Prostate-specific antigen flare phenomenon with docetaxel-based chemotherapy in patients with androgen-independent prostate cancer

OBJECTIVE

To evaluate the prostate‐specific antigen (PSA) ‘flare’ phenomenon in patients with androgen‐independent prostate cancer (AIPC) treated with docetaxel, as flare is a known effect of androgen‐deprivation therapy in hormone‐dependent prostate cancer.

PATIENTS AND METHODS

The charts of 56 patients who received docetaxel‐based chemotherapy in three different centres from August 1999 to August 2007 were reviewed retrospectively. The biochemical response was characterized according to the Bubley criteria. There was an immediate PSA response (PSA decline ≥ 50%) in 23 (41%) patients, PSA stabilization (PSA decline < 50%) in 16 (29%) and PSA progression in nine (16%). There was also a fourth response, i.e. PSA flare, defined as an increase in PSA level with no symptomatic progression, after starting docetaxel‐based chemotherapy administered every 3 weeks.

RESULTS

Eight (14%) patients with PSA flare were identified; all had osseous disease and five had additional soft‐tissue disease. The PSA flare lasted a median (range) of 21 (21–42) days and it spread over a median of 1 (1–2) cycles. The temporary PSA surge exceeded baseline values by a median (range) of 61.5 (12–404)%. There was a subsequent PSA response in six of the eight patients and PSA stabilized in the remaining two. Patients with flare received a median of 8.5 (5–12) treatment cycles, vs a median of 8 (2–12) in the immediate PSA response group (P = 0.103, Student’s t‐test). The Response Evaluation Criteria in Solid Tumors criteria evaluation showed one patient with a partial response and six with stable disease. The median survival of patients with PSA flare was 12.5 months, while that of the immediate PSA responders was 20.1 months (not statistically significant, P = 0.168, log‐rank test).

CONCLUSION

Of patients with AIPC, 14% had an initial PSA flare after starting docetaxel‐based chemotherapy. The occurrence of PSA flare had no effect on treatment duration or outcome. With lack of clinical progression, docetaxel‐based chemotherapy should be administered for at least two 3‐week cycles before further decisions are made about efficacy.     

The combination of docetaxel and the somatostatin analogue lanreotide on androgen-independent docetaxel-resistant prostate cancer: experimental data

OBJECTIVE

To evaluate the effects of the association between docetaxel and the somatostatin analogue lanreotide on the androgen‐independent prostate cancer cell line PC3, either sensitive or made resistant to docetaxel (PC3R), as new drugs and new combinations have promising clinical activity in hormone‐refractory prostate cancer.

MATERIALS AND METHODS

We examined the effect of docetaxel and lanreotide on cell proliferation, with analysis of the mitogen‐activated protein kinase pathway and expression of cell‐cycle regulatory proteins.

RESULTS

Combined treatment with docetaxel and lanreotide inhibited PC3 cell growth in vitro through an enhanced induction of cell death, compared with treatment with either agent alone; this result was particularly evident on PC3R cells. The results suggested that lanreotide could act as a P glycoprotein inhibitor in PC3R cells.

CONCLUSION

The present results provide a promising therapeutic approach for using somatostatin analogues in hormone‐refractory prostate cancer, in which lanreotide could interact with docetaxel in PC3R cells, with possible explanatory mechanisms which involve P glycoprotein‐mediated docetaxel resistance.     

Efficacy of nilutamide as secondary hormonal therapy in androgen-independent prostate cancer

