Safety, pharmacokinetics, and neutralisation activity of PGDM1400LS, a V2 specific HIV-1 broadly neutralising antibody, infused intravenously or subcutaneously in people without HIV-1 in the USA (HVTN 140/HPTN 101 part A): a first-in-human, phase 1 randomised trial.

Abstract

Background: PGDM1400LS is a human monoclonal antibody targeting the HIV envelope V2 apex with a lysine-serine modification intended to enhance serum and tissue half-lives and is being considered for use in combination monoclonal antibody trials. We sought to test whether PGDM1400LS was safe and had favourable serum concentration, pharmacokinetics, and neutralising ability in healthy adults.

Methods: HVTN 140/HPTN 101 part A is an open-label, dose escalation, first-in-human phase 1 trial of PGDM1400LS given intravenously or subcutaneously to healthy adults aged 18-50 years without HIV-1. The study enrolled participants at four sites in the USA, across five groups, each receiving one dose of PGDM1400-LS intravenously (group 1: 5 mg/kg; group 2: 20 mg/kg; and group 4: 40 mg/kg) or subcutaneously (group 3: 20 mg/kg; and group 5: 40 mg/kg). Participants in group 1 were enrolled sequentially without random assignment. Participants in groups 2 and 3 were block randomised and enrolled simultaneously after group 1 safety review. Groups 4 and 5 followed the same process, contingent on groups 2 and 3 safety review. The primary endpoints were safety and tolerability of PGDM1400LS, serum concentration of PGDM1400LS, and serum neutralising activity after single administration of PGDM1400LS. Serum PGDM1400LS concentrations collected at seven timepoints (day 0, day 3, day 6, day 28, day 56, day 112, and day 168) were assessed via an anti-idiotype binding assay and characterised via non-compartmental pharmacokinetic analysis. Serum neutralisation activity (ID₈₀) was assessed by a TZM-bl assay. The study is registered with ClinicalTrials.gov, NCT05184452.

Findings: Between Nov 15, 2021, and March 4, 2022, 15 participants were enrolled into the five study groups (three participants per group) with 6 months of follow-up. Ten of 15 participants were female, 14 of 15 participants were non-Hispanic, and 11 of 15 participants were White, with a median age of 27 years (range 24-47). PGDM1400LS was safe and well tolerated, with mild to moderate solicited symptoms. Serum concentrations showed dose proportionality by administration route, with peak concentrations observed immediately after intravenous infusion (range 95·7-727·4 μg/mL) or on day 6 after subcutaneous infusion (205·6-547·1 μg/mL). The median elimination half-life was 55 days (range 48-59), representing a 2-to-3-times increase versus parental PDGM1400. Estimated subcutaneous (vs intravenous) bioavailability was 50-60%. ID₈₀ titres showed agreement with concentration-predicted ID₈₀ titres, indicating maintenance of neutralisation activity in vivo.

Interpretation: PGDM1400LS is a promising candidate for combination monoclonal antibody efficacy trials going forward.

Funding: National Institute of Allergy and Infectious Diseases-National Institutes of Health.