REGENXBIO Announces Phase I/II Trial of RGX-202, Novel Gene Therapy Candidate for Duchenne Muscular Dystrophy, Is Active and Recruiting Patients

The company launched Phase I/II AFFINITY DUCHENNE testing RGX-202
The company is also including a new active observational screening study, AFFINITY BEYOND, evaluating the prevalence of AAV8 antibodies in boys with Duchenne
Commercial cGMP material from REGENXBIO Manufacturing Innovation Center to be used in clinical trial
RGX-202 is a potential single-agent AAV therapeutic for the treatment of Duchenne disease and includes an optimized transgene for a novel microdystrophin and REGENXBIO’s proprietary NAV® AAV8 vector

ROCKVILLE, Md., January 23, 2023 /PRNewswire/ — REGENXBIO Inc. (Nasdaq: RGNX) today announced that Phase I/II AFFINITY DUCHENNE the RGX-202 trial for the treatment of Duchenne muscular dystrophy (Duchenne) is now active and recruiting patients. RGX-202 is designed to deliver a transgene for a novel microdystrophin protein that includes functional elements of the C-Terminal (CT) domain found in native dystrophin. RGX-202 uses REGENXBIO proprietary NAV® AAV8 vector.

AFFINITY DUCHENNE is a multicenter, open-label dose evaluation and dose-escalation clinical trial to evaluate the safety, tolerability, and clinical efficacy of a single intravenous (IV) dose of RGX-202 in patients with Duchenne disease.

In addition, REGENXBIO is recruiting patients to AFFINITY BEYOND trial, observational screening study. The primary objective is to assess the prevalence of AAV8 antibodies in Duchenne patients up to 12 years of age. The information collected in this study may be used to identify potential participants for the AFFINITY DUCHENNE trial and potential future trials of RGX-202.

“I am pleased that we can now initiate the RGX-202 trial and begin enrollment activities in our AAV8 antibody screening study,” he said. Kenneth T. Mills, President and CEO of REGENXBIO. “The RGX-202 program is a key part of our ‘5x’25’ strategy to have five AAV therapeutics on the market or in late-stage development by 2025. We look forward to continuing to work closely with the Duchenne community while advancing a highly differentiated product candidate developed with the potential to improve muscle strength and motor function in boys with Duchenne.”

“Duchenne muscular dystrophy is a devastating disease and there are still unmet therapeutic needs,” said Aravindhan Veerapandiyan, MD, principal investigator on the study and director of the Comprehensive Neuromuscular Program, a PPMD ​​certified Duchenne care center and co-director of the Muscular Center. for the care of the Dystrophy Association at Arkansas Children’s Hospital. “Gene therapies, like RGX-202, have the potential to affect the progressive nature of Duchenne.”

REGENXBIO produced additional clinical stock of RGX-202 in its own Manufacturing Innovation Center using NAVXpress process platform. Located at REGENXBIO’s 132,000 square foot headquarters in Rockville, MD, the Manufacturing Innovation Center is designed to meet global clinical and commercial regulatory standards and includes two independent drug substance mass production suites, a final drug kit and integrated laboratories for quality control. REGENXBIO is one of only a few gene therapy companies in the world with a cGMP facility capable of producing up to 2000 liters.

Additional information can be found at for AFFINITY DUCHENNE and AFFINITY BEYOND.

To shape

In the dose study phase, six outpatient pediatric patients (aged 4 to 11 years) with Duchenne are expected to be enrolled in two dose groups of 1×1014 genome copy (GC)/kg body weight (n=3) and 2×1014 GC/kg body weight (n=3). After independent review of safety data for each cohort, the dose-escalation phase of the trial may allow enrollment of up to six additional patients at each dose level (for a total of up to nine patients in each dose group).

The trial design also consists of thorough safety measures informed by the Duchenne community and engagement with key opinion makers, including a comprehensive, short-term, prophylactic immunosuppression regimen to proactively mitigate potential complement-mediated immune responses, and inclusion criteria based on dystrophin gene mutation status, including DMD gene mutations in exons 18 and above. Trial endpoints include assessment of safety, immunogenicity, pharmacodynamic and pharmacokinetic measures of RGX-202, including muscle microdystrophin protein levels, and assessment of strength and function, including the North Star Ambulatory Assessment (NSAA) and timed function tests. The initial trial sites are located in the US, with additional sites in the Canada and Europe expected to follow.

AFFINITY BEYOND Observational study

AFFINITY BEYOND is an observational screening study. The primary objective is to assess the prevalence of anti-adeno-associated antibodies to serotype 8 (AAV8) in participants with Duchenne muscular dystrophy. AAV gene therapies are delivered via viral vectors that are not known to cause disease in humans. For AAV gene therapies delivered systemically, it is important to test patients for antibodies to the vector. This observational study aims to aid future clinical research in Duchenne.

