Clinical pharmacology of AMG 181, a gut-specific human anti-α4β7 monoclonal antibody, for treating inflammatory bowel diseases.

Aims AMG 181 pharmacokinetics/pharmacodynamics ( PK/ PD), safety, tolerability and effects after single subcutaneous (s.c.) or intravenous (i.v.) administration were evaluated in a randomized, double-blind, placebo-controlled study. Methods Healthy male subjects ( n= 68) received a single dose of AMG 181 or placebo at 0.7, 2.1, 7, 21, 70 mg s.c. (or i.v.), 210 mg s.c. (or i.v.), 420 mg i.v. or placebo. Four ulcerative colitis ( UC) subjects ( n= 4, male : female 2:2) received 210 mg AMG 181 or placebo s.c. (3:1). AMG 181 concentration, anti- AMG 181-antibody ( ADA), α4β7 receptor occupancy ( RO), target cell counts, serum C-reactive protein, fecal biomarkers and Mayo score were measured. Subjects were followed 3-9 months after dose. Results Following s.c. dosing, AMG 181 was absorbed with a median tmax ranging between 2-10 days and a bioavailability between 82% and 99%. Cmax and AUC increased dose-proportionally and approximately dose-proportionally, respectively, within the 70-210 mg s.c. and 70-420 mg i.v. ranges. The linear β-phase t1/2 was 31 (range 20-48) days. Target-mediated disposition occurred at serum AMG 181 concentrations of less than 1 μg ml−1. The PD effect on α4β7 RO showed an E C50 of 0.01 μg ml−1. Lymphocytes, eosinophils, CD4+ T cells and subset counts were unchanged. AMG 181-treated UC subjects were in remission with mucosal healing at weeks 6, 12 and/or 28. The placebo-treated UC subject experienced colitis flare at week 6. No ADA or AMG 181 treatment-related serious adverse events were observed. Conclusions AMG 181 has PK/ PD, safety, and effect profiles suitable for further testing in subjects with inflammatory bowel diseases. [ABSTRACT FROM AUTHOR]