Among men who have sex with men, the use of long-acting injectable pre-exposure prophylaxis, or PrEP, to prevent HIV infection has the potential to reduce HIV transmission more than oral PrEP, according to the results of a modelling simulation published in The Lancet HIV.

“PrEP use among [men who have sex with men (MSM)] in the United States has increased, but its uptake in this population has been slow. Additionally, an individual must take at least four doses per week to achieve intracellular drug concentrations consistent with 96% reduction in risk of HIV infection,” Brandon D.L. Marshall, PhD, associate professor of epidemiology in Brown University’s School of Public Health, and colleagues wrote.

For their study, Marshall and colleagues simulated HIV transmission to a network of 11,245 MSM in Atlanta and estimated the efficacy of long-acting injectable PrEP using pharmacokinetic data from safety trials and raw data from macaque model studies. They evaluated the effect of long-acting injectable PrEP on the cumulative number of new HIV infections over the course of 10 years from 2015 to 2024. The effects were compared with two other scenarios: no PrEP availability and using daily oral PrEP exclusively at various coverage levels.

At any level of coverage, long-acting injectable PrEP outperformed daily oral PrEP in decreasing the cumulative number of new HIV infections between 2015 and 2024, according to the researchers. At 35% coverage, long-acting injectable PrEP prevented 1,044 infections, compared with daily oral PrEP, which prevented 792 — a 16% relative decrease in cumulative incidence, the researchers reported.

“The relative benefit of long-acting injectable PrEP was sensitive to the assumed efficacy of injections received every 8 weeks, discontinuation rates, and terminal drug half-life,” Marshall and colleagues wrote. Read more via Healio