J&J reports second HIV vaccine regimen failure in 18 months
After more than four decades, there is still no approved HIV vaccine. And another so-called mosaic regimen has ended in disappointment.
Johnson & Johnson’s Janssen unit said Wednesday that an independent data and safety monitoring team found the Big Pharma’s regimen to be ineffective at preventing HIV infection compared to placebo. The drug developer reported no safety issues.
With that, J&J ended the Phase III Mosaico study, which enrolled 3,900 cisgender men and transgender individuals in Argentina, Brazil, Italy, Mexico, Peru, Poland, Puerto Rico, Spain and the US. People in the trial who contracted the virus were given “prompt HIV treatment and care,” the company said.

“We are disappointed with this outcome and stand in solidarity with the people and communities vulnerable to and affected by HIV,” Janssen’s vaccines R&D leader, Penny Heaton, said in a statement. “Though there have been significant advances in prevention since the beginning of the global epidemic, 1.5 million people acquired HIV in 2021 alone, underscoring the high unmet need for new options and why we have long worked to tackle this global health challenge.”
Researchers gave participants a tetravalent vaccine known as Ad26.Mos4.HIV, using a common-cold virus, via an intramuscular injection on days 1, 3, 6 and 12, and a bivalent vaccine, which includes Adjuvanted Clade C gp140 and Mosaic gp140, at months six and 12, according to a clinicaltrials.gov study entry.
Janssen, other biopharmas and researchers have for decades tried to create an effective vaccine for HIV, but none have made it across the regulatory finish line. Multiple treatment options have been available for decades, as have preventative measures known as PrEP, but only a few vaccine attempts have come close to success.
As part of the study, clinic staffers asked community members if they were interested in PrEP. If they didn’t choose PrEP, they were considered for the trial, according to study coordinator the HIV Vaccine Trials Network, at Fred Hutch.
“We only enrolled participants not on PrEP after they had been given an authentic choice to go on PrEP, with barriers removed to accessing these drugs,” said study co-chair Susan Buchbinder, a University of California, San Francisco clinical professor, in a statement. “One thing we’ve clearly learned from study participants is that people want a choice, and that a vaccine will be an important option for those who don’t want PrEP.”
A different vaccine regimen from Janssen failed the Phase II Imbokodo study last year. That candidate used the same tech behind the pharma giant’s Covid-19 shot, which is largely on its way out from the US market.
At the time of the Imbokodo trial stoppage, the data and safety monitoring board recommended Mosaico continue because it was testing a slightly different regimen and was being investigated in a different patient population.
In early 2020, a regimen from Sanofi and GSK also missed the bar in a Phase IIb/III trial that enrolled 5,407 people in South Africa.
While the late-stage pipeline has now dwindled, other groups are in earlier phases of testing new vaccines, including Moderna, Vir Biotechnology, the National Institutes of Health and Gilead-allied Aelix Therapeutics.