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Background

The use of docetaxel prolongs survival for patients with castrate resistant prostate cancer (CRPC). Inhibition of vascular endothelial growth factor (VEGF) with bevacizumab may further enhance the anti-tumor effect of docetaxel and estramustine in patients with CRPC.

Patients and Methods

This cooperative group trial enrolled men with CRPC. Patients received oral estramustine 280 mg three times per day on days 1-5 of every cycle, with 70 mg/m2 of docetaxel and bevacizumab at 15 mg/kg on day 2, every three weeks. PSA values were monitored every cycle and imaging was performed every 3 cycles. The primary endpoint was progression free survival (PFS) with safety, prostate specific antigen decline, measurable disease response, and overall survival secondary objectives.

Results

Seventy-nine patients were enrolled; 77 received a median of 8 cycles and were evaluable. A 50% PSA decline was observed in 58 patients (75%). Twenty-three of 39 patients with measurable disease had a partial response (59%) The median time of PFS was 8.0 months with an overall median survival of 24 months. Neutropenia without fever (69%), fatigue (25%), thrombosis\emboli (9%) were the most common severe toxicities. Twenty-four of 77 patients were removed from protocol treatment due to disease progression, 35/77 for physician or patient decision and 15 patients secondary to toxicity.

Conclusion

The combination of docetaxel, estramustine and bevacizumab was tolerable but complicated by toxicity. Although progression free survival did not meet the desired endpoint, encouraging anti-tumor activity and overall survival was observed. Further phase III evaluation of the role of bevacizumab in CRPC is ongoing.

The objective of this study was to evaluate the efficacy and safety profile of weekly docetaxel, estramustine and celecoxib in patients with advanced hormone-refractory prostate cancer. Forty-eight patients received 35 mg m−2 of weekly docetaxel for 3 out of every 4 weeks, 280 mg of estramustine twice daily on days 1–3, 8–10, 15–17 and 400 mg of celecoxib twice daily until progression or toxicity. Cycles were repeated every 28 days for at least six cycles. Patients were evaluated for response and toxicity. Patients received a median of four cycles (range: 1–9). On an intention-to-treat analysis, prostate-specific antigen (PSA) was decreased greater than 50% in 28 out of 48 patients (overall response rate: 58%, 95% confidence interval (CI): 44–72) and median duration of PSA response was 8.0 months (95% CI: 6.9–9.0). After a median follow-up of 11.3 months, the median time to progression was 7.1 months and the median overall survival was 19.2 months. The most frequent severe toxicity was asthenia (15% of patients), diarrhoea and stomatitis (8% of patients, each). Grade 3/4 neutropenia was reported in two patients. There was a toxic death during the study due to a gastric perforation. Celecoxib with weekly docetaxel and estramustine is an effective and safe treatment for patients with hormone-refractory prostate cancer, but it does not seem to add any benefit to docetaxel.

Sequential chemotherapy may improve treatment efficacy avoiding the additive toxicity associated with concomitant polichemotherapy in hormone-refractory prostate cancer (HRPC). Forty patients received docetaxel 30 mg m−2 intravenous (i.v.), weekly, plus estramustine 280 mg twice daily for 12 weeks. After 2 weeks rest, patients with a decline or stable PSA were treated with mitoxantrone 12 mg m−2 i.v. every 3 weeks plus prednisone 5 mg twice daily for 12 cycles. Forty patients were assessable for toxicity after docetaxel/estramustine. Main toxicities were grade 3–4 AST/ALT or bilirubin increase in seven patients (17.5%) and deep venous thrombosis (DVT) in four patients (10%). Twenty-seven patients received mitoxantrone/prednisone. Main toxicities included DVT in one patient (3.7%) and congestive heart failure in two patients (7%). Thirty-nine patients were assessable for PSA response. Twenty-nine patients (72.5%; 95% CI 63–82%) obtained a ⩾50% PSA decline with 15 patients (37.5%; 95% CI 20–50%) that demonstrated a ⩾90% decrease. Median progression-free and overall survival were respectively 7.0 (95% CI 5.8–8.2 months) and 19.2 months (95% CI 13.9–24.3 months). In conclusion, although this regimen demonstrated a favourable toxicity profile, sequential administration of mitoxantrone is not able to improve docetaxel activity in patients with HRPC.

Purpose

We investigated the efficacy of ketoconazole and estramustine before chemotherapy for treating patients with progressive castration-resistant prostate cancer (CRPC) after anti-androgen withdrawal syndrome.

