Telaprevir Isn't Useful for All HCV Genotypes

Telaprevir-based triple therapy showed some promise against hepatitis C virus genotype 2 infection but had limited activity against genotype 3 infection.

Recently, telaprevir received FDA approval for use in triple therapy to treat hepatitis C virus (HCV) genotype 1 infection. The new triple regimens — peginterferon, ribavirin, and a protease inhibitor — are more efficacious than combination therapy (peginterferon and ribavirin) in patients with such infection. Although patients with HCV genotype 2 (G2) or genotype 3 (G3) infection generally respond well to combination therapy, 20% to 30% do not attain a sustained virologic response (SVR).

To evaluate the antiviral activity of telaprevir in treatment-naive adults with chronic HCV G2 or G3 infection, researchers conducted a phase IIa, manufacturer-sponsored, randomized, partially blinded study involving 23 G2-infected patients and 26 G3-infected patients.

Participants received one of three regimens for 2 weeks:

• Telaprevir 750 mg orally every 8 hours (monotherapy)
• Telaprevir plus peginterferon alfa-2a 180 µg once weekly plus ribavirin 400 mg twice daily (triple therapy)
• Placebo (every 8 hours) plus peginterferon and ribavirin

Thereafter, all participants received peginterferon and ribavirin for 22 or 24 weeks.

Among HCV G2-infected patients, SVR rates were 56% (5 of 9) with telaprevir monotherapy, 100% (5 of 5) with triple therapy, and 89% (8 of 9) with peginterferon plus ribavirin. However, among the HCV G3-infected patients, SVR rates were 50% (4 of 8), 67% (6 of 9), and 44% (4 of 9), respectively.

Comment: In this small exploratory study, telaprevir-based triple therapy showed some promise against HCV G2 but had limited activity against HCV G3. These findings highlight the fact that although protease inhibitor–based HCV treatment regimens are superior to peginterferon plus ribavirin for treating genotype 1 infection, the same might not be true for treating infections caused by other genotypes.

— Atif Zaman, MD, MPH

Published in Journal Watch Gastroenterology June 10, 2011

Citation(s):
Foster GR et al. Telaprevir alone or with peginterferon and ribavirin reduces HCV RNA in patients with chronic genotype 2 but not 3 infections. Gastroenterology 2011 Jun 1; [e-pub ahead of print]. (http://dx.doi.org/10.1053/j.gastro.2011.05.046)

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