Phase II trial of docetaxel/capecitabine in hormone-refractory prostate cancer

Background

Docetaxel is the most active single agent in the treatment of hormone-refractory prostate cancer (HRPC). Because of the preclinical and clinical evidence of synergy of capecitabine and docetaxel, it was hypothesized that this combination would be active and tolerable in HRPC.

Patient and Methods

Patients received docetaxel 60 mg/m² intravenously over 60 minutes on day 1 of each 21-day cycle and capecitabine 1000 mg/m² administered orally twice daily on days 1-14 of each cycle for a maximum of 8 cycles or until disease progression or intolerable toxicity. Seventy-seven patients were enrolled at 43 US Oncology sites. The median age was 69.3 years (range, 48-86 years); 86% were white, and the Eastern Cooperative Oncology Group performance status scores of 0 and 1 were 49% and 51%, respectively. Sixty-nine (90%) patients were evaluable for prostate-specific antigen response.

Results

Overall, 41% of patients had a decreased prostate-specific antigen level ≥ 50%. There were 4 complete responses (6%), 24 partial responses (35%), 29 incidences of stable disease (43%), and 11 incidences of progressive disease (16%). Nine patients had stable disease ≥ 6 months, and the clinical benefit rate was 54%. The median time to response was 1.5 months (range, 1-6 months), and the median duration of response was 5.2 months (range, 1-16.9 months). The estimated survival at 12 and 24 months was 65% and 22%, respectively, with a median survival of 17 months (range, < 1-27 months). There were no treatment-related deaths. Grade 3/4 toxicities included neutropenia (50%), leukopenia (22%), hand-foot syndrome (17%), fatigue (11%), and nausea (11%).

Conclusion

Docetaxel/capecitabine is an active and tolerable combination in HRPC. Toxicity was acceptable and anticipated. Response rate and survival are comparable with other docetaxel combinations.     

Phase II study of mitoxantrone and ketoconazole for hormone-refractory prostate cancer

BACKGROUND: Doxorubicin plus ketoconazole has exhibited significant activity in patients with advanced prostate cancer. However, overall and cardiac-specific toxicity was reported to be high. Mitoxantrone has activity similar to that of doxorubicin, is less cardiotoxic, and is widely used to treat prostate cancer. The current study sought to evaluate the toxicity and activity of mitoxantrone plus ketoconazole in a cohort of patients with hormone-refractory prostate cancer. METHODS: Progression after medical or surgical castration and, for those patients receiving antiandrogens, progression after withdrawal was required, as was objective evidence of metastasis, castrate levels of testosterone, an Eastern Cooperative Oncology Group (ECOG) performance status of 0 to 2, and intact cardiac function. After enrollment onto a multicenter local consortium study, subjects were treated with mitoxantrone at a dose of 12 mg/m2 intravenously every 3 weeks plus continuous oral ketoconazole at a dose of 400 mg 3 times daily and ascorbic acid at a dose of 250 mg. Replacement doses of hydrocortisone were given. RESULTS: For 40 enrolled subjects, the median prostate-specific antigen and ECOG performance status were 68 and 1, respectively, 53% had Gleason scores of 8 to 10, and all had metastasis. Predominant Grade 3/4 toxicities were: neutropenia in 13%, neutropenic fever in 10%, and anemia in 13%. Of 37 evaluable patients, 8% achieved a complete remission (CR) and 62% achieved a partial remission (PR), for a CR plus PR rate of 70%. For soft tissue and bone disease, overall response rates were 13% and 8%, respectively. The median progression-free survival and overall survival were 10 months and 18 months, respectively. CONCLUSIONS: Mitoxantrone plus ketoconazole is well tolerated, is active in hormone-refractory prostate cancer, and should be studied further.     

