RGX-121 is an investigational one-time AAV9 gene therapy candidate for mucopolysaccharidosis type II (MPS II, Hunter syndrome). The program is intended to deliver iduronate-2-sulfatase gene expression through CNS-directed administration and has been evaluated in Phase I/II studies. As of January 29, 2026, partner disclosures reported an FDA clinical hold on RGX-121.
Biotech companies posted Q2 2026 results: REGENXBIO's Duchenne trial met its primary endpoint, Compass Pathways' COMP360 NDA submission is on track for Q4, Puma raised full-year guidance on NERLYNX demand, and Evotec cut its 2026 outlook.
A securities class action lawsuit alleges REGENXBIO misled investors about the safety of its gene therapy RGX-111. Following an FDA clinical hold due to a patient tumor, the stock fell 17.8% in one day. Affected shareholders have until April 14, 2026 to seek lead plaintiff status.
The FDA has granted accelerated approval to Denali Therapeutics' Avlayah (tividenofusp alfa-eknm), the first therapy targeting neurological symptoms of Hunter syndrome. The approval was based on a surrogate endpoint measuring heparan sulfate reduction in cerebrospinal fluid, with confirmatory study results required for full approval. The global Hunter syndrome treatment market is projected to reach $2.6 billion by 2033.
A class action lawsuit was filed against REGENXBIO covering the period from February 9, 2022 to January 27, 2026, following FDA clinical holds on gene therapies RGX-111 and RGX-121 after a CNS tumor was discovered in a trial participant.
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The FDA placed clinical holds on Regenxbio's RGX-111 and RGX-121 gene therapies following a tumor case in an MPS I patient. The company's stock fell nearly 18% on the news.
