C-EDGE CO-STAR: Adherence and Drug use in HCV-Infected Persons who Inject Drugs (PWID) on Opioid Agonist Therapy (OAT) receiving Grazoprevir + Elbasvir (GZR/EBR) fixed Dose Combination (FDC) for 12 Weeks

Author: Dore G, Grebely J, Altice F, Litwin A, Dalgard O, Gane E, Shibolet O, Luetkemeyer A, Nahass R, Peng C, Conway B, Nguyen B, Wahl J, Barr E, Robertson M, Platt H

Theme: Clinical Research Year: 2015

Introduction: The majority of new cases of HCV occur among people who inject drugs (PWID). However, HCV treatment uptake among PWID has been constrained by concerns regarding adherence and reinfection. The combination of GZR/EBR (GZR, NS3/4A protease inhibitor, 100mg)/(EBR; NS5A inhibitor, 50mg), a single tablet once-daily, interferon- and ribavirin-free FDC, has demonstrated robust efficacy and safety profiles in diverse populations.

Methods: C-EDGE CO-STAR is a phase-III study that enrolled patients with chronic HCV genotype 1, 4 or 6 on OAT (either methadone or buprenorphine). This on-going, double-blind, placebo-controlled study randomized patients 2:1 to the immediate (ITG) or deferred treatment group (DTG). The ITG received GZR/EBR for 12 weeks; DTG received placebo for 12 weeks, then 4 weeks of unblinding, then 12 weeks of GZR/EBR. On-treatment adherence was assessed via an electronic study medication diary. OAT and non-prescribed drug use was assessed through urine drug screen (UDS) at each visit. Efficacy and safety results will be presented elsewhere.

Results: Of 301 randomized patients (mean age 47 years; male, 76%; black, 13%; GT1a, 76%; cirrhotic, 20%; HIV positive, 7%), 98% (n=295) completed the blinded treatment phase and >90% of patients adhered to >95% of study medications (GZR/EBR or placebo). There was no change in the proportion receiving methadone (77% vs. 75%) or buprenorphine (21% vs. 21%) between baseline and end of treatment. There was also no change in other opioid (21% vs. 22%), benzodiazEpidemiology & Public Health Researchne (25% vs. 26%), cocaine (10% vs. 12%), amphetamine (5% vs. 4%), and cannabinoid use (29% vs. 34%).

Conclusion: This phase III study of HCV-infected PWID receiving OAT demonstrates a high proportion completing therapy, high study medication adherence, and stable ongoing drug use without any appreciable increase in frequency of any specific drug category throughout the trial. This on-treatment data demonstrate support for treating HCV among PWID receiving OAT.

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