Serum prostate-specific antigen decline as a marker of clinical outcome in hormone-refractory prostate cancer patients: association with progression-free survival, pain end points, and survival.

PURPOSE: Validated end points are lacking for clinical trials in hormone-refractory prostate cancer (HRPC). Controversy remains regarding the utility of a posttreatment decline of prostate-specific antigen (PSA). The purpose of this study was to determine whether posttreatment declines in PSA were associated with clinical measures of improvement in a randomized phase III trial of suramin plus hydrocortisone versus placebo plus hydrocortisone. PATIENTS AND METHODS: A total of 460 HRPC patients were randomized to receive suramin plus hydrocortisone (n = 229) or placebo plus hydrocortisone (n = 231). All patients had symptomatic, metastatic HRPC requiring opioid analgesics. Clinical end points evaluated included overall survival, objective progression-free survival (OPFS), and time to pain progression (TTPP). An evaluation of overall survival, OPFS, and TTPP as a function of a PSA decline of > or = 50%, lasting at least 28 days, was undertaken by using a landmark analysis at 6, 9, and 12 weeks. A multivariate analysis of the impact of PSA decline was performed on these clinical end points. RESULTS: A decline in PSA of > or = 50% lasting > or = 28 days was significantly associated with a prolonged median overall survival, OPFS, and TTPP, both in the entire group and the suramin plus hydrocortisone group at all three landmarks in both univariate and multivariate analysis. CONCLUSION: In this prospective, randomized trial of suramin plus hydrocortisone versus placebo plus hydrocortisone, a posttherapy decline in PSA of > or = 50%, lasting 28 days, was associated with prolonged median overall survival, improved median progression-free survival, and median TTPP. This analysis suggests that a posttreatment decline in PSA may be a reasonable intermediate end point in HRPC trials and calls into question the clinical utility of preclinical assays evaluating the in vitro effect of given agents on PSA secretion.     

A retrospective evaluation of second-line chemotherapy response in hormone-refractory prostate carcinoma: second line taxane-based therapy after first-line epothilone-B analog ixabepilone (BMS-247550) therapy

BACKGROUND: Epothilones and taxanes interfere with microtubule function. Ixabepilone, which is an epothilone-B analog, has activity against taxane-resistant cell lines and as first-line therapy for men with hormone-refractory prostate carcinoma (HRPC). Clinical cross-resistance of ixabepilone and taxanes in HRPC is unknown. METHODS: Records were evaluated retrospectively from patients with HRPC who were treated on a randomized Phase II trial of ixabepilone with or without estramustine and who subsequently received taxane chemotherapy. Posttherapy declines in prostate-specific antigen (PSA) levels and time to PSA progression were defined by consensus criteria. The median survival was evaluated by using the Kaplan-Meier method. RESULTS: Forty-nine patients who received ixabepilone with estramustine (28 patients) or without estramustine (21 patients) subsequently received second-line taxane therapy. Second-line PSA declines > or = 50% were achieved by 51% of patients (95% confidence interval [95% CI], 33-66%). Second-line PSA declines > or = 50% were achieved by 61% of patients (95% CI, 42-78%) who achieved a first-line PSA decline > or = 50% with ixabepilone, compared with 33% of patients (95% CI, 13-59%) who did not (P = 0.08). Patients who discontinued first-line ixabepilone treatment for disease progression were less likely to achieve a PSA decline > or = 50% in response to second-line, taxane-based therapy compared with patients who discontinued for toxicity or patient preference (36% vs. 71%; P = 0.01). CONCLUSIONS: Second-line taxane chemotherapy after ixabepilone resulted in a substantial frequency of PSA declines. Although patients with ixabepilone-refractory disease were less likely to respond to second-line taxane chemotherapy, 36% did achieve a PSA response. These findings were consistent with incomplete clinical cross-resistance between the taxanes and the epothilones.     

Epirubicin combined with estramustine phosphate in hormone-resistant prostate cancer: a phase II study.

