6. Significant organ dysfunction, including cardiac, renal, liver, CNS, pulmonary, vascular, gastrointestinal, endocrine, or metabolic (e.g., creatinine >1.6 mg/dL; ALT or AST > 1.5x the upper limit of normal; history of myocardial infarction, congestive heart failure, or arrhythmias within 6 months prior to study entry)