Redefining clinically significant castration levels in patients with prostate cancer receiving continuous androgen deprivation therapy

Serum testosterone level predicts the effective time of androgen deprivation therapy in metastatic prostate cancer patients

Androgen deprivation therapy (ADT) is the standard of care for patients with metastatic prostate cancer. However, whether serum testosterone levels, using a cut-off point of 50 ng dl⁻¹, are related to the effective time of ADT in newly diagnosed prostate cancer patients remains controversial. Moreover, recent studies have shown that some patients may benefit from the addition of upfront docetaxel chemotherapy. To date, no studies have been able to distinguish patients who will benefit from the combination of ADT and docetaxel chemotherapy. This study included 206 patients who were diagnosed with metastatic prostate cancer and showed progression to castrate-resistance prostate cancer (CRPC). Serum testosterone levels were measured prospectively after ADT for 1, 3, and 6 months. The endpoint was the time to CRPC. In univariate and multivariate analyses, testosterone levels <50 ng dl⁻¹ were not associated with the effective time of ADT. Receiver operating characteristic and univariate analysis showed that testosterone levels of ≤25 ng dl⁻¹ after the first month of ADT offered the best overall sensitivity and specificity for prediction of a longer time to CRPC (adjusted hazard ratio [HR], 1.46; 95% confidence interval [95% CI], 1.08–1.96; P = 0.013). Our results show that serum testosterone level of 25 ng dl⁻¹ plays a prognostic role in prostate cancer patients receiving ADT. A testosterone value of 25 ng dl⁻¹ after the first month of ADT can distinguish patients who benefit from ADT effectiveness for only a short time. These patients may need to receive ADT and concurrent docetaxel chemotherapy.

Patient-derived xenografts as in vivo models for research in urological malignancies

Lack of appropriate models that recapitulate the complexity and heterogeneity of urological tumours precludes most of the preclinical reagents that target urological tumours from receiving regulatory approval. Patient-derived xenograft (PDX) models are characterized by direct engraftment of patient-derived tumour fragments into immunocompromised mice. PDXs can maintain the original histology, as well as the molecular and genetic characteristics of the source tumour. Thus, PDX models have various advantages over conventional cell-line-derived xenograft (CDX) and other models, which has resulted in an increase in the use of urological tumour PDXs in the analysis of tumour biology and, importantly, for drug development and treatment decisions in personalized medicine. PDX models of urological malignancies have great potential to be used for both basic and clinical research, but limitations exist and need to be overcome. In particular, several agents targeting the immune system have shown promising results in kidney and bladder cancer; however, establishing PDX models in mice with an intact immune system so that an immune response against the tumour is triggered is important to investigate these new therapeutics. Moreover, international collaboration to share PDX models is essential for research concerning fatal urological tumours.

Efficacy of Testosterone Suppression with Sustained-Release Triptorelin in Advanced Prostate Cancer

Introduction

Androgen deprivation therapy (ADT) is a mainstay of treatment against advanced prostate cancer (PC). As a treatment goal, suppression of plasma testosterone levels to <50 ng/dl has been established over decades. Evidence is growing though that suppression to even lower levels may add further clinical benefit. Therefore, we undertook a pooled retrospective analysis on the efficacy of 1-, 3-, and 6-month sustained-release (SR) formulations of the gonadotropin-releasing hormone (GnRH) agonist triptorelin to suppress serum testosterone concentrations beyond current standards.

Methods

Data of 920 male patients with PC enrolled in 9 prospective studies using testosterone serum concentrations as primary endpoint were pooled. Patients aged 42–96 years had to be eligible for ADT and to be either naïve to hormonal treatment or have undergone appropriate washout prior to enrolment. Patients were treated with triptorelin SR formulations for 2–12 months. Primary endpoints of this analysis were serum testosterone concentrations under treatment and success rates overall and per formulation, based on a testosterone target threshold of 20 ng/dl.

Results

After 1, 3, 6, 9, and 12 months of treatment, 79%, 92%, 93%, 90%, and 91% of patients reached testosterone levels <20 ng/dl, respectively. For the 1-, 3-, and 6-month formulations success rates ranged from 80–92%, from 83–93%, and from 65–97% with median (interquartile range) serum testosterone values of 2.9 (2.9–6.5), 5.0 (2.9–8.7), and 8.7 (5.8–14.1) ng/dl at study end, respectively.

Conclusion

In the large majority of patients, triptorelin SR formulations suppressed serum testosterone concentrations to even <20 ng/dl. Testosterone should be routinely monitored in PC patients on ADT although further studies on the clinical benefit of very low testosterone levels and the target concentrations are still warranted.

Electronic supplementary material

The online version of this article (doi:10.1007/s12325-016-0466-7) contains supplementary material, which is available to authorized users.

Free Testosterone During Androgen Deprivation Therapy Predicts Castration-Resistant Progression Better Than Total Testosterone

BACKGROUND

The optimal degree of testosterone suppression in patients with prostate cancer undergoing androgen deprivation therapy remains in question. Furthermore, serum free testosterone, which is the active form of testosterone, seems to correlate with intraprostatic testosterone. Here we compared free and total serum testosterone as predictors of survival free of castration resistance.

METHODS

Total testosterone (chemiluminescent assay, lower sensitivity 10 ng/dl) and free testosterone (analogue-ligand radioimmunoassay, lower sensitivity 0.05 pg/ml) were determined at 6 months of LHRH agonist treatment in a prospective cohort of 126 patients with prostate cancer. During a mean follow-up of 67 months (9-120), 75 (59.5%) events of castration-resistant progression were identified. Multivariate analysis and survival analysis according to total testosterone cutoffs of 50, 32, and 20 ng/dl, and free testosterone cutoffs of 1.7, 1.1, and 0.7 pg/ml were performed.

RESULTS

Metastatic spread was the most powerful predictor of castration resistance, HR: 2.09 (95%CI: 1.18-3.72), P = 0.012. Gleason score, baseline PSA and PSA at 6 months were also independents predictors, but not free and total testosterone. Stratified analysis was conducted on the basis of the status of metastatic diseases and free testosterone was found to be an independent predictor of survival free of castration resistance in the subgroup of patients without metastasis, HR: 2.12 (95%CI: 1.16-3.85), P = 0.014. The lowest threshold of free testosterone which showed significant differences was 1.7 pg/ml, P = 0.003.

CONCLUSIONS

Free testosterone at 6 months of LHRH agonist treatment seems to be a better surrogate than total testosterone to predict castration resistance in no metastatic prostate cancer patients. Prostate 77:114-120, 2017. © 2016 Wiley Periodicals, Inc.

Maximal testosterone suppression in the management of recurrent and metastatic prostate cancer

INTRODUCTION

Testosterone suppression, or androgen-deprivation therapy (ADT), is an established treatment for recurrent and metastatic prostate cancer (PCa). Based on the accuracy and sensitivity of early assays (c. 1960-1970), the castrate testosterone level was set at ≤1.7 nmol/l. Improved sensitivity of testosterone assays shows that both surgical and medical castration can achieve levels <0.7 nmol/l. However, the clinical implications and importance of maximum testosterone suppression remains a subject of controversy. This evidence-based review assesses prospective and retrospective clinical data, linking maximum suppression of testosterone with improved outcomes from ADT.

