Sarepta Therapeutics Announces Eteplirsen Demonstrates Sustained Benefit on Walking Test Through 74 Weeks in Phase IIb Study in

Sarepta Therapeutics Announces Eteplirsen Demonstrates Sustained Benefit on 
Walking Test Through 74 Weeks in Phase IIb Study in
Duchenne Muscular Dystrophy 
Data to Be Presented at the Muscular Dystrophy Association Scientific
CAMBRIDGE, MA -- (Marketwired) -- 04/05/13 --  Sarepta Therapeutics,
Inc. (NASDAQ: SRPT), a developer of innovative RNA-based
therapeutics, today announced updated data from Study 202, a Phase
IIb open-label extension study of eteplirsen in patients with
Duchenne muscular dystrophy (DMD). Results at 74 weeks showed a
continued stabilization of walking ability in eteplirsen-treated
patients evaluable on the 6-minute walk test (6MWT). As previously
reported, Study 202 met its primary endpoint of increased novel
dystrophin as assessed by muscle biopsy at week 48 and is now in the
long-term extension phase in which patients continue to be followed
for safety and clinical outcomes. Eteplirsen is Sarepta's lead
exon-skipping compound in development for the treatment of patients
with DMD who have a genotype amenable to skipping of exon 51. 
After 74 weeks, patients in the 30 mg/kg and 50 mg/kg dose cohorts
who were able to perform the 6MWT (modified Intent-to-Treat or mITT
population; n=6) showed a statistically significant treatment benefit
of 65.2 meters (p ≤ 0.004) when compared to the
placebo/delayed-treatment cohort (n=4). The eteplirsen-treated
patients in the mITT population demonstrated less than a 5 percent
decline (13.4 meters) from baseline in walking ability. After
experiencing a substantial decline earlier in the study, the
placebo/delayed-treatment cohort also demonstrated stabilization in
walking ability from week 36 through 74, the period in which
meaningful levels of dystrophin were likely produced, with a less
than 10 meter decline over this timeframe. 
"We are encouraged to see a continued stabilization of walking
ability in patients treated with eteplirsen for nearly one and a half
years," said Chris Garabedian, president and chief executive officer
of Sarepta Therapeutics. "These data are particularly compelling when
viewed in the context of published natural history studies, which
showed substantial declines on the 6-minute walk test over this
timeframe in a similar ambulatory DMD population. These results
tinue to support the potential of eteplirsen to be a major advance
in the treatment of DMD in altering the course of this progressive
and irreversible disease."  
Through 74 weeks, eteplirsen was well tolerated and there were no
clinically significant treatment-related adverse events, serious
adverse events, hospitalizations or discontinuations. As previously
reported at 62 weeks, one patient had a transient elevation of urine
protein on a laboratory urine dipstick test, which resolved and
resulted in no clinical symptoms. The patient continued treatment
without interruption and remained free of proteinuria through week
Across both the eteplirsen (mITT) and placebo/delayed-treatment
cohorts, there is evidence of continued stabilization on clinical
laboratory tests, echocardiogram, pulmonary function tests and muscle
Summary of Additional 6MWT Analyses 
Patients performed two 6MWT evaluations on consecutive days at time
points coinciding with a muscle biopsy procedure at baseline and
weeks 12, 24 and 48. All other evaluations were a single 6MWT. The
pre-specified primary analysis included the maximum distance walked
at those clinic visits where repeated tests were taken. Other
analyses of the repeated 6MWT results assessed mean, minimum, and day
1 (first measure) scores. Results from these additional 6MWT analyses
confirm the robust treatment effect observed in the primary analysis. 
Summary of 6MWT: Eteplirsen (mITT) versus Placebo/Delayed-Treatment
to Week 74* 

                                    Mean 6MWT  Estimated                    
Analysis of Repeated     Baseline   Change     Treatment Benefit            
6MWT Values              6MWT       from       (Eteplirsen Minus  P-Value   
                         (meters)   Baseline   Placebo/delayed-             
                                    (meters)   Tx)                          
Maximum Score                                                     ≤   
Eteplirsen (n=6)         399.7      -13.4      65.2 m             0.004     
Maximum Score                                                               
Placebo/delayed-Tx (n=4) 394.5      -78.6                                   
Mean Score                                                        ≤   
Eteplirsen (n=6)         388.6      -2.2       62.4 m             0.007     
Mean Score                                                                  
Placebo/delayed-Tx (n=4) 380.3      -64.6                                   
Minimum Score                                                     ≤   
Eteplirsen (n=6)         377.5      +9.0       59.6 m             0.015     
Minimum Score                                                               
Placebo/delayed-Tx (n=4) 366.0      -50.6                                   
Day 1 Score                                                       ≤   
Eteplirsen (n=6)         379.7      +6.6       62.2 m             0.013     
Day 1 Score                                                                 
Placebo/delayed-Tx (n=4) 371.5      -55.6                                   

*All analyses are based on a Mixed Model Repeated Measures test. 
