Experimental vaccine has potential against a wide variety of HIV strains | Drug

An experimental "mosaic" vaccine against a wide variety of HIV strains is well tolerated and produces comparable and robust immune responses in healthy adults and Rhesus macaques, according to a new study published in The Lancet ].

Nearly 37 million People around the world are living with HIV / AIDS, with about 1.8 million new cases each year. A safe and effective preventive vaccine is urgently needed to stem the HIV pandemic.

During the three decades of the epidemic, only four vaccine concepts were tested in humans, and only one demonstrated its protection in an efficacy trial. a vector canarypox vaccine, gp120 boost vaccine tested in the RV144 trial in Thailand lowered the human infection rate by 31%, but the effect was deemed too low to advance the vaccine to a use common.

A Major Barrier to HIV Vaccine Development To address these issues, Professor Dan Barouch of the Beth Israel Deaconess Medical Center and Harvard Medical School and co-authors evaluated the main mosaic adenovirus serotype 26 (Ad26) – Candidate vaccines against HIV-1 in a randomized, double-blind, placebo-controlled Phase 1 / 2a trial (APPROACH).

The researchers included 393 healthy and uninfected HIV-1s (18- to 50-year-olds) participants considered to be at low risk for HIV-1 infection.

Volunteers were recruited from 12 clinics in East Africa, South Africa, Thailand and the United States. They were randomly badigned to receive one of seven vaccine combinations or a placebo, and received four vaccinations within 48 weeks.

To stimulate, or "prime", an initial immune response, each volunteer received an intramuscular injection The vaccine containing the HIV Env / Gag / Pol "mosaic" antigens was created from numerous HIV strains, administered with the aid of a non-replicating common cold virus (ibidem). Ad26).

To "boost" the level of the body's immune response, volunteers received two additional vaccines at weeks 24 and 48 using various combinations of Ad26.Mos.HIV or a different vaccine component called Vaccinia Modified Ankara with or without two different doses of clade C HIV gp140 protein envelope containing an adjuvant of 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, most of which were of mild to moderate severity.

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, scientists 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. – The candidate vaccine Ad26 / Ad26 plus gp140 induces the greatest immune responses in humans and also offers the best protection in monkeys, which translates into complete protection against infection with the virus. Simian human immunodeficiency in two humans. – Three-thirds of vaccinated animals after six challenges

"Our results represent a milestone," said Professor Barouch.

"This study demonstrates that ad26 prime mosaic, Ad26 plus gp140 boost the HIV vaccine, in humans and monkeys of a magnitude, kinetics, phenotype and comparable durability, and also provided 67% protection against "

" These results should be interpreted with caution, "he added.

" Challenges in the development of a HIV vaccine is unprecedented, and the ability to induce specific immune responses to HIV does not necessarily indicate "We are looking forward to the results of the Phase 2b efficacy test called HVTN705, who will determine whether or not this vaccine will protect humans from HIV infection. " _____

Dan H. Barouch and others . Evaluation of an HIV-1 mosaic vaccine in a multicenter, randomized, double-blind clinical trial ble, placebo-controlled, phase 1 / 2a (APPROACH) and rhesus monkeys (NHP 13-19). The Lancet published online July 6, 2018; doi: 10.1016 / S0140-6736 (18) 31364-3