Anti-HCV treatment effective in drug abusers receiving opioid agonists

Last Updated: 2016-08-08

By Will Boggs MD

NEW YORK (Reuters Health) - Anti-hepatitis C virus (HCV) treatment is feasible and effective in patients receiving opioid agonist therapy, according to results from the CO-STAR trial.

"The study clearly demonstrates that patients with chronic hepatitis C who are on opiate agonist therapy (methadone, buprenorphine), including those with ongoing illicit drug use, have treatment outcomes equivalent to other patient populations," Dr. Gregory J. Dore from The Kirby Institute, University of New South Wales, Australia told Reuters Health by email.

Phase 1 studies had found no significant drug interactions between methadone or buprenorphine and elbasvir-grazoprevir, a fixed-dose direct-acting antiviral (DAA) combination recently approved in the U.S. for treating HCV genotypes 1 and 4.

Dr. Dore and colleagues in the CO-STAR trial evaluated the efficacy and safety of a 12-week regimen of elbasvir-grazoprevir for HCV-infected persons who inject drugs who were receiving opioid agonists.

Of the 301 patients, 201 were randomly assigned to the immediate treatment group and 100 were randomly assigned to the delayed treatment group, which received placebo for the first 12 weeks of the study, then nothing for four weeks, and then elbasvir-grazoprevir for 12 weeks.

The sustained virologic response at 12 weeks (SVR12), the primary outcome, was 91.5% in the immediate treatment group and 89.5% in the active phase of the delayed treatment group, the authors reported online August 8 in Annals of Internal Medicine.

Of the 17 patients in the immediate treatment group who did not achieve SVR12, seven had findings consistent with relapse, five had signs consistent with probable reinfection, and five had non-virologic reasons for failure.

Of the 10 patients in the delayed treatment group who did not achieve SVR12, three had viral recurrence and seven were lost to follow-up.

Results were similar for patients with cirrhosis and for the more than 50% of patients who tested positive on urine drug screens for drugs of abuse other than methadone and buprenorphine.

Adherence greater than 95% was reported by 96.5% of patients in the immediate treatment group and by 95.8% of patients in the active phase of the delayed treatment group.

"The high level of treatment adherence was extremely encouraging, with no impact of ongoing illicit drug use on either adherence or treatment outcome," Dr. Dore said.

The safety profile of elbasvir-grazoprevir in the immediate treatment group was similar to that of placebo in the delayed treatment group.

"Many patients with chronic hepatitis C who have ongoing illicit drug use and are highly motivated to achieve a cure are able to adhere to DAA therapy and have favorable treatment outcomes," Dr. Dore concluded.

"The study did not enroll patients who were injecting drugs not on opiate agonist therapy," Dr. Dore added. "Ongoing studies are evaluating direct-acting antiviral (DAA) therapy in this population."

"Despite the need for further evidence, there are no reasons to deny potential DAA therapy for patients who are injecting," he said. "Treatment suitability should be assessed on an individual basis for all patients with chronic hepatitis C."

Merck & Co., Inc. funded the study, employed 10 of the 22 authors, and had various relationships with 11 of the other authors.

SOURCE: http://bit.ly/2b9ByKz

Ann Intern Med 2016.