Phase II study of estramustine, oral etoposide, and vinorelbine in hormone-refractory prostate cancer

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.

Phase II study of sequential chemotherapy with docetaxel-estramustine followed by mitoxantrone-prednisone in patients with advanced hormone-refractory prostate cancer

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

New standards in the chemotherapy of metastatic hormone-refractory prostate cancer

Hormone-refractory prostate cancer (HRPC) is a major issue in Western countries and the second leading cause of cancer death in North American men. In the prostate-specific antigen era, most HRPCs are currently diagnosed in asymptomatic patients based on biochemical failure, with increasing demand for active treatment. Until recently, chemotherapy for HRPC patients was not considered a standard of care due to the absence of clear data evidencing an overall survival benefit. In fact, few Phase III studies conducted in the 1980s and early 1990s had documented a superiority over corticosteroids alone in terms of biochemical response (declines in serum prostate-specific antigen levels) and quality of life, but not survival. Due to their impact on pain control, mitoxantrone and prednisone were long considered the best regimen for symptomatic HRPC patients. In recent years, more chemotherapeutic agents have been tested, among which the microtubule inhibitors (vinca alkaloids and taxanes) have obtained the most promising results in Phase II trials and have entered Phase III testing. Two well-designed randomized trials have changed this scenario. Both compared docetaxel (with or without estramustine) against mitoxantrone and prednisone, and demonstrated a significant advantage not only in terms of response, pain control and quality of life, but also in terms of overall survival. Which patients need to be treated, the regimen of choice and duration of chemotherapy will be the next questions to be answered in the coming years in the field of HRPC, along with the role of new signal transduction inhibitors and other targeted therapies.

Weekly docetaxel and vinorelbine (VIN-DOX) as first line treatment in patients with hormone refractory prostate cancer

BACKGROUND

The current study investigated the clinical benefit, the impact on biochemical and objective response and tolerability of weekly docetaxel with vinorelbine (VIN-DOX) in symptomatic patients with hormone refractory prostate cancer (HRPC).

METHODS

Patients were treated with docetaxel 25 mg/m2 and vinorelbine 20 mg/m2, intravenously for 6 consecutive weeks followed by a 2 week rest repeatedly until disease progression. Clinical benefit evaluations, based on Karnofsky performance status (KPS) and pain measure, were assessed weekly during therapy. A clinical benefit response was defined as a sustained (> or =4 weeks) improvements in one of these parameters. Changes in prostate-specific antigen (PSA) levels, tumoral response and toxicity also were evaluated.

RESULTS

19 men (median age 68 years), were treated. Overall, 42% of patients achieved a KPS significant change and positive pain response; 47% achieved a 50% or greater reduction in PSA. The objective response rate was observed in 2 of 9 patients with measurable disease (22%). The most important toxicity was neutropenia (Grade 3 = 32%).

CONCLUSIONS

The combination of weekly VIN-DOX appears to be feasible. VIN-DOX was found to be associated with improvement in clinical benefit response and biochemical response and well tolerated as first line treatment in HRPC.

A phase II study of vinorelbine and estramustine in patients with hormone-resistant prostate cancer

INTRODUCTION

This phase II study was designed to evaluate the efficacy of vinorelbine in combination with estramustine in patients with chemotherapy-naïve hormone-refractory prostate cancer.

MATERIAL AND METHODS

Patients received vinorelbine (i.v. 25 mg/m2) on days 1 and 8 every 3 weeks and estramustine (oral, 600 mg/m2) daily. Eligible patients were required to have progressive metastatic disease following the first hormonal manipulation.

