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

Bcl-2 pathway inhibition in solid tumors: a review of clinical trials

Due to their key role in the pathogenesis of cancer through the regulation of apoptosis, the B-cell leukemia/lymphoma-2 (BCL-2) family proteins have been an attractive target for cancer therapy for the past decades. Throughout the years, many Bcl-2 family inhibitors have been developed, with Venetoclax being now successfully used in treating hematological malignancies. Although their effectiveness in the treatment of solid tumors is yet to be established, some preclinical evidence indicates their possible clinical application. This review aims to summarize current data from completed clinical trials that used Bcl-2 protein family inhibitors as monotherapy or in combination with other agents for the treatment of solid malignancies. We managed to include clinical trials of various phases which analyze the pharmacokinetics and pharmacodynamics of the drugs, as well as the effectiveness and adverse effects. Active and recruiting clinical trials are also briefly presented and future prospects and challenges are discussed.

Castration-resistant prostate cancer: new science and therapeutic prospects

There is a growing number of new therapies targeting different pathways that will revolutionize patient management strategies in castration-resistant prostate cancer (CRPC) patients. Today there are more clinical trial options for CRPC treatment than ever before, and there are many promising agents in late-stage clinical testing. The hypothesis that CRPC frequently remains driven by a ligand-activated androgen receptor (AR) and that CRPC tissues exhibit substantial residual androgen levels despite gonadotropin-releasing hormone therapy, has led to the evaluation of new oral compounds such as abiraterone and MDV 3100. Their results, coupled with promising recent findings in immunotherapy (eg sipuleucel-T) and with agents targeting angiogenesis (while awaiting the final results of the CALGB trial 90401) will most probably impact the management of patients with CRPC in the near future. Other new promising agents need further development. With our increased understanding of the biology of this disease, further trial design should incorporate improved patient selection so that patient populations are those who may be most likely to benefit from treatment.

Mortality following bone metastasis and skeletal-related events among men with prostate cancer: a population-based analysis of US Medicare beneficiaries, 1999-2006

Information on the impact of bone metastasis and skeletal-related events (SREs) on mortality among prostate cancer patients is limited. Using the linked Surveillance, Epidemiology and End Results (SEER)-Medicare database, we identified men aged 65 years or older diagnosed with prostate cancer between July 1 1999 and December 31 2005 and followed to determine deaths through December 31 2006. We classified subjects as having bone metastasis and SREs as indicated by Medicare claims. Using Cox regression, we estimated mortality hazards ratios (HR) among men with bone metastasis with or without SRE, compared with men without bone metastasis. Among 126,978 men with prostate cancer (median follow-up, 3.3 years), 9746 (7.7%) had bone metastasis at prostate cancer diagnosis (1.7%) or during follow-up (5.9%). SREs occurred in 4296 (44%) men with bone metastasis. HRs for risk of death were 6.6 (95% CI=6.4-6.9) and 10.2 (95% CI=9.8-10.7), respectively, for men with bone metastasis but no SRE and for men with bone metastasis plus SRE, compared with men without bone metastasis. Bone metastasis was associated with mortality among prostate cancer patients. This association appeared to be stronger for bone metastasis plus SRE than for bone metastasis without SRE.

Chemosensitization of prostate cancer by modulating Bcl-2 family proteins

A major challenge in oncology is the development of chemoresistance. This often occurs as cancer progresses and malignant cells acquire mechanisms to resist insults that would normally induce apoptosis. The onset of androgen independence in advanced prostate cancer is a prime example of this phenomenon. Overexpression of the pro-survival/anti-apoptotic proteins Bcl-2, Bcl-xL, and Mcl-1 are hallmarks of this transition. Here we outline the evolution of therapeutics designed to either limit the source or disrupt the interactions of these pro-survival proteins. By either lessening the stoichiometric abundance of Bcl-2/xL/Mcl-1 in reference to their pro-apoptotic foils or freeing these pro-apoptotic proteins from their grip, these treatments aim to sensitize cells to chemotherapy by priming cells for death. DNA anti-sense and RNA interference have been effectively employed to decrease Bcl-2 family mRNA and protein levels in cell culture models of advanced prostate cancer. However, clinical studies are lagging due to in vivo delivery challenges. The burgeoning field of nanoparticle delivery holds great promise in helping to overcome the challenge of administering highly labile nucleic acid based therapeutics. On another front, small molecule inhibitors that block the hetero-dimerization of pro-survival with pro-apoptotic proteins have significant clinical advantages and have advanced farther in clinical trials with promising early results. Most recently, a peptide has been discovered that can convert Bcl-2 from a pro-survival to a pro-apoptotic protein. The future may lie in targeting multiple steps of the apoptotic pathway, including Bcl-2/xL/Mcl-1, to debilitate the survival capacity of cancer cells and make chemotherapy induced death their only option.

Docetaxel plus oblimersen sodium (Bcl-2 antisense oligonucleotide): an EORTC multicenter, randomized phase II study in patients with castration-resistant prostate cancer

BACKGROUND

This randomized, phase II study assessed the activity of oblimersen sodium, a Bcl-2 antisense oligonucleotide, administered before docetaxel (Taxotere) to patients with castration-resistant prostate cancer.

PATIENTS AND METHODS

Chemotherapy-naive patients with prostate-specific antigen (PSA) progression and testosterone < or = 0.5 ng/ml received docetaxel 75 mg/m2 on day 1 or oblimersen 7 mg/kg/day continuous i.v. infusion on days 1-7 with docetaxel 75 mg/m2 on day 5 every 3 weeks for < or = 12 cycles. Primary end points were confirmed PSA response (Bubley criteria) and major toxic events.

