ViroPharma's Cinryze® (C1 Esterase Inhibitor [Human]) Prophylaxis Study Showed Safety Data of Escalating Doses in Patients With

ViroPharma's Cinryze® (C1 Esterase Inhibitor [Human]) Prophylaxis Study Showed
    Safety Data of Escalating Doses in Patients With Hereditary Angioedema

- Safety and Efficacy of Escalating Doses Presented at the 2012 Annual Meeting
of the American College of Allergy, Asthma and Immunology (ACAAI) -

PR Newswire

EXTON, Pa., Nov. 13, 2012

EXTON, Pa., Nov. 13, 2012 /PRNewswire/ -- ViroPharma Incorporated (Nasdaq:
VPHM) today announced important data from an open-label, multicenter study to
assess the safety, tolerability, and treatment effect of escalating doses of
C1 INH-nf in patients with HAE who were not adequately controlled with 1000 U
every 3 or 4 days. The results of this study were presented at the 2012 annual
meeting of the American College of Allergy, Asthma and Immunology (ACAAI) in
Anaheim, California. The data provide evidence for the safety profile of
Cinryze^® (C1 esterase inhibitor [human]) at doses up to 2500 units in
patients with hereditary angioedema (HAE). HAE is a rare, severely
debilitating, life-threatening genetic disorder caused by a deficiency of a
human plasma protein called C1 inhibitor. The presentation titled, Safety and
Efficacy of Escalating Doses of C1 Esterase Inhibitor [Human] (Cinryze) as
Prophylaxis in Patients with Hereditary Angioedema (HAE) was presented  by Dr.
Jonathan A. Bernstein from the University of Cincinnati. The study was a post
marketing FDA requirement to assess the safety and tolerability of escalating
doses of Cinryze, with specific interest in thrombogenicity and
immunogenicity.

This study enrolled 20 eligible subjects over a 3 year period. Subjects with
qualifying HAE attack rates, and who met other specified entry criteria, were
entered into a 3-step dose-escalation algorithm. Each step consisted of
12weeks of sequential Cinryze dose escalation of 1500, 2000, and 2500 units
with infusions every 3 or 4 days if the subject continued to have an average
of >1.0 angioedema attacks/month, regardless of severity. An additional 3
month safety follow-up occurred with successful completion of a dose
escalation step. The authors concluded that doses up to 2500 units every 3 or
4 days may be considered for patients who do not respond to 1000 units twice
weekly. The results of the study showed that:

  oOverall, the safety profile of Cinryze doses up to 2500 units was
    consistent with previous clinical trial experience at lower doses;
  oNo systemic thrombotic events occurred during this study;
  oAt all dosage levels, Cinryze was well tolerated, with no discontinuations
    due to an adverse event (AE);
  oThe majority of AEs were mild to moderate intensity;
  oDuring the 12 month study, 2 patients experienced AEs that the
    investigator considered to be related to study medication (1 with
    localized blood clot in a port-a-cath on Day 81 treated with
    streptokinase, catheter-site pain on first day of dosing of two dose
    escalation steps, and dyspnea on Day 173 and 1 with muscle spasm);
  oTwo patients experienced serious adverse events unrelated to study
    medication (one with cerebral cystic lymphangioma and one with worsening
    anemia and bile duct stone);
  oIn one patient, C1 INH antibodies were detected at baseline (pre-dose Day
    1) and in all samples collected during the study while receiving doses up
    to 2500 units. Another patient developed borderline detectable antibodies
    to C1 inhibitor while receiving 2500 units of study drug.

"The study analysis of these data provides insight into the safety and
efficacy of dose escalation of Cinryze up to 2500 units," commented Dr.
Jonathan A. Bernstein, professor of clinical medicine, Department of Internal
Medicine, University of Cincinnati Medical Center, "Previous Cinryze studies
show that patients had reductions in the frequency, severity, and duration of
angioedema attacks while receiving 1000 units; however, some patients were not
adequately controlled at this dose. We are pleased to see that higher doses of
Cinryze do not result in systemic thrombotic events, and may be considered for
patients with HAE who do not respond to lower doses."