OBJECTIVE: To evaluate the activity of nilutamide as secondary hormonal therapy in patients with androgen-independent prostate cancer (AIPC), as treatment options are limited for these patients and secondary hormonal therapy with antiandrogens has advantages, including low toxicity, oral administration and high patient acceptance. PATIENTS AND METHODS: We retrospectively identified 45 patients with AIPC who were treated with nilutamide as secondary hormonal therapy in two institutions. The decrease in prostate-specific antigen (PSA) levels, side-effects of treatment, and the relationship between baseline characteristics, type and duration of previous therapy and response to nilutamide were assessed. Most patients received oral nilutamide at 150 mg/day. RESULTS: Eighteen of 45 evaluable patients (40%) had a PSA level decrease of > or = 50%. Responders (PSA decline > or = 50%) had a median (range) time to progression of 4.4 (0.31-44.7) months. There were responses to nilutamide whether used as the second to fifth line of hormonal therapy. There were no differences in response to nilutamide based on clinical stage, type of local therapy, PSA level at diagnosis or initiation of nilutamide, or type of previous antiandrogen therapy. Responders were more likely to have received monotherapy with luteinizing hormone-releasing hormone analogues or orchidectomy as first-line hormonal treatment (P = 0.02). The most common reversible adverse effects were mild to moderate visual adaptation effects, reported in 20% of patients. CONCLUSIONS: Nilutamide appears to be an effective secondary hormonal therapy in patients with AIPC and is associated with a mild toxicity profile.     

High dose pulse calcitriol, docetaxel and estramustine for androgen independent prostate cancer: a phase I/II study

PURPOSE: We determined the safety and preliminary efficacy of the combination of high dose pulse calcitriol (1,25-dihydroxycholecalciferol) with a standard regimen of docetaxel plus estramustine in patients with metastatic androgen independent prostate cancer. MATERIALS AND METHODS: Patients were treated with 60 microg calcitriol orally on day 1, 280 mg estramustine orally 3 times daily on days 1 to 5 and 60 mg/m docetaxel on day 2 (70 mg/m after cycle 1) every 21 days for up to 12 cycles. Patients also received 325 mg aspirin and 1 or 2 mg warfarin orally daily. Regimen safety was assessed in the first 6 patients and a dose de-escalation scheme for calcitriol was planned if dose limiting toxicities were noted during treatment cycle 1 in greater than a third of patients. RESULTS: A total of 24 patients, including 11 who were chemotherapy na?ve and 13 who had previously been treated with docetaxel, were evaluable for toxicity and 22 for prostate specific antigen decrease data. The regimen was generally well tolerated. Treatment related grades 3 or greater toxicity seen in more than 1 patient included hypophosphatemia in 16.7% and neutropenia in 12.5%. Four patients had thromboembolic complications. Asymptomatic hypercalcemia was seen in 4 patients, including grades 2 and 1 in 1 and 3, respectively. Six of 11 evaluable, chemotherapy na?ve patients (55%) met prostate specific antigen response criteria. One of 11 patients (9%) treated with prior docetaxel met these criteria. CONCLUSIONS: High dose calcitriol may be safely added to docetaxel and estramustine administered on a 21-day schedule.     

A randomized study of docetaxel and dexamethasone with low- or high-dose estramustine for patients with advanced hormone-refractory prostate cancer

OBJECTIVE: To test the combination of docetaxel with two different doses of estramustine in patients with hormone-refractory prostate cancer (HRPC), to improve response rates and to lower side-effects, as docetaxel-based chemotherapy is an increasing option for men with advanced HRPC, and alone or combined with estramustine, docetaxel improves median survival. PATIENTS AND METHODS: In all, 72 patients with metastatic HRPC were randomly assigned to receive docetaxel (70 mg/m(2) intravenously, on day 2 every 21 days) and estramustine (3 x 280 mg/day oral starting 1 day before docetaxel, for 5 consecutive days) for arm A, or estramustine (3 x 140 mg/day oral starting 1 day before docetaxel, for 3 consecutive days) for arm B. Premedication with oral dexamethasone at a total daily dose of 16 mg, in divided doses twice a day was administered in arm A on day 1-5 and in arm B on day 1-3. Initially, six cycles were administered. Chemotherapy was restarted after a significant increase in prostate-specific antigen (PSA) level. Patients were monitored for any measurable PSA response and toxicity. RESULTS: Between the arms there was no statistically significant difference in time to progression and overall survival. However, treatment B had less treatment-related toxicity than A. Independent prognostic variables were baseline factors like PSA level, haemoglobin level, Eastern Cooperative Oncology Group performance status, and bone pain at presentation. CONCLUSIONS: In this randomized phase II study the combination of docetaxel and estramustine had substantial activity in HRPC, with a significant incidence of severe toxicity, both haematological and not. Nevertheless, treatment-related toxicity was predictable and manageable. There was no better effect with a higher dose of estramustine with docetaxel than for a lower dose. There was a slight tendency to higher toxicity for high-dose estramustine but this was not statistically significant. The present results support the assertion that estramustine is not necessary in docetaxel-based treatment regimens.     