RESULTS

Confirmed PSA response was observed in 46% and 37% of 57 and 54 patients treated with docetaxel and docetaxel-oblimersen, respectively. Partial response (RECIST) was achieved in 18% and 24%, respectively. Oblimersen added to docetaxel was associated with an increase in the incidence of grade > or = 3 fatigue, mucositis, and thrombocytopenia. Major toxic events were reported in 22.8% and 40.7% of patients with docetaxel and docetaxel-oblimersen, respectively.

CONCLUSIONS

The primary end points of the study were not met: a rate of confirmed PSA response >30% and a major toxic event rate <45% were not observed with docetaxel-oblimersen.

Phase II trial of weekly patupilone in patients with castration-resistant prostate cancer

BACKGROUND

Drug resistance mechanisms can reduce response rate and duration in men with castration-resistant prostate cancer (CRPC) receiving docetaxel-based therapy. Patupilone (epothilone B), a microtubule-targeting agent, may be unaffected by some resistance mechanisms. Therefore, a phase II study assessed the patupilone safety and activity in CRPC patients with and without previous chemotherapy.

METHODS

CRPC patients received patupilone 2.5 mg/m(2) weekly for 3 weeks of a 4-week cycle. Patients were required to have measurable disease or prostate-specific antigen (PSA) progression (levels>20 ng/ml).

RESULTS

All 45 enrolled patients (median age, 69 years) were safety and response assessable. Sixty-four percent had previous chemotherapy (55% had previous taxane therapy). Patients received a median of three patupilone cycles. Patupilone was generally well tolerated. Ten (22%) patients experienced grade 3 diarrhea, six (13%) grade 3 fatigue, and one (2%) grade 3 neuropathy with no neutropenia or thrombocytopenia incidence. Six (13%) patients had >or= 50% decline in PSA (three had previous taxane therapy). No patient with measurable disease had a response. Median overall survival was 13.4 months.

CONCLUSIONS

The safety profile of weekly patupilone in CRPC patients compares favorably with that of other microtubule inhibitors. At the dose and schedule tested, patupilone demonstrated minimal activity in CRPC.

Time and bodily changes in advanced prostate cancer: talk about time as death approaches

The disease trajectory of living with incurable cancer is characterized by increasing bodily deterioration and problems. In this paper, we have focused on the change in temporal awareness as manifested in the narrations of two men with hormone refractory prostate cancer and skeletal metastases as they approach death. The two men participated in in-depth research interviews during the last part of their lives, sharing a similar disease trajectory with increasing bodily change and decreasing physical function. Both died a lingering, cancer-related death. The first and last research interviews were analyzed using a discourse analytic method. Findings show that the temporal awareness in the interviews changes as the illness progresses and death approaches. In the last interviews, the present is flooded with bodily problems; the past and the future are hardly present except for the future beyond the men's own deaths. Pain, fatigue, nausea, and other symptoms figure largely in this change, and there is no time for much more than attending to bodily needs in a present that is dominated by problems. Here, the importance of alleviating bodily problems once again becomes paramount, and two questions are raised: Is the often reported withdrawal from life, when death is imminent, a physical necessity rather than a psychological one, and is it possible to free time from the time-consuming problems of the present by means of a more concentrated attempt to alleviate these problems?

Prevalence and risk factors of bisphosphonate-associated osteonecrosis of the jaw in prostate cancer patients with advanced disease treated with zoledronate

BACKGROUND

In addition to other treatments, patients with prostate cancer (pCA) and bone metastasis receive bisphosphonates. Since 2003, a previously unknown side-effect of bisphosphonates-bisphosphonate-associated osteonecrosis of the jaws (BP-ONJ)-has been described, and frequency has since increased. An exact incidence is still unknown.

OBJECTIVES

The aim of this study was to assess the incidence and additional factors in the development of BP-ONJ.

DESIGN, SETTING, AND PARTICIPANTS

From July 2006 to October 2007, patients with advanced pCA and osseous metastasis receiving bisphosphonate therapy in the Department of Urology or Haematology and Oncology at the Johannes-Gutenberg-University Mainz, Germany, received a dental examination. In all, 43 patients were included.

MEASUREMENTS

Patients were checked for exposed bone, osteonecrosis, mucosal defects, inflammation, and oral hygiene. Further points were the applied bisphosphonate, co-medication, the duration of application, and possible trigger factors for BP-ONJ.

RESULTS AND LIMITATIONS

Eight of 43 patients developed BP-ONJ (18.6%). All patients had received zoledronate at least 14 times. Two patients had received bondronate, and one patient had received pamidronate before switching to zoledronate. All patients had had a previous tooth extraction or a denture pressure sore, and all patients had received additional chemotherapy and corticosteroids.

CONCLUSIONS

The reason for this relatively high incidence compared to other studies might be the prospective study design and thorough dental examination. In studies with such small numbers as have been published to date, nondetection or nonreported cases of BP-ONJ have an influence on the outcome. The incidence of BP-ONJ in patients with pCA might be an underestimated problem.

