REGENXBIO's RGX-202 shows positive interim data in Duchenne muscular dystrophy gene therapy trial

REGENXBIO Inc., a Rockville, Maryland-based gene therapy company, [announced](https://www.prnewswire.com/news-releases/regenxbio-reports-new-positive-interim-data-from-phase-iii-affinity-duchenne-trial-of-rgx-202-302711193.html) new interim data from the Phase I/II AFFINITY DUCHENNE trial of RGX-202 in patients with Duchenne muscular dystrophy. The data, presented at the Muscular Dystrophy Association Clinical and Scientific Conference, showed that participants receiving the pivotal dose exceeded external controls across functional measures at one year, according to the company. ## Trial specifics The AFFINITY DUCHENNE trial is a Phase I/II study evaluating RGX-202 as a gene therapy for Duchenne muscular dystrophy. The company did not disclose the ClinicalTrials.gov identifier, total enrollment, randomization scheme, or specific comparator arm details in the topline release. According to the interim data, participants receiving the pivotal dose demonstrated functional outcomes exceeding external controls at one year, including among participants aged eight and older. The company also reported cardiac MRI data for pivotal dose patients, though specific numerical values for cardiac endpoints were not disclosed. Safety, biomarker, and additional functional data were presented at the conference, but the company did not provide detailed adverse event rates, statistical significance values, or p-values in its announcement. The trial appears to rely on external control comparisons rather than a randomized placebo-controlled design, though the company did not confirm this. The dosing regimen and duration of follow-up beyond one year were not specified in the available materials. REGENXBIO did not disclose specific regulatory filing timelines or planned interactions with the US FDA in the announcement. The company described RGX-202 as a gene therapy candidate for Duchenne muscular dystrophy, and the presentation of data at the MDA conference suggests the program remains in active clinical development. The company did not state whether a pivotal trial or registrational study is planned, nor did it indicate whether the current Phase I/II data would support a regulatory submission. No existing approvals for RGX-202 were referenced. ## Research context RGX-202 is a gene therapy designed to deliver a functional gene construct intended to produce a form of dystrophin, the protein that is absent or deficient in patients with Duchenne muscular dystrophy. Duchenne is caused by mutations in the DMD gene, which encodes dystrophin, a structural protein that stabilizes muscle cell membranes during contraction. Without functional dystrophin, muscle fibers undergo progressive damage, leading to loss of ambulation and cardiorespiratory decline. Gene therapies for Duchenne typically deliver a truncated version of the dystrophin gene, known as micro-dystrophin, using adeno-associated virus vectors. The company did not specify the vector serotype or transgene design for RGX-202 in the available materials. The treatment landscape for Duchenne muscular dystrophy includes corticosteroids as long-standing standard of care, along with several targeted therapies. Key competitors include: - Sarepta Therapeutics' [delandistrogene moxeparvovec](https://www.fda.gov/vaccines-blood-biologics/tissue-tissue-products/elevidys) (Elevidys), an AAV-based micro-dystrophin gene therapy that received accelerated approval from the US FDA in 2023 for ambulatory Duchenne patients aged four and five, later expanded to include broader age groups - Sarepta Therapeutics' [eteplirsen](https://www.accessdata.fda.gov/drugsatfda_docs/nda/2016/206488Orig1s000TOC.cfm) (Exondys 51), an exon-skipping antisense oligonucleotide approved by the US FDA in 2016 for patients with a confirmed mutation amenable to exon 51 skipping - NS Pharma's [viltolarsen](https://www.accessdata.fda.gov/drugsatfda_docs/nda/2020/212154Orig1s000TOC.cfm) (Viltepso), an exon 53 skipping therapy approved by the US FDA in 2020 The interim data from the AFFINITY DUCHENNE trial position RGX-202 within a competitive field where Sarepta's Elevidys holds the only approved gene therapy. Whether RGX-202 can differentiate on durability, cardiac outcomes, or efficacy in older patients remains to be determined by further data disclosure and peer-reviewed analysis. --- Spot something wrong? [Report an issue with this article](https://newsgen-prod.reframedata.com/feedback/rgx-202-duchenne-regenxbios-shows-positive)