METHODS

PubMed and conference proceedings were searched for studies assessing the impact of low testosterone on clinical outcomes from ADT. The key search terms included combinations of prostate cancer and testosterone, predictive/prognostic, and androgen deprivation. Results were limited to studies investigating the relationship between testosterone levels and clinical outcomes.

RESULTS

Both prospective and retrospective data support a relationship between testosterone levels below the historical standard of 1.7 nmol/l and improved outcomes. Eight studies showed significant improvements in survival-related outcomes, with the majority of data supporting a testosterone level cutoff of ≤0.7 nmol/l.

CONCLUSIONS

Tracking both testosterone and prostate-specific antigen (PSA) levels has significant clinical benefits, and the serum testosterone threshold of ≤0.7 nmol/l is a practical goal. The relative levels of testosterone and PSA may indicate continued hormone responsiveness or progression toward castration-resistant prostate cancer (CRPC) and should, therefore, inform treatment strategy. Standardization of assay methods and clinical coordination to facilitate widespread access to state-of the art laboratory equipment is necessary to ensure accurate decision-making.

Luteinizing Hormone-Releasing Hormone Agonists are Superior to Subcapsular Orchiectomy in Lowering Testosterone Levels of Men with Prostate Cancer: Results from a Randomized Clinical Trial

PURPOSE

Recent evidence suggests that reaching the lowest achievable levels of testosterone with androgen deprivation therapy delays disease progression and increases overall survival in men with advanced prostate cancer. The aim of this analysis was to compare posttreatment serum testosterone levels between patients undergoing subcapsular orchiectomy and patients treated with the luteinizing hormone-releasing hormone agonist triptorelin.

MATERIALS AND METHODS

In this randomized clinical trial we included 58 consecutive hormone naïve men diagnosed with advanced prostate cancer at Herlev and Gentofte University Hospital, Herlev, Denmark from September 2013 to March 2015. Followup was 48 weeks. Participants were randomly assigned 1:1 to subcapsular orchiectomy or triptorelin 22.5 mg given as 24-week depot injections. Androgen status was measured by liquid chromatography-tandem mass spectrometry prior to treatment and after 12, 24 and 48 weeks. Between group differences in achieved hormone levels were analyzed by longitudinal Tobit regression.

RESULTS

Triptorelin injections resulted in 29% lower testosterone levels (95% CI 17.2-41.7) compared to subcapsular orchiectomy (p <0.001). A significantly higher proportion of men receiving triptorelin had testosterone levels less than 20 ng/dl at 12 and 48 weeks compared to men undergoing orchiectomy (97% vs 79% and 100% vs 87%, respectively, p <0.05). There was no detectable difference in the adrenal androgen reduction between the treatment groups.

CONCLUSIONS

The use of 24-week depot triptorelin injections results in significantly lower testosterone levels compared to subcapsular orchiectomy. To our knowledge this is the first randomized study to demonstrate a difference in treatment effect between surgical and medical castration on testosterone levels.

Androgen deprivation therapy as backbone therapy in the management of prostate cancer

Androgen deprivation therapy (ADT) is well established as a backbone therapy for metastatic prostate cancer (mPCa), and both European and American guidelines emphasize the importance of maintaining ADT after progression to metastatic castration-resistant prostate cancer (CRPC). However, the use of ADT varies widely in clinical practice despite these recommendations. Both research and development of increasingly precise assay technologies have improved our understanding of androgen production and signaling, and the recent data have suggested that a new serum testosterone cutoff value of <0.7 nmol/L should be employed. Most clinical trials to date have used the historical 1.7 nmol/L cutoff, but the <0.7 nmol/L cutoff has been associated with improved patient outcomes. Combining agents with different mechanisms of action to achieve intense androgen blockade may improve survival both before and after progression to CRPC. Data suggest that this intensive approach to androgen deprivation could delay the transition to CPRC and hence improve survival dramatically. Various combinations of backbone ADT with chemotherapy or radiotherapy are under investigation. Administration of ADT is established in patients with intermediate or high-risk localized prostate cancer (PCa) receiving radiotherapy with curative intent. This article reviews the current and potential role of ADT as backbone therapy in both hormone-sensitive PCa and CRPC with a focus on mPCa.

Role of free testosterone levels in patients with metastatic castration-resistant prostate cancer receiving second-line therapy

A range of new treatment options has recently become available for patients with advanced metastatic castration-resistant prostate cancer (mCRPC). Androgen deprivation therapy (ADT) with luteinizing hormone-releasing hormone is continued when performing chemotherapy or androgen deprivation with new second-generation therapeutic agents such as enzalutamide or abiraterone acetate. Despite the fact that free testosterone (FT) is the biologically active form, it is common practice that androgen suppression is monitored via total testosterone levels only. The aim of the present study was to evaluate the role of FT as a prognostic biomarker for cancer-specific survival (CSS) and its feasibility as an ADT monitoring biomarker in patients with mCRPC for the first time. The requirement for continued ADT in mCRPC patients is discussed within the basis of the current literature. A total of 34 patients with continuous measurements of FT levels and mCRPC status underwent therapy with docetaxel, abiraterone acetate, enzalutamide, cabozantinib, carboplatin or cabazitaxel. Data were obtained from the Departments of Urology and Urological Oncology, Hannover Medical School (Hannover, Germany) between March 2009 and April 2014. A cutoff point of 0.5 pg/ml was used to discriminate between patients according to FT levels. Statistical evaluation of CSS was performed by applying Kaplan Meier survival estimates, multivariate Cox regression analyses and log-rank tests. The median age of all 34 patients was 72 years (range, 51–86 years). The mean follow-up interval was 16.1 months (range, 0.7–55.6 months). Despite the fact that all patients were undergoing androgen deprivation, the mean serum FT levels for each patient varied; the mean FT concentration in the cohort was 0.328 pg/ml, ranging from 0.01–9.1 pg/ml. A notable difference with regard to CSS was observed for patients with regard to serum FT concentration; CSS was significantly longer for patients with a serum FT level below the cutoff level (43.6 vs. 17.3 months, respectively, P=0.0063). Upon multivariate Cox regression analysis, the mean FT concentration during treatment remained a significant prognostic factor for CSS (hazard ratio, 1.22; 95% confidence interval, 1.03–1.43; P=0.0182). In conclusion, in patients with mCRPC, the serum FT level is a strong predictor of CSS in patients under therapy with second-line anti-hormonal therapeutic medication and chemotherapy. It may be concluded that FT levels should be included into the routine control of androgen suppression while under treatment with ADT and second-generation hormonal therapy.

Measurement of serum testosterone during androgenic suppression in patients with prostate cancer: A systematic review

INTRODUCTION

Clinical practice guidelines recommend measuring serum testosterone (ST) during androgenic suppression (AS) to assess its efficacy and define castration resistance (CR). The objectives of this systematic review were to assess the level of scientific evidence that justify checking ST levels during AS, when to perform it and for what purpose.

MATERIAL AND METHODS

We performed a search in PubMed with the following mesh terms: androgen suppression, testosterone, and prostate cancer. The search was narrowed to original articles published in English.