Materials and Methods

Eighty-four patients who were diagnosed with CRPC and were treated between 2005 and 2009 were included. Thirty-nine patients were treated with 600 mg of ketoconazole and 10 mg of prednisolone per day (group I), and 45 patients were treated with 560 mg of estramustine per day (group II). The prostate-specific antigen (PSA) response, progression-free survival, and side effects were compared.

Results

The median age of the patients, PSA level, and follow-up period were 72 years, 48.5 ng/ml, and 4 months (range, 1 to 29 months), respectively. The overall PSA response rate was 35.7%, and the PSA response rates were 33.3% for group I and 37.8% for group II (p=0.672). The median progression-free survival times were 8 months (95% confidence interval [CI] 5.9-10.1) overall, 5 months (95% CI 1.6-8.3) in group I, and 8 months (95% CI 5.9-10.0) in group II (p=0.282). The most common complications in groups I and II were nausea and vomiting (51.3%) and anemia (77.8%), respectively. Nausea and vomiting and hepatotoxicity were observed more often in group I, and gynecomastia, neutropenia, and anemia were observed more often in group II. The toxicities of each adverse effect were ≤grade 2.

Conclusions

With a resultant PSA decline and mild adverse effects, both ketoconazole and estramustine are worth consideration as treatment options for progressive CRPC patients after primary hormonal therapy.

Purpose

For patients with metastatic castration-resistant prostatic cancer (mCRPC), docetaxel plus prednisone leads to superior survival and a higher response rate compared with mitoxantrone plus prednisone. We analyzed the efficacy of long-term treatment with ≥10 cycles of docetaxel, and validated the risk group classification in predicting overall survival (OS) in Japanese patients with mCRPC.

Patients and Methods

Fifty-two patients with mCRPC were administered 55 mg/m2 docetaxel and 8 mg dexamethasone, every 3 or 4 weeks, simultaneously with hormonal therapy and daily oral dexamethasone. They were divided into two groups, short-term (9 or fewer cycles) and long-term (10 or more cycles). Four risk factors including the presence of anemia, bone metastases, significant pain and visceral metastases were utilized for the risk group classification.

Results

Fourteen patients (27%) had an elevation of PSA in spite of docetaxel treatment, while 23 patients (44%) had a decline in PSA level, including 9 patients (17%) whose PSA level declined by ≥50%. The median duration of OS after the initiation of this therapy was 11.2 months in the short-term group and 28.5 months in the long-term group. The good risk group showed a significant difference in OS compared with the intermediate and poor risk groups (P<0.001). The median number of cycles of treatment was 14, 4 and 3 for each risk group, respectively (p<0.01).

Conclusions

The present study indicated that ≥10 cycles of this docetaxel therapy can significantly prolong survival in Japanese men with CRPC. This risk group classification for men with mCRPC at the initiation of this chemotherapy is useful.

Prostate cancer (PC) was previously believed to be a chemoresistant disease. In recent years taxane-based chemotherapy has been shown to prolong survival in patients with castration-resistant prostate cancer (CRPC). It remains to be shown, however, which type of chemotherapy provides the most beneficial effect with the least amount of side effects. Seventeen patients with chemonaive CRPC were enrolled in a pilot study evaluating an orally administered chemo-hormonal treatment regimen using a weekly sequential combination called KEES; consisting of ketoconazole in combination with cyclophosphamide or etoposide in combination with estramustine administered on alternate weeks. Prednisone was administered throughout the treatment period. Prostate-specific antigen (PSA) response and acute and chronic toxicities were evaluated. Seventeen patients with CRPC were treated; eleven patients demonstrated a median reduction in PSA of 87% (range 26–99%). Ten (59%) patients responded with a decrease in PSA >50%. Thrombocytopenia and anaemia were the most common side effects. One study fatality was reported, however, it was unclear whether this was treatment related. In conclusion, KEES may be a promising option for patients with CRPC, resulting in a clear reduction in PSA with limited toxicity. Further clinical evaluation of this metronomic chemohormonal combination is underway.

