Treatment With VP20621 (Non-Toxigenic Clostridium difficile; NTCD) In A Phase 2 Study Resulted In High Rates Of Colonization And

Treatment With VP20621 (Non-Toxigenic Clostridium difficile; NTCD) In A Phase
 2 Study Resulted In High Rates Of Colonization And Statistically Significant
              Reductions In Recurrence Of C. difficile Infection

PR Newswire

EXTON, Pa., April 22, 2013

EXTON, Pa., April 22, 2013 /PRNewswire/ -- ViroPharma Incorporated (Nasdaq:
VPHM), an international biopharmaceutical company committed to developing and
commercializing innovative products that address unmet medical needs and rare
diseases, today announced the results of a Phase 2 study of VP20621
(non-toxigenic Clostridium difficile; NTCD) a novel treatment approach for
preventing recurrent C. difficile infections (CDI). CDI is a common and
dangerous gastrointestinal infection typically occurring in older adults after
use of antibiotic medications. VP20621 contains the spores of a naturally
occurring non-toxin producing strain of C. difficile.

In this study of 168 patients who were randomized and dosed following
antibiotic treatment for CDI, VP20621 was well tolerated, with mild-moderate
headache the only notable associated adverse event reported by 10 percent of
subjects compared to 2 percent on placebo. Viable non-toxigenic C. difficile
was detected in stool culture (the primary endpoint of the study) in 54
percent of subjects treated with the low dose of VP20621 and up to 79 percent
of those receiving the high dose. In addition, across all dose groups, VP20621
reduced the incidence of CDI recurrence (a secondary endpoint of the study) by
greater than or equal to 50 percent vs. placebo, with a similar reduction in
antibacterial treatment for CDI vs. placebo in this study. The CDI recurrence
rate was two percent (2/86) in the subgroup of patients successfully colonized
with VP20621.

"These data demonstrate that colonization with VP20621 was achieved in the
majority of patients, and that in these patients, 98 percent had no recurrence
of C. difficile infection," commented Dr. Colin Broom, ViroPharma's chief
scientific officer. "We have long known that colonization of susceptible
individuals with a non-toxin-producing strain of C. difficile appears to
prevent infection by a toxic, virulent strain and these data support that
observation. The results of the study provide insight into how colonization
rates may be increased further, for example, by starting VP20621 dosing
earlier and using the optimum dosing regimen in confirmatory studies powered
to show a difference in recurrence rates. These are very exciting data, and
offer clinicians and patients hope that a preventive therapy for recurrent CDI
may one day be available to them."

About the Phase 2 study
The Phase 2 randomized, double-blind study was designed to determine the
tolerability of VP20621 dosed orally for up to 14 days in adults previously
treated for CDI with oral vancomycin or metronidazole. After completing the
antibiotic treatment, subjects were given either placebo (n=43), or VP20621
doses of 10^4 spores QD (once per day) for 7 days (n=41), 10^7 spores QD for 7
days (n=43), or 10^7 spores QD for 14 days (n=41). The overall median age of
study subjects was 59 years; 39 percent were >/= 65 years old; 62 percent were
female. Data from the study are shown below:

Microbiology and Clinical endpoints:
Study drug was to be administered to all subjects for 14 days to maintain the
blind. Data below pertain to the 6 weeks following the first dose of study
drug, which defined the period for evaluation of CDI recurrence. Colonization
was determined by microbiological culture of stool and CDI recurrence was
defined as >/= 3 unformed stools within 24 hours, positive C. difficile stool
assay and no other likely cause of diarrhea occurring after day one through
week 6.

Detection of NTCD in stool and rates of CDI recurrence, Antibacterial Use for
CDI Treatment and Clinical Diarrhea Events; Placebo vs. VP20621

                            Placebo 10^4x 7d 10^7x 7d 10^7x 14d All VP20621
n                           43      41        43        41         125
NTCD detected in stool
                            0%      54%       79%       73%        69%
14 day administration
p value vs. placebo                 <0.0001   <0.0001   <0.0001    <0.0001
CDI Recurrence              30%     15%       5%        15%        11%
p value vs. placebo                 0.11      <0.01     0.10       <0.01
Antibacterial Use for CDI
                            33%     15%       9%        17%        14%
p value vs. placebo                 0.06      0.02      0.14       <0.01
Event of diarrhea or loose
stool                       77%     56%       58%       56%        57%

of any severity or duration
p value vs. placebo                 0.05      0.09      0.02       0.02


VP20621 exhibited a favorable tolerability profile:

  oThere were no notable differences in adverse events between the different
    VP20621 dose groups;
  oOverall, treatment-emergent adverse events were reported in 86 percent of
    placebo subjects and 78 percent of all VP20621 subjects;
  oTreatment-emergent serious adverse events were reported in 7 percent and 3
    percent of placebo and VP20621 subjects, respectively, though none were
    considered related to study drug;
  oDiarrhea events are shown in the table above. Abdominal pain was reported
    in 33 percent of placebo subjects and 17 percent of all VP20621 subjects;
  oThe only adverse event with apparent association with VP20621 was
    headache: Two percent for placebo subjects vs. 10 percent for all VP20621
  oThere were 2 deaths:

       oOne subject in the placebo group had severe recurrent CDI that did
         not respond to attempted fecal transplant; death was attributed to
         the CDI and subsequent respiratory failure;
       oOne subject in the VP20621 high-dose (14 day) group was diagnosed
         with recurrent CDI and fell and fractured a hip; death was attributed
         to renal failure and pulmonary sepsis.