RESULTS

We found 8 publications that analysed the clinical impact of ST concentrations during AS. In all of the series, ST was measured using chemiluminescent assays. However, only indirect methods based on liquid or gas chromatography for its extraction and subsequent quantification using mass spectrometry are recommended, especially for measuring low levels. The endpoints were specific survival and CR-free survival. Six studies were retrospective. The series were not uniform in terms of clinical stage, types of AS and ST assessment methods. In general, low ST levels (<20ng/dL or <32ng/dL) were related to longer CR-free survival. The measurements were performed every 3 or 6 months. Four studies confirmed the beneficial effect of adding bicalutamide when detecting microelevations above 50ng/dL.

CONCLUSIONS

The level of scientific evidence justifying the measurement of ST during AS is low, and the methods employed for quantifying ST levels are inadequate. However, we consider it useful to check ST levels during AS, and there appears to be an association between low ST levels and better disease outcomes. In the event of microelevations above 50ng/dL, we recommend the administration of bicalutamide.

Intramuscular depot formulations of leuprolide acetate suppress testosterone levels below a 20 ng/dL threshold: a retrospective analysis of two Phase III studies

Introduction

Androgen deprivation therapy (ADT) with gonadotropin-releasing hormone (GnRH) analogs is a standard treatment for advanced prostate cancer. GnRH analog therapy can reduce testosterone to “castrate” levels, historically defined as <50 ng/dL. With the advent of newer assays, a lower threshold of <20 ng/dL has recently been proposed. We report the results of a retrospective analysis of two Phase III trials of 4- and 6-month depot microsphere formulations of leuprolide acetate (LA), a GnRH agonist that has previously demonstrated efficacy in testosterone suppression to <50 ng/dL in patients on ADT. This analysis investigates the ability of these LA formulations to suppress to ≤20 ng/dL levels.

Methods

In two of five AbbVie/Abbott clinical trials of microsphere formulations of LA for ADT, analytic technology permitting testosterone detection as low as 3 ng/dL was used and thus was selected for this analysis. Both trials were open-label, fixed-dose studies in prostate cancer patients, naïve to ADT. Patients received either 30 mg (4-month formulation; n=49) or 45 mg (6-month formulation; n=151) depot injections of LA microspheres. Treatment duration was up to 32 weeks for the 4-month formulation and 48 weeks for the 6-month formulation. The proportion of patients achieving the 20 ng/dL threshold was determined every 4 weeks.

Results

Pooled analysis showed that 152 of 193 (79%) of patients achieved serum testosterone levels of ≤20 ng/dL at 4 weeks, and sustained the improvement at week 24 (169/189, 89%). Additionally, in the 6-month study, 127/135 (94.1%) patients were suppressed to ≤20 ng/dL at 48 weeks.

Conclusion

Both 4- and 6-month intramuscular depot formulations of LA achieved and maintained mean serum testosterone levels ≤20 ng/dL in the vast majority of patients as early as 4 weeks following treatment initiation. Additional research on the clinical relevance of this lower testosterone threshold is warranted.

Hormone naïve prostate cancer: predicting and maximizing response intervals

Hormone naïve advanced prostate cancer is subdivided into two disease states: biochemical recurrence and traditional M1 (metastatic) prostate cancer and characterized by no prior hormonal therapy or androgen deprivation therapy (ADT). In biochemical recurrence/prostate-specific antigen (PSA) recurrence, men should be risk-stratified based on their PSA doubling time, the Gleason score and the timing of the recurrence. In general, only men who are at high risk should be considered for early/immediate ADT although this is best done using shared decision with the patient. The type of ADT to be used in biochemical recurrence ranging from oral-only peripheral blockade (peripheral androgen deprivation) to complete hormonal therapy (combined androgen blockade [CAB]) remains in debate owing to lack of randomized controlled trials (RCT). However, there is good RCT support for use of intermittent hormonal therapy (IHT). There is also limited research on biomarker response (PSA and testosterone decline) to predict prognosis. On the other hand, in the setting of M1 hormone naïve prostate cancer, there are many more RCT's to inform our decisions. CAB and gonadotrophin-releasing hormone antagonists perhaps provide a slight efficacy advantage while IHT may be slightly inferior with minimal M1 disease. The PSA nadir at 7 months after starting ADT is a powerful prognostic tool for M1 patients. There is growing recognition that serum testosterone (T) control while on ADT is linked to the development of castrate-resistant prostate cancer. Especially for a M1 patient, maintaining a serum T below 20–30 ng dl⁻¹ prolongs the response to ADT. Novel oral agents (abiraterone and enzalutamide) may soon find use in hormone naïve disease and may alter the treatment landscape. Despite over 75 years of experience with ADT, many questions remain, and the field continues to evolve.

An Update on Triptorelin: Current Thinking on Androgen Deprivation Therapy for Prostate Cancer

Androgen deprivation therapy (ADT) is the mainstay palliative treatment for men with locally advanced and metastatic prostate cancer, and aims to reduce testosterone to levels obtained by surgical castration. Use of gonadotropin-releasing hormone (GnRH) agonists predominates among the ADT options. The GnRH agonist, triptorelin is a first-line hormonal therapy that has demonstrated efficacy and safety in clinical trials of patients with locally advanced non-metastatic or metastatic disease. Sustained-release 1-, 3- and 6-month formulations of triptorelin, administered intramuscularly or subcutaneously, have been developed to provide improved flexibility and convenience for the patient. Head-to-head studies of GnRH agonists are lacking in the field of prostate cancer. Despite the inevitable progression to castration-resistant prostate cancer (CRPC) in most patients receiving ADT, monitoring of testosterone levels needs to improve in routine practice and physicians should not overlook the benefits of continued ADT in their patients when introducing one of the various new treatment options for CRPC. For improved survival outcomes, there remains a need to tailor ADT treatment regimens, novel hormonal agents and chemotherapy according to the individual patient with advanced prostate cancer.

Extended release, 6-month formulations of leuprolide acetate for the treatment of advanced prostate cancer: achieving testosterone levels below 20 ng/dl

INTRODUCTION

Luteinizing hormone-releasing hormone agonists such as leuprolide acetate (LA) are the most frequently utilized treatment of advanced prostate cancer as the regimen for achieving androgen deprivation therapy (ADT). The efficacy of LA is determined by extent of testosterone (T) suppression in prostate cancer patients. Although, the historical castrate T suppression target has been defined as < 50 ng/dl, this level may not be as low as required to deliver equivalent suppression as achieved by surgical castration. Recent studies have demonstrated that a T level as low as 20 ng/dl may produce improved clinical outcomes.

AREAS COVERED

LA is available in long-acting formulations that deliver active drug over the course of 1-6 months from a single-dose administration. The technologies utilized to provide sustained drug delivery differ: one mode of administration uses microspheres, which encapsulate the drug and are injected as a suspension intramuscularly; another mode of administration uses a liquid polymer that creates a single, solid depot after injection subcutaneously. This article will review the safety and efficacy of both 6-month LA formulations, as well as their impact in prostate cancer treatment.

EXPERT OPINION

As the understanding of optimal T castrate level evolves and may be refined pending new data from contemporaneous trials, achievement and maintenance of T levels well below 50 ng/dl may be important in evaluating potential differences in ADT regimens.

Polymer-delivered subcutaneous leuprolide acetate formulations achieve and maintain castrate concentrations of testosterone in four open-label studies in patients with advanced prostate cancer

OBJECTIVE

To determine whether luteinising hormone-releasing hormone (LHRH) agonist, ATRIGEL^® polymer-delivered, subcutaneous, leuprolide acetate (ADSC-LA), formulations suppressed serum testosterone to concentrations of ≤20 ng/dL.

