Sarepta Therapeutics Announces Positive Functional Results from the SRP-9003 (MYO-101) Gene Therapy Trial to Treat Limb-Girdle Muscular Dystrophy Type 2E, or Beta-Sarcoglycanopathy
10/04/19 8:31 AM EDT
-- Improvements on functional measures seen in all three participants --
-- Significant reduction in creatine kinase maintained over nine months --
-- Results follow positive and robust expression and biomarker data presented earlier in 2019 --
In Cohort 1 of the SRP-9003 study, three participants ages 4-13 were treated with an infusion of SRP-9003 at a dose of 5x1013vg/kg. Improvements in functional outcomes were observed at day 270 (nine months) for all three participants.
“We have now observed consistent functional improvements, in addition to high levels of expression of the missing protein of interest and strong results in related biomarkers, in both of our first cohorts for Duchenne muscular dystrophy (SRP-9001) and LGMD2E (SRP-9003). We intend to test one higher dose of SRP-9003 in LGMD2E participants, select our clinical dose and then advance our SRP-9003 program, along with our other five LGMD programs, as rapidly as possible,” said
At Day 270, mean creatine kinase (CK) was significantly reduced compared to baseline. CK is an enzyme biomarker strongly associated with muscle damage.
At Day 270, all three participants showed improvements from baseline across all functional measures, including the North Star Assessment for Dysferlinopathy (NSAD), time to rise, four-stair climb, 100-m walk test and 10-meter walk test. These results are distinctly different from what an age-matched, natural history group would predict.
No new safety signals were observed and the safety profile seen to date supports the ability to dose escalate in the next cohort of the study. As previously disclosed, two participants in the study had elevated liver enzymes, one of which was designated a serious adverse event (SAE), as the participant had associated transient increase in bilirubin. Both events occurred when the participants were tapered off oral steroids and, in both instances, elevated liver enzymes returned to baseline and symptoms resolved following supplemental steroid treatment.
“LGMD2E is a devastating neuromuscular disease with no current treatment options so we are very pleased to observe a functional improvement in study participants who received SRP-9003,” said
Sarepta had previously shared expression results from the study, which found that in two-month post-treatment muscle biopsies, clinical trial participants showed a mean of 51% beta-sarcoglycan positive fibers, as measured by immunohistochemistry (IHC), substantially exceeding the pre-defined 20% measure for success. Mean fiber intensity, as measured by IHC, was 47% compared to normal control.
About SRP-9003 and the Phase I/IIa Gene Transfer Clinical Trial
SRP-9003 uses the AAVrh74 vector, which is designed to be systemically and robustly delivered to skeletal, diaphragm and cardiac muscle without promiscuously crossing the blood brain barrier, making it an ideal candidate to treat peripheral neuromuscular diseases. As a rhesus monkey-derived AAV vector, AAVrh74 has lower immunogenicity rates than reported with other common human AAV vectors. The MHCK7 promoter has been chosen for its ability to robustly express in the heart, which is critically important for patients with LGMD2E, many of whom die from pulmonary or cardiac complications.
This first-in-human study is evaluating a single intravenous infusion of SRP-9003 among children with LGMD2E between the ages of four and 15 years with significant symptoms of disease.
About Limb-Girdle Muscular Dystrophy
Limb girdle muscular dystrophies are genetic diseases that cause progressive, debilitating weakness and wasting that begin in muscles around the hips and shoulders before progressing to muscles in the arms and legs.
Patients with LGMD2E begin showing neuromuscular symptoms such as difficulty running, jumping and climbing stairs before age 10. The disease, which is an autosomal recessive subtype of LGMD, progresses to loss of ambulation in the teen years and often leads to death before age 30. There is currently no treatment or cure for LGMD2E.
Sarepta has five LGMD gene therapy programs in development, including subtypes for LGMD2E, LGMD2D, LGMD2C, LGMD2B and LGMD2L, and holds an option for a sixth program for LGMD2A.
Sarepta is at the forefront of precision genetic medicine, having built an impressive and competitive position in Duchenne muscular dystrophy (DMD) and more recently in gene therapies for Limb-girdle muscular dystrophy diseases (LGMD), MPS IIIA, Pompe and other CNS-related disorders, totaling over 20 therapies in various stages of development. The Company’s programs and research focus span several therapeutic modalities, including RNA, gene therapy and gene editing. Sarepta is fueled by an audacious but important mission: to profoundly improve and extend the lives of patients with rare genetic-based diseases. For more information, please visit www.sarepta.com.
This press release contains "forward-looking statements." Any statements contained in this press release that are not statements of historical fact may be deemed to be forward-looking statements. Words such as "believes," "anticipates," "plans," "expects," "will," "intends," "potential," "possible" and similar expressions are intended to identify forward-looking statements. These forward-looking statements include statements regarding our intention to test one higher dose of SRP-9003 in LGMD2E participants, select our clinical dose and then advance our SRP-9003 program, along with our other five LGMD programs, as rapidly as possible; Sarepta continuing to build an enduring gene therapy model created to design, develop and bring to the medical and patient community transformative therapies for those living with rare genetic disease; the safety profile of SRP-9003 seen to date supporting the ability to dose escalate in the next cohort of the study; SRP-9003 being an ideal candidate to treat peripheral neuromuscular diseases; the potential benefits of the AAVrh74 vector and the MHCK7 promoter; and our mission to profoundly improve and extend the lives of patients with rare genetic-based diseases.
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Source: Sarepta Therapeutics, Inc.
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