- Novel, one-time, direct-to-CNS treatment for MPS II focused toward potentially preventing the progression of cognitive
deficits
- Clinical trial expected to enroll children with MPS II
- Anticipate beginning trial enrollment during the first half of 2018
ROCKVILLE, Md., Dec. 19, 2017 (GLOBE NEWSWIRE) -- REGENXBIO Inc. (Nasdaq:RGNX), a leading clinical-stage biotechnology company
seeking to improve lives through the curative potential of gene therapy based on its proprietary NAV® Technology
Platform, today announced the Investigational New Drug application (IND) is active for the planned multi-center, open-label,
multiple-cohort, dose-escalation Phase I/II clinical trial of RGX-121 for the treatment of pediatric subjects with
Mucopolysaccharidosis Type II (MPS II).
“The goal of the RGX-121 program is to develop a single-dose treatment for MPS II that can prevent the progression of
neurocognitive decline experienced by children with the disease, which addresses one of the shortcomings of the current standard of
care, enzyme replacement therapy,” said Stephen Yoo, M.D., Chief Medical Officer of REGENXBIO. “We expect to commence trial
enrollment in the first half of 2018, and we look forward to working with leading gene therapy researchers and the broader MPS II
community on this novel clinical program.”
RGX-121 has received orphan drug designation as well as rare pediatric disease designation from the U.S. Food and Drug
Administration (FDA). Leading international gene therapy and lysosomal storage disease centers are expected to participate in the
Phase I/II trial of RGX-121.
About the Phase I/II Clinical Trial of RGX-121
RGX-121 will be evaluated in a Phase I/II, multi-center, open-label, multiple-cohort, dose-escalation study in pediatric
subjects with MPS II. Eligible patients must have documented evidence of early-stage neurocognitive deficit due to MPS.
Approximately six male subjects with MPS II greater than or equal to 4 months old and less than 5 years old will be treated in two
dose cohorts (1.3 × 1010 GC/g brain mass and 6.5 × 1010 GC/g brain mass), and will receive a single dose of
RGX-121 administered by an injection directly in the cerebrospinal fluid (CSF). Patients will receive immunosuppression for the
first year after RGX-121 is administered. The primary purpose of the clinical study is to assess the safety and tolerability of
RGX-121 at 24 weeks. Primary endpoints include adverse events, certain laboratory measures (including immunologic parameters) and
neurological examinations. The study will also assess biomarkers related to iduronate 2-sulfatase (I2S) protein activity within the
CSF, serum and urine. Following completion of the primary study period, subjects will continue to be assessed for a total of 104
weeks following treatment with RGX-121.
About Mucopolysaccharidosis Type II (MPS II)
MPS II is a rare x-linked recessive genetic disease caused by deficiency of I2S, an enzyme required for the breakdown of
polysaccharides in the lysosomes. These polysaccharides, called glycosaminoglycans (GAGs), accumulate in tissues of MPS II
patients, resulting in characteristic storage lesions and diverse clinical signs and symptoms including in the central nervous
system (CNS), which can include neural cell death, excessive accumulation of fluid in the brain, spinal cord compression and
cognitive impairment. MPS II is estimated to occur in 1 in 200,000 births. The current disease modifying therapy for MPS II is
enzyme replacement therapy with a recombinant form of human I2S administered intravenously. However, intravenous enzyme therapy
does not treat the CNS manifestations of MPS II.
About RGX-121
RGX-121 is being developed as a novel, one-time, direct-to-CNS treatment for MPS II that includes the NAV AAV9 vector encoding
for human I2S. Delivery of the enzyme that is deficient within cells in the CNS could provide a permanent source of secreted I2S
beyond the blood-brain barrier, allowing for long-term cross-correction of cells throughout the CNS. This strategy could also
provide rapid I2S delivery to the brain, potentially preventing the progression of cognitive deficits that otherwise occurs in MPS
II patients.
Treatment with RGX-121 has been shown to restore I2S expression in animal models of MPS II to levels equivalent to or greater
than those in non-affected animals. The extent of CNS correction in animal studies suggests that RGX-121 has the potential to be an
important and suitable therapeutic option for MPS II patients.
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, AAV9 and AAVrh10. REGENXBIO and its
third-party NAV Technology Platform Licensees are applying the NAV Technology Platform in the development of a broad pipeline of
candidates in multiple therapeutic areas.
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,” “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 research, development and regulatory plans in connection with its NAV Technology
Platform and gene therapy treatments. 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 of REGENXBIO’s clinical trials; the timing and
success of preclinical studies and clinical trials 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, 2016 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. 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.
CONTACT:
Investors
Natalie Wildenradt, 646-681-8192
natalie@argotpartners.com
Media
Adam Pawluk, 202-591-4063
apawluk@jpa.com
![Primary Logo](https://resource.globenewswire.com/Resource/Download/492da196-c4b9-4bd8-9a74-08fe2acb8114?size=1)
![](http://www.globenewswire.com/newsroom/ti?ndecode=NzA2MzkjNzA0OTY5Ng==)