The idea was to prime the immune system with the first vaccine and then boost it with the second. Researchers hoped to elicit both antibodies to HIV and killer T cells that would destroy the virus.
Both medications contained HIV fragments from two strains, one is common in Europe and North America -- and another strain is found in Thailand and Southeast Asia.
The trial was controversial when it started, largely because of the previous failure of the AIDSVAX component.
But some believe this could be a first step toward an effective vaccine.
"It's promising in that there is a significant effect," said Dr. John Bartlett, chief of the division of infectious diseases at the Johns Hopkins Medical Institutions, and chair of the Infectious Disease Society of America's task force on antimicrobial availability. "It gives a clue about what might work so that the second generation can be tested."