EX-99.1 2 rgnx-ex99_1.htm EX-99.1 EX-99.1 EXHIBIT 99.1 REGENXBIO Announces Regulatory Update on RGX-121 for MPS II ROCKVILLE, Md., August 24, 2026 - REGENXBIO Inc. (Nasdaq: RGNX) today provided an update on its investigational gene therapy, RGX-121 (clemidsogene lanparvovec), for the treatment of Mucopolysaccharidosis type II (MPS II), also known as Hunter Syndrome. The U.S. Food and Drug Administration (FDA) placed a clinical hold on RGX-121 following the discovery of asymptomatic spine MRI findings in five participants in the CAMPSIITE® study; REGENXBIO does not expect to resubmit the RGX-121 Biologics License Application (BLA) in the near term. “We believe these findings are unique and limited to our Hunter Syndrome program, and require longer-term follow-up and additional data analysis to assess the benefit-risk profile of RGX-121,” said Curran Simpson, President and CEO of REGENXBIO. “We remain focused on our Duchenne and retinal disease candidates, which utilize a different capsid and routes of administration, with near-term catalysts that are on track, including the planned submission of the Duchenne BLA this quarter and the wet AMD topline pivotal data announcement …
Open exhibit ↗Current Report · Items 7.01, 8.01, 9.01 · 8-K
REGENXBIO Inc.
RGNXNASDAQEQUITYCurrent
Regulation FD Disclosure · Other Events
Item 7.01 Regulation FD Disclosure. On August 24, 2026, REGENXBIO Inc. (the “Company”) announced that it received communication from the U.S. Food and Drug Administration (“FDA”) that the Company’s Investigational New Drug application for its Phase I/II/III trial of RGX-121 for Mucopolysaccharidosis type II (“MPS II”), also known as Hunter Syndrome, was placed on clinical hold and that the Company…
Company context
REGENXBIO is a biotechnology company on a mission to improve lives through the curative potential of gene therapy. Since its founding in 2009, REGENXBIO has pioneered the field of AAV gene therapy. REGENXBIO is advancing a late-stage pipeline of one-time treatments for rare and retinal diseases, including RGX-202 for the treatment of Duchenne; surabgene lomparvovec (ABBV-RGX-314) for the treatment of wet AMD and diabetic retinopathy, in collaboration with AbbVie, and NAVSUNLI™ (clemidsogene lanparvovec-sngl, RGX-121) for the treatment of MPS II and RGX-111 for the treatment of MPS I, both in partnership with Nippon Shinyaku. Thousands of patients have been treated with REGENXBIO's AAV platform, including those receiving Novartis' ZOLGENSMA®. REGENXBIO's investigational gene therapies have the potential to change the way healthcare is delivered for millions of people. For more information, please visit www. REGENXBIO.com.