One of the biggest obstacles to treatment for people with hepatitis C is that the drugs that we have now – pegylated interferon and ribavirin – just aren’t that good. They have a range of potentially severe and even life-threatening side effects that deter a lot of people from seeking treatment, especially people with a history of depression, which can be brought on or worsened by interferon. And they don’t work for everybody: treatment only results in long-term clearance of the virus (a sustained virologic response, where hepatitis C is undetectable six months after ending treatment) about half the time. Chances of success are lower for many groups, including African-Americans, people co-infected with HIV, and those with genotype 1 – the most common strain of hepatitis C in the U.S. (for two good fact sheets explaining hepatitis C genotype see Genotype from the Easy C Facts Series by the Hepatitis C Support Project/HCV Advocate and also HCV genotypes from the Hepatitis C Council of New South Wales in Australia -- both fact sheets are PDF files). Furthermore interferon needs to be injected – a big disincentive for a lot of people, particularly former drug injectors wary of relapse. All of which adds up to a compelling need for new drugs.
That’s why research presented a year and a half ago at the annual meeting of the American Association for the Study of Liver Diseases (AASLD) sent ripples of excitement and hope throughout the hepatitis C community. Researchers from Boehringer Ingelheim (BI) presented dramatic data on a brand new drug, BILN 2061. BILN 2061 is the first drug successfully tested in humans that specifically targets the hepatitis C protease (technically, the NS3 serine protease), an enzyme essential for making new copies of the virus. BILN 2061 is a protease inhibitor: it binds to the active site of the NS3 serine protease, blocking its action and shutting down viral replication.
People in the studies took BILN 2061 for two days and saw their hepatitis C viral load drop by over 100-fold (for instance, from 2 million copies to less than 20,000 copies) before returning to original levels within a week. A couple people saw their hepatitis C viral load fall by 1,000 fold (e.g., from 2 million down to 2,000). These initial results were astonishing; in the words of Dr. Charles Rice, a prominent researcher who directs the Center for the Study of Hepatitis C in New York, “sort of a hush fell over the audience” (quoted in “H.I.V. Lessons Used in Hepatitis C Treatment” by Andrew Pollack, New York Times, 3/11/03, section F, page 6).