Upon joining the study, participants are required to be living with HIV, aged between 18 and 70 years, in good health, and on antiretroviral therapy (ART) for at least 12 months prior to screening. The current ART regimen must have been stable for at least 8 weeks before screening.

Participants must have a negative HIV-2 antibody test at screening, plasma HIV-1 RNA levels below the lower limit of quantification at screening and for at least 12 months prior, and a CD4+ T cell count of 500 cells/μL or higher at screening.

Participants will receive either budigalimab, ABBV-382, or a placebo. Budigalimab is a humanized monoclonal antibody administered either intravenously (IV) or subcutaneously (SC). ABBV-382 is also administered as a solution for injection or infusion.

The specific dosage, frequency, and duration of administration will be determined by the study protocol and communicated to participants during the trial.

Participants will undergo an analytical treatment interruption, during which their regular ART will be paused. The objective is to evaluate the efficacy, safety, and tolerability of the study medications in maintaining viral control without ART.

Participants will be monitored for viral control, defined as maintaining a viral load of less than 1000 copies/mL at Week 24 without restarting ART.

Secondary evaluations include measuring the peak viral load at rebound before restarting ART and the time to first rebound to 1000 copies/mL or more during the ART interruption.

The study is estimated to conclude by December 31, 2026. Participants will be informed of their results and any necessary follow-up actions at the end of the study.