The promise and pitfalls of long-acting injectable agents for HIV prevention.

PURPOSE OF REVIEW Preexposure prophylaxis for HIV prevention is highly effective when taken as prescribed. Adherence to required dosing regimens for protection may pose challenges. Long-acting agents for HIV prevention may have the potential to improve adherence via favorable pharmacokinetics supportive of infrequent dosing. This review focuses on the potential benefits and considerations for the study and use of 2 long-acting injectable agents, cabotegravir (GSK1265744LA, CAB LA) and rilpivirine (TMC278LA, RPV LA), for use as chemoprophylaxis for HIV prevention. RECENT FINDINGS Oral RPV is United States Food and Drug Administration approved for HIV treatment (in combination with other antiretrovirals). Both CAB LA and RPV LA are currently in phase 2a safety/tolerability/pharmacokinetic studies in anticipation and support of future efficacy evaluation. Both agents have favorable pharmacokinetics, and use is complicated by injection site reactions. SUMMARY Long-acting injectable formulations, if safe and well tolerated, may improve pharmacokinetic coverage of exposures to HIV infection. Complexities around safety, tolerability, and starting/stopping protocols require careful consideration.