HIV Vaccine Study Discontinued at Phase 3 Due to Inadequate Results

In a recent press release, the HIV Vaccine Trials Network (HVTN) announced that the Mosaico study, an investigational HIV vaccine study, was discontinued at phase 3 after an interim review by the Data and Safety Monitoring Board (DSMB) of the investigation. According to the press release, the data review found inadequate and disappointing results.

This study, also known as HPX3002/HVTN706, began in October 2019 and was supposed to continue until March 2024. It was a clinical trial that recruited cis-gendered men and transgender people between 18 and 64 who have sex with cis-gendered men and transgender people. The study had sites in North America, Latin America, and Europe, with a home base at the Fred Hutchinson Cancer Center in Seattle, Washington. Overall, the study enrolled 3,900 individuals across more than 50 trial sites.

This vaccine trial was part of a more considerable community effort to prevent HIV. The vaccine itself was developed from the genetic material of multiple HIV strains in the hopes of triggering a broad immune response. At the review conducted by the DSMB, the team found that, while the drug was safe and tolerable, it did not effectively prevent HIV-1.

“HIV is a constantly changing and very challenging adversary. We can become disappointed when our best efforts don’t produce the results we’re looking for,” said Larry Corey, MD, principal investigator of HVTN’s Leadership and Operations Center, headquartered at the Fred Hutchinson Cancer Center, in the press release. “We have, however, come a long way and made many discoveries since the time when life expectancy was very short following an HIV diagnosis.”

Despite the disappointment at the results of this trial and the need to discontinue, Corey and other members of the HVTN are not disheartened. Instead, the experience of this study and its tactics, which recruited a diverse patient population, may help inform future studies.

Additionally, they note that this study is not the only ongoing study for HIV vaccines. Currently, Moderna has ongoing research for an mRNA HIV vaccine. Although there is some uncertainty surrounding the future of HIV prevention, researchers are putting forth their best efforts to enhance care and prevention strategies.