RESULTS

Of the 51 patients enrolled (median age = 69 years), 84% presented bone involvement and 75% had at least two organs involved at the time of study entry and 47 were evaluable for treatment efficacy. Prostate specific antigen (PSA) response (> or =50% decrease) which was the primary efficacy criterion was reported in 21 patients (41.2%) in the intent-to-treat (ITT) population and in 20 patients (48.8%) in the per protocol (PP) population. Of the 7 patients with measurable disease, 2 achieved partial response. Median progression-free survival and overall survival were 4.7 months (range: 1.9-8.6) and 14.3 months (range: 4.2-21.2), respectively. Grade 3-4 neutropenia was reported in 6.1% of patients and in 1% of cycles. The incidence of complicated neutropenia (febrile neutropenia reported in 1 patient and septic shock with severe neutropenia reported in 2 patients) was 5.8%. The most frequent grade 3-4 non-haematological events (% of patients > or =5%) included anorexia (10%), thrombosis/embolism (8%), vomiting and hypotension (6% each). There were 3 toxic deaths (5.9 %) resulting from pulmonary embolism, angina pectoris, and septic shock. The impact of combined chemotherapy on the quality-of-life (QL) of the patients was assessed between baseline and the first evaluation scheduled at 6 weeks indicated a marked reduction in pain while the rest of the symptoms remained stable. Overall, health status improved slightly over the treatment period.

CONCLUSIONS

This study confirmed that the combination of vinorelbine and estramustine is an active regimen in patients with hormone-resistant prostate cancer who had not been treated previously with chemotherapy. Main toxicities included complicated neutropenia even though the incidence of severe neutropenia was low. We observed a higher incidence of toxic deaths which could have been related to the regimen of estramustine used in the study.

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.

Thromboembolic events with estramustine phosphate-based chemotherapy in patients with hormone-refractory prostate carcinoma: results of a meta-analysis

BACKGROUND

Combinations of cytotoxic chemotherapy with estramustine phosphate (EMP), a nornitrogen mustard-estrogen conjugate, are used to treat patients with hormone-refractory prostate carcinoma (HRPC). However, thromboembolic events (TE), including deep venous thrombosis (DVT), pulmonary embolism, stroke, myocardial infarction, and arterial thrombosis, are significant toxicities of these regimens. The current study sought to establish the rate of TE and to determine risk factors for TE.

METHODS

A MEDLINE-based search identified EMP-based clinical trials published in the English-language peer-reviewed literature after 1990 in which > or = 20 patients with HRPC were enrolled and TE were clearly documented. Patient characteristics and the dose of EMP given were analyzed to determine their association with the rate of TE.

RESULTS

Twenty-three studies, enrolling a total of 896 patients, were included in the analysis. The overall risk of TE was 0.07 (95% confidence interval [95% CI], 0.05-0.11). The risk of DVT was 0.06 (95% CI, 0.04-0.09). The risks of all other types of TE were <0.01. Using univariate logistic regression analysis, the dose of EMP administered, baseline patient age, and baseline prostate-specific antigen level were not found to be associated with the total risk of TE. The rates of total TE and DVT may be inflated because one of the analyzed studies initially had a very high rate of DVT (25%) when compared with the others.

CONCLUSIONS

The rate of TE in men with HRPC who are treated with EMP-based regimens is significant, but it does not appear to be related to the dose of EMP. Whether TE can be prevented with anticoagulant prophylaxis remains to be determined.

Mitoxantrone, vinorelbine and prednisone (MVD) in the treatment of metastatic hormonoresistant prostate cancer — a phase II trial

A total of 28 patients were treated with mitoxantrone, vinorelbine and prednisone every 3 weeks. In all, 11 patients (46%) had a significant prostate-specific antigen decline for a median duration of 11.4 months. Eight patients (33%) achieved a partial response on pain, while seven (29%) obtained a stabilisation of the symptom. Median duration of the response was 9.5 months. A confirmed partial response was obtained in three out of seven patients who had bidimensionally measurable disease. Toxicity was manageable. Our study provides further support to the concept of combined antimicrotubule therapy for metastatic harmonoresistant prostate cancer, promoting the exploration of new regimens containing antimicrotubule agents in addition to mitoxantrone-prednisone.

