The HIV vaccine candidate was developed using the same AdVac viral vector platform as the company’s COVID-19 vaccine.
The Imbokodo study was run among young women in sub-Saharan Africa at high risk of acquiring HIV. The investigational adenovirus vector vaccine vaccine was found to have a favorable safety profile with no serious adverse events; but did not meet its primary endpoint with a vaccine efficacy of only 25.2%.
The study was run by Janssen and funded by the Bill & Melinda Gates Foundation (BMGF) and the National Institute of Allergy and Infectious Diseases (NIAID), part of the National Institutes of Health.
“The development of a safe and effective vaccine to prevent HIV infection has proven to be a formidable scientific challenge,” said NIAID Director Anthony S. Fauci, M.D. “Although this is certainly not the study outcome for which we had hoped, we must apply the knowledge learned from the Imbokodo trial and continue our efforts to find a vaccine that will be protective against HIV.”
Quadrivalent vaccine
The vaccine in the Imbokodo study is based on “mosaic” immunogens—vaccine components designed to induce immune responses against a wide variety of global HIV strains. The vaccine candidate uses a strain of common-cold virus (adenovirus serotype 26, or Ad26) to deliver four mosaic antigens to spur an immune response.
Imbokodo, a Phase 2b proof-of-concept efficacy study of the vaccine, began in 2017, reached full enrollment in 2019 and completed vaccinations on June 30, 2020. The study enrolled approximately 2,600 young women across five countries in sub-Saharan Africa, a region where women and girls accounted for 63% of all new HIV infections in 2020. The study took place at 23 trial sites in Malawi, Mozambique, South Africa, Zambia and Zimbabwe.