Jerry R. Mendell, M.D., Director of the Centers for Gene Therapy and
Muscular Dystrophy at Nationwide Children's Hospital and principal
investigator of the Phase IIb study, will present these data in an
oral presentation at the Muscular Dystrophy Association Scientific
Conference on Tuesday, April 23 at 4:05 p.m. EDT in Washington, D.C.
Dr. Mendell's presentation will be posted on the Sarepta website in
the "Events & Presentations" section after the session is completed.  
About the Phase IIb Eteplirsen Program (Studies 201 and 202) 
Study 201 was a randomized, double-blind, placebo-controlled clinical
study conducted at Nationwide Children's Hospital in Columbus, Ohio.
Twelve boys aged 7-13 years with a confirmed genotype amenable to
treatment with an exon-51 skipping drug were randomized to one of
three cohorts: 30 mg/kg (n=4), 50 mg/kg (n=4), and placebo/delayed
treatment (n=4). Eteplirsen and placebo were administered weekly by
intravenous infusion.  
At Week 25, all patients rolled over to Study 202, a long-term
open-label extension study, and placebo-treated
 patients initiated
eteplirsen treatment at 30 mg/kg (n=2) or 50 mg/kg (n=2). 
The primary efficacy endpoint in Study 201 and Study 202 was the
increase in novel dystrophin as assessed by muscle biopsy at weeks 12
and 24 and at week 48, respectively. The primary clinical endpoint
was the 6MWT, a well-accepted measure of ambulation and clinical
function in DMD. Long-term follow up in Study 202 continues to
evaluate safety and clinical outcomes including the 6MWT every 12
About the 6-Minute Walk Test (6MWT) 
The 6-minute walk test (6MWT) was developed as an integrated
assessment of cardiac, respiratory, circulatory, and muscular
capacity (American Thoracic Society 2002) for use in clinical trials
of various cardiac and pulmonary conditions. In recent years the 6MWT
has been adapted to evaluate functional capacity in neuromuscular
diseases and has served as the basis for regulatory approval of a
number of drugs for rare diseases, with mean changes in the 6MWT
ranging from 28 to 44 meters (Rubin 2002, Wraith 2004, Muenzer 2006).
Additionally, published data from longitudinal natural history
studies assessing dystrophinopathy, a disease continuum comprised of
DMD and Becker muscular dystrophy, support the utility of the 6MWT as
a clinically meaningful endpoint (McDonald 2010) in DMD. These data
show that boys with DMD experience a significant decline in walking
ability compared to healthy boys over one year, suggesting that
slowing the loss of walking ability is a major treatment goal. 
About the Statistical Methodology and the Modified Intent-to-Treat
(mITT) Population  
The Mixed Model Repeated Measures (MMRM) test was used for all
statistical analyses of the 6MWT results, including for all
subgroups. Analysis of Covariance (ANCOVA) for ranked data was used
when the assumptions of normality of the dependent variable (the
change in 6MWT distance from baseline) were violated. Baseline 6MWT
scores and duration since DMD diagnosis were included as covariates. 
The mITT population used in the 6MWT analyses consisted of 10 of the
12 enrolled patients, including 4 patients in the 50 mg/kg cohort, 2
patients in the 30 mg/kg cohort and 4 patients in the
placebo/delayed-treatment cohort. Two patients in the 30 mg/kg cohort
showed rapid disease progression upon enrollment and lost ambulation
by week 24, and thus were excluded. 
