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Patients infected with hepatitis C virus fare best with optimal dosage and adherence to combination medications

Research Activities, June 2009, No. 346

Patients suffering from hepatitis C virus (HCV) infection must endure a grueling drug regimen that includes weekly subcutaneous injections of pegylated interferon (IFN), twice-daily pills of ribavirin, and frequent monitoring of adverse effects and laboratory results. Consistently taking 85 percent or more doses of the combined medication is linked to increased HCV suppression and early viral response (EVR), according to a new study. Decline in HCV load became even greater when patients had 85 percent or more adherence to their regimen and were prescribed the recommended weight-based ribavirin dosage throughout the initial 12 weeks of treatment.

Clinicians should consider poor treatment adherence as a possible cause of virologic nonresponse during HCV therapy, recommend researchers at the Center for Education and Research on Therapeutics (CERT) at the University of Pennsylvania. They used pharmacy refill data to examine adherence of 188 patients with chronic HCV infection to pegylated IFN and ribavirin therapy and its impact on HCV load and early virologic response at 12 weeks.

The mean decrease in HCV load at 12 weeks was 0.66 log IU/mL greater for patients with 85 percent or higher adherence than for those with less than 85 percent adherence. When patients who received a suboptimal ribavirin dosage were excluded, the decrease in viral load was even better -1.00 log IU/mL more for persons with 85 percent or greater adherence compared with those with less adherence to pegylated INF (73 vs. 29 percent) and ribavirin (73 vs. 55 percent).

The study was supported in part by a grant from the Agency for Healthcare Research and Quality (HS10399) to the University of Pennsylvania CERT. For more information on the CERTs program, visit

See "Adherence to hepatitis C virus therapy and early virologic outcomes," by Vincent Lo Re III, M.D., M.S.C.E., Valerianna K. Amorosa, M.D., A. Russell Localio, J.D., M.P.H., Ph.D., and others, in the January 15, 2009, Clinical Infectious Diseases 48, pp. 186-193.

Current as of June 2009
Internet Citation: Patients infected with hepatitis C virus fare best with optimal dosage and adherence to combination medications: Research Activities, June 2009, No. 346. June 2009. Agency for Healthcare Research and Quality, Rockville, MD.