Telaprevir, a specific inhibitor of the HCV serine protease, was evaluated in combination with peginterferon alfa-2a and ribavirin for chronic HCV genotype 1 infection. In a phase 2 trial, 334 patients were randomly assigned to four treatment groups: T12PR24 (telaprevir, peginterferon, ribavirin for 12 weeks, followed by peginterferon and ribavirin for 12 weeks), T12PR12 (telaprevir, peginterferon, ribavirin for 12 weeks), T12PR12 (telaprevir and peginterferon without ribavirin for 12 weeks), and PR48 (peginterferon and ribavirin for 48 weeks). The primary endpoint was a sustained virologic response (SVR), defined as undetectable HCV RNA 24 weeks after treatment. The SVR rate was 48% in the combined T12PR12 and T12PR12 groups, compared to 46% in the PR48 group (P=0.89). The T12PR24 group had a higher SVR rate of 69% compared to the PR48 group (P=0.004). The T12PR12 group had a 60% SVR rate (P=0.12), and the T12PR12 group had a 36% SVR rate (P=0.20). Adverse events, including pruritus, rash, and anemia, were more frequent in the telaprevir-based groups. Telaprevir combined with peginterferon and ribavirin showed a significantly higher SVR rate than standard therapy (peginterferon and ribavirin alone). The SVR rate was highest in the T12PR24 group (69%), followed by the T12PR12 group (60%), and lowest in the T12PR12 group (36%). The addition of ribavirin improved SVR rates by preventing relapse and resistance. Ribavirin's mechanism of action remains unclear, but it is believed to enhance the antiviral effect of peginterferon. Telaprevir was associated with more frequent rash and pruritus compared to the control group. Severe rash occurred in approximately 5% of patients. These adverse events were generally mild to moderate and resolved after discontinuation of telaprevir. Hemoglobin levels decreased more in the telaprevir groups, but this was not a major cause of treatment discontinuation. In conclusion, telaprevir combined with peginterferon and ribavirTelaprevir, a specific inhibitor of the HCV serine protease, was evaluated in combination with peginterferon alfa-2a and ribavirin for chronic HCV genotype 1 infection. In a phase 2 trial, 334 patients were randomly assigned to four treatment groups: T12PR24 (telaprevir, peginterferon, ribavirin for 12 weeks, followed by peginterferon and ribavirin for 12 weeks), T12PR12 (telaprevir, peginterferon, ribavirin for 12 weeks), T12PR12 (telaprevir and peginterferon without ribavirin for 12 weeks), and PR48 (peginterferon and ribavirin for 48 weeks). The primary endpoint was a sustained virologic response (SVR), defined as undetectable HCV RNA 24 weeks after treatment. The SVR rate was 48% in the combined T12PR12 and T12PR12 groups, compared to 46% in the PR48 group (P=0.89). The T12PR24 group had a higher SVR rate of 69% compared to the PR48 group (P=0.004). The T12PR12 group had a 60% SVR rate (P=0.12), and the T12PR12 group had a 36% SVR rate (P=0.20). Adverse events, including pruritus, rash, and anemia, were more frequent in the telaprevir-based groups. Telaprevir combined with peginterferon and ribavirin showed a significantly higher SVR rate than standard therapy (peginterferon and ribavirin alone). The SVR rate was highest in the T12PR24 group (69%), followed by the T12PR12 group (60%), and lowest in the T12PR12 group (36%). The addition of ribavirin improved SVR rates by preventing relapse and resistance. Ribavirin's mechanism of action remains unclear, but it is believed to enhance the antiviral effect of peginterferon. Telaprevir was associated with more frequent rash and pruritus compared to the control group. Severe rash occurred in approximately 5% of patients. These adverse events were generally mild to moderate and resolved after discontinuation of telaprevir. Hemoglobin levels decreased more in the telaprevir groups, but this was not a major cause of treatment discontinuation. In conclusion, telaprevir combined with peginterferon and ribavir