Experimental HIV vaccine does not protect women
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Johnson & Johnson’s investigational HIV vaccine did not provide sufficient protection against HIV infection among women enrolled in the phase 2b Imbokodo trial in sub-Saharan Africa, the company and the NIH said Tuesday.
The Imbokodo trial, a phase 2b proof-of-concept study, launched in 2017. It compared the number of new HIV infections that occurred among participants who received the vaccine with the number of infections in a placebo group.
The study enrolled 2,637 women aged 18 to 35 years from five countries Malawi, Mozambique, South Africa, Zambia and Zimbabwe. The women in the treatment arm received four vaccinations during a 1-year period and were followed for at least 2 years. Researchers conducted the primary analysis 24 months after participants received their first vaccinations.
Overall, 63 of 1,109 participants in the placebo arm and 51 of 1,079 participants in the vaccine arm acquired HIV, yielding an estimated vaccine efficacy of 25.2% (95% CI, –10.5% to 49.3%). Additionally, the vaccine was found to be safe with no serious adverse events associated with it.
As of January, Imbokodo was one of just three ongoing HIV vaccine efficacy trials after the National Institute of Allergy and Infectious Diseases (NIAID) last year cancelled a phase 2b/3 trial of an investigational vaccine that was based on the only vaccine regimen ever to demonstrate protection against HIV.
“The development of a safe and effective vaccine to prevent HIV infection has proven to be a formidable scientific challenge,” NIAID director Anthony S. Fauci, MD said in a statement. “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.”
According to the NIH, further analysis of the Imbokodo study will continue because the study is “thought to have provided sufficient data for further immunological correlates research.” Additionally, consultants on the Imbokodo trial have also determined that the Mosaico trial a complementary phase 3 vaccine study evaluating another investigational vaccine that uses “mosaic” immunogens to provide maximum coverage against circulating HIV strains should continue.
The NIH said the Mosaico trial is investigating the second vaccine in different patient populations, including men who have sex with men and transgender populations in the Americas and Europe. The trial is estimated to be completed in March of 2024.
References:
NIH. HIV vaccine candidate does not sufficiently protect women against HIV infection. https://www.nih.gov/news-events/news-releases/hiv-vaccine-candidate-does-not-sufficiently-protect-women-against-hiv-infection. Accessed August 31, 2021.
NIH. NIH and partners to launch HIV vaccine efficacy trial in the Americas and Europe. https://www.niaid.nih.gov/news-events/nih-and-partners-launch-hiv-vaccine-efficacy-trial-americas-and-europe. Accessed August 31, 2021.
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