PATIENTS AND METHODS

Data from four open-label, fixed-dose studies were evaluated. Male patients aged 40-86 years with advanced prostatic adenocarcinoma, whom had not undergone prior androgen-deprivation therapy (ADT), were treated with a depot formulation of ADSC-LA: 7.5 mg (1-month, 120 patients), 22.5 mg (3-month, 117 patients), 30 mg (4-month, 90 patients), or 45 mg (6-month, 111 patients). Serum testosterone was sampled at screening, baseline, 2, 4, 8 h after dosing, 1, 2, 3, and 7 days, and every week until the next dose, at which time, the sampling schedule repeated until the end of study (24 weeks for 1- and 3-month formulations, 32 weeks for 4-month, and 48 weeks for the 6-month). The primary analyses were mean serum testosterone concentrations and proportion of patients who achieved concentrations of ≤20 ng/dL.

RESULTS

The mean (SE) serum testosterone concentrations at the end of study were consistently ≤20 ng/dL in each study, at 6.1 (0.4), 10.1 (0.7), 12.4 (0.8), and 12.6 (2.1) ng/dL for the 1-, 3-, 4-, and 6-month formulations, respectively. A high proportion of patients (94%, 90%, 92%, 96% for the 1-, 3-, 4-, and 6-month formulations, respectively) achieved testosterone concentrations of ≤20 ng/dL within 6 weeks, and 90-97% of patients in all studies maintained concentrations of ≤20 ng/dL from weeks 6-24.

CONCLUSIONS

Recent studies have shown improved outcomes in patients with prostate cancer who consistently attained a more rigorous level of testosterone suppression (≤20 ng/dL) with ADT than the historical standard (≤50 ng/dL). All doses of ADSC-LA rapidly achieved and maintained mean serum testosterone to the more rigorous target concentration of ≤20 ng/dL. These data suggest that ADSC-LA delivers equivalent testosterone suppression as achieved by surgical castration.

Saudi oncology society and Saudi urology association combined clinical management guidelines for prostate cancer

This is an update to the previously published Saudi guidelines for the evaluation, medical, and surgical management of patients diagnosed with prostate cancer. It is categorized according to the stage of the disease using the tumor node metastasis staging system 7(th) edition. The guidelines are presented with supporting evidence level, they are based on comprehensive literature review, several internationally recognized guidelines, and the collective expertise of the guidelines committee members (authors) who were selected by the Saudi oncology society and Saudi urological association. Considerations to the local availability of drugs, technology, and expertise have been regarded. These guidelines should serve as a roadmap for the urologists, oncologists, general physicians, support groups, and health care policy makers in the management of patients diagnosed with adenocarcinoma of the prostate to.

Expert opinion on first-line therapy in the treatment of castration-resistant prostate cancer

Treatment of metastatic castration-resistant prostate cancer (mCRPC) has been revolutionized in recent years. It is well known that androgen receptor is still active in most patients with disease progression and serum testosterone levels <50 ng/dL. Moreover, further hormonal maneuvers, either through decreasing androgen levels (abiraterone) or by targeting the androgen receptor (AR) pathway (enzalutamide), prolong survival. In addition, a new cytostatic able to overcome docetaxel resistance, cabazitaxel, and the radioisotope radium 223 have been incorporated to the armamentarium of mCRPC. mCRPC is not only a heterogeneous tumor, it changes over time developing neuroendocrine features or selection of clones resistant to hormonal maneuvers. In addition, the multiplicity of current treatments, make it necessary to design algorithms that help the specialist to choose the most appropriate treatment for a particular patient. The lack of randomized trials comparing face to face the different available options limit the scope of this review. In this article, the authors describe the prognostic factors for first line therapy in patients with mCRPC, and propose a treatment algorithm for mCRPC based on the levels of scientific evidence available and, if not available, on the consensus between medical professionals. Finally, the panel discuss how to define progressive disease in the setting of mCRPC and treatment with targeted therapies.

[Castration modalities in prostate cancer: Are they all equal?]

AIM

The aim of this literature review was to focus on the new highlights regarding oncologic and safety outcomes depending on the type of castration used.

MATERIAL

Literature search using various algorithms "prostate cancer", "castration", "agonist", "antagonist", "orchiectomy", "GnRH", "FSH", "androgen deprivation therapy" has been performed in April 2015, through the PubMed and Embase databases.

RESULTS

GnRH agonists and antagonists are both currently used in clinical practice. Nevertheless, differences regarding their pharmacologic properties have been highlighted in recent studies, specifically regarding the rapidity, sustainability and depth of the castration, but also the decrease in FSH level. Such differences may have oncological impact on the patient, regarding the disease biological control and the time to progression, and a tolerability impact, especially on the cardiovascular risks. The role of the depth and the sustainability of the castration in one hand, the FSH impact in the other hand, as well as a direct inhibition on extra-pituitary GnRH receptors by antagonist might explain these differences.

CONCLUSIONS

Recent studies suggest differences between GnRH agonists and antagonist that could impact the patient clinical outcomes. However, further high level of evidence comparative studies remains warranted.

Clinical Effect of Switching from a Luteinizing Hormone-Releasing Hormone Agonist to an Antagonist in Patients with Castration-Resistant Prostate Cancer and Serum Testosterone Level ≥ 20 ng/dl

INTRODUCTION

The efficacy of conversion from a luteinizing hormone-releasing hormone agonist to an antagonist was evaluated prospectively in patients with castration-resistant prostate cancer.

MATERIALS AND METHODS

From October 2012 to December 2014, 8 cases with a serum testosterone level ≥ 20 ng/dl during following androgen deprivation therapy were enrolled and received degarelix monthly. The primary end-pointgoal was to determine the effective prostate-specific antigen response rate. The secondary end-pointgoal was to assess the proportion of cases with a decrease in serum testosterone level to < 20 ng/ml.

RESULTS

One patient achieved a complete response, with a prostate-specific antigen level of 0.02 ng/ml at the nadirend of the study. The effective response rate was 25.0% (2/8), and the proportion of cases with prostate-specific antigen decline was 62.5% (5/8). In 5/8 cases (5/8, 62.5%), serum testosterone levels declined to < 20 ng/dl.

CONCLUSION

Switching to a luteinizing hormone-releasing hormone antagonist in patients with testosterone levels ≥ 20 ng/dl may be an option in sequential androgen deprivation therapy for some patients.

Predictors of early androgen deprivation treatment failure in prostate cancer with bone metastases

Approximately 15% of men with hormone naïve metastatic prostate cancer primarily fail to respond to androgen deprivation treatment (ADT). The reason why the response to ADT differs in this subgroup of men with prostate cancer remains unclear. The aim of this study was to describe the characteristics of these men and to thereby define predictors of early ADT failure in prostate cancer patients with bone metastases. The study was based on 915 men from the prospective randomized multicenter trial (no. 5) conducted by the Scandinavian Prostate Cancer Group comparing parenteral estrogen with total androgen blockade. Early ADT failure was defined as death from metastatic prostate cancer within 12 months after the start of ADT. Multivariate logistic regression models were applied to identify clinical predictors of early ADT failure. Ninety‐four (10.3%) men were primarily nonresponders to ADT. Independent predictors of early ADT failure were poor Eastern Cooperative Oncology Group performance status (PS), analgesic consumption, low hemoglobin, and high Soloway score (extent of disease observed on the scan), in where patients with poor PS and/or high analgesic consumption had a threefold risk of early ADT failure. Not significantly factors related to early ADT failure were age, treatment, cardiovascular comorbidity, T category, grade of malignancy, serum estrogen level, and SHBG at enrolment. We analyzed characteristics of a subgroup of patients who primarily failed to respond to ADT. Four independent clinical predictors of early ADT failure could be defined, and men exhibiting these features should be considered for an alternative treatment.

