Multiple Ascending Doses of AMG 139 in Healthy and Crohn's Disease Subjects

Part A – Healthy Subjects: - Healthy male or female of non-reproductive potential subjects between 18 to 45 years-of-age - Body mass index (BMI) between 18 and 32 kg/m2 - Normal or clinically acceptable physical examination, clinical laboratory values, and ECG - Additional inclusion criteria apply Part B – Crohn’s Subjects: - Male or female subjects with CD between 18 to 55 years-of-age - Body mass index (BMI) between 18 and 32 kg/m2 - Normal or clinically acceptable physical examination (PE), clinical laboratory values, and ECG; clinically acceptable PE includes evidence of mild to severe CD - Diagnosis of ileal or ileo-colonic CD for a minimum of 6 months - Mild to severe CD defined by a Crohn’s Disease Activity Index (CDAI) score equal to or greater than 180 and equal to or less than 450 - Elevated fecal calprotectin and CRP - Additional inclusion criteria apply

Parts A – Healthy Subjects: - History or evidence of a clinically significant disorder (including psychiatric), condition or disease that would pose a risk to subject safety or interfere with the study evaluation, procedures or completion; - Recent or on-going infection(s) - Underlying condition(s) that predisposes the subject to infections - History of malignancy of any type - Additional exclusion criteria apply Part B only – Crohn’s Subjects: - History or evidence of a clinically significant disorder (including psychiatric), condition or disease that would pose a risk to subject safety or interfere with the study evaluation, procedures or completion; - Recent or on-going infection(s) - Underlying condition(s) that predisposes the subject to infections - History of malignancy of any type - Additional exclusion criteria apply