- An experimental HIV vaccine being developed by Johnson & Johnson and the U.S. National Institutes of Health wasn’t effective at preventing infection in a large study, independent trial monitors determined after reviewing initial results.
- The trial will be discontinued as a result, J&J and the NIH said in Wednesday statements, although further data analyses are planned. No safety issues were identified with the vaccine regimen, which used a “mosaic” design that researchers had hoped could give broad protection against a variety of HIV strains.
- The trial enrolled just under 4,000 men who have sex with men and transgender people across eight countries in South and North America as well as Europe. A similar vaccine regimen was previously found to be insufficiently protective in a 2021 study of 2,600 women in sub-Saharan Africa.
Vaccine researchers have made remarkable advances in recent years, developing effective shots against new pathogens like SARS-CoV-2 as well as others that have evaded scientists for years like respiratory syncytial virus and Ebola.
Those successes were preceded by behind-the-scenes laboratory work that laid out better approaches for vaccine design, enabling the historically quick development of several COVID-19 shots and the clinical breakthroughs that have several companies on the cusp of a marketed RSV vaccine.
Designing a safe and effective HIV vaccine, though, has proved an intractable problem, with J&J and the NIH’s announcement Wednesday the latest setback.
J&J’s vaccine was based on what’s known as “mosaic” immunogens, essentially an amalgamation of virus elements from several HIV strains that are meant to spur broadly protective immune responses. In this case, the shot featured components from four virus subtypes, delivered via a common cold virus called adenovirus serotype 26. (The adenovirus chassis is similar to the one J&J used for its COVID-19 vaccine.)
The study regimen consisted of four shots over a year, with the second two accompanied by a mix of soluble HIV envelope proteins that were augmented with an adjuvant to boost immune responses. Enrollment in the trial, dubbed Mosaico, began in 2019 and all 3,900 participants had completed their vaccinations by October of last year.
However, a recent review by the study’s independent data and safety monitoring board concluded the regimen wasn’t effective at preventing HIV infection compared to a placebo. The review was based on available data which indicated the vaccine would not meet the study’s main goal, J&J said.
“We are disappointed with this outcome and stand in solidarity with the people and communities vulnerable to and affected by HIV,” said Penny Heaton, head of vaccines at J&J’s Janssen unit, in the company’s statement. “We remain steadfast in our commitment to advancing innovation in HIV, and we hope the data from Mosaico will provide insights for future efforts to develop a safe and effective vaccine.”
J&J worked with the NIH’s National Institute of Allergy and Infectious Diseases, as well as the HIV Vaccine Trials Network and the U.S. Army Medical Research & Development Command.