RGX-202, an investigational gene therapy for the treatment of Duchenne muscular dystrophy: Interim clinical data

Topic:

Clinical Trials

Poster Number: M150

Author(s):

Aravindhan Veerapandiyan, MD, Arkansas Children's Hospital, UAMS Health, Vamshi K. Rao, MD, Division of Neurology, Ann and Robert H. Lurie Children’s Hospital of Chicago, Chicago, IL, USA, Jahannaz Dastgir, DO, REGENXBIO, Inc., Paulo Falabella, MD PhD, REGENXBIO, Inc., Stephen Pakola, MD, REGENXBIO, Inc., Sarang Rastogi, PharmD, REGENXBIO, Inc., Dawn Phillips, REGENXBIO, Inc., Catherine Wilson, REGENXBIO, Inc., Nidal Boulos, REGENXBIO, Inc., Michelle Gilmor, PhD, REGENXBIO Inc. - Rockville, MD, Lin Yang, PhD, REGENXBIO, Inc., Hiren Patel, PhD, REGENXBIO, Inc., Michele Fiscella, PhD, REGENXBIO, Inc., Olivier Danos, PhD, Regenxbio, Inc.

OBJECTIVE: _x000D_
To evaluate safety and efficacy of RGX-202 in patients with Duchenne muscular dystrophy (DMD) aged 4 to 11 years._x000D_
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BACKGROUND: _x000D_
Duchenne Muscular Dystrophy (Duchenne) is a rare, X-linked, progressive muscle disease due to pathogenic variants in the DMD gene which encodes for the sarcolemmal protein, dystrophin. The absence of functional dystrophin results in muscle cell damage, eventual loss of ambulation, and weakness of cardiac muscle and the diaphragm, presenting as cardiomyopathy and respiratory failure._x000D_
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DESIGN/METHODS:_x000D_
RGX-202 is an investigational one-time AAV therapeutic for Duchenne, using the NAV® AAV8 vector to deliver a transgene for a novel microdystrophin that includes the functional elements of the C-Terminal (CT) domain as well as a muscle-specific promoter to support a targeted therapy for improved resistance to muscle damage associated with Duchenne._x000D_
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RESULTS: _x000D_
As of September 28, 2023, after 3 weeks to over 5 months of follow-up, a single dose of RGX-202 was reported to be well tolerated with no drug-related serious adverse events (SAEs) in three patients receiving dose level 1, 1×1014 genome copies (GC)/kg. The prophylactic immune suppression for RGX-202 gene therapy has also been well tolerated. Initial biomarker data from two patients indicated increased expression of RGX-202 microdystrophin from muscle biopsies taken at three months. RGX-202 microdystrophin expression measured via western blot (Jess) was 38.8% compared to control in the 4.4 year old and 11.1% compared to control in the 10.6 year old. Serum creatine kinase levels decreased between baseline to 10 weeks by 43% in the 4.4 year old and by 44% in the 10.6 year old. In addition, RGX-202 microdystrophin was detectable by immunofluorescence and localized to the sarcolemma throughout the muscle tissue at three months._x000D_
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CONCLUSIONS: _x000D_
RGX-202 has been well tolerated in 3 participants up to 25 weeks post-administration of RGX-202 with no drug-related SAEs.