Inclusion Criteria

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