The HIV vaccine candidate produces a robust immune response in healthy adults



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An experimental vaccine regimen against HIV-1, adenovirus mosaic serotype 26 (Ad26) was well tolerated and produced immune responses against HIV in humans and rhesus monkeys, according to the results of one trial Clinical Phase 1 / 2a published in the Lancet .

In the APPROACH trial, 393 people at low risk of HIV were recruited to receive either one of seven vaccine combinations or a placebo; they received 4 vaccinations for 48 weeks. To stimulate an initial immune response, each participant received an injection of Ad26.Mos.HIV at the advent of the study and 12 weeks later. Two additional vaccinations were administered at weeks 24 and 48 using combinations of Ad26.Mos.HIV or a different vaccine component called Vaccinia Modified Ankara (MVA) with or without 2 different doses of the clade gp140 protein. C of HIV. The researchers found that all vaccine regimens were well tolerated and could induce anti-HIV immune responses in healthy individuals. Similar systemic reactions have been reported in all groups included in the trial.

In a parallel study, the efficacy of the candidate was evaluated in 72 rhesus monkeys with simian human immunodeficiency virus (SHIV) similar to HIV affecting monkeys. The Ad26 / Ad26 plus gp140 vaccine candidate induces the greatest immune responses in humans and provides complete protection in two-thirds of the monkeys after six challenges.

"These results represent a milestone," said Dan Barouch, MD, professor of medicine at Harvard Medical School, director of the Center for Virology and Vaccine Research, Beth Israel Deaconess Medical Center, and head of the Study in a statement . "This study demonstrates Ad26 prime mosaic, Ad26 plus gp140 HIV vaccine candidate induces robust immune responses in humans and monkeys with comparable magnitude, kinetics, phenotype, and durability, and provides 67% protection against viruses in monkeys. "

at week 28. The safety and immunogenicity were also evaluated at week 52.

Dosing regimens This study is based on vaccines" unique "mosaics" that use fragments of different HIV viruses and that combine to trigger immune responses against various strains.The study participants were recruited from a dozen clinics in East Africa, in South Africa, Thailand, and the US This diet is one of 5 experimental designs of HIV-1 vaccines that have progressed to efficacy trials in humans in 35 years. [19659002] According to the authors, some of the limitations of the study include the lack of definitive immunological measurement to predict HIV-1 in humans and that "the relevance of vaccine protection in rhesus monkeys to the Clinical efficacy in humans "is not clear.

"These results must be interpreted with caution. the ability to induce specific immune responses to HIV does not necessarily indicate that a vaccine will protect humans from HIV infection, "concludes Dr. Barouch.

The Phase 2b trial was initiated in southern Africa to evaluate the safety and effectiveness of the vaccine. in 2,600 women at risk, the results of this trial will demonstrate whether the vaccine has the potential to protect against contraction of HIV.

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