Recent studies indicate that the use of triple-combination therapy, in particular the combinations of reverse transcriptase inhibitors and a protease inhibitor, can result in a significant decrease in plasma HIV-1 RNA levels and an increase in CD4 cell count. Continued follow-up of patients taking triple-combination drug regimens has in some cases demonstrated sustained suppression of plasma HIV-1 RNA levels for up to 18 months. Furthermore, despite the potent antiviral effect of some triple combinations, a percentage of patients continue to have measurable levels (more than 500 copies/ml) of HIV-1 RNA in plasma, even when treated with a combination of 2 reverse transcriptase inhibitors and indinavir. Over time, some patients experience a rebound of plasma HIV-1 RNA for reasons that are not well understood. [AS PER AMENDMENT 7/8/98: Randomization to 2 dose levels may allow more patients to derive therapeutic benefit from Preveon by minimizing adverse effects.]