A Phase II trial of suramin monthly x 3 for hormone-refractory prostate carcinoma

BACKGROUND: The goal of the current study was to determine the prostate-specific antigen (PSA) and objective response rates and the pharmacokinetics associated with a monthly x 3 one-hour infusion of suramin in 58 patients with hormone-refractory prostate carcinoma. METHODS: A PSA response was defined as a > 50% reduction in the PSA level from baseline for at least 3 consecutive evaluations over a minimum of 6 weeks. The suramin dose was 2400 mg/m(2) taken intravenously on Day 1, 1620 mg/m(2) on Day 29, and 1292 mg/m(2) on Day 57. All patients received 0.5 mg dexamethasone twice daily. RESULTS: Among 56 evaluable patients (median entry PSA level, 229.5 ng/mL), there were 21 PSA responders (37.5%). Among 27 patients with measurable disease, there were 5 responders (4 partial and 1 complete). The median overall survival time was 15.3 months. Grade III fatigue (14.1%) was the predominant toxicity observed. Suramin plasma levels remained high even 3 months after treatment was discontinued. Among the 12 evaluable patients who previously had received chemotherapy, the PSA response rate was 42%; one response was observed among 4 patients with measurable disease, and the median survival was 12 months. CONCLUSIONS: Monthly bolus suramin was well tolerated, reduced PSA levels, and induced objective responses, even in patients who previously had received chemotherapy.     

Phase II trial of estramustine phosphate and oral etoposide in patients with hormone-refractory prostate cancer

Background: There is a need for active agents with a bettersafety profile than docetaxel, yet good activity, for patientswith hormone-refractory prostate cancer (HRPC). We carried outa phase II trial to determine the activity and safety of estramustineplus oral etoposide in HRPC. Patients and methods: Patients were given estramustine (280mg twice daily) and etoposide (100 mg/day, days 1–21)in 28-day cycles until disease progression or unacceptable toxicity.Primary end points were overall response rate and safety, asdetermined by prostrate-specific antigen (PSA) levels and lesionassessment. Results: From November 2001 to February 2007, 75 patients wereenrolled. All patients were assessable for safety; 17 (22.6%)had grade 3/4 toxicity. PSA response was assessable in 69, 14of whom had a >50% reduction in PSA. Of 10 patients withone or more measurable lesions, two (20%) had partial responseand two (20%) disease stabilization. Overall, median time toprogression was 4.4 months (range 1 week–43 months); mediansurvival was 23 months (range 3 weeks–64+ months). Conclusions: Estramustine plus etoposide is active and has amanageable safety profile in patients with HRPC. In asymptomaticpatients with nonaggressive disease this combination could beuseful to delay the start of more demanding treatments. Key words: estramustine phosphate, etoposide, hormone-refractory prostate cancer     

A randomized Phase II trial of the antiangiogenic agent SU5416 in hormone-refractory prostate cancer.

PURPOSE: To assess the activity of the antiangiogenic agent and VEGFR2 inhibitor SU5416 in hormone-refractory prostate cancer. Patients and Methods: Thirty-six chemotherapy na?ve patients were randomized to treatment with SU5416 (145 mg/m(2)) and dexamethasone premedication or dexamethasone alone. Patients in the control arm could cross over to experimental therapy after progression. Prostate-specific antigen (PSA) was measured every 2 weeks, and radiological evaluation was performed every 8 weeks. In vitro assessment of SU5416 on PSA secretion was assessed in the LNCaP cell line. Baseline serum basic fibroblast growth factor and plasma vascular endothelial growth factor (VEGF) were explored as prognostic factors. RESULTS: VEGF receptor-2 expression is detectable in prostate cancer cell lines, and SU5416 inhibited in vitro PSA secretion. No effect of SU5416 on PSA secretion or time to progression is detectable in patients. VEGF and basic fibroblast growth factor were not prognostic. Headache and fatigue were the most common SU5416 toxicities, but hyperglycemia, hyponatremia, lymphopenia, infection, and adrenal suppression, all attributable to steroids and the required central line, were common. CONCLUSION: No disease modifying effects of SU5416 were detectable in this small study. Modest toxicity, an inconvenient administration schedule, and availability of other VEGFR-targeted agents support the decision to halt further evaluation of SU5416 in prostate cancer.     

