The antiretroviral potency of DAPD varies among antiretroviral-experienced patients. In vitro studies indicate that the potency of DAPD can be markedly increased by the addition of MMF. Preliminary data indicate that MMF is well tolerated in patients with advanced HIV-1 disease. However, there is currently no clinical data on the activity of DAPD combined with MMF. This study will be the first to evaluate the addition of DAPD and MMF to a patient's current antiretroviral therapy.