Population-level impact of expanding PrEP coverage among men who have sex with men with long-acting injectable cabotegravir: model comparison analysis for Atlanta, US and Montreal, Canada


BACKGROUND: Long-acting injectable cabotegravir (CAB-LA) demonstrated superiority to daily oral tenofovir disoproxil fumarate/emtricitabine (TDF/FTC) for HIV pre-exposure prophylaxis (PrEP) in the HPTN 083/084 trials and is currently approved for HIV prevention in the United States. We compared the potential impact of expanding PrEP coverage by offering CAB-LA to men who have sex with men (MSM) in Atlanta, US/Montreal, Canada, cities with different HIV epidemics.
METHODS: Two age- and risk-stratified HIV transmission models were independently parameterised and calibrated to local data. Scenarios achieving 40% and 50% PrEP coverage after 5 and 10 years by switching 0%-50% of TDF/FTC users to CAB-LA in 2022 and recruiting additional CAB-LA users were simulated. Intervention impact was measured as the proportion of cumulative HIV infections averted over 20 years compared to base-case scenarios with TDF/FTC use only (median values presented).
RESULTS: Model simulations predict that, in the base-case without CAB-LA, overall PrEP coverage in Atlanta/Montreal could reach 32%/10% by 2042 with HIV prevalence decreasing to 17%/2%. Achieving 40% PrEP coverage in 2027 by adding CAB-LA is expected to avert 37%-40% of new HIV infections over 20 years in Atlanta and 47% in Montreal (Figure). Switching TDF/FTC users to CAB-LA (0% vs 50%) has a modest impact (~3 percentage points increase (pp)) in Atlanta with no clear effect in Montreal where base-case PrEP coverage is significantly lower. Delaying achieving 40% coverage until 2032 reduces the impact by 4pp and 9pp in Atlanta and Montreal, respectively. Reaching 50% PrEP coverage in 2027 increases the impact in Atlanta by 16pp-18pp and by 8pp-10pp in Montreal compared to 40% coverage.

CONCLUSIONS: Achieving high PrEP coverage by offering CAB-LA could impact the HIV epidemics substantially if rolled out without delays. Recruiting additional new CAB-LA users is expected to have a greater impact on preventing new HIV infections than switching current TDF/FTC users to CAB-LA.

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