Inclusion Criteria

Patients must meet all of the following inclusion criteria to be eligible for participation in this study:

• Patients with advanced solid tumor malignancies
• Patients with prostate cancer are eligible 1) if they have had a prostatectomy or radiation therapy and have a rising PSA, 2) if they have androgen sensitive prostate cancer and are on hormone therapy, or 3) if they have androgen independent prostate cancer and have failed hormone therapy
• Patients with other types of malignancies will be required to have failed at least one potentially effective therapy prior to study entry
• Life expectancy > 3 months
• Age > 18 years

• The following laboratory results:

  • Adequate hematologic function
  • Adequate renal function
  • Adequate liver function
  • Negative urine pregnancy test (females of childbearing potential only)
• Willingness to use effective contraception by both males and females throughout the treatment period and for at least 2 months following treatment
• Signed informed consent form

Exclusion Criteria

Patients who meet any of the following exclusion criteria are not to be enrolled in this study:

• Significant active medical illness (other than current cancer) which in the opinion of the investigator would preclude protocol treatment
• History of cancer-related hypercalcemia, known hypercalcemia, or vitamin D toxicity
• Uncontrolled heart failure
• Kidney stones (calcium salt) within the past 5 years
• Prior investigational therapy within the past 30 days
• Prior use of calcitriol within the past 3 months or known hypersensitivity to calcitriol
• Concurrent active treatment for cancer with the exception of treatment for androgen-independent prostate cancer
• Excluded concomitant medications: calcium- or magnesium-containing antacids, bile-resin binders, bisphosphonates, or calcium supplements; ketoconazole or related compounds