Cinryze(R) (C1 Esterase Inhibitor [Human]) Data Presented at 2010 International Scientific Conference of the World Allergy Organization (WAO)

DUBAI, United Arab Emirates, December 6, 2010 - ViroPharma Incorporated (Nasdaq: VPHM) today announced data in five
poster presentations relating to Cinryze(R) (C1 esterase inhibitor [human])
at the 2010 International Scientific Conference of the World Allergy
Organization (WAO), December 5 through 8 in Dubai, UAE.

This is the first international presentation of these data, which were
first presented at the November 2010 Annual Meeting of the American College
of Allergy, Asthma & Immunology (ACAAI).

Cinryze is the first and only U.S. FDA-approved C1 esterase inhibitor
therapy indicated for routine prophylaxis against angioedema attacks in
adolescent and adult patients with hereditary angioedema (HAE), a rare,
debilitating and potentially fatal disease. Cinryze is currently available
only in the United States. Cinryze is not approved by the U.S. FDA to treat
acute angioedema attacks, nor has the safety and effectiveness of Cinryze
been established in pediatric patients with HAE. Cinryze should be used in
pregnant women only if clearly needed.

"These scientific posters mark the first international presentation of
these important data which highlight the use of Cinryze across a range of
patient populations," commented Glenn Tillotson, Ph.D., ViroPharma's head of
US medical affairs. "ViroPharma has been acknowledged as the U.S. leader in
medical education about hereditary angioedema. However, as we prepare to
expand the usage of Cinryze to other parts of the world, it is essential that
we broaden our focus, so that physicians around the globe are aware of the
severity of disease, and the importance of Cinryze as an essential option for
patients who want to gain control of their HAE attacks through prophylaxis,
rather than relying purely on acute treatment to terminate their attacks once
they have occurred. This World Congress of Allergy Scientific Congress is the
first of many such opportunities."

WAO Poster Presentations

In a poster entitled, 'Open-Label Use of Nanofiltered C1 Esterase
Inhibitor (Human) (nf-C1 INH) for Treatment or Prophylaxis of Acute Attacks
of Hereditary Angioedema (HAE) in Pregnant Subjects,' Dr. Glenn Tillotson
Ph.D., FCCP, ViroPharma Incorporated, Exton, PA, presented the experience of
14 pregnant women who were enrolled in pivotal and open label studies of
Cinryze. In this limited sample, Cinryze was utilized for the therapy of
acute attacks and as routine prophylaxis of HAE during pregnancy and
delivery. The study included the following data from 10 pregnant subjects
enrolled in the open label prophylaxis study who received a median of 34
doses of Cinryze:

    - HAE attack rates for women with pre- and post-pregnancy data improved
      when using Cinryze for prophylaxis (mean 0.25 attacks per month
      compared to a pre-Cinryze historical mean monthly attack rate of 4.25
      attacks per month; n=8);
    - Seven subjects delivered eight healthy neonates including one set of
      twins; one subject with a history of miscarriage and ectopic pregnancy
      had a spontaneous abortion, possibly as a result of an ectopic
      pregnancy; one subject who received her first exposure to Cinryze after
      the first trimester/organogenesis delivered a stillborn neonate with
      multiple congenital anomalies; and one outcome was unknown;
    - The most commonly reported adverse events during therapy in open label
      trials with pregnant subjects were infection, gastrointestinal
      disorders, and headache; no serious adverse events were considered
      related to Cinryze;
    - There was no evidence of clinically relevant anti-C1 INH antibodies;
    - There was no evidence of viral transmission.

In a poster entitled, 'Open-Label Use of Nanofiltered C1 Esterase
Inhibitor (Human) (nf-C1 INH for the Prophylaxis of Hereditary Angioedema
(HAE) Attacks,' Dr. Steven Villano, M.D., ViroPharma Incorporated, Exton, PA,
presented open label data describing the efficacy profile of Cinryze in
preventing attacks of HAE in 146 subjects with HAE. Data from this study
included the following:

    - Cinryze prophylaxis decreased the median angioedema attack rate from
      3.0 to 0.2 attacks per month;
    - In subjects treated with Cinryze prophylaxis for more than one year,
      the degree of protection from HAE attacks was maintained over time;
    - With repeat administration of Cinryze, increases in antigenic and
      functional levels of C1 inhibitor (C1-INH) post therapy were maintained
      indicating no change in systemic exposure with repeated administration;
    - No anti-C1-INH antibodies were detected during this study.
    - No subjects were discontinued from Cinryze therapy due to an adverse
      event. Headache, nausea, rash, erythema and diarrhea were the most
      frequently reported treatment-emergent Cinryze-related adverse events.

