Weekly high-dose calcitriol and docetaxel in metastatic androgen-independent prostate cancer.

PURPOSE: 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 later. 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.

Phase I study of weekly mitoxantrone and docetaxel before prostatectomy in patients with high-risk localized prostate cancer.

PURPOSE: The purpose is to determine the dose-limiting toxicity (DLT) and maximum-tolerated dose (MTD) of mitoxantrone and docetaxel administered weekly before prostatectomy in men with localized prostate cancer at high risk for recurrence. EXPERIMENTAL DESIGN: Twenty-two patients were treated with four cycles of docetaxel 35 mg/m(2) and increasing doses of mitoxantrone starting at 2 mg/m(2) repeated weekly for 3 weeks of a 4-week cycle before prostatectomy. The MTD was defined as that dose at which fewer than one-third of patients experienced a DLT (>or=grade 4 hematological or >or=>grade 3 nonhematological toxicity). Changes in serum prostate-specific antigen and serum testosterone, and pathological outcome with surgery were secondary endpoints. RESULTS: The MTD for mitoxantrone in combination with this dose of docetaxel was 4 mg/m(2). Neutropenia was the DLT for the combination. Ten of 12 patients treated at the MTD completed the planned 16 weeks of chemotherapy, whereas 2 discontinued therapy early because of toxicity. The median reduction in PSA was 41% (range, 4-88%). Serum testosterone levels remained constant postchemotherapy. CONCLUSIONS: In this patient population, the planned Phase II regimen is 4 mg/m(2) mitoxantrone and 35 mg/m(2) docetaxel weekly for 3 of every 4 weeks. Delivery of this regimen before prostatectomy is feasible with acceptable toxicity. Additional studies are needed to determine whether this combined modality approach will reduce cancer recurrence rates in this high-risk population. Because extent of disease and exposure to prior therapy may impact treatment tolerance these safety data may not be applicable to patients with advanced prostate cancer.

Randomized study of high-dose pulse calcitriol or placebo prior to radical prostatectomy.

BACKGROUND: Cancer chemoprevention trials require enormous resources due to the large numbers of patients and the years of follow-up needed to achieve sufficient statistical power. Examination of candidate prevention agents using biomarkers as surrogate end points has been proposed as a method to rapidly identify promising agents for prevention trials. Treatment of patients with candidate agents prior to scheduled biopsy or surgical resection of malignancy allows for direct examination of the treatment effects on tumor tissue. In this study, we selected this approach to test several hypotheses about the effect of calcitriol (1,25-dihydroxycholecalciferol), the active form of vitamin D, on early-stage human prostate cancer. METHODS: After selection of surgical treatment for histologically confirmed adenocarcinoma of the prostate, patients were randomized to either calcitriol 0.5 mug/kg or placebo weekly for 4 weeks. The expression levels of the vitamin D receptor (VDR), proliferating cell nuclear antigen, PTEN (MMAC1/TEP1), c-Myc, transforming growth factor (TGF) beta receptor type II (TGFbeta RII), and Bcl-2 were quantified using immunohistochemistry in the patients' prostate specimens post surgery. RESULTS: Thirty-seven of 39 prostate tumors were evaluable for molecular end points. VDR expression was reduced in patients treated with calcitriol (mean, 75.3% of cells) compared with those that received placebo (mean, 98.6%; P = 0.005). Calcitriol treatment did not result in a statistically significant change in the fraction of cells expressing TGFbeta RII, PTEN, or proliferating cell nuclear antigen. Bcl-2 and c-Myc expression was at the lower limits of detection in both the calcitriol group and the placebo group; therefore, we were unable to determine whether drug treatment induced a significant change in these biomarkers. CONCLUSIONS: High-dose calcitriol down-regulates VDR expression in human prostate cancer. Further study is needed to determine the biological consequences of VDR down-regulation in prostate cancer. This study shows that the use of the preprostatectomy model is feasible and can be used to test the effect of candidate chemopreventive agents on prostate cancer.

Ten-year follow-up of neoadjuvant therapy with goserelin acetate and flutamide before radical prostatectomy for clinical T3 and T4 prostate cancer: update on Southwest Oncology Group Study 9109.

OBJECTIVE: To update the results with 10-year data of a phase II prospective trial of neoadjuvant hormonal therapy with goserelin acetate and flutamide followed by radical prostatectomy for locally advanced prostate cancer (SWOG 9109). The optimal management for clinical stage T3 and T4 N0,M0 prostate cancer is uncertain. MATERIALS AND METHODS: Sixty-two patients with clinical stage T3 and T4 N0,M0 prostate cancer were enrolled. Cases were classified by stage T3 vs T4 and by volume of disease (bulky >4 cm and nonbulky ≤ 4 cm). RESULTS: Fifty-five of 61 eligible patients completed the trial with radical prostatectomy after neoadjuvant androgen deprivation therapy (ADT). The median preoperative prostate-specific antigen value was 19.8 ng/mL, and 67% of patients had a Gleason score of ≥ 7. Among 41 patients last known to be alive, median follow-up is 10.6 years (range 5.1-12.6). In all, 38 patients have had disease progression (30/55, 55%) or died without progression (8/55, 15%) for a 10-year progression-free survival (PFS) estimate of 40% (95% CI 27-53). Median PFS was 7.5 years, and median survival has not been reached. The 10-year overall survival (OS) estimate is 68% (95% CI 56-80). CONCLUSIONS: In this small, prospective phase II study, neoadjuvant hormonal therapy with goserelin acetate and flutamide followed by radical prostatectomy achieves long-term PFS and OS comparable with alternative treatments. This approach is feasible and may be an alternative to a strategy of combined radiation and ADT.

