The ultimate goal of antiretroviral therapy for HIV is to cure the patient of infection. Since this objective is not yet achievable, the second target is to provide a simple, inexpensive, well-tolerated regimen that is able to control the infection for a long period of time, even indefinitely. Unfortunately, even this objective is elusive, and current therapies are generally complex, rigid, and burdened by toxicities. They are time-limited in their efficacy, but the length of time the therapies remain effective has been steadily improving, particularly for patients who adhere to their regimens. Much of the recent progress has been attributable to a better understanding of HIV biology, which has made drug selection and use more rational. This chapter will summarize the currently available antiretroviral drugs and outline some basic strategies for their use.
The biology of HIV and antiretroviral therapy
Chapter 2 describes the HIV life cycle and outlines the steps in the life cycle targeted by antiretroviral drugs, including drugs currently in clinical use, those under development, and those which did not prove to be clinically useful. The viral targets of antiretroviral agents are outlined in Chapter 2, Figures 2.2 and 2.4, and Table 2.1. The antiretroviral drugs in current clinical use inhibit either the viral reverse transcriptase, which makes a cDNA copy of the viral genomic RNA; the viral protease, which cleaves the viral Gag and Gag-Pol polyprotein into the subunits required to make a fully mature, infectious virion; or block the fusion of the viral envelope with the plasma membrane of its would-be future host cell.