Randomised phase II/III study of docetaxel with or without risedronate in patients with metastatic Castration Resistant Prostate Cancer (CRPC), the Netherlands Prostate Study (NePro)

Zhoushi Qi Ling decoction inhibits the progression of castration-resistant prostate cancer in vivo by regulating macrophage infiltration via IL6-STAT3 signaling

Background and aim

Prostate cancer is a leading malignant tumor in men, associated with a high rate of mortality. Androgen deprivation therapy is commonly used to treat prostate cancer, which contributes to the progression of castration-resistant prostate cancer (CRPC). The current therapy has a low survival rate in patients with CRPC. Our study aims to develop a novel effective approach for CRPC treatment and improve survival benefits.

Experimental procedure

CRPC cell line PC-3-Luc expressing luciferase and the CRPC cell line PC-3-IL6-Luc stably overexpressing IL-6 were used to establish the xenograft tumor mouse model. The tumor was monitored weekly using Bioluminescence imaging. Infiltrated macrophages were quantified by fluorescence-activated cell sorting using flow cytometry. IL6 mRNA level was determined using quantitative real-time PCR. The protein levels of total STAT3 and phosphorylated STAT3 were determined using Western blot.

Results and conclusion

Zhoushi Qi Ling decoction (ZQD) treatment significantly reduced PC3 the xenograft tumor progression and the number of infiltrated macrophages when compared with saline treatment. IL6 mRNA level was remarkedly suppressed by ZQD treatment. Notably, the protein level of phosphorylated STAT3 was significantly decreased in PC3 the xenograft tumor treated with ZQD compared to saline treatment. Our findings demonstrated that ZQD treatment significantly reduced the progression of prostate cancer, evidenced by the reduced population of infiltrated macrophages and the inhibition of the IL6/STAT3 pathway.

Prostate cancer bone metastases biology and clinical management (Review)

Prostate cancer (PCa) is one of the most prominent causes of cancer-related mortality in the male population. A highly impactful prognostic factor for patients diagnosed with PCa is the presence or absence of bone metastases. The formation of secondary tumours at the bone is the most commonly observed site for the establishment of PCa metastases and is associated with reduced survival of patients in addition to a cohort of life-debilitating symptoms, including mobility issues and chronic pain. Despite the prevalence of this disease presentation and the high medical relevance of bone metastases, the mechanisms underlying the formation of metastases to the bone and the understanding of what drives the osteotropism exhibited by prostate tumours remain to be fully elucidated. This lack of in-depth understanding manifests in limited effective treatment options for patients with advanced metastatic PCa and culminates in the low rate of survival observed for this sub-set of patients. The present review aims to summarise the most recent promising advances in the understanding of how and why prostate tumours metastasise to the bone, with the ultimate aim of highlighting novel treatment and prognostic targets, which may provide the opportunity to improve the diagnosis and treatment of patients with PCa with bone metastases.

Management of cancer pain due to bone metastasis

Bone metastases frequently occur in patients with cancer. Skeletal-related events (SREs), including pain, impaired mobility, hypercalcemia, pathological fracture, spinal cord and nerve root compression, and bone marrow infiltration, can decrease the quality of life of the patients and increase the risk of morbidity. The mechanism of pain due to bone metastasis is complicated and involves various interactions among tumor cells, bone cells, activated inflammatory cells, and bone-innervating neurons. Cancer pain due to bone metastasis can be crippling and a chronic state that causes sarcopenia. For pain management, it is important to diagnose whether the pain is based on background pain or breakthrough pain due to bone metastasis. In addition, the management goal of cancer pain due to bone metastasis is not only to achieve pain relief but also to prevent pain progression and SREs. Pain mechanisms should be applied to achieve optimal management. This review aims to discuss the mechanisms of cancer pain due to bone metastasis and review the recommended drug therapies.

The presenting dental status of solid tumours with bone metastases requiring bone-targeting agents - part 3: prostate cancer

Introduction Metastatic prostate cancer (MPC) patients due to receive bone-targeting agents (BTAs) are expected to undertake a dental assessment before commencing. The aim of this study was to determine the dental status of this tumour group and understand the challenges the dental practitioner faces in attempting to achieve 'dental fitness'.Materials and methods Data were retrospectively collected from a dedicated pre-BTA dental assessment clinic and analysed for MPC. Statistical analysis and observational data were used to compare patient and tumour demographics.Results A total of 111 patients were included in this cohort, with the majority of patients presenting with only bone metastases (BM) and no additional metastatic sites. On average, MPC patients presented with 19.3 teeth and were below the threshold for functional dentition. The 75-84-year-old age group had the worst horizontal bone loss score and subsequently lose six teeth over a decade (p = 0.001). In addition, all MPC tumour sub-categories showed favourable survival rates.Conclusion MPC patients have a high dental burden on presentation, likely associated with their age. Favourable survival prospects and the cumulation of BTAs and dental disease would suggest a heightened risk of medication-related osteonecrosis of the jaw in this group compared to many other tumour sites.