Caspase-cleaved proteins are released from disintegrated apoptotic cells and can be detected in the circulation. We here addressed whether caspase-cleaved cytokeratin 18 (CK18-Asp396) can be used as a serum biomarker for assessment of the clinical efficiency of chemotherapy in hormone-refractory prostate cancer (HRPC). A total of 82 patients with HRPC were evaluated during 751 treatment cycles, either with estramustine (EMP)/vinorelbine or with EMP/docetaxel. The levels of CK18-Asp396 and of total CK18 were measured in patient serum before and during therapy by ELISA. Docetaxel induced significant increases in serum CK18-Asp396 (P<0.0001) and total CK18 (P<0.0002), suggesting induction of apoptosis. Similarly, vinorelbine induced increases in both CK18-Asp396 and CK18 (P<0.001 and 0.011). In contrast, EMP induced increases in total serum CK18 (P<0.0001), but not in CK18-Asp396 (P=0.13). The amplitudes of docetaxel-induced increases were associated with baseline prostate-specific antigen (PSA) and CK18 serum levels in these patients, consistent with tumoral origin of caspase-cleaved fragments. Docetaxel induced significant increases in CK18-Asp396 during second-, third- and fourth-line therapy and induced increased levels of CK18-Asp396 during treatment cycles 1–8. In contrast, vinorelbine induced significant increases only during cycles 1–3. In a subgroup of 32 patients that received EMP/vinorelbine in second line followed by EMP/docetaxel in third line, docetaxel induced stronger increases than vinorelbine (P=0.008). These results show that the CK18-Asp396 serum marker can be used to assess tumour apoptosis in vivo and suggest that the clinical efficiency of docetaxel in HRPC is due to induction of apoptosis during multiple treatment cycles.

Background: Docetaxel is associated with prolonged survival in castration-resistant prostate cancer (CRPC). Platinum compounds have modest but distinct single-agent activity. Carboplatin may have greatest potential for benefit when combined with taxanes. We investigated whether there is a subset of patients with CRPC for whom the efficacy of combination taxane–estramustine–carboplatin (TEC) chemotherapy may be greatest.

Patients and methods: Individual patient data (n = 310) were obtained from seven trials using TEC chemotherapy. Prostate-specific antigen (PSA) response was defined as ≥50% post-therapy decline from baseline. Overall survival was defined from baseline to death from any cause. Logistic and Cox regression were used to investigate heterogeneity in outcome to TEC by patient and disease characteristics. Predicted survival probabilities were calculated from the Halabi Cancer and Leukemia Group B (CALGB) nomogram.

Results: The pooled PSA response proportion was 69% [95% confidence interval (CI) 56% to 80%]. There was no evidence of differential PSA response by disease characteristics. Established prognostic factors were associated with survival. The pooled 12-month survival estimate of 79% (95% CI 71% to 84%) was higher than the median 59% 12-month nomogram-predicted survival.

Conclusions: TEC chemotherapy has significant clinical activity in CRPC. A randomized, controlled trial evaluating the addition of carboplatin to taxane-based chemotherapy is needed to elucidate the value of carboplatin in CRPC.

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.

S-1 is a novel oral fluorouracil prodrug that plays a role in non-small cell lung cancer (NSCLC). Docetaxel (DTX) is one of the standard agents for relapsed NSCLC. We performed a phase I study of DTX plus S-1 combination therapy as second-line treatment for NSCLC to determine the maximum tolerated dose (MTD) and recommended dose (RD). Patients with recurrent NSCLC, aged 20–74 years with an Eastern Cooperative Oncology Group performance status of 0–1 and measurable lesions, were enrolled. The treatment consisted of four dose levels. The patients received DTX (40–60 mg/m2 intravenously on day 1) and S-1 (65–80 mg/m2 orally, daily on days 1–14) for each 21-day cycle. Three to six patients were treated at each dose level with the two drugs, with MTD defined as the dose level at which dose-limiting toxicity (DLT) occurred in 33% of the patients. A total of 17 patients were enrolled. At dose level 4 (DTX, 60 mg/m2; S-1, 80 mg/m2) 3 of 5 patients experienced DLT and this level was regarded as the MTD. Therefore, dose level 3 (DTX, 60 mg/m2; S-1, 65 mg/m2) was selected as the RD for subsequent studies. The DLTs were neutropenia (grade 4) and mucositis (grade 3). The response rate was 5.9% (1 of 17 patients achieved a partial response) and 14 of 17 patients achieved stable disease. This combination regimen showed a tolerable and manageable profile in recurrent NSCLC and therefore warrants further evaluation.

Purpose

High-dose ketoconazole and docetaxel have shown activity as single agents against castration-resistant prostate cancer (CRPC). The goal of this phase I study was to determine the maximum tolerated doses, side effects, and pharmacokinetic interaction of coadministered docetaxel and ketoconazole.

Experimental Design

Patients with metastatic CRPC received weekly docetaxel for 3 of every 4 weeks, plus daily ketoconazole. Pharmacokinetic studies were performed on day 1 (docetaxel alone) and day 16 (after ketoconazole).

