SAN DIEGO--(BUSINESS WIRE)--02/19/2004--Anadys Pharmaceuticals
initiates Phase I clinical trial of
isatoribine prodrug for study as a hepatitis C therapy

Anadys Pharmaceuticals, Inc. ("Anadys") announced today that it
has initiated a clinical trial of ANA971, an orally administered
prodrug of isatoribine. Isatoribine is a nucleoside analog in
development for the treatment of chronic hepatitis C virus (HCV)
infection. To date, isatoribine has been administered to 48
subjects, including 28 patients chronically infected with HCV. A
recent clinical study showed that intravenous administration of
isatoribine was well tolerated and safe at all doses tested.
Interim results from that study have also shown preliminary
biological activity and viral load reduction in the patient
populations whose clinical data has been completed and analyzed.
ANA971, which was discovered by Anadys, is a prodrug designed to
improve the oral bioavailability of isatoribine. Anadys has
exclusive rights to market and commercialize isatoribine and ANA971
worldwide.

In preclinical animal studies, oral administration of ANA971
resulted in higher levels of isatoribine in the blood than were
present after oral administration of isatoribine itself. The
objectives of this clinical trial are to assess safety and
pharmacokinetics in healthy volunteers following oral
administration of ANA971.

"Initiation of this clinical trial represents another important
step toward our goal of improvement of HCV patient care, and builds
on the results of clinical work we have conducted with
isatoribine," said Devron Averett, Ph.D., Senior Vice President of
Drug Development for Anadys.
About isatoribine (ANA245)

Isatoribine is a nucleoside analog Anadys is evaluating in
ongoing clinical trials for the treatment of HCV infections.
Isatoribine represents one of a new class of drugs being developed
by Anadys to regulate innate immunity, combat HCV infection, and
overcome limitations of current anti-HCV therapies. Anadys believes
isatoribine interacts with a specific receptor, Toll-like receptor
7, or TLR7, that is present on certain immune system cells.
Although results of initial clinical trials may not be predictive
of future results, interim results of the Phase 1B clinical trial
show that isatoribine is biologically active in adults with chronic
HCV infection and results from dosing a cohort of six HCV infected
patients with 800mg of isatoribine showed a statistically
significant reduction of viral load (p=0.03) at the end of one
week, with a median change in viral load from baseline of -0.94
log10 units(a). Anadys is currently enrolling patients for an
isatoribine Phase I/II study.

About hepatitis C

HCV causes inflammation of the liver and degradation of liver
function. HCV infection is currently the most common chronic
blood-borne infection in the United States. Approximately 2.7
million people in the United States are chronically infected with
HCV, and it causes 10,000 to 12,000 deaths a year in the United
States. The Centers for Disease Control and Prevention, or CDC,
estimates the annual mortality rate in the United States could
increase to 38,000 by the year 2010, surpassing the number of
deaths attributed annually to HIV/AIDS. HCV is transmitted
primarily through significant or repeated exposures to infected
blood. Approximately two thirds of new infections progress to
chronic infection. Chronic HCV infection may also progress to more
serious complications such as cirrhosis of the liver, liver cancer,
and death.
For more information, please visit
www.anadyspharma.co

(a) Note to editors: In the value -0.94 log10 units, the 10 in
log10 should be subscript.

CONTACT:Anadys Pharmaceuticals, Inc. Vice-President, Corporate
Development and Strategy Michael Kamdar, 858-530-3667
cc@... or Atkins & Associates Sr. Vice President Carin
Canale, 858-527-3498 ccanale@...