Molecular modelling of the androgen receptor axis: rational basis for androgen receptor intervention in androgen-independent prostate cancer

Androgen depletion in combination with antiandrogenic agents is initially highly effective for treating prostate cancer, and is the recommended treatment for more advanced or higher-grade tumours. However, many tumours eventually become insensitive to androgens, even though the androgen receptor (AR) continues to be expressed. Computational chemistry combined with structural analysis of nuclear receptors and determination of binding affinities of natural and designed coregulators (coactivators and corepressors) provides the theoretical framework for the rational design of novel therapeutic agents directed at the AR. Adding alternative groups to various sites throughout the receptor can alter the conformation of the molecule and its functional binding with coactivators or corepressors. Possible molecules can be identified thoroughly and systematically using intelligent high-throughput screening and FASTrack chemistry (three-dimensional crystallography). Applying these techniques should eventually result in therapeutic agents for androgen-independent prostate cancer that can block binding of AR coactivators while simultaneously increasing binding of AR corepressors.     

Combination chemotherapy with weekly docetaxel and estramustine for hormone refractory prostate cancer in Japanese patients

Abstract:   The aim is to evaluate the efficacy and toxicity of weekly docetaxel and estramustine for Japanese men with hormone refractory prostate cancer who were treated at a single institution. Twenty eligible patients had histologically proven adenocarcinoma of the prostate with metastases that were progressing despite complete androgen blockade and antiandrogen withdrawal. All of the patients received docetaxel 30 mg/m² weekly (days 1, 8, 15, 22, 29, and 36). After a two week break, the treatment schedule was repeated. Patients were scheduled to receive daily oral estramustine 560 mg/day throughout the protocol. In the serum prostate specific antigen (PSA) response, three (15%) patients achieved a complete response, and 8 (40%) acheived a partial response. Overall survival and time to progression were 13.4 months and 6.4 months, respectively, however sixty-seven percent of the patients had to discontinue treatment because of toxicity. The high toxicity of this protocol suggests that the regimen and/or the timing should be altered for Japanese patients.     

ASCENT: the androgen-independent prostate cancer study of calcitriol enhancing taxotere

ASCENT, the Androgen-Independent Prostate Cancer (AIPC) Study of Calcitriol Enhancing Taxotere, is a double-blind, placebo-controlled randomized clinical trial designed to determine if DN-101, a high-dose oral formulation of calcitriol designed for cancer therapy, significantly increases the proportion of patients who have > 50% reduction in serum prostate-specific antigen (PSA) levels in response to docetaxel. The secondary goals of ASCENT are to evaluate the effect of DN-101 combined with docetaxel on PSA progression-free survival, tumour response rate in measurable disease, tumour progression-free survival, skeletal morbidity-free survival, clinical progression-free survival, and overall survival, and to examine the safety and tolerability of DN-101 combined with docetaxel. ASCENT builds on phase I work showing that weekly dosing allows substantial dose-escalation of calcitriol, the natural ligand for the vitamin D receptor, and on phase II work that suggested that adding weekly high-dose 'pulse' calcitriol may enhance the activity of weekly docetaxel in patients with AIPC. The preclinical rationale for calcitriol and its combination with docetaxel for prostate cancer therapy is reviewed, as are the key clinical trials that led to the development of ASCENT. The ASCENT design and its strengths and limitations are presented.     