Twenty-four assessable patients with hormone-resistant prostate cancer (HRPC) were to receive daily doses of oral estramustine phosphate (EMP), 10 mg kg(-1), and intravenous epirubicin (EPR) infusions, 100 mg m(-2), every third week up to a cumulative dose of 500 mg m(-2). Biochemical response [> or = 50% reduction in pretreatment serum prostate-specific antigen (PSA) after three cycles of > or = 3 weeks'' duration] was demonstrated in 13 of 24 patients included (54%). No objective response (WHO criteria) was observed, although seven of nine evaluable patients achieved a > or = 50% serum PSA reduction. Subjective improvement (pain score, performance status) occurred in 7 of 24 patients, whereas nine patients progressed subjectively. There was no correlation between subjective and biochemical response. Biochemical progression (> or = 50% increase of nadir PSA) occurred after a median of 12 weeks. All but two patients were alive after a median follow-up time of 8.7 months for surviving patients (range 3.3-13.2). Eight patients experienced grade 3/4 leucopenia, with no indication of cumulative myelosuppression. Cardiovascular toxicity was experienced by four patients. Two patients developed angioedema twice, in one patient requiring hospitalization at the intensive ward. Based on this limited series, the combination of EPR and EMP in patients with HRPC is tolerable and appears to be effective in terms of significant PSA reduction. The results warrant further investigations of the two drugs and, in particular, of the clinical significance of > or = 50% PSA decrease in patients with HRPC.     

Is it reasonable to consider second-line chemotherapy in patients with hormone-refractory prostate cancer?

At present, no consensus exists regarding the use of second-line chemotherapy in patients with hormone-refractory prostate cancer (HRPC). A total of 23 patients with evidence of disease progression during or after first-line chemotherapy (epirubicin, etoposide, and dexamethasone) were included in this study. Two second-line treatments were administered throughout the study period (2000-2004) with 15/23 patients receiving carboplatin AUC 3 on day 1 and vinblastine 5 mg/m2 on day 1 of a 21-day cycle and 8/23 patients treated with docetaxel 50 mg/m2 on day 1 of a 21-day cycle. The latter regimen has been used since 2003. The prostate-specific antigen (PSA) level decreased by > or =50% in 3 of 23 patients, corresponding to an overall PSA response rate of 13% (95% confidence interval, 3-34%). The median time to biochemical progression was 9, 24 and 33 weeks, respectively. The median overall survival was 39 weeks (range, 15-73 weeks) with no difference between the two chemotherapy groups (p=0.08). A significant reduction of analgesic use was observed in 2 of 10 patients (20%) who required analgesics for cancer pain upon study entry. The major toxicity was grade 3 thrombocytopenia in 2 of 23 patients (9%). Both second-line treatments, a combination of carboplatin and vinblastine and a monotherapy with docetaxel, showed modest activity at subtoxic doses in patients with HRPC.     

Ixabepilone (epothilone B analogue BMS-247550) is active in chemotherapy-naive patients with hormone-refractory prostate cancer: a Southwest Oncology Group trial S0111.

PURPOSE: The epothilones are a new class of tubulin-polymerizing agents with activity in taxane-sensitive and resistant tumor models. We evaluated ixabepilone (BMS-247550) in patients with metastatic hormone-refractory prostate cancer (HRPC). METHODS: Eligible patients had chemotherapy-naive metastatic HRPC, a Zubrod performance status of 0 to 2, and adequate organ function. All patients received BMS-247550 at 40 mg/m2 over 3 hours every 3 weeks. The primary end point was proportion of patients achieving a prostate-specific antigen (PSA) response. RESULTS: Forty-eight patients with metastatic HRPC were registered. Forty-two patients were eligible, with a median age of 73 years and a median PSA level of 111 ng/mL; 78% had bone-only or bone and soft tissue metastases, and 88% had objective radiologic disease progression at registration. Grade 3 and 4 adverse events (AEs) occurred in 16 and three patients, respectively. All grade 4 toxicities were neutropenia or leukopenia. The most frequent grade 3 AEs were neuropathy (eight patients), hematologic toxicity (seven patients), flu-like symptoms, and infection (five patients each). There were no grade 3/4 thrombocytopenia or grade 5 AEs. There were 14 confirmed PSA responses (33%; 95% CI, 20% to 50%); 72% of PSA responders had declines greater than 80%, and two patients achieved an undetectable PSA. The estimated median progression-free survival is 6 months (95% CI, 4 to 8 months), and the median survival is 18 months (95% CI, 13 to 24 months). CONCLUSION: Ixabepilone has demonstrated activity in patients with chemotherapy-naive metastatic HRPC. Major toxicities were neutropenia and neuropathy. Further testing to define its activity relative to standard therapy is warranted.     

