1018 - Health Technology Assessment of New Long-Acting, Directly-Observed HIV Treatments in Canada: Impact of Real-World Adherence to Daily Oral Therapy on Treatment, Transmission and Cost-Effectiveness

Background: Current antiretroviral therapy (ART) has dramatically improved outcomes for people living with HIV (PLWHIV), however adherence to daily oral dosing remains a challenge for some. New, long-acting (LA) ARTs which are directly administered by physicians eliminate the need to adhere to daily oral dosing and may improve clinical outcomes. The study objective was to evaluate costs and QALYs associated with improved adherence achieved via a novel, directly-observed therapy (DOT) of a monthly LA injectable ART, compared to standard of care (SoC), daily oral therapy.

Methods: A published Markov cohort state-transition model was adapted to model the impact of treatment adherence and subsequent disease transmission. Without the need to adhere to daily dosing, the efficacy of the injectable was modelled independent of adherence whereas virologic suppression in the SoC arm was adjusted to reflect published data on adherence to daily dosing (8.12% below optimal levels observed in clinical trials).

Results: This evidence-based approach of accounting for adherence revealed an increase in lifetime costs for oral SOC of approximately $850, and QALY loss of 0.109 when compared to results without accounting for adherence. Disease transmission results yielded 3 cases averted of HIV per 1,000 patients with LA’s impact on adherence.

Conclusion: In the absence of comparative adherence estimates between a LA, injectable DOT and daily oral therapy in the real world, an evidence-based approach provides a method to address the uncertainty around the true impact on costs and QALYs of a novel mode of administration.