"I am thrilled by the data from this Phase 2 study of VP20621, which confirm
the therapeutic potential of non-toxigenic C. difficile," commented Dale
Gerding, MD, Professor of Medicine at Loyola University Chicago Stritch School
of Medicine and research physician at the Hines VA Hospital. "For the first
time, we have been able to mimic the protective effect we have inferred from
observing natural colonization of patients with non-toxigenic strains of C.
difficile. As a clinician on the front lines of CDI research, I find these
data to be extremely promising and suggestive of a novel approach to
prevention of not only disease recurrence, but primary CDI as well."

Next steps
ViroPharma will complete the evaluation of these Phase 2 data which will help
determine a future development pathway. The company reminds its investors that
VP20621 was flagged as a non core asset at its September investor event. With
these compelling Phase 2 clinical results, we will seek a partner to complete
the development and commercialization of the asset.

About VP20621
Antibiotics including those used to treat acute C. difficile infection (CDI)
disrupt the normal gastrointestinal flora which renders individuals
susceptible to C. difficile colonization. Orally-dosed liquid VP20621 utilizes
non-toxigenic spore-based technology as a potential means of recolonization
and protection. The goal of VP20621 dosing following antibiotic exposure is to
colonize with this non-toxigenic strain of C. difficile and to prevent
colonization by toxigenic strains, thereby preventing disease. VP20621 may
have therapeutic utility in the prevention of recurrence following treatment
of acute CDI and in the primary prevention of CDI. ViroPharma acquired VP20621
in 2006, through a licensing agreement with Dr. Dale N. Gerding, Professor of
Medicine at Loyola University Chicago.

About Clostridium difficile
One of the most serious problems facing the U.S. healthcare system today is
hospital-acquired infections (HAIs) and Clostridium difficile infection is one
of the most common and devastating HAIs. The incidence of C. difficile
observed in U.S. healthcare facilities more than doubled approximately every
five years since 1999 and the reported mortality rates from C. difficile in
the U.S. have more than quadrupled in the last decade to 14,000 per year.
Elderly patients exposed to antibiotics, long-term care patients, or those who
have a serious underlying illness are at greatest risk to contract the
disease. Typical symptoms include diarrhea (which can be severe), fever,
nausea, abdominal pain, and dehydration that can lead to life-threatening
complications such as shock, megacolon, peritonitis and perforation of the

About ViroPharma Incorporated
ViroPharma Incorporated is an international biopharmaceutical company
committed to developing and commercializing novel solutions for physician
specialists to address unmet medical needs of patients living with diseases
that have few if any clinical therapeutic options.ViroPharma is developing a
portfolio of therapeutics for rare and Orphan diseases including C1 esterase
inhibitor deficiency, Friedreich's Ataxia, and adrenal insufficiency; and
recurrent C. difficile infection (CDI). Our goal is to provide rewarding
careers to employees, to create new standards of care in the way serious
diseases are treated, and to build international partnerships with the
patients, advocates, and health care professionals we serve. ViroPharma's
commercial products address diseases including hereditary angioedema (HAE),
seizures and C. difficile-associated diarrhea (CDAD); for full U.S.
prescribing information on our products, please download the package inserts
at; the prescribing information for
other countries can be found at

ViroPharma routinely posts information, including press releases, which may be
important to investors in the investor relations and media sections of our
company's web site, The company encourages investors to
consult these sections for more information on ViroPharma and our business.

Forward Looking Statements
Certain statements in this press release contain forward-looking statements
that involve a number of risks and uncertainties. Forward-looking statements
provide the Company's current expectations or forecasts of future events.
Forward-looking statements in this press release include statements regarding
potential therapeutic indication and use, safety, efficacy, tolerability and
potential of VP20621, statements that VP20621 may prevent infection by
toxin-producing strains of C. difficile and how colonization rates may be
increased further. Our actual results could differ materially from those
results expressed in, or implied by, these forward-looking statements. The
development and commercialization of pharmaceutical products is subject to
risks and uncertainties. The safety, colonization and efficacy data described
in this press release are preliminary and additional review of the data may
reveal additional findings which may not be consistent with this press
release. The studies described in this press release represent the results of
a Phase 2 study with VP20621 and the results of the study may not be
predictive of how VP20621 will perform in future studies. There can be no
assurance that that The FDA or EMA may view the data regarding VP20621 as
insufficient or inconclusive, request additional data, require additional
clinical studies, delay any decision past the time frames anticipated by us,
limit any approved indications, or deny the approval of VP20621. There can be
no assurance that we will be successful in finding a partner to complete the
development and commercialization of VP20621. These factors, and other
factors, including, but not limited to those described in ViroPharma's annual
report on Form 10-K for the year ended December 31, 2012 and quarterly reports
on Form 10-Q filed with the Securities and Exchange Commission during 2013,
could cause future results to differ materially from the expectations
expressed in this press release. The forward-looking statements contained in
this press release are made as of the date hereof and may become outdated over
time. ViroPharma does not assume any responsibility for updating any
forward-looking statements. These forward looking statements should not be
relied upon as representing our assessments as of any date subsequent to the
date of this press release.

SOURCE ViroPharma Incorporated

Contact: ViroPharma Incorporated Contacts: Michelle M. Larkin (media),
Manager, PR & Advocacy, (610) 321- 2886,;
Robert A. Doody Jr. (investors), Director, Investor Relations, (610) 321-6290;
R. Clayton Fletcher, Vice President, Business Development, (610) 321-6789
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