Results

The study enrolled 42 patients at 9 different dose levels. The combination regimens investigated included docetaxel weekly for three weeks out of four escalating from 5 to 43 mg/m2, with starting doses of ketoconazole of 600, 800, or 1200 mg/day. Declines in prostate-specific antigen of ≥ 50% were seen in 62% of patients. Of 25 patients with soft tissue disease, 7 (28%) had partial response. Median overall survival was 22.8 months, and was significantly greater in docetaxel-naïve patients than in patients pretreated with docetaxel (36.8 vs. 10.3 months; P = 0.0001). The most frequently observed adverse events were anemia, edema, fatigue, diarrhea, nausea, sensory neuropathy, and elevated liver function tests. The fractional change in docetaxel clearance correlated significantly with ketoconazole exposure (P < 0.01). Concomitant ketoconazole increased docetaxel exposure 2.6-fold with 1200 mg/day, 1.6-fold with 800 mg/day, and 1.3- to 1.5-fold with 600 mg/day.

Conclusions

Results suggest that the combination of weekly docetaxel and ketoconazole has significant antitumor activity in CRPC with manageable toxicities. The extremely long survival in the docetaxel-naïve cohort (36.8 months) warrants additional larger trials of docetaxel with ketoconazole or possibly CYP17A1 inhibitors such as abiraterone.

OBJECTIVES

To determine the activity and tolerability of 100-mg once-daily (QD) dasatinib in patients with metastatic castration-resistance prostate cancer (CRPC). Dasatinib, an oral Src family kinase inhibitor, has demonstrated both preclinical and clinical activity with twice-daily dosing in patients with metastatic CRPC.

METHODS

Chemotherapy-naive men with metastatic CRPC and increasing prostate-specific antigen levels were treated with dasatinib 100 mg QD. The primary measurement was a composite lack of disease progression, according to the Prostate Cancer Working Group 2 criteria, determined every 12 weeks during the study. The other analyses included changes in the prostate-specific antigen level, bone lesions, soft tissue disease, and bone turnover markers (urine N-telopeptide and bone alkaline phosphatase).

RESULTS

The present trial was designed before the publication of the recent Prostate Cancer Working Group 2 criteria; however, the analyses are presented to conform to the updated guidelines. A total of 48 patients received dasatinib. A lack of disease progression was observed in 21 patients (44%) at week 12 and in 8 (17%) at week 24. Urine N-telopeptide was reduced by ≥40% from baseline in 22 (51%) of 43 patients, and bone alkaline phosphatase was decreased in 26 (59%) of 44 patients. Dasatinib was well-tolerated, with only 6 patients (13%) with drug-related grade 3–4 adverse events and 3 (6%) with grade 3 adverse events. The most common treatment-related adverse events (≥20%) were fatigue, nausea, diarrhea, headache, and anorexia.

CONCLUSIONS

Dasatinib 100 mg QD has a favorable safety profile and maintains a similar degree of activity as the previously reported twice-daily dosing schedules. These data support additional study of dasatinib 100 mg QD for metastatic CRPC.

MUC1 is associated with cellular transformation and tumorigenicity and is considered as an important tumor-associated antigen (TAA) for cancer therapy. We previously reported that anti-MUC1 monoclonal antibody C595 (MAb C595) plus docetaxel (DTX) increased efficacy of DTX alone and caused cultured human epithelial ovarian cancer (EOC) cells to undergo apoptosis. To further study the mechanisms of this combination-mediated apoptosis, we investigated the effectiveness of this combination therapy in vivo in an intraperitoneal (i.p.) EOC mouse model. OVCAR-3 cells were implanted intraperitoneally in female athymic nude mice and allowed to grow tumor and ascites. Mice were then treated with single MAb C595, DTX, combination test (MAb C595 and DTX), combination control (negative MAb IgG3 and DTX) or vehicle control i.p for 3 weeks. Treated mice were killed 4 weeks post-treatment. Ascites volume, tumor weight, CA125 levels from ascites and survival of animals were assessed. The expression of MUC1, CD31, Ki-67, TUNEL and apoptotic proteins in tumor xenografts was evaluated by immunohistochemistry. MAb C595 alone inhibited i.p. tumor growth and ascites production in a dose-dependent manner but did not obviously prevent tumor development. However, combination test significantly reduced ascites volume, tumor growth and metastases, CA125 levels in ascites and improved survival of treated mice compared with single agent-treated mice, combination control or vehicle control-treated mice (P<0.05). The data was in a good agreement with that from cultured cells in vitro. The mechanisms behind the observed effects could be through targeting MUC1 antigens, inhibition of tumor angiogenesis, and induction of apoptosis. Our results suggest that this combination approach can effectively reduce tumor burden and ascites, prolong survival of animals through induction of tumor apoptosis and necrosis, and may provide a potential therapy for advanced metastatic EOC.