Gefitinib-trastuzumab combination on hormone-refractory prostate cancer xenograft

New drugs and new combinations of drugs have recently shown promising clinical activity in hormone refractory prostate cancer. We studied the association of gefitinib with trastuzumab on the androgen-refractory prostate cancer cell line DU145 expressing both epidermal growth factor receptor (EGFR) and HER-2. Drug combinations with radiotherapy (RT) were considered along with the analysis of factors linked to cell proliferation and apoptosis. The antitumour effects of gefitinib were more pronounced than those observed with trastuzumab. In mice receiving the gefitinib-trastuzumab combination, reduction in tumour volume was inferior to that predicted by the observed impact of the agents alone. The presence of trastuzumab markedly attenuated the relative increase on p27 expression and the Bax:Bcl2 ratio induced by gefitinib. The combination gefitinib-RT had similar antitumour effects as those predicted by the impact of the individual treatments, whereas the effect of the trastuzumab-RT combination was inferior to that predicted by the individual effects. The present data should be borne in mind when designing new clinical schedules for treatment of hormone-refractory prostate cancer including the use of HER inhibitors.     

Weekly docetaxel and bortezomib as first-line treatment for patients with hormone-refractory prostate cancer: a Minnie Pearl Cancer Research Network phase II trial

Background

Docetaxel is currently the standard first-line treatment in patients with hormone-refractory prostate cancer (HRPC). Bortezomib, the first proteasome inhibitor in clinical use, demonstrated activity against prostate cancer in phase I trials. For this reason, we evaluated the efficacy of docetaxel plus bortezomib in the first-line treatment of patients with HRPC.

Patients and Methods

Between February 2004 and May 2005, 63 eligible patients entered this phase II trial. All patients had metastatic adenocarcinoma of the prostate that had progressed on hormonal therapy. All patients received docetaxel 30 mg/m² and bortezomib 1.6 mg/m² on days 1, 8, and 15 of a 28-day cycle. Patients were reevaluated after 8 weeks of treatment; responding and stable patients continued treatment until tumor progression.

Results

Sixty patients (95%) received ≤ 2 courses of treatment and were evaluable for response. Fifteen patients (25%; 95% confidence interval, 15%-38%) had a > 50% decrease in serum prostate-specific antigen level with treatment; the median response duration was 8 months. The median progression-free and overall survival times for the entire group were 4.1 months and 13.8 months, respectively; 20% of patients were alive at 2 years. The regimen was well tolerated, with uncommon grade 3/4 toxicity.

Conclusion

Treatment with this combination of weekly docetaxel and bortezomib showed no suggestion of improved efficacy versus previous results with docetaxel alone. Bortezomib has minimal activity in patients with HRPC and is unlikely to make any impact on treatment efficacy.     

Phase II trial of oral estramustine, oral etoposide, and intravenous paclitaxel in hormone-refractory prostate cancer.

PURPOSE: To evaluate the combination of intravenous (IV) paclitaxel, oral estramustine, and oral etoposide in patients with advanced hormone-refractory prostate cancer. PATIENTS AND METHODS: Forty patients with carcinoma of the prostate that was progressing despite hormonal therapy and who had undergone antiandrogen withdrawal (if previously treated with an antiandrogen) were enrolled onto this phase II trial. Patients were treated with oral estramustine 280 mg tid and oral etoposide 100 mg/d for 7 days, with paclitaxel 135 mg/m(2) IV over 1 hour on day 2 of each 21-day treatment cycle. Patients received a maximum of six cycles of therapy. RESULTS: Thirty-seven patients were assessable for response. Twenty-two had measurable disease at baseline; response was not assessable in six of these patients. Overall response was 45% (10 of 22 patients; 95% confidence interval [CI], 24% to 68%), and response was 63% (10 of 16) in assessable patients. Twenty-six patients had a > or = 50% decrease from their baseline prostate-specific antigen levels during therapy, for a response rate of 65% (95% CI, 48% to 79%) by this criterion. Median duration of response was 3.2 months, with an estimated median survival of 12.8 months. Major toxicities of therapy were leukopenia (eight patients had > or = grade 4 leukopenia) and anemia. Hematologic toxicity seemed to be associated with liver metastases. Serial measurements in 24 patients using the Functional Assessment of Cancer Therapy-Prostate (FACT-P) showed no significant change in quality of life (QOL) as a result of therapy. CONCLUSION: The combination of IV paclitaxel, oral estramustine, and oral etoposide is active in patients with advanced prostate cancer. The regimen is tolerable and does not have a significant impact on QOL as measured by the FACT-P in a limited sample of patients.     

