Scientific Data Relating to Cinryze(TM) Presented at 6th Annual C1 Inhibitor Deficiency...

Scientific Data Relating to Cinryze(TM) Presented at 6th Annual C1 Inhibitor
Deficiency Workshop

BUDAPEST, Hungary and EXTON, Pa., May 26 /PRNewswire-FirstCall/ -- ViroPharma
Incorporated (Nasdaq: VPHM) today announced the presentation of five abstracts
relating to Cinryze(TM) (C1 esterase inhibitor [human]) therapy at the 6th
Annual C1 Inhibitor Deficiency Workshop.

Cinryze was approved by the U.S. Food and Drug Administration in October 2008
for routine prophylaxis against hereditary angioedema (HAE) attacks in adults
and adolescents. In February 2009, ViroPharma was granted priority review of a
supplemental Biologics License Application for Cinryze for the treatment of
acute attacks of HAE. If approved, Cinryze would be the first C1 esterase
inhibitor available for the acute treatment for this condition. ViroPharma's
PDUFA date for Cinryze in the acute setting is June 3, 2009.

"With the C1 Inhibitor Deficiency Workshop presentations focusing on items
including HAE treatment considerations and the potential for subcutaneous
infusion, among others, ViroPharma is demonstrating our commitment to meeting
the needs of patients with C1 deficiency diseases today, and tomorrow,"
commented Glenn Tillotson, ViroPharma's senior director and head of Medical
Affairs.

The following abstracts from studies supported by Lev Pharmaceuticals, a
company acquired by ViroPharma Incorporated in October 2008, were presented:

Abstract book page 27: Prophylactic Therapy Considerations in Hereditary
Angioedema
-- In an abstract entitled, 'When Should Prophylactic Therapy be
Considered for Hereditary Angioedema?', Dr. Tim Craig, et al.
described how a literature review, guideline analysis from other
countries, expert panel meeting, and consensus development were
conducted in order to develop therapy considerations for prophylaxis
of
HAE in the U.S.;
-- The abstract suggested that patients with frequent HAE attacks, severe
attacks, past laryngeal attacks, excessive loss of work or school,
significant anxiety and poor quality of life could be considered for
prophylaxis therapy, especially for those that fail, are intolerant,
have adverse events or are not candidates for androgens;

-- This abstract was the result of a consensus group on the treatment
considerations for patients with HAE, which was paid for and organized
by Lev Pharmaceuticals.

Abstract book page 46: Subcutaneous Infusion of Cinryze in Pigs
-- From the laboratory of Dr. Michael Frank at Duke University, Dr. H.
Jiang et al. described the results of a comparative pharmacokinetic
study of subcutaneous and intravenous doses of C1 Inhibitor in an
abstract entitled, 'Subcutaneous (SQ) Versus Intravenous (IV)
Infusion of C1 Inhibitor (INH) on Blood Levels in Swine';

-- In this study, 50 units/kg of human C1 inhibitor were infused either
IV
or SQ into swine. Blood levels of C1 inhibitor after IV infusion were
compared to that after SQ infusion; animals received 3 infusions of C1
inhibitor at 3 day intervals, as in an earlier study of IV infusion in
HAE patients.

Abstract book page 47: The Effect of Cinryze on Key Pathways in HAE
-- As described in an abstract entitled, 'Infusion of C1 Inhibitor as
Therapy for Swelling in Hereditary Angioedema Patients Reverses
Abnormalities of the Plasma Bradykinin-forming Pathway and
Fibrinolysis,' Dr. K. Joseph et al. described a study of samples of
plasma from nine HAE patients experiencing an attack in
ViroPharma/Lev's Phase 3 CHANGE (C1 inhibitor in Hereditary
Angioedema Nanofiltration Generation evaluating Efficacy) trial;
-- Samples of plasma were obtained from nine HAE patients at baseline,
during an attack of swelling, and at one, four and 12 hours after
termination of an infusion of C1 inhibitor;

-- Factor XIIa, kallikrein and plasmin were each measured by cleavage of
specific synthetic substrates; these parameters were reassessed after
treatment of episodes of swelling with intravenous C1 inhibitor.