About the RGX-202

RGX-202 is designed to deliver a transgene for a novel microdystrophin that includes functional elements of the C-Terminal (CT) domain found in natural dystrophin. The presence of the CT domain has been shown in preclinical studies to recruit several key proteins to the muscle cell membrane, leading to improved muscle resistance to contraction-induced muscle damage in dystrophic mice. Additional design features, including codon optimization and reduction of CpG content, can potentially improve gene expression, increase translational efficiency, and reduce immunogenicity. RGX-202 is designed to support delivery and targeted gene expression across skeletal and cardiac muscle using the NAV AAV8 vector, a vector used in numerous clinical trials, and a well-characterized muscle-specific promoter (Spc5-12).

About Duchenne muscular dystrophy

Duchenne muscular dystrophy (Duchenne) is a rare genetic disorder caused by mutations in the gene responsible for the production of dystrophin, a protein of central importance for the structure and function of muscle cells. Duchenne primarily affects men with approximately 1 in 3,500 to 1 in 5,000 men worldwide. The lack of functional dystrophin protein in people with Duchenne results in cell damage during muscle contraction, leading to cell death, inflammation and fibrosis in muscle tissue. Initial symptoms of Duchenne disease include muscle weakness that is often apparent at an early age, with diagnosis usually occurring by age 5. Over time, people with Duchenne experience progressive muscle weakness and eventually lose the ability to walk. The respiratory and heart muscles are also affected, which leads to difficulty breathing and the need for a ventilator, along with the development of cardiomyopathy. There is currently no cure for Duchenne.


REGENXBIO is a leading clinical biotechnology company that strives to improve lives through the healing potential of gene therapy. The REGENXBIO NAV technology platform, a proprietary adenovirus-associated virus (AAV) gene delivery platform, consists of exclusive rights to more than 100 novel AAV vectors, including AAV7, AAV8, AAV9 and AAVrh10. REGENXBIO and third-party licensees of the NAV technology platform are applying the NAV technology platform in the development of a wide variety of candidates, including late-stage and commercial programs, in multiple therapeutic areas. REGENXBIO is committed to a “5x’25” strategy to advance five AAV therapeutics from our internal pipeline and licensed programs into pivotal or commercial products by 2025.

Forward-looking statements

This press release includes “forward-looking statements” within the meaning of Section 27A of the Securities Act of 1933, as amended, and Section 21E of the Securities Exchange Act of 1934, as amended. These statements express belief, expectation or intent and are generally accompanied by words conveying anticipated future events or outcomes such as “believe,” “may,” “will,” “estimate,” “continue,” “anticipate,” “assume , ” “design”, “intend”, “expect”, “could”, “plan”, “potential”, “anticipate”, “seek”, “should”, “would” or variations of such words or similar expressions. Forward-looking statements include statements regarding, among other things, REGENXBIO’s future operations and clinical trials. REGENXBIO has based these forward-looking statements on its current expectations and assumptions and analyzes made by REGENXBIO in light of its experience and perception of historical trends, current conditions and expected future developments, as well as other factors that REGENXBIO believes are appropriate under the circumstances. However, whether actual results and developments will be consistent with REGENXBIO’s expectations and projections is subject to a number of risks and uncertainties, including the timing of enrollment, initiation and completion, and the success, initiation and completion of clinical trials conducted by REGENXBIO, its licensees and its partners and the success of preclinical studies conducted by REGENXBIO and its development partners, the timely development and launch of new products, the ability to obtain and maintain regulatory approval for product candidates, the ability to obtain and maintain intellectual property protection for product candidates and technology, trends and challenges in business and markets in which REGENXBIO operates, the size and growth of potential markets for product candidates and the ability to serve those markets, the rate and degree of acceptance of product candidates, the impact of the COVID-19 Pandemic or similar public health crisis on REGEN XBIO’s business and other factors, from many of whom are execs an control of REGENXBIO. See the “Risk Factors” and “Management’s Discussion and Analysis of Financial Condition and Results of Operations” sections of REGENXBIO’s Annual Report on Form 10-K for the year then ended December 31, 2021, and the comparable “risk factors” sections of REGENXBIO’s quarterly reports on Form 10-Q and other filings, which are filed with the U.S. Securities and Exchange Commission (SEC) and are available on the SEC’s website at www.sec. Gov. All forward-looking statements made in this press release are expressly qualified by the cautionary statements contained or referred to herein. Anticipated actual results or developments may not be realized or, even if they are substantially realized, may not have the expected consequences or effects on REGENXBIO or its business or operations. Such statements are not guarantees of future performance and actual results or developments may differ materially from those anticipated in the forward-looking statements. Readers are cautioned not to place undue reliance on forward-looking statements contained in this press release. These forward-looking statements speak only as of the date of this press release. Except as required by law, REGENXBIO undertakes no obligation, and specifically disclaims any obligation, to update or revise any forward-looking statements, whether as a result of new information, future events or otherwise.

Dana Cormack
corporate communications
[email protected]

Chris BrinzeyICR Westwicke
[email protected]


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