Traversing the AIDS Vaccine Terrain in Vancouver

July 23, 2015

Amid the excitement in Vancouver over the START and PrEP results, conference-goers did hear several specific updates on progress in HIV vaccines. Here are a few highlights advocates seeking to track the vaccine field should check out.

One great place to start is with the slides from a presentation on delivered by Dr. Anthony Fauci, head of the US National Institute of Allergy and Infectious Diseases. The slide set, with Dr. Fauci’s instantly-recognizable font size and simple layout, has some familiar images from previous presentations—including the always-useful depiction of the HIV prevention continuum—but also provides crystal-clear explanations of the “empirical/intuitive” and “rational” pathways of vaccine development focused on producing antibodies against the virus. In the former category is the RV144-like regimen moving ahead in trials in southern Africa. In the latter are broadly neutralizing antibodies being studied in passive immunization and preclinical work. A commentary in Science published just after the conference by Dr. Facui and Dr. Hilary Marston provides additional perspective and depth to the discussion. 

RV144 was the name of the 16,000 person trial that took place in Thailand and found evidence of modest protection in data released in 2009. Just before Vancouver got underway, the research team involved with the trial published new data on why this protection might have occurred. Every person has a distinct genetic make-up that affects how our immune systems function. In analyzing volunteers’ HLA gentoypes (these contain the “instructions” for proteins that help regulate the immune system), the investigators identified specific genetic signatures associated with vaccine efficacy. This type of research can help scientists figure out how to make vaccines work even more effectively in the future.

The rational pathways also got attention at a Wednesday session, “Advances in B-cells and Antibodies,”” including an update from Joseph Jardine of Scripps Research Institute, on upstream work aimed at increasing the potency of the VRC-01 broadly neutralizing antibody. VRC-01 is a purified form of a potent antibody isolated from an individual living with HIV; it is in Phase I trials in adults and, as described at a cure satellite symposium, a safety and pharmacokinetic trial in infants is now enrolling.

Vaccine science is heady stuff and presentations of the hill-and-valley contours of antibodies can seem very far from the rural and urban landscapes where people live, work, encounter HIV and perhaps enroll in trials. A presentation on hypothetical willingness to participate in vaccine trials from the Perinatal HIV Research Unit in Soweto, South Africa, focused on that terrain. Pointing out the urgent need for HIV prevention strategies in 15-24 year olds, particularly young women, the research team asked people in this age group whether they would enroll in a trial. About half would, saying altruism would motivate them. About a quarter said that they wouldn’t, because they were worried about “becoming ill.”

Bridging the gap between landscapes of molecules and townships has always been the work of AIDS vaccine research. This bridging was highlighted by Glenda Gray, president of the South African Medical Research Council, in her Wednesday plenary on Advancing HIV Vaccines into Efficacy Studies—and though it was a quiet year, we can clearly expect more updates in Durban 2016 as the South African trials continue and basic science also proceeds.