Highly curative hep C treatment safe, effective for drug users

Up to 170 million people worldwide have hepatitis C virus (HCV) infection and injection drug use is a major risk factor. While the once-daily dosing, low side-effects profile, and shortened treatment duration of interferon-free direct-acting antivirals are ideal for injection drug users, most trials of these therapies for HCV have excluded persons with recent injection drug use.

The CO-STAR (Hepatitis C Patients on Opioid Substitution Therapy Antiviral Response) trial sought to evaluate the efficacy and safety of elbasvir-grazoprevir for injection drug users. Researchers assigned 301 treatment-naive patients with chronic HCV genotype 1, 4, or 6 infection who were at least 80 percent adherent to visits for opioid-agonist therapy to immediate treatment with elbasvir-grazoprevir for 12 weeks, or deferred treatment with placebo for 12 weeks, then open-label elbasvir-grazoprevir for 12 weeks. They found that 91.5 percent of the patients in the immediate treatment group achieved sustained virologic response, regardless of ongoing drug use. According to the authors, these results suggest that drug use should be removed as a barrier to interferon-free HCV therapy for patients being treated for opioid addiction.