Reinfection rates are low after treating hepatitis C virus in people taking opioid agonist therapy (OAT), even among those who still inject drugs, according to a new study.
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 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," 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."
More Research Needed to Determine Optimal Intervention Strategies
Carl Latkin, PhD, professor and vice chair of the department of health, behavior, and society at Johns Hopkins University, Baltimore, called the present publication a "great article and well-done study with long-term follow-up."
Latkin, who investigates biobehavioral interventions for disadvantaged communities, said the reported rate of reinfection is "very low among a group of current and former injectors."
Affirming Grebely's call for supportive practices by physicians and payers, Latkin said: "The study highlights the importance of improving access to medication for opioid use disorder. This level of treatment adherence in this group is much higher than for many other medications. Given these data, it would be difficult for payers to have a rational reason for blanket restrictions for HCV treatment among people who use drugs."
Latkin explained that "it isn't simply injection drug use per se" that drives HCV reinfection; instead, he cited social factors, such as lack of housing, as well as withdrawal symptoms, especially among those without access to medications for opioid use disorder (MOUD).
Latkin and Grebely also agreed that more research is needed to determine optimal intervention strategies.
Grebely called for one to enhance HCV testing and linkage to care, a topic he covered in a recent review article (Lancet Gastroenterol Hepatol. 2022 May;7:426-45.).
Latkin said that, while it's clear that "syringe services programs, accessible HCV treatment, and MOUD are needed," it is unclear how much coverage is necessary for a given population.
Findings Support Critical Nature of Needle and Syringe Exchange Programs
Sarah M. Kattakuzhy, MD, an associate professor in the division of clinical care & research at the Institute of Human Virology, University of Maryland, Baltimore, agreed that the findings "support the critical nature of needle and syringe exchange programs."
"As most cities in the United States fall well below the high coverage needle and syringe program threshold required to maximally prevent disease transmission, the study serves as a push toward an evidence-based harm reduction policy," she said.
Kattakuzhy he added that the study "supports the need to longitudinally engage individuals after HCV treatment to monitor reinfection risk behaviors and test for reinfection," she continued.
When it came to translating all the data to populations in the United States, she offered a more guarded view.
"Critically, the study population included only individuals who were engaged with OAT and adherent for 3 or more months, selecting to a population of individuals with high adherence and engagement in care," Kattakuzhy said in an interview. "As such, the study findings are not applicable to other cross sections of the drug-using community, including individuals not engaged in OAT, and cohorts with higher rates of ongoing injection drug use. Furthermore, there are known genetic impacts on spontaneous clearance, and emerging data on the immunology of reinfection.
"Studies with a focus on less engaged, higher-risk, and minority populations with active drug use are required to answer the remaining questions in HCV reinfection," she said.
The study was supported by Merck, the Australian Government Department of Health, and the Australian National Health and Medical Research Council. Grebely disclosed receiving funding from Cepheid, the manufacturer of the Xpert HCV assay. The other investigators disclosed additional relationships with Gilead, AbbVie, Cepheid, and others. Latkin and Kattakuzhy disclosed no relevant conflicts of interest.
This article originally appeared on MDedge.com, part of the Medscape Professional Network.
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Cite this: HCV Reinfection Uncommon Among People Who Inject Drugs - Medscape - Aug 09, 2022.