Abstract book page 37: Phase 3 Results of Cinryze as Prophylactic and Acute
Treatment of HAE
-- In an abstract entitled, 'Safety and Efficacy of Nanofiltered C1
Inhibitor Concentrate for Acute and Prophylactic Treatment of
Hereditary
Angioedema due to C1 Inhibitor Deficiency,' Dr. M. Frank described
two double-blind randomized placebo-controlled multi-center studies to
determine the efficacy and safety of nanofiltered C1 inhibitor
(C1-INH;
Cinryze);
-- This is the first presentation of both acute and prophylactic data of
Cinryze. One trial examined the use of C1-INH for the treatment of
acute
attacks of hereditary angioedema due to C1 inhibitor deficiency. The
second trial evaluated prophylactic treatment with C1-INH to prevent
attacks;

-- Cinryze is not approved for acute attacks of HAE.

Abstract book page 18:Cinryze in Pregnant Women
-- An abstract entitled, 'Cinryze Replacement Therapy in Hereditary
Angioedema and Pregnancy' was presented by Dr. J.W. Baker et al.;
-- Pregnancy is recognized as a trigger for attacks of HAE, and may
increase the number and severity of such attacks. Cinryze should be
given to a pregnant woman only if clearly needed;
-- Six patients received 1000U of Cinryze replacement therapy 1-2 times
per
week as prophylaxis of HAE attacks during pregnancy. One patient self
administered Cetor, a Dutch C1 inhibitor product, after the first two
trimesters. An additional patient received Cinryze 1000U immediately
prior to delivery and again two days later;

-- Data on side effects, frequency of HAE attacks, and number of
emergency
medical visits prior to and following initiation of Cinryze therapy
were
presented.

About Cinryze C1 Esterase Inhibitor (human)
Cinryze is a highly purified, pasteurized and nanofiltered plasma-derived C1
esterase inhibitor product that has been approved by 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.

Cinryze has been generally well tolerated. 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. Severe hypersensitivity reactions may occur. Thrombotic events have
occurred in patients receiving high dose off-label C1 inhibitor therapy well
above the approved treatment dosage regimen. 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 patients for prior exposure to certain virus infections and by
manufacturing steps to reduce the risk of viral transmission including
pasteurization and nanofiltration.

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 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 unrestricted, 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 6000 people with
HAE in the United States.

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

About ViroPharma Incorporated
ViroPharma Incorporated is a biopharmaceutical company dedicated to the
development and commercialization of products that address serious diseases
treated by physician specialists and in hospital settings. ViroPharma
commercializes Vancocin(R) (vancomycin hydrochloride capsules, USP), 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, and
Cinryze(TM) (C1 esterase inhibitor [human]) for routine prophylaxis against
angioedema attacks in adolescent and adult patients with hereditary angioedema
(HAE), also known as C1 inhibitor deficiency (for prescribing information on
ViroPharma's commercial products, please download the package inserts at
http://www.viropharma.com/Products.aspx). ViroPharma currently focuses its
drug development activities in diseases including cytomegalovirus (CMV), HAE
and C. difficile.

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 the Company's current expectations or forecasts of future events.
Forward-looking statements in this press release include statements regarding
ViroPharma's supplemental Biologics License Application for Cinryze for the
treatment of acute attacks of HAE and the potential for subcutaneous infusion.
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 data that were submitted to the U.S. Food and Drug
Administration include data from two separate studies including the pivotal
Phase 3 study of Cinryze in acute HAE attacks and the ongoing open-label study
of Cinryze for acute treatment of HAE, which includes partial data from an
ongoing open label study. There can be no assurance that the complete data
from the open label study will demonstrate that Cinryze successfully treats
all types of acute hereditary angioedema (HAE) attacks and may not be
predictive of the results of any future testing. The FDA may view the data
regarding the use of Cinryze for acute treatment of HAE we have submitted as a
supplemental BLA as insufficient or inconclusive, not accept our submission,
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 of HAE or
approve a competing product which has been granted orphan drug designation
thereby preventing Cinryze from reaching the market for acute treatment of
HAE. We have not conducted any human studies related to the subcutaneous
infusion of Cinryze and there can be no assurance that any future studies will
demonstrate that subcutaneous infusion of Cinryze is safe or effective or that
a subcutaneous formulation of Cinryze will receive regulatory approval. These
factors, and other factors, including, but not limited to those described in
ViroPharma's annual report on Form 10-K and quarterly reports on Form 10-Q
filed with the Securities and Exchange Commission during 2009, could cause
future results to differ materially from the expectations expressed in this
press release. The forward-looking statements contained in this press release
may become outdated over time. ViroPharma does not assume any responsibility
for updating any forward-looking statements.

SOURCE ViroPharma Incorporated

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