Use of palliative end points to evaluate the effects of mitoxantrone and low-dose prednisone in patients with hormonally resistant prostate cancer

25-year perspective on prostate cancer: Conquering frontiers and understanding tumor biology

Major changes in the field of prostate cancer over the last 25 years include the implementation of prostate specific antigen screening and the recognition that BRCA confers hereditary risk of prostate cancer. Quality of life and survivorship have driven risk stratification for localized prostate cancer, facilitated by molecular signatures and leading to increased acceptance of active surveillance as a mainstream treatment option. Advances in technology have improved efficacy and reduced toxicity in both radical prostatectomy and radiation therapy for localized prostate cancer. Improved understanding of the androgen receptor has yielded substantially more effective therapies. Future growth areas include personalized treatment based on genomic and genetic information, theranostics radiopharmaceuticals, and more aggressive treatment of metastatic disease to include focal therapy. Multidisciplinary management between specialized urologists, radiation oncologists, and medical oncologists remains central to maximizing patient outcomes.

Can RECIST response predict success in phase 3 trials in men with metastatic castration-resistant prostate cancer?

BACKGROUND

Intermediate endpoints are needed in early phase studies of men with metastatic castration-resistant prostate cancer (mCRPC) that can reliably predict success in phase 3 trials. Among men with measurable disease, objective response may provide information as to whether a treatment is likely to be successful.

METHODS

We conducted a systematic review of systemic agents that have proceeded to phase 3 trials in men with mCRPC and examined the relationship between improvements in measurable disease response in phase 2 trials and successful phase 3 trials leading to regulatory approval. Only trials that included men with radiographically measurable disease were included.

RESULTS

We examined 31 eligible mCRPC phase 3 trials between 1992 and 2017 and 29 of the preceding phase 2 trials for RECIST responses. Measurable tumor responses in phase 2 trials were higher for successful therapies in phase 3 trials in chemotherapy-naive men with mCRPC, but were less correlated with success in trials investigating docetaxel combination regimens or the post chemotherapy mCRPC setting. Many failed agents did not produce higher than expected response rates over control arms; however, several agents such as anti-angiogenic therapies or orteronel produced higher than expected responses without survival benefit.

CONCLUSIONS

Objective responses in men with mCRPC may be associated with prolonged survival, but this association is mechanism dependent and inconsistent across trials or disease states. These data support considering RECIST response as a supportive but not sole endpoint in phase 2 trials to support launching phase 3 trials.

Hormone Refractory Prostate Cancer (Hrpc): Present and Future Approaches of Therapy

The mainstay of therapy for patients with advanced prostate cancer still remains androgen deprivation, although response to this is invariably temporary. Most of the patients develop hormone-refractory disease resulting in progressive clinical deterioration and, ultimately, death. Until recently there has been no standard chemotherapeutic approach for hormone refractory prostate cancer (HRPC), the major benefits of chemotherapy being only palliative. The studies combining mitoxantrone plus a corticosteroid demonstrated that chemotherapy could be given to men with symptomatic HRPC with minimal toxicity and a significant palliation could be provided. Recently, results from 2 phase III randomized clinical trials demonstrating that a combination of docetaxel plus prednisone can improve survival in men with HRPC have propelled docetaxel-based therapy into the forefront of treatment options for these patients as the new standard of care. There is a promising activity of new drug combinations such as taxanes plus vinca alkaloids; bisphosphonates are assuming a prominent role in prostate therapy through their ability to prevent skeletal morbidity. Combinations of classic chemotherapeutic agents and biological drugs began to be tested in phase II-III trials and the first results appear interesting. This article focuses on combinations recently evaluated or under clinical development for the treatment of HRPC.

Is There a Standard Chemotherapeutic Regimen for Hormone-Refractory Prostate Cancer? Present and Future Approaches in the Management of the Disease

Prostate cancer that no longer responds to hormonal manipulation can be defined as hormone-refractory prostate cancer. Until recently, there has been no standard chemotherapeutic approach for hormone-refractory prostate cancer. The major benefits of chemotherapy in the treatment of the disease are palliative in nature, in terms of reduction of pain and use of analgesics and improvement of performance status, as followed in the most recent trials. Phase III studies are necessary to better evaluate the efficacy of the different regimens, because several old studies suffer for methodological deficits. There is a promising activity of new drug combinations, such as vinca alkaloids and taxanes. Phase I and II trial are testing combinations of classic chemotherapeutic agents and biologic drugs, and the first results appear interesting. In this article, recent advances in the treatment of hormone-refractory prostate cancer using chemotherapeutic regimens are critically reviewed.

Evaluation of Palliative Endpoints in Oncology Clinical Trials

Background

In recent years, there has been a growing recognition that improvements in quality of life may be as important as improvements in quantity of life in patients with advanced cancer. With this goal in mind, many oncology trials now seek to evaluate palliative endpoints as well as disease progression and survival.

Methods

Methodologic advances and challenges in evaluating palliative endpoints in oncology clinical trials are reviewed.

Results

Valid and reliable self-report measures have been developed that permit evaluation of palliative endpoints. Issues to consider in conducting research on palliative endpoints include the selection of appropriate outcome measures, the number and timing of outcome assessments, and the handling of missing data.

Conclusions

The inclusion of palliative endpoints into clinical trials in oncology has the potential to advance clinical care by identifying chemotherapeutic agents that are effective in improving the quality of life of patients with advanced cancer.

Treatment of hormone-refractory prostate cancer

Objective. An increasing number of patients with prostate cancer develop hormone-refractory disease after standard treatment modalities. In these patients, early clinical trials with chemotherapy produced disappointing response rates. However, clinical trials that employ response criteria such as prostate-specific antigen (PSA) and clinical benefit response have produced encouraging responses. This article reviews current and future treatment options for the management of hormone-refractory prostate cancer.