Docetaxel (Dtx) chemotherapy is the optional treatment in patients with hormone-refractory metastatic prostate cancer, and Dtx-loaded polymeric nanoparticles (NPs) have the potential to induce durable clinical responses. However, alternative formulations are needed to overcome the serious side effects, also due to the adjuvant used, and to improve the clinical efficacy of the drug.

In the present study, two novel biodegradable block-copolymers, poly(lactide-co-caprolactone) (PLA-PCL) and poly(lactide-co-caprolactone-co-glycolide) (PLGA-PCL), were explored for the formulation of Dtx-loaded NPs and compared with PLA- and PLGA-NPs. The nanosystems were prepared by an original nanoprecipitation method, using Pluronic F-127 as surfactant agent, and were characterized in terms of morphology, size distribution, encapsulation efficiency, crystalline structure, and in vitro release. To evaluate the potential anticancer efficacy of a nanoparticulate system, in vitro cytotoxicity studies on human prostate cancer cell line (PC3) were carried out. NPs were found to be of spherical shape with an average diameter in the range of 100 to 200 nm and a unimodal particle size distribution. Dtx was incorporated into the PLGA-PCL NPs with higher (p < 0.05) encapsulation efficiency than that of other polymers. Differential scanning calorimetry suggested that Dtx was molecularly dispersed in the polymeric matrices. In vitro drug release study showed that release profiles of Dtx varied on the bases of characteristics of polymers used for formulation. PLA-PCL and PLGA-PCL drug loaded NPs shared an overlapping release profiles, and are able to release about 90% of drug within 6 h, when compared with PLA- and PLGA-NPs. Moreover, cytotoxicity studies demonstrated advantages of the Dtx-loaded PLGA-PCL NPs over pure Dtx in both time- and concentration-dependent manner. In particular, an increase of 20% of PC3 growth inhibition was determined by PLGA-PCL NPs with respect to free drug after 72 h incubation and at all tested Dtx concentration. In summary, PLGA-PCL copolymer may be considered as an attractive and promising polymeric material for the formulation of Dtx NPs as delivery system for prostate cancer treatment, and can also be pursued as a validated system in a more large context.

Treatment options for castration-resistant prostate cancer (crpc) have evolved since the start of the 2000s, with most of the new effective therapies appearing since 2010. In 2004, docetaxel was the first chemotherapeutic agent to improve survival in crpc, but little else was available once patients recurred. Since 2010, four new options have been shown to improve survival in patients with refractory or recurring disease after docetaxel. In the management of bone metastases, two bone-targeted therapies have been shown to reduce the risk of bone complications, and they are part of the overall management strategy in crpc patients. Therapeutic options before chemotherapy have shown promising results and may soon become available in Canada. The present article reviews the treatment options that have shown to be effective in crpc and also some of the ongoing work in the field.

Resistance to docetaxel (DTX) usually occurs in patients with lung adenocarcinoma. To better elucidate the underlying molecular mechanisms involved in resistance to DTX-based chemotherapy, we established a DTX-resistant lung adenocarcinoma cell line (SPC-A1/DTX). By gene array analysis, the expression of ING4 was found to be significantly downregulated in SPC-A1/DTX cells. Additionally, the decreased expression of the ING4 gene was induced upon DTX treatment of SPC-A1 cells. Overexpression of ING4 reverses DTX or paclitaxel resistance of DTX-resistant lung adenocarcinoma cells (SPC-A1/DTX or A549/Taxol) by inducing apoptosis enhancement and G2/M arrest, and small interfering RNA–mediated ING4 knockdown renders DTX-sensitive lung adenocarcinoma cells more resistant to DTX or paclitaxel. Also, overexpression of ING4 could enhance the in vivo sensitivity of SPC-A1/DTX cells to DTX. The phenotypical changes of SPC-A1/DTX cells induced by overexpression of ING4 might be associated with the decreased ratio of Bcl-2/Bax, which resulted in the activation of caspase-3. The level of ING4 expression in tumors of nonresponding patients was significantly lower than that in those of responders, suggesting that the expression of ING4 was positively correlated with tumor response to DTX. Our results provide the first evidence that ING4 might be essential for DTX resistance in lung adenocarcinoma. Thus, ING4 will be a potential molecular target for overcoming resistance to DTX-based chemotherapies in lung adenocarcinoma.

