AN unlikely speaker took the stage this morning at the M2010 Microbicides: Building Bridges in HIV Prevention plenary, a prominent HIV vaccine researcher.
Dr Susan Buchbinder, the director of HIV research at the San Francisco Department of Public Health, presented 10 lessons from vaccine studies in which she has been involved including the STEP/Phambili Phase III efficacy trial.
Her lessons were:
# 10: Good science often yields surprising results. The findings in the RV144 Thai trial were unexpected, she said. The vaccine only provided weak cell-mediated immunity and not broadly neutralizing antibodies, yet it offered some protection against infection (an estimated 31%).
#9: Results take time to process and that analyses of the STEP/Phamibili data down the line have yielded some clues. For example, in the first three months the vaccine seemed to suppress the virus even though this effect was transient.
#8: It takes many villages for a trial: more than 16 000 volunteers were recruited for the Thai trial which was well conducted.
#7: Statistics are confusing to almost all of us. Buchbinder reported on the different analyses of the Thai trial result statistics which were released last year -and generated much controversy.
#6: Behaviour change is difficult. This is particularly relevant for microbicides, in which trials have shown that it is challenging to get volunteers to use the product appropriately.
#5: Mucosal responses are important and difficult to measure.
#4: Clinical efficacy trials are an important part of the discovery process (whether they yield the hoped for outcome or not). They provide data that cannot be gathered from non-human primates (like rhesus macaques monkeys).
#3: Transparency yields many rewards, in scientific circles and in communities. Buchbinder said the Thai researchers released their findings first to the community and subsequently opened up their data and specimens to the broader scientific community, which was a positive move.
#2 : There will be no silver bullet for HIV prevention any time soon but combined approaches can have an effect.
#1: Discovery is a multi-step process and all partners must work together. “We need multiple pieces to build combined prevention strategies,” she declared.