Source
Department of Medicine, Division of Gastroenterology bThe Ottawa Hospital Division of Infectious Diseases Viral Hepatitis Program cThe Ottawa Hospital Research Institute, University of Ottawa, Ottawa, Canada.
Abstract
BACKGROUND:
Trial effect refers to the impact of clinical trial participation on treatment outcomes. Little literature exists evaluating the magnitude and direction of trial effect in hepatitis C virus (HCV).
METHODS:
A single-center, retrospective study on HCV antiviral therapy recipients was conducted. Sustained virologic response (SVR), virologic response at treatment weeks 4 and 12, dose interruptions, and adverse events were compared between clinical trial participants and standard-of-care antiviral recipients between September 2000 and November 2011.
RESULTS:
A total of 449 patients were evaluated (trial: 89, nontrial: 360). Patients were matched for age (trial: 47 years, nontrial: 45 years), sex (male: trial, 74%; nontrial, 72%), and ethnicity (white: trial, 87%; nontrial, 78%). The groups differed in the incidence of genotype 1 infection (trial: 83%, nontrial 53%; P<0.001), liver biopsy rates (trial: 98%, nontrial: 66%; P<0.001), and history of psychiatric illness (trial: 30%, nontrial: 53%; P<0.001). On intent-to-treat analysis, SVR rates were found to be similar (trial: 51%, nontrial: 54%; P=0.86), even when stratified for genotype (G1: trial, 47%; nontrial, 47%; P=0.78). Interferon dose reductions (trial: 18%, nontrial: 6%; P<0.01) were more likely in trial patients, whereas treatment discontinuation because of side effects (trial: 8%, nontrial: 18%; P<0.02) was less likely in them. No differences in safety issues were identified.
CONCLUSION:
Overall, a trial effect resulting in improved or diminished SVR rates was not identified.