Activity of second-line chemotherapy in docetaxel-refractory hormone-refractory prostate cancer patients : randomized phase 2 study of ixabepilone or mitoxantrone and prednisone

BACKGROUND: This randomized, noncomparative, multicenter, clinical trial evaluated ixabepilone or mitoxantrone/prednisone (MP) as second-line chemotherapy for taxane-refractory, hormone-refractory, prostate cancer (HRPC). METHODS: Patients with HRPC that progressed during or within 60 days of cessation of taxane chemotherapy were randomly selected with equal probability to ixabepilone 35 mg/m(2) intravenously every 3 weeks, or mitoxantrone 14 mg/m(2) intravenously every 3 weeks and prednisone 5 mg orally twice daily. Treatment continued until progression or toxicity; crossover was allowed. RESULTS: Forty-one patients were accrued to each arm of the study. The median number of cycles administered for each arm was 3. Median survival from protocol entry was 10.4 months with ixabepilone and 9.8 months with MP. Prostate-specific antigen (PSA) declines of >or=50% were observed in 17% of ixabepilone (95% CI, 7-32) and 20% of second-line MP patients (95% CI, 9-35). Partial responses were observed in 1 of 24 ixabepilone and in 2 of 21 MP patients with evaluable measurable disease. Median duration of second-line ixabepilone and MP treatment was 2.2 months and 2.3 months, respectively. For third-line crossover treatment, PSA declines of >or=50% were observed in 3 of 27 ixabepilone-treated and 4 of 15 MP-treated patients. Prior taxane response was associated with an increased likelihood of second-line ixabepilone or MP response. Low baseline lactate dehydrogenase and absence of visceral metastases independently predicted improved survival. The most common grade 3/4 toxicity associated with second-line treatment was neutropenia (54% of ixabepilone patients and 63% of MP patients). CONCLUSIONS: Ixabepilone and MP had modest activity as second-line chemotherapy for docetaxel-refractory HRPC. The median survival for the entire cohort treated in this study was 9.8 months.     

A phase I study of estramustine, weekly docetaxel, and carboplatin chemotherapy in patients with hormone-refractory prostate cancer.

PURPOSE: To define the maximal tolerated dose, safety, and efficacy of docetaxel, carboplatin, and estramustine in patients with hormone-refractory prostate cancer (HRPC). METHODS: Patients with HRPC received docetaxel for 3 weeks, followed by a rest week. Docetaxel (20, 25, 30, 36, or 43 mg/m2) was given on days 2, 9, and 16 of a 28-day cycle. Patients also received estramustine (140 mg p.o. three times daily on days 1-5, 8-12, and 15-19) and carboplatin [area under the curve, AUC (5) or (6) on day 2]. RESULTS: Thirty patients were treated. Five patients received carboplatin [AUC (6)] but experienced delayed thrombocytopenia. After a protocol amendment, 25 subsequent patients received carboplatin [AUC (5)]. Median age was 64 years. Median prostate-specific antigen (PSA) was 117 ng/mL. Fifty-three percent received prior ketoconazole and 10% had mitoxantrone. No dose-limiting toxicities were noted. Although maximal tolerated dose was not reached, docetaxel dose escalation was stopped at 43 mg/m2. Significant myelosuppression was not seen until the highest dose level, when seven and four patients experienced grade 3 and 4 toxicities, respectively. Among all patients, PSA declines of > or =50% occurred in 63%. At the recommended phase II dose, PSA declines of > or =50% occurred in 75% (95% confidence interval, 43-95). Four of 14 (29%) patients with measurable disease had partial responses. Median survival was 14.6 months. CONCLUSIONS: Estramustine, docetaxel, and carboplatin are well tolerated and active in HRPC. Myelosuppression is the primary toxicity. The recommended phase II dose of docetaxel is 43 mg/m2 combined with estramustine and carboplatin. PSA declines were seen at every dose level.     

