An active regimen of weekly paclitaxel and estramustine in metastatic androgen-independent prostate cancer

Bone-targeted therapy: phase II study of strontium-89 in combination with alternating weekly chemohormonal therapies for patients with advanced androgen-independent prostate cancer

OBJECTIVES

Bone-targeted therapy that combines strontium-89 (Sr-89) with alternating weekly chemohormonal therapy may improve clinical outcomes in patients with metastatic hormone-refractory prostate cancer. This phase II study investigated the addition of Sr-89 to an alternating weekly regimen of doxorubicin and ketoconazole with paclitaxel and estramustine in patients with progressive prostate cancer and bone involvement.

METHODS

Twenty-nine patients with progressive adenocarcinoma of the prostate and osteoblastic bone metastases who failed conventional hormonal therapy were registered for the study. Of those, 27 were treated with Sr-89 on day 1 of week 1. On weeks 1, 3, and 5, patients received doxorubicin (20 mg/m on day 1) and oral ketoconazole (400 mg 3 times a day for 7 days). On weeks 2, 4, and 6, patients received paclitaxel (100 mg/m(2)) and oral estramustine (280 mg 3 times a day for 7 days). No treatment was given during weeks 7 and 8. Cycles were repeated every 8 weeks.

RESULTS

A > or =50% reduction in prostate-specific antigen level was maintained for at least 8 weeks in 77.7% of the patients (21 patients) at 16 weeks and in 66.6% (18 patients) at 32 weeks. The median progression-free survival was 11.27 months (range, 1.83-29.53), and the median overall survival was 22.67 months (1.83-57.73+). Two patients died during study because of disease progression. Overall, the chemotherapy combined with Sr-89 was well tolerated.

CONCLUSIONS

Our results demonstrate that the combination of alternating weekly chemohormonal therapies with Sr-89 demonstrates a prolonged progression-free and overall survival with acceptable toxicity. Further investigation of combination therapies with Sr-89 is warranted.

Systemic nonhormonal management of advanced prostate cancer and its likely impact on patients' survival and quality of life

Prostate cancer is a hormonal sensitive disease with a response rate ranging from 80 to 90%; however, the majority of patients develop hormone resistance resulting in poor long term survival. Chemotherapy has demonstrated a benefit over steroids in improving the quality of life in the hormone refractory phase. Furthermore, the introduction of docetaxel succeeded in improving the survival of these patients in first-line therapy. Second-line treatment following docetaxel is challenging with no agent classified as standard in this setting. In the last 5 years, several drugs have shown promising results in initial evaluation. However, randomized phase III trials would be needed to answer this question. The majority of patients develop bone metastasis and the use of bisphosphonates has yielded encouraging results. Our understanding of the biology of hormone refractory prostate cancer has improved dramatically over the past few years and has translated into the developments of new therapeutic targets for this disease. Agents affecting several targets, including calcitriol, endotheline-1, bcl-2, and angiogenesis, are being studied currently and have the potential to change the treatment paradigms of this otherwise fatal disease. This review focuses on current and potential treatment options, including cytotoxic agents, bisphosphonates, and targeted agents, for patients with hormone refractory prostate cancer and the impact of these options on survival and quality of life.

Assessing outcomes in prostate cancer clinical trials: a twenty-first century tower of Babel

BACKGROUND

Because of the osseous distribution of prostate cancer metastases, progression is more readily identified than response in prostate cancer clinical trials. As a result, there is an increased focus on progression-free survival (PFS) as a phase 2 endpoint. PFS, however, is vulnerable to inter-study design variability. The authors sought to identify and quantify this variability and the resultant error in PFS across prostate cancer clinical trials.

METHODS

The authors reviewed phase 2 clinical trials of cytotoxic agents in castration-resistant metastatic prostate cancer over 5 years to evaluate the policies determining extent of disease and the definitions of disease progression. A simulation model was created to define the degree of error in estimating PFS in 3 hypothetical cohorts (median PFS of 12, 24, and 36 weeks) when the frequency of outcome assessments varies.