About Cinryze^® (C1 esterase inhibitor [Human])

Cinryze is a highly purified, pasteurized and nanofiltered plasma-derived C1
esterase inhibitor product. In the U.S., Cinryze is approved by the FDA for
routine prophylaxis against angioedema attacks in adolescent and adult
patients with HAE. In the E.U., the product is approved by the EMA for the
treatment and pre-procedure prevention of angioedema attacks in adults and
adolescents with hereditary angioedema (HAE), and routine prevention of
angioedema attacks in adults and adolescents with severe and recurrent attacks
of hereditary angioedema (HAE), who are intolerant to or insufficiently
protected by oral prevention treatments or patients who are inadequately
managed with repeated acute treatment. Cinryze is for intravenous use only.

Severe hypersensitivity reactions to Cinryze may occur. Thrombotic events
have occurred in patients receiving Cinryze, and in patients receiving
off-label high dose C1 inhibitor therapy. Monitor patients with known risk
factors for thrombotic events. With any blood or plasma derived product,
there may be a risk of transmission of infectious agents, e.g. viruses and,
theoretically, the CJD agent. The risk has been reduced by screening donors
for prior exposure to certain virus infections and by manufacturing steps to
reduce the risk of viral transmission including pasteurization and
nanofiltration.

The most common adverse reactions in clinical trials associated with Cinryze
were rash, headache, nausea, erythema, phlebitis and local reactions at the
injection site. Adverse events of sinusitis and upper respiratory infection
also were observed in clinical trials. No drug-related serious adverse events
(SAEs) were reported in clinical trials.

Please visit http://www.viropharma.com/products/cinryze.aspx for the full U.S.
Prescribing Information; the prescribing information for other countries can
be found at www.viropharma.com.

About Hereditary Angioedema (HAE)

HAE is a rare, severely debilitating, life-threatening genetic disorder caused
by a deficiency of C1 inhibitor, a human plasma protein. This condition is the
result of a defect in the gene controlling the synthesis of C1 inhibitor. C1
inhibitor maintains the natural regulation of the contact, complement, and
fibrinolytic systems, that when left unregulated, can initiate or perpetuate
an attack by consuming the already low levels of endogenous C1 inhibitor in
HAE patients. Patients with C1 inhibitor deficiency experience recurrent,
unpredictable, debilitating, and potentially life threatening attacks of
inflammation affecting the larynx, abdomen, face, extremities and urogenital
tract. Patients with HAE experience approximately 20 to 100 days of
incapacitation per year. There are estimated to be at least 6,500 people with
HAE inthe United Statesand at least 10,000 people in theEuropean Union.

For more information on HAE, visit the U.S. HAE Association's website
atwww.haea.organd the HAEi's (International Patient Organization for C1
Inhibitor Deficiencies) website atwww.haei.org.

AboutViroPharma 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,
cytomegalovirus (CMV); 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, adrenal insufficiency and C. difficile-associated
diarrhea (CDAD); for full U.S. prescribing information on our products, please
download the package inserts at http://www.viropharma.com/Products.aspx; the
prescribing information for other countries can be found at
www.viropharma.com.

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, www.viropharma.com. 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 our current expectations or forecasts of future events.. Our actual
results may vary significantly from these forward-looking statements. The
commercialization of pharmaceutical products is subject to risks and
uncertainties. The data that were discussed at the ACAAI meeting are subject
to different interpretations and may not be predictive of the results of any
individual's results or of how Cinryze performs in commercial usage. These
factors, and other factors, including, but not limited to those described in
our annual report on Form 10-K for the year ended December 31, 2011 and 10-Q
filings for the quarters ended March 31, 2012, June 30, 2012, and September
30, 2012 filed with the Securities and Exchange Commission, 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

Website: http://www.viropharma.com
Contact: ViroPharma Media Contacts: Kristina M. Broadbelt, Associate Director,
PR & Advocacy, +1-610-321-2358, Shannon M. Sanders, Manager, Global PR &
Advocacy, +1-610-321-2886, ViroPharma Investor Contact: Robert A. Doody,
Assistant Director, Investor Relations, +1-610-321-6290
 
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