Data Sources. A MEDLINE search for the years 1978 to 1998 was completed. The following terms were used in our search: prostate cancer, hormone-refractory, treatment, and chemotherapy. Relevant articles referenced in the literature obtained in our MEDLINE search were reviewed.

Study Selection. Randomized and nonrandomized clinical trials were used in our review. Clinical trials using prostate-specific antigen or a palliation of symptoms as primary criteria for response were given priority.

Data Synthesis. Several genetic alterations, including the overexpression of bcl-2 or mutations in p53, may lead to the development of hormone-refractory prostate cancer. Agents such as estramustine and taxanes, which affect microtubule function and potentially modulate bcl-2, appear to be particularly active in the treatment of hormone-refractory prostate cancer. In addition, mitoxantrone as well as other agents has been shown to be beneficial in improving the quality of life in patients with hormone-refractory prostate cancer.

Conclusion. Hormone-refractory prostate cancer is not a chemotherapy-resistant disease as once believed; significant progress in the treatment of hormone-refractory prostate cancer has been made with new combinations of chemotherapy agents. Promising new treatments are currently under evaluation to assess their potential benefit over the standard treatment modalities that are currently available.

A patient-level data meta-analysis of standard-of-care treatments from eight prostate cancer clinical trials

Open clinical trial data offer many opportunities for the scientific community to independently verify published results, evaluate new hypotheses and conduct meta-analyses. These data provide valuable opportunities for scientific advances in medical research. Herein we present the comparative meta-analysis of different standard of care treatments from newly available comparator arm data from several prostate cancer clinical trials. Comparison of survival rates following treatment with mitoxantrone or docetaxel in combination with prednisone as well as prednisone alone, validated the previously demonstrated superiority of treatment with docetaxel. Additionally, comparison of four testosterone suppression treatments in hormone-refractory prostate cancer revealed that subjects who had undergone surgical castration had significantly lower survival rates than those treated with LHRH, anti-androgen or LHRH plus anti-androgen, suggesting that this treatment option is less optimal. This study illustrates how the use of patient-level clinical trial data enables meta-analyses that can provide new insights into clinical outcomes of standard of care treatments and thus, once validated, has the potential to help optimize healthcare delivery.

Androgen-glucocorticoid interactions in the era of novel prostate cancer therapy

Great strides have been made in the treatment of castration-resistant prostate cancer (CRPC) with the development of new antiandrogens (enzalutamide) and more potent androgen synthesis inhibitors (abiraterone) that have both improved patient outcomes. These new drugs have also helped unravel the complex biology of androgen-androgen receptor driven prostate cancer and brought into prominence various mechanisms triggering the development of drug resistance and tumour cell survival despite use of androgen deprivation therapy (ADT). The complex role of glucocorticoids in the treatment, management and progression of patients with CRPC is integral to these advances. Historically, glucocorticoid treatment has resulted in both subjective and objective responses in patients with advanced-stage prostate cancer. With the use of these new therapeutic agents, however, unexpected glucocorticoid-related mechanisms that can cause iatrogenic stimulation of prostate cancer growth have emerged, which might contribute to drug resistance and disease progression despite optimal ADT. For example, the upregulation of glucocorticoid receptors (GRs) during enzalutamide therapy results in glucocorticoid-GR-mediated regulation of androgen target genes, leading to escape from enzalutamide blockade. Thus, understanding the biological role of glucocorticoids in patients with prostate cancer is of major importance in the era of new and evolving antiandrogen therapies.

Assessment of anticancer-treatment outcome in patients with metastatic castration-resistant prostate cancer-going beyond PSA and imaging, a systematic literature review

BACKGROUND

In the past years, there has been significant progress in anticancer drug development for patients with metastatic castration-resistant prostate cancer (CRPC). However, the current instruments to assess clinical treatment response have limitations and may not sufficiently reflect patient benefit. Our objective was to systematically identify tools to evaluate both patient benefit and clinical anticancer-treatment response as basis for an international consensus process and development of a specific pragmatic instrument for men with CRPC.

METHODS

PubMed, Embase and CINAHL were searched to identify currently available tools to assess anticancer-treatment benefit, other than standard imaging procedures and prostate-specific antigen measurements, namely quality of life (QoL), detailed pain assessment, physical function and objective measures of other complex cancer-related syndromes in patients with CRPC. Additionally, all CRPC phase III trials published in the last 5 years were reviewed as well as studies using physical function tools in a general cancer population. The PRIMSA statement was followed for the systematic review process.

RESULTS

The search generated 1096 hits, 185 full-text papers were screened and finally 73 publications were included. Additional 89 publications were included by hand-search. We identified a total of 98 tools used in CRPC trials and grouped these into three categories: 22 tools assessing QoL domains and subgroups, 47 tools for pain assessment and 29 tools for objective measures, mainly physical function and assessment of skeletal disease burden.

CONCLUSION

A wide variety of assessment tools and also efforts to standardize and harmonize patient-reported outcomes and pain assessment were identified. However, the specific needs of the increasing CRPC population living longer with their incurable cancer are insufficiently captured and objective physical outcome measures are under-represented. In the age of new anticancer drug targets and principles, new methods to monitor patient relevant outcomes of antineoplastic therapy are of utmost importance.

Metabolism and pharmacokinetics of radium-223 in prostate cancer

INTRODUCTION

Prostate cancer metastatic to bone is a cause of significant morbidity and mortality. Bone pain and other skeletal events negatively impact the quality of life in patients who might otherwise be functioning well. As such, there has been intense interest in the development of strategies and pharmaceuticals to address this problem.

AREAS COVERED

The authors reviewed the current literature for articles relevant to metastatic prostate cancer, clinical radiopharmaceuticals, castrate-resistant prostate cancer and development of Radium-223 . The authors have referenced primary literature, clinical trials and relevant review articles that summarize the history, development and current utilization of radiopharmaceuticals for management of bone metastases from prostate cancer.