Prostate cancer and bone metastases: medical treatment

Prostate cancer is the most common malignancy in men in the United States. With the long natural history of the disease, management of skeletal morbidity related to advanced prostate cancer becomes a major public health issue. The standard of care in advanced prostate cancer is androgen deprivation therapy. This may accelerate the development of osteoporosis and further exacerbate the risks of having adverse skeletal-related events develop. Recently, the use of bisphosphonates in men who have not responded to androgen deprivation therapy has been shown to reduce the incidence of skeletal-related events with time. Questions remain as to whether bisphosphonates should be broadly applied to earlier stages of the disease or tailored to men at higher risk of having bone-related morbidity. Work is ongoing to improve other approaches to the medical treatment of bone metastases in patients with advanced prostate cancer including the use of radiopharmaceuticals and combined chemotherapy.

Optimizing targeted therapy and developing novel outcome measures for patients with advanced prostate cancer at Memorial Sloan-Kettering Cancer Center

Hormonal therapy and chemotherapy, though active treatments for prostate cancer, are not curative for patients with metastatic disease. Targeted therapy has the potential to control, if not eradicate, cells resistant to castration and chemotherapy. Despite several years of development, however, a biologic approach with clear clinical benefits has yet to emerge from a crowded field. This review outlines the approaches being studied at Memorial Sloan-Kettering Cancer Center to optimize biologic therapy. Trials of targeted therapy are designed on the basis of a clinical states model that describes both patient clinical risks and tumor biology. Drugs that act on multiple pathways are being developed, and targets that are expressed across all phases of the disease are selected. New molecular imaging techniques permit assessments of the target before, during, and after treatment. High-throughput preclinical assays of gene expression are being developed to enhance selection of drug sequences and combinations for clinical testing.

Current strategies in the management of hormone refractory prostate cancer

Prostate cancer is the most common cancer diagnosed in American males, and is the second leading cause of cancer-related deaths. Most patients who develop metastatic disease will initially respond to androgen deprivation, but response is invariably temporary. Most patients will develop androgen-independent ("hormone-refractory") disease that results in progressive clinical deterioration and ultimately death. This progression to androgen independence is accompanied by increasingly evident DNA instability and alterations in genes and gene expression, including mutations in p53, over-expression of Bcl2, and mutations in the androgen receptor gene, among others. Treatment options for hormone refractory disease include intensive supportive care, radiotherapy, bisphosphonates, second-line hormonal manipulations, cytotoxic chemotherapy and investigational agents. A post-treatment reduction in the level of prostate specific antigen (PSA) by 50% has been shown to correlate with survival and has been accepted by consensus as a valid endpoint in clinical trials. Chemotherapeutic agents such as mitoxantrone, estramustine, and the taxanes have yielded improved response rates and palliative benefit, but not improved survival. Therefore, current efforts must be focused on enrolling patients onto clinical trials of investigational agents with novel mechanisms of action, and on using survival, time to progression, and quality of life as end points in routine clinical practice.

The rationale for adjuvant chemotherapy for high-risk prostate cancer

PURPOSE OF REVIEW

With the advent of prostate-specific antigen, stage migration has resulted in a shift towards early-stage prostate cancer at diagnosis. Although radical prostatectomy and radical radiotherapy can be curative in organ-confined disease, there remains a significant proportion of early-stage patients who go on to develop progressive, incurable disease. This review will highlight developments in the identification of high-risk patients, and summarize the results of investigations of adjuvant chemotherapy in this setting.

RECENT FINDINGS

The ability to identify patients at high risk of developing progressive disease is improving. Both preoperative and postoperative variables, as well as newer radiographic and molecular tools, can identify at-risk patients who may benefit from adjuvant therapy. Coupled with developments in chemotherapeutic agents for prostate cancer, this provides the rationale for investigating chemotherapy in this setting. Unfortunately, to date, reported trials involving adjuvant chemotherapy in prostate cancer are few, and generally involve small numbers of patients. Some of the studies confirm that certain populations of patients, such as those with node-positive disease, may benefit from systemic therapy. Definitive data, however, will be derived from ongoing randomized trials investigating adjuvant chemotherapy.