Background

To test the hypothesis that modulation of Bcl-2 with 13-cis retinoic acid (CRA)/interferon-alpha2b (IFN) with paclitaxel (TAX), or mitoxantrone, estramustine and vinorelbine (MEV) will have clinical activity in men with metastatic castrate-resistant prostate cancer (CRPC).

Methods

70 patients were treated with either MEV (Arm A) in a 3-week cycle or CRA/IFN/TAX with an 8-week cycle (Arm B). Patients were assessed for response, toxicity, quality of life (QOL), and the effect of treatment on Bcl-2 levels in peripheral blood mononuclear cells (PBMC).

Results

The PSA response rates were 50% and 23%, measurable disease response rates (CR+PR) 14% and 15%, and median overall survival 19.4 months and 13.9 months on Arm A and Arm B respectively. Transient grade 4 neutropenia occurred in 18 and 2 patients, and grade 3 to 4 thrombosis in 7 patients and 1 patient in Arm A and Arm B respectively. Patients on Arm B reported a clinically significant decline in QOL between baseline and week 9/10 (.71 s.d.), and a significantly lower level of QOL than Arm A (p = 0.01). As hypothesized, Bcl-2 levels decreased with CRA/IFN therapy only in Arm B (p = 0.03).

Conclusions

Treatment with MEV was well tolerated and demonstrated clinical activity in patients with CRPC. Given the adverse effect of CRA/IFN/TAX on QOL, the study of other novel agents that target Bcl-2 family proteins is warranted. The feasibility of measuring Bcl-2 protein in a cooperative group setting is hypothesis generating and supports further study as a marker for Bcl-2 targeted therapy.

Trial Registration

Clinical Trials Registration number: CDR0000067865

Prostate cancer is the most common cancer in men in United States and the fifth most common cancer in men in Korea. Although the majority of patients with metastatic prostate cancer initially respond to androgen deprivation therapy, almost all patients will eventually progress to develop castration-resistant prostate cancer (CRPC). Treatment options for CRPC remain limited. Prostate cancer was considered unresponsive to chemotherapy until the mid-1990s, when mitoxantrone combined with prednisone was shown to play a role in the palliative treatment of patients with CRPC. In 2004, two large randomized clinical trials demonstrated for the first time a small but significant survival advantage of docetaxel-based chemotherapy compared with mitoxantrone in patients with metastatic CRPC. Recently, cabazitaxel was shown to improve survival in patients with metastatic CRPC who progressed after docetaxel-based chemotherapy. Sipuleucel-T was also demonstrated to improve overall survival in patients with asymptomatic or minimally symptomatic metastatic CRPC. Along with mitoxantrone and docetaxel, cabazitaxel and sipuleucel-T are now approved for use in metastatic CRPC by the US Food and Drug Administration. There have been multiple early-phase clinical trials of various agents for the treatment of CRPC, and some are in phase III development. This review focuses on the key clinical trials of various treatment options of CRPC currently in use and under investigation.

Background

This study was designed to evaluate toxicity and preliminary efficacy of 2 cycles of concomitant standard dose/schedule of 153Sm-lexidronam plus Q 3 weeks schedule escalating doses of docetaxel in metastatic castration-resistant prostate cancer (mCRPC).

Methods

mCRPC patients with progressive bone metastases were treated in 4 cohorts. Docetaxel doses were escalated from 50, 50, 0 mg/m2 (on days 1, 22, 43, per 12-week cycle) to 75, 75, 75 mg/m2. 153Sm-lexidronam was administered on days 2 (Q 12 weeks) at dose of 1 mCi/kg/cycle (maximum of 2 cycles).

Results

Thirteen patients received an average of 3.6 doses of docetaxel (range, 2–6 doses, median 4) and 1.5 doses of 153Sm-lexidronam (range, 1–2, median 2). Toxicity was primarily hematologic. There were total 35 episodes grade 3/4 neutropenia with a median 7 (range 7–14) days to recovery to ≤grade 1. One dose limiting grade 3 thrombocytopenia occurred on cohorts 3 and 4. Eight of 13 (62%) patients had PSA > 50% decrease as best response during the treatment. Median time to bone disease progression was 5.2 months (range 91 days–10 months+); 6/13 (46%) patients had stable/improved bone scans at 6 months and 6/6 (100%) symptomatic patients had improvement in pain.

Conclusions

Concurrent 6-month administration of 4 doses (75 mg/m2) of standard Q 3 weeks schedule of docetaxel with 2 Q 3 months infusions of 1 mCi/Kg 153Sm-lexidronam is feasible with reversible bone marrow suppression, and deserves further testing in mCRPC patients with extensive bone metastasis.