EXPERT OPINION

Radium-223 is the first radiopharmaceutical with an overall survival benefit approved for the treatment of patients with castration-resistant prostate cancer, symptomatic bone metastasis and no known visceral metastatic disease. The additional benefit of clinically significant improved overall survival should lead to exploration of whether this agent can be used earlier in the treatment algorithm or combined with chemotherapy or androgen deprivation therapy. An individualized approach needs to be tailored to each patient based on their overall symptoms, disease burden, hematologic profile and goals of care.

The functional and psychosocial status of patients with disseminated bladder cancer

This study describes self-reported functional and psychological status of patients using The European Organization for Research and Treatment of Cancer Quality of Life Questionnaire (QLQ-C30) and relates this to the prognosis. Patients with incurable locally advanced or metastatic transitional cell cancer of the urothelial tract were prospectively included in a study of self-reported functional and psychosocial status. The study included 25 patients; 19 patients completed one or more Quality of Life Questionnaires. The median survival was 5.2 months, and there was a significant relation between functional, emotional, and social status and survival. The self-assessment of functional status was a better prognostic factor for survival than performance status evaluated by the clinician. The value of the global quality of life scale did not relate to survival after recurrence. Functional, emotional, and quality of life scales declined during the progression of the disease. The study suggests that evaluation with self-reporting questionnaires may provide the physician with useful information, and it may aid in making treatment decisions in patients with metastatic bladder cancer.

Absence of antitumor activity with prednisone in patients with progressive androgen-independent prostate carcinoma

Corticosteroids are reported to have antitumor activity in patients with androgen-independent prostate carcinoma (AIPCa). This trial, a phase II trial of daily oral prednisone 10 mg four times per day for 56 consecutive days, was designed to confirm this finding. From November 1989 to September 1992 16 patients were enrolled in the study. Baseline tumor measurements were taken upon enrollment and re-evaluated at completion of 56 days. If the patient was responding or stable, a maintenance schedule of 5 mg four times per day was resumed until unacceptable toxicity was reached or tumor growth progressed. Antitumor activity was assessed by the decline in the serum level of prostate specific antigen. Entry criteria included strict evidence for progressive AIPCa, tumor growth associated with castrate testosterone level below 50 ng/dl, and adrenal cortical function tests. Patients continued hormone therapy that induced castrate testosterone level. Two patients required early cessation of therapy secondary to symptomatic tumor progression. Of the remaining 14 patients, no responses were seen,. Four (29%) of 16 patients had transient improvement in performance status. No hematologic toxicity was observed. Nonhematologic toxicity was mild and manageable, consisting of fluid retention and metabolic laboratory abnormalities. Suppressive effect of adrenal cortical function was demonstrated in patients, measured by a decrease in serum levels of dehydroepiandrosterone and dehydroepiandrosterone sulfate. Our results show that corticosteroids have no significant antitumor activity in patients with true progressive AIPCa.

Clinical development of novel therapeutics for castration-resistant prostate cancer: historic challenges and recent successes

There have been more drugs approved by the US Food and Drug Administration for the treatment of castration-resistant prostate cancer in the past 3 years than in the prior 3 decades, with additional drugs on the verge of approval based on the results of recently reported randomized trials. While an improvement in the understanding of the pathogenesis of castration-resistant prostate cancer has undeniably accelerated the transition of novel approaches from "bench to bedside," the recent successes in the treatment of prostate cancer are also a result of the efforts of clinical investigators to redefine the framework in which drugs for castration-resistant disease are evaluated. This review will explore the shifting paradigm in drug development for castration-resistant prostate cancer over the past several decades, and highlight how new definitions, trial designs, and endpoints have facilitated the emergence of new therapies for this challenging disease.

Validity of four pain intensity rating scales

The Visual Analogue Scale (VAS), Numerical Rating Scale (NRS), Verbal Rating Scale (VRS), and the Faces Pain Scale-Revised (FPS-R) are among the most commonly used measures of pain intensity in clinical and research settings. Although evidence supports their validity as measures of pain intensity, few studies have compared them with respect to the critical validity criteria of responsivity, and no experiment has directly compared all 4 measures in the same study. The current study compared the relative validity of VAS, NRS, VRS, and FPS-R for detecting differences in painful stimulus intensity and differences between men and women in response to experimentally induced pain. One hundred twenty-seven subjects underwent four 20-second cold pressor trials with temperature order counterbalanced across 1°C, 3°C, 5°C, and 7°C and rated pain intensity using all 4 scales. Results showed statistically significant differences in pain intensity between temperatures for each scale, with lower temperatures resulting in higher pain intensity. The order of responsivity was as follows: NRS, VAS, VRS, and FPS-R. However, there were relatively small differences in the responsivity between scales. A statistically significant sex main effect was also found for the NRS, VRS, and FPS-R. The findings are consistent with previous studies supporting the validity of each scale. The most support emerged for the NRS as being both (1) most responsive and (2) able to detect sex differences in pain intensity. The results also provide support for the validity of the scales for use in Portuguese samples.

Novel therapeutics for the management of castration-resistant prostate cancer (CRPC)

Androgen-deprivation therapy is the initial treatment for metastatic prostate cancer. Although highly effective, all men who live long enough will eventually experience disease progression and develop castration resistance. Patients who have castration-resistant prostate cancer (CRPC) have a median survival of ≈1-3 years. When evaluating novel therapies for CRPC, one must consider the endpoints measured for determination of response. We will discuss PSA, circulating tumour cells, progression-free survival, overall survival, and other endpoints used in clinical trials. Docetaxel and sipuleucel-T are currently the preferred first-line treatment options for patients with CRPC; cabazitaxel is a new option for patients after docetaxel failure. Patients with CRPC historically have very poor survival, underscoring the unmet need for novel therapeutics. Although many agents appear promising, well-designed randomized phase III trials are necessary to establish their impact on survival and health-related quality of life. Promising new therapies include hormonal agents, such as abiraterone and MDV3100, as well as other novel immunotherapeutics and anti-prostate-specific membrane antigen therapies. In the future, we anticipate therapies tailored to individual patients' malignancies using various molecular analyses.

