Preexposure Prophylaxis—a New Addition to the Armamentarium Against Human Immunodeficiency Virus

Abstract

At the end of 2015, 36.7 million people worldwide were living with human immunodeficiency virus (HIV)/AIDS with 2.1 million newly diagnosed. The development of antiretroviral therapy was a remarkable milestone that vastly transformed the manner in which HIV/AIDS patients were managed. The introduction of preexposure prophylaxis (PrEP) ushers in a new era that could again redefine the course of this global epidemic. Daily administration of oral combination tenofovir disoproxil fumarate-emtricitabine (TDF-FTC) and TDF alone as PrEP has demonstrated efficacy in preventing new HIV cases in a number of trials. The results of these studies represent major advances in preventing HIV acquisition and provide convincing evidence that widespread use of daily oral TDF-FTC by heterosexuals, men, women, and intravenous drug users and use of vaginal TDF is safe and effective. Low adherence has been cited as reason for failures in a few studies and poses a significant challenge when implementing PrEP in the real world in highly diverse communities. Several studies investigating a variety of strategies for PrEP delivery are underway to mitigate treatment challenges. Emerging strategies include the use of alternative antiretrovirals, novel formulations, and routes of administration, as well as dosing regimens. This article reviews literature on prior studies, current concerns and challenges, and future strategies for implementing effective PrEP.