In this open-label, single-arm study, HIV-1 infected patients who had, at study entry, a viral burden of at least 500 copies/mL despite 20 weeks of treatment with a protease inhibitor receive combination therapy with three antiretroviral agents that were investigational at the start of study but have since been approved: abacavir, amprenavir, and efavirenz. At the end of 16 weeks, the addition of other antiretroviral agents to the study regimen was permitted. This was originally a multi-center study, but it has been closed at all other sites. It remains open at the NIH to continue to provide therapy to subjects who have received benefit as determined by a decline in viral load from baseline. Safety and viral load data continue to be collected.