About Duchenne Muscular Dystrophy 
DMD is an X-linked rare, degenerative neuromuscular disorder causing
severe progressive muscle loss and premature death. One of the most
common fatal genetic disorders, DMD affects approximately one in
every 3,500 boys worldwide. A devastating and incurable
muscle-wasting disease, DMD is associated with specific errors in the
gene that codes for dystrophin, a protein that plays a key structural
role in muscle fiber function. Progressive muscle weakness eventually
spreads to the arms, neck and other areas. Eventually, this
progresses to complete paralysis and increasing difficulty in
breathing due to respiratory muscle dysfunction requiring ventilation
support, as well as cardiac dysfunction leading to heart failure. The
condition is terminal, and death usually occurs before the age of 30. 
About Sarepta's Proprietary Exon-Skipping Platform Technology 
Eteplirsen is Sarepta's lead drug candidate that is designed to
address the underlying cause of DMD by enabling the production of a
functional dystrophin protein. Data from clinical studies of
eteplirsen in DMD patients have demonstrated a broadly favorable
safety and tolerability profile and restoration of dystrophin protein
Eteplirsen uses Sarepta's novel phosphorodiamidate morpholino
oligomer (PMO)-based chemistry and proprietary exon-skipping
technology to skip exon 51 of the dystrophin gene enabling the repair
of specific genetic mutations that affect approximately 13 percent of
the total DMD population. By skipping exon 51, eteplirsen may restore
the gene's ability to make a shorter, but still functional, form of
dystrophin from messenger RNA, or mRNA. Promoting the synthesis of a
truncated dystrophin protein is intended to improve, stabilize or
significantly slow the disease process and prolong and improve the
quality of life for patients with DMD. 
Sarepta is also developing other PMO-based exon-skipping drug
candidates intended to treat additional patients with DMD. 
About Sarepta Therapeutics 
Sarepta Therapeutics is focused on developing first-in-class
RNA-based therapeutics to improve and save the lives of people
affected by serious and life-threatening rare and infectious
diseases. The Company's diverse pipeline includes its lead program
eteplirsen, for Duchenne muscular dystrophy, as well as potential
treatments for some of the world's most lethal infectious diseases.
Sarepta aims to build a leading, independent biotech company
dedicated to translating its RNA-based science into transformational
therapeutics for patients who face significant unmet medical needs.
For more information, please visit us at 
Forward-Looking Statements and Information  
This press release contains forward-looking statements. These
forward-looking statements generally can be identified by use of
words such as "believes or belief," "anticipates," "plans,"
"expects," "will," "intends," "potential," "possible," "advance" and
similar express
ions. These forward-looking statements include
statements about the development of eteplirsen and its efficacy,
potency and utility in the treatment of DMD and the potential for the
creation of novel dystrophin to lead to significant clinical benefit
over a longer course of treatment.  
Each forward-looking statement contained in this press release is
subject to risks and uncertainties that could cause actual results to
differ materially from those expressed or implied by such statement.
Applicable risks and uncertainties include, among others: subsequent
clinical trials may fail to demonstrate the safety and efficacy of
eteplirsen or replicate results; treatment of patients with DMD using
eteplirsen over a longer duration may not lead to significant
clinical benefit; any of Sarepta's drug candidates, including
eteplirsen, may fail in development, may not receive required
regulatory approvals, or may not become commercially viable due to
delays or other reasons; and those identified under the heading "Risk
Factors" in Sarepta's Annual Report on Form 10-K for the full year
ended December 31, 2012, and filed with the Securities and Exchange
Any of the foregoing risks could materially and adversely affect
Sarepta's business, results of operations and the trading price of
Sarepta's common stock. For a detailed description of risks and
uncertainties Sarepta faces, you are encouraged to review
Company's filings with the Securities and Exchange Commission. We
caution investors not to place considerable reliance on the
forward-looking statements contained in this press release. Sarepta
does not undertake any obligation to publicly update its
forward-looking statements based on events or circumstances after the
date hereof. 
"Safe Harbor" Statement under the Private Securities Litigation
Reform Act of 1995: The statements that are not historical facts
contained in this release are forward-looking statements that involve
risks and uncertainties, including, but not limited to, the results
of research and development efforts, the results of preclinical and
clinical testing, the effect of regulation by the FDA and other
agencies, the impact of competitive products, product development,
commercialization and technological difficulties, and other risks
detailed in the company's Securities and Exchange Commission filings. 
Sarepta Investor Contact: 
Erin Cox 
Sarepta Media Contact:
Jim Baker
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