Background: VRC 607/ACTG 5378 is a two-part study conducted by the VRC and ACTG investigating the CD4 binding site HIV-1 broadly neutralizing antibodies (bNAbs) VRC01LS (Part A) and VRC07-523LS (Part B) in treatment naïve HIV-infected adults. The study objectives were to evaluate safety and tolerability (primary) and antiviral activity and pharmacokinetic (PK) parameters (secondary).
Methods: 16 HIV-infected viremic adults between the ages of 18-70 were enrolled. Seven participants in Part A received one intravenous (IV) dose of 40 mg/kg VRC01LS, and nine participants in Part B received one IV dose of 40 mg/kg VRC07-523LS. Safety was evaluated by collection of local and systemic reactogenicity symptoms for three days and adverse events (AEs) for 56 days post product administration. Blood samples were collected at pre-specified study timepoints for viral load and PK analysis as well as CD4/8 T-cell counts and safety labs. The study is ongoing at the time of this report.
Results: In Part A, VRC01LS was safe and well tolerated. No local reactogenicity was reported and systemic reactions (n=1) were mild. There were no AEs related to the study product. Seven days post-infusion, 3/7 participants had at least a 0.5 log10 decrease in viral load (Fig. 1A). In Part B, VRC07-523LS was safe and well tolerated. Local (n=3) and systemic (n=2) reactogenicity were mild. Two AEs were assessed as related to the study product; infusion site paraesthesia and decreased neutrophil count, both which resolved with no residual effects the day of infusion and 8 days following onset, respectively. Seven days post-infusion, 8/9 participants had at least 1.2 log10 decrease in viral load (Fig. 1B).
Conclusions: Both VRC01LS and VRC07-523LS were safe and well-tolerated when administered to viremic HIV-infected adults. Antiviral activity > 0.5 log was observed in 3/7 VRC01LS recipients and >1.2 log for 8/9 VRC07-523LS recipients.

Post antibody administration viral load
[Post antibody administration viral load]