6. Adequate hepatic function defined as: a) total bilirubin </= 1.5 times the institutional upper limit ULN; b) alanine aminotransferase (ALT) and aspartate aminotransferase (AST) </= 2.0 times the institutional ULN; c) Exception: patients with primary liver tumors or known liver metastases: </= 3.0 times the institutional ULN for AST and ALT