Source University of Calgary Liver Unit, Calgary, Alberta, Canada. University Health Network, Toronto, Ontario, Canada. University of British Columbia, Vancouver, British Columbia, Canada. Toronto Digestive Disease Associates, Inc., Toronto. Toronto Liver Centre, Toronto. Gastroenterology and Hepatology Clinic, Abbotsford, British Columbia. Jewish General Hospital, McGill University, Montreal, Quebec, Canada. Syreon Corporation, Vancouver. Roche Canada, Mississauga, Ontario, Canada.

Background  The efficacy of individualised antiviral treatment durations for chronic hepatitis C remains unclear. Aim  To evaluate treatment durations based on virological responses at week 4, 8 and 12 of peginterferon alfa-2a plus ribavirin therapy.

Methods  Previously untreated patients with HCV genotypes, other than 2 or 3, initiated therapy with peginterferon alfa-2a 180 μg/week plus ribavirin 1000-1400 mg/day. HCV-RNA-negative patients at week 4 rapid virological response (RVR) were randomised to 24 or 48 weeks of treatment; those negative at week 8 were randomised to 36 or 48 weeks; and those who were negative or had a ≥2-log drop at week 12 were randomised to 72 or 48 weeks. Sustained virological response (SVR) was defined as undetectable HCV-RNA after 24 weeks of follow-up.

Results  The study was terminated prematurely due to lagging enrolment. Of 236 patients who started treatment, 195 were randomised at week 4 (n = 50), 8 (n = 61) or 12 (n = 84). Ninety-five per cent of patients had genotype 1. SVR rates were not significantly different between patients randomised to 24 (84%) or 48 weeks (84%) at week 4, to 36 (73%) or 48 weeks (74%) at week 8, or to 48 (49%) or 72 weeks (40%) at week 12.

Conclusions  In this predominantly genotype 1 cohort, shortening therapy to 24 weeks in patients with a week-4 response and 36 weeks in those with a week-8 response produced SVR rates that were similar to a 48-week regimen. Lengthening treatment to 72 weeks did not improve SVR rates. Genotype 1 patients with RVR can be treated for 24 weeks (clinicaltrials.gov NCT00483938).