Protease inhibitors shine in triple combinations.

Ritonavir, a protease inhibitor, demonstrated strong antiviral activity when combined with AZT and ddC at dosage levels of 1200, 600 and 2.25 mg respectively. Six-month therapy resulted in a median CD4 count increase that was nearly double from baseline, and significant viral load reductions that were sustained throughout the study. Ritonavir was generally well tolerated. A study using AZT and 3TC with an experimental protease inhibitor, indinavir, also greatly reduced viral loads. The effects lasted throughout the six-month treatment period. A specific HIV protease gene that contributes to the emergence of resistance during treatment with ritonavir has also been identified.