A phase II trial of CI-958 in patients with hormone-refractory prostate cancer

Purpose: To assess the antitumor activity of the benzothiopyranoindazole CI-958 {5-[(2-aminomethyl)amino]-2-[2-(diethylamino)ethyl]-2H-[l]benzothi- opyrano[4,3,2-cd]-indazol-8-ol trihydrochloride} in hormone-resistant prostate carcinoma, using an intravenous dose of 700 mg/m² every 3 weeks. Patients and methods: Patients eligible for this study had advanced prostate carcinoma that had failed hormonal treatment. Changes in an initially elevated prostate-specific antigen (PSA) level and regression of objectively measurable disease were used as response criteria. Results: All 33 patients enrolled were evaluated. Of 30 with elevated PSA levels, 6 had a >50% decline maintained for >30 days; response durations ranged from 105 to 623 days. Eleven patients had objectively measurable disease; two had partial responses (lasting 316 and 461 days) consisting of shrinkage of retroperitoneal nodes and of masses surrounding the rectum and bladder. The survival of all responding patients ranged from 366 days to 709 days and the median survival of all patients was 12 months (range 1–23 + months). Neutropenia was common, but thrombocytopenia was not. Nonhematologic side effects included nausea, vomiting, anorexia, asthenia, and chills, but were usually mild. The drug caused phlebitis when given into peripheral veins and central venous administration is recommended. No consistent reductions in cardiac function were documented by sequential assessment of left ventricular ejection fractions. Conclusions: CI-958 has modest but definite antitumor activity in hormone-resistant prostate carcinoma. Its toxicities include neutropenia, nausea, vomiting, anorexia, asthenia, chills and phlebitis. Received: 22 January 1999 / Accepted: 8 April 1999     

Phase II study of vinorelbine with low dose prednisone in the treatment of hormone-refractory metastatic prostate cancer

A phase II trial of vinorelbine and low dose prednisone in hormone-refractory metastatic prostate cancer was conducted in order to investigate its safety, efficacy and impact on quality of life. Vinorelbine was administered at the dose of 25 mg/m(2) i.v. weekly for 12 weeks and then biweekly, along with 10 mg of daily oral prednisone until time of progression. Fourteen patients, median age of 74 years, were treated. The treatment was generally well tolerated with leukopenia and anemia as the major side effects. One patient achieved partial remission and eleven remained with stable disease. One of the eleven patients with stable disease had a dramatic PSA response from 1000 to 236 ng/ml; seven of these progressed after week twelve when vinorelbine was given biweekly. PSA response occurred in 5 of 14 patients. The median time to progression was 28 weeks and the median survival was 17 months. Nine out of the 14 accrued patients were evaluable for quality of life assessment. Five of them improved, three remained unchanged and two had a slight worsening. Four patients had improvement in pain control and fatigue. Our preliminary data suggest that the combination of vinorelbine/prednisone has modest activity in metastatic prostate cancer with a very favorable toxicity profile and is very well tolerated in this group of elderly patients.     

State-of-the-art treatment of metastatic hormone-refractory prostate cancer

Initial therapy for advanced prostate cancer includes androgen ablation by surgical or medical castration. Still, nearly all men with metastases will progress to hormone-refractory prostate cancer (HRPC). Current U.S. Food and Drug Administration-approved agents for the treatment of HRPC include mitoxantrone and estramustine, although the vinca alkaloids and the taxanes have shown promising activity in single-agent phase II trials. Combinations of these agents induce a biochemical response in greater than 50% of patients, but the median duration of response is approximately 6 months. Overall survival of patients treated with these combinations is approximately 18-24 months. Studies are ongoing to develop novel therapies that target specific molecular pathways or mechanisms of chemotherapy resistance. Novel agents under development include growth factor receptor inhibitors, antisense oligonucleotides, bisphosphonates, and cell differentiating agents. Evaluation and incorporation of these agents into existing treatment regimens will guide us in the development of more active regimens in the treatment of HRPC.     

