The AVANTI trials were designed to assess the effect of combination antiretroviral therapies on viral load as measured by RNA-PCR as well as their safety and tolerance, providing information on promising drug regimens. AVANTI I evaluated zidovudine plus 3TC versus zidovudine plus 3TC plus loviride.
This was an international, double-blind (neither doctors nor volunteers knew which therapy volunteers received), comparative trial were volunteers, with CD4 count between 150 and 300 cells/mm3, were randomized to receive either AZT(200mg td)/3TC(300mg bd) or AZT/3TC/loviride(100mg td). The study compared the duration of reduction in viral load and the safety.
One hundred antiretroviral naive patients were randomized (50 per arm). The mean CD4 count was 270 for both arms of the study. The mean viral load was 4.8 and 4.9 respectively for the two-drug arm and the three-drug arm.
The median increase in CD4 count over 52 weeks was 54.8 in the two-drug arm and 98.5 in the three-drug arm. The maximum increase from baseline in CD4 count was 69 in the two-drug arm compared to 127 in the three-drug arm.
The median decrease in viral load over 52 weeks was 1.3 for the two-drug arm and 1.6 for the three-drug arm. The maximum decrease from baseline in viral load was 1.9 in the two-drug arm and 2.1 in the three-drug arm.
A statistically significant difference was observed in viral load and CD4 count in the AZT/3TC/loviride group. There was a superior decrease in viral load between week 8 and 28. At week 8, more than 50% of patients receiving AZT/3TC/loviride had viral loads below 500 copies/ml. There was a more pronounced and sustained effect on CD4 count up to 58 cells at 52 weeks. Both treatment arms were well tolerated.