Vaccine therapy with sipuleucel-T (Provenge) for prostate cancer

As the most common malignancy among North American males, prostate cancer causes more than 30,000 deaths each year. After local and hormonal treatments, a great number of patients ultimately progressed to castrate-resistant prostate cancer (CRPC), in which chemotherapy provides a small survival advantage, but with significant toxicities. In the past decade, prostate cancer has become a target for several immunotherapeutic approaches. Sipuleucel-T (Provenge®, or APC8015) is a novel cancer vaccine developed from autologous dendritic cells (DC) loaded with engineered fusion protein of prostatic acid phosphatase (PAP) and granulocyte-macrophage colony-stimulating factor (GM-CSF). Phase I and Phase II trials show that the vaccine is safe and effective in creating immune responses toward the fusion-protein target antigen, PAP-GM-CSF also call PA2024. Recent Phase III studies also demonstrated sipuleucel-T's efficacy in prolonging median survival in patients with CRPC, despite little or no effect on clinical disease progression or surrogates such as serum PSA kinetics. Subsequently, the United States Food and Drug Administration approved sipuleucel-T for the treatment of asymptomatic or minimally symptomatic CRPC in April 2010. Filings are projected with international regulatory agencies in 2011. While the development of sipuleucel-T provides an option for patients with early CRPC, it also introduces physicians and researchers to new unanswered questions regarding its optimal clinical use and questions about mechanism of action and combination and sequencing with other agents.

Impact of docetaxel-based chemotherapy on quality of life of patients with castration-resistant prostate cancer: results from a prospective phase II randomized trial

What's known on the subject? and What does the study add? Data on quality of life during docetaxel treatment in castration resistant prostate cancer was mainly provided by SWOG and TAX327 trials. In the TAX327 trial biochemical response and pain predicted survival, whereas quality of life outcomes did not. In the present study, there were no statistically significant changes in the quality of life scales during treatment except in the case of patients receiving docetaxel and estramustine, who experienced a significant decrease in pain. Our data seem to suggest that patients with a better baseline quality of life (and consequently with fewer symptoms) are more likely to achieve a biochemical response.

OBJECTIVES

• To assess quality of life (QoL) outcomes and pain changes in patients affected by castration-resistant prostate cancer enrolled in a phase II randomized trial of 3-week docetaxel (DOC)-based chemotherapy. • To provide further data to clarify the conflicting published data concerning the impact of DOC on the patients' QoL.

PATIENTS AND METHODS

• QoL outcomes were assessed using the European Organisation for the Research and Treatment of Cancer QLQ-C30 questionnaire. • Pain changes were evaluated by means of the Brief Pain Inventory at baseline and after every two DOC courses. • The patients completing at least two questionnaires (at baseline and before the third course) were considered evaluable.

RESULTS

• In all, 59 patients were evaluable. • Asymptomatic patients and responders had a better baseline QoL than symptomatic patients and non-responders. • There were no statistically significant changes in the QLQ-C30 scales during treatment except in the case of patients receiving DOC and estramustine, who experienced a significant decrease in pain. • There was a progressive improvement in the mean intensity and interference scores of the Brief Pain Inventory.

CONCLUSIONS

• Our data confirm that QoL is generally maintained during chemotherapy. • There is a substantial reduction in pain. • Our results also suggest that baseline QoL may predict treatment response.

Sipuleucel-T: harbinger of a new age of therapeutics for prostate cancer

Sipuleucel-T (Provenge) is the first therapeutic cancer vaccine approved by the US FDA. The approval heralds the long-awaited promise of improved patient survival with minimal toxicity by therapies designed to generate an active, specific anticancer immune response. The development of this first-in-class agent as well as other therapeutic vaccines in clinical evaluation has also led to a better understanding of relevant patient populations and end points for clinical trials. This article discusses the development and approval of sipuleucel-T in the context of other approved therapies for prostate cancer, as well as controversies and novel paradigms brought about by this new agent.

Therapeutic cancer vaccine fulfills the promise of immunotherapy in prostate cancer

For many years, preclinical and clinical studies have attempted to harness the power of the immune system and focus it on malignant cells in an attempt to improve clinical outcomes for patients with cancer. This paper describes the landmark Phase III trial that led to the first US FDA approval of a therapeutic cancer vaccine. In a randomized trial of 512 patients, those treated with sipuleucel-T survived for 25.8 months compared with those treated with placebo, who survived 21.7 months (HR: 0.78; p = 0.03). There was, however, no change in time to progression, which may relate to the underlying mechanism of this new class of therapeutics.

Estimating clinically meaningful changes for the Functional Assessment of Cancer Therapy--Prostate: results from a clinical trial of patients with metastatic hormone-refractory prostate cancer

OBJECTIVE

To determine clinically meaningful changes (CMCs) for the Functional Assessment of Cancer Therapy-Prostate (FACT-P).

METHODS

We obtained data from a Phase III trial of atrasentan in metastatic hormone-refractory prostate cancer patients (n = 809). We determined anchor-based differences using Karnofsky Performance Status (KPS), bone alkaline phosphatase (BAP), hemoglobin, time to disease progression (TTP), adverse events (AE), and survival. One-third and one-half standard deviation and standard error of measurement (SEM) were used as distribution-based criteria for CMCs. Comparison across baseline FACT-P domains and derived scales [FACT-P total score, Trial Outcome Index (TOI) score, prostate cancer subscale (PCS) score, pain-related score, and FACT Advanced Prostate Symptom Index (FAPSI)] were conducted for KPS, BAP, and hemoglobin using Student's t tests. Twelve-week change scores were compared for TTP, AE, and survival using ANCOVA.

