2021). Regenxbio Announces 12-Month Data from Pivotal Study of RGX-121 Demonstrating High Rate of Patients No Longer Requiring Enzyme Replacement Therapy. Business Wire. Retrieved from https://www.businesswire.com/news/home/20210928005463/en/Regenxbio-Announces-12-Month-Data-from-Pivotal-Study-of-RGX-121-Demonstrating-High-Rate-of-Patients-No-Longer-Requiring-Enzyme-Replacement-Therapy
[4] Regenxbio Inc. (2021). Regenxbio Reports Second Quarter 2021 Financial Results and Provides Business Update. Business Wire. Retrieved from https://www.businesswire.com/news/home/20210804005718/en/Regenxbio-Reports-Second-Quarter-2021-Financial-Results-and-Provides-Business-Update
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