A phase II study of high-dose calcitriol combined with mitoxantrone and prednisone for androgen-independent prostate cancer

OBJECTIVE

To evaluate the preliminary efficacy, safety, and impact on quality of life (QoL) of high‐dose calcitriol (DN‐101) combined with mitoxantrone and glucocorticoids in androgen‐independent prostate cancer (AIPC).

PATIENTS AND METHODS

Nineteen patients with metastatic AIPC and no previous chemotherapy received DN‐101 180 µg orally on day 1 and mitoxantrone 12 mg/m² intravenously on day 2 every 21 days with continuous daily prednisone 10 mg orally for a maximum of 12 cycles. A confirmed decline in prostate‐specific antigen (PSA) levels by half was the primary endpoint. QoL was evaluated using the European Organization for Research and Treatment of Cancer QLQ‐C30 questionnaire, and pain and analgesic use were evaluated.

RESULTS

Five of 19 patients (26%; 95% confidence interval, CI, 9–51) achieved a ≥50% decline in PSA level. The median (95% CI) time to PSA progression was 16 (6–26) weeks. The overall median (95% CI) survival was 16 (6–26) months; 47 (21–73)% of patients achieved an analgesic response. Toxicity was similar to that expected with mitoxantrone and prednisone alone. The QoL analysis suggested a decrease in physical functioning and increase in fatigue, insomnia, and diarrhoea.

CONCLUSIONS

DN‐101 given every 3 weeks does not add significant activity to mitoxantrone and prednisone in AIPC, as measured by the PSA decline. The high rate of analgesic response is encouraging. The addition of DN‐101 does not appear to increase the toxicity of mitoxantrone.     

Prostate-specific antigen response to deferred combined androgen blockade therapy using bicalutamide predicts survival after subsequent oestrogen and docetaxel therapies in patients with castration-resistant prostate cancer

Study Type – Prognosis (retrospective cohort analysis) Level of Evidence 2b What's known on the subject? and What does the study add? The additional use of anti‐androgen (deferred combined androgen blockade [CAB] therapy) for patients with castration‐resistant prostate cancer (CRPC) initially treated with androgen deprivation monotherapy (ADMT) can provide a clinical response, although the reported response rates vary widely. Our previous study, which reported a response rate of 66% to deferred CAB therapy, suggested that deferred CAB responders would also respond better to subsequent therapies than non‐responders because the difference in cancer‐specific survival between the deferred CAB responders and the non‐responders was much larger than the progression‐free survival rates for the responders. The present study showed that PSA response to deferred CAB therapy predicts clinical outcomes after subsequent oestrogen and docetaxel therapy. We propose that PSA response to deferred CAB be used for planning individualized treatment that includes secondary hormonal therapy and chemotherapy.

OBJECTIVE

• ? To evaluate whether there is any association between prostate‐specific antigen (PSA) response to deferred combined androgen blockade (CAB) therapy using bicalutamide in patients with castration‐resistant prostate cancer (CRPC), initially treated with castration monotherapy, and the clinical outcomes after subsequent oestrogen and docetaxel therapies.

PATIENTS AND METHODS

• ? Fifty‐six patients with advanced prostate cancer, who were refractory to both initial castration monotherapy and subsequent deferred CAB, received oestrogen therapy (estramustine phosphate 140 or 280 mg/day in 50 patients, diethylstilbestrol diphosphate 100 mg/day orally in six patients). Of the 56 patients, 33 underwent docetaxel therapy (median dose 55 mg/m², every 4–8 weeks, median 6 courses) when they became refractory to oestrogen therapy.
• ? A deferred CAB response was defined as a decrease of >50% in PSA levels after the addition of bicalutamide. The difference in cancer‐specific survival (CSS) after confirmation of resistance to initial castration monotherapy between the deferred CAB responders and the non‐responders was evaluated, and outcomes after oestrogen and docetaxel therapies were also compared between the two groups.