SUMMARY

Although definitive data regarding systemic chemotherapy in adjuvant therapy are scarce, the results of the available studies, and the increasing accuracy in delineating the population at risk, have laid the foundation for future and ongoing studies in this area.

Chemotherapy for prostate cancer

Androgen deprivation therapy remains the mainstay of therapy for patients with advanced prostate cancer and for selected patients with localized prostate cancer. Androgen deprivation therapy is the model of target-based therapies in this disease. Although it is clear that other target-based therapies need to be developed, cytotoxic chemotherapy is emerging as an effective form of treatment for men with prostate cancer. The early studies combining mitoxantrone plus a corticosteroid demonstrated that chemotherapy could be given to men with symptomatic hormone-refractory prostate cancer with minimal toxicity, and significant palliation could be provided. Since then, it has been recognized that estramustine, when combined with a variety of microtubular inhibitors, is very active in hormone-refractory prostate cancer. Doublets combining estramustine plus a taxane seem to be the most active. Although it appears that estramustine may add some activity to taxanes, the mechanism of its activity is uncertain, and its overall value is similarly questioned, particularly in light of its significant toxicity. Regimens that omit estramustine are being explored (ie, either taxane alone or taxane plus biologic agents). In addition, triplet therapy (combining estramustine plus a taxane plus a third drug, such as carboplatin or etoposide) is being explored. Finally, the utility of chemotherapy is beginning to be explored in the context of earlier disease in the neoadjuvant, adjuvant, or serologically relapsing group of patients. Data from these studies are just beginning to be gathered.

Vinorelbine in androgen-independent metastatic prostatic carcinoma--a phase II study

The purpose of this study was to evaluate the efficacy of vinorelbine treatment in terms of prostate-specific antigen (PSA) response and clinical benefit (decrease of pain or analgesic score for the subgroup of patients with pain), as well as its toxicity in patients with progressive metastatic androgen-independent prostatic carcinoma. 44 patients with prostatic carcinoma progressing after orchiectomy or during treatment with hormonal agents were treated with vinorelbine at a dose of 30 mg/m(2) intravenously (i.v.) on days 1 and 8 of a 21-day cycle. Inclusion criteria were metastatic progressive prostatic carcinoma with prostate-specific antigen (PSA) serum levels >/=3 x upper limit of normal, World Health Organization (WHO) performance status </=2, age <85 years and adequate bone marrow, liver and renal functions. Treatment was continued until progression or a maximum of 12 cycles. Treatment was delayed for a week if haematological toxicity grade >/=2 was observed on the day of scheduled vinorelbine administration. 9 patients received less than three cycles, 6 due to rapid tumour progression. Treatment at day 1 had to be delayed in 13.7% of 183 cycles. Treatment at day 8 had to be omitted in 19.7% of all cycles. Grade >/=3 granulocytopenia occurred in 18% of patients. 4 patients had severe constipation. In 7 patients (15.9%, Confidence Interval (CI) 6.6-30.1%), a PSA response (>/=50% reduction of PSA levels) was observed. Among 8 patients with measurable disease, 3 had partial remission and 1 no change. Median time to PSA progression in 43 assessable patients was 11.9 weeks (range 3-52 weeks). Median duration of PSA response was 14 weeks (9-30 weeks). Clinical benefit was seen in 7 of 31 cases (23%) with baseline pain, there was no association with PSA response. Vinorelbine is a fairly well tolerated drug with a moderate single agent activity in patients with androgen-refractory prostate cancer.

A phase II Hoosier Oncology Group study of vinorelbine and estramustine phosphate in hormone-refractory prostate cancer

BACKGROUND

The purpose was to evaluate the combined anti-microtubular regimen of vinorelbine and estramustine phosphate (EMP) in hormone refractory prostate cancer.