A Phase II study of high-dose tamoxifen in patients with hormone-refractory prostate cancer.

Micromolar concentrations of tamoxifen inhibit the activity of protein kinase C and were recently shown to inhibit prostate cancer cell growth in preclinical studies. Because micromolar concentrations can be attained with high-dose therapy, the clinical activity of high-dose tamoxifen was evaluated in patients with metastatic adenocarcinoma of the prostate. Between December 1993 and February 1997, 30 patients with hormone-refractory metastatic adenocarcinoma of the prostate were continuously administered tamoxifen at 160 mg/m2/day. Therapy was continued until disease progression. All study patients had failed prior treatment with combined androgen blockade, had castrate levels of testosterone, and were heavily pretreated, having received a median of three prior regimens. The average steady-state plasma concentration of tamoxifen was 2.96+/-1.32 microM (mean +/- SD). Grade 3 neurotoxicity was observed in 29% of patients and was rapidly reversible and readily managed with dose modification. Otherwise, grade 3 toxicities were rare. One partial response (80% decline in prostate-specific antigen) was observed (3.3%), whereas disease stabilization was observed in six patients (20%), for a combined partial response/stable disease response rate of 23%. Median time to progression was 2.1 months, and median survival time was 10.5 months. High-dose tamoxifen therapy was well tolerated and associated with micromolar concentrations of tamoxifen in human plasma, and it demonstrated activity, albeit limited, in a heavily pretreated patient cohort with hormone-refractory prostate cancer. These findings suggest that further investigation of the role of protein kinase C modulation in prostate cancer is warranted.     

Liposomal doxorubicin for the treatment of hormone-refractory prostate cancer

There is a pressing need for new agents to treat hormone-refractory prostate cancer (HRPC). Doxorubicin has shown modest activity in this setting, but its use is limited by its toxicities. Liposomal encapsulation of doxorubicin appears to promote enhanced tumor accumulation in some tumor types, and toxicity appears to be reduced. A phase II trial of liposomal doxorubicin was therefore conducted in patients with HRPC. Fourteen patients with progressive HRPC were treated. For the first dose only, patients were randomized to receive either doxorubicin 50 mg/m2 or liposomal doxorubicin 50 mg/m2 in order to evaluate exploratory pharmacokinetics. For all subsequent cycles, all patients received liposomal doxorubicin 50 mg/m2. Response to therapy was assessed with serial measurements of serum prostate-specific antigen (PSA) and sequential imaging studies. All 14 patients were evaluable for response and toxicity. Two patients (14%) had declines in serum PSA of > or = 50%. The first patient had a baseline PSA of 34.7 ng/mL and a nadir of 17.0 ng/mL. The second patient had a baseline PSA of 5580.0 ng/mL and a nadir of 200.7 ng/mL. The latter of these 2 patients had an unambiguous improvement in bone scan and a reduction in pain. Treatment was well tolerated overall. One patient was removed from treatment after the development of a grade 3 infusion reaction with the first cycle of liposomal doxorubicin. Neutropenia was the most common toxicity; in only 1 case was it grade 3, and no cases of grade 4 were seen. Doxorubicin plasma concentrations were best fit by a linear, two-compartment model. Liposomal doxorubicin plasma concentrations were best fit by a linear, one-compartment model. Treatment with liposomal doxorubicin was well tolerated overall. While monotherapy with liposomal doxorubicin has only modest activity in the treatment of HRPC, it may be of interest to study this agent as part of combination chemotherapy.     

