Protease inhibitors are highly efficacious in the treatment of HIV-1 disease. Current drugs, however, are associated with a high incidence of adverse effects as well as metabolic complications such as lipodystrophy and hyperlipidemia. At the same time, though, a causal relationship linking these complications to the use of protease inhibitors remains to be established. Studies have shown APV to be well tolerated and effective in reducing plasma HIV-1 RNA levels. The safety profile of APV suggests it may offer therapeutic potential in subjects developing intolerance to other protease inhibitors.