National Direct Acting Antiviral Treatment and Retreatment Discontinuation in Australia

Author: Joanne Carson Sebastiano Barbieri Gregory Dore Gail Matthews Behzad Hajarizadeh

Theme: Clinical Research Year: 2022


Direct acting antiviral (DAA) discontinuation may negatively impact hepatitis C virus (HCV)
elimination efforts, particularly among marginalized populations not engaged in regular HCV care. In
Australia, DAA dispensations are reported through the Pharmaceutical Benefit Scheme, including
authorized treatment duration and volume dispensed. This analysis aimed to assess DAA treatment
discontinuation in Australia.


Individuals dispensed DAAs between 2016-2021 were included. Treatment discontinuation was
defined as ≥28 doses of authorized duration not dispensed. To avoid misclassification bias due to
clinician-directed shortening of longer duration courses, individuals prescribed the minimum DAA
duration (8-12 weeks) for each regimen were included in analyses. Factors associated with
discontinuation were assessed using Cox regression.


Among 95,274 people treated for HCV, 59% (n=56,095) received the minimum DAA duration (male
69%; median age 49) of whom 8% (n=4678) discontinued treatment, increasing over time (Figure).
Younger age (adjusted hazard ratio [AHR] 1.25/10-year decrease; 95%CI 1.22-1.28), receiving lowincome subsidy prescriptions (AHR 1.66; 95%CI 1.545-1.77), treatment by general practitioner (vs.
gastroenterologist; AHR 1.39; 95%CI 1.27-1.49), HIV treatment (AHR 1.35; 95%CI 1.07-1.70) and later
year of treatment commencement (AHR 1.16/year; 95%CI 1.12-1.19) significantly increased
discontinuation risk. Compared to sofosbuvir/velpatasvir 12-weeks, glecaprevir/pibrentasvir (AHR
0.75; 95%CI 0.68-0.53) or sofosbuvir/lepidasvir (AHR 0.69; 95%CI 0.60-0.80) 8-week durations had
lower discontinuation risk. Among 6,808 people retreated for HCV, 58% (n=3,917), received the
minimum DAA duration (male 80%, median age 41) of whom 13% (n=512) discontinued treatment.
Discontinuing initial treatment (AHR 2.25; 95%CI 1.87-2.72) significantly increased retreatment
discontinuation risk. Among people discontinuing initial treatment, 26% (n=1203/4678) received
retreatment. Among people discontinuing retreatment, 28% (n=137/512) received second


DAA discontinuation risk increased over time, corresponding to increasing treatment uptake among
younger people who inject drugs through primary care. Treating with short-duration DAAs, alongside
targeted interventions to enhance adherence may improve treatment outcomes and reduce

Disclosure of Interest Statement:

The Kirby Institute is funded by the Australian Government
Department of Health and Ageing. The views expressed in this publication do not necessarily
represent the position of the Australian Government.

Download abstract