Companies have halted an advanced trial of an HIV vaccine because the shot was found to not prevent infection.
Results from the stage 3 trial led to the determination that the vaccine “was not effective in preventing HIV infection compared to placebo among study participants,” Johnson & Johnson and its partners said in a statement.
The vaccine, dubbed Mosaico, was developed by Janssen, a Johnson & Johnson subsidiary.
The study’s Data and Safety Monitoring Board, or a group of independent experts that was monitoring the research, made the determination.
The study is being discontinued because of the determination, Johnson & Johnson said.
“We are disappointed with this outcome and stand in solidarity with the people and communities vulnerable to and affected by HIV,” Dr. Penny Heaton, an executive at Janssen, said in a 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,” Heaton added.
The U.S. National Institutes of Health, which provided funding for the study, said that the results would be further analyzed.
“In its scheduled data review, the [monitoring board] determined there were no safety issues with the experimental vaccine regimen. However, the number of HIV infections [was] equivalent between the vaccine and placebo arms of the study,” the agency said in a statement.
The study involved 3,900 people aged 18 to 60 in Europe and the Americas.
When launched, Dr. Susan Buchbinder, a University of California, San Francisco professor who helped lead the trial, said it was “an important step toward developing a safe and effective HIV vaccine for people worldwide.”
Buchbinder said this week that the results were disappointing.
“Although HIV continues to prove uniquely challenging for [the] development of a vaccine, the HIV research community remains fully committed to doing just that, and each study brings us a step closer to this realization,” she added.
HIV, or human immunodeficiency virus, attacks a person’s immune system and can lead to AIDS, or acquired immunodeficiency syndrome, if not treated. The illness is primarily contracted by men who have sex with other men. There is no known cure but treatment, in the form of pills and shots, can prevent progression to AIDS.
As of 2019, approximately 1.2 million people aged 13 and older had HIV in the United States, according to U.S. Centers for Disease Control and Prevention estimates. Thousands of people die each year with the disease. According to the World Health Organization, of an estimated 84 million people worldwide who were infected with HIV as of 2021, 47 percent have died from the illness.
After phase 2 testing in women, a different Janssen vaccine trial ended in 2021 after a monitoring board found it did not provide adequate protection against infection.
The results showed that 63 people who received a placebo were infected and 51 who received the shot were infected. The efficacy was just 25.2 percent.
Vaccine Technology
The adenovirus-based vaccines were built on so-called mosaic immunogens, or multiple HIV subtypes. Investigators hoped they would induce immune responses that resulted in protection against infection. Trial participants who received the Janssen vaccine also received a bivalent shot that contained aluminum phosphate.Preclinical studies had shown the Janssen vaccines protected monkeys against infection with an HIV-like virus, which led to human trials.
Results from an earlier trial testing a combination of vaccines from Sanofi Pasteur and the Global Solutions for Infectious Diseases found 31 percent efficacy. Vaccines aimed at improving efficacy have not done so, including the Johnson & Johnson shots. A trial testing a Sanofi Pasteur vaccine with a vaccine from GlaxoSmithKline showed the vaccines did not prevent infection, the companies announced in 2020.
Multiple other HIV vaccines based on messenger RNA (mRNA) technology are still being evaluated in trials. A U.S.-government-backed trial for three such vaccines was launched in early 2022, with results expected later this year.
Several COVID-19 vaccines are built with mRNA but have proved increasingly ineffective against infection, the purpose for which they’re authorized or approved. Real-world data suggest the vaccines help against severe illness, but that protection has also waned after the emergence of Omicron and its subvariants in late 2021.
“Finding an HIV vaccine has proven to be a daunting scientific challenge,” Dr. Anthony Fauci, the director of the National Institute of Allergy and Infectious Diseases until recently, said in a statement when the mRNA HIV vaccine trial was started. “With the success of safe and highly effective COVID-19 vaccines, we have an exciting opportunity to learn whether mRNA technology can achieve similar results against HIV infection.”
