ViroPharma Licenses Rights from GlaxoSmithKline for Product Cand

    ViroPharma Licenses Rights from GlaxoSmithKline for Product
     Candidate for Cytomegalovirus (CMV) in Immunocompromised
    Published Data Support Progression to Phase 1 / 2 Clinical
                    Trials in Patients with CMV

EXTON, Pa., Aug. 11, 2003 (PRIMEZONE) -- ViroPharma Incorporated
(Nasdaq:VPHM) today announced the acquisition of worldwide rights
(excluding Japan) from GlaxoSmithKline (GSK) to an antiviral compound,
maribavir (1263W94), for the treatment of human cytomegalovirus (HCMV)
disease. Maribavir (1263W94) is a benzimidazole compound that was in
development by GSK for the treatment of CMV retinitis in HIV+ patients.
Initial Phase 1 data in HIV+ patients demonstrated an antiviral effect
and an acceptable safety profile sufficient to support progression of
the development of the compound. ViroPharma will focus initially on
patients who have received a hematopoietic stem cell (e.g., bone
marrow) or solid organ transplant, and are at risk for or have been
infected with CMV. ViroPharma expects to initiate phase 1 / 2 clinical
trials in transplant patients in the fourth quarter of 2003 or the
first quarter of 2004. 
Under the terms of the agreement, ViroPharma has exclusive worldwide
rights (excluding Japan) to develop and commercialize maribavir
(1263W94), for the prevention and treatment of cytomegalovirus
infections related to transplant (including solid organ and
hematopoietic stem cell transplantation), congenital transmission, and
in patients with HIV infection. ViroPharma paid GSK a $3.5 million
up-front licensing fee and will pay additional milestones based upon
defined clinical development and regulatory events. The company also
will pay royalties to GSK and its licensor on product sales in the
United States and rest of world (excluding Japan). 
"Given that the incidence of CMV infection in transplant patients is
substantial, there clearly exists a need for antiviral medicines that
are both safe and effective against CMV in order to reduce the risk to
these patients," said Stephen Villano, M.D., ViroPharma's director of
clinical research. "What gives us confidence to advance the compound
into phase 1 / 2 clinical trials is that previously published clinical
data for this compound in HIV-infected men demonstrated antiviral
activity, oral bioavailability and a safety and tolerability profile
that supports its continued development. This makes the compound
attractive to ViroPharma as a potential anti-CMV product. Further, this
opportunity fits well with ViroPharma's commercial strategy to address
well defined markets." 
Maribavir (1263W94 Data) 
Maribavir is a benzimidazole compound being studied for the prevention
and treatment of cytomegalovirus (CMV) infections. To date, maribavir
has been administered orally to 100 human subjects in several Phase 1
studies. In the largest of these studies, 78 HIV-infected men with
asymptomatic CMV shedding received one of six different dosage regimens
of oral maribavir or placebo for 28 days. Maribavir was rapidly
absorbed and demonstrated dose-proportional exposure with increasing
doses. Based on mean reductions of 2.9 to 3.7 log(10) concentrations of
CMV as measured in semen using a plaque assay, in vivo anti-CMV
activity was evident at all of the dosage regimens tested. Maribavir
was generally well tolerated in this study; taste disturbance was the
most frequently reported adverse event. Results from this study were
published in an article entitled, "Phase I dose escalation trial
evaluating the pharmacokinetics, anti-human cytomegalovirus (HCMV)
activity, and safety of 1263W94 in human immunodeficiency
virus-infected men with asymptomatic HCMV shedding," Lalezari JP, Aberg
JA, Wang LH, et al. Antimicrob Agents Chemother 2002; 46:2969-2976. 
HCMV Overview 
Human Cytomegalovirus, or HCMV, is a member of the herpes virus group,
which includes the viruses that cause chicken pox, mononucleosis and
herpes simplexes 1 and 2. Like other herpesviruses, HCMV has the
ability to remain dormant in the body for long periods of time. Human
CMV infection rates average between 50% and 85% of adults in the U.S.
by 40 years of age. In most individuals with intact immune systems, CMV
causes little to no apparent illness. However, in immunocompromised
individuals, CMV can lead to serious disease or death. Before the
availability of potent anti-HIV therapy, CMV associated retinitis was
commonly seen in patients with HIV/AIDS. Currently, patients who are
immunosuppressed following hematopoietic stem cell (e.g., bone marrow)
or solid organ transplantation remain at high risk of CMV infection. In
these patients, CMV can lead to severe conditions such as pneumonitis
or hepatitis, or to complications such as acute or chronic rejection of
a transplanted organ. 
About ViroPharma Incorporated 
ViroPharma Incorporated is committed to the commercialization,
development and discovery of antiviral pharmaceuticals. ViroPharma
plans to initiate Phase 1 / 2 clinical trials in cytomegalovirus (CMV)
during the fourth quarter of 2003 or the first quarter of 2004, and
Phase 1 clinical trials in hepatitis C virus (HCV) in the first quarter
of 2004. ViroPharma also is considering the development of an
intranasal formulation of Picovir(r) for the treatment of the common
cold and the development of Picovir(r) to treat patients suffering from
severe or life-threatening enteroviral infections, and has a
bioterrorism and emerging virus disease drug discovery and development
This press release contains forward-looking statements, including those
relating to ViroPharma's plan to advance maribavir initially for the
prevention and treatment of CMV infection in transplant patients, and
the company's plans to initiate Phase 1 / 2 clinical trials in
transplant patients in the fourth quarter of 2003 or the first quarter
of 2004 and to initiate Phase 1 clinical studies in HCV in the first
quarter of 2004. The clinical development of investigational
pharmaceutical products is subject to risks and uncertainties. There
can be no assurance that ViroPharma's studies of any of its product
candidates can be conducted within the timeframe that the company
expects, or that such studies will yield positive results. Also, the
Phase 1 data of maribavir in HIV-infected patients with CMV are not
necessarily predictive of maribavir's safety or efficacy in the
transplant patients. These and other factors, including, but not
limited to those described in ViroPharma's most recent annual report on
Form 10-K 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 may become outdated over time.
ViroPharma does not assume any responsibility for updating any
forward-looking statements. 

CONTACT:  ViroPharma Incorporated
          Kori Beer
          Director, Corporate Communications
          Phone 610 321-6288

 Provider ID: 00043694
-0- Aug/11/2003 11:30 GMT
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