HIV Digest	HIV Digest Archive

Drugs that interfere with HIV have had a major effect in reducing death and disability from AIDS. Now drug companies are beginning to test the first similar drugs for the hepatitis C virus.

HCV is now treated by a combination of alpha interferon, an immune system protein, and ribavirin. The newest versions of the combination can virtually eliminate the virus in about half of the patients. But that leaves the other half at the mercy of the virus, and with severe side effects from the treatment.

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Neither interferon nor ribavirin was specifically designed to attack HCV. Each appears to give a boost to the immune system to help it attack the virus, though scientists do not understand how they work. But the new HCV drugs entering clinical trials are designed to interfere with enzymes that HCV needs to replicate, like protease and polymerase. Similarly, the AIDS drugs interfere with two enzymes used by HIV to replicate, protease and reverse transcriptase.

It will take years to know if the new drugs will work. But scientists are encouraged by a proof of principle reported by Boehringer Ingelheim at the American Association for the Study of Liver Diseases conference in Boston in November. The company said its experimental protease inhibitor reduced viral levels by a range of a hundredfold to more than a thousandfold in a small number of patients who took the drug for only two days.

As with HIV, HCV mutates rapidly and is likely to develop resistance to drugs, so combinations of drugs will probably be needed. "It does appear with the data we have to date that it is possible to cure people with HCV, which has never been shown with HIV," said Dr. Amy Weiner, director of hepatitis C research at the Chiron Corp., the Emeryville, California, biotech company that first identified HCV.

Editor's Note: from the New York Times