PATIENTS AND METHODS

Weekly vinorelbine 20 mg/m2 (or 15 mg/m2 if a history of prior pelvic radiotherapy) was combined with EMP at 280 mg orally tds for 3 days (the day before, the day of and the day after vinorelbine infusion). After 8 weeks of therapy the combination was given every other week.

RESULTS

From February 1998 to February 1999, 23 men were enrolled with a median age of 69 years (range 50-83 years). The median prostate-specific antigen (PSA) at entry was 160 ng/ml (range 0-802 ng/ml). A median of 13 weeks of therapy was administered and the median follow-up was 14.8 months. Eleven patients (48%) had lower extremity edema requiring diuretic therapy, two (9%) had grade 2 granulocytopenia and four patients [17%; 95% confidence interval (CI) 5% to 39%] had a thromboembolic episode. There was no treatment-related mortality. Fifteen of 21 patients (71%; 95% CI 49% to 89%) had at least a 50% decrease in the PSA for at least 2 months with a median time to serologic progression of 3.5 months (range 0.75-10.5 months). One of eight patients (12.5%; 95% CI 0% to 53%) with measurable disease had a confirmed partial response. The estimated median survival was 15.1 months and the actual one year overall survival was 71% (95% CI 51% to 88%).

CONCLUSIONS

Weekly vinorelbine with short course oral EMP is an active regimen as evaluated by rate of PSA response, time to progression and median survival. However, the toxicities of EMP, even when given as a short course, are still problematic.

Treatment options in hormone-refractory prostate cancer: current and future approaches

Prostate cancer is the second leading cause of cancer mortality among men in Western countries. The initial treatment of advanced prostate cancer is suppression of testicular androgen production by medical or surgical castration, but nearly all men with metastases will develop disease progression. Patients with hormone refractory prostate cancer (HRPC) have a median survival of approximately 18 months and no therapy has yet demonstrated a definitive survival advantage. However, in the past several years, a number of promising new treatment strategies have emerged. One of the most important new treatment strategies involves secondary hormonal manipulation after the failure of primary androgen deprivation. This approach is predicated on the recognition that HRPC is a heterogeneous disease and some patients may respond to alternative hormonal interventions despite the presence of castrate levels of testosterone. Until recently, cytotoxic chemotherapy was felt to be relatively ineffective in the treatment of HRPC. Combination regimens incorporating new active agents have demonstrated significant activity in this setting, renewing interest in the use of chemotherapy to treat HRPC. Recent advances in the understanding of prostate cancer biology have led to the development of drugs directed against precise molecular alterations in the prostate tumour cell. Biologic agents now in development include those capable of altering signal transduction, blocking angiogenesis, inhibiting cell cycle progression, and stimulating apoptosis. In addition, many types of immune therapies are showing promise. Evaluating these agents, and incorporating them into existing regimens, are major goals of ongoing clinical research in advanced prostate cancer.

Developments in cytotoxic chemotherapy: advances in treatment utilising vinorelbine

Vinorelbine is a third generation vinca alkaloid which has been in clinical development for 15 years. Recent exploration of its pre-clinical activity has revealed unexpected evidence of potential synergy with taxane compounds and early clinical results support the suggestion of enhanced efficacy particularly in breast cancer. The initial studies establishing the clinical activity of vinorelbine in breast cancer and non-small cell lung cancer have been extended to encompass a thorough evaluation of its contribution to combination chemotherapy for these disorders. In the treatment of breast cancer useful activity has been established for vinorelbine in combination with anthracyclines, anthracenediones, antimetabolites and the taxanes; additive toxicity is not a limiting factor. The activity of vinorelbine in the treatment of non-small cell lung cancer is significantly extended by incorporation into schedules utilising cisplatin and other agents. Vinorelbine has also demonstrated useful activity in the treatment of a wide range of other malignancies including prostatic carcinoma, multiple myeloma, cancer of the ovary, cervix and head and neck and malignant lymphomas.

