Annual AIDS vaccine conference to stress progress, partnership, and perseverance

By Regina McEnery

The scientific terrain of HIV vaccine research has changed a lot in recent years, as other new prevention strategies have come into their own. So, as the four-day conference looks beyond 2013, its agenda will entertain a number of discussions on the possible synergies between vaccines, microbicides, and ARV-based prevention. Jointly sponsored by the Global HIV Vaccine Enterprise and HIVACAT, the Catalan Program for HIV Vaccine Development, the conference is to be held Oct. 7-10 at the International Convention Center in Barcelona.

The fate of adenovirus vector vaccine candidates is likely to dominate discussion as well, beginning with an opening night talk by Magda Sobieszczyk. An assistant professor of clinical medicine at Columbia University Medical Center, Sobieszczyk will be providing highlights and lessons learned from the HVTN 505 trial, which was recently terminated for futility (see IAVI Report blog, Large AIDS Vaccine Trial Shudders to a Halt, April 26, 2013). Duke University scientist Georgia Tomaras will provide antibody profiles from the HVTN 505 study and compare them to those from RV144, the only AIDS vaccine trial to demonstrate any measure of efficacy. In that trial, which had 16,000 participants, a combination of two vaccine candidates administered sequentially in what is called a prime-boost regimen lowered the rate of HIV infection by about 31%.

There will also be a roundtable discussion on the importance of retaining and following clinical trial participants long after the conclusion of a study, a point that became clear following the Phambili study, which was halted in 2007, and drew fresh scrutiny this year (see VAX May 2013 Global News). Finally, the HIV Vaccine Trials Network (HVTN), which sponsored the HVTN 505 trial, will provide a meta-analysis of results from vaccine trials in which adenoviruses have been used as vectors.

Another hot topic at the vaccine conference will be the burgeoning field of structure-based immunogen design. That includes a four-hour satellite session organized by The Scripps Research Institute about the structure of the HIV glycoprotein trimer—or “spike”—which the virus uses to invade its target cell. This extraordinarily complex protein, which protrudes from the surface of HIV, has long resisted structural analysis. But images of this protein complex are becoming clearer, thanks to new imaging technologies and strategies. The satellite session in Barcelona will cover the promise of this structural work—and some related controversies.

And scientists from the Military HIV Research Program are expected to present preliminary data from the RV305 trial, an immunogenicity study that began in 2012 and evaluated the impact of an additional protein boost in volunteers who participated in the RV144 trial (see VAX Sep. 2009 Spotlight article, First Evidence of Efficacy from Large-Scale AIDS Vaccine Trial).

The vaccine conference has broken some new records this year even before it has begun. More than 325 young and early career investigators applied for scholarships, and more than 600 abstracts were submitted for consideration, about 100 more than usual. About 1,000 people are expected to attend the meeting.

Barcelona also brings to a close the single-themed focus of the meeting. Starting in 2014, attendees who converge Oct. 28-31 in Cape Town, South Africa, will get a full course of microbicide and ARV-based prevention research, along with the usual dose of vaccine science the meeting has served up every year.