RESULTS

CMCs were estimated as 6 to 10 for FACT-P total score, 5 to 9 for FACT-P TOI score, 2 to 3 for FACT-P PCS, 1 to 2 for the 4 PCS pain-related questions, and 2 to 3 for FAPSI. CMCs were also estimated using distribution-based criteria. Kappa statistics were computed to determine the degree of correspondence between the recommended guideline of 1.0 SEM and empirically derived standards. Most of the kappas for health-related quality of life domains and SEM standards had "substantial" to "almost perfect" concordance.

CONCLUSIONS

The significant relationship between clinical and quality of life data provides support for the use of CMCs to increase interpretability of FACT-P scores.

NCIC Clinical Trials Group experience of employing patient-reported outcomes in clinical trials: an illustrative study in a palliative setting

In this article we briefly review the experience of the National Cancer Institute of Canada (NCIC) Clinical Trials Group (CTG) with respect to the assessment of patient reported outcomes in clinical trials, and illustrate issues important to assessing symptom palliation in clinical trials of cancer therapy. We highlight a standard approach taken by the NCIC CTG, and illustrate how this approach may be applied to the complex problem of symptom control analysis in patients with locally advanced NSCLC. We further illustrate how variations in this analysis yield different apparent rates of palliation. Apparent rates of palliation critically depended on the outcome measures used: single symptom response across patients (5-32%, depending on the symptom of interest), symptom response in specific symptomatic patients (37-100%), symptom control (45-82%), index symptom response (60%), proportion of patients experiencing improvement in all symptoms (21%), or health-related quality of life (HRQoL) improvement (23%, global). Rates also varied substantively depending on which cohort of patients was considered relevant to each analysis (i.e., was included in the respective denominator). Substantive discordance in patients' apparent palliation was seen when HRQoL data were compared with symptom diary data. Appropriate and valid descriptions of palliative outcomes in clinical trials are complex undertakings. We conclude that several measures are required for a textured clinical description of outcome, and recommend reporting palliation according to individual symptom response rates and HRQoL response rates, in order to address each construct of palliation success.

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.

Sensitizing hormone-refractory prostate cancer cells to drug treatment by targeting 14-3-3sigma

Advanced and hormone-refractory prostate cancer has long been considered as a chemoresistant disease. Recently, it was found that 14-3-3sigma expression increases as prostate tumor progresses, and that 14-3-3sigma contributes significantly to drug resistance in breast cancers. We, thus, hypothesized that advanced and hormone-refractory prostate cancers may have an increased level of 14-3-3sigma, which in turn may contribute to drug resistance in advanced and hormone-refractory prostate cancers. In this study, we tested this hypothesis and found that, indeed, the expression level of 14-3-3sigma in androgen-independent prostate cancer cell lines DU145, PC3, and CWR22RV are much higher than that in the androgen-dependent cell line LNCaP, and that the androgen-independent cells are more resistant to mitoxantrone and Adriamycin than the androgen-dependent cells. Depleting 14-3-3sigma expression in DU145 and CWR22RV by RNA interference significantly sensitized these cells to mitoxantrone and Adriamycin by abrogating G2-M checkpoint and increasing apoptosis, whereas restoring 14-3-3sigma expression in LNCaP cells enhanced drug resistance. We also showed that 14-3-3sigma deficiency caused nuclear localization of Cdc2 and dephosphorylation of the Tyr15 residue upon DNA damage. Based on these studies, we propose that therapeutic intervention targeting 14-3-3sigma may be useful for sensitizing hormone-refractory prostate cancers to chemotherapy by both G2-M checkpoint abrogation and apoptosis enhancement.

Quality of life as a potential predictor for morbidity and mortality in patients with metastatic hormone-refractory prostate cancer

BACKGROUND

The association between HRQL measures with outcomes in patients with metastatic hormone-refractory prostate cancer (HRPC) is unclear.

METHODS

Baseline and 12-week HRQL was collected using the European Organization for Research and Treatment of Cancer (EORTC QLQ-C30) and the Functional Assessment of Cancer Therapy - Prostate (FACT-P). Outcomes included: (1) survival; (2) time to disease progression and (3) time to bone pain. Cox proportional hazards regression models were used. The relative predictive performance of each HRQL instrument and domain was compared.

RESULTS

Baseline HRQL scores and 12-week change scores > the median were significant predictors of all clinical outcomes but varied by domain. For example, the hazard of death for a change in FACT-P Grand Total Score > median was 49% of the hazard for a change < or = the median. Including baseline or 12-week change in HRQL resulted in improvement in prediction performance.

CONCLUSIONS

Patients with better baseline HRQL have better predicted survival, time to disease progression and pain prognosis than those with worse HRQL. In addition, the 12-week change in HRQL appears to improve predictive accuracy for most clinical outcomes. It appears that greater deterioration in HRQL is prognostic for rapid disease progression.

Changing perspectives of the role of chemotherapy in advanced prostate cancer

The use of cytotoxic chemotherapy in advanced prostate adenocarcinoma has been validated by the recent demonstration of survival benefit in two large randomized phase III trials. Before publication of these landmark trials, SWOG 9916 and TAX 327, no chemotherapeutic regimen had shown survival benefit in the treatment of androgen independent prostate cancer (AIPC). These trials provide new encouragement for the use of chemotherapy in all stages of disease. Improved communication between medical and urologic oncologists and early patient referral for clinical trial participation remains essential for identifying new chemotherapeutic regimens with improved activity in AIPC and for defining the role of chemotherapy in earlier-stage disease. This article discusses the role of chemotherapy as the current standard of care for the treatment of AIPC and provides a historical perspective of the trials that preceded the development of current docetaxel-based regimens.

