HCV Patients Who Inject Drugs Show Treatment Adherence Similar to Non-Users, Study Finds

The Ireland-based study observed the results of a 10-year treatment program.

Hepatitis C patients who inject drugs showed no significant difference in sustained virologic response rates or adherence to therapy regimens when compared to non-drug users, according to a review of a 10-year treatment program in Ireland.

The results challenge perceptions among some providers that people who inject drugs (PWID) are difficult to treat and their therapy should be delayed or denied. The study was led by Dr. Omar El-Sherif and his colleagues at St. James’s Hospital in Dublin.

“The use of pre-treatment screening tools for illicit drug use do not help in identifying patients more likely to respond to therapy, and only serve as an added barrier to treatment,” the authors wrote.

PWID represent the majority of the HCV epidemic in the developed world, with most new infections arising in active injecting drug users, according to the study.

However, historically, HCV treatment guidelines have excluded PWID from consideration for treatment “because of concerns regarding compliance and re-infection,” the authors wrote.

To assess compliance and response rates to hepatitis C therapy, the authors studied data for 1,000 patients who had compensated chronic HCV infection and detectable HCV RNA. The individuals underwent treatment with peginterferon-α subcutaneous injections and weight-based ribavirin (Peg-IFNα/RBV) in a university teaching hospital from 2002—2012. The therapy lasted for 24 or 48 weeks based on genotype and the presence of pre-existing cirrhosis.

Among those selected for the study, 608 had had no injecting drug use for 6 months before therapy; 85 had injected drugs within 6 months, and 307 were non-drug users. The groups were compared for baseline characteristics, treatment adherence, and outcome.

Of the recent or former PWID who began treatment, more than 90% completed the course, the study found. The overall SVR rate in PWID was 64.1%, similar to the non-PWID rate of 60.9%.

There was no significant difference in SVR rates between the groups when comparing genotype 1 and genotype 3 infections. As expected genotype 1 infection was less responsive to interferon therapy in both PWID and non-PWIDs, the authors noted.

“This large retrospective study of a decade of HCV treatment outcomes demonstrates that PWID have similar treatment adherence to peginterferon and ribavirin as non-PWID patients with chronic HCV infection,” the researchers wrote.

Researchers added that the data supported the inclusion of recent and former PWID “in any public health HCV treatment strategy aimed at reducing HCV prevalence as a first step towards elimination.”

The recent advent of direct-acting antiviral (DAA) drugs provides a stronger case for inclusion, the authors suggest. These medicines limit treatment duration to as short as 8 weeks and achieve SVR rates of more than 95%. At the same time, the pills do not produce the debilitating side effects common among interferon-based therapies.

“As treatment regimens become simpler and more tolerable, this should result in an expansion of the eligible treatment population,” the authors wrote. “HCV elimination is an ambitious target, but it will not be achieved by excluding PWID from treatment.”

The study, "Outcomes from a large 10 year hepatitis C treatment programme in people who inject drugs: No effect of recent or former injecting drug use on treatment adherence or therapeutic response," was published online in the journal PLOS.

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