- First patient received dose level 2 of RGX-202, a
potential one-time AAV Therapeutic for the treatment of Duchenne
that includes an optimized transgene for a novel
microdystrophin
- On track for pivotal dose determination and initiation of
pivotal program in 2024
ROCKVILLE, Md., Nov. 29,
2023 /PRNewswire/ -- REGENXBIO Inc. (Nasdaq: RGNX)
today announced that the first patient received RGX-202 at dose
level 2 in the Phase I/II AFFINITY DUCHENNE® trial.
RGX-202 is an investigational one-time AAV Therapeutic for
Duchenne muscular dystrophy (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.
"Progressing to dose level 2 is an important milestone in our
updated strategic plans and for accelerating the development of
RGX-202," said Kenneth T. Mills,
President and Chief Executive Officer of REGENXBIO. "There is a
large unmet need for new therapies for boys with Duchenne, and the
market is capable of supporting multiple gene therapies. We believe
RGX-202 has unique, differentiating features that support its
potential to be a best-in-class product."
Initial biomarker data in two patients who received RGX-202 at
dose level 1 who completed three-month assessment demonstrated
robust RGX-202 microdystrophin expression with localization to the
muscle cell membrane. In recently completed preclinical efficacy
studies, RGX-202 at dose level 2 showed improvement in functional
performance, compared to dose level 1, as determined by forelimb
muscle strength and treadmill exhaustion in mdx mice.
REGENXBIO expects to share initial strength and functional
assessment data for both dose levels and anticipates pivotal dose
determination and the initiation of a pivotal program in 2024. The
Company plans to use RGX-202 microdystrophin expression as a
surrogate endpoint to support a Biologics License Application (BLA)
filing using the accelerated approval pathway.
AFFINITY DUCHENNE Trial Design
The Phase I/II AFFINITY
DUCHENNE trial is a multicenter, open-label dose escalation and
dose expansion clinical study to evaluate the safety, tolerability
and clinical efficacy of a one-time intravenous (IV) dose of
RGX-202 in patients with Duchenne. In the dose evaluation phase of
the trial, four ambulatory, pediatric patients (ages 4 to 11 years
old) are expected to enroll in two cohorts with doses of
1x1014 (GC)/kg body weight (n=2) and
2x1014 GC/kg body weight (n=2). After an
independent safety data review for each cohort, a dose expansion
phase of the trial may allow for additional patients to be
enrolled.
The trial design was informed by the Duchenne community and
engagement with key opinion leaders, including a comprehensive,
short-term, prophylactic immunosuppression regimen to proactively
mitigate potential complement-mediated immunologic responses, and
inclusion criteria based on dystrophin gene mutation status,
including DMD gene mutations in exons 18 and above. Trial endpoints
include safety, immunogenicity assessments, pharmacodynamic and
pharmacokinetic measures of RGX-202, including microdystrophin
protein levels in muscle, and strength and functional assessments,
including the North Star Ambulatory Assessment (NSAA) and timed
function tests.
About RGX-202
RGX-202 is designed to deliver a
transgene for a novel microdystrophin that includes the functional
elements of the C-Terminal (CT) domain found in naturally occurring
dystrophin. 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, may potentially improve gene expression, increase
translational efficiency and reduce immunogenicity. RGX-202 is
designed to support the delivery and targeted expression of genes
throughout skeletal and heart 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 is a
severe, progressive, degenerative muscle disease, affecting 1 in
3,500 to 5,000 boys born each year worldwide. Duchenne is caused by
mutations in the Duchenne gene which encodes for dystrophin, a
protein involved in muscle cell structure and signaling pathways.
Without dystrophin, muscles throughout the body degenerate and
become weak, eventually leading to loss of movement and
independence, required support for breathing, cardiomyopathy and
premature death.
About REGENXBIO Inc.
REGENXBIO is a leading
clinical-stage biotechnology company seeking to improve lives
through the curative potential of gene therapy. REGENXBIO's NAV
Technology Platform, a proprietary adeno-associated virus (AAV)
gene delivery platform, consists of exclusive rights to more than
100 novel AAV vectors, including AAV7, AAV8 and AAV9. REGENXBIO and
its third-party NAV Technology Platform Licensees are applying the
NAV Technology Platform in the development of a broad pipeline of
candidates, including late-stage and commercial programs, in
multiple therapeutic areas. REGENXBIO is committed to a "5x'25"
strategy to progress five AAV Therapeutics from our internal
pipeline and licensed programs into pivotal-stage 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 a belief, expectation or intention and are generally
accompanied by words that convey projected future events or
outcomes such as "believe," "may," "will," "estimate," "continue,"
"anticipate," "assume," "design," "intend," "expect," "could,"
"plan," "potential," "predict," "seek," "should," "would" or by
variations of such words or by similar expressions. The
forward-looking statements include statements relating to, among
other things, REGENXBIO's future operations, clinical trials, costs
and cash flow. REGENXBIO has based these forward-looking statements
on its current expectations and assumptions and analyses made by
REGENXBIO in light of its experience and its perception of
historical trends, current conditions and expected future
developments, as well as other factors REGENXBIO believes are
appropriate under the circumstances. However, whether actual
results and developments will conform with REGENXBIO's expectations
and predictions is subject to a number of risks and uncertainties,
including the timing of enrollment, commencement and completion and
the success of clinical trials conducted by REGENXBIO, its
licensees and its partners, the timing of commencement and
completion 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 of product candidates, the ability to obtain
and maintain intellectual property protection for product
candidates and technology, trends and challenges in the 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, and other factors, many of which are beyond the control
of REGENXBIO. Refer to 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 ended December 31, 2022, and
comparable "risk factors" sections of REGENXBIO's Quarterly Reports
on Form 10-Q and other filings, which have been filed with the U.S.
Securities and Exchange Commission (SEC) and are available on the
SEC's website at WWW.SEC.GOV. All of the forward-looking statements
made in this press release are expressly qualified by the
cautionary statements contained or referred to herein. The actual
results or developments anticipated may not be realized or, even if
substantially realized, they may not have the expected consequences
to or effects on REGENXBIO or its businesses or operations. Such
statements are not guarantees of future performance and actual
results or developments may differ materially from those projected
in the forward-looking statements. Readers are cautioned not to
rely too heavily on the 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 does not undertake any obligation, and specifically
declines any obligation, to update or revise any forward-looking
statements, whether as a result of new information, future events
or otherwise.
Contacts:
Dana Cormack
Corporate Communications
dcormack@regenxbio.com
Investors:
Chris Brinzey
ICR Westwicke
339-970-2843
chris.brinzey@westwicke.com
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SOURCE REGENXBIO Inc.