RESULTS

• ? A response to deferred CAB was observed in 27 (48%) of the 56 patients. There was no significant difference between the responders and the non‐responders in pretreatment clinical variables, including Gleason score, metastatic sites, PSA level at diagnosis, and PSA nadir during castration monotherapy.
• ? A deferred CAB response was a significant predictor of CSS after confirmation of resistance to initial castration monotherapy.
• ? The deferred CAB responders had significantly longer progression‐free survival (PFS) (median 3.2 months in the responders, 2.1 month in the non‐responders, P= 0.04) and CSS (median 3.0 years in the responders, 1.5 years in the non‐responders, P= 0.04) after oestrogen therapy. Likewise, PFS (median 8.2 months in the responders, 2.2 months in the non‐responders, P < 0.01) and CSS (median not reached in the responders, 1.4 years in the non‐responders, P < 0.01) after docetaxel therapy was significantly longer in the deferred CAB responders.

CONCLUSION

• ? PSA response to deferred CAB predicts clinical outcomes after subsequent oestrogen and docetaxel therapies in patients with CRPC, and provides useful information for planning individualized optimum treatment courses that include secondary hormonal therapy and chemotherapy.

     

The use of estramustine phosphate in the modern management of advanced prostate cancer

What’s known on the subject? and What does the study add? Estramustine phosphate has anti‐tumour properties and it improves patient outcomes if combined with other chemotherapy agents such as doeetaxel. The efficacy of estramustine phosphate in selected patients and its safety profile, provided used with any low‐molecular‐weight heparin support its use as a second‐line treatment in hormone‐resistant prostate cancer.

OBJECTIVES

• ? Estramustine phosphate is a nitrogen mustard derivative of estradiol‐17β‐phosphate and has anti‐tumour properties.
• ? Interest in estramustine has been renewed because of the results of clinical studies showing improved patient outcomes if estramustine is combined with other chemotherapy agents such as docetaxel.

PATIENTS AND METHODS

• ? Relevant clinical studies using chemotherapy combinations including estramustine are discussed.
• ? Efficacy and safety outcomes are summarized.

RESULTS

• ? Combination therapy with estramustine and docetaxel can increase PSA response rates, improve quality of life and increase median patient survival compared with chemotherapy regimens that do not include estramustine.
• ? Although the overall tolerability of estramustine is favourable, its use can be associated with an increased risk of thromboembolic events.

CONCLUSIONS

• ? The identification of suitable patient groups and the effective management of the risk of thromboembolism with the adjunct of low‐molecular‐weight heparins support the use of estramustine as an effective second‐line treatment strategy in hormone‐resistant prostate cancer.
• ? These promising findings warrant further investigation in a randomized clinical trial.

     

A phase I/II dose-escalation study of exisulind and docetaxel in patients with hormone-refractory prostate cancer

OBJECTIVE: To determine the safety and efficacy, in a dose-escalation study, of exisulind (an oral sulphone metabolite of sulindac thought to induce apoptosis in malignant cells by inhibiting cGMP-phosphodiesterase) combined with docetaxel in men with hormone-refractory prostate cancer (HRPC), as pre-clinical studies suggested activity against prostate cancer and synergy with cytotoxic agents. PATIENTS AND METHODS: Thirty-four patients with HRPC were treated with oral exisulind twice daily for 21-day cycles and intravenous docetaxel given for 1 h on the first day of each cycle. Three dose levels were assessed, combining exisulind 150 and 250 mg twice daily with docetaxel at 60 or 75 mg/m2. Toxicity was then evaluated using standard criteria. RESULTS: The recommended phase II dose was determined to be exisulind 250 mg and docetaxel 60 mg/m2, with escalation to 75 mg/m2 after cycle 1, as tolerated. The most common grade 3-4 toxicities among all patients were neutropenia (56%), infection (24%) and hyperglycaemia (18%). Twelve of 32 evaluable patients (38%, 95% confidence interval, CI, 23-55%) had a decline in PSA by at least half. Only four of 17 evaluable patients (95% CI, 1-47%) treated at the phase II dose level had such a decline in PSA. The median (95% CI) overall survival of all patients was 16 (12.9-19.7) months and median progression-free survival 4.7 (2.7-5.2) months. CONCLUSION: The combination of exisulind and docetaxel was tolerable in patients with HRPC. The PSA response rates do not suggest an improvement over historical data with single-agent docetaxel in this population.     

