Marta Bárcena Castro, Inés de Cáceres Renovell, María Cacicedo Jaroszynska and Carmen Candilejo Deleyto.
September 17, 2018.
In the continuous research on a HIV vaccine in order to decrease the HIV pandemic -37 million people around the world have HIV/AIDS and 1.8 million new cases are diagnosed every year-, an unprecedented HIV-1 vaccine concept is being tested and the results from a phase 2b efficacy trial, which took place in southern Africa, will be known soon.
What distinguish this HIV-1 vaccine candidate from previous ones is that, contrary to the others, this vaccine is not limited to specific regions of the world, but combines different pieces of different HIV viruses, resulting in a “mosaic” vaccine which triggers immune responses against a wide variety of HIV strains, and this is the underlying reason for its efficacy.
The results of the previous phase, phase 1/2a clinical trial, demonstrated that this mosaic vaccine candidate induce robust immune responses in human and monkeys with comparable data. The fact that it has provided 67% protection against viral challenge in rhesus monkeys has stand out among others. Nevertheless, the ability to induce HIV-specific immune responses does not imply that a vaccine will protect humans from HIV infection. This protection will be either demonstrated or rejected by the results of the phase 2b efficacy trial.
If the results are satisfactory, this would mean that HIV-1 vaccine candidate will become the second vaccine concept out of six to prove being protective against the virus in an efficacy trial in the 35 years of global HIV/AIDS epidemic. Although the first vaccine concept that provided evidence of protection lowered the rate of human infection by 31%, its effect was considerated too small to move forward the vaccine to common use.
Dan Barouch et al. Evaluation of a mosaic HIV-1 vaccine in a multicentre, randomised, double-blind, placebo-controlled, phase 1/2a clinical trial (APPROACH) and in rhesus monkeys (NHP 13-19). The Lancet, 2018.
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