Evaluating the Safety, Tolerability, Pharmacokinetics, and Antiviral Activity of the Monoclonal Antibody PGT121.414.LS Administered Alone and in Combination With VRC07-523LS Via Intravenous or Subcutaneous Infusions in Healthy, HIV-uninfected Adult Participants

The purpose of this study is to evaluate the safety, tolerability, pharmacokinetics, and antiviral activity of the monoclonal antibody PGT121.414.LS administered alone and in combination with VRC07-523LS via intravenous or subcutaneous infusions in healthy, HIV-uninfected adult participants.

This study will evaluate the safety, tolerability, pharmacokinetics, and antiviral activity of the monoclonal antibody PGT121.414.LS administered alone and in combination with VRC07-523LS via intravenous (IV) or subcutaneous (SC) infusions in healthy, HIV-uninfected adult participants. The study will be conducted in two parts (Part A and B). Part A will include four groups (Groups 1, 2, 3, and 4) and Part B will include two groups (Groups 5 and 6). In Part A of the study, PGT121.414.LS will be administered via IV infusion at 3, 10, or 30 mg/kg (Groups 1-3) or via SC infusion at 5 mg/kg (Group 4). Participants in Part B will receive consecutive administration of PGT121.414.LS followed by VRC07-523LS, at 20 mg/kg IV each per dose (Group 5) or 5 mg/kg SC each per dose (Group 6). Participants will be followed for 32 weeks after the last study product administration via IV infusion and 24 weeks after the last study product administration via SC infusion. Participants in Groups 1, 2, and 3 will attend 8 months of study visits. Participants in Group 4 will attend 6 months of study visits. Part B participants will attend 16 months of study visits. Study visits may include physical examinations, blood and urine collection, and questionnaires.