RESULTS

Imaging policies for trial entry were heterogeneous, as were the type, timing, and indications for outcome assessments. In the simulation, error in the reported PFS varied according to the interval between assessments. The difference between the detected and the true PFS could vary as much as 6.4 weeks per cycle, strictly resulting from the variability of assessment schedules tested.

CONCLUSIONS

Outcome assessment policies are highly variable in phase 2 studies of castration-resistant prostate cancer patients, despite published guidelines designed to standardize authentication of disease progression. The estimated error in PFS can exceed 6 weeks per cycle, exclusively because of variations in the assessment schedules. Comparisons of PFS times from different studies must be made with circumspection.

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

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

Pre-clinical and clinical evaluation of estramustine, docetaxel and thalidomide combination in androgen-independent prostate cancer

OBJECTIVE

To evaluate the combination of docetaxel plus estramustine (which prolongs survival in patients with androgen-independent prostate cancer, AIPC), and thalidomide (that also adds to docetaxel activity), both pre-clinically and clinically in AIPC.

PATIENTS, MATERIALS AND METHODS

In the pre-clinical evaluation we injected PC3 cells subcutaneously into severely combined immunodeficient mice and started treatment after the tumour volume reached 50 mm3. We also evaluated the combination using luciferase-labelled PC3M-luc-C6 cells in nude mice. We enrolled 20 patients with metastatic progressive AIPC into a phase II clinical trial to evaluate this combination. Docetaxel (30 mg/m2) was administered every week, for 3 of 4 weeks. The dose of thalidomide was 200 mg/day and estramustine was given three times a day at 1, 2, 3, 8, 9, 10, 15, 16 and 17 days.

RESULTS

In the mice, thalidomide with docetaxel plus estramustine reduced tumour volume by 88% at 17 days vs the control treatment (p=0.001). The combination of docetaxel, estramustine and thalidomide nearly eradicated the signal from the luciferase-expressing PC3M cells in the metastasis model. Clinically, the progression-free time was 7.2 months with this combination; 18 of 20 patients had a decline of half or more in prostate-specific antigen level and two of 10 patients with soft-tissue lesions had a partial response on computed tomography. There were 24 grade 3 and two grade 4 complications associated with this combination. There was a statistically significant association between overall survival and the CYP1B1*3 genotype (P=0.013).

CONCLUSION

Docetaxel-based chemotherapy is now regarded as a standard regimen for metastatic AIPC. The combination of estramustine, docetaxel and thalidomide is an advantageous treatment in pre-clinical models of prostate cancer and is a safe, tolerable and active regimen in patients with AIPC.

Phase II study of low-dose docetaxel/estramustine in elderly patients or patients aged 18-74 years with hormone-refractory prostate cancer

PURPOSE

Chemotherapy is often poorly tolerated in elderly patients or patients with poor performance status. This trial was designed to determine whether low-dose weekly docetaxel/estramustine was efficacious with acceptable toxicity.

PATIENTS AND METHODS

Dexamethasone was administered as premedication. Subjects received docetaxel 25 mg/m2 intravenously on days 2, 9, and 16 and estramustine 140 mg orally twice daily on days 1-3, 8-10, and 15-17. Cycles were 28 days. Participants received < or = 6 cycles unless progression or intolerable toxicity occurred.

