AIDS: Saquinavir, developed by Hoffmann-LaRoche under the trade name Invirase, is the first protease inhibitor to be approved by the Food and Drug Administration (FDA) for use in combination with one or more unspecified nucleoside analogs. Rifampin should not be taken with saquinavir, and rifabutin should be only cautiously used in combination with saquinavir. Protease inhibitors have shown T-cell increases and viral load reductions similar to AZT when taken at the present low dosage. Research is being done on a new formulation which would deliver more effective amounts. The cost of saquinavir and other new drugs may be prohibitive, especially as the standard treatment changes from one drug (AZT) to combinations of drugs. Physicians and patients should call the Roche HIV Therapy Assistance Program for more information.