In a poster entitled, 'Open Label Use of Nanofiltered C1 Esterase
Inhibitor (Human) (nf-C1 INH) for the Treatment of Hereditary Angioedema
(HAE) Attacks,' Dr. Timothy Craig, M.D. of the Hershey Medical Center in
Harrisburg, PA, described open label data describing the results of Cinryze
in treating 609 attacks of HAE in 101 subjects with HAE. Forty-three (43)
subjects completed the study; most of those discontinuing the study did so
because they transferred to the open label prophylaxis study or commercial
Cinryze, or 3-month follow up was no longer required. Data from the study
included the following:

    - Unequivocal relief, defined as the presence of three consecutive 15
      minute assessments consistent with improvement, occurred in 68 percent
      of attacks within one hour, and 87 percent within four hours;
    - Clinical relief, defined as unequivocal relief or the presence of one
      or two consecutive 15 minute assessments consistent with improvement
      immediately prior to discharge, occurred in 73 percent of attacks
      within one hour, and 95 percent within four hours;
    - 65 percent of laryngeal attacks achieved unequivocal relief or at least
      one report consistent with improvement immediately prior to discharge
      within one hour, and 90 percent within four hours;
    - Of the 84 laryngeal attacks, none required intubation after the receipt
      of Cinryze;
    - Responses to Cinryze in subjects with more than one attack did not
      diminish with subsequent repeated administration;
    - Infusion site pain, joint swelling, rash, and sinusitis were reported
      as treatment-emergent Cinryze-related adverse events.

In a poster entitled, "Open-Label Use of Nanofiltered C1 Esterase
Inhibitor (Human) (nf-C1 INH) for Treatment of Acute Attacks of Hereditary
Angioedema (HAE) in Pediatric Subjects,' Dr. Timothy Craig, M.D. of the
Hershey Medical Center in Harrisburg, PA, presented open label experience
with Cinryze in treating 121 HAE attacks in 22 pediatric patients with HAE.
Data from this study included the following:

    - The overall median time to beginning of relief of all attacks was 15
      minutes;
    - Overall response rates within 4 hours were 89 to 97 percent for
      unequivocal relief and clinical relief, respectively;
    - No subjects with a laryngeal attack required intubation;
    - In subjects who were treated for multiple attacks, repeated therapy
      with Cinryze did not diminish the response to treatment;
    - Of the 121 acute attacks treated with Cinryze, 88 attacks were treated
      with one dose of Cinryze; 33 attacks required two doses;
    - There were no serious adverse events, and no adverse events were
      considered related to Cinryze. No subject discontinued study drug due
      to an adverse event;
    - There was no evidence of transmission of HBV, HCV, or HIV, and no
      clinically relevant anti-C1 inhibitor antibodies developed

In a poster entitled, 'Open-Label Use of Nanofiltered C1 Esterase
Inhibitor (human) (nf-C1 INH) for the Prophylaxis of Attacks of Hereditary
Angioedema (HAE) in Pediatric Subjects,' Dr. Colin Broom M.D., ViroPharma
Incorporated, Exton, PA, presented new open label results of Cinryze in
preventing HAE attacks in 23 pediatric patients with HAE. Data from this
study included the following:

    - Cinryze reduced the frequency of HAE attacks from a median of 3.0
      attacks per month at baseline to 0.39 attacks per month during Cinryze
      prophylaxis
    - In children, prophylactic doses of 1000 U of Cinryze every 3 to 7 days
      resulted in increases in antigenic and functional C1-INH levels
      comparable to those seen in adults; increases in functional C1-INH
      activity were maintained over time
    - There were no severe hypersensitivity reactions related to Cinryze; no
      discontinuations from study due to adverse events; no detectable anti-
      C1 INH antibodies; and no evidence of transmission of HBV, HCV, or HIV;
    - Adverse events considered to be possibly, probably, or definitely
      related to Cinryze were headache, nausea, and infusion site erythema,
      none of which were considered severe.