Achieving treatment goals for hormone-refractory prostate cancer with chemotherapy

The belief that hormone-refractory prostate cancer (HRPC) is a chemotherapy-resistant disease has been effectively refuted by the results of two recent randomized phase III trials. The TAX327 trial compared weekly docetaxel, every-3-weeks (Q3W) docetaxel, and Q3W mitoxantrone plus prednisone in 1,006 patients with HRPC, and results demonstrated that survival was significantly longer with a docetaxel-based regimen than with mitoxantrone. That trial demonstrated that only Q3W docetaxel was significantly superior to mitoxantrone with respect to overall survival. Quality of life was also superior in the docetaxel groups. In the Southwest Oncology Group (SWOG) 9916 trial, 674 men with progressive HRPC were randomized to 3-week cycles of docetaxel plus estramustine or mitoxantrone plus prednisone. Overall and disease-free survival times were significantly longer in the docetaxel arm. Collectively, the results of these trials demonstrate that survival can be significantly improved with chemotherapy in patients with HRPC to an extent that is comparable with the survival benefits seen in other cancers considered sensitive to chemotherapy such as breast cancer. Among various research tasks in HRPC is the definition of potential surrogate end points for survival, which will facilitate the conduct of pivotal trials. Prostate-specific antigen (PSA) response rate and changes in PSA constructs (i.e., PSA doubling time and PSA velocity) are promising potential surrogate end points for future trials and are being actively evaluated at the present time. Until there is clear demonstration of a surrogate role for these alternative end points, survival remains the appropriate end point for phase III trials in HRPC. There is a need for safe and effective second- and third-line regimens for patients progressing after docetaxel, and these patients should enter clinical trials designed for this population. Mitoxantrone, vinorelbine, the platinum analogue satraplatin, and epothilone are among compounds that require careful testing in this setting. The addition of targeted therapies, such as the endothelin receptor antagonist, atrasentan, and angiogenesis inhibitors, such as thalidomide and bevacizumab, to docetaxel-based therapy is being evaluated. High-dose calcitriol may also be an effective addition to docetaxel. The extensive effort devoted to the evaluation of chemotherapy and other systemic modalities of treatment of HRPC is likely to yield additional clinical benefit for patients, making HRPC a more manageable, less lethal, and less debilitating disease.     

Phase II randomized trial of weekly paclitaxel with or without estramustine phosphate in progressive, metastatic, hormone-refractory prostate cancer

This study was conducted to determine the similarity of response rates and safety produced by weekly paclitaxel with or without oral estramustine in patients with metastatic hormone-refractory prostate cancer. Between December 1998 and December 1999, 163 patients were randomized to receive 28-day cycles of paclitaxel 100 mg/m2 on days 2, 9, and 16 plus estramustine 280 mg orally 3 times a day on days 1-3, 8-10, and 15-17, or to receive paclitaxel 100 mg/m2 alone on days 1, 8, and 15. Objective response was defined as a > oe = 50% decrease in prostate-specific antigen (PSA) maintained for 4 weeks with stable or improved performance status. Response rates included 37 partial responses for paclitaxel/estramustine (47%) and 22 partial responses for paclitaxel (27%; P < 0.01). Median duration of response was 15.1 months for paclitaxel/estramustine and 15.5 months for paclitaxel; median survival was 16.1 months and 13.1 months, respectively (P = 0.049). Common toxicities for both treatments included neutropenia, gastrointestinal events, neuropathy, and asthenia. Thromboembolic events were more frequent in the paclitaxel/estramustine arm (no prophylactic anticoagulants). The rate of PSA decline for paclitaxel/estramustine was almost 2 times that of paclitaxel (47% vs. 27%), with acceptable toxicity. Multivariate analysis of prognostic factors affecting survival was not significant for treatment arm (P = 0.08). Although the incidence of thromboembolic events appeared to be increased in the paclitaxel/ estramustine arm, the addition of estramustine was responsible for a 20% increase in the rate of PSA decline. Neither treatment arm had significant impact on quality of life as measured by the Functional Assessment of Cancer Therapy-Prostate quality of life questionnaire. This study produced encouraging data; further studies of paclitaxel/ estramustine are recommended.