RESULTS

Fifty-eight subjects were enrolled at 31 sites in the US Oncology Network. Median age was 78 years (range, 64-92 years); performance status scores (0, 1, 2, and 3) were 36%, 38%, 24%, and 2%, respectively; 55 subjects received > or = 1 cycle of treatment; and 4 participants were nonevaluable because they completed < 2 cycles. Among the 56 treated subjects, 38 (68%) had a decreased prostate-specific antigen level (> or = 50% compared with baseline level and maintained for 4 weeks). There were 40 subjects with measurable tumor(s). Responses, assessed using Response Evaluation Criteria in Solid Tumors, were 1 complete response (2.5%), 7 partial responses (17.5%), 26 stable diseases (65%), and 6 progressive diseases (15%). At 1 year, 17% of participants were progression free; median progression-free survival was 5.3 months (range, 1-14.5 months); estimated 1-year survival was 65%. There were no grade 4 treatment-related events. Grade 3 treatment-related events included fatigue/asthenia (11%) and arrhythmia, dehydration, cerebral ischemia, thrombocytopenia, and dyspnea (4% each). There was 1 treatment-related death (acute respiratory distress syndrome).

CONCLUSION

These findings suggest that elderly men with advanced-stage prostate cancer tolerate this regimen, with significant responses and prolonged progression-free survival. These patients should not be excluded from chemotherapeutic interventions based on age alone.

Prostate adenocarcinoma manifesting as generalized lymphadenopathy

Generalized lymphadenopathy is a rare manifestation of metastatic prostate cancer. Here, we report the case of a 65-year-old patient with supraclavicular, mediastinal, hilar, and retroperitoneal lymphadenopathy and pulmonary infiltration, which suggested the diagnosis of lymphoma. There were no urinary symptoms, and the serum prostate-specific antigen (PSA) was only mildly increased with a normal free PSA. A biopsy of the supraclavicular lymph node was compatible with adenocarcinoma, whose prostatic origin was shown by immunohistochemical staining with PSA. The origin of the primary tumor was confirmed by directed prostate biopsy. We emphasize that a suspicion of prostate cancer in men with adenocarcinoma of undetermined origin is important for an adequate diagnostic and therapeutic approach.

Thalidomide/Estramustine/Paclitaxel in Metastatic Androgen-Independent Prostate Cancer

BACKGROUND

This is a phase I/II trial of thalidomide with estramustine and paclitaxel in men with androgen-independent prostate cancer (AIPC) who underwent previous chemotherapy.

PATIENTS AND METHODS

Men with progressive AIPC were treated with oral thalidomide (200 mg, 400 mg, or 600 mg daily), intravenous paclitaxel (100 mg/m2 over 3 hours on days 3 and 10), and oral estramustine (140 mg 3 times daily on days 1-5 and days 8-12) every 21 days.

RESULTS

Phase I: first cycle dose-limiting toxicity occurred in 0 of 3 patients at 200 mg thalidomide daily, 0 of 3 at 400 mg daily, and 1 of 3 at 600 mg daily (the designated maximum tolerated dose). Phase II: twenty-nine of 38 evaluable patients (76%; 95% confidence interval, 67%-87%) experienced a 50% decrease in prostate-specific antigen level. Five of 18 patients (28%) with measurable disease exhibited an objective response. Nine of 14 patients (64%) with disease refractory to previous taxane therapy had 50% decreases in prostate-specific antigen level. Grade 3/4 adverse events included neutropenia (9 of 39 [23%]), fatigue (9 of 39 [23%]), dyspnea (8 of 39 [21%]), and thromboembolic events (7 of 39 [18%]). Cumulative dose-limiting toxicity rates were minimal (13%) with thalidomide at 200 mg daily.

CONCLUSION

The profile of activity of thalidomide/paclitaxel/estramustine in taxane-refractory AIPC warrants further investigation.

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

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

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.

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.

Racial disparity in clinical course and outcome of metastatic androgen-independent prostate cancer

OBJECTIVES

To perform a review of patient and disease characteristics and response and survival outcomes of patients with metastatic androgen-independent prostate cancer. Racial differences in prostate cancer have usually been attributed to socioeconomic status, quality of care, comorbidities, and dietary factors. In a clinical trial population, some of these factors, such as access to care and performance status, are likely to be relatively uniform.

METHODS

The patients included in the review had been registered in clinical trials between 1991 and 2001 at Wayne State University.

