Findings from an early Phase I/IIa primate and human trial of the so-called mosaic HIV vaccine showed encouraging signs of the vaccine’s ability to prompt an immune response to the virus and backed the ongoing human efficacy trial of the vaccine currently running in sub-Saharan Africa, MedPage Today reports.

Preliminary findings from the APPROACH trial in 393 humans were presented a year ago at the 9th International AIDS Society Conference on HIV Science in Paris (IAS 2017). Now researchers have published in The Lancet complete findings from that trial as well as the NHP 13-19 study of 72 rhesus monkeys.

The best immune response among the human subjects occurred among those who received at least one dose ofthe mosaic adenovirus serotype 26 (Ad26) as well as a high dose of the gp140 boost vaccine. All members of this group had an antibody-based response to HIV 52 weeks later while 83 percent experienced a CD4 cell­–based response after 50 weeks.

The vaccine was safe and well tolerated. The most common adverse health event was pain at the injection site.

The monkey study gave one of five vaccine regimens or a placebo to the animals in order to settle on a preferred regimen for the advanced human trials. This regimen produced a similar immune response in humans. The researchers also tested the vaccine regimens’ efficacy among the primates and found that the preferred regimen reduced the risk of contracting SHIV, a simian version of HIV, by 67 percent.

Researchers have launched the Phase IIb efficacy study, called Imbokodo, of the vaccine regimen in five African nations among a planned 2,600 nonpregnant HIV-negative women. The trial is expected to complete in early 2022.

To read the MedPage Today article, click here.

To read the study abstract, click here.

To read a press release about the study, click here.