New, highly curative hepatitis C therapy is both safe and effective as a treatment option for people who inject drugs,  the major population affected by the virus, according to a paper in the Annals of Internal Medicine.

Yet clinical trials for direct acting antiviral hepatitis C treatment have to date excluded people who were actively injecting drugs based on concerns around adherence to medication and risk of reinfection. People who are receiving regular opioid substitution therapy have also been excluded from clinical trials if they demonstrate ongoing illicit drug use, says Professor Gregory Dore at the Kirby Institute at UNSW Australia, who led a new trial where participants were drawn from a population currently on opioid substitution therapy, which included a majority of participants who had ongoing illicit drug use. The clinical trial is called C-EDGE CO-STAR and was funded and conducted by MSD, the tradename of Merck&Co. Dore was the lead investigator. Patients for the trial were recruited from a large international network of sites that included St Vincent's Hospital, Sydney. 

"The results of this trial show that illicit drug use prior to and during hepatitis C therapy had no impact on the effectiveness of the therapy, and that reinfection was low, at 4 per cent," said lead investigator, Professor Gregory Dore who is also a physician at St Vincent's Hospital in Sydney. "The results also show excellent treatment adherence. At greater than 95 per cent, this is comparable to results in hepatitis C populations that exclude people who use drugs."

In some countries, including the United States, people who have not ceased injecting drug use or people who are receiving opioid substitution therapy are ineligible or not considered suitable by general practitioners to receive new treatments.

Professor Dore believes that the results of this trial provide important data to support the removal of drug use as a restriction to access interferon-free hepatitis C treatment.

"In Australia, thanks to advocacy, research and government support we are realistically talking about ending hepatitis C by 2026," said Professor Dore. "The availability and accessibility of treatment has been vital to Australia being in this exciting position. I am optimistic that the results from this study will help to reduce stigma associated with drug use and hepatitis C infection and really open up access to hepatitis C treatment globally."