US Army claims `modest' success with AIDS vaccine trials in Thailand

An investigational vaccine trial in Thailand by the US Army and the National Institute of Allergy and Infectious Diseases has claimed encouraging results with the vaccine being well tolerated and showing a modest effect in preventing HIV infection in a clinical trial involving more than 16,000 adult participants.

An analysis of the trial data, according to the trial sponsor, the Surgeon General of the US Army, the prime-boost investigational vaccine regimen was safe and 31 per cent effective in preventing HIV infection.

"These new findings represent an important step forward in HIV vaccine research," says Anthony S Fauci, MD, director of the National Institute of Allergy and Infectious Diseases (NIAID), part of the NIH, which provided major funding and other support for the study.

"For the first time, an investigational HIV vaccine has demonstrated some ability to prevent HIV infection among vaccinated individuals. Additional research is needed to better understand how this vaccine regimen reduced the risk of HIV infection, but certainly this is an encouraging advance for the HIV vaccine field," he added.

The Thai Phase III HIV vaccine study, also known as RV144, opened in October 2003. The placebo-controlled trial tested the safety and effectiveness of a prime-boost regimen of two vaccines: ALVAC-HIV vaccine (the primer dose), a modified canarypox vaccine developed by Freench pharma giant Sanofi Pasteur, and AIDSVAX B/E vaccine (the booster dose), a glycoprotein 120 vaccine developed by Vaxgen Inc, and now licensed to Global Solutions for Infectious Diseases (GSID), based in South San Francisco, California.

The vaccines are based on the subtype B and E HIV strains that commonly circulate in Thailand. The subtype B HIV strain is the one most commonly found in the United States.