Oral combination of cyclophosphamide, uracil plus tegafur and estramustine for hormone-refractory prostate cancer

OBJECTIVE

To evaluate the clinical usefulness of an oral combination of cyclophosphamide, uracil plus tegafur (UFT) and estramustine in the treatment of patients with hormone-refractory prostate cancer (HRPC).

METHODS

Twenty-one patients were treated with oral administration of cyclophosphamide (100 mg/day), UFT (400 mg/day) and estramustine phosphate (560 mg/day). The median age of the patients was 70 years. Twelve patients had symptomatic bone metastasis, 6 had asymptomatic bone metastasis, 5 had lymph node metastasis, while 2 had only biochemical progression evaluated by prostate-specific antigen (PSA).

RESULTS

Twelve (57%) out of 21 patients showed a PSA decline of 50% or greater. The median response duration was 7 months (range 2-15 months). Among the 20 patients assessable for bone pain, 2 (10%) improved, 12 (60%) remained stable and 6 (30%) progressed. Among the 10 patients assessable for bone metastasis, 1 (10%) improved, 5 (50%) were stable and 4 (40%) progressed on bone scan. Among 3 patients assessable for measurable disease (lymph node metastasis), 2 (67%) showed partial response and 1 (33%) progression. Most toxicities were mild.

CONCLUSIONS

The combination of cyclophosphamide, UFT and estramustine is an active and well-tolerated regimen for HRPC. To evaluate the survival benefit, further randomized studies are required.

Chemotherapy in advanced androgen-independent prostate cancer 1990-1999: a decade of progress?

BACKGROUND AND PURPOSE

A great number of clinical research studies have been reported in the field of chemotherapy for advanced androgen-independent prostate cancer during the last ten years. The aims of the present review were to assess their impact on management of the disease and on survival of patients.

METHODS

The review of full published reports was facilited by the use of a MEDLINE computer search.

RESULTS

Clinical research studies have focused on defining guidelines for eligibility criteria and accurate endpoints for patients to be enrolled onto clinical trials and developing new agents or combination of drugs including estramustine phosphate. Any combination of current chemotherapy has no impact on overall survival of patients. Among drugs in development, only the promising activity observed with docetaxel deserves randomized trials to assess its impact on survival. The major innovative advance of the 90s is the demonstration of the impact of chemotherapy (mitoxantrone + prednisone) on quality of life as compared to prednisone alone. A greater and longer-lasting improvement in quality of life along with a concomitant decrease in costs was observed.

CONCLUSIONS

At the present time, chemotherapy should be considered as a palliative treatment in patients with symptomatic androgen-independent disease. The enrollment of patients into clinical trials dealing with quality of life as primary endpoint is strongly solicited. A standard methodology should be used in phase II trials with a primary goal of selection of agents which should progress to randomized trials using survival as an endpoint. Hopefully new specific strategies targeted to reverse the molecular changes that underlie prostate tumorigenesis should rapidly impact the multimodality management of AIPC in the third millenium.

Vinorelbine and estramustine in androgen-independent metastatic prostate cancer: a phase II study

BACKGROUND

The aim of this study was to determine the safety and activity of vinorelbine in combination with estramustine in men with androgen-independent metastatic prostate cancer.

METHODS

Twenty-five men with androgen-independent metastatic prostate cancer were treated with the combination of vinorelbine and estramustine. Vinorelbine 25 mg/m(2) was administered by intravenous bolus on Days 1 and 8. Estramustine 140 mg was administered three times a day by mouth on Days 1 through 14. Treatment was repeated every 21 days.

