The Thai Trial and Other HIV Vaccine Studies

Segment Description: Ian Frank, MD, Professor of Medicine at the Perelman School of Medicine, gives an overview of different HIV vaccine efforts in recent years and on the horizon.

Interview Transcript (modified slightly for readability):

Frank: We have one vaccine study that's been a success. That's called the Thai vaccine study or RV144. It showed a modest rate of protection from HIV acquisition in individuals who got a combination vaccination strategy. Unfortunately, we tried to improve upon those vaccine components with next generation products. And we evaluated that vaccine combination in a trial called HVTN702 (vaccine trial network 702). Unfortunately, that strategy didn't work. There were as many infections and individuals who got the vaccine as an individuals who got the placebo. We don't yet know why that may be the case. It may be that in the 702 study individuals engaged in higher risk behaviors, and maybe the vaccine couldn't overcome the numbers of exposures in that particular population. That study was done in southern Africa.

However, there are a lot of exciting newer generation vaccine products that we're just starting to explore. There's reason to be optimistic about some of these newer strategies that will hopefully be able to elicit a neutralizing antibody response. That's the kind of response we now think, is probably key to prevent people from becoming HIV-infected.

There's a prototypic study of a broadly neutralizing monoclonal antibody as PrEP [pre-exposure prophylaxis]. Some people call it a vaccine study, but it's really a PrEP study, giving a broadly neutralizing monoclonal antibody to people to try to have them show the kind of immune response we think is going to be protective. And there are 2 studies, 1 focusing on women in southern Africa, 1 focusing on men who have sex with men and transgender women in the Americas that are testing this potential strategy. If these studies are successful, then we'll at least understand the kind of immune response that we want to generate with an effective preventative vaccine. And then the challenge will be to develop the products that elicit that kind of immune response.