Pre-clinical evaluation of 1-nitroacridine derived chemotherapeutic agent that has preferential cytotoxic activity towards prostate cancer

Chemotherapy in prostate cancer (CaP) even as an adjunct has not been a success. In this communication, we report the pre-clinical efficacy of a nitroacridine derivative, C-1748 (9[2'-hydroxyethylamino]-4-methyl-1-nitroacridine) in CaP cell culture and human xenograft animal models. C-1748, a DNA intercalating agent has been derived from its precursor C-857 that was a potent anti-cancer drug, but failed clinical development due to "high" systemic toxicities. Chemical modifications such as the introduction of a "methyl" group imparted novel properties, the most interesting of which is the difference in the IC(50) values between LnCaP (22.5 nM), a CaP cell line and HL-60, a leukemia cell line (>100 nM). Using gammaH2AX as an intervention marker of DNA double strand breaks, we concluded that C-1748 is more efficacious in CaP cells than in HL-60 cells. In hormone dependent cells, the androgen receptor (AR) was identified as an additional target of C-1748. In xenograft studies, administration of C-1748 intra-peritoneally inhibited tumor growth by 80-90% with minimal toxicity. These studies identify C-1748 as a novel acridine drug that has a high therapeutic index and low cytotoxicity on myelocytic cells with potential for clinical development.

Androgen-independent prostate cancer

Androgen-independent or hormone-refractory prostate cancer (AIPC) is prostate cancer that progresses after primary androgen-ablation therapy--either orchiectomy or a gonadotropin-releasing hormone (LHRH) agonist, followed by addition and subsequent withdrawal of an antiandrogen. In the majority of patients, AIPC appears after a median time of 18 months of hormone deprivation. Patients with AIPC have a median survival between 10 and 20 months and the prognosis can be defined by using nomograms. Standard treatment is continued castration by LHRH agonists in combination with docetaxel-containing chemotherapy. Other treatment options to palliate symptoms are hormones, other chemotherapeutic agents, radioisotopes or radiotherapy and bisphosphonates. New targeted drugs and vaccination strategies are evaluated in the treatment of AIPC.

Bisphosphonates for advanced prostate cancer

BACKGROUND

Prostate cancer is the most common cancer in men in many western countries. It is characterized by its propensity for bone metastases which occur in more than 80% of patients with advanced disease. Patients are at risk of complications including pain, hypercalcaemia, bone fracture and spinal cord compression. Hormonal treatment is the mainstay of treatment for these patients but most of them will then become hormone refractory. Bisphosphonates act by inhibiting osteoclast activities and are a potential therapeutic option for metastatic prostate cancer. In addition, they have been shown to reduce pain in patients with bone metastases as a consequence of multiple myeloma. Early uncontrolled studies of bisphosphonates in metastatic prostate cancer patients have shown encouraging results.

OBJECTIVES

The objective of this review was to determine the effectiveness of bisphosphonates in relieving pain in patients with bone metastases from prostate cancer.

SEARCH STRATEGY

Studies were identified by electronic search of bibliographic databases including MEDLINE, EMBASE, CancerLit and the Cochrane Controlled Trials Register. Handsearching included Proceedings of American Society of Clinical Oncology and reference lists of all eligible trials identified.

SELECTION CRITERIA

Randomised controlled studies comparing the effectiveness of bisphosphonates with placebo or open control for pain relief in patients with bone metastases from prostate cancer.

DATA COLLECTION AND ANALYSIS

Data were extracted from eligible studies and included study design, participants, interventions and outcomes. Comparable data were pooled together for meta-analysis with intention-to-treat principle. Outcomes included pain response, analgesic consumption, skeletal events (including pathological fractures, spinal cord compression, bone radiotherapy, bone surgery), prostate cancer death, disease progression, radiological response, PSA response, adverse events, performance status, quality of life and comparisons between different routes, doses and types of bisphosphonates.

MAIN RESULTS

One thousand nine hundred and fifty-five patients from ten studies were included in this review. The pain response rates were 27.9% and 21.1% for the treatment group and the control group, respectively, with an absolute risk difference of 6.8%. The OR for pain response was 1.54 (95% CI 0.97 to 2.44, P = 0.07), showing a trend of improved pain relief in the bisphosphonate group, although this was not statistically significant. The rates for skeletal events were 37.8% and 43.0% for the treatment group and the control group, respectively, with an absolute risk difference of 5.2%. The OR for skeletal events was 0.79 (95% CI 0.62 to 1.00, P = 0.05). A significant increase in nausea was observed in patients who received bisphosphonates compared to placebo. No increase in other adverse events was observed. There was no statistically significant difference between the bisphosphonate group and the control group in terms of prostate cancer death, disease progression, radiological response and PSA response. There are insufficient data to guide the choice of bisphosphonates or the dose and the route of administration .

AUTHORS' CONCLUSIONS

Bisphosphonates should be considered for patients with metastatic prostate cancer for the treatment of refractory bone pain and prevention of skeletal events. More research is needed to guide the choice of bisphosphonates, optimal treatment schedule as well as cost-benefit comparisons. Combining results from different studies is difficult because different tools were used to assess pain, and also, bisphosphonates vary considerably in potency. This review highlights the need for standardisation and co-ordination among researchers in cancer pain studies.

Chemotherapy for advanced prostate cancer: docetaxel and beyond

To place appropriately into context the current status of chemotherapy as a management option for patients with hormone-refractory metastatic prostate cancer, it is important to reflect on the widely held historical belief that advanced prostate cancer is a chemotherapeutic-insensitive neoplasm. This article focuses on three disease subsets: (1)metastatic, hormone-refractory, chemotherapy-naive prostate cancer;(2) metastatic, hormone-refractory, progressive prostate cancer after frontline chemotherapy; and (3) locally advanced prostate cancer. Yagoda and Petrylak evaluated the results of 26 phase II trials of antineoplastics in advanced prostate cancer published between 1987 and 1991 and found the average objective response rate was less than 10% with only a few studies having response rates in the 10% to 20%range.

