Pharmacokinetics and safety of XAV-19, a swine glyco-humanized polyclonal anti-SARS-CoV-2 antibody, for COVID-19-related moderate pneumonia: a randomized, double-blind, placebo-controlled, phase IIa study

Gaborit, B.; Dailly, E.; Vanhove, B.; Josien, R.; Lacombe, K.; Dubee, V.; Ferre, V.; Brouard, S.; Ader, F.; Vibet, M.-A.; Le Thuaut, A.; Danger, R.; Omnes, A. O.; Berly, L.; Chiffoleau, A.; Jobert, A.; Duvaux, O.; Raffi, F.

Background: We assessed the pharmacokinetics and safety of XAV-19, a swine glyco-humanized polyclonal antibody against SARS-CoV-2, in COVID-19-related moderate pneumonia. In vitro, 100% neutralization activity is seen with XAV-19 concentrations above 5 microg/mL. Methods: In this phase 2a trial, adults with COVID-19-related moderate pneumonia of [≤]10 days duration were randomized to infusion of XAV-19 0.5 mg/kg at day 1 and day 5 (group 1), 2 mg/kg at day 1 and day 5 (group 2), 2 mg/kg at day 1 (group 3) or placebo. Results: Eighteen patients (n=7 for group 1, n=1 for group 2, n=5 for group 3, and n=5 for placebo) were enrolled. Baseline characteristics were similar across groups, XAV-19 serum concentrations (microg/mL, median, range) at Cmax and at day 8 were 9.1 (5.2-18.1) and 6.4 (2.8-11.9), 71.5 and 47.2, and 50.4 (29.1-55.0) and 20.3 (12.0-22.7) for groups 1, 2 and 3, respectively (p=0.012). Terminal half-life (median, range) was estimated at 11.4 (5.5-13.9) days for 2 mg/kg of XAV-19 at day 1. Serum XAV-19 concentrations were above the target concentration of 10 microg/mL (tow fold the in vitro 100% inhibitory concentration [IC100]) from the end of perfusion to more than 8 days for XAV-19 2 mg/kg at day 1. No hypersensitivity or infusion-related reactions were reported during treatment, there was no discontinuation for adverse events and no serious adverse events related to study drug. Conclusions: Single intravenous dose of 2 mg/kg of XAV-19 demonstrated high serum concentrations, predictive of potent durable neutralizing activity with good tolerability.