ROCKVILLE, Md. - REGENXBIO Inc. (NASDAQ:RGNX) announced the completion of enrollment for the second cohort in its Phase I/II AFFINITY DUCHENNE® trial of RGX-202, a gene therapy candidate for Duchenne muscular dystrophy (Duchenne). The company also shared promising interim safety and efficacy data, including a significant increase in microdystrophin expression in a young patient.
As of February 6, five patients aged 4.4 to 12.1 years have been treated with RGX-202 without any drug-related serious adverse events. The follow-up period post-administration ranges from about three weeks to over nine months. All patients who reached a three-month follow-up showed a reduction in serum creatinine kinase (CK) levels, suggesting clinical improvement.
Notably, a 6.6-year-old patient exhibited 83.4% of normal microdystrophin expression levels and a 93% reduction in serum CK levels at ten weeks, marking the largest increase observed in the trial to date. This data supports the potential of RGX-202 to produce microdystrophin similar to naturally occurring dystrophin, which is crucial for muscle function.
REGENXBIO plans to determine a pivotal dose by mid-2024 and expects to begin a pivotal trial in the latter half of the year. The company aims to use microdystrophin expression as a surrogate endpoint for a Biologics License Application (BLA) filing through the accelerated approval pathway.
The AFFINITY DUCHENNE trial is designed to evaluate the safety, tolerability, and clinical efficacy of a single intravenous dose of RGX-202 in young Duchenne patients. The trial includes a comprehensive immunosuppression regimen to mitigate potential immunologic responses and will assess various clinical endpoints, including muscle microdystrophin protein levels and functional assessments.
Duchenne is a severe muscle disease affecting approximately 1 in 3,500 to 5,000 boys born each year worldwide. The condition leads to progressive muscle degeneration and premature death. RGX-202 aims to improve muscle resistance to damage by delivering a novel microdystrophin transgene using a proprietary AAV vector and muscle-specific promoter.
REGENXBIO is a leader in gene therapy development, leveraging its NAV Technology Platform to address various therapeutic areas. The company's "5x'25" strategy focuses on advancing five AAV Therapeutics to pivotal-stage or commercial products by 2025.
This news is based on a press release statement from REGENXBIO Inc.
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