Pre-clinical toxicology and pathology of 9-(2′-hydroxyethylamino)-4-methyl-1-nitroacridine (C-1748), a novel anti-cancer agent in male Beagle dogs

We have developed a group of 4-substituted-1-nitroacridines with potent anti-tumor activity against prostate cancer and less toxic than parent 1-nitroacridines. The most active 9-(2'-hydroxyethylamino)-4-methyl-1-nitroacridine (C-1748) was selected for pre-clinical studies. The current study was undertaken to evaluate clinical and/or morphological adverse effects of C-1748 as a single intravenous dose at concentrations ranging from 0.16 to 4.6 mg/kg administered to male Beagle dogs. The maximum tolerated dose was 1.5 mg/kg. Emesis was observed in all groups lasting an average of 30 min to 12 h post-dosing. At high dose, extreme aggression was observed in one dog followed by disorientation and depression lasting for 48 h a frequent observation with chemotherapy. Reductions in platelets and white blood cells were observed which was similar to that seen with other chemotherapeutic agents. A compensatory hyperplasia of lymph nodes and a transient and limited extravasation in the intestinal mucosa were also observed. Increases in aspartate aminotransferase, alkaline phosphatase and creatine phosphokinase were transient with normal levels restored by day 9. These enzyme increases were accompanied by epithelial hypertrophy of larger bile ductules in the periportal triads of the liver. The low toxicity profile and high tumor target activity make this novel class of drug a promising chemotherapeutic agent.

Contribution of the 37-kDa laminin receptor precursor in the anti-metastatic PSP94-derived peptide PCK3145 cell surface binding

PURPOSE

PCK3145 is an anti-metastatic synthetic peptide with promising therapeutic efficacy against hormone-refractory prostate cancer. The characterization of the PCK3145 peptide cell surface binding/internalization mechanisms and of the receptors involved remained to be explored.

RESULTS

[(14)C]PCK3145 cell surface binding assays showed rapid and transient kinetic profile, that was inhibited by RGD peptides, laminin, hyaluronan, and type-I collagen. RGD peptides were however unable to inhibit PCK3145 intracellular uptake. Far-Western ligand binding studies enabled the identification of the 37-kDa laminin receptor precursor (37LRP) as a potential ligand for PCK3145. Overexpression of the recombinant 37LRP indeed led to an increase in PCK3145 binding but unexpectedly not to its uptake.

CONCLUSIONS

Our data support the implication of laminin receptors in cell surface binding and in transducing PCK3145 anti-metastatic effects, and provide a rational for targeting cancers that express high levels of such laminin receptors.

Reclaiming Wellness-Living With Bodily Problems, As Narrated by Men With Advanced Prostate Cancer

Having advanced prostate cancer means living with considerable bodily problems, a living we know little about. Thus, the aim of this study was to illuminate meanings of living with bodily problems, as narrated by men with advanced metastasized hormone refractory prostate cancer. Eighteen participants were interviewed, and the text was analyzed using a phenomenological-hermeneutic approach. Findings show that meanings of living with bodily problems are to live in cyclical movements between experiencing wellness and experiencing illness. New, or changed, bodily problems mean losing wellness and experiences of being ill. Understanding and, to some extent, being in control of bodily problems, make it possible to reclaim wellness and to experience oneself as being well. Findings also show that pain and fatigue are the most prominent problems and that they have different meanings. Pain being a threat of dying in agony, whereas fatigue is more of an emissary of death. Reclaiming wellness versus adaptation and enduring versus suffering deriving from 2 different perspectives, the inside or life world perspective and the outside or professional perspective, are questions discussed in the article. One clinical implication for nursing is the risk of obstructing the patients' possibility of reclaiming wellness by focusing on symptoms and disease.

Cambio en el patrón de presentación del cáncer de próstata en Oviedo en los últimos 10 años: diagnóstico y tratamiento (Parte II)

OBJECTIVES

To describe and compare the diagnostic and treatment factors of prostate adenocarcinomas diagnosed in our department in the years 1995 and 2004.

MATERIAL AND METHOD

We review the 216 patients diagnosed in both years, recording several features.

RESULTS

Significant differences were found in the mean of cylinders taken in the biopsies, being higher in 2004 than in 1995. Hormonal deprivation was the predominant treatment in 1995 followed by radical prostatectomy, while in 2004 radiotherapy (external beam or braquitherapy) was the most frequent therapy used followed by hormonal deprivation and radical prostatectomy. Independent factors to apply the treatment was the age (OR=5,6) and the risk groups (OR=2,8) in the year 2004 and only the age (>70 years vs < or =70) in the year 1995.

CONCLUSIONS

The evolution held in treatment therapies for prostate adenocarcinomas, made this disease in terms of treatment a multidisciplinary disease obtaining better results.

Results from a pilot Phase I trial of gefitinib combined with docetaxel and estramustine in patients with hormone-refractory prostate cancer

BACKGROUND

Gefitinib, which is an orally active epidermal growth factor receptor tyrosine kinase inhibitor, has demonstrated activity against hormone-refractory prostate cancer (HRPC) in preclinical studies. In this pilot Phase I trial, the authors evaluated the tolerability, efficacy, and pharmacokinetics of gefitinib combined with estramustine and docetaxel in patients with HRPC.

METHODS

Patients received gefitinib (at a dose of 250 mg/day or 500 mg/day) on each day of a 21-day treatment cycle. Docetaxel (at a dose of 60 mg/m(2)) was administered on Day 1, and estramustine (at a dose of 280 mg) was administered 3 times daily on Days 1 through 5.

