Varying Combinations Of Antiviral Drugs May Effectively Treat Chronic Hepatitis Virus Infection In Woodchucks

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http://www.sciencedaily.com/releases/2008/10/081016133509.htm

Varying Combinations Of Antiviral Drugs May Effectively Treat Chronic Hepatitis

Virus Infection In Woodchucks

ScienceDaily (Oct. 20, 2008) — Oral administration of various combined and

independent antiviral drug therapies may effectively treat chronic hepatitis B

virus (HBV) infection in woodchucks, a well-characterized mammalian model for

research with human implications, and provide an alternative strategy for

managing drug resistance.

The researchers from Cornell University, Ithaca, New York; Gilead Sciences,

Durham, North Carolina; and town University Medical Center, Washington, DC

report their findings in the October 2008 issue of the journal Antimicrobial

Agents and Chemotherapy.

Chronic infection with HBV is responsible for 1.2 million annual deaths

worldwide. Statistics also show that 2 billion people currently or previously

suffered from infection while 350 million people are chronic carriers of HBV and

are at risk of developing chronic hepatitis, hepatic cirrhosis, and

hepatocellular carcinoma. Preventative vaccines are currently offered, however,

side effects and drug resistance are limiting the efficacy of available

treatment therapies.

In the study researchers evaluated the antiviral effects of orally administered

adefovir dipivoxil (ADV) or tenofovir disoproxil fumarate (TDF) alone or in

combination with lamivudine (3TC) or emtricitabine (FTC) in woodchucks with

chronic hepatitis virus infection. Initial results showed once daily treatment

for 48 weeks with ADV plus 3TC or TDF plus FTC greatly reduced viral levels from

those pretreatment. Additional treatment with TDF plus 3TC, ADV alone, ADV plus

FTC, TDF alone, 3TC alone, and FTC alone showed pronounced declines in viral

levels in all groups. Following drug withdrawal most woodchucks displayed

renewed hepatitis virus replication, but some did experience sustained effects.

Lastly, no toxicity was observed following administration of any of the drugs or

drug combinations.

" In conclusion, the oral administration of 3TC, FTC, ADV, and TDF alone and in

combination was safe and effective in the woodchuck model of HBV infection, " say

the researchers.

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Journal reference:

S. Menne, S.D. Bulter, A.L. , I.A. Tochkov, Y. Zhu, S. Xiong, J.L. Gerin,

P.J. Cote, B.C. Tennant. Antiviral Effects of Lamivudine, Emtricitabine,

Adefovir Dipivoxil, and Tenofovir Disoproxil Fumarate Administered Orally Alone

and in Combination to Woodchucks with Chronic Woodchuck Hepatitis Virus

Infection. Antimicrobial Agents and Chemotherapy, 2008; 52 (10): 3617 DOI:

10.1128/AAC.00654-08

Adapted from materials provided by American Society for Microbiology, via

EurekAlert!, a service of AAAS.