Management of Advanced Prostate Cancer After First-Line Chemotherapy

Hormone refractory prostate cancer (HRPC) causes substantial morbidity and mortality. There are increasing options for both first- and second-line therapy in the palliative treatment of patients with HRPC. Medications to control symptoms should first be optimized in patients with late-stage disease, and radiotherapy applied to dominant painful bone lesions. Docetaxel, mitoxantrone, satraplatin, and ixabepilone are active chemotherapeutic agents in the first- and/or second-line setting for patients with HRPC, and this may be true also of older drugs such as oral cyclophosphamide and vinorelbine. Radioisotopes such as strontium and samarium are useful for treatment of more generalized bone pain. Third-line hormonal maneuvers including glucocorticoids, ketoconazole, and estrogens can lead to further palliation in some patients, and there are provocative data that chemotherapy might restore hormonal sensitivity in a subset of patients.

Assessment of quality of life in the supportive care setting of the big lung trial in non-small-cell lung cancer

PURPOSE

The Big Lung Trial (BLT) was a large, pragmatic trial to evaluate the addition of chemotherapy to primary treatment (ie, surgery, radical radiotherapy, or supportive care) in non-small-cell lung cancer (NSCLC). In the supportive care group, there was a small but significant survival benefit in patients treated with chemotherapy compared with supportive care alone (no chemotherapy). A substudy was undertaken to evaluate the quality of life (QoL) implications of the treatment options. QoL was assessed using European Organisation for Research and Treatment of Cancer (EORTC) Quality of Life Questionnaires C30 (QLQ-C30) and LC17, and daily diary cards.

PATIENTS AND METHODS

EORTC QLQ-C30 and LC17 were collected at 0, 6 to 8, 12, 18, and 24 weeks. Diary cards were completed during the first 12 weeks of the study. The primary end point was global QoL at 12 weeks.

RESULTS

A total of 273 patients were randomly assigned: 138 to no chemotherapy and 135 to chemotherapy. There was no evidence of a large detrimental effect on QoL of chemotherapy. No statistically significant differences in global QoL or physical/emotional functioning, fatigue and dyspnea, and pain were detected at 12 weeks. Higher rates of palliative radiotherapy in the no chemotherapy arm may have lessened differences in QoL. Global QoL, role functioning, fatigue, appetite loss, and constipation were prognostic indicators of survival at 12 weeks.

CONCLUSION

There were no important adverse effects of chemotherapy on QoL.

Chemotherapy for prostate cancer: finally an advance!

Patients with metastatic prostate cancer can be treated with androgen deprivation strategies; however, most patients will eventually develop androgen-independent prostate cancer (AIPC). Until recently, chemotherapy has been shown to palliate symptoms of disease but not improve survival. Now 2 large phase 3 trials have demonstrated an overall survival advantage for docetaxel-based regimens compared with the best standard of care. This firmly cements docetaxel-based therapies as the standard of care for patients with metastatic androgen-independent disease. In addition, this foundation provides a platform for the translation of novel agents into new combination cancer therapies. In this paper, we not only review standard treatment options available for AIPC including the recently completed docetaxel trials, but also present some of the promising new drug combinations of currently available drugs.

A modified low-dose regimen of mitoxantrone and prednisolone in patients with androgen-independent prostate cancer

BACKGROUND

We conducted this retrospective study to analyze a modified dose schedule of mitoxantrone and prednisolone (MP) in patients with androgen-independent prostate cancer.

METHODS

From June 1997 to April 2002, 28 patients were enrolled. Their median age was 69 years (range, 58-79 years). The median duration of hormonal therapy was 30 months (range, 6-84 months). The median performance status was 2. Sixteen of the patients had bone disease only. The chemotherapy consisted of 8 mg/m2 mitoxantrone by intravenous infusion every 3 weeks and 10 mg prednisolone orally twice per day. WHO response criteria, prostatic-specific antigen (PSA), pain and performance status were used to assess the response.

RESULTS

The median number of treatment cycles was six (range, 2-20). Nine (32.1%) and 15 patients (53.8%) had > or =80% and > or =50% reduction in serum PSA level, respectively. Of 16 patients using narcotics, five (31.3%) had a > or =50% reduction in narcotics consumption compared with the baseline. Nine patients (32.1%) showed improved performance. For 12 patients with measurable disease, only two (16.7%) showed a partial response. Grade 3-4 toxicities included neutropenia (three patients), anemia (three patients) and vomiting (one patient). The median survival was 12 months and the median time to PSA progression was 4 months.

CONCLUSIONS

This modified regimen is feasible for palliative intent. The toxicity of this regimen is manageable. Exploring further combinations of this regimen with novel agents against androgen-independent prostate cancer is warranted.

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.

Combination of LHRH analog with somatostatin analog and dexamethasone versus chemotherapy in hormone-refractory prostate cancer: a randomized phase II study

OBJECTIVES

To evaluate prospectively the combination of a luteinizing hormone-releasing hormone analog with a somatostatin analog and dexamethasone in patients with hormone-refractory prostate cancer (HRPC) in a randomized Phase II study. HRPC presents a challenging therapeutic problem. Salvage chemotherapy is the usual approach at this stage of the disease. The combination of a luteinizing hormone-releasing hormone analog with a somatostatin analog and dexamethasone has produced objective clinical responses in HRPC.

METHODS

Forty patients with HRPC were randomized to receive one of two treatments. Group 1 underwent chemotherapy (estramustine 140 mg three times daily and etoposide 100 mg orally for 21 days) and group 2 the combination of a somatostatin analog (lanreotide 30 mg intramuscularly every 14 days) and dexamethasone (4 mg tapered to 1 mg), in addition to androgen ablation by orchiectomy or a luteinizing hormone-releasing hormone analog (triptorelin 3.75 mg intramuscularly every 28 days). The clinical and prostate-specific antigen (PSA) response, overall survival, time to progression, and toxicity were compared between the two groups.

