Janssen, Global Partners to discontinue Phase 3 Mosaico HIV vaccine trial

In light of the DSMB’s determination, the Mosaico clinical trial will be discontinued. Participant notifications and further analyses of the data are underway. Throughout the trial, study investigators have ensured that any individuals who contracted HIV received prompt HIV treatment and care.

“We are disappointed with this outcome and stand in solidarity with the people and communities vulnerable to and affected by HIV,” said Penny Heaton, M.D., Global Therapeutic Area Head, Vaccines, Janssen Research & Development, LLC. “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. 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. We are grateful to our Mosaico partners and the study investigators, staff and participants.”

Mosaico, a Phase 3 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, who represent groups and populations vulnerable to HIV, at over 50 trial 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 mix of soluble proteins (Clade C/Mosaic gp140, adjuvanted with aluminum phosphate) was also administered at visits three and four.

The Mosaico DSMB 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 issues with the vaccine regimen were identified. In light of this, the study will be discontinued, and further analyses are underway.

The DSMB’s 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.

The Mosaico study was led by a global public-private partnership including the National Institute of Allergy and Infectious Diseases (NIAID), part of the National Institutes of Health (NIH), the HIV Vaccine Trials Network (HVTN), the U.S. Army Medical Research and Development Command (USAMRDC), and Janssen Vaccines & Prevention B.V. Since 2005, Janssen Vaccines & Prevention B.V. has been participating as a sub-grantee in the NIH-supported Integrated Preclinical/Clinical AIDS Vaccine Development (IPCAVD) program under grants AI066305, AI078526, AI096040 and AI128751 (Principal Investigator, Prof. Dan Barouch).