REGENXBIO Advances in Duchenne Gene Therapy With Enrollment Completion and Production Initiation

REGENXBIO's Commitment to Duchenne Muscular Dystrophy

In an exciting development for the Duchenne muscular dystrophy (DMD) community, REGENXBIO Inc., a pioneering biotechnology company, has successfully completed the enrollment in the pivotal AFFINITY DUCHENNE® trial for RGX-202. This investigational gene therapy aims to revolutionize treatment options for individuals suffering from this degenerative condition, with a strong focus on providing consistent microdystrophin expression and measurable functional improvements.

A Landmark in Clinical Trials

The AFFINITY DUCHENNE trial has reached a critical milestone, completing the enrollment of 30 participants as of October 2025. The Phase I/II portion of this trial has showcased promising results, demonstrating microdystrophin levels ranging from 20% to an impressive 122%. These figures highlight the potential of RGX-202 to not only enhance clinical outcomes but also to be a viable treatment option as the data suggests a positive safety and efficacy profile with no serious adverse events reported thus far.

Curran Simpson, President and CEO of REGENXBIO, emphasized the company's commitment to addressing the urgent needs of the Duchenne community, stating, "The Duchenne community urgently needs new treatment options that provide durable, safe outcomes and can meaningfully change the course of this degenerative disease. Completing this pivotal trial milestone and manufacturing in-house our first doses intended for commercial use bring us even closer to delivering RGX-202 as a potential best-in-class gene therapy for Duchenne patients with limited options."

Commercial Production Kicks Off

In tandem with its clinical advancements, REGENXBIO has also initiated the commercial production of RGX-202 at its Manufacturing Innovation Center, located in Rockville, Maryland. With a capacity to produce up to 2,500 doses of RGX-202 annually, the company aims to meet the anticipated demand once regulatory approval is obtained. The production process is based on the proprietary NAVXpress® suspension technology, which promises industry-leading product purity levels exceeding 80% full capsids.

Looking Ahead

The topline data from the pivotal trial is expected to be announced in early Q2 2026, with a Biologics License Application (BLA) submission anticipated in mid-2026. These forthcoming steps are crucial as they could pave the way for RGX-202 to enter a rapidly growing market, where the demand for effective DMD treatments is highly pronounced. REGENXBIO is actively enrolling additional participants aged one year and above in confirmatory trials, underscoring its commitment to further validate the therapy's efficacy.

The company’s innovative use of the NAV® AAV8 vector, combined with a muscle-specific promoter, ensures targeted expression of microdystrophin throughout both skeletal and cardiac muscles, addressing one of the key challenges in DMD therapies. This meticulous design, incorporating features such as codon optimization, aims to enhance gene expression while minimizing immunogenicity—an essential consideration in the development of sustainable gene therapies.

Conclusion

REGENXBIO's recent advancements in the development of RGX-202 hold significant promise for individuals living with Duchenne muscular dystrophy. By achieving key enrollment milestones and kickstarting production, the company is on the cusp of potentially transforming the therapeutic landscape for this condition. The medical community, patients, and their families will be keenly watching the upcoming data and developments from REGENXBIO as they work towards bringing this innovative therapy to market.