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.     

Biweekly administration of low-dose docetaxel in hormone-resistant prostate cancer: pilot study of an effective subtoxic therapy

Taxane-based chemotherapy has shown activity but also toxicity when administered at standard doses in patients with hormone-resistant prostate cancer (HRPC). In this pilot study, we investigated biweekly low-dose docetaxel in patients with HRPC as a convenient regimen with low toxicity. Sixteen patients with metastatic HRPC entered the study. Median age was 73 years, median performance status (PS) was 2, and median Gleason score was 9. All patients had undergone and failed combined androgen-blockade therapy (luteinizing hormone-releasing hormone analogue plus antiandrogen) for their metastatic disease; 3 had also been treated with mitoxantrone. Treatment consisted of docetaxel 30 mg/m2 administered every 2 weeks. Prostate-specific antigen (PSA) response, characterized by a 50% decrease of PSA level confirmed 4 weeks later, was the primary endpoint. Durations of PSA response and toxicity assessment were secondary endpoints. A total of 136 biweekly docetaxel doses were administered, with a median of 8.5 doses per patient (range, 2-24). Six patients (38%; 95% confidence interval, 25%-43%) fulfilled the criteria of PSA response. Median duration of PSA response was 4.5 months (range, 3-12). Toxicity was negligible: myelotoxicity was practically absent, whereas 3 patients developed grade 1 alopecia and 1 patient developed dacryorrhea. We conclude that our study provides evidence that biweekly docetaxel at 30 mg/m2 can be considered an effective nontoxic therapeutic option for patients with HRPC. Confirmation of these preliminary data in larger-scale trials is justified     

Clinical outcome of patients with docetaxel-resistant hormone-refractory prostate cancer treated with second-line cyclophosphamide-based metronomic chemotherapy

For patients with docetaxel-resistant hormone-refractory prostate cancer (HRPC) no standard chemotherapeutic treatment exists. In this study, we evaluate the efficacy of cyclophosphamide (CP)-based metronomic chemotherapy in this patient population. Patients with metastatic HRPC with disease progression under docetaxel-based chemotherapy were eligible. The primary endpoint was prostate-specific antigen (PSA) response. Secondary endpoints were survival and toxicity. Low-dose CP (50 mg/d) and dexamethasone (1 mg/d) were administered orally in a metronomic manner. Treatment was continued until disease progression or intolerable side effects occurred. Seventeen patients were enrolled in this study. The median follow-up was 12 weeks (range: 4–60). Median age was 68 years (range: 42–85). Median PSA at study entry was 134 ng/ml (range: 46.0–6554). Nine patients had a PSA response (median 44.4%), four patients ≥50% and five patients <50%. Eight patients had a PSA progression. Overall survival was 24 months. Five patients reported a decrease in bone pain after 4 weeks' treatment. No grade 3 and 4 toxicities were noted. In this study, low-dose metronomically administered CP demonstrated efficacy as a second-line treatment in patients with docetaxel-resistant HRPC. The treatment was well tolerated and almost without toxicity. Further advantages of low-dose CP were its convenient oral administration, dosing schedule, low cost, and low-toxicity profile. These attributes in combination with immunoregulatory and antiangiogenic potentials make CP also a prime candidate for combination with other treatment regimens.     

Treatment of androgen-independent, hormone-refractory prostate cancer with docetaxel in Japanese patients

