REGENXBIO Reports Promising Preclinical Results for RGX-202 Gene Therapy for Duchenne Muscular Dystrophy

REGENXBIO has published promising preclinical results for its RGX-202 gene therapy for Duchenne Muscular Dystrophy. The novel microdystrophin construct containing the C-terminal domain showed superior efficacy compared to versions lacking this domain. The company plans to submit a Biologics License Application by mid-2026, leveraging the accelerated approval pathway. RGX-202's differentiated approach, by including the CT domain, marks a significant advancement for DMD patients, potentially offering functional improvements in the DMD therapeutic landscape.

REGENXBIO Inc. has published promising preclinical results for its RGX-202 gene therapy, which aims to treat Duchenne Muscular Dystrophy (DMD). The results, published in the peer-reviewed journal Molecular Therapy Methods and Clinical Development, demonstrated that a novel microdystrophin construct containing the C-terminal (CT) domain showed superior efficacy compared to versions lacking this domain [1].

The study compared two microdystrophin gene therapy constructs: one including the CT domain and another without it. The microdystrophin with the CT domain exhibited higher levels of protein accumulation, increased muscle force, and improved resistance to damage in mice lacking dystrophin. These findings suggest that the CT domain enhances the microdystrophin design, allowing for higher levels of microdystrophin to accumulate in muscle tissue [2].

The preclinical results support the positive functional data seen in the Phase I/II AFFINITY DUCHENNE® trial of RGX-202, which reported consistent evidence of positively changing the disease trajectory of patients with Duchenne and a favorable safety profile in June 2025 [1]. REGENXBIO is currently enrolling participants in the pivotal portion of the Phase I/II/III AFFINITY DUCHENNE trial of RGX-202 and expects to submit a Biologics License Application (BLA) using the accelerated approval pathway by mid-2026 [1].

RGX-202 is the only investigational or approved microdystrophin gene therapy candidate for DMD that includes the CT domain, making it the closest to naturally occurring dystrophin. The inclusion of the CT domain is a key differentiator for RGX-202, potentially offering functional improvements in the DMD therapeutic landscape [2].

The company's Chief Scientific Officer, Olivier Danos, Ph.D., stated, "We specifically designed RGX-202 differently from other gene therapies with the goal of providing improved outcomes for patients, and this research further validates the potential therapeutic advantage of adding the CT domain and its importance in preventing the muscle breakdown associated with functional decline in Duchenne" [2].

The preclinical results are significant as they provide further evidence of the potential therapeutic benefits of RGX-202. The company's pipeline of one-time treatments for rare and retinal diseases includes RGX-202, which is designed to support the delivery and targeted expression of microdystrophin throughout skeletal and heart muscle using the NAV® AAV8 vector and a well-characterized muscle-specific promoter (Spc5-12) [2].

References:
[1] https://www.marketscreener.com/quote/stock/REGENXBIO-INC-23733717/news/Regenxbio-Inc-Announces-Publication-of-Preclinical-Results-Demonstrating-Functional-Benefits-of-Nov-50482789/
[2] https://www.prnewswire.com/news-releases/regenxbio-announces-publication-of-preclinical-results-demonstrating-functional-benefits-of-novel-microdystrophin-construct-in-rgx-202-investigational-gene-therapy-for-duchenne-muscular-dystrophy-302502606.html