Increasing national trend of direct-acting antiviral discontinuation among people treated for HCV 2016–2021

Direct-acting antiviral (DAA) treatment discontinuation may negatively impact HCV elimination efforts. In Australia, DAA therapy is pharmacy dispensed, generally in 4-week amounts, with the approved duration (8–24 wk) and volume dispensed reported in pharmaceutical administrative data. This analysis assessed national HCV treatment discontinuation. METHODS: Individuals commencing DAAs between 2016 and 2021 were assessed for treatment discontinuation. Individuals with a single dispensation of their entire treatment course were excluded. Treatment discontinuation was defined as ≥4 weeks of approved treatment duration not dispensed. Factors associated with treatment discontinuation were assessed using Cox regression. Factors associated with retreatment following treatment discontinuation were assessed using logistic regression. RESULTS: Of 95,275 individuals who were treated, 88,986 were included in the analysis of whom 7532 (9%) discontinued treatment. Treatment discontinuation increased from 6% in the first half of 2016 to 15% in 2021. Longer treatment durations (vs. 8 wk) were associated with increased discontinuation risk (12 wk: adjusted HR = 3.23; 95% CI: 2.90, 3.59; p < 0.001, 16–24 wk: adjusted HR = 6.29; 95% CI: 5.55, 7.14; p < 0.001). Of individuals discontinuing treatment, 24% were retreated. Early discontinuation (4 wk treatment dispensed) increased the likelihood of retreatment (adjusted OR = 3.91; 95% CI: 3.44, 4.44; p < 0.001). Those with early discontinuation of glecaprevir/pibrentasvir 8 weeks (vs. sofosbuvir/velpatasvir 12 wk) had a lower likelihood of retreatment (adjusted OR = 0.62; 95% CI: 0.49, 0.79; p < 0.001). Initial treatment discontinuation was associated with an increased risk of retreatment discontinuation (adjusted HR = 4.41; 3.85, 5.05; p < 0.001). CONCLUSIONS: DAA treatment discontinuation increased over time corresponding to increasing treatment uptake through primary care among people who inject drugs. The use of simplified, short-duration therapies may reduce treatment discontinuation. Access to adherence support and retreatment will be essential for HCV elimination.