Subject has a history of unexplained loss of consciousness or transient ischemic attack within 12 months of treatment start loss of consciousness or transient ischemic attack within 12 months of randomization History of seizure or any condition that may predispose to seizures at any time in the past. History of loss of consciousness or transient ischemic attack within 12 months of screening History of loss of consciousness or transient ischemic attack within twelve (12) months of enrollment History of loss of consciousness or transient ischemic attack within 12 months prior to enrollment Any history of seizure; history of loss of consciousness or transient ischemic attack within 12 months of starting the study drug Subject with a history of loss of consciousness or transient ischemic attack ? 12 months of study drug initiation. For Cohort C: Has a history of loss of consciousness within 12 months of the screening visit Subject has history of loss of consciousness or transient ischemic attack within 12 months prior to day 1. The subject has a history of loss of consciousness, cerebrovascular accident, or transient ischemic attack within 12 months before the Day 1 visit. Subject has a history of loss of consciousness or transient ischemic attack within 12 months before the Day 1 visit. loss of consciousness or transient ischemic attack within 12 months of randomization History of loss of consciousness or transient ischemic attack within 12 months prior to enrollment unexplained loss of consciousness within the last 12 months, For Arm D only: History of seizure, unexplained loss of consciousness, transient ischemic attack within 12 months of enrollment, cerebral vascular accident, and any brain metastases History of loss of consciousness or transient ischemic attack within 12 months of enrollment History of stroke or head injury associated with loss of consciousness within 12 months of registration History of loss of consciousness or transient ischemic attack within past 12 months