- Evidence of any significant clinical disorder or laboratory finding that renders the participant unsuitable for receiving an investigational new drug including clinically significant or unstable hematologic, hepatic, cardiovascular (including history of ventricular fibrillation or ventricular tachycardia), pulmonary, gastrointestinal, endocrine, metabolic, renal, or other systemic disease or laboratory abnormality. Abnormal liver function test, including AST, ALT, total bilirubin, or prothrombin time. The rationale is that retinoids can be hepatotoxic.