for previously untreated patients the optimal treatment is combined pegylated interferon and ribavirin (rebetol copegus). patients who have reasons not to receive ribavirin may be treated solely with pegylated interferon. older preparations of interferon are less effective and less commonly used. pegylated interferon interferons are a family of naturally occurring proteins produced by the body to fight viral infections. to produce pegylated interferon the interferon is processed by attaching ethylene glycol to it. this process is called pegylation and it slows the elimination of interferon from the body so that its effects are more prolonged. there are currently two types of pegylated interferon: pegylated interferon alpha 2b (peg-intron a) and pegylated interferon alpha 2a (pegasys). both pegylated interferon alpha 2b and 2a are given as a subcutaneous injection once a week. optimally pegylated interferon therapy should be combined with ribavirin. in persons who cannot take ribavirin monotherapy with pegylated interferon may be used. monotherapy has been shown to achieve sustained virologic response rates of 23% to 25% in patients. ribavirin the antiviral agent ribavirin (rebetol copegus) is a nucleoside analogue that is taken by mouth. nucleoside analogues are man-made molecules that closely resemble the biochemical units that make up genetic material (rna and dna). ribavirin works by fooling the virus into using it instead of the normal building blocks thereby slowing viral reproduction. ribavirin has not worked well when used alone for hepatitis c. combined pegylated interferon and ribavirin combined therapy with both pegylated interferon and ribavirin produces a sustained virologic response in 28% to 50% of patients with genotype 1. for unknown reasons response rates are lower in african american persons and higher in white persons. in patients with genotype 2 sustained response rates are higher (76% to 82%). the duration of therapy depends on the genotype of the hcv. hence the recommended duration of treatment for hcv genotypes 2 and 3 is 24 weeks and for genotype 1 is 48 weeks. sustained virologic response usually is accompanied by a return to normal serum alt levels and improvement in inflammation within the liver. combination therapy is associated with more side effects than monotherapy. in research studies up to 20% of patients receiving combination therapy required a reduction in the doses or discontinuation of therapy because of the side effects. nevertheless combination therapy represents significant progress in the treatment of chronic hcv and is the current standard of care. some patients treated successfully with combination therapy still have detectable virus after 12 weeks of treatment but go on to have a sustained response. therefore patients on combination therapy should have hepatitis c virus rna measured at 24 weeks of therapy. in those who are still positive for the virus at that time consideration is given to stopping treatment since the chance of sustained response is small.
what are the therapy options for previously untreated patients with chronic hepatitis c?