Medical Castration Using the Investigational Oral GnRH Antagonist TAK-385 (Relugolix): Phase 1 Study in Healthy Males

CONTEXT

TAK-385 is a highly selective, oral, nonpeptide GnRH antagonist being investigated as a possible prostate cancer treatment.

OBJECTIVE

The objectives were to evaluate safety, tolerability, pharmacokinetics, and pharmacodynamics of TAK-385 on LH and testosterone.

DESIGN, SETTING, AND PARTICIPANTS

This was a three-part, randomized, double-blind, placebo-controlled, phase 1 dose-escalation study in 176 healthy male UK volunteers.

INTERVENTIONS

Part 1, single doses of TAK-385 (0 [placebo], 80, 120, 180, or 360 mg). Part 2, 14-day TAK-385 (0, 20, 40, 80, or 180 mg) daily. Part 3, 28-day TAK-385 (40 [with loading dose], 60, 80, or 160 mg) or placebo daily. Parts 2 and 3 included men aged 40-75 years.

MAIN OUTCOME MEASURES

Main outcome measures included plasma concentrations of TAK-385, LH, and testosterone.

RESULTS

Oral TAK-385 was readily absorbed, and steady state was reached in ≤ 14 days. Food reduced TAK-385 systemic exposure by 47-52%. Mean serum testosterone levels declined ≤ 6 hours after TAK-385 administration. Loading doses up to 360 mg on day 1 or 360 mg on day 1 followed by 240 mg on day 2 reduced the time to achieve castrate testosterone levels from ≥ 7 to <3 days. TAK-385 doses ≥ 80 mg/d achieved sustained medical castration and trough TAK-385 concentrations >4 ng/mL. After discontinuation of TAK-385 on day 28, testosterone levels normalized in most subjects in ≤ 28 days. Common adverse events included bradycardia, headache, and hot flush (all grade ≤ 2).

CONCLUSIONS

Oral TAK-385 (40-180 mg/d) was well tolerated and effectively lowered testosterone in healthy men. Planned phase 2 doses in men with hormone-sensitive prostate cancer are 80 and 120 mg/d.

Comparison of the Efficacy of Two Brands of Triptorelin (Microrelin and Diphereline) in Reducing Prostate-Specific Antigen and Serum Testosterone in Prostate Cancer: A Double-Blinded Randomized Clinical Trial

BACKGROUND

Gonadotropin-releasing hormone (GnRH) agonists initiate androgen deprivation in treating prostate cancer (PC). Triptorelin is a synthetic GnRH and many of its market brands such as Diphereline have been introduced so far.

OBJECTIVES

We compared the efficacy of a sustained-release formulation of Triptorelin (Microrelin), domestically produced in Iran, and compared it with Diphereline in a double-blinded randomized clinical trial.

PATIENTS AND METHODS

Patients were randomly assigned to Group A (Microrelin S.R. 3.75 mg, Pooyesh Darou, Iran) and Group B (Diphereline S.R. 3.75 mg, IPSEN, France). Each patient received monthly intramuscular injections. Prostate-specific antigen (PSA) and circulatory testosterone were measured at baseline and after one, 3, and 6 months.

RESULTS

Each group contained 40 patients. In Group A, PSA was reduced from 75.78 ± 72.43 ng/mL to 1.93 ± 1.40 ng/mL after 6 months and testosterone was reduced from 3.50 ± 1.12 nmol/L to 0.81 ± 0.05 nmol/L. There was no significant difference between the efficacy of Microrelin and Diphereline. Two patients in the Microrelin Group and one patient in the Diphereline Group failed to reach medical castration (testosterone < 1.7 nmol/L), which illustrates that the power of Microrelin and Dipherelin in initiating medical castration is about 95% and 97.5%, respectively.

CONCLUSIONS

Our study showed that Microrelin is as effective as Diphereline in reducing PSA and testosterone and can be recommended to initiate medical castration in patients with PC.

Androgen deprivation therapy in castrate-resistant prostate cancer: how important is GnRH agonist backbone therapy?

BACKGROUND

A growing number of treatment options exist to treat metastatic castrate-resistant prostate cancer (mCRPC), and with these newer options, many questions about optimising treatment remain unanswered. One recommendation that may potentially be overlooked by practitioners is that androgen deprivation therapy (ADT) should be maintained when CRPC develops and when treatment with any of the newer agents is initiated.

AIM

However, to emphasise this recommendation, it is valuable to interrogate the evidence for maintaining ADT in different clinical situations.

OUTCOME

This statement, reflecting the views of the authors, provides a discussion of this evidence and the rationale behind the recommendation that ADT should be continued in CRPC.

Efficacy of triptorelin pamoate 11.25 mg administered subcutaneously for achieving medical castration levels of testosterone in patients with locally advanced or metastatic prostate cancer

OBJECTIVES

Gonadotropin-releasing hormone agonists are widely used as androgen deprivation therapy in many men with locally advanced or metastatic prostate cancer. Gonadotropin-releasing hormone agonists are delivered by intramuscular injection every 1, 3 or 6 months, but in some patients subcutaneous injection may be more appropriate. This study assessed the efficacy and safety profile of the gonadotropin-releasing hormone agonist, triptorelin pamoate, when administered by the subcutaneous route.

METHODS

In this multicentre, open-label, single-arm study, androgen deprivation therapy-naïve men with locally advanced or metastatic prostate cancer received the gonadotropin-releasing hormone agonist triptorelin pamoate 11.25 mg (3-month formulation) by the subcutaneous route twice (at baseline and 13 weeks later). The co-primary efficacy endpoints were the proportion of patients with a castration level of serum testosterone (<50 ng/dl) after 4 weeks, and of these, those still castrated after 26 weeks.

RESULTS

Of the 126 treated patients, 123 [97.6%; 95% confidence interval (CI): 93.2-99.5)] were castrated 4 weeks after the first subcutaneous injection, and 115/119 patients (96.6%; 95% CI: 91.6-99.1) castrated at 4 weeks maintained castration at 26 weeks. Median prostate-specific antigen levels were reduced by 64.2 and 96.0% at 4 and 26 weeks, respectively. The probability of maintaining a testosterone level <20 ng/dl up to 26 weeks was 90.0% (95% CI: 85.0-95.0). The most frequently occurring treatment-related adverse events were typical of gonadotropin-releasing hormone agonist treatment (hot flushes, increased weight, erectile dysfunction and hyperhidrosis).

CONCLUSIONS

This study demonstrates that triptorelin pamoate 11.25 mg administered by the subcutaneous route every 3 months is as efficacious and well tolerated as administration via the intramuscular route in men with locally advanced or metastatic prostate cancer.

