Cost-effectiveness of cabotegravir versus tenofovir alafenamide plus emtricitabine versus tenofovir disoproxil fumarate plus emtricitabine for pre-exposure prophylaxis to prevent HIV-1 transmission in gay, bisexual and other men that have sex with men.

Background: This study aims to compare the cost-effectiveness of currently approved daily PrEP in Spain, with tenofovir disoproxil fumarate plus emtricitabine (TDF/FTC), in gay, bisexual and other men who have sex with men (GBMSM) versus newer alternatives like daily tenofovir alafenamide plus emtricitabine (TAF/FTC) or injectable cabotegravir every 2 months (CAB).

Methods: We fitted a dynamic compartmentalized Markov model that represents the dynamics of HIV-1 transmission in GBMSM in Spain. The model was calibrated to replicate the epidemiological data of the HIV epidemic in GBMSM in Spain from 2013 to 2018. We used the perspective of the national health system and applied a 40-year time horizon. Quality-adjusted life years (QALYs) were the health outcome variable, and the cost was accounted for in 2018 Euros (€). Our outcome variable was the incremental cost-effectiveness ratio (ICER) for PrEP. We used the 2018 gross domestic product per capita of Spain (€25,854) as the willingness-to-pay (WTP) threshold.

Results: The 2019 scenario with no PrEP in place would yield 17,424,891 QALYs and a cost of 2018 €17,345,310,254. The present scenario of daily TDF/FTC yields 18,615,325 QALYs, an increase of 1,190,434 QALYs at a cost of 2018 €15,354,878,534 (decrease of -2018 €1,990,431,719), generating an ICER of -2018 €1672 per QALY gained. The introduction of daily TAF/FTC in the present scenario would yield an increase in 449,392 QALYs at an additional cost of 2018 €13,634,260,217. The ICER would thus be 2018 €30,339 per QALY gained. Introducing CAB in the present scenario would yield an increase of 573,007 QALYs at an additional cost of 2018 €16,754,471,790 (average cost-effectiveness ratio=29,239). Compared to TAF, the increase in QALYs would be 123,614 at an additional cost of 2018 €5,707,367,590, yielding an ICER of 2018 €46,170/QALY gained. A one-way sensitivity analysis and a probabilistic sensitivity analysis was carried out.

Conclusions: The present Spanish policy of PrEP is a cost-saving strategy. TAF/FTC and CAB are not cost-effective at current market prices.