Dynamic choice HIV prevention with long-acting injectable cabotegravir pre-exposure prophylaxis in east, central, southern, and west Africa:a cost-effectiveness modelling analysis

BACKGROUND: In randomised controlled trials in Kenya and Uganda, a dynamic choice HIV prevention (DCP) intervention that offered structured choice of biomedical prevention product and opportunity to change products over time substantially improved prevention coverage; incident HIV infections were eliminated when long-acting cabotegravir was included as an option. We aimed to assess the potential cost-effectiveness of the intervention regimen in east, central, southern, and west Africa. METHODS: We used the existing individual-based HIV Synthesis model. Through sampling of parameter values at the start of each model run of a simulated population of adults, we created 1000 setting-scenarios, reflecting uncertainty in assumptions and a range of characteristics similar to those seen in east, central, southern, and west Africa. For each setting-scenario, we simulated predicted outcomes including disability-adjusted life-years (DALYs) and costs up to 50 years resulting from (1) continuing with the status quo (ie, no DCP); (2) introduction of the DCP intervention with oral pre-exposure prophylaxis (PrEP), post-exposure prophylaxis (PEP), and condoms without long-acting cabotegravir PrEP (ie, DCP without cabotegravir); and (3) introduction of the DCP intervention and including long-acting cabotegravir PrEP (ie, DCP including cabotegravir). We used a cost-effectiveness threshold of US$500 per DALY averted, and a discount rate of 3% per year. The annual cost of DCP including cabotegravir was assumed to be $190 per person. Net DALYs averted was calculated by DALYs averted plus the difference in costs divided by the cost-effectiveness threshold. FINDINGS: Reflecting the trial results, among people with a PrEP indication (ie, having an HIV acquisition risk) and an HIV test in the past 3 months, the median proportion of people on PrEP was 14% (90% range 4-43) with no DCP, 54% (23-74) with DCP without cabotegravir, and 71% (35-83) with DCP including cabotegravir. These increases in PrEP use led to HIV incidence reductions, with incidence rate ratios of 0·89 (0·67-1·17) for DCP without cabotegravir and 0·64 (0·44-0·97) for DCP including cabotegravir, relative to no DCP. Across setting-scenarios, both DCP policies led to DALYs being averted: 18 400 DALYs per year (95% CI 16 700-20 100) for DCP including cabotegravir and 56 400 DALYs per year (52 300-60 500) for DCP without cabotegravir in 10 million adults. Compared with no DCP, there was a mean increase in annual discounted costs over 50 years: $8·6 million (7·7-9·4) for DCP without cabotegravir and $13·2 million (11·6-14·8) for DCP including cabotegravir. Addition of long-acting cabotegravir PrEP to DCP was cost-effective (vs DCP without cabotegravir); the incremental cost-effectiveness ratio for DCP including cabotegravir (vs no DCP) was $234 per DALY averted. There was substantial variation across setting-scenarios and we found that DCP was more likely to be the cost-effective choice in settings with high prevalence of unsuppressed HIV or low proportion of people with an indication for PrEP. INTERPRETATION: Offering structured PrEP and PEP choice including long-acting cabotegravir and enabling risk-informed use could reduce HIV incidence by a third over 10 years. If projected generic production costs of long-acting cabotegravir can be realised, it is likely to be cost-effective across multiple settings in east, central, southern, and west Africa. FUNDING: US National Institutes of Health.