1. Symptomatic arrhythmia (excluding anemia-related grade ≤ 2 sinusal tachycardia) or any arrhythmia requiring ongoing treatment, and/or prolonged grade ≥ 2 QT-QTc; or presence of unstable atrial fibrillation (according to the National Cancer Institute Common Terminology Criteria for the Classification of Adverse Events [NCI-CTCAE] v4.0). Patients on treatment for stable atrial fibrillation are allowed, provided they do not meet any other cardiac or prohibited drug exclusion criterion.