OBJECTIVE: CAB-LA administered every two months was recently approved in the US as PrEP for individuals at risk of acquiring HIV-1 infection based on the HPTN 083 and 084 studies, which both demonstrated superior reduction in HIV-1 acquisition compared with daily oral FTC/TDF in men who have sex with men (MSM), transgender women (TGW), and cisgender women. A decision-analytic model was developed to assess the lifetime cost-effectiveness of CAB-LA compared with FTC/TDF for HIV-1 PrEP in the US.
METHODS: The modeled population included individuals aged ≥18 years eligible to receive PrEP. Individuals entered the Markov model receiving either CAB-LA or FTC/TDF and could continue initial PrEP or choose alternate PrEP options or no PrEP over time. Efficacy was taken from the HPTN 083 and 084 clinical trials and adjusted for adherence and persistence. If HIV seroconversion occurred, individuals discontinued PrEP and were assumed to receive antiretroviral treatment and other associated HIV-related care for life. Secondary HIV-1 transmission to partners could also occur and, rarely, PrEP-related breakthrough resistance. Utility decrements and costs for PrEP and HIV-related care were obtained from published sources. The model estimated lifetime costs, quality-adjusted life-years (QALYs), and incremental cost-effectiveness ratios (ICERs) from a healthcare sector perspective with costs and health outcomes discounted at 3% annually. Sensitivity analysis was conducted to assess the impact of varying population subgroups, the comparator, high-risk duration, and PrEP adherence and persistence.
RESULTS: The model estimated that CAB-LA prevented more primary and secondary HIV-1 infections than FTC/TDF and yielded 0.21 fewer QALYs lost. Additional lifetime costs were $7,853, resulting in an incremental cost of $37,333 per QALY gained. For all scenarios analyzed, CAB-LA generally remained cost-effective or cost-saving with all ICERs at or below $107,693.
CONCLUSIONS: For populations at risk for HIV-1, CAB-LA for PrEP represents a cost-effective alternative to daily oral FTC/TDF.
