OBJECTIVE: The HPTN-083 and -084 studies demonstrated superior risk reduction in HIV-1 acquisition with CAB-LA for PrEP compared with daily oral TDF/FTC. The introduction of a new injectable PrEP modality may encourage uptake of PrEP by individuals who are not taking TDF/FTC or are sub-optimally adherent to TDF/FTC. A published Markov model was adapted to assess the cost-effectiveness of CAB-LA compared with TDF/FTC or not receiving PrEP (No PrEP) for HIV-1 prevention in the UK.
METHODS: Background HIV-1 incidence without PrEP use was informed by local epidemiology data. The effectiveness of CAB-LA and TDF/FTC were taken from an indirect treatment comparison based on the HPTN-083 and -084 trials, which included a meta-regression to allow for exploration of TDF/FTC effectiveness at different levels of adherence (a treatment-effect modifier). If HIV seroconversion occurred, individuals discontinued PrEP and received lifetime HIV-related care. Secondary HIV-transmissions and PrEP-related breakthrough resistance could occur. Utility decrements and costs were obtained from published sources. The model estimated lifetime costs, quality-adjusted life-years (QALYs), and incremental cost-effectiveness ratios (ICERs) from the NHS perspective with costs and health outcomes discounted at 3.5% annually. Sensitivity analyses were conducted to assess the impact of key parameters including duration of HIV–acquisition risk, TDF/FTC adherence, and PrEP persistence.
RESULTS: The model estimated that CAB-LA prevented more primary and subsequently secondary HIV infections versus both TDF/FTC and No PrEP, and yielded 0.21 and 0.50 more QALYs gained, respectively. Lifetime costs were £4,311 and -£13,657, respectively, resulting in ICERs of £20,476 and -£27,171 (dominant). CAB-LA generally remained cost-effective or cost-saving across sensitivity analyses.
CONCLUSIONS: For the modelled populations at-risk for HIV, CAB-LA for PrEP represents a cost-effective alternative to daily oral TDF/FTC. Furthermore, CAB-LA would be a cost-effective option for individuals who may have not considered PrEP use to date because they are unable or unwilling to take TDF/FTC.