Background Although patients with prostate cancer with metastatic lesions initially respond to androgen ablation therapy, most patients ultimately develop a hormone-refractory state. Effective treatment for men with hormone-refractory prostate cancer (HRPC) has not been established. We performed a clinical study of docetaxel in HRPC patients, and evaluated its efficacy.Methods Nine patients with HRPC were administered 55 mg/m² docetaxel, every 3 weeks, simultaneously with hormonal therapy, with a luteinizing hormone-releasing hormone analog, and daily oral dexamethasone. Change in serum prostate-specific antigen (PSA) was determined as the primary endpoint.Results The mean age of the patients was 64 years (range, 49 to 76 years). Median follow-up time was 8.5 months (range, 5.3 to 16.7 months). In eight patients whose pretreatment serum PSA was elevated, six patients (75.0%) had a PSA decline of more than 50%, and four (50.0%) had a PSA decline of more than 75%. Median time to progression for all patients was 7.9 months (range, 0.0 to 11.6 months; 95% confidence interval [CI], 0.0 to 26.3). The median overall survival was 8.5 months (range, 5.3 to 16.7 months; 95% CI, 8.1 to 13.8). Four of six patients (66.7%) with pain before treatment obtained pain relief and were able to discontinue analgesic agents. This regimen was well tolerated. Grade 3 or 4 neutropenia or leukocytopenia without fever was seen in three patients (33.3%). Only one patient required administration of granulocyte-colony stimulating factor because of neutropenia. No other grade 3 or 4 toxicity was observed.Conclusion Docetaxel was an active agent in Japanese HRPC patients, and was well tolerated in this population. To establish its efficacy and safety in Japanese HRPC patients, a large-scale study in Japan is warranted.     

Phase I trial of patient-oriented vaccination in HLA-A2-positive patients with metastatic hormone-refractory prostate cancer

To evaluate the safety and toxicity of peptide vaccination for patients with metastatic hormone-refractory prostate cancer (HRPC) based on pre-existing peptide-specific cytotoxic T-lymphocyte (CTL) precursors in the circulation, 10 patients positive for human leukocyte antigen (HLA)-A2 with metastatic HRPC were enrolled in a phase I study. Peptide-specific CTL-precursors reactive to 16 kinds of vaccine candidates in the pre-vaccination peripheral blood mononuclear cells (PBMCs) were measured, and patients were followed by vaccination with only positive peptides (up to 4 kinds of peptides). Serum prostate-specific antigen (PSA) levels were monitored regularly. The peptide vaccination was safe and well tolerated with no major adverse effects. The most common toxicities were dermatologic reactions at the injection site. Increased CTL response to peptides was observed in 4 of 10 patients. Anti-peptide IgG was also detected in post-vaccination sera of 7 of 10 patients. One patient showed the disappearance of a pelvic bone metastasis after five vaccinations. Three patients showed a decrease of serum PSA level from the baseline after the vaccination, but no patients showed a serum PSA level decrease of ∼50%. The median survival duration of study patients was 22 months with follow-up from 3 to 27 months. We consider that the increase in cellular and humoral immune responses, and decrease in PSA level in some patients justify further development of peptide vaccination for metastatic HRPC patients. (Cancer Sci 2004; 95: 77–84)     

Weekly 1-hour infusion of paclitaxel. Clinical feasibility and efficacy in patients with hormone-refractory prostate carcinoma

BACKGROUND: Preclinically, paclitaxel given according to an intense bolus schedule has significant antitumor activity against human prostate carcinoma cell lines in SCID mice. The authors evaluated the feasibility and efficacy of weekly 1-hour infusion of paclitaxel in patients with metastatic hormone-refractory prostate carcinoma (HRPC). METHODS: A total of 18 patients with progressive metastatic HRPC were enrolled. Patients had to have no prior chemotherapy. Paclitaxel was infused weekly at a dose of 150 mg/m(2) over 1 hour for 6 weeks every 8 weeks. RESULTS: Eighteen patients with a median age of 68.5 years and a median prostate specific antigen (PSA) level of 82 ng/mL (range, 2.17-3196 ng/mL) were enrolled. The median number of prior hormone treatments was 2, and 12 patients on antiandrogens completed antiandrogen withdrawal. Ten of eighteen patients had bone-only metastasis and eight had metastasis to bone with lymph node and/or visceral metastasis. Seventeen patients received a total of 31 cycles (157 courses) and 1 patient refused chemotherapy. All patients were included in response evaluation. Of the 8 [corrected] patients with measurable disease, 4 achieved a major response, with 1 complete response (in the lung) and 3 partial responses (1 in the liver and 2 in the lymph nodes). Seven of eighteen patients (39%) had a PSA decline of >/=50%. The major high grade toxicity was peripheral neuropathy, with 6 patients (35%) developing Grade 3 toxicity. CONCLUSIONS: Weekly 1-hour paclitaxel has activity in patients with HRPC. The major toxicity is peripheral neuropathy. The minimal myelosuppressive effects make a modified schedule (lower doses on the same schedule or a shorter schedule of the same dose) attractive for future combination chemotherapy trials.     

