A total of five events with fatal outcome occurred as follows: one Grade 5 event in the 2.0 mg/kg dosing cohort: acute myocardial infarction (considered unrelated to study drug by the investigator); three Grade 5 events in the 2.7 mg/kg dosing cohort: one cardiac arrest (considered unrelated to study drug by the investigator) and two events of pneumonitis. In addition, a patient in the 2.7 mg/kg dosing cohort had a Grade 3 pleural effusion that is recorded as having a fatal outcome. The latter three deaths are being investigated, as follow-up is incomplete on this ongoing trial.