Antiretroviral therapy: evaluating the new era in HIV treatment

Tools for evaluating antiretroviral therapy are still evolving. Key components are available such as the laboratory assays themselves, but results from these assays are being analyzed and presented inconsistently, making interstudy comparisons difficult or impossible. In part, the problems in analysis and presentation reflect a lack of completed clinical trials in which new laboratory methods such as RNA copy numbers can be validated. Survival is the clearest valid end point in clinical trials of antiretroviral drugs. Beyond life and death, the next most important issue is quality of life. Because of the difficulty in agreeing what "quality of life" means, and the even greater problems measuring such an abstract concept, in most cases assessments are made of more quantifiable clinical elements: cognitive and motor function, growth, and the frequency of opportunistic infections. Laboratory markers of disease progression are very quantifiable but have meaning only when they predict clinical outcome. There is a consensus that CD4+ counts, CD4+ percentages, and HIV copy numbers measured by RNA PCR are important. There is not, however, a consensus approach to interpretation of data from any of these markers of HIV disease, particularly because the interpretation may vary based on the patient's level of clinical disease. With time and more clinical trials with which to clarify their use, these tools should become more uniformly applied, at which point cross-study comparisons might be possible. Progress is already being made in the development of new antiretroviral therapies, and with improved evaluation techniques the evolution of new anti-HIV treatments should become an even more efficient process.