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Source: Sherry Young / Fotolia
A new study published in The Lancet shows that an experimental scheme of vaccine against HIV-1 is well tolerated and generates comparable and robust immune responses against HIV in healthy adults and rhesus monkeys. In addition, the candidate vaccine has protected against infection with an HIV-like virus in monkeys.
Based on the results of this phase 1 / 2a clinical trial involving nearly 400 healthy adults, a phase 2b trial was initiated in southern Africa. determine the safety and efficacy of the HIV-1 vaccine candidate in 2,600 women at risk of contracting HIV. This is one of five experimental designs of HIV-1 vaccines that have progressed toward efficacy trials in humans over the 35 years of the global HIV / AIDS epidemic. AIDS.
world. The experimental designs tested in this study are based on "mosaic" vaccines that take pieces of different HIV viruses and combine them to trigger immune responses against a wide variety of HIV strains
. "These results represent an important step. Ad26 prime mosaic, Ad26 plus gp140 stimulates HIV vaccine induces robust immune responses in humans and monkeys with comparable magnitude, kinetics, phenotype and durability and 67% protection against viruses in monkeys Professor Barouch said, "These results need to be interpreted with caution: an HIV vaccine is unprecedented, and the ability to induce specific HIV immune responses does not necessarily indicate that a vaccine will protect humans from HIV infection. We look forward to the results of the vaccine. Phase 2b efficacy test called HVTN705, or "Imbokodo", which will determine whether this vaccine will protect humans against HIV infection or not.
Nearly 37 million people are living with HIV / AIDS, with an estimated 1.8 million new cases each year, a safe and effective preventative vaccine is urgently needed to stem the HIV pandemic.
In the 35 years of the HIV epidemic, only four concepts have been tested in humans. a primitive anticoagulant vaccine Gp120 tested in the RV144 trial in Thailand lowered the rate of human infection by 31 percent, but the effect was considered too low to advance the vaccine to a use
A major obstacle to the development of HIV vaccine has been the lack of direct comparability between clinical trials and preclinical studies. To address these methodological issues, Barouch and colleagues evaluated the HIV vaccine candidate. 1 based on serotype 26 (ad26) adenoviral mosaic will direct parallel clinical and preclinical studies to identify the optimal vaccine regimen for HIV in order to advance in clinical trials of efficacy.
uninfected adults (aged 18 to 50 years) from 12 clinics in East Africa, South Africa, Thailand and the United States between February 2015 and October 2015. Volunteers were randomly assigned to one of seven vaccine combinations or a placebo. four vaccinations within 48 weeks.
To stimulate, or "prime", an initial immune response, each volunteer received an intramuscular injection of Ad26.Mos.HIV at the start of the study and again 12 weeks later. The vaccine containing antigens ENV / Gag / Pol "mosaic" was created from many strains of HIV, administered with the aid of a non-replicating common cold virus (Ad26).
To "boost" the immune response level of the body two additional vaccinations at weeks 24 and 48 using various combinations of Ad26.Mos.HIV or a different vaccine component called Vaccinia Modified Ankara (MVA) with or without two different doses of clade C envelope protein gp140 HIV containing an adjuvant aluminum.
The results showed that all vaccine regimens tested were able to generate anti-HIV immune responses in healthy individuals and were well tolerated, with a similar number of local and systemic reactions reported in all groups, including severity. was mild to moderate. Five participants reported at least one vaccine-related Grade 3 adverse event, such as abdominal pain and diarrhea, postural dizziness, and back pain. In a parallel study, the researchers evaluated the immunogenicity and protective efficacy of the same Ad26-based mosaic vaccine regimens in 72 rhesus monkeys using a series of repeated challenges with the HIV virus. Simian-human immunodeficiency. (SHIV) – an HIV-like virus that infects monkeys.
The vaccine candidate Ad26 / Ad26 plus gp140 induces the greatest immune responses in humans and also provides the best protection in monkeys, which provides complete protection against SHIV infection in monkeys. third of vaccinated animals after six challenges.
The authors note several limitations, including the fact that the relevance of vaccine protection in rhesus monkeys to clinical efficacy in humans remains unclear. They also note that there is no definitive immunological measurement known to predict protection against HIV-1 in humans.
Writing a related commentary, Dr. George Pavlakis and Dr. Barbara Felber of the National Cancer Institute of Frederik, Maryland The United States states: "Efficacy studies are needed to determine the protective capacity at home. Humans and also to discover correlates of protection and to determine whether identical or different immune correlates apply to different vaccine regimens.New vaccine concepts and vectors are under development and may evolve into trials. of effectiveness, which is an important process since the development of an AIDS vaccine remains urgent.Treatment and prophylaxis, the number of people living with HIV continues to increase around the world A moderately effective HIV vaccine and existing HIV prevention and treatment strategies should greatly contribute to the evolution of the HIV response It is therefore essential that a commitment to pursue multiple strategies for vaccine development continues at all stages.
This study was funded by Janssen Vaccines & Prevention BV, US National Institutes of Health, Ragon Institute of MGH, MIT and Harvard, Henry M Jackson Foundation for the Advancement of Military Medicine, US Department of Defense , and International AIDS Vaccine Initiative
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