A precision randomized trial to evaluate the impact of tailored hepatitis C treatment adherence support on HCV treatment outcomes among people who inject drugs in India: Design and Baseline Characteristics of the STOP-C Trial

Efforts to eliminate hepatitis C virus (HCV) as a public health problem must include people who inject drugs (PWID). We describe the design and baseline characteristics of the Supporting Treatment Outcomes among PWID (STOP-C) trial which evaluates whether HCV treatment outcomes in PWID can be optimized by tailoring treatment support in 7 PWID-focused integrated HIV/HCV prevention/treatment centers. The design is a 3-arm, individual-level precision-randomized trial. Leveraging empirical data, a prediction model assigned participants as minimal or elevated risk for failure. Minimal risk participants were randomized 1:2:3 to low- (basic services), medium- (patient navigation), and high-intensity (patient navigation + directly observed therapy) support, respectively. Elevated risk participants were randomized 3:2:1 to high, medium, and low-intensity support respectively. All received 12 weeks of oral direct-acting antiviral therapy. The primary outcome is sustained virologic response (SVR) 12 weeks after treatment completion in an intention-to-treat analysis. Three thousand participants were randomized (2048 [68%] minimal risk, 952 [32%] elevated risk of failure). This approach will allow for the estimation of efficacy within treatment failure risk strata while preserving the ability to estimate the average treatment effect and has particular relevance with increasing emphasis of precision medicine in health care delivery.