Efficacy of degarelix in prostate cancer patients following failure on luteinizing hormone-releasing hormone agonist treatment: results from an open-label, multicentre, uncontrolled, phase II trial (CS27)

OBJECTIVE

To evaluate the efficacy of second-line degarelix in patients with prostate cancer (PCa) after treatment failure with a luteinizing hormone-releasing hormone (LHRH) agonist.

METHODS

This 1-year exploratory, multicentre, open-label phase II trial was performed in 2 patient cohorts (Cohort 1, n = 25; Cohort 2, n = 12) in Germany. Patients with castrate-resistant PCa after primary hormonal treatment received degarelix 240 mg, followed by 11 monthly maintenance doses of 80 mg. The primary endpoint was the proportion of patients with decreasing/stable prostate-specific antigen (PSA) (relative change ⩽+10% of baseline PSA) after 3 months.

RESULTS

At Month 3, the response rate (intention-to-treat, last observation carried forward analysis) was 16.7% [95% confidence interval (CI): 4.74-37.38] in Cohort 1 and 33.3% (95% CI: 9.92-65.11) in Cohort 2. The probability of completing 12 months without PSA progression was 8.8% (95% CI: 1.51-24.3) in Cohort 1 and 8.3% (95% CI: 0.5-31.1) in Cohort 2. Degarelix was well tolerated; the most frequently reported adverse events were local injection-site reactions.

CONCLUSIONS

In PCa patients who failed LHRH therapy, degarelix was well tolerated and achieved a limited PSA response. Phase III trials show that disease control benefits with degarelix versus agonists are more clearly demonstrated as first-line therapy.

Nadir Testosterone after Long-Term Followup Predicts Prognosis in Patients with Prostate Cancer Treated with Combined Androgen Blockade

PURPOSE

We examined the clinical significance of long-term serum testosterone monitoring to predict the prognosis of patients with prostate cancer treated with combined androgen blockade.

MATERIALS AND METHODS

We retrospectively analyzed the records of 225 patients who underwent combined androgen blockade as first line therapy for prostate cancer. The prognostic values of testosterone and other clinical factors were evaluated with respect to prostate specific antigen progression-free and overall survival.

RESULTS

Median patient age was 73.0 years, median prostate specific antigen was 42.6 ng/ml and median followup was 45.8 months. No variable associated with testosterone was predictive of progression-free survival. With regard to overall survival on univariate analysis nadir testosterone less than 16 ng/dl (p = 0.0190), less than 20 ng/dl (p = 0.0020) and less than 32 ng/dl (p = 0.0146) were significant together with other clinical factors. In contrast, nadir testosterone less than 8 and less than 12 ng/dl were not significant. Multivariate analysis showed that nadir testosterone less than 20 ng/dl was the significant prognostic factor (p = 0.0048). In addition, time to nadir testosterone was about 1 year (11.3 months). Patients were divided into rapid and slow types based on time to testosterone less than 20 ng/dl before and after 6 months, respectively. No significant difference in overall survival was observed between the 2 types. The current results suggest that the critical factor for prognosis was not a rapid decrease but whether nadir testosterone achieved a level of less than 20 ng/dl.

CONCLUSIONS

Nadir testosterone 20 ng/dl was the most significant cutoff level for overall survival in Japanese patients with prostate cancer treated with combined androgen blockade.

Nadir testosterone within first year of androgen-deprivation therapy (ADT) predicts for time to castration-resistant progression: a secondary analysis of the PR-7 trial of intermittent versus continuous ADT

PURPOSE

Three small retrospective studies have suggested that patients undergoing continuous androgen deprivation (CAD) have superior survival and time to progression if lower castrate levels of testosterone (< 0.7 nmol/L) are achieved. Evidence from prospective large studies has been lacking.

PATIENTS AND METHODS

The PR-7 study randomly assigned patients experiencing biochemical failure after radiation therapy or surgery plus radiation therapy to CAD or intermittent androgen deprivation. The relationship between testosterone levels in the first year and cause-specific survival (CSS) and time to androgen-independent progression in men in the CAD arm was evaluated using Cox regression.

RESULTS

There was a significant difference in CSS (P = .015) and time to hormone resistance (P = .02) among those who had first-year minimum nadir testosterone ≤ 0.7, > 0.7 to ≤ 1.7, and ≥ 1.7 nmol/L. Patients with first-year nadir testosterone consistently > 0.7 nmol/L had significantly higher risks of dying as a result of disease (0.7 to 1.7 nmol/L: hazard ratio [HR], 2.08; 95% CI, 1.28 to 3.38; > 1.7 nmol/L: HR, 2.93; 95% CI, 0.70 to 12.30) and developing hormone resistance (0.7 to 1.7 nmol/L: HR, 1.62; 95% CI, 1.20 to 2.18; ≥ 1.7 nmol/L: HR, 1.90; 95% CI, 0.77 to 4.70). Maximum testosterone ≥ 1.7 nmol/L predicted for a higher risk of dying as a result of disease (P = .02).

CONCLUSION

Low nadir serum testosterone (ie, < 0.7 mmol/L) within the first year of androgen-deprivation therapy correlates with improved CSS and duration of response to androgen deprivation in men being treated for biochemical failure undergoing CAD.

[Prostate cancer]

The Vall d'Hebron multidisciplinary prostate cancer (PC) team reviews recent advances in the management of this neoplasm. Screening studies with long follow-up show a reduction in mortality, whereas active surveillance is emerging as a therapeutic approach of non-aggressive cancers. New markers increase the specificity of PSA and also allow targeting suspected aggressive cancers. Multiparametric magnetic resonance (mMRI) has emerged as the most effective method in the selection of patients for biopsy and also for local tumor staging. The paradigm of random prostatic biopsy is changing through the fusion techniques that allow guiding ultrasonography-driven biopsy of suspicious areas detected in mMRI. Radical prostatectomy (RP) and radiotherapy (RT) are curative treatments of localized PC and both have experienced significant technological improvements. RP is highly effective and the incorporation of robotic surgery is reducing morbidity. Modern RT allows the possibility of high tumor dose with minimal adjacent dose reducing its toxicity. Androgen deprivation therapy with LHRH analogues remains the treatment of choice for advanced PC, but should be limited to this indication. The loss of bone mass and adverse metabolic effects increases the frequency of fractures and cardiovascular morbimortality. After castration resistance in metastatic disease, new hormone-based drugs have demonstrated efficacy even after chemotherapy resistance.

Efficacy and safety of degarelix in Korean patients with prostate cancer requiring androgen deprivation therapy: Open-label multicenter phase III study

Purpose

To assess the noninferiority, efficacy, and safety of degarelix in achieving and maintaining testosterone at castrate levels (≤0.5 ng/mL) in Korean patients (CS42) versus non-Asian patients with prostate cancer (PCa).

Methods

A Phase III, open-label, multicenter, single-arm trial was conducted in Korean patients with PCa. Degarelix was administered at a starting dose of 240 mg followed by monthly (28-day intervals) maintenance doses of 80 mg (240/80 mg dose regimen) for 7 months. The results were compared with non-Asian patients receiving degarelix 240/80 mg in the CS21 study.

