Studies of antiretroviral therapy in the Multicenter AIDS Cohort Study.

The Food and Drug Administration has been increasingly reliant on surrogate end points to fast-track the licensing of antiretroviral agents. As a result, critical information, such as long-term adverse events, clinical progression rates, survival, and development of resistance, are not available before licensure. Therefore, phase IV studies conducted in large community- and/or clinic-based cohorts will become essential to fill in the gaps in the clinical knowledge base for many of these drugs, and observational cohort studies of HIV-infected patients have been used to address many of these questions. In addition to studies of antiretroviral impact on adverse events and outcomes, such cohorts can provide valuable data on utilization patterns, physician prescribing patterns, and the important issue of patient compliance with increasingly complicated drug regimens.