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Phase II trial of high-dose, intermittent calcitriol (1,25 dihydroxyvitamin D3) and dexamethasone in androgen-independent prostate cancer
Article first published online: 5 APR 2006
Copyright © 2006 American Cancer Society
Volume 106, Issue 10, pages 2136–2142, 15 May 2006
How to Cite
Trump, D. L., Potter, D. M., Muindi, J., Brufsky, A. and Johnson, C. S. (2006), Phase II trial of high-dose, intermittent calcitriol (1,25 dihydroxyvitamin D3) and dexamethasone in androgen-independent prostate cancer. Cancer, 106: 2136–2142. doi: 10.1002/cncr.21890
- Issue published online: 27 APR 2006
- Article first published online: 5 APR 2006
- Manuscript Accepted: 6 JAN 2006
- Manuscript Revised: 14 DEC 2005
- Manuscript Received: 10 AUG 2005
- National Cancer Institute, and CaPCURE. Grant Numbers: CA85142, CA95045, CA67267
- prostate cancer;
- Phase II trial
Data suggest that vitamin D plays a role in the treatment and prevention of prostate cancer. The combination of high-dose, intermittent calcitriol (1,25 dihydroxyvitamin D3) plus dexamethasone was studied based on evidence that dexamethasone potentiates the antitumor effects of calcitriol and ameliorates hypercalcemia.
Oral calcitriol was administered weekly, Monday, Tuesday, and Wednesday (MTW), at a dose of 8 μg, for 1 month, at a dose of 10 μg every MTW for 1 month, and at a dose of 12 μg every MTW thereafter. Dexamethasone at a dose of 4 mg was administered each Sunday, and MTW weekly. Calcium and creatinine were determined weekly and radiographs of the urinary tract were performed every 3 months. All patients were considered evaluable for toxicity.
Forty-three men with androgen-independent prostate cancer were entered; 37 received at least 1 month of calcitriol given at a dose of 12 μg every day × 3 per week. The majority of patients had bone metastases and rising prostate-specific antigen (PSA) levels. All had an Eastern Cooperative Oncology Group performance status of 0 or 1. Eight patients (19%) experienced partial responses by PSA criterion (PSA decline of ≥50%, persisting for ≥28 days). Subjective clinical improvement occurred in some patients. Toxicity was minimal: urinary tract stones in 2 patients; and a readily reversible, CTC (v.3.0) Grade <2 creatinine increase in 4 patients. Throughout the study only 4 patients ever had a serum calcium level >11.0 mg/dL and no patient had a calcium level >12.0 mg/dL.
The response rate reported in the current study (19%) was not found to be clearly higher than expected with dexamethasone alone. High-dose intermittent calcitriol plus dexamethasone appears to be safe, feasible, and has antitumor activity. Cancer 2006. © 2006 American Cancer Society.