Results

The estimated difference in the cumulative probabilities of testosterone ≤0.5 ng/mL from Day 28 to Day 196 between the trials was −2.3% (96.7% in CS42 vs. 99.0% in CS21). The lower limit of the 95% confidence interval was −5.5%, i.e., above the predefined noninferiority limit of −10% and thus noninferiority was established. Decreases in serum testosterone, prostate-specific antigen, and luteinizing hormone over time were similar in CS42 and CS21. There were no clinically significant differences in incidence of treatment-emergent adverse events (72% in CS42 vs. 70% in CS21) and changes in clinical chemistry and hematology parameters between the two trials. The most common adverse event was injection-site reaction.

Conclusions

Overall, degarelix was effective and well tolerated in Korean patients. Testosterone suppression was noninferior to that in non-Asian patients and safety findings were as would be expected for elderly men with PCa undergoing androgen deprivation therapy.

Testosterone Replacement Therapy in Hypogonadal Men Following Prostate Cancer Treatment: A Questionnaire-Based Retrospective Study among Urologists in Bavaria, Germany

Background: Several reports suggest testosterone replacement therapy (TRT) may be an option in selected hypogonadal patients with a history of prostate cancer (PCa) and no evidence of disease after curative treatment. Our aim was to assess TRT experience and patient management among urologists in Bavaria. Materials and Methods: Questionnaires were developed and mailed to all registered urologists in Bavaria (n = 420) regarding their experience with TRT in patients with treated PCa. Results: One hundred and ninety-three (46%) urologists returned the questionnaire and reported their experience with TRT in hypogonadal patients after curative treatment for PCa. Complete data was available for 32 men. Twenty-six patients (81%) received TRT after prostatectomy, 1 patient after external beam radiation, 3 patients after high-dose brachytherapy and 2 patients after high-intensity focused ultrasound. Of the PCa cases, 88.5% (23/26) were organ confined (pT2a-c), and 3 were pT3 tumors. All patients were pN0/cN0, and only 1 patient (pT3a) had a positive surgical margin status postoperatively. After a mean follow-up of 39.8 months, no biochemical relapse was observed. Conclusion: To date, there is no clear evidence to withhold TRT from hypogonadal men after curative PCa treatment. Our findings, although with limitations, fit in with the available data showing that TRT does not put patients at an increased risk after curative treatment of PCa.

[Castration-resistant prostate cancer (CRPC)]

In merely a short period of time the comprehension of castration-resistant prostate cancer has evolved. It is now possible to clearly outline the exact definition and variance of the disease pattern. A wealth of new effective agents can be applied to extend the patient's life span and improve the quality of life. An understanding of the pharmacodynamics and side effects of each substance is of utmost importance for the practical application. In order to use these new medicines in a differentiated manner urologists require continuous education. The evaluation of response to treatment has yet to be satisfyingly verified. Molecular markers still need to be developed and evaluated.

Correlation Between Testosterone and PSA Kinetics in Metastatic Prostate Cancer Patients Treated With Diverse Chemical Castrations

To assess total testosterone and prostatic-specific antigen (PSA) kinetics among diverse chemical castrations, advanced-stage prostate cancer patients were randomized into three groups of 20: Group 1, Leuprolide 3.75 mg; Group 2, Leuprolide 7.5 mg; and Group 3, Goserelin 3.6 mg. All groups were treated with monthly application of the respective drugs. The patients' levels of serum total testosterone and PSA were evaluated at two time periods: before the treatment and 3 months after the treatment. Spearman's rank correlation coefficient was utilized to verify the hypothesis of linear correlation between total testosterone and PSA levels. At the beginning the patients' age, stage, grade, PSA, and total testosterone were similar within the three groups, with median age 72, 70, and 70 years in Groups 1, 2, and 3, respectively. Three months after the treatment, patients who received Leuprolide 7.5 mg presented significantly lower median total testosterone levels compared with Goserelin 3.6 mg and Leuprolide 3.75 mg (9.5 ng/dL vs. 20.0 ng/dL vs. 30.0 ng/dL, respectively; p = .0072), while those who received Goserelin 3.6 mg presented significantly lower PSA levels compared with Leuprolide 7.5 mg and Leuprolide 3.75 mg (0.67 vs. 1.86 vs. 2.57, respectively; p = .0067). There was no linear correlation between total testosterone and PSA levels. Overall, regarding castration levels of total testosterone, 28.77% of patients did not obtain levels ≤50 ng/dL and 47.80% did not obtain levels ≤20 ng/dL. There was no correlation between total testosterone and PSA kinetics and no equivalence among different pharmacological castrations.

A review of continuous vs intermittent androgen deprivation therapy: redefining the gold standard in the treatment of advanced prostate cancer. Myths, facts and new data on a ″perpetual dispute″

OBJECTIVES

To review the literature and present new data of continuous androgen deprivation therapy (ADT) vs intermittent androgen deprivation (IAD) as therapies for prostate cancer in terms of survival and quality of life and clarify practical issues in the use of IAD.

MATERIALS AND METHODS

We conducted a systematic search on Medline and Embase databases using ″prostatic neoplasm″ and ″intermittent androgen deprivation″ as search terms. We reviewed meta-analyses, randomised controlled trials, reviews, clinical trials and practise guidelines written in English from 2000 and onwards until 01/04/2013. Ten randomized controlled trials were identified. Seven of them published extensive data and results randomizing 4675 patients to IAD versus CAD. Data from the other three randomized trials were limited.

RESULTS

Over the last years studies confirmed that IAD is an effective alternative approach to hormonal deprivation providing simultaneously several potential benefits in terms of quality of life and cost effectiveness. Thus, in patients with non metastatic, advanced prostate cancer IAD could be used as standard treatment, while in metastatic prostate cancer IAD role still remains ambiguous.

CONCLUSIONS

Nowadays, revaluation of the gold standard of ADT in advanced prostate cancer appears essential. Recent data established that IAD should no longer be consi¬dered as investigational, since its effectiveness has been proven, especially in patients suffering from non-metastatic advanced prostate cancer.

Efficacy and tolerability of 1- and 3-month leuprorelin acetate depot formulations (Eligard(®)/Depo-Eligard(®)) for advanced prostate cancer in daily practice: a Belgian prospective non-interventional study

INTRODUCTION

The 1-, 3- and 6- month biodegradable polymer matrix depot formulations of leuprorelin acetate (Eligard(®)/Depo-Eligard(®), Astellas Pharma Inc/BV) were shown to reduce testosterone and prostate-specific antigen levels and to be well tolerated in patients with advanced prostate cancer in several clinical trials. This study aimed at evaluating the efficacy, safety and tolerability of the 1- and 3-month leuprorelin acetate depot formulations in daily clinical practice.

MATERIAL AND METHODS

A prospective, open-label, non-interventional, phase IV study (MANTA) was conducted in 243 Belgian prostate cancer patients who had been prescribed the 1-month (7.5 mg) or 3-month (22.5 mg) leuprorelin acetate depot formulation. Patients were followed for at least 3 months.

RESULTS

Median serum prostate-specific antigen levels were reduced by 95% from 12.0 ng/ml at baseline to 0.60 ng/ml after a median follow-up time of 132 days, while median testosterone levels were reduced by 94% from 360 ng/dl to 20 ng/dl. Partial or complete treatment response was observed in 83% of patients at the final visit (according to the physician's assessment). Ninety-two patients (37.86%) experienced treatment-emergent adverse events, with injection site-related reactions, hot flushes and tumor flare being the most common ones. Overall safety and tolerability of the leuprorelin acetate depot formulation were rated as good or excellent by 90% of physicians.