RESULTS

Of 145 patients, 90 (62%) were white Americans and 55 (38%) were black Americans, 27% were 70 years or older, and 34% had minimal metastatic disease (axial bony involvement and/or lymph node involvement) and 66% had extensive disease (appendicular skeleton and/or visceral involvement). The chi-square test demonstrated no statistically significant difference by race in the distribution of the patient and disease characteristics. The prostate-specific antigen response rate was 41% in whites and 29% in blacks (P = 0.12). Log-rank analysis revealed race to be the only statistically significant factor predictive of the time to prostate-specific antigen progression (P = 0.02, median 4.6 months in whites and 2.3 months in blacks). No statistically significant difference by race was found in overall survival. Poor performance status, extensive disease, elevated alkaline phosphatase and lactate dehydrogenase levels, and a lack of prostate-specific antigen response were statistically significant predictors of worse overall survival.

CONCLUSIONS

In patients with androgen-independent metastatic prostate cancer studied in clinical trials, race was an independent predictor of therapeutic outcome. Additional investigation of the biologic and genetic differences underlying this clinical disparity is warranted.

Single-nucleotide polymorphisms in the 17beta-hydroxysteroid dehydrogenase genes might predict the risk of side-effects of estramustine phosphate sodium in prostate cancer patients

BACKGROUND

Estramustine phosphate sodium (EMP) frequently causes side-effects such as gastrointestinal discomfort, nausea, and edema in extremities. We analyzed single nucleotide polymorphisms (SNP) in the 17beta-hydroxysteroid dehydrogenase (HSD17B) genes, which are involved in the metabolism of EMP, to predict the risk of EMP side-effects in prostate cancer patients.

METHODS

We performed genotyping of SNP in the HSD17B genes of 44 Japanese patients with newly diagnosed prostate cancer. The association of SNP and individual EMP side-effects was evaluated.

RESULTS

Peripheral edema occurred more frequently in patients with C/C genotype of IMS-JST123219 than in those with C/G genotype (OR: 5.47, 95% CI: 1.27-23.64). Haplotype analysis showed that appetite loss was associated with the G allele of IMS-JST123219 and the T allele of IMS-JST123218 (OR: 9.13, 95% CI: 1.15-72.76).

CONCLUSIONS

These preliminary data demonstrated that analyses of SNP in the HSD17B genes might predict the occurrence of side-effects from EMP.

The current role of chemotherapy in metastatic hormone-refractory prostate cancer

Since the publication of the Southwest Oncology Group (SWOG) 99-16 and TAX 327 studies, which demonstrated a survival benefit for docetaxel-based therapy, clinicians for the first time have a therapy to offer men with metastatic prostate cancer that is not merely palliative in its effects. Phase 2 and phase 3 trials are now building on the findings of SWOG 99-16 and TAX 327 by evaluating the potential of combination taxane-based therapies, such as docetaxel plus high-dose calcitriol, docetaxel-estramustine-bevacizumab, and docetaxel-thalidomide. The optimal timing of docetaxel-based chemotherapy is still unknown, as there are no prospective clinical trial data to indicate whether earlier treatment (eg, at the time of prostate-specific antigen failure) is more or less effective than later treatment (eg, in metastatic and/or symptomatic disease).

Phase II trial of estramustine and etoposide in androgen-sensitive metastatic prostate carcinoma

BACKGROUND

Early chemohormonal therapy in metastatic prostate cancer may offer an advantage by simultaneously targeting androgen-dependent and -independent clones. Hence, a phase II trial was conducted to evaluate the efficacy and toxicity of estramustine and etoposide in hormone-sensitive metastatic prostate cancer.

PATIENT AND METHODS

Eligibility consisted of untreated metastatic prostate cancer, adequate organ function, and a performance status of 0 to 2 by Zubrod criteria. A 21-day schedule of oral estramustine (10 mg/kg/day) and etoposide (50 mg/m2/day) was administered every 28 days. Hormonal therapy was allowed at the end of the protocol therapy. Toxicity was assessed weekly, PSA levels were assessed with each cycle, and objective response was evaluated every 3 cycles.

