Safety and Immunogenicity of Stabilized CH505 TF chTrimer Vaccination in Adults Living With HIV-1 on Suppressive Antiretroviral Therapy

Inclusion Criteria: * HIV-1 infection * On a suppressive ART regimen for at least 24 months with no changes in the 90 days prior to study entry * CD4+ cell count greater than 200 cells/mm3 obtained within 56 days prior to study entry * HIV-1 RNA \<200 copies/mL obtained within 56 days prior to study entry * Plasma HIV-1 RNA levels \<200 copies/mL for at least 12 months on ART prior to study entry * The following laboratory values obtained within 56 days prior to study entry * White blood cell count ≥2,500 cells/mm3 * Absolute neutrophil count (ANC) \>750/mm3 * Hemoglobin ≥11 g/dL for cisgender men/transgender women and ≥10 g/dL for cisgender women/transgender men * Platelet count ≥100,000/mm3 * Creatinine \<1.5x upper limit of normal (ULN) * Alanine aminotransferase (ALT) (SGPT) ≤1.5 ULN * Hepatitis C Virus (HCV) antibody-negative or HCV RNA negative result if indicated, within 56 days prior to study entry * Negative hepatitis B surface antigen (HBsAg) result obtained within 56 days prior to study entry * For study candidates of child-bearing potential, negative serum or urine pregnancy test at screening and within 48 hours prior to study entry * No participation in conception process and agree to use at least one reliable form of contraception if participating in sexual activity that could lead to pregnancy during the study and for 8 weeks following the final study vaccine Exclusion Criteria: * Known to have started ART during acute HIV infection * Known to have HIV-related opportunistic infections within the last 2 years prior to study entry. * History of malignancy within the last 5 years prior to study entry. * Currently breastfeeding * History of or active autoimmune disorders * HIV vaccination (prophylactic and/or therapeutic) within 1 year prior to study entry * Receipt of any anti-HIV-1 bNAbs within 2 years prior to study entry * Vaccination within 4 weeks prior to study entry * Use of any infusion blood product or immune globulin within 16 weeks prior to study entry (Exception: COVID-19-specific monoclonal antibodies are allowed) * Use of systemic immunomodulators, systemic cytotoxic chemotherapy, or non-FDA approved investigational therapy within 60 days prior to study entry * Intent to use immunomodulators during the course of the study * Immune deficiency other than HIV * HCV antiviral therapy within 90 days prior to screening * Known allergy/sensitivity or any hypersensitivity to components of study drug(s) or their formulation * Active drug or alcohol use or dependence that would interfere with adherence to study requirements * Acute or serious illness requiring systemic treatment and/or hospitalization within 30 days prior to study entry * Conditions that would preclude injection site reaction assessments (e.g., extensive tattoos, scarring, skin conditions).