The treatment of HIV infection is one of the most rapidly evolving fields in medicine. Advances in basic research, the development of new technologies for monitoring therapy, the continuous introduction of new drugs into clinical practice, and the dissemination of the results of recent trials all raise expectations and suggest new strategies for optimal management of HIV disease. It is clear that, as more antiretrovirals become available, clinicians will face more and more complex decisions on when to start antiretroviral treatment and with what combinations and, in the long term, how to define therapeutic failure.

Although analysis of the relation between drug resistance and treatment failure has in the past been complicated by concomitant interaction with other virological factors, the emergence of drug resistance appeared, until a few years ago, to be the inevitable consequence of all antiretroviral treatments and the major cause of therapeutic failure. Because of expanded knowledge of the dynamics of HIV replication that has become available within the last two to three years, we now understand that the rapid emergence of resistance is a direct consequence of the incomplete viral suppression obtainable with single or double nucleoside therapy.

Indeed, in just a very short time, new virological concepts have emerged and results from trials with potent combinations have demonstrated that drug resistance can be at least delayed, if not completely overcome, by appropriate treatment strategies.

Contents:

• Definition and Measures of Resistance
• General Mechanisms of Resistance
• Resistance Patterns
• Clinical Implications, Clinical Guidelines
• Further Reading