What is the relevance of genotype in the management of hepatitis C?
David Bernstein MD: Genotype testing is probably one of the most important tests that can be obtained in evaluating and treating someone with chronic hepatitis C. There are numerous genotypes that we see; most commonly in the United States, genotype 1, which makes up approximately 75% of the population who have hepatitis C. Genotypes 2 and 3 make up 99% of the remainder, with scattered pockets throughout the country of genotypes 4, 5 and 6. The importance of genotype testing is that it enables us to determine what therapy to use and, in some newer studies, for how long. What I mean by that is that in the studies that looked at standard three-times-a-week interferon-alpha-2b plus ribavirin – patients could be treated for a six-month period of time with ribavirin, either a gram or 1200 mg, and had an approximate 65% sustained response rate with six months of therapy. That short a course of therapy with such improved response rate, which is actually equivalent to that seen at 12 months, l
