The findings, which are based on prospective data from 13 countries, including the United States, and were published in Annals of Internal Medicine (2022 Aug 8. doi: 10.7326/M21-4119), should encourage physicians to treat HCV in people with a history of injection drug use, said lead author Jason Grebely, PhD. They should also pressure payers to lift reimbursement restrictions on the same population.
“Direct-acting antiviral medications for HCV infection are safe and effective among people receiving OAT and people with recent injecting-drug use,” the investigators wrote. “Concerns remain, however, that HCV reinfection may reduce the beneﬁts of cure among people who inject drugs and compromise HCV elimination efforts.”
They explored these concerns through a 3-year extension of the phase 3 CO-STAR trial that evaluated elbasvir and grazoprevir in people consistently taking OAT. Participants in the CO-STAR trial, which had a 96% sustained virologic response rate among those who completed therapy, could elect to participate in the present study, offering a prospective look at long-term reinfection.
Out of 296 participants in the CO-STAR trial, 286 were evaluable for reinfection and 199 enrolled in the present extension. The majority were White (79.4%) and male (75.9%), with most taking methadone (79%), followed by buprenorphine (20%). At 6 months, 40 out of 191 respondents (21%) reported injection-drug use in the previous month. At the 3-year mark, 26 out of 142 respondents (18%) disclosed injection-drug use in the previous month.
For all participants in the CO-STAR trial, the overall rate of reinfection at 3 years was 1.7 per 100 person-years (95% confidence interval, 0.8-3.0), which is lower than the rate reported in systematic reviews (3.8 per 100 person-years), according to the investigators.
In the extension analysis, the 3-year reinfection rate was lower still, at 1.2 per 100 person-years. The rate was slightly higher among people who reported injection-drug use in the previous month (1.9 per 100 person-years), and slightly lower among those who did not report injection-drug use in the prior month (0.5 per 100 person-years). More pronounced differences in reinfection were observed among participants who shared needles (6.4 per 100 person-years), versus those who didn’t share needles (1.5 per 100 person years).
Low reinfection rate may help facilitate removal of reimbursement restrictions
“Most of the reinfections in this study occurred within 24 weeks of completing treatment, suggesting that this is a key period for optimizing treatment of opioid use disorder and for providing access to needle and syringe programs that have documented beneﬁts in preventing HCV transmission,” the investigators wrote.
This is one of the largest observational studies of its kind to date, bolstered by “excellent study retention” and a “well-characterized cohort,” with findings that should prompt real-world action, said Dr. Grebely, who is head of the hepatitis C and drug use group in the viral hepatitis clinical research program at the Kirby Institute, University of New South Wales, Sydney.
“Given that reinfection has often been cited ... by some providers as a reason for not offering treatment to people receiving OAT, the low reinfection rate in this study will be incredibly important for guiding practice and ensuring therapy is not withheld from this group,” Dr. Grebely said in an interview. “In terms of policy implications, these data may also help to facilitate the removal of reimbursement restrictions based on recent drug/alcohol use criteria that are in place among many payers in the United States.”