RESULTS

A total of 132 cycles of treatment were administered. The median number of cycles per patient was 5 (range: 1-16). Mild Grade 1 or 2 gastrointestinal toxicity and fatigue were the most common adverse effects. Hematologic toxicity was minimal. Treatment resulted in a sustained > 50% decrease in serum prostate-specific antigen (PSA) in 6 of 25 patients (24% of patients; 95% confidence interval (CI) 9-45%). The median duration of PSA response was 10 weeks (range: 3-39 weeks). Of the five men with bidimensionally measurable disease, none achieved a complete or partial response. There were no documented improvements in post-treatment bone scans. Median overall survival time was 14.1 months.

CONCLUSIONS

The combination of vinorelbine and estramustine is a well-tolerated and modestly active regimen in men with androgen-independent metastatic prostate cancer.

Oral estramustine phosphate and oral etoposide for the treatment of hormone-refractory prostate cancer

BACKGROUND

The purpose of the present study was to evaluate the antitumor activity and toxicity of oral estramustine phosphate (EMP) in combination with oral etoposide in patients with hormone-refractory prostate cancer.

METHODS

Twenty patients with adenocarcinoma of the prostate that progressed after one or more regimens of androgen-deprivation therapy were enrolled into this trial. Oral EMP was administered twice daily, for a total daily dose of 560 mg, and oral etoposide (50 mg/bodyweight per day) was given on days 1-21 and was stopped on days 22-35. Treatment was continued until evidence of disease progression appeared or two consecutive rises in the prostate-specific antigen (PSA) value were observed.

RESULTS

Ten of 20 patients showed a decrease of 50% or greater in the PSA value from initially elevated PSA levels after therapy. The median progression-free duration and 2 year cause-specific survival rate of these 10 patients were 208 days (range 71-693 days) and 67.5%, respectively. There were no significant differences in age, pretreatment PSA value, duration from initial treatment to relapse, prior therapy or survival between patients who had a decrease of 50% or greater in PSA values after this combination therapy and those who did not. The main toxicities (> or =grade 2) were anemia, leukocytopenia, thrombocytopenia, gastrointestinal and hepatic disorders, which occurred in 40, 15, 10, 15 and 5% of patients, respectively.

CONCLUSIONS

The combination of oral EMP and etoposide is considered to be a well-tolerated outpatient treatment regimen for patients with hormone-refractory prostate cancer and the therapy deserves further investigation.

Suramin in combination with weekly epirubicin for patients with advanced hormone-refractory prostate carcinoma

BACKGROUND

Suramin and epirubicin are both active agents in the treatment of patients with hormone-refractory advanced prostate carcinoma, with demonstrated antitumor synergism in vitro on human prostate carcinoma cells and different dose-limiting toxicities. The authors conducted this Phase II study to determine the feasibility, toxicity, and antitumor activity of suramin in combination with epirubicin.

METHODS

Only patients with hormone-independent advanced prostate carcinoma who had progressive disease after the last therapeutic maneuver they had undergone, including antiandrogen withdrawal, entered the study. Suramin was administered initially as a 6-day continuous infusion for 10 consecutive weeks and then for 6 days every 28 days for a maximum of 6 months. Doses were determined by a computer-assisted dosing system that used Bayesian pharmacokinetics to maintain suramin plasma concentrations of 200-250 microg/mL. Cortisone acetate 25 mg, administered at 8 a.m. and 8 p.m. daily, was begun 4 weeks after the initiation of suramin therapy. Epirubicin 25 mg/m2 was given as a weekly intravenous bolus beginning on Day 1 and was continued for a maximum of 6 months.

RESULTS

Twenty-six patients entered the study. Toxicities mainly included World Health Organization Grade 1-2 nausea, fatigue, anorexia, neutropenia, peripheral neuropathy, creatinine elevation, proteinuria, and prolonged prothrombin time, whereas Grade 3 toxicities were uncommon. Among 11 patients with measurable disease, 3 (27%) demonstrated an objective response. Among 24 patients evaluated for prostate specific antigen (PSA) response, 8 (33%; 95% confidence interval 16-55%) had a > or =50% decrease in PSA levels, which lasted a median of 32 (range, 8-52) weeks. Median progression free and overall survival were both 8 months.

