Another HIV Vaccine Trial Fails After Large-Scale Study

The only HIV vaccine being tested and nearing completion of trial trials has been found to be ineffective, its manufacturer has announced.

Known as Mosaic, the trial was the product of a public-private partnership that included the US government and Janssen Pharmaceuticals.

HIV is a virus that gradually attacks the immune system, which is our body’s natural defense against disease. AIDS is a syndrome caused by the HIV virus.

The failure of the latest candidate underscores the challenges of designing an HIV vaccine.

The announcement posted on the Johnson & Johnson website noted that the study’s independent Data and Safety Monitoring Board determined that the regimen was not effective in preventing HIV infection compared with placebo among study participants.

He also said that no safety issues with the vaccine regimen were identified.

In light of the DSMB determination, the Mosaico clinical trial will be discontinued, he said.

He noted that notifications to participants and further analysis of the data are underway. Throughout the trial, the study investigators made sure that all people who contracted HIV received HIV care and treatment without delay.

“We are disappointed with this result and stand in solidarity with individuals and communities vulnerable to and affected by HIV,” said Penny Heaton, director of global vaccine therapeutics at Janssen Research & Development, LLC.

“Although there have been significant advances in prevention since the start of the global epidemic, 1.5 million people contracted HIV in 2021 alone, underscoring the great unmet need for new options and why we have long worked to address this global health challenge.

“We remain steadfast in our commitment to promote innovation in HIV and hope that the Mosaico data will inform future efforts to develop a safe and effective vaccine. We are grateful to our Mosaico partners and the study researchers, staff and participants.”

Remember that in 2020, the US National Institutes of Health announced the end of its HVTN 702 clinical trial of an HIV vaccine. While no safety concerns were found during the trial, the independent data and safety monitoring board found that the vaccine was not effective in preventing HIV transmission.

In addition, in 2021, an experimental HIV vaccine tested in the “Imbokodo” clinical trial in sub-Saharan Africa posed no safety concerns but did not provide sufficient protection against HIV infection, according to a primary analysis of data from the study.

Meanwhile, Mosaic, a phase three study of Janssen’s investigational HIV vaccine regimen, began in 2019 and completed vaccinations in October 2022.

The study included approximately 3,900 cisgender men and transgender people who have sex with cisgender men and/or transgender people, representing groups and populations vulnerable to HIV, at more than 50 test sites in Argentina, Brazil, Italy, Mexico, Peru , Poland, Puerto Rico, Spain and the United States.

“The study evaluated an investigational vaccine regimen containing a mosaic-based adenovirus serotype 26 vector (Ad26.Mos4.HIV) administered during four vaccination visits over one year. A soluble protein mixture (Clade C/Mosaic gp140, adjuvanted with aluminum phosphate) was also administered at visits three and four.

“The DSMB Mosaic analysis, based on the data available to date, indicated that the regimen does not protect against HIV and the study is not expected to meet its primary endpoint. No safety concerns with the vaccine regimen were identified. In light of this, the study will be discontinued and further analysis is ongoing.

“The DSMB determination follows the primary analysis of the Phase 2b Imbokodo study, which was announced in August 2021 and found that a similar investigational HIV vaccine regimen did not provide sufficient protection against HIV in a population of young women in Sub-Saharan Africa.

“The investigational vaccine regimen used in the Imbokodo study was found to have a favorable safety profile,” he added.

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