RESULTS

Fifteen patients were recruited at each gefitinib dose level. The most common adverse events observed were consistent with the known profiles of gefitinib, docetaxel, and estramustine. No dose-limiting toxicity was observed. Adverse events considered to be gefitinib related included diarrhea (n = 23 patients), rash (n = 8 patients), nausea (n = 7 patients), dry skin (n = 6 patients), and emesis (n = 6 patients). Overall, 9 of 22 evaluable patients (40.9%) experienced a pain response. and 9 of 30 patients (30%) had a prostate-specific antigen response. A partial objective tumor response was demonstrated in 1 of 13 evaluable patients (7.7%) in each dose group; the median time to progression for both doses combined was 185 days (range, 28-233 days). Data comparisons within individual patients suggested that docetaxel and estramustine had no effect on gefitinib steady-state levels. Gefitinib had no effect on docetaxel exposure at the 250-mg dose but decreased exposure at the 500-mg dose. However, gefitinib may increase exposure to estramustine, particularly at the 500 mg/day dose.

CONCLUSIONS

The results of the current study demonstrated that gefitinib combined with estramustine and docetaxel had acceptable and predictable tolerability. However, it is unclear whether gefitinib provides an additional clinical benefit over docetaxel and estramustine alone.

Endocrine disrupting compounds and prostate cancer

Prostate cancer is a major health concern and is treated based on its hormone dependence. Agents that alter hormone action can have substantial biological effects on prostate cancer development and progression. As such, there is significant interest in uncovering the potential effects of endocrine disrupting compound (EDC) exposure on prostate cancer. The present review is focused on agents that alter hormone action in the prostate and how they may impact cancer growth or treatment.

Predictive factors for skeletal complications in hormone-refractory prostate cancer patients with metastatic bone disease

Factors predictive of skeletal-related events (SREs) in bone metastatic prostate cancer patients with hormone-refractory disease were investigated. We evaluated the frequency of SREs in 200 hormone-refractory patients consecutively observed at our Institution and followed until death or the last follow-up. Baseline parameters were evaluated in univariate and multivariate analysis as potential predictive factors of SREs. Skeletal-related events were observed in 86 patients (43.0%), 10 of which (5.0%) occurred before the onset of hormone-refractory disease. In univariate analysis, patient performance status (P=0.002), disease extent (DE) in bone (P=0.0001), bone pain (P=0.0001), serum alkaline phosphatase (P=0.0001) and urinary N-telopeptide of type one collagen (P=0.0001) directly correlated with a greater risk to develop SREs, whereas Gleason score at diagnosis, serum PSA, Hb, serum albumin, serum calcium, types of bone lesions and duration of androgen deprivation therapy did not. Both DE in bone (hazard ratio (HR): 1.16, 95% confidence interval (CI): 1.07-1.25, P=0.000) and pain score (HR: 1.13, 95% CI: 1.06-1.20, P=0.000) were independent variables predicting for the onset of SREs in multivariate analysis. In patients with heavy tumour load in bone and great bone pain, the percentage of SREs was almost twice as high as (26 vs 52%, P<0.02) and occurred significantly earlier (P=0.000) than SREs in patients with limited DE in bone and low pain. Bone pain and DE in bone independently predict the occurrence of SREs in bone metastatic prostate cancer patients with hormone-refractory disease. These findings could help physicians in tailoring the skeletal follow-up most appropriate to individual patients and may prove useful for stratifying patients enrolled in bisphosphonate clinical trials.

Safety and Tolerability of PCK3145, a Synthetic Peptide Derived from Prostate Secretory Protein 94 (PSP94) in Metastatic Hormone-Refractory Prostate Cancer

BACKGROUND

The safety, tolerability, and pharmacokinetic and preliminary efficacy of PCK3145 were determined in patients with metastatic hormone-refractory prostate cancer.

PATIENTS AND METHODS

PCK3145 was administered in ascending doses of 5, 20, 40, and 80 mg/m2 3 times per week for 4 weeks to cohorts of 4 patients. Dose escalation was based on dose-limiting toxicity (DLT). Pharmacokinetic profiles, tumor burden, and tumor markers (including prostate-specific antigen [PSA] and matrix metalloproteinase-9 [MMP-9] levels) were assessed. Sixteen patients received PCK3145. The median age was 66 years, and the median PSA level was 232.5 microg/L. A total of 32 cycles of therapy were administered.

RESULTS

The most common adverse events reported were pain and nausea. The only DLT was a grade 4 cardiac arrhythmia in a patient treated at the 80-mg/m2 dose level. Pharmacokinetic analysis using a 2-compartment model indicated that the mean area under the curve values increased as the dose range increased, and the mean elimination half-life ranged from 0.35 hours to 1.45 hours. The best tumor response was stable disease in 10 patients and progressive disease in 5 patients. No PSA responses were observed, but 1 patient showed a marked reduction in PSA of 41% at cycle 2. A substantial reduction in MMP-9 levels was observed in patients with baseline levels of MMP-9 > 100 microg/L.

CONCLUSION

PCK3145 was safe and well tolerated at all doses. Efficacy observations were encouraging, and the biologic activity of PCK3145 in reducing MMP-9 level may suggest a potential role of this peptide in the regulation of metastatic tumor growth.