High-dose weekly oral calcitriol in patients with a rising PSA after prostatectomy or radiation for prostate carcinoma.

BACKGROUND: In preclinical systems, calcitriol, the natural vitamin D receptor (VDR) ligand, has been found to demonstrate antiproliferative effects, although concentrations > 1 nM are required. Unlike daily dosing, weekly administration of oral calcitriol can safely achieve such blood calcitriol concentrations. This study sought to define the long-term toxicity of this regimen and measure its effect on serum prostate specific antigen (PSA) levels in patients with hormone-naïve prostate carcinoma. METHODS: Patients with a rising serum PSA after prostatectomy and/or radiation and no prior systemic therapy for prostate carcinoma recurrence maintained a reduced calcium diet and received calcitriol 0.5 microg/kg orally once each week until a maximum of a four-fold increase in the PSA. RESULTS: Twenty-two patients received treatment for a median of 10 months (range, 2-25+ months). Treatment was well tolerated with no Grade >or= 3 toxicity and no hypercalcemia or renal calculi. No patient had a PSA response (50% reduction confirmed 4 weeks later). Three patients (14%, 95% CI 0-28%) had confirmed reductions in the PSA ranging from 10% to 47%. Statistically significant increases in the PSA doubling time (PSADT) were seen in three additional patients and no patient had a shorter PSADT after starting treatment. For the entire study population, the median PSADT increased from 7.8 months to 10.3 months (P = 0.03 by Wilcoxon signed rank test). CONCLUSIONS: Weekly high-dose calcitriol was found to be safe. The primary efficacy endpoint of 50% reduction in the serum PSA was not achieved with this therapy. Randomized studies are needed to further examine the impact of this therapy on prostate carcinoma progression.

Neoadjuvant therapy before radical prostatectomy for clinical T3/T4 carcinoma of the prostate: 5-year followup, Phase II Southwest Oncology Group Study 9109.

PURPOSE: Several investigators have examined the role of hormonal therapy before definitive local therapy for locally advanced prostate cancer to improve outcome. We evaluated the resectability rate and clinical response rate to 16 weeks of total androgen blockage therapy for clinically locally prostate cancer before radical prostatectomy, and progression-free survival in this multi-institutional study. MATERIALS AND METHODS: Southwest Oncology Group 9109 was a phase II feasibility study designed to treat patients with clinical stage C prostate cancer (T3, T4, N0 and M0). Cases were classified by stage T3 versus T4 and bulky (greater than 4 cm.) versus nonbulky (or less 4 cm.) disease. The neoadjuvant agents used were goserelin and flutamide before radical prostatectomy. RESULTS: A total of 62 patients were accrued to the study and 1 patient was ineligible. There were 2 protocol deviations and these patients refused to undergo prostatectomy after hormonal therapy. Four patients went off protocol treatment because they were not considered surgical candidates. The racial distribution was 72% white, 20% black, 7% Hispanic and 2% Asian. Clinical stage at diagnosis was T3 in 97% and T4 in 3% of cases. Of the patients 39% were diagnosed with bulky disease. Of the 61 eligible patients 55 (90%) underwent a prostatectomy. The 5-year progression-free survival estimate was 70% (24 of 61 cases failed) and the 5-year survival estimate was 90% (11 of 61 deaths). Most of the patients in this trial would have been considered inoperable and referred to radiation oncology. CONCLUSIONS: Neoadjuvant hormonal therapy followed by radical prostatectomy is reasonable and appropriate for clinical stage T3 prostate cancer. A progression-free and overall 5-year survival of 70% and 90%, respectively, compares favorably to Radiation Therapy Oncology Group neoadjuvant trial outcomes for this stage of prostate cancer.

Tumour-induced polarization of tumour vaccine-draining lymph node T cells to a type 1 cytokine profile predicts inherent strong immunogenicity of the tumour and correlates with therapeutic efficacy in adoptive transfer studies.

Previously we have shown that vaccination with the poorly immunogenic B16BL6-D5 melanoma (D5) elicits a dominant type 2 (T2) cytokine response that fails to protect the host from a subsequent tumour challenge. Here we investigated whether the inherent immunogenicity of a tumour can be correlated with its ability to bias the anti-tumour cytokine response towards either a type 1 (T1) or a T2 profile. The immune response to six tumours of different inherent immunogenicity was assayed. By isolating l-selectinlow T cells from tumour vaccine draining lymph nodes (TVDLN), it was possible to detect tumour-specific cytokine responses from both immunogenic, poorly immunogenic and non-immunogenic tumours. Immunogenic tumours (MCA-304, MCA-309, MPR-4) induced a predominant tumour-specific T1 cytokine response. In contrast, weakly (MCA-310, MPR-3) and poorly/non-immunogenic tumours (MPR-5, D5) sensitized T cells with a predominant tumour-specific T2 cytokine response. A significant correlation (P < 0.025) between immunogenicity and the ratio of tumour-specific interferon-gamma : interleukin-4 (IL-4) secretion by TVDLN T cells was identified. We then documented that non-therapeutic T cells primed by the poorly immunogenic D5, recognized "tumour-rejection" antigens and that reprogramming their cytokine response, by in vitro culture with IL-12 and anti-IL-4, to a T1 profile uncovered therapeutic efficacy. In contrast, TVDLN T cells primed by a therapeutic vaccine lose therapeutic efficacy when cultured with IL-4. These results provide insights into the development of a protective anti-tumour immune response and strengthen the hypothesis that a T1 cytokine response is critical for T-cell-mediated tumour regression.