An investigational HIV vaccine regimen tested among men who have sex with men (MSM) and transgender people was safe but did not provide protection against HIV acquisition, an independent data and safety monitoring board (DSMB) has determined. The HPX3002/HVTN 706, or ‘Mosaico,’ Phase 3 clinical trial began in 2019 and involved 3,900 volunteers ages 18 to 60 years in Europe, North America and South America. Based on the DSMB’s recommendation, the study will be discontinued.