Reduced risk of prostate cancer in men who are childless as compared to those who have fathered a child: a population based case-control study

Androgens are believed to play a major role in the etiology of prostate cancer, but studies of sex-hormone exposure in relation to risk for prostate cancer have been inconclusive. Male fertility may be an indicator of long-term androgen status. To study the role of testicular function in prostate cancer development, we have assessed number of biological children in relation to risk for this malignancy. We carried out a population-based case-control study with retrospective ascertainment of cases occurring in Sweden between 1958-98. In total, 48,850 cases of prostate cancer were identified through the nation-wide Cancer Registry. For each case, one control, matched by year of birth, was randomly selected from the Swedish population. Information on offspring was obtained from the Swedish Multi-Generation Registry. We estimated odds ratios (OR) and 95% confidence intervals (CI) for the association between number of offspring and risk for subsequent prostate cancer. Being childless or having fathered one child only were associated with reduced risks for prostate cancer compared to having fathered 2 or more children (OR = 0.83; 95% CI = 0.81-0.86 and OR = 0.93; 95% CI = 0.90-0.96, respectively). There was no further change in risk associated with fathering of more than 2 children. The risk for prostate cancer is reduced among childless men. A dysfunctioning reproductive apparatus fueling to a lesser extent prostatic growth, could be a plausible mechanism of this association.

U94 alters FN1 and ANGPTL4 gene expression and inhibits tumorigenesis of prostate cancer cell line PC3

Background

Insensitivity of advanced-stage prostate cancer to androgen ablation therapy is a serious problem in clinical practice because it is associated with aggressive progression and poor prognosis. Targeted therapeutic drug discovery efforts are thwarted by lack of adequate knowledge of gene(s) associated with prostate tumorigenesis. Therefore there is the need for studies to provide leads to targeted intervention measures. Here we propose that stable expression of U94, a tumor suppressor gene encoded by human herpesvirus 6A (HHV-6A), could alter gene expression and thereby inhibit the tumorigenicity of PC3 cell line. Microarray gene expression profiling on U94 recombinant PC3 cell line could reveal genes that would elucidate prostate cancer biology, and hopefully identify potential therapeutic targets.

Results

We have shown that stable expression of U94 gene in PC3 cell line inhibited its focus formation in culture, and tumorigenesis in nude mice. Moreover gene expression profiling revealed dramatic upregulation of FN 1 (fibronectin, 91 ± 16-fold), and profound downregulation of ANGPTL 4 (angiopoietin-like-4, 20 ± 4-fold) in U94 recombinant PC3 cell line. Quantitative real-time polymerase chain reaction (QRT-PCR) analysis showed that the pattern of expression of FN 1 and ANGPTL 4 mRNA were consistent with the microarray data. Based on previous reports, the findings in this study implicate upregulation of FN 1 and downregulation of ANGPTL 4 in the anti tumor activity of U94. Genes with cancer inhibitory activities that were also upregulated include SERPINE 2 (serine/cysteine protease inhibitor 2, 7 ± 1-fold increase) and ADAMTS 1 (a disintegrin-like and metalloprotease with thrombospondin type 1 motif, 7 ± 2-fold increase). Additionally, SPUVE 23 (serine protease 23) that is pro-tumorigenic was significantly downregulated (10 ± 1-fold).

Conclusion

The dramatic upregulation of FN 1 and downregulation of ANGPTL 4 genes in PC3 cell line stably expressing U94 implicate up-regulation of FN 1 and downregulation of ANGPTL 4 in anti tumor activity of U94. Further studies are necessary to determine functional roles of differentially expressed genes in U94 recombinant PC3 cell line, and hopefully provide leads to potential therapeutic targets in prostate cancer.

A randomized, phase II trial of ketoconazole plus alendronate versus ketoconazole alone in patients with androgen independent prostate cancer and bone metastases

PURPOSE

Alendronate (AL), a potent oral bisphosphonate, blocks the secretion of matrix metalloproteinase-2 and the establishment of bone metastases in animal models. Ketoconazole (KT) has demonstrated activity in androgen independent prostate cancer (AIPC). In this study we determined whether KT plus AL produced acceptable disease responses compared with KT alone. As the experimental design, 72 patients with progressive AIPC metastatic to bone were randomized to receive KT (1,200 mg daily) plus hydrocortisone (H) (30 mg daily) with or without AL (40 mg daily). Prostate specific antigen (PSA) consensus criteria and radiographic scans were used to determine the proportion of patients with a PSA decrease, time to progression and response duration. The pharmacokinetics of KT and AL were characterized and changes in circulating angiogenic factors were assessed.

RESULTS

At a median potential followup of 23.9 months the proportion of patients with a greater than 50% decrease in PSA was similar in the KT/H/AL and KT/H, groups (50% and 47%, respectively). The median duration of response was 8.9 and 6.3 months in the KT/H/AL and KT/H groups, respectively (p = 0.125). Median progression-free survival was not significantly prolonged in the KT/H/AL group (4.6 vs 3.8 months, p = 0.27). There was no significant difference in overall survival between the 2 treatment arms but there was a trend toward improved survival in the KT/H arm (p = 0.074). Toxicity in the 2 groups was mild and there were no clear associations between changes in circulating angiogenic factor levels and clinical outcomes in either treatment arm.

CONCLUSIONS

There were no statistically significant differences in response rate, progression-free survival or overall survival between KT/H alone and KT/H plus AL treatment in patients with AIPC. The addition of AL to KT/H may increase the response duration with an acceptable safety profile compared with treatment with KT/H alone. However, the addition of AL offers no survival benefit in patients with AIPC.

Oral estramustine plus oral etoposide in the treatment of hormone refractory prostate cancer patients: A phase II study with a 5-year follow-up

BACKGROUND

Chemotherapy regimens that target microtubular trafficking were repeatedly found to be active in the treatment of hormone refractory prostate cancer patients, but disease responses were reportedly short-lived on average.

MATERIALS AND METHODS

From 1994 to 1997, 46 consecutive patients with hormone refractory prostate cancer were enrolled in a multicenter Phase II trial of oral etoposide 100 mg/day and estramustine 560 mg/day for 21 days, followed by a 7-day rest period. Final evaluation of this trial was performed after a follow-up of 5 years.

