The investigator assessed the severity of each adverse event reported during the study. The assessment was based on the Amgen Standard Grading Scale: Mild: Aware of sign or symptom, but easily tolerated. Moderate: Discomfort enough to cause interference with usual activity. Severe: Incapacitating with inability to work or do usual activity. A Serious adverse event is defined as any untoward medical occurrence that, met at least 1 of the following serious criteria * Death; * Was life-threatening; * Required in-patient hospitalization or prolongation of existing hospitalization; * Resulted in persistent or significant disability/incapacity; * Was a congenital anomaly/birth defect; * Other medically important serious event. The investigator also assessed whether each adverse event was related to study drug administration based on clinical judgement.

TEAEs due to laboratory, electrocardiogram (ECG) and vital sign findings include any abnormal laboratory test results (hematology, clinical chemistry, or urinalysis) or electrocardiogram, or vital signs measurements, including those that worsened from baseline, that were considered clinically significant in the medical and scientific judgment of the investigator (ie, not related to progression of underlying disease).