Study of a Human Bispecific Antibody VRC-HIVMAB0121-00-AB (CAP256J3LS) Administered Intravenously or Subcutaneously to Healthy Adults

Design: This first-in-human, Phase 1, open-label study will examine safety, tolerability, dose, and pharmacokinetics (PK) of CAP256J3LS (VRC-HIVMAB0121-00-AB) in healthy adults in a dose-escalation design. The primary hypothesis is that subcutaneous (SC) and intravenous (IV) administrations of CAP256J3LS will be safe and well-tolerated in healthy adults. A secondary hypothesis is that CAP256J3LS will be detectable in human sera with a definable half-life. Study Products: The CAP256J3LS bispecific antibody (bsAb) targets the V2-apex and CD4-binding sites of the HIV-1 envelope. It is composed of the J3 camelid nanobody linked to CAP256V2LS through a 15 amino acid linker arm attached to the N-terminus of the CAP256V2LS light chain. The addition of the J3 nanobody adds a CD4-binding site directed neutralization functionality to the CAP256V2LS, which targets the V2 region of the HIV Env trimer. The bispecific antibody was developed by the VRC/NIAID/NIH and is manufactured under cGMP regulations at the VRC Pilot Plant operated under contract by the Vaccine Clinical Materials Program (VCMP), Leidos Biomedical Research, Inc., Frederick. MD. Participants: Healthy adults, 18-60 years of age Study Plan: This open-label study will include 6 groups to evaluate CAP256J3LS administered one time or by repeat dosing. Enrollment will begin with the 5 mg/kg dose groups, and enrollment for subsequent dose groups will proceed after dose-escalation safety reviews. Assessment of safety will include solicited reactogenicity and other adverse events, clinical observations, and monitoring of hematological and chemistry parameters at clinical visits throughout the study.