RESULTS

The data of 20 patients in group 1 and 18 in group 2 were analyzed. The demographic and clinical data were similar in the two groups at study entry. A PSA response (decrease of greater than 50%) was observed in 45% of group 1 and 44% of group 2. The difference was not statistically significant. A partial clinical response was observed in 29% and 30% of groups 1 and 2, respectively. Again, the difference was not statistically significant. Changes in performance status and pain score during treatment were not significantly different in the two groups. Hematologic toxicity was more frequent in group 1 (80% of patients), and mild diabetes was more frequent in group 2 (22% of patients). The overall survival was 18.8 months in group 1 and 18 months in group 2 (not statistically significant). The time to progression was 6 versus 4 months and, in the PSA responder subgroup, it was 8 versus 7.7 months in groups 1 and 2, respectively (neither difference was statistically significant).

CONCLUSIONS

The results of our randomized Phase II study indicated that the new combination treatment (luteinizing hormone-releasing hormone analog, somatostatin analog, and dexamethasone) may be equally effective as salvage chemotherapy in patients with HRPC in terms of the clinical and PSA response, overall survival, and time to progression. A larger prospective Phase III trial is required to confirm our observations.

Brief assessment of priority symptoms in hormone refractory prostate cancer: the FACT Advanced Prostate Symptom Index (FAPSI)

BACKGROUND

The objective of this study was to construct and validate a brief, clinically-relevant symptom index for advanced prostate cancer.

METHODS

Questions were extracted from a commonly-used multi-dimensional cancer quality of life instrument with prostate-specific items, the Functional Assessment of Cancer Therapy-Prostate (FACT-P). Surveys of disease-related symptoms were presented to an international sample of 44 expert physicians. Each expert narrowed the list to no more than five of the most important symptoms or concerns to monitor when assessing the value of treatment for advanced prostate cancer. Symptoms/concerns endorsed at a frequency greater than chance probability (17%) were retained for the symptom index and called the FACT Advanced Prostate Symptom Index-8 (FAPSI-8): pain (three items), fatigue, weight loss, urinary difficulties (two items), and concern about the condition becoming worse. The FAPSI-8 was validated using data from a clinical trial of 288 men being treated for hormone refractory prostate cancer.

RESULTS

The FAPSI-8 showed good internal consistency (r = 0.67-0.80); association with existing FACT scales (e.g., FACT-P, Physical Well-being, Functional Well-being; r = 0.44-0.85, p <.0001), responsiveness to clinical change (Guyatt's Responsiveness statistic = 1.29), and ability to differentiate patients by performance status (p <.0001). A six-item alternate version of the FAPSI was also evaluated with comparable results.

CONCLUSIONS

This project produced a reliable and valid list of the eight most important clinician-rated targets of drug therapy for advanced prostate cancer. These questions perform comparably to the longer derivative questionnaire. Examination of patient agreement with this priority list and the extent to which changes in these 8 targets are related to meaningful clinical benefit to the patient are important next steps for future research.

[Chemotherapy of hormone refractory prostate carcinoma]

An increasing life expectancy and the growing number of largely healthy older men have lead to more patients with hormone insensitive relapses after palliative hormone or curative therapy for prostate cancer. After 10 years without therapeutic improvement for hormone refractory prostate cancer, the introduction of new substances has led to a revival of chemotherapy. Although a definitive cure is still not possible, such chemotherapy fulfils important palliative criteria-good toleration and an improvement in quality of life-in addition to distinct long-term remission. For example, taxane as a monotherapy or in combination with estramustine is effective and well tolerated while mitoxantrone in combination with prednisolone, although of limited effectiveness, leads to a substantial reduction in symptoms. Although evidence for increased longevity through modern chemotherapy is available, this has still not been definitively demonstrated. The substantial reduction in pain and therapy related morbidity frequently makes chemotherapy for hormone refractive prostate cancer a superior alternative to simple pain and complication management.

Randomized, double-blind, controlled trial of mitoxantrone/prednisone and clodronate versus mitoxantrone/prednisone and placebo in patients with hormone-refractory prostate cancer and pain

PURPOSE

To compare the incidence of palliative response in patients with hormone-resistant prostate cancer (HRPC) treated with mitoxantrone and prednisone (MP) plus clodronate with that of patients treated with MP plus placebo.

MATERIALS AND METHODS

Men with HRPC, bone metastases, and bone pain were randomly assigned to receive clodronate 1,500 mg administered intravenously (IV) or placebo every 3 weeks, in combination with mitoxantrone 12 mg/m2 IV every 3 weeks and prednisone 5 mg orally bid. Patients completed the present pain intensity (PPI) index and Prostate Cancer-Specific Quality-of-Life Instrument at each treatment visit and used a diary to record analgesic use on a daily basis. The primary end point was a reduction to zero or of two points in the PPI or a decrease of 50% in analgesic intake, without increase in either.

RESULTS

The study accrued 209 eligible patients over 44 months. One hundred sixty patients (77%) had mild PPI scores (1 or 2), and 49 (24%) had moderate PPI scores (3 or 4). The primary end point of palliative response was achieved in 46 (46%) of 104 patients on the clodronate arm and in 41 (39%) of 105 patients on the placebo arm (P =.54). The median duration of response, symptomatic disease progression-free survival, overall survival, and overall quality of life were similar between the arms. Subgroup analysis suggested possible benefit in patients with more severe pain.

CONCLUSION

MP provides useful palliation in symptomatic men with HRPC. Clodronate does not increase the rate of palliative response or overall quality of life. Clodronate may be beneficial to patients who have moderate pain, but this requires further confirmation.

The combination of estramustine and mitoxantrone in hormone-refractory prostate cancer: a phase II feasibility study conducted by the Hellenic Cooperative Oncology Group

OBJECTIVES

To consider the safety profile and therapeutic value of the combination of estramustine and mitoxantrone in a bimonthly schedule to treat hormone-refractory prostate cancer. The survival of patients with prostate cancer who relapse after androgen ablation is limited and the therapeutic options are restricted.