RESULTS

Fifty-four percent of patients attained a PSA response and 46% attained a response on measurable lesions. Median time to progression (TTP) and overall survival were 7.4 and 18.4 months, respectively. Fourteen patients (30.4%) had a TTP greater than 12 months and 9 (19.5%) a TTP greater than 18 months. Sixteen patients (34.8.%) survived more than 2 years and 2 (4.3%) survived more than 5 years. One patient was still alive and free from progression more than 7 years after starting treatment.

CONCLUSIONS

This Phase II trial with a long-term follow-up revealed that some patients with hormone refractory prostate cancer could obtain durable disease response and long survival with an oral etoposide and estramustine combination regimen.

The assessment of PTEN tumor suppressor gene in combination with Gleason scoring and serum PSA to evaluate progression of prostate carcinoma

OBJECTIVE

The purpose of the study was to determine if the tumor suppressor gene phosphate and tensin homolog (PTEN) (mutated in multiple advanced cancers 1) in combination with Gleason scoring and serum prostate specific antigen (PSA) could be employed to better predict the progression of prostate carcinoma.

MATERIALS AND METHODS

The study group consisted of 43 patients with benign prostate hyperplasia (BPH), 15 with organ confined prostate carcinoma (OCPCa), and 18 with advanced prostate carcinoma (APCa). Prostate tissue samples were obtained from radical prostatectomy, transurethral resection, and TRUS guided trans-rectal needle biopsy and then evaluated for biomarker expression. The clinical stage was assessed according to tumor node metastasis classification and grade according to Gleason system. Serum PSA was measured by conventional techniques and Western blotting analysis was used to determine PTEN expression in the primary tissue. Multivariate analysis was performed to analyze whether these markers could individually predict the progression of prostate carcinoma.

RESULTS

APCa patients displayed higher Gleason scores and serum PSA levels. But much lower PTEN expression was detected in prostate of APCa patients compared to patients with BPH or OCPCa. Hormone refractory (HR) and hormone sensitive (HS) APCa cases did not yield any significant differences in terms of Gleason scoring, serum PSA and PTEN expression. PSA levels were significantly higher in patients with OCPCa or APCa compared to patients with BPH.

CONCLUSION

Our results suggested that both PTEN and serum PSA appeared to be useful as independent markers to depict the nature of tumor behavior as benign or malign. In addition, PTEN also appeared to be useful as an independent marker to predict the progression of prostate carcinoma.

Role of c-myc protein in hormone refractory prostate carcinoma: cellular response to paclitaxel

Amplification of the c-MYC proto-oncogene is a frequent alteration in hormone refractory prostate carcinomas (HRPC). In an attempt to investigate the role of c-myc in the cellular response to paclitaxel (PTX), we used two HRPC cell lines, DU145 and PC3, characterised by different levels of the protein and by different behaviour in response to taxane. In both cell lines, PTX-induced cell death was a caspase-mediated apoptosis. In DU145 cells, PTX induced an early apoptotic response associated with upregulation of c-myc restricted to the G2/M cell population. This event appeared delayed in the presence of c-myc antisense (AS-c-myc), suggesting an upstream regulation of the protein expression. In addition, the antisense approach provided evidence of an involvement of c-myc in the apoptotic response to the taxane. In contrast, in PC3 cells, the overexpressed c-myc was not modulated by drug-treatment and the addition of AS-c-myc did not affect the cell growth inhibition of PTX. In both cell lines, PTX-induced c-myc phosphorylation was concomitant with the mitotic arrest and not related to the modulation of the activation state of AKT and MAPK kinases. Our data indicate that the cellular response to PTX of HRPC cells can involve c-myc and suggest that its pro-apoptotic role is affected by the genetic background, thus supporting a complex and differentiated HRPC cell response to taxanes.

Combination with liposome-entrapped, ends-modified raf antisense oligonucleotide (LErafAON) improves the anti-tumor efficacies of cisplatin, epirubicin, mitoxantrone, docetaxel and gemcitabine

Raf-1 protein serine/threonine kinase plays an important role in cell proliferation and cell survival. We have previously described a novel cationic liposome-entrapped formulation of raf antisense oligodeoxyribonucleotide (LErafAON) and its use as a radiosensitizer. The aim of this study was to examine the effect of combination of LErafAON and a chemotherapeutic agent on growth of human prostate (PC-3) and pancreatic tumor xenografts in athymic mice (Aspc-1 and Colo 357). In PC-3 tumor-bearing mice, administration of a combination of LErafAON (i.v., 25 mg/kg/dose, x10/16) and cisplatin (i.v., 11.0 mg/kg/dose, x3), epirubicin (EPI) (i.v., 9.0 mg/kg/dose, x3) or mitoxantrone (MTO) (i.v., 2.5 mg/kg/dose, x3) led to enhanced tumor growth inhibition as compared with single agents (LErafAON+cisplatin versus cisplatin, p<0.0002, n=8; LErafAON+EPI versus EPI, p<0.0001, n=6; LErafAON+MTO versus MTO, p<0.05, n=5). In prostate or pancreatic tumor-bearing mice, combination of LErafAON (i.v., 25 mg/kg/dose, x10/13) with docetaxel (Taxotere) (i.v., 5, 7.5 or 10 mg/kg/dose, x2/4) led to tumor regression or enhanced growth inhibition as compared with single agents (PC-3: LErafAON+Taxotere versus Taxotere, p<0.02, n=7; Aspc-1: LErafAON+Taxotere versus Taxotere, p<0.03, n=5; Colo 357: LErafAON+Taxotere versus Taxotere, p<0.04, n=7). Combination of LErafAON (i.v., 25 mg/kg/dose, x10/13) with gemcitabine (i.v., 75 mg/kg/dose, x4/6) also caused a significant tumor growth inhibition in the two pancreatic carcinoma models studied (Aspc-1: LErafAON+gemcitabine versus gemcitabine, p<0.0001, n=7; Colo 357: LErafAON+gemcitabine versus gemcitabine, p<0.002, n =5). LErafAON treatment (i.v., 25 mg/kg/dose, x10) caused inhibition of Raf-1 protein expression in these tumor tissues (around 25-60%, n=4-7). Interestingly, Taxotere treatment per se also led to decreased steady state level of Raf-1 protein in PC-3 and Aspc-1 tumor tissues (i.v., 10 mg/kg/dose, x1 or 7.5 mg/kg/dose, x2; around 25-80%, n=2/6). Present studies demonstrate enhanced tumor growth inhibition or regression in response to a combination of a chemotherapeutic drug and LErafAON. These data provide a proof-of-principle for the clinical use of LErafAON in combination with chemotherapy for cancer treatment.

