Phase III C-EDGE CO-STAR study of Zepatier (elbasvir and grazoprevir) in hepatitis C published in Annals of Internal Medicine- Merck Inc

Merck Inc announced the publication of results from C-EDGE CO-STAR. C-EDGE CO-STAR is a Phase III trial evaluating the use of Zepatier (elbasvir and grazoprevir) 50mg/100mg tablets in patients with chronic hepatitis C (HCV) genotype (GT) 1, GT4 and GT6 infection receiving opioid agonist therapy (OAT) (methadone and buprenorphine), commonly used to treat opioid addiction. The results, published online in the Annals of Internal Medicine, showed treatment with 12 weeks of Zepatier resulted in high rates of sustained virologic response 12 weeks after the completion of therapy (SVR12, considered virologic cure based on undetectable HCV RNA levels). These results and full study design were previously presented at The Liver Meeting in November 2015.

The published efficacy results from the randomized, double-blind, placebo-controlled C-EDGE CO-STAR trial showed 92 percent (184/201) of patients receiving Zepatier for 12 weeks in the study�s immediate treatment group achieved SVR12, with comparable rates across GT1a (94%, 144/154), GT1b (93%, 28/30) and GT4 (92%, 11/12) patients; in the limited number of GT6 patients, SVR12 was 20 percent (1/5). These results classify patients who cleared their baseline infection but subsequently acquired a new infection as treatment failures; previously presented results from this trial considered these patients as treatment successes, according to the study protocol. A supportive analysis showed that the vast majority of patients were adherent to therapy, despite ongoing use of drugs of potential abuse (e.g., cocaine, heroin, amphetamines) by the majority of patients throughout the trial. The rates of adverse events were generally comparable between active treatment and placebo groups, with the most common adverse events (greater than 10%) in both groups including fatigue (16%, 20%), headache (12%, 13%) and nausea (11%, 9%), respectively. Secondary efficacy endpoint (SVR24) and reinfection analyses were presented at The International Liver Congress in April 2016.

See: "Elbasvir�Grazoprevir to Treat Hepatitis C Virus Infection in Persons Receiving Opioid Agonist Therapy: A Randomized Trial" Gregory J. Dore et al. Ann Intern Med. Published online 9 August 2016 doi:10.7326/M16-0816