METHODS

Twenty-nine patients with relapse after previous treatment were included in the study; however, 3 patients who refused to start treatment were not included in the analysis, leaving 26 eligible patients. The median age was 64 years (range 44 to 82), the World Health Organization performance status ranged from 1 to 3, and the mean prostate-specific antigen level was 103 ng/mL (range 1 to 620). The Gleason score ranged from 2 to 9. The patients received a total of 208 therapeutic cycles (mean 8, range 3 to 24). Every cycle consisted of oral estramustine 140 mg, 3 times a day continuously, and intravenous mitoxantrone 20 mg (total dose). The regimen was repeated every 2 weeks.

RESULTS

Twenty-seven percent of patients with measurable soft-tissue disease demonstrated an objective response, which included one complete and six partial responses. Thirteen patients (50%) had a greater than 50% reduction in serum prostate-specific antigen level. The median duration of response was 9.2 months, and the median survival for all patients was 15 months. The most common side effects were neutropenia and thrombocytopenia.

CONCLUSIONS

The combination of estramustine and mitoxantrone is safe, well tolerated, and relatively active in patients with hormone-refractory prostate cancer. More patients are needed to partake in Phase III studies to establish the survival benefit that this combination may offer.

Early change in patient-reported health during lung cancer chemotherapy predicts clinical outcomes beyond those predicted by baseline report: results from Eastern Cooperative Oncology Group Study 5592

PURPOSE

To determine the ability of longitudinal patient-reported health (PRH) scores to enhance prediction of clinical outcomes beyond baseline scores.

PATIENTS AND METHODS

In 573 advanced non-small-cell lung cancer patients enrolled in a phase III clinical trial, we used baseline and 6-week follow-up PRH scores to predict best response to treatment, disease progression, and survival. Using regression analyses, we tested the predictive ability of the five subscales of the Functional Assessment of Cancer Therapy-Lung (physical, functional, social/family, emotional well-being, and the lung cancer subscale) as well as the trial outcome index (TOI) aggregate score.

RESULTS

After clinical factors were controlled for, baseline physical well-being (PWB) and TOI scores predicted all three clinical outcomes. A higher baseline PWB score was associated with a better response to treatment (odds ratio, 1.09; P <.001) and lower risk of death (risk ratio, 0.95; P <.001). Higher baseline TOI score was associated with a lower risk of disease progression (risk ratio, 0.98; P <.001). These two baseline predictors (PWB and TOI) were then used along with 6-week change scores to classify patients into four groups: low baseline-declined, low baseline-improved, high baseline-declined, and high baseline-improved. Patients with low baseline-declined PWB scores showed the worst responses to treatment and survived the shortest duration. Patients with low baseline-declined TOI scores had the shortest time to progression.

CONCLUSION

The physical aspects of baseline PRH and PRH change during chemotherapy are significant predictors of clinical outcomes in lung cancer. This has implications for patient stratification in clinical trials and may aid decision-making in clinical practice.

Phase III study of mitoxantrone plus low dose prednisone versus low dose prednisone alone in patients with asymptomatic hormone refractory prostate cancer

PURPOSE

We compared median time to treatment failure of men with asymptomatic, hormone refractory, progressive prostate cancer treated with mitoxantrone plus prednisone versus prednisone alone.

MATERIALS AND METHODS

In a multicenter phase III trial 120 men with asymptomatic, progressive, hormone refractory prostate cancer were randomly assigned to treatment with mitoxantrone and prednisone or prednisone alone. Patients received 12 mg./m. mitoxantrone intravenously once every 3 weeks for 6 cycles and 5 mg. prednisone twice daily with or without mitoxantrone. Time to treatment failure was assessed as an aggregate end point comprised of time to disease progression, time to toxicity or death, or time to initiation of alternate therapy.

RESULTS

Median followup was 21.8 months. Median time to treatment failure and median time to progression were the same: time to treatment failure and time to progression in the mitoxantrone and prednisone group was 8.1 months compared to 4.1 months in the prednisone alone group (p = 0.017 versus p = 0.018). More patients (27 or 48%) treated with mitoxantrone and prednisone achieved a 50% or greater reduction in prostate specific antigen levels than those who received only prednisone (15 or 24%, p = 0.007). There was no significant difference in median survival between the 2 groups, which was 23 and 19 months, respectively. Death was mainly attributable to disease progression.

CONCLUSIONS

Patients with hormone refractory prostate cancer who are asymptomatic but had progressive disease had a significantly higher response rate when treated with mitoxantrone and prednisone as demonstrated by the 50% or greater decrease in prostate specific antigen compared to treatment with prednisone alone. Time to treatment failure was significantly prolonged in the chemotherapy treated group but survival rates were not different.

Combining anchor and distribution-based methods to derive minimal clinically important differences on the Functional Assessment of Cancer Therapy (FACT) anemia and fatigue scales

Magnitude differences in scores on a measure of quality of life that correspond to differences in function or clinical course are called clinically important differences (CIDs). Anchor-based and distribution-based methods were used to provide ranges of CIDs for five targeted scale scores of the Functional Assessment of Cancer Therapy-Anemia (FACT-An) questionnaire. Three samples of cancer patients were used: Sample 1 included 50 patients participating in a validation study of the FACT-An; Sample 2 included 131 patients participating in a longitudinal study of chemotherapy-induced fatigue; sample 3 included 2,402 patients enrolled in a community-based clinical trial evaluating the effectiveness and safety of a treatment for anemia. Three clinical indicators (hemoglobin level; performance status; response to treatment) were used to determine anchor-based differences. One-half of the standard deviation and 1 standard error of measurement were used as distribution-based criteria. Analyses supported the following whole number estimates of a minimal CID for these five targeted scores: Fatigue Scale = 3.0; FACT-G total score = 4.0; FACT-An total score = 7.0; Trial Outcome Index-Fatigue = 5.0; and Trial Outcome Index-Anemia = 6.0. These estimates provide a basis for sample size estimation when planning for a clinical trial or other longitudinal study, when the purpose is to ensure detection of meaningful change over time. They can also be used in conjunction with more traditional clinical markers to assist investigators in determining treatment efficacy.