Weekly administration of docetaxel in patients with hormone-refractory prostate cancer: a pilot study on Japanese patients

OBJECTIVE: Although treatment of hormone-refractory prostate cancer (HRPC) is difficult, a single-agent weekly dose of docetaxel has been reported as a promising regimen for patients with HRPC. The purpose of this study was the investigation of the efficacy of docetaxel for Japanese patients with HRPC. METHODS: Ten patients with HRPC were treated with weekly docetaxel at Tsukuba University Hospital and were evaluated for the responses with respect to serum prostate-specific antigen (PSA), tumor size and survival. Considering the ethnic balance, the dose of docetaxel was reduced to 30 mg/m(2) weekly compared with 36 mg/m(2) in the study reported previously. RESULTS: A biochemical response (>50% decrease in PSA) was observed in five patients (56%; 5/9) with an average time to progression of 4.5 months. In two partial responders as determined by PSA, respective metastatic lesions in bone and soft tissue were also improved. The estimated median survival duration was 6 months. Most of these responses were accompanied by a significant reduction in the requirement for analgesic agents. No severe toxicity of this regimen was observed, except for gastric ulcer in one patient who was excluded from the evaluation. CONCLUSIONS: Weekly administration of docetaxel as a single agent was associated with a high rate of PSA reduction. This treatment is feasible for patients with HRPC, even those who have a poor performance status and extensive prior treatments.     

A phase 2 study of carboplatin plus docetaxel in men with metastatic hormone-refractory prostate cancer who are refractory to docetaxel

BACKGROUND: Prostate cancer is the second leading cause of cancer mortality among men in the U.S. To the authors' knowledge, there is no proven, effective, second-line therapy for docetaxel-refractory disease. Recent data suggest that platinum salts may be effective when combined with taxanes in metastatic hormone-refractory prostate cancer (HRPC). The authors conducted a phase 2 trial of docetaxel plus carboplatin chemotherapy in this disease setting. METHODS: Eligible men had metastatic HRPC that had progressed during or within 45 days after the completion of docetaxel-based chemotherapy. Patients were treated with intravenous docetaxel at a dose of 60 mg/m(2) plus carboplatin at an area under the curve of 4 once every 21 days until they had either disease progression or unacceptable toxicity. RESULTS: Thirty-four patients were enrolled. Therapy was tolerated reasonably well; Grade 3 leukopenia (graded according to the Common Toxicity Criteria grading system) was the most common adverse event (experienced by 56% of patients), but there was only 1 episode of febrile neutropenia reported. Prostate-specific antigen (PSA) declines > or =50% were noted in 18% of patients, and measurable responses were observed in 14%. The median duration of PSA response was 5.7 months. The median progression-free survival was 3 months, and the median overall survival was 12.4 months. Patients were more likely to respond to the combination if they previously had responded to docetaxel. CONCLUSIONS: In men with HRPC who developed progressive disease during or shortly after treatment with docetaxel, the addition of carboplatin resulted in modest additional activity. Taxane-refractory HRPC is an area of unmet need, and the current trial has provided evidence that platinum chemotherapy may be an important therapeutic option.     

Anti—Epidermal Growth Factor Receptor Monoclonal Antibody Cetuximab Plus Doxorubicin in the Treatment of Metastatic Castration-Resistant Prostate Cancer

Purpose

An open-label, dose-escalating phase Ib/IIa trial was performed to establish a safety profile of ascending doses of cetuximab (IMC C225) in combination with doxorubicin administered weekly for 6 treatments in patients with metastatic castration-resistant prostate cancer. The secondary endpoint was to assess the efficacy of cetuximab in combination with doxorubicin as well as to determine the optimal biologic dose and the maximum tolerated dose.

