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Abstract Details
Comparing direct acting antivirals for hepatitis C using observational data - Why and how?
Pharmacol Res Perspect. 2020 Oct;8(5):e00650. doi: 10.1002/prp2.650.
Jim Young123, Stanley Wong45, Naveed Z Janjua45, Marina B Klein126
Author information
1Division of Infectious Diseases and Chronic Viral Illness Service, Department of Medicine, Glen Site, McGill University Health Centre, Montreal, QC, Canada.
2Department of Epidemiology, Biostatistics and Occupational Health, Faculty of Medicine, McGill University, Montreal, QC, Canada.
3Basel Institute for Clinical Epidemiology and Biostatistics, University Hospital Basel, University of Basel, Basel, Switzerland.
4British Columbia Centre for Disease Control, Vancouver, BC, Canada.
5School of Population and Public Health, University of British Columbia, Vancouver, BC, Canada.
6CIHR Canadian HIV Trials Network, Vancouver, BC, Canada.
Abstract
The World Health Organisation's goal of hepatitis C virus (HCV) elimination by 2030 will require lower drug prices. Estimates of comparative efficacy promote competition between pharmaceutical companies but direct acting antivirals have been approved for the treatment of HCV without comparative trials. We emulated a randomized trial to answer the question of whether easy to treat patients with genotype 1 HCV could be treated with sofosbuvir/ledipasvir (SOF/LDV) rather than sofosbuvir/velpatasvir (SOF/VEL). Patients without comorbidities or end stage liver disease were selected from the British Colombia Hepatitis Testers Cohort. To create a conceptual trial, we matched each patient starting SOF/VEL (a 'case') to the patient starting SOF/LDV with the closest propensity score (a 'control'). We estimated the probability of treatment failure under a Bayesian logistic model with a random effect for each case-control set and used that model to give an estimate of a risk difference for the conceptual trial. Treatment failure was recorded for 27 of 825 (3%) cases and for 29 of 602 (5%) matched controls. Estimates from our model were treatment success rates of 97% (95% credible interval, CrI, 95%-98%) for treatment with SOF/VEL, 95% (95% CrI 93%-97%) for treatment with SOF/LDV and a risk difference between treatments of 2% (95% CrI 0%-4%). This risk difference is evidence that SOF/LDV is not inferior to SOF/VEL for easy to treat patients with genotype 1 HCV. The approach is a template for comparing drugs when there are no data from comparative trials.