Prior isotope therapy with strontium-, samarium or radium- within weeks of treatment start Radiotherapy = weeks prior to enrollment Systemic strontium-, samarium-, rhenium-, or rhenium- for bone metastases within weeks prior to initiation of study treatment Systemic radiation therapy within weeks, prior focal radiotherapy within weeks, or radiopharmaceuticals (strontium, samarium) within weeks prior to the first dose of study treatment. Previous treatment with Samarium- or Strontium-. Previous treatment with Samarium-, Strontium-, Rhenium- or Radium- within months of starting (i.e., Cycle Day ) EC Prior systemic radiotherapy with strontium-, samarium-, rhenium- or rhenium-. Patients who have previously received mithramycin, strontium-, samarium- or rhenium Prior therapy with radium- or systemic radiotherapy (such as samarium, strontium) Following prior treatments are not eligible:\r\n* Use of any investigational agent within days preceding enrollment\r\n* Treatment with cytotoxic chemotherapy within previous weeks\r\n* Failure to achieve =< grade adverse events (AE) resolution from cytotoxic chemotherapy administered more than weeks previous (however, ongoing neuropathy is permitted)\r\n* Received systemic therapy with radionuclides (e.g., strontium-, samarium-, rhenium-, or rhenium-, or Ra- dichloride) for the treatment of bony metastases Received systemic therapy with radionuclides (e.g., strontium-, samarium-, rhenium-, or rhenium-, or radium Ra dichloride) for the treatment of bony metastases At least weeks must have elapsed from the use of strontium-, radium- or any investigational or approved immunotherapy (e.g., Provenge) prior to starting study drug At least weeks must have elapsed from the use of strontium-, radium-, samarium-, or immunotherapy (e.g., Provenge) prior to beginning protocol therapy Strontium-, samarium-, or radium- therapy within weeks of cycle , day Radium-, strontium-, or samarium- therapy within weeks of enrollment Prior therapy with strontium-, samarium, rhenium- etidronate, chemotherapy or androgen biosynthesis inhibitors for prostate cancer is not allowed. Previous immunologic, homeopathic, natural, or alternative medicine therapies are acceptable provided treatment ended greater than days prior to initiation of study drug Treatment with radiotherapy within the past weeks or radiopharmaceutical therapy (strontium, samarium) within the past weeks Systemic radiation therapy within weeks, prior focal radiotherapy within weeks, or radiopharmaceuticals (strontium, samarium) within weeks prior to the first dose of study treatment. Systemic radiation therapy within weeks, focal radiotherapy within weeks and radiopharmaceuticals (strontium, samarium) within weeks prior to first dose of study treatment. Systemic radiation therapy within weeks, prior focal radiotherapy within weeks, or radiopharmaceuticals (strontium, samarium) within weeks prior to the first dose of study treatment. Therapy with samarium-, strontium-, or radium- within weeks prior to first dose of study drug. Patients who received treatment with strontium- or samarium- are excluded, except prior samarium will be allowed provided it was administered > year ago and/or the patient has demonstrated the ability to\r\nreceive cytotoxic chemotherapy without excess myelosuppression after receiving samarium. Prior radiopharmaceutical therapy (e.g. radium-, strontium-, samarium-, etc) within the past days No history of radiopharmaceuticals (strontium, samarium) for prostate cancer treatment Has received treatment with focal radiotherapy within weeks, or radiopharmaceuticals (e.g., strontium, samarium) within weeks of receiving cyclophosphamide on Day - Prior use of Strontium- at any time or Samarium- within days prior to randomization Received systemic therapy with radionuclides (e.g. strontium-, samarium-, rhenium- or rhenium-) for the treatment of bone metastases Any prior therapy with radium-, samarium, or strontium No prior chemotherapy regimen; prior isotope therapy with strontium-, samarium or radium- (RAD) should be completed at least three months ( weeks) prior to treatment start