Patients and Methods

Patients in 8 groups received escalating doses of cetuximab 20-300 mg/m² plus doxorubicin 15 or 20 mg/m² given intravenously weekly for 6 consecutive weeks, followed by a 1-week observation period. A treatment response was defined as a > 50% decline in prostate-specific antigen (PSA) or regression of radiographically measurable disease.

Results

Of the 36 treated patients, 25% had grade 2 neutropenia, 39% had leukopenia, and 44% had stomatitis at doxorubicin 20 mg/m². Erythematous skin exanthema was seen in 38% of the patients. There was no significant regression of bone or soft tissue disease, but stable disease was observed in 20 (65%) of the 31 patients with bone disease and 14 (61%) of the 23 patients with lymph node disease. Declines in PSA were modest in the 36 patients, with 1 (2.7%) with an 80% decline from baseline, 2 (5.6%) with > 50% to < 80% declines, and 14 (39%) with progression. Median survival was approximately 18 months.

Conclusion

In a heavily pretreated population of men with metastatic castration-resistant prostate cancer, this study of cetuximab/doxorubicin was associated with minimal PSA declines posttherapy, though median survival was longer compared to historical control groups. Further studies with cetuximab combined with more contemporary chemotherapy for castration-resistant prostate cancer might be warranted.     

Weekly docetaxel and zoledronic acid every 4 weeks in hormone-refractory prostate cancer patients

Objectives: To investigate the safety and efficacy of docetaxel and zoledronic acid in patients with hormone-refractory prostate cancer (HRPC), based on preclinical evidence of synergism between taxanes and bisphosphonates. Methods: Twenty-five patients with advanced HRPC received weekly docetaxel 30 mg/m²: in 18 patients with symptomatic bone metastases and normal renal function, docetaxel was combined with zoledronic acid, 4 mg i.v. every 4 weeks. Premedication consisted of intravenous dexamethasone before docetaxel. No oral steroids were given. Results: Overall, 12 patients (48%) had a PSA response (reduction of 50% or more compared to baseline). A PSA response was achieved in 8/18 patients (44%) receiving concomitant docetaxel and zoledronic acid, and in 7/12 patients (58%) receiving docetaxel and zoledronic acid as first-line therapy. The weekly schedule of docetaxel resulted in a mean received dose intensity of 26 mg/m²/week, or 87% of the planned dose intensity. Toxicity was mild and as expected for docetaxel. The median time to progression was 7 months, and the median overall survival was 16 months. Conclusions: Concomitant treatment with docetaxel and zoledronic acid is safe and has encouraging activity in HRPC. The combination should be evaluated in randomised clinical trials.     

Prospective trial of the herbal supplement PC-SPES in patients with progressive prostate cancer.

PURPOSE: PC-SPES is an herbal supplement for which there are anecdotal reports of anti-prostate cancer activity. This phase II study was undertaken to assess the efficacy and toxicity of PC-SPES in prostate cancer patients. PATIENTS AND METHODS: Thirty-three patients with androgen-dependent prostate cancer (ADPCa) and 37 patients with androgen-independent prostate cancer (AIPCa) were treated with PC-SPES at a dose of nine capsules daily. Clinical outcome was assessed with serial serum prostate-specific androgen (PSA) level measurement and imaging studies. RESULTS: One hundred percent of ADPCa patients experienced a PSA decline of >/= 80%, with a median duration of 57+ weeks. No patient has developed PSA progression. Thirty-one patients (97%) had declines of testosterone to the anorchid range. Two ADPCa patients had positive bone scans; both improved. One patient with a bladder mass measurable on computed tomography scan experienced disappearance of this mass. Nineteen (54%) of 35 AIPCa patients had a PSA decline of >/= 50%, including eight (50%) of 16 patients who had received prior ketoconazole therapy. Median time to PSA progression was 16 weeks (range, 2 to 69+ weeks). Of 25 patients with positive bone scans, two had improvement, seven had stable disease, 11 had progressive disease, and five did not have a repeat bone scan because of PSA progression. Severe toxicities included thromboembolic events (n = 3) and allergic reactions (n = 3). Other frequent toxicities included gynecomastia/gynecodynia, leg cramps, and grade 1 or 2 diarrhea. CONCLUSION: PC-SPES seems to have activity in the treatment of both ADPCa and AIPCa and has acceptable toxicity. Further study is required to determine whether its effects exceed those expected with estrogen therapy.     

