- Any of the following: hypocalcemia; severe malabsorption syndrome; moderate or severe hypertension which is uncontrolled; new onset angina or myocardial infarction within six months of entry into the study; evidence for impaired renal function defined as creatinine clearance <35 ml/min or serum creatinine greater than 1.6 mg/dL; organ transplantation; or other significant end organ diseases (genitourinary, cardiovascular, endocrine, hepatic, psychiatric, renal, hematologic, or pulmonary) which, in the opinion of the investigator, may pose an added risk to the patient or impair the patient's ability to complete the trial