Johnson & Johnson has already advanced a "mosaic" HIV vaccine candidate into efficacy testing in five southern African countries, but this week the company unveiled initial results from an early-stage study comparing tetravalent and trivalent candidates in its program.

In the study, dubbed Traverse, the tetravalent version—which targets four strains of the virus—broadened the immune responses to different HIV-1 strains compared to the three-strain, trivalent version, J&J reports. The company has already moved the tetravalent candidate into efficacy testing and is expecting its first results in 2021. 

In a previous study called Approach, J&J reported that a trivalent vaccine demonstrated a favorable safety and immunogenicity profile. Then, this summer, J&J touted results showing that responses from the vaccine lasted at least one year.  

The company presented its latest results at the HIV Research for Prevention Conference in Madrid. At the conference, Daniel Stieh, senior HIV biomarker lead for Janssen, told an audience the Traverse findings were "critical" in the decision by J&J and its partners to start the efficacy test. He said that both the tetravalent and trivalent vaccines showed a favorable safety profile and elicited immune responses in all of the study participants.  

But the "breadth and functionality of the antibody response, as well as the cellular immune response, is enhanced" in the newer version, he added. 

J&J is conducting the Traverse study in about 200 patients in the U.S. and Rwanda. For the study, investigators gave participants two prime doses of either shot at weeks 0 and 12, followed by boosters at weeks 24 and 48. The company presented its analysis from week 28, or after the first boost. 

The drugmaker is among a group of industry players and global nonprofits working to advance HIV vaccine prospects; it's working to create a "mosaic" vaccine that could be used all around the world. Other HIV vaccine programs have aimed at protecting against the virus region by region, limiting their use, collaborator Dan Barouch, M.D., Ph.D., of Harvard's Beth Israel Deaconess Medical Center previously told FiercePharma.

Meanwhile, another large HIV vaccine efficacy test is underway in South Africa. That study is testing a HIV vaccine regimen featuring components from GlaxoSmithKline and Sanofi, with support from the U.S. National Institutes of Health and others.