Cost-effectiveness of leveraging long-acting injectable cabotegravir to expand PrEP coverage among MSM in two contrasting North American cities.

introductionLong-acting injectable cabotegravir (CAB-LA) is superior to daily oral tenofovir disoproxil fumarate/emtricitabine (TDF/FTC) for HIV pre-exposure prophylaxis (PrEP) and could expand PrEP usage. Given price differentials between CAB-LA and TDF/FTC, evaluating the cost-effectiveness of potential PrEP coverage scenarios is warranted.

methodsWe simulated PrEP coverage expansion among men who have sex with men (MSM) via introducing CAB-LA using two age- and risk-stratified HIV transmission models separately calibrated to local data from a high-incidence (Atlanta, USA) and a low-incidence (Montréal, Canada) North American setting. PrEP coverage of HIV-negative MSM was simulated to increase from 6% to 15%, 30%, 40% or 50% (Montréal) or from 29% to 40% or 50% (Atlanta), within 5 or 10 years, with 0%, 15%, 30%, 50% or 100% of current TDF/FTC users switching to CAB-LA. Costing took a healthcare payer perspective and included PrEP pharmaceuticals, PrEP programmatic costs and HIV-related care. Atlanta scenarios considered oral PrEP acquired at average recent market prices (primary analysis), and both settings modelled universal acquisition at the lowest available generic price (LAGP). Simulations were compared to baseline projections without CAB-LA-based expansions over 20 years, with costs and disability-adjusted life years (DALYs) discounted 3% annually. Incremental cost-effectiveness ratios (ICERs) of expansions were assessed against a $100,000 per DALY averted threshold.

resultsIn Atlanta, scenario median ICERs at recent prices ranged from $141,600 (90% CI $60,100-$256,000) to $203,800 ($99,300-$359,200) per DALY averted. All uncertainty intervals covered $100,000. Under universal LAGP TDF-FTC, median ICERs ranged from $255,800 ($112,900-$452,30) to $370,700 ($172,200-$669,100). The strongest expansion scenarios were expected to remain cost-effective until approximately $2800/dose, or approximately $1350 with universal LAGP TDF/FTC. In Montréal, scenarios had median ICERs from $920,000 to $2,540,000, excluding dominated runs.

conclusionsIn a high-incidence Atlanta MSM population, CAB-LA-based PrEP expansions are not projected to be cost-effective, though a minority of simulations achieved cost-effectiveness. However, lower prices could achieve cost-effectiveness. In a low-incidence Montréal MSM population, broad expansions are not expected to be cost-effective at modelled prices. Prioritizing CAB-LA to Montréal MSM facing access, adherence or persistence barriers to oral PrEP warrants a cost-effectiveness assessment.