A landmark study evaluating the safety and efficacy of indinavir (Crixivan) in combination with AZT and 3TC in patients with advanced AIDS and CD4 counts < 50 cells/mm3 was presented at the 4th National Conference on Human Retroviruses and Opportunistic Infections in Washington D.C. by Dr. Martin Hirsch from Massachusetts General Hospital. The study was a randomized, double-blind 24 week trial which enrolled 320 patients with at least 6 months of prior AZT therapy and a median CD4 count of 15 cells/mm3. Patients were randomized to receive Crixivan (800 mg every 8 hours) in combination with AZT (200 every 8 hours) and 3TC (150 mg twice daily), Crixivan monotherapy or AZT + 3TC. All patients were protease inhibitor and 3TC naive. After 6 months of follow-up 65% of 85 patients evaluable for analysis in the triple combination arm had experienced declines in viral load to below the level of detection (500 copies/ml), whereas 2% on indinavir monotherapy and none of the patients in the AZT + 3TC arm experienced HIV levels below the level of detection. The median decreases in viral load at 24 weeks were -2.2 logs for the triple therapy arm, -0.5 for the Crixivan monotherapy arm and -0.2 for the AZT + 3TC arm. Median increases in CD4 counts at 24 weeks were + 84 cells for the triple combination, + 65 cells for Crixivan monotherapy and zero cells for AZT + 3TC. Overall more patients withdrew from the AZT + 3TC arm of the study (35), as compared to the other two arms (23 and 17 for the Crixivan monotherapy and triple combination arms, respectively). Only one patient developed a kidney stone which required drug discontinuation. The study has been extended and all patients have been offered triple combination therapy.