Docetaxel, with or without estramustine phosphate, as first-line chemotherapy for hormone-refractory prostate cancer: results of a multicentre, randomized phase II trial

OBJECTIVE

To report the results of a randomized phase II trial of docetaxel with and without estramustine phosphate (EP) in patients with hormone‐refractory prostate cancer (HRPC).

PATIENTS AND METHODS

Patients with progressive HRPC were randomized to receive docetaxel 70 mg/m² on day 1 (arm A), or docetaxel 70 mg/m² on day 2 plus oral EP three times daily, at a total daily dose of 840 mg, on days 1–5 (arm B). The primary objective of the trial was to evaluate the activity of the treatments in terms of the response in prostate‐specific antigen (PSA) level.

RESULTS

Forty‐five of the 49 patients centrally randomized to arm A and 44 of the 46 in arm B were evaluable for activity. The PSA level decreased by ≥50% in 40% of the patients in arm A and in 75% of those in arm B. The median time to PSA progression was 20 weeks in arm A and 30 weeks in arm B. The patients in arm B had an improvement in pain over time.

CONCLUSION

These data support the existence of a possible advantage in combining docetaxel and EP, which should be verified in a specific randomized phase III study.     

Targeting apoptosis in prostate cancer: focus on caspases and inhibitors of apoptosis proteins

Androgens are critical to the growth and differentiation of prostate epithelial cells. Removal of androgen normally results in apoptosis, but androgen-independent tumours have developed mechanisms that allow cells to survive the loss of androgen. The caspases are central mediators of cell death. An important area for research involves manipulating caspases by novel mechanisms to induce apoptosis. However, such mechanisms as diethylmaleate priming are limited by an inability to selectively target tumour cells. Inhibitors of apoptosis proteins (IAPs) are recently identified anti-apoptotic caspase regulators. Each IAP homologue has a different mechanism of action. Because more than one member of the IAP family may be overexpressed in prostate cancer, successful treatment strategies will be defined by the ability to block all of the IAP expressed. Anti-sense oligonucleotide strategies have been shown to decrease IAP expression and increase prostate cancer cell susceptibility to apoptotic induction, although not by mitochondrial-mediated pathways. Fully understanding the basic apoptotic pathway and its regulation in prostate cancer will lead to more targets for manipulation, which can be translated into novel therapies. This article focuses on the role of the caspases and IAP in developing a rational approach to using apoptosis as a therapeutic target.     

前列腺雄激素调节基因:一个新的雄激素非依赖性前列腺癌治疗的潜在靶点(英文)

目的:初步研究前列腺雄激素调节基因(PAR)与雄激素—雄激素受体信号转导通路的关系及其在前列腺癌细胞恶性转化过程中的作用,探讨通过抑制 PAR 基因治疗雄激素非依赖性前列腺癌的可能性。方法:用 RT-PCR 检测 LNCaP、PC3细胞中 PAR 基因 mRNA 表达水平的差异。分别用 RT-PCR 检测双氢睾酮对LNCaP、PC3及稳定转染了 pcDNA3-AR 的 PC3细胞株 PC3-AR 的 PAR 基因 mRNA 表达的调节作用,并观察这一调节作用是否可被雄激素受体拮抗剂氟他胺阻断。进一步用 RNA 干扰技术下调 PC3细胞 PAR 的表达,用细胞计数、软琼脂克隆形成实验、流式细胞术研究 PAR 基囚表达下调对 PC3细胞生长的抑制作用。结果:PC3细胞 PAR 基因 mRNA 的表达是 LNCaP 细胞的3倍;双氢睾酮可调节 LNCaP 和 PC3-AR 细胞株PAR 基因 mRNA 表达水平,此种对 PAR 表达的调节作用可被氟他胺阻断:双氢睾酮对 PC3细胞 PAR 基因mRNA 表达无明显影响。RNA 干扰可抑制 PC3细胞 PAR 基因表达,使细胞增殖受抑制,细胞周期阻滞于G_2-M 期,凋亡增加。结论:PAR 可能是雄激素—雄激素受体信号转导通路下游的与雄激素非依赖性前列腺癌恶性表型密切相关的癌基因,有望成为其基冈和药物治疗的靶点。     

