NIAID Begins Trial of HIV Vaccine Targeting Three Subtypes Responsible for 90% of Infections Worldwide

Researchers at NIAID's Dale and Betty Bumpers Vaccine Research Center yesterday began clinical trials for a new HIV vaccine aimed at the "three most globally important" HIV subtypes, or clades, which are responsible for 90% of all HIV infection worldwide, according to a NIAID release. The vaccine being tested is a DNA vaccine that uses parts of four HIV genes, three of which are "modified versions" of the HIV genes gag, pol and nef from HIV subtype B. The other component is taken from the HIV gene env, which combines modified env from clades A, B and C. Although these gene fragments can elicit a response from the body's immune system, they are not able to change into active virus, meaning a person cannot be infected with HIV from the vaccine, according to Dr. Gary Nabel, head of the VRC. He added, "Any HIV vaccine must hit a constantly moving target. Essentially, we are trying to enlarge that target through a multiclade vaccine." For the double-blind trial, researchers will enroll 50 healthy, HIV-negative men and women between the ages of 18 and 40, who will be vaccinated in a series of increasing doses with either the test vaccine or an inactive saline solution. During the year-long study, researchers will monitor the vaccine's safety and watch for any immune response to the vaccines. NIAID's HIV Vaccine Trials Network plans to expand trials to several U.S. cities, as well as to sites in Haiti and South Africa (NIAID release, 11/13). Nabel said, "This trial begins a process that we hope will culminate in a globally effective HIV vaccine" (Xinhua News Agency, 11/13).

VaxGen's AIDSVAX
In other vaccine news, Reuters Health yesterday profiled VaxGen's AIDSVAX trial, the first-ever HIV vaccine efficacy trial, the results of which are expected in early 2003. The vaccine is currently in Phase III clinical trials, the final stage of testing before a drug company can apply for FDA approval (Fox, Reuters Health, 11/13).