In addition, the WAO has joined with The American College of Allergy,
Asthma and Immunology (ACAAI) and the American Gastroenterological
Association (AGA) Institute in an innovative initiative called "HAE: Learn
About It, Talk About It" (www.letstalkhae.com/index.cfm). The
peer-driven campaign is designed to foster communication between physicians
on the front lines of the diagnosis and management of HAE. The addition of
WAO as a "Learn About It, Talk About It" partner expands the program to a
global audience. The program will be highlighted in booth 13 at the WAO
meeting.

About Cinryze(R) (C1 esterase inhibitor [human])

Cinryze is a highly purified, pasteurized and nanofiltered plasma-derived
C1 esterase inhibitor product that has been approved by U.S. FDA for routine
prophylaxis against angioedema attacks in adolescent and adult patients with
HAE. C1 inhibitor therapy has been used acutely for more than 35 years in
Europe to treat patients with C1 inhibitor deficiency.

Severe hypersensitivity reactions to Cinryze may occur. Thrombotic events
have occurred in patients receiving Cinryze for routine prophylaxis, 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 observed
have been upper respiratory infection, sinusitis, rash and headache. No
drug-related serious adverse events (SAEs) have been observed in clinical
trials.

Cinryze is for intravenous use only. A dose of 1000 Units of Cinryze can
be administered every 3 or 4 days for routine prophylaxis against angioedema
attacks in HAE patients. Cinryze is administered at an injection rate of 1 mL
per minute.

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 in the United States.

For more information on HAE, visit the U.S. HAE Association's website at:
www.haea.org, and the International HAE Association's website at:
www.haei.org.

About ViroPharma Incorporated

ViroPharma Incorporated is an international biopharmaceutical company
committed to developing and commercializing innovative products for physician
specialists to enable the support of patients with serious diseases for which
there is an unmet medical need, and providing rewarding careers to employees.
ViroPharma commercializes Cinryze(R) (C1 esterase inhibitor [human]) for
routine prophylaxis against angioedema attacks in adolescent and adult
patients with hereditary angioedema (HAE). ViroPharma commercializes
Vancocin(R), approved for oral administration for treatment of
antibiotic-associated pseudomembranous colitis caused by Clostridium
difficile and enterocolitis caused by Staphylococcus aureus, including
methicillin-resistant strains (for prescribing information on ViroPharma's
commercial products, please download the package inserts at
www.viropharma.com/Products.aspx). ViroPharma currently focuses its
drug development activities in diseases including C1 esterase inhibitor
deficiency and C. difficile infection.

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.
There can be no assurance that that the data presented during the 2010
International Scientific Conference of the World Allergy Association (WAO)
regarding Cinryze is predictive of how Cinryze will perform in commercial
usage. Cinryze is currently available only in the United States. Cinryze is
not approved in the U.S. for acute treatment of attacks nor has the safety
and effectiveness of Cinryze been established in pediatric patients with HAE.
We cannot assure that current or future studies with Cinryze in the patient
populations described in the WAO presentations may demonstrate the safety and
efficacy profile of Cinryze. The EMA may view the data regarding the use of
Cinryze for acute treatment and / or prevention of HAE we have submitted in
the MAA 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, deny the approval of
Cinryze for acute treatment and / or prevention of HAE or approve a competing
product which has been granted orphan drug designation thereby preventing
Cinryze from reaching the European market. For example, in June 2009, the
U.S. FDA issued a complete response letter and requested an additional
clinical study, due to their opinion that the placebo controlled study
submitted in support of the sBLA for acute treatment of HAE lacked
robustness. 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, 2009 and 10-Q filings for the quarters ended March 31, 2010, June 30,
2010 and September 30, 2010 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.

Kristina M. Broadbelt (Media), Assistant Director, PR & Advocacy, +1-610-321-2358, or Robert A. Doody Jr. (Investors), Assistant Director, Investor Relations, +1-610-321-6290