Estraumustine phosphate (EMP), a cytotoxic drug used in the treatment of prostatic carcinoma, has been shown to exert cytotoxic effects on glioma cells in vitro. The drug uptake is assumed to depend on a specific estramustine binding protein (EMBP). One of the main difficulties in achieving cytotoxic effect in malignant brain tumours is believed to be due to the poor penetration of cytotoxic drugs into tumour tissue. In patients with malignant supratentorial brain tumours we have analysed the uptake of EMP metabolites in tumour tissue after oral administration and demonstrated EMBP in the same tissue specimens. Sixteen patients were given 280 mg EMP orally 14 h prior to surgery. Specimens from brain tumour tissue, cystic fluid, and serum were collected during surgery. Using gas chromatography the metabolites of EMP, estramustine (EaM) and estromustine (EoM), were quantified, EMBP was demonstrated by immunohistochemistry. The mean concentrations of EaM and EoM, expressed in ng g-1, were 60.3 and 38.4 in tumour tissue and 3.5 and 56.3 in serum, respectively. An accumulation of EaM in tumour tissue was found with a mean concentration gradient of 16.1 versus serum, while the gradient for EoM was 0.76. EMBP was demonstrated with a high degree of staining in all but one tumour. The high concentrations of EaM and EoM found in malignant brain tumour tissue correspond to potentially cytotoxic levels. The present results as well as the earlier in vitro demonstrated cytotoxic effects on glioma cells strengthen the possibility of a therapeutic effect of EMP in the treatment of malignant brain tumours.

Until recently, patients with castration-resistant prostate cancer (CRPC) had limited therapeutic options once they became refractory to docetaxel chemotherapy, and no treatments improved survival. This changed in June 2010 when the Food and Drug Administration (FDA) approved cabazitaxel as a new option for patients with CRPC whose disease progresses during or after docetaxel treatment. For most of these patients, cabazitaxel will now replace mitoxantrone (a drug that was FDA-approved because of its palliative effects) as the treatment of choice for docetaxel-refractory disease. The approval of cabazitaxel was based primarily on the TROPIC trial, a large (n = 755) randomized Phase III study showing an overall median survival benefit of 2.4 months for men with docetaxel-pretreated metastatic CRPC receiving cabazitaxel (with prednisone) compared to mitoxantrone (with prednisone). Cabazitaxel is a novel tubulin-binding taxane that differs from docetaxel because of its poor affinity for P-glycoprotein (P-gp), an ATP-dependent drug efflux pump. Cancer cells that express P-gp become resistant to taxanes, and the effectiveness of docetaxel can be limited by its high substrate affinity for P-gp. Preclinical and early clinical studies show that cabazitaxel retains activity in docetaxel-resistant tumors, and this was confirmed by the TROPIC study. Common adverse events with cabazitaxel include neutropenia (including febrile neutropenia) and diarrhea, while neuropathy was rarely observed. Thus, the combination of cabazitaxel and prednisone is an important new treatment option for men with docetaxel-refractory metastatic CRPC, but this agent should be administered cautiously and with appropriate monitoring (especially in men at high risk of neutropenic complications).

Purpose

Mitoxantrone plus prednisone and ixabepilone each have modest activity as second-line chemotherapy in docetaxel-refractory castration-resistant prostate cancer (CRPC) patients. Clinical noncrossresistance was previously observed.

Patients and Methods

Metastatic CRPC patients progressing during or after taxane-based chemotherapy enrolled in a phase I multicenter study of ixabepilone and mitoxantrone administered every 21 days along with prednisone. Ixabepilone and mitoxantrone doses were alternately escalated in a standard 3 + 3 design. Patients were evaluated for toxicity and disease response. Dose-limiting toxicities (DLTs) were defined as treatment related, occurring during cycle 1, and included grade 4 prolonged or febrile neutropenia, thrombocytopenia (grade 4 or grade 3 with bleeding), or ≥ grade 3 nonhematologic toxicity.

Results

Thirty-six patients were treated; 59% of patients experienced grade 3/4 neutropenia. DLTs included grade 3 diarrhea (n = 1), prolonged grade 4 neutropenia (n = 4), and grade 5 neutropenic infection (n = 1). Due to prolonged neutropenia, the highest dose levels were repeated with pegfilgrastim on day 2 of each cycle. The maximum tolerated dose in combination with pegfilgrastim was not exceeded. The recommended phase II dose is mitoxantrone 12 mg/m2 and ixabepilone 35 mg/m2 every 21 days, pegfilgrastim 6 mg subcutaneously day 2, and continuous prednisone 5 mg twice per day. Thirty-one percent of patients have experienced ≥ 50% prostate-specific antigen (PSA) declines, and two experienced objective responses. Of 21 patients treated with mitoxantrone 12 mg/m2 plus ixabepilone ≥ 30 mg/m2, nine (43%) experienced ≥ 50% PSA declines (95% CI, 22% to 66%).

