Interest exists in the development of antiretroviral agents that possess different mechanisms of action from nucleoside analogs such as AZT. U-87201E is a non-nucleoside reverse transcriptase (RT) inhibitor that has demonstrated activity against HIV-1; however, an emerging characteristic of non-nucleoside RT inhibitors is the development of rapid resistance to HIV isolates. Whether this resistance can be prevented in the presence of nucleoside analogs such as AZT and ddI has yet to be determined.