CONCLUSIONS

The combination of suramin and epirubicin used in the current study is feasible, is associated with moderate toxicities, and has antitumor activity in advanced hormone-refractory prostate carcinoma. However, the results obtained with this combination do not represent major improvements in the treatment of patients with this disease, compared with suramin or epirubicin alone or other available treatments.

Recent advances in the treatment of prostate cancer

As new evidence for prostate cancer treatment has emerged in the last few years, longstanding controversies in the treatment of prostate cancer have resurfaced. A number of long-held tenets of prostate cancer therapy have been revisited, sometimes with surprising and challenging results. Although neoadjuvant hormonal therapy prior to radical prostatectomy decreases positive surgical margin rates, longer follow-up is needed to support survival improvement of this combined modality therapy. Androgen deprivation combined with radiation therapy appears to improve disease-free survival (and survival in one series) in patients with locally advanced cancer. Another approach to locally advanced prostate cancer using three-dimensional conformal radiation therapy may improve long term outcome. The data are currently insufficient to conclude that interstitial low dose rate brachytherapy is equivalent to conventional treatments: patients with small tumor volumes and low Gleason grade seem to obtain more benefit, whereas for large tumors with higher gleason grades this approach seems inferior to conventional treatments. In advanced prostate cancer recent data suggest that immediate hormonal therapy improves survival. In this group of patients the use of maximum androgen blockade remains controversial but may adversely affect quality of life compared to orchiectomy alone. Intermittent hormonal therapy may improve quality of life, although effect upon survival is unknown. Chemotherapy in combination with androgen deprivation is currently being studied as front-line therapy in advanced prostate cancer. Palliative benefit of chemotherapy for hormone refractory prostate cancer remains an important endpoint; survival advantage has not been seen in any randomized trials. Suramin may delay disease progression in hormone refractory prostate cancer. Many aspects of prostate cancer treatment will remain controversial until results of large, randomized trials with longer follow-up are available.

A phase II trial of irinotecan in hormone-refractory prostate cancer

Irinotecan is a DNA topoisomerase I inhibitor that has a wide spectrum of activity against human tumors in both preclinical and clinical studies. To evaluate the efficacy of irinotecan in hormone-refractory prostate cancer, we conducted a phase II study in 15 men with metastatic, PSA-progressive disease after primary androgen deprivation. Irinotecan was administered at a dose of 125 mg/m2 weekly for four weeks followed by a two-week rest period; cycles were repeated every six weeks. Response was assessed by evaluation of serial changes in the serum PSA. None of fifteen patients had a decline in PSA of greater than 50%; eight patients had stable disease as a best response. None of three patients with measurable disease had a partial or complete response. Toxicity was primarily hematologic and gastrointestinal, with 40% of patients requiring dose modification due to granulocytopenia and 20% requiring intravenous fluid supplementation after development of diarrhea. There were no treatment-related deaths. We conclude that irinotecan in the dose and schedule used in this trial does not have significant activity against hormone-refractory prostate cancer.

Chemotherapy for hormone refractory prostate cancer

New combinations have been developed that show significant activity in therapy for hormone refractory prostate cancer. Several of these are designed to address specific cellular targets unique to prostate cancer. To date, the major benefits of these therapies have been palliative in nature, resulting in an improvement in quality of life, particularly with the combination of mitoxantrone and prednisone. None of these agents or regimens have been shown to affect survival significantly, and none can be considered to be standard therapy for this disease. Nonetheless, the success of these regimens in inducing response has challenged the skepticism concerning the appropriateness of chemotherapy for patients with advanced prostate cancer. The ability to slow and even reverse the growth of far advanced disease raises the possibility that the application of these regimens earlier in the course of the disease will have a more significant impact on the morbidity and, in the long run, on the mortality of prostate cancer. It is hoped that the enrollment of patients into properly designed clinical trials of new agents and combinations will result in the development of therapy with proven efficacy in the near future.