Capecitabine in hormone-resistant metastatic prostatic carcinoma - a phase II trial

The objective of the trial is to evaluate the efficacy of capecitabine in patients with metastatic hormone-resistant prostate carcinoma (HRPC), in terms of prostate-specific antigen (PSA) response and clinical benefit (decrease of pain or analgesic score) and its safety profile. In all, 25 patients with HRPC were enrolled on a phase II trial of capecitabine (Xeloda) at a dose of 1250 mg m(-2) orally twice daily on days 1-14 every 21 days. The inclusion criteria were PSA serum levels >3 x upper limit of normal, a WHO performance status 0-2, age <85 years and adequate bone marrow, liver and renal function. In patients with grade 2 or higher haematological toxicity on day 1 of the treatment cycle, therapy was first delayed, and then continued at a lower dose. Trial end points were PSA response and clinical benefit defined by quality of life (QL) data and analgesic consumption. The median age of patients was 70 years (range 54-85 years). A median of three cycles of capecitabine was administered (range 1-8). PSA response was observed in three patients (12%, 95% CI 3-31%), with times to tumour progression of 18, 21 and 35 weeks, respectively. In these patients, the response durations were 12, 17 and 32 weeks, respectively. Minor PSA regression was also seen in two further patients. The median time to tumour progression of all patients was 12 weeks (95% CI 9-15 weeks). Haematological toxicity was minor, with leukopenia grade 3 observed in one patient. There were three deaths during trial treatment, respectively, due to sepsis following mucositis and leukopenia, presumed sepsis with mucositis induced by chemotherapy and concomitant radiotherapy and cerebral dysfunction progressing to coma. Hand-foot syndrome grades 2 and 3 were observed in four patients each. Clinical benefit was observed in five patients (20%, CI 7-41%). Based on toxicity data, we recommend a lower starting dose of 1000 mg x m(-2) orally twice daily. While capecitabine has some activity in HRPC, as suggested by observed PSA responses, we conclude that it is not worthwhile to investigate capecitabine monotherapy in a phase III trial. Combinations of capecitabine with other agents, such as vinorelbine or docetaxel, may prove to be more effective.

Antitumor activity of irofulven monotherapy and in combination with mitoxantrone or docetaxel against human prostate cancer models

BACKGROUND

Irofulven (6-hydroxymethylacylfulvene, HMAF, MGI 114) is a novel antitumor agent currently undergoing clinical trials in hormone-refractory prostate cancer. This report examines the efficacy of irofulven alone or in combination with mitoxantrone or docetaxel against androgen-independent prostate cancer cell lines.

METHODS

To elucidate the activity of irofulven monotherapy and in combination, PC-3 and DU-145 cell lines were utilized in cellular viability assessments and tumor growth inhibition studies.

RESULTS

Viability assays with irofulven and mitoxantrone show additive to synergistic activity. Furthermore, irofulven and mitoxantrone in combination exhibit enhanced antitumor activity against PC-3 and DU-145 xenografts. Additive combination effects are also observed when irofulven and docetaxel were tested against PC-3 xenografts and curative activity (8/10 CR) is observed in DU-145 xenografts.

CONCLUSIONS

These studies demonstrate that irofulven displays strong activity as monotherapy and in combination with mitoxantrone or docetaxel against androgen-independent prostate cancer in vitro and in vivo; thus, supporting the clinical investigation of irofulven against hormone-refractory prostate cancer.

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

Value of endocrine therapy for early and locally advanced prostate cancer

Prostate-specific antigen-based screening and increased public awareness of prostate cancer have led to earlier detection of localised and potentially curable tumour stages. Nevertheless, disease recurrence after radical treatment of prostate cancer remains a problem for a considerable number of patients. Endocrine therapy plays a role in the treatment of almost all stages of prostate cancer, either as definitive or as temporary therapy. Neoadjuvant hormonal treatment has its place mainly in the external beam radiotherapy setting, where it reduces target volume and adverse effects. When used prior to and during external beam radiotherapy, endocrine therapy has shown a survival advantage in the subset of patients with locally advanced prostate cancer (cT2-4, N0-1, M0) with Gleason scores 2-6. Several studies have shown that adjuvant endocrine treatment is able to delay disease progression in any stage. There is, however, an ongoing controversy regarding the possible survival benefit of such treatment that has to be balanced against its considerable adverse effects and costs. Survival improvements associated with adjuvant hormonal treatments have mainly been seen in patients with lymph node metastases or those with a high probability of micrometastatic disease. Several large studies are under way to investigate the role of adjuvant treatment in the field of early prostate cancer.