Company: RGNX
Filing Date: 2025-03-13
Form Type: 10-K
Source: 0000950170-25-038770
Chunk: 86

Company: REGENXBIO Inc.
Filing Date: 2025-03-13
Form: 10-K
Item: Item 1
Chunk 86
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 NAVXpress process. In addition to measuring GAGs in the CSF, the trial will continue to collect neurodevelopmental data and caregiver-reported outcomes.

In June 2024, we announced the completion of a successful pre-BLA meeting for RGX-121, where we finalized details of our BLA with FDA. In that announcement, we shared that the FDA continues to be aligned with our plan to use CSF levels of HS D2S6 as a surrogate endpoint reasonably likely to predict clinical benefit to support accelerated approval of RGX-121. We expect an FDA inspection of our Manufacturing Innovation Center following the BLA submission for RGX-121.

In September 2024, we reported long term data showing that patients receiving RGX-121 at the pivotal dose level demonstrated an 85% median reduction of CSF levels of HS D2S6 approaching normal levels and sustained for up to two years. In the dose-finding part of the trial, investigators chose to discontinue standard-of-care intravenous enzyme replacement therapy (ERT) or to remain ERT-naïve for a majority of patients. At the pivotal dose level (dose level 3), 80% of patients were ERT-free at last time point, up to more than 18 months post-dosing. At dose level 2, 71% of patients were ERT-free at last time point, up to almost three years.

In January 2025, we announced a strategic partnership with Nippon Shinyaku to develop and commercialize RGX-121 in the United States and Asia. For more information, refer to "Nippon Shinyaku Partnership for MPS Diseases" below.

In March 2025, we submitted a BLA for RGX-121 seeking accelerated approval to the FDA, which we believe is likely to be eligible for priority review. We expect potential approval of RGX-121 in the second half of 2025. 

Potential approval of the BLA for RGX-121 could result in receipt of a Rare Pediatric Disease Priority Review Voucher in 2025, assuming the statutory criteria are met. If approved, RGX-121 would be the first approved gene therapy and one-time treatment for MPS II.

10

RGX‑111 for the Treatment of MPS I

RGX-111 is our investigational AAV Therapeutic for the treatment of MPS I, a rare disease caused by deficiency of IDUA, an enzyme required for the breakdown of polysaccharides in lysosomes.