RESULTS

Twenty-one patients were enrolled (10 white, 11 black) with a median age of 59.5 years (range, 42-79 years), a median PSA of 338 ng/mL (range, 0.9-20,000 ng/mL), and a median Gleason score of 8 points. Ten patients had bone-only metastases, 11 had measurable disease, of whom 4 had visceral metastases. A total of 128 cycles were administered (median, 6 cycles). No dose reductions were required. Nineteen patients were able to be evaluated for response. Severe toxicities included thromboembolic events and anemia in 2 patients each and fatigue in 1 patient. There were no episodes of febrile neutropenia. Response was observed in 8 of 11 patients (73%) with measurable disease. Median PSA nadir after therapy was 0.45 ng/mL, and undetectable PSA (<0.1 ng/mL) was achieved in 4 patients. Median time to PSA progression was 16.65 months. At a median follow-up of 34 months, 18 patients were alive. The 1-, 2-, and 3-year overall survival rates were 90%, 82%, and 72% respectively. Median survival has not yet been reached.

CONCLUSION

The combination of estramustine and etoposide is well tolerated, and has promising activity in newly diagnosed metastatic prostate cancer.

Novel cytotoxic and biological agents for prostate cancer: Where will the money be in 2005?

In 2004, docetaxel-based chemotherapy became the first treatment capable of extending life in androgen-independent prostate cancer. The era of therapeutic nihilism in this disease has thus been put to rest and a broad range of agents is being tested with the goal of improving on the successes of 2004. Lessons learned from other tumour types will need to be applied to prostate cancer in order to harness the bounty of available ideas. Target amplification or activating mutations and not merely the presence of a target are likely to be important to the success of targeted agents. Thus, the promise of the current crop of targeted agents is most likely to be realised when pursued in the context of well-credentialed targets and tested in highly translational clinical trials that are capable not only of assessing tumour response, but also of evaluating the status of the targeted pathway. The most promising agents in clinical development are reviewed.

Clinical trials in metastatic prostate cancer – Has there been real progress in the past decade?

Hormone refractory prostate cancer remains a challenge. While only palliative treatment strategies were available for the past several decades, many promising agents have been investigated over the past decade. Of those the taxanes appeared with significant anti-tumor activity and recently, two large randomized controlled trials demonstrated for the first time, a survival and palliative benefit with docetaxel based chemotherapy. In the current era, recurrent disease after local treatment for localized disease is diagnosed long before evidence of systemic disease. With earlier institution of hormonal treatments, patients are becoming "hormone refractory" earlier in the course of their disease with considerable long life expectancy. Hence, there is a greater need than ever for more treatment options for this expanding group of patients. A number of new systemic therapies have recently emerged, based on a deeper understanding of prostate cancer biology. Novel chemotherapeutics such as the epothilones, molecularly targeted therapies against angiogenesis, the proteosome and endothelin receptor antagonists, as well as biological agents such as anti-sense oligonucleotides are being tested as part of the armamentarium. Key to progress in the therapy of this fatal disease is the commitment and timely enrolment of prostate cancer patients in clinical trials.

Different Effect of Paclitaxel on Primary Tumor Mass, Tumor Cell Contents, and Metastases for Four Experimental Human Prostate Tumors Expressing Luciferase

Purpose: Primary tumor growth is usually assesed by measuring tumor mass or volume, under the assumption that such variables correlate with the contents of tumor cells. However, tumors are complex interacting mixtures of tumor cells and host components. The different sensitivity of such components to cytostatic agents should be taken into consideration when evaluating the effectiveness of antineoplastic agents. We evaluate the effect of the antineoplastic agent paclitaxel on primary tumors expressing luciferase and their metastases using a sensitive luminescence-based procedure to directly asses the number tumor cells, in comparison with traditionally used tumor mass measurement.

