High dose pulse calcitriol, docetaxel and estramustine for androgen independent prostate cancer: a phase I/II study.
OBJECTIVE
We determined the safety and preliminary efficacy of the combination of high dose pulse calcitriol (1,25-dihydroxycholecalciferol) with a standard regimen of docetaxel plus estramustine in patients with metastatic androgen independent prostate cancer.


METHODS
Patients were treated with 60 microg calcitriol orally on day 1, 280 mg estramustine orally 3 times daily on days 1 to 5 and 60 mg/m docetaxel on day 2 (70 mg/m after cycle 1) every 21 days for up to 12 cycles. Patients also received 325 mg aspirin and 1 or 2 mg warfarin orally daily. Regimen safety was assessed in the first 6 patients and a dose de-escalation scheme for calcitriol was planned if dose limiting toxicities were noted during treatment cycle 1 in greater than a third of patients.


RESULTS
A total of 24 patients, including 11 who were chemotherapy naïve and 13 who had previously been treated with docetaxel, were evaluable for toxicity and 22 for prostate specific antigen decrease data. The regimen was generally well tolerated. Treatment related grades 3 or greater toxicity seen in more than 1 patient included hypophosphatemia in 16.7% and neutropenia in 12.5%. Four patients had thromboembolic complications. Asymptomatic hypercalcemia was seen in 4 patients, including grades 2 and 1 in 1 and 3, respectively. Six of 11 evaluable, chemotherapy naïve patients (55%) met prostate specific antigen response criteria. One of 11 patients (9%) treated with prior docetaxel met these criteria.


CONCLUSIONS
High dose calcitriol may be safely added to docetaxel and estramustine administered on a 21-day schedule.
Tiffany
Natasha M
NM
Division of Hematology and Medical Oncology, Oregon Health Sciences University and Portland Veterans Affairs Medical Center, Portland 97239, USA.
Ryan
Christopher W
CW
Garzotto
Mark
M
Wersinger
Emily M
EM
Beer
Tomasz M
TM
D000284:Administration, Oral; D000368:Aged; D000971:Antineoplastic Combined Chemotherapy Protocols / Q000627:therapeutic use* / Q000633:toxicity; D001859:Bone Neoplasms / Q000097:blood / Q000188:drug therapy / Q000473:pathology / Q000556:secondary*; D002117:Calcitriol / Q000008:administration & dosage / Q000633:toxicity; D018450:Disease Progression; D000077143:Docetaxel; D004305:Dose-Response Relationship, Drug; D004334:Drug Administration Schedule; D004961:Estramustine / Q000008:administration & dosage / Q000633:toxicity; D005500:Follow-Up Studies; D006801:Humans; D007262:Infusions, Intravenous; D008297:Male; D008875:Middle Aged; D009376:Neoplasms, Hormone-Dependent / Q000188:drug therapy / Q000473:pathology; D017430:Prostate-Specific Antigen / Q000097:blood; D011471:Prostatic Neoplasms / Q000097:blood / Q000188:drug therapy* / Q000473:pathology; D043823:Taxoids / Q000008:administration & dosage / Q000633:toxicity; D016896:Treatment Outcome
D043823:Taxoids; D000077143:Docetaxel; D004961:Estramustine; D017430:Prostate-Specific Antigen; D002117:Calcitriol