Granulocyte macrophage colony-stimulating factor--secreting allogeneic cellular immunotherapy for hormone-refractory prostate cancer.

PURPOSE: This trial evaluated the safety, clinical activity, and immunogenicity of an allogeneic cellular immunotherapy in 55 chemotherapy-na?ve patients with hormone-refractory prostate cancer (HRPC). The immunotherapy, based on the GVAX platform, is a combination of two prostate carcinoma cell lines modified with the granulocyte macrophage colony-stimulating factor (GM-CSF) gene. EXPERIMENTAL DESIGN: HRPC patients with radiologic metastases (n = 34) or rising prostate-specific antigen (PSA) only (n = 21) received a prime dose of 500 million cells and 12 boost doses of either 100 million cells (low dose) or 300 million cells (high dose) biweekly for 6 months. End points were changes in PSA, time to progression, and survival. RESULTS: Median survival was 26.2 months (95% confidence interval, 17, 36) in the radiologic group: 34.9 months (8, 57) after treatment with the high dose (n = 10) of immunotherapy and 24.0 months (11, 35) with the low dose (n = 24). The median time to bone scan progression in the radiologic group was 5.0 months (2.6, 11.6) with the high dose and 2.8 months (2.8, 5.7) with the low dose. In the rising-PSA group (n = 21) receiving the low dose, the median time to bone scan progression was 5.9 months (5.6, not reached), and median survival was 37.5 months (29, 56). No dose-limiting or autoimmune toxicities were seen; the most common adverse events were injection site reaction and fatigue. CONCLUSIONS: These results suggest that this GM-CSF-secreting, allogeneic cellular immunotherapy is well tolerated and may have clinical activity in patients with metastatic HRPC. Phase 3 trials to confirm these results are under way.     

Experience with docetaxel in hormone-refractory prostate cancer (HRPC) at three Australian cancer centers: A retrospective study

Background: Hormone‐refractory prostate cancer (HRPC) is associated with a poor prognosis and has historically been considered relatively chemoresistant. Emerging data demonstrate clinical benefit with the use of docetaxel in HRPC, culminating in two recent published phase III studies demonstrating survival benefit. Currently, docetaxel is registered but not reimbursed for HRPC in Australia. Aim: To retrospectively review prostate‐specific antigen (PSA) response rate, and survival following the use of docetaxel for metastatic HRPC. Methods: Retrospective audit of the use of docetaxel for HRPC from 1 January 2001 to 1 April 2004 in three medical oncology practices. Demographic data, baseline PSA, ECOG (Eastern Cooperative Oncology Group) Performance Status, sites of disease, number of cycles received and PSA response rates were collected. Results: Thirty five patients (median age, 71 years; range, 50–88) had an ECOG status of 0 (eight), 1 (20) and 2 (seven). The mean duration from initial prostate cancer diagnosis to start of docetaxel was 5.4 years (range, 0.2–13.5 years). The mean baseline PSA doubling time, available for 29/35 patients, was 1.9 months (range, 0.4–4.9). The median number of metastatic sites was 1 (range, 1–4): bone (34 patients), lymph nodes (10), liver (seven) and lung (seven). Twelve patients were chemotherapy naive; 23 had received prior chemotherapy (21/23 received mitoxantrone). Twenty patients received docetaxel three times weekly; 15 were on weekly schedules. Their mean dose density was 23 mg/m²/week. Patients received an average of 3.2 months of treatment (range, 0.2–11.8). There were 170 recorded toxicities, 13 of which were grade 3–4, and two likely treatment‐related deaths (sepsis). Twelve patients (34%) had >50% PSA response (four were chemotherapy naive); of these 12 responders, seven patients had a >75% PSA response (four chemotherapy naive). Median survival from start of docetaxel was 8 months with 37% alive at 12 months and 23% alive at 24 months. Conclusion: Docetaxel is active in HRPC (in both chemotherapy naive and exposed patients) with a predictable toxicity profile. More research is warranted to identify predictors of response and toxicity.