Experimental Design: Nude mice bearing human prostate tumors expressing the luciferase gene, LNCaP.Sluc, DU 145.Sluc, and PC-3.Sluc, i.m. inoculated, and PC-3M.Sluc, orthotopically inoculated, were subjected to a 10-day treatment with either 10 mg/kg/d paclitaxel or saline solution. At the end of the treatment period, primary tumors as well as metastasis target organs were harvested, weighed, and homogenized. The presence of tumor cells in the tissue homogenates was evaluated using a luminometer, following the addition of luciferin. Tumor cell equivalent is defined as the amount of light produced by a single tumor cell in culture.

Results: Paclitaxel had a different effect on the primary tumor mass and the contents of tumor cells for each tumor type. Whereas LNCaP.Sluc, PC-3.Sluc, and PC-3M.Sluc primary tumor masses were significantly reduced by the action of paclitaxel, their contents in tumor cell equivalents were not significantly affected. In contrast, paclitaxel only reduced significantly the number of tumor cell equivalents in DU 145 primary tumors. In the lymph nodes, paclitaxel reduced the number of DU 145.Sluc metastases significantly, by a factor of 103, but had no significant effect on the rest of tumor cells. However, in lungs and muscle, paclitaxel treatment reduced significantly the number of metastatic PC-3.Sluc and PC-3M.Sluc tumor cell equivalents. In the bones, no tumor cell type was significantly affected by paclitaxel.

Conclusions: Some components of tumor stroma seem to be more sensitive to antineoplastic agents than the tumor cells themselves and may also contribute to modulate the response to therapy. Our results caution against the use of a single general variable, such as tumor mass, to evaluate the effectiveness of antineoplastic agents and emphasize the effect of the tumor cell environment in their sensitivity to treatment.

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.

Phase II Randomized Trial of Weekly Paclitaxel with or Without Estramustine Phosphate in Progressive, Metastatic, Hormone-Refractory Prostate Cancer

This study was conducted to determine the similarity of response rates and safety produced by weekly paclitaxel with or without oral estramustine in patients with metastatic hormone-refractory prostate cancer. Between December 1998 and December 1999, 163 patients were randomized to receive 28-day cycles of paclitaxel 100 mg/m2 on days 2, 9, and 16 plus estramustine 280 mg orally 3 times a day on days 1-3, 8-10, and 15-17, or to receive paclitaxel 100 mg/m2 alone on days 1, 8, and 15. Objective response was defined as a > oe = 50% decrease in prostate-specific antigen (PSA) maintained for 4 weeks with stable or improved performance status. Response rates included 37 partial responses for paclitaxel/estramustine (47%) and 22 partial responses for paclitaxel (27%; P < 0.01). Median duration of response was 15.1 months for paclitaxel/estramustine and 15.5 months for paclitaxel; median survival was 16.1 months and 13.1 months, respectively (P = 0.049). Common toxicities for both treatments included neutropenia, gastrointestinal events, neuropathy, and asthenia. Thromboembolic events were more frequent in the paclitaxel/estramustine arm (no prophylactic anticoagulants). The rate of PSA decline for paclitaxel/estramustine was almost 2 times that of paclitaxel (47% vs. 27%), with acceptable toxicity. Multivariate analysis of prognostic factors affecting survival was not significant for treatment arm (P = 0.08). Although the incidence of thromboembolic events appeared to be increased in the paclitaxel/ estramustine arm, the addition of estramustine was responsible for a 20% increase in the rate of PSA decline. Neither treatment arm had significant impact on quality of life as measured by the Functional Assessment of Cancer Therapy-Prostate quality of life questionnaire. This study produced encouraging data; further studies of paclitaxel/ estramustine are recommended.