Evaluation of docetaxel plus estramustine in the treatment of patients with hormone-refractory prostate cancer

Objectives:   To investigate the feasibility and efficacy of docetaxel-based chemotherapy in patients with hormone-refractory prostate cancer (HRPC).
Methods:   Forty-six consecutive HRPC patients treated between January 2003 and March 2008 were included in this analysis. Docetaxel was given at a dose of 35 mg/m² twice every 3 weeks and oral estramustine concurrently for three consecutive days during weeks 1 and 2 of each cycle. During each treatment week, the dose of estramustine was 1260 mg on the first day, 980 mg on the second day and 840 mg on the third day. Patients were premedicated with 4 mg twice a day of oral dexamethasone for three consecutive days. Treatment was continued until evidence of disease progression or unacceptable toxicity. Prostate-specific antigen (PSA) levels were evaluated at least once every 4 weeks.
Results:   Patients received a median of three cycles of chemotherapy. Of the evaluable 46 patients, 25 (54%) had a ≥50% PSA decline and 12 (26%) had a ≥75% PSA decline. Median time to PSA progression and overall survival time were 10.1 and 27.0 months, respectively. Median follow-up was 15.0 months. Major severe toxicities were grade 3 or 4 leukopenia in five (11%) patients. Mild toxicities included grade 1 or 2 nausea in eight (17%) patients. Two patients could not continue the treatment because of interstitial pneumonitis and a gastric hemorrhage, respectively.
Conclusions:   Docetaxel plus estramustine chemotherapy represents an active and well tolerated treatment for Japanese HRPC patients.     

Phase II study of docetaxel re‐treatment in docetaxel‐pretreated castration‐resistant prostate cancer

Study Type – Therapy (cohort)
Level of Evidence 2b What’s known on the subject? and What does the study add? We show that (i) docetaxel re‐treatment, after a treatment‐free interval, preserves activity; (ii) the treatment is especially well tolerated in patients who were effectively pretreated with docetaxel; and (iii) it could be speculated that combining docetaxel with other agents in this setting might be safe and result in greater activity.

OBJECTIVE

To determine the activity and tolerability of docetaxel re‐treatment after first‐line therapy with docetaxel in castration‐resistant prostate cancer (CRPC).

PATIENTS AND METHODS

Between November 2005 and January 2009, 45 patients initially responding to docetaxel and then experiencing disease progression after a period of biochemical remission of at least 5 months were enrolled in a prospective multicenter study and re‐treated with docetaxel. The primary endpoint was the biochemical response (biochemical partial response defined as >50% prostate‐specific antigen [PSA] decline); secondary endpoints were objective response, toxicity, progression‐free survival (PFS) and overall survival (OS).

RESULTS

Partial PSA responses were observed in 11 patients (24.5%), 4 (25%) of whom also had an objective response. The treatment was well tolerated, with grade 1–2 neutropenia, thrombocytopenia, vomiting and peripheral neuropathy noted in 18 (40%), 11 (24.5%), 8 (17.8%), and 6 (13.3%) patients, respectively. The most common grade 3 toxicity was neutropenia, which was observed in 8 patients (17.8%). Median PFS was 5 months and median OS was 13 months.

CONCLUSIONS

Docetaxel re‐treatment preserves anti‐tumour activity and is well tolerated in a selected population of pretreated patients with CRPC. Further randomized trials are needed to confirm our preliminary results.