Hepatitis C virus (HCV) reinfection was uncommon among patients on opioid substitution therapy after successful treatment with a direct-acting antiviral (DAA) medication, even when illicit drug use continued, a 3-year follow-up shows.

The findings suggest that broadened access to new DAA treatments for people who inject drugs (PWID) may help tame HCV infections among this population, according to author Jason Grebely, an associate professor at the Kirby Institute at the University of New South Wales in Sydney, Australia.

Grebely said HCV is affecting 2 main populations that have drug-injecting histories. People who were infected with the liver-attacking virus in the 1970s and 1980s are becoming more vulnerable as they age. At the same time, HCV is spreading, particularly in the United States, as new individuals inject heroin and other drugs amid the escalating opioid epidemic.

“We really need to be considering this population,” Grebely said of illicit drug users. “The burden is growing.”

Grebely and colleagues studied patients who enrolled in the C-EDGE Co-STAR study, the first randomized controlled trial that specifically looked at injection drug users who receive opioid substitution therapy (OST).

The patients were given a 12-week course of DAA treatment with grazoprevir/elbasvir (Zepatier/Merck & Co.). Some 91% of the participants achieved sustained virologic response, or undetectable HCV RNA, at 12 weeks after completing therapy.

In the follow-up, 185 of the original 296 Co-Star participants on OST were tracked for 3 years. Their HCV viral load was assessed every 6 months. If positive, the patient underwent viral sequencing to compare the original virus to the recurrent virus.

Drug use stayed about the same in both of the study phases. In the follow-up, 58% reported some type of drug involvement in the previous 6 months. Injecting drug use was reported by 25%, with 72% of those individuals using heroin.

The study considered the participants’ habits. Among those who reported injecting any drugs within the previous month, 81% said they used sterile syringes all the time and 17% did so most of the time. One person said he never used a clean needle. No one reported using a needle after someone else had used it. However, 42% said they had used other injection-related equipment or supplies after someone else.

The rate of reinfection after successful treatment with elbasvir/grazoprevir therapy for participants on opioid therapy was 4 per 100 person-years, according to the report. This included recent injecting-drug users.

However, the authors cautioned that positive HCV antibodies gained in successful treatment do not provide protection against re-exposure. “HCV reinfection can occur in people with ongoing risk behaviors,” they said.

The researchers stressed the importance of rapidly scaling up DAA therapy among drug injectors. Slow progress in introducing HCV intervention among this population will lead to people who are “susceptible” to reinfection without substantially reducing the viremic population, they said.

The authors also supported the expansion of opioid substitution therapy and high-coverage needle exchange programs to prevent HCV reinfection. They said restrictions to patients’ receiving DAA therapy based on liver disease stage, drug or alcohol use, or insurance coverage must be removed to enable broad access.

The study, “Treatment of HCV in Persons Who Inject Drugs: Treatment as Prevention,” was published in April 2017 in Clinical Liver Disease. Grebely presented the fin

Related Coverage:

Study Suggests New Way to Fight Hepatitis C, Other Infections

Regular Screening Is Key for Hepatitis C

FDA Approves Two Drugs for Opioid Dependence