Safety and cost-effectiveness of paclitaxel administered as a 1-hour infusion versus a 3-hour infusion for various malignancies

This study challenges the current practice of administering paclitaxel for a variety of malignancies over 3 hours and documents the safety and cost-effectiveness of 1-hour administration in the outpatient setting. The authors investigated opportunities to save nursing time and costs in a cancer clinic without compromising patient safety. These savings are referred to as "opportunity-cost savings" that enable the clinic to schedule more patients during the time normally required to administer a 3-hour paclitaxel dose. Over a 2-year period, the authors were able to document significant time savings with no increase in adverse drug reactions.

Prevention and management of prostate cancer chemotherapy complications

Prevention and management of the adverse effects of prostate cancer chemotherapy depend on skilled regimen selection, dose adjustment, use of supportive care strategies, and a thorough understanding of the patient- and regimen-related factors that determine the risk for toxicity. Urologists, radiation oncologists, and primary care providers can play an important role before chemotherapy is prescribed by judicious use of treatments that impair bone marrow and other vital organ function. The current role of chemotherapy in prostate cancer is palliative. Successful palliation depends on reducing cancer-related suffering without introducing treatment-related suffering. Thus prevention and management of toxicity is central to the success of chemotherapy in advanced prostate cancer.

Multicenter Phase II study of estramustine phosphate plus weekly paclitaxel in patients with androgen-independent prostate carcinoma

BACKGROUND

The current study determined the efficacy and toxicity of weekly paclitaxel in combination with estramustine phosphate (EMP) in patients with androgen-independent prostate carcinoma (AIPC).

METHODS

Patients with progressive AIPC received 90 mg/m2 paclitaxel by 1-hour intravenous infusion weekly for 3 weeks, followed by a 1-week treatment rest. Patients received 140 mg EMP orally 3 times daily on the day before, the day of, and the day after paclitaxel administration. Patients received 1 mg warfarin daily to prevent thromboembolism.

RESULTS

Sixty-six patients with progressive AIPC received treatment at 29 centers. Forty-two percent of patients had a 50% decline in prostate-specific antigen (PSA; 95% confidence interval [CI], 30-54%). For 26 patients with bidimensionally measurable disease, the objective response rate was 15% (95% CI, 1-30%). The median time to disease progression was 6.3 months, and the median time to PSA progression was 11.4 months. The median survival period was 15.6 months. Grade 3-4 toxicities were uncommon and included thromboembolism (8%), anemia (3%), neutropenia (3%), and peripheral neuropathy (2%). There was one treatment-related death.

CONCLUSIONS

This regimen of EMP plus weekly paclitaxel was an active and well tolerated treatment for patients with AIPC.

Follow-up of conservatively managed prostate cancer: watchful waiting and primary hormonal therapy

Many men with newly diagnosed prostate cancer choose not to undergo curative treatment, including patients who cannot be helped by local curative therapies (especially those with metastatic disease) and patients with clinically localized disease who opt for expectant management or noncurative treatments such as androgen ablation. This article reviews the selection of patients for these noncurative approaches, strategies for clinical monitoring, the choices of intervention therapies upon progression, and when to start these therapies.

Pharmacotherapy of hormone refractory prostate cancer: new developments and challenges

Hormone refractory prostate cancer (HRPC) remains a challenge in the management of prostate cancer patients. With the widespread use of PSA (prostate specific antigen), recurrent disease after local treatment for localised prostate cancer is usually diagnosed long before evidence of metastatic disease. In many cases, hormonal manipulations are started at the time of biochemical relapse and therefore, patients become 'hormone refractory' earlier in the course of their disease, frequently with a good performance status, often with no evidence of metastatic disease, and they still face a considerably long life expectancy. Despite these changes, the need for more options in the treatment of HRPC is obvious. The pharmacological treatments that are in use and those that are under investigation for this group of patients will be discussed and include: cytotoxic agents including the microtubule inhibitors, alone and in combination with other conventional or experimental therapies such as calcitriol or thalidomide; treatment with epothilone analogues; endothelin receptor antagonists; palliative therapy with bisphosphonates, bone-targeted radiopharmaceuticals and other developing treatments such as vaccines, gene therapies and monoclonal antibodies.