Australian experience shows high DAA uptake and rapid fall in rates of HCV viraemia among people who inject drugs

Providing hepatitis C virus (HCV) therapy with direct-acting antivirals (DAAs) to people who inject drugs can achieve rapid reductions in community prevalence of viraemia, according to Australian research published in the Journal of Hepatology. Uptake of HCV treatment increased from 10% to 41% after unrestricted access to DAAs was rolled out in March 2016, and the proportion of viraemic patients fell from 43% to 25%.

The authors believe their findings have significance for the World Health Organization (WHO) target of eliminating HCV as a public health threat by 2030.

“The elimination of HCV as a global public health threat will require strategies that provide DAA access to high-risk populations, often those who are highly marginalised in society,” comment the investigators. “This study provides evidence that relatively high rates of HCV treatment can be achieved among PWID [people who inject drugs] when DAA therapy is made available without restriction.”

All-oral HCV therapy using DAAs can achieve cure rates in excess of 95% with minimal toxicity. The availability of DAAs was instrumental in the development of the WHO target to eliminate HCV as a global public health threat by 2030. For elimination to be achieved, 80% of people with chronic HCV will need to receive DAA therapy, achieving a 65% reduction in HCV-related mortality and a 80% fall in HCV incidence.

Globally, people who inject drugs are one of the communities most affected by HCV. Stigmatised, criminalised and marginalised, people who inject drugs often face significant barriers accessing HCV therapy. But the achievement of the WHO elimination target will only be possible with widespread rollout of DAAs with corresponding reductions in the prevalence of viraemia in the most affected communities.

Starting in March 2016, unrestricted, subsidised access to DAA therapy was provided to all people with chronic HCV infection in Australia. Investigators analysed surveillance data collected from people who inject drugs between 2015 and 2017 to assess the impact of DAA rollout on treatment uptake and the proportion of people with HCV viraemia.

People were interviewed about their use of therapy and its outcome. Blood samples were also obtained to determine the prevalence of HCV antibodies and viraemia.

The annual study samples included ranged in size between 1995 and 2380 individuals. Approximately a third of participants were women, between 1.4% to 2.1% were HIV positive and 0.5% to 1% had HIV and HCV co-infection.

HCV antibody prevalence declined significantly from 57% in 2015 to 49% in 2017 (p < 0.001).

Spontaneous HCV cure was observed in between a fifth and a quarter of people with evidence of HCV infection.

Among people eligible for treatment (excluding individuals with spontaneous cure), treatment initiation rates increased from 10% in 2015, to 17% in 2016, and to 31% in 2017.

In the overall sample, prevalence of HCV viraemia declined from 43% in 2015, to 32% in 2016, and to 25% in 2017.

Trends in treatment initiation and viraemia were both highly significant (p < 0.001).

HCV re-infection or relapse was observed in 18 people. “The clearly demonstrated potential for PWID to be reinfected with HCV following successful DAA therapy is of concern,” comment the authors. “We believe the best approach to reinfection is enhanced harm reduction and rigorous monitoring for reinfection post-treatment with access to DAA therapy for retreatment.”

Older age (above 44 years vs below 37 years) was strongly associated with DAA treatment, as was history of opioid substitution therapy (aOR = 2.06; 95% CI, 1.30-3.26, p = 0.002).

“Australia is in an enviable position, with unrestricted subsidised access to DAA therapy among PWID and well established, high coverage harm reduction and prevention programs,” conclude the authors. “Findings from this study, including rapid uptake of DAA therapy and reduced viraemic prevalence of active HCV infection among PWID are encouraging and provide proof of concept that eliminating HCV as a public health threat through HCV treatment as prevention is feasible.”