Phase II trial of oral 1,25-dihydroxyvitamin D (calcitriol) in hormone refractory prostate cancer

J L Osborn; G G Schwartz; D C Smith; R Bahnson; R Day; D L Trump

doi:10.1016/1078-1439(95)00061-5

Phase II trial of oral 1,25-dihydroxyvitamin D (calcitriol) in hormone refractory prostate cancer

Urol Oncol. 1995 Sep-Oct;1(5):195-8. doi: 10.1016/1078-1439(95)00061-5.

Authors

J L Osborn¹, G G Schwartz, D C Smith, R Bahnson, R Day, D L Trump

Affiliation

¹ University of Pittsburgh Cancer Institute, Prostate and Urologic Cancer Center, Pittsburgh, Pennsylvania, USA; Division of Medical Oncology, Department of Medicine, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, USA.

PMID: 21224117
DOI: 10.1016/1078-1439(95)00061-5

Abstract

Epidemiologic and experimental data support a role for 1,25-dihydroxyvitamin D(3) in the growth regulation of prostate cancer. We conducted a phase II clinical trial evaluating calcitriol (1,25(OH)(2)D(3)) in patients with hormone refractory prostate cancer. We enrolled 14 patients in this study. 1,25(OH)(2)D(3) was initiated at a daily oral dose of 0.5 μg and escalated to 1.5 μg daily. No objective responses were observed. However, in two patients decreases of 25% and 45% in prostate specific antigen levels were seen. Hypercalcemia was the predominant toxicity. We conclude that 1,25(OH)(2)D(3) given in this manner is inactive in advanced prostate cancer. Dose escalation of oral 1,25(OH)(2)D(3) is limited by hypercalcemia.