Conclusion

These results suggest that the combination of ixabepilone and mitoxantrone is feasible and active in CRPC and requires dosing with pegfilgrastim.

Docetaxel remains a cornerstone of therapy for the patient with metastatic castration-resistant prostate cancer (CRPC). However, the landscape of CRPC therapy is changing rapidly – recently, data from the phase III TROPIC study revealed a survival advantage with the novel taxane cabazitaxel/prednisone (compared with mitoxantrone/prednisone) in a cohort of 755 men with docetaxel-refractory metastatic CRPC. Interestingly, cabazitaxel bears substantial structural similiarity to docetaxel but appears to be mechanistically distinct. In preclinical studies, the agent has antitumor activity in a variety of docetaxel-refractory in vitro and in vivo models. Subsequent to phase I testing in advanced solid tumors (where neutropenia was identified as a dose-limiting toxicity), the agent was assessed in a phase II trial in advanced, taxane-refractory breast cancer and in the aforementioned phase III TROPIC study. This review describes in detail the preclinical and clinical development of cabazitaxel.

Prostate cancer is a common cancer in men; for metastatic disease, it has a 5-year survival rate of 30%. No FDA-approved therapy for castrate-resistant prostate cancer (CRPC) known to improve survival was available until 2004, when based on a significant survival benefit over mitoxantrone, docetaxel in combination with prednisone was approved. In combination with prednisone, cabazitaxel, which was approved in the United States in 2010, is indicated for patients with metastatic CRPC previously treated with a docetaxel-containing regimen. This case report describes the treatment of a man 58 years of age who was diagnosed with advanced prostate cancer in 2006. He was initially managed with radical prostatectomy followed by androgen deprivation therapy, but a rising prostate-specific antigen (PSA) level led to enrollment in a clinical trial of HE3235 for 6 months. Subsequently, with progression of disease, he was treated with docetaxel for 4 months and then palliative radiation therapy. Cabazitaxel was initiated in October 2010; his condition stabilized within weeks, and he experienced a progressive decline in his PSA level from a peak of 5,424 ng/ml. Continued treatment with cabazitaxel resulted in his being weaned off pain medications and resuming his normal activities. After 16 cycles of cabazitaxel, his PSA declined to 994 ng/ml as of January 2012. He tolerated the cabazitaxel well and occasionally received myeloid growth factors for treatment of neutropenia; otherwise, he experienced only mild diarrhea. This response to cabazitaxel is notable, particularly in light of prior failure of multiple therapies.

Purpose:

To investigate the toxicity and efficacy of GM-CSF in castration-resistant prostate cancer (CRPC) patients who maximized their response to systemic chemotherapy.

Materials and Methods:

CRPC patients who maximized their response to either docetaxel or mitoxantrone chemotherapy were eligible if they demonstrated adequate performance status, liver, kidney, and bone marrow function. Maximum response to chemotherapy was defined as either receiving at least 8 cycles of chemotherapy without radiographic or biochemical progression, receiving less than 8 cycles as long as the prostate-specific antigen (PSA) changes by less than 10%, or being off chemotherapy for less than 12 weeks without disease progression. Patients received GM-CSF at 250 mcg/m2 subcutaneously for 14 days followed by 14 days of rest. GM-CSF was continued until disease progression.

Results:

Fifteen patients were enrolled of which all were evaluable for toxicity and 13 were evaluable for efficacy. Median age was 78 (range 66-96) and 93% of patients had a Gleason score ≥ 7. Biochemically, 2 patients (15.3%) attained partial response (PR) and 4 (30.7%) had stable disease (SD). Median time to PSA progression was 6 months (range 4-12). Radiographically, 9 patients (69.2%) had SD that lasted a median of 6 months (range 2-10). With a median follow-up of 24 months from starting GM-CSF (range 2-38), 2 patients (13.3%) remain alive and well. Median OS from start of any chemotherapy was 21 months (range 10-44). GM-CSF was well-tolerated with minimal expected manageable toxicities.

Conclusions:

GM-CSF is active post-chemotherapy in CRPC patients. Further studies with GM-CSF in this setting are warranted.