FDA Clinical Hold on RGX-121; BLA Resubmission Not Expected Near Term
RGNX sits 48% above its 52-week low of $5.455 on elevated volume (2.7× avg).
Summary
FDA clinical hold on RGX-121 for Hunter syndrome; REGENXBIO does not expect to resubmit the BLA in the near term after asymptomatic spine MRI findings in five patients.
Key Events · Product Development and Regulatory · RGNX
-
FDA Clinical Hold on RGX-121
FDA placed a clinical hold on the Phase I/II/III trial of RGX-121 for MPS II (Hunter syndrome) after asymptomatic spine MRI findings in five participants in the CAMPSIITE study.
-
BLA Resubmission Delayed Indefinitely
REGENXBIO does not expect to resubmit the RGX-121 Biologics License Application in the near term, effectively pausing the program's regulatory path.
-
MRI Findings Deemed Likely Benign
Investigators deemed the spine MRI findings nonserious and radiologists believe they are likely benign; no brain nodules or masses were identified. All five patients remain clinically stable.
-
Expanded Monitoring Follows RGX-111 Hold
The findings were identified through an expanded MRI monitoring plan implemented a few months ago following the clinical hold related to RGX-111, the company's MPS I program.
Analysis · RGNX · Life Sciences
The FDA placed a clinical hold on REGENXBIO's Hunter syndrome gene therapy RGX-121 after asymptomatic spine MRI findings in five trial participants. The company does not expect to resubmit the BLA in the near term, effectively shelving a program that had been a key part of its rare-disease pipeline. This is a major setback for a company that just reported its first profitable quarter, and it shifts investor focus entirely to the Duchenne and wet AMD programs.
How filings like this one have moved
In the 30 days to Aug 24, 2026, 44% of the 972 measured filings Wiseek scored 9 moved their stock by 5% or more by the next session's close. The median move was -0.11%. These are measured outcomes after filings of this importance, not a forecast for this one.
Measured one observation per ticker per day, after exclusions. Current figures: Filing Impact Tracker · open dataset
At the time of this filing, RGNX was trading at $8.07 on NASDAQ in the Life Sciences sector, with a market capitalization of approximately $531.7M. The 52-week trading range was $5.46 to $16.19. This filing was assessed with negative market sentiment and an importance score of 9 out of 10.