Preclinical development of AMG 139, a human antibody specifically targeting IL-23

Abstract

Background and purpose: AMG 139 is a human anti-IL-23 antibody currently in a phase II trial for treating Crohn's disease. To support its clinical development in humans, in vitro assays and in vivo studies were conducted in cynomolgus monkeys to determine the pharmacology, preclinical characteristics and safety of this monoclonal antibody.

Experimental approach: The in vitro pharmacology, pharmacokinetics (PK), pharmacodynamics and toxicology of AMG 139, after single or weekly i.v. or s.c. administration for up to 26 weeks, were evaluated in cynomolgus monkeys.

Key results: AMG 139 bound with high affinity to both human and cynomolgus monkey IL-23 and specifically neutralized the biological activity of IL-23 without binding or blocking IL-12. After a single dose, linear PK with s.c. bioavailability of 81% and mean half-life of 8.4-13 days were observed. After weekly s.c. dosing for 3 or 6 months, AMG 139 exposure increased approximately dose-proportionally from 30 to 300 mg·kg(-1) and mean accumulation between the first and last dose ranged from 2- to 3.5-fold. Peripheral blood immunophenotyping, T-cell-dependent antigen responses and bone formation markers were not different between AMG 139 and vehicle treatment. No adverse clinical signs, effects on body weight, vital signs, ophthalmic parameters, clinical pathology, ECG, organ weights or histopathology were observed in the monkeys with the highest dose of AMG 139 tested (300 mg·kg(-1) s.c. or i.v.).

Conclusions and implications: The in vitro pharmacology, PK, immunogenicity and safety characteristics of AMG 139 in cynomolgus monkeys support its continued clinical development for the treatment of various inflammatory diseases.

Figure 1

AMG 139 inhibits IL-23 activity in a COS cell reporter gene assay. COS-pool 12 cells (expressing huIL-12 receptors β1 subunit and huIL-23 receptors) were transiently transfected with a STAT1/4-luciferase reporter for 48 h. At the day of the experiment, COS-pool 12 cells were incubated with native human IL-23 (A), recombinant human IL-23 (B), recombinant cynomolgus monkey IL-23 (C) or recombinant rat IL-23 (D) in the presence of various concentrations of AMG 139. AMG 139 was pre-incubated with IL-23 for 20 min prior to addition to the cells. After 5 h, relative light units (RLU) were measured as an indicator of the STAT1/4-luciferase reporter using the Bright-Glo luciferase as described in the Methods section. Data are representative of n = 3 (A–C) or n = 2 (D) independent experiments. Values are expressed as mean ± SEM for duplicated measures.

Figure 2

AMG 139 inhibits IL-23 activity in NK cells. Human NK cells were incubated with native human IL-23 (A), recombinant human IL-23 (B), recombinant cynomolgus monkey IL-23 (C) or recombinant human IL-12 (D) in the presence of various concentrations of AMG 139 (A–D) or the positive control IL-12p35 antibody mAb219 (D). AMG 139 or mAb219 was incubated with IL-23 or 0.3 ng·mL⁻¹ IL-12, for 30 min prior to addition to the cells. After 24 h in culture, the supernatant was collected and IFN-γ was measured via elisa. Results are representative of at least three experiments, except (A) which is n = 2. Data are presented as mean ± SD.

Figure 3

AMG 139 inhibits IL-23 activity in human (A and B) and cynomolgus monkey (C) whole blood. Whole blood was incubated with recombinant human IL-23 (A) or recombinant cynomolgus monkey IL-23 (B and C) in the presence of various concentrations of AMG 139; AMG 139 was pre-incubated with IL-23 for 30 min prior to addition to the cells. After 24 h in culture, the supernatant was collected and IFN-γ was measured via elisa. Results are representative of experiments conducted in blood from four to eight donors; results are represented as mean ± SD.

Figure 4

Mean (±SD) serum concentration-time profiles of AMG 139. Cynomolgus monkeys were administered a single i.v. or s.c. (A) or two-dose s.c. (B) of AMG 139.

Figure 5

Mean (±SD) serum concentration-time profiles in cynomolgus monkeys after multiple i.v. or s.c. doses of AMG 139. Cynomolgus monkeys received 13 i.v. or s.c. (A) or 26 s.c. doses of AMG 139 (B) or vehicle every week.

Figure 6

Kinetics of the anti-KLH IgG response in monkeys following immunization with KLH. Male and female cynomolgus monkeys were given a dose of KLH at 1 mg per animal on day 30 and 60. Serum anti-KLH IgG titres were measured by elisa. Symbols represent individual results. Lines represent the group median. Responses in the AMG 139-treated animals (combined sexes) were comparable with the responses of the controls after both the primary and secondary immunization with KLH when animals with pre-existing anti-KLH titres were excluded. Median values below the assay cut-off point were set to one-half of the assay cut-point.