- J Clin Oncol. 2003 Jan 1;21(1):123-8.
Weekly high-dose calcitriol and docetaxel in metastatic androgen-independent prostate cancer.
Beer TM, Eilers KM, Garzotto M, Egorin MJ, Lowe BA, Henner WD.
Oregon Health & Science University and Portland VA Medical Center, Portland, OR 97239, USA.
To determine the safety and efficacy of weekly high-dose oral
calcitriol (Rocaltrol, Roche Pharmaceuticals, Basel, Switzerland) and
docetaxel (Taxotere, Aventis Pharmaceuticals, Bridgewater, NJ) in
patients with metastatic androgen-independent prostate cancer (AIPC).
PATIENTS AND METHODS: Thirty-seven patients were treated with oral
calcitriol (0.5 micro g/kg) on day 1 followed by docetaxel (36 mg/m(2))
on day 2, repeated weekly for 6 weeks of an 8-week cycle. Patients
maintained a reduced calcium diet and increased oral hydration.
Prostate-specific antigen (PSA) response was the primary end point,
which was defined as a 50% reduction in PSA level confirmed 4 weeks
RESULTS: Thirty of 37 patients (81%; 95% confidence interval
[CI], 68% to 94%) achieved a PSA response. Twenty-two patients (59%;
95% CI, 43% to 75%) had a confirmed > 75% reduction in PSA. Eight of
the 15 patients with measurable disease (53%; 95% CI, 27% to 79%) had a
confirmed partial response. Median time to progression was 11.4 months
(95% CI, 8.7 to 14 months), and median survival was 19.5 months (95%
CI, 15.3 months to incalculable). Overall survival at 1 year was 89%
(95% CI, 74% to 95%). Treatment-related toxicity was generally similar
to that expected with single-agent docetaxel. Pharmacokinetics of
either calcitriol or docetaxel were not affected by the presence of its
companion drug in an exploratory substudy.
CONCLUSION: The combination
of weekly oral high-dose calcitriol and weekly docetaxel is a
well-tolerated regimen for AIPC. PSA and measurable disease response
rates as well as time to progression and survival are promising when
compared with contemporary phase II studies of single-agent docetaxel
in AIPC. Further study of this regimen is warranted.