An open‐label, single‐dose bioavailability study of the pharmacokinetics of CAT‐354 after subcutaneous and intravenous administration in healthy males

WHAT IS ALREADY KNOWN ABOUT THIS SUBJECT • The safety profile and effective dose of CAT‐354 have been determined with intravenous (i.v.) administration, but no information is available on subcutaneous (s.c.) administration. WHAT THIS STUDY ADDS • This study characterized the pharmacokinetics of CAT‐354 following s.c. administration of 150 mg and 300 mg doses, and indicated a bioavailability of approximately 60%. AIM To assess the bioavailability and pharmacokinetics of CAT‐354, an anti‐IL‐13 human monoclonal IgG4 antibody, following subcutaneous (s.c.) and intravenous (i.v.) administration. METHODS This was a single‐dose, randomized, open‐label, parallel‐group bioavailability study. Healthy male subjects aged 20–54 years were randomly assigned to one of three dose groups ( n = 10/group) to receive CAT‐354: 150 mg i.v.; 150 mg s.c. or 300 mg s.c. (two 150 mg injections). Serum pharmacokinetics, adverse events (AEs), vital signs, electrocardiograms and laboratory parameters were assessed. RESULTS CAT‐354 showed bioavailability of 62% and 60% after 150 mg and 300 mg s.c. doses, respectively, and linear pharmacokinetics over the dose range tested. Peak serum concentrations in the s.c. groups occurred after 3–9 (median 5) days, with a mean elimination half‐life of 19.2 ± 3.1 days (150 mg) and 19.4 ± 3.59 days (300 mg) after s.c. and 21.4 ± 2.46 days after i.v. administration. Volume of distribution at steady state ( V ss ) was 4960 ± 1440 ml kg −1 after i.v. (slightly greater than plasma volume). Average apparent clearances (CL/ F ) were 292 ± 82.3 and 307 ± 109 ml day −1 after 150 and 300 mg s.c., respectively; systemic CL of 188 ± 84.0 ml day −1 after i.v. dosing was consistent with endogenous IgG and reticuloendothelial elimination. No severe or serious AEs occurred. Among 40 reported AEs, 25 were headache, sinus disorders/respiratory symptoms and changes in body temperature perception. CONCLUSIONS CAT‐354 exhibited bioavailability of approximately 60% when given s.c. to healthy male subjects.