CONCLUSIONS

These data are consistent with efficacy and tolerability results from clinical trials. They confirm that the 1- and 3-month leuprorelin acetate depot formulations are well tolerated and reliably lower serum prostate-specific antigen and testosterone levels in routine clinical practice.

Prognostic and predictive value of plasma testosterone levels in patients receiving first-line chemotherapy for metastatic castrate-resistant prostate cancer

BACKGROUND

Biomarkers for metastatic castration-resistant prostatic cancer (mCRPC) are an unmet medical need.

METHODS

The prognostic and predictive value for survival and response to salvage hormonal therapy (SHT) of baseline testosterone level (TL) was analysed in a cohort of 101 mCRPC patients participating in 9 non-hormonal first-line chemotherapy phase II-III trials. Inclusion criteria in all trials required a TL of <50 ng dl(-1).

RESULTS

Median age: 70 years; visceral metastases: 19.8%; median prostate-specific antigen (PSA): 50.7 ng ml(-1); median TL: 11.5 ng dl(-1). Median overall survival (OS; 24.5 months) was significantly longer if baseline TL was above (High TL; n=52) than under (Low TL; n=49) the TL median value (32.7 vs 22.4 months, respectively; P=0.0162, hazard ratio (HR)=0.6). The presence of anaemia was an unfavourable prognostic factor (median OS: 20.6 vs 28.4 months; P=0.0025, HR=1.88 (CI95%: 1.01-3.48)). Patients presenting both anaemia and low testosterone had a worse outcome compared to those with one or none of them (median OS: 17.9 vs 22.4 vs 38.1 months; P=0.0024). High vs Low TL was associated with PSA response rate (55.6% vs 21.7%) in 41 patients receiving SHT.

CONCLUSION

Testosterone level under castration range was a prognostic factor for survival mCRPC patients. The PSA response to SHT differed depending on TLs. Testosterone levels might help in treatment decision.

Is intermittent androgen-deprivation therapy beneficial for patients with advanced prostate cancer?

Use of intermittent androgen-deprivation therapy (IADT) in patients with prostate cancer has been evaluated in several studies, in an attempt to delay the development of castration resistance and reduce side-effects associated with ADT. However it is still not clear whether survival is adversely affected in patients treated with IADT. In this review, we explore the available data in an attempt to identify the most suitable candidate patients for IADT, and discuss factors that may inform appropriate patient stratification. ADT is first-line treatment for advanced/metastatic prostate cancer and is also recommended for use with definitive radiotherapy for high-risk localised prostate cancer. The changes in hormone levels induced by ADT can lead to short- and long-term side-effects which, although treatable in most cases, can significantly reduce the tolerability of ADT treatment. IADT has been investigated in several phase II and phase III studies in patients with locally advanced or metastatic prostate cancer, in an attempt to delay time to tumour progression and reduce the side-effect burden of ADT. In selected patient groups IADT is no less effective than continuous ADT, ameliorating the impact of ADT-related side-effects, and, to a degree, their impact on patient health-related quality of life (HRQL). Further comparative study is required, particularly in relation to HRQL and long-term complications associated with ADT.

A cost-utility analysis of degarelix in the treatment of advanced hormone-dependent prostate cancer in the United Kingdom

OBJECTIVE

To determine the cost-effectiveness of the treatment of advanced hormone-dependent prostate cancer with degarelix compared to luteinizing hormone-releasing hormone (LHRH) agonists in the UK using the latest available evidence and the model submitted to AWMSG.

METHODS

A cost-effectiveness model was developed from the perspective of the UK National Health Service evaluating monthly injection of degarelix against 3-monthly leuprorelin therapy plus anti-androgen flare cover for the first-line treatment of patients with advanced (locally advanced or metastatic) hormone-dependent prostate cancer. A Markov process model was constructed using the patient population characteristics and efficacy information from the CS21 Phase III clinical trial and associated extension study (CS21A). The intention-to-treat (ITT) population and a high-risk sub-group with a PSA level >20 ng/mL were modeled.

RESULTS

In the base-case analysis using the patient access scheme (PAS) price, degarelix was dominant compared to leuprorelin with cost savings of £3633 in the ITT population and £4310 in the PSA > 20 ng/mL sub-group. The chance of being cost-effective was 95% in the ITT population and 96% in the PSA > 20 ng/mL sub-group at a threshold of £20,000 per quality-adjusted life-year (QALY). In addition, degarelix remained dominant when PSA progression was assumed equal and only the benefits of preventing testosterone flare were taken into account. Treatment with degarelix also remained dominant in both populations when the list price was used. The additional investment required to treat patients with degarelix could be offset in 19 months for the ITT population and 13 months for the PSA > 20 ng/mL population. The model was most sensitive to the hazard ratio assumed for PSA progression between degarelix and leuprorelin and the quality-of-life (utility) of patients receiving palliative care.

CONCLUSION

Degarelix is likely to be cost-effective compared to leuprorelin plus anti-androgen flare cover in the first-line treatment of advanced hormone-dependent prostate cancer.

Nonmetastatic castration-resistant prostate cancer

After the introduction of prostate cancer screening with the prostate-specific antigen (PSA) test, we have witnessed a dramatic stage migration. As a result, an increasing number of patients are diagnosed at earlier stages and receive local treatments including surgery or radiation. When these local treatments fail by the definition of increasing PSA levels, patients are usually treated with androgen-deprivation therapy. A fraction of these patients will finally reach a state of castration-resistant prostate cancer (CRPC) even without radiological evidence of metastasis, which is referred to as nonmetastatic CRPC (NM-CRPC). Most men with advanced or metastatic prostate cancer initially respond to various types of androgen ablation, but a considerable portion of them eventually progress to NM-CRPC. Among patients with NM-CPRC, about one-third will develop bone metastasis within 2 years. In these patients, PSA kinetics is the most powerful indicator of progression and is usually used to trigger further imaging studies and enrollment in clinical trials. Although CRPC remains largely driven by the androgen receptor, the benefit of second-line hormonal manipulations, including first-generation antiandrogens, adrenal synthesis inhibitors, and steroids, has not been investigated in men with NM-CRPC. To date, denosumab is the only agent that has been shown to delay the onset of bone metastasis. However, overall survival did not differ. In treating NM-CRPC patients, physicians should recognize the heterogeneity of the disease and acknowledge that the recently approved second-line treatments have been studied only in advanced stages of the disease.

Current trends for the use of androgen deprivation therapy in conjunction with radiotherapy for patients with unfavorable intermediate-risk, high-risk, localized, and locally advanced prostate cancer

Androgen deprivation therapy (ADT) is now a well-established standard of care in combination with definitive radiotherapy for patients with unfavorable intermediate-risk to high-risk locally advanced prostate cancer. It is also well established that combination modality treatment with ADT and radiotherapy is superior to either of these modalities alone for the treatment of patients with high-risk locally advanced disease. Current treatment guidelines for prostate cancer in the United States are based on the estimated risk of recurrence and death. This review examines the clinical evidence underpinning the use of ADT and radiotherapy among patients with high-risk localized and locally advanced disease in the United States. This review also considers the rationale for moving from traditional luteinizing hormone-releasing hormone agonists to more recently developed gonadotrophin-releasing hormone antagonists.