Bisphosphonates or RANK-ligand-inhibitors for men with prostate cancer and bone metastases: a network meta-analysis

BACKGROUND

Different bone-modifying agents like bisphosphonates and receptor activator of nuclear factor-kappa B ligand (RANKL)-inhibitors are used as supportive treatment in men with prostate cancer and bone metastases to prevent skeletal-related events (SREs). SREs such as pathologic fractures, spinal cord compression, surgery and radiotherapy to the bone, and hypercalcemia lead to morbidity, a poor performance status, and impaired quality of life. Efficacy and acceptability of the bone-targeted therapy is therefore of high relevance. Until now recommendations in guidelines on which bone-modifying agents should be used are rare and inconsistent.

OBJECTIVES

To assess the effects of bisphosphonates and RANKL-inhibitors as supportive treatment for prostate cancer patients with bone metastases and to generate a clinically meaningful treatment ranking according to their safety and efficacy using network meta-analysis.

SEARCH METHODS

We identified studies by electronically searching the bibliographic databases Cochrane Controlled Register of Trials (CENTRAL), MEDLINE, and Embase until 23 March 2020. We searched the Cochrane Library and various trial registries and screened abstracts of conference proceedings and reference lists of identified trials.

SELECTION CRITERIA

We included randomized controlled trials comparing different bisphosphonates and RANKL-inihibitors with each other or against no further treatment or placebo for men with prostate cancer and bone metastases. We included men with castration-restrictive and castration-sensitive prostate cancer and conducted subgroup analyses according to this criteria.

DATA COLLECTION AND ANALYSIS

Two review authors independently extracted data and assessed the quality of trials. We defined proportion of participants with pain response and the adverse events renal impairment and osteonecrosis of the jaw (ONJ) as the primary outcomes. Secondary outcomes were SREs in total and each separately (see above), mortality, quality of life, and further adverse events such as grade 3 to 4 adverse events, hypocalcemia, fatigue, diarrhea, and nausea. We conducted network meta-analysis and generated treatment rankings for all outcomes, except quality of life due to insufficient reporting on this outcome. We compiled ranking plots to compare single outcomes of efficacy against outcomes of acceptability of the bone-modifying agents. We assessed the certainty of the evidence for the main outcomes using the GRADE approach.

MAIN RESULTS

Twenty-five trials fulfilled our inclusion criteria. Twenty-one trials could be considered in the quantitative analysis, of which six bisphosphonates (zoledronic acid, risedronate, pamidronate, alendronate, etidronate, or clodronate) were compared with each other, the RANKL-inhibitor denosumab, or no treatment/placebo. By conducting network meta-analysis we were able to compare all of these reported agents directly and/or indirectly within the network for each outcome. In the abstract only the comparisons of zoledronic acid and denosumab against the main comparator (no treatment/placebo) are described for outcomes that were predefined as most relevant and that also appear in the 'Summary of findings' table. Other results, as well as results of subgroup analyses regarding castration status of participants, are displayed in the Results section of the full text. Treatment with zoledronic acid probably neither reduces nor increases the proportion of participants with pain response when compared to no treatment/placebo (risk ratio (RR) 1.46, 95% confidence interval (CI) 0.93 to 2.32; per 1000 participants 121 more (19 less to 349 more); moderate-certainty evidence; network based on 4 trials including 1013 participants). For this outcome none of the trials reported results for the comparison with denosumab. The adverse event renal impairment probably occurs more often when treated with zoledronic acid compared to treatment/placebo (RR 1.63, 95% CI 1.08 to 2.45; per 1000 participants 78 more (10 more to 180 more); moderate-certainty evidence; network based on 6 trials including 1769 participants). Results for denosumab could not be included for this outcome, since zero events cannot be considered in the network meta-analysis, therefore it does not appear in the ranking. Treatment with denosumab results in increased occurrence of the adverse event ONJ (RR 3.45, 95% CI 1.06 to 11.24; per 1000 participants 30 more (1 more to 125 more); high-certainty evidence; 4 trials, 3006 participants) compared to no treatment/placebo. When comparing zoledronic acid to no treatment/placebo, the confidence intervals include the possibility of benefit or harm, therefore treatment with zoledronic acid probably neither reduces nor increases ONJ (RR 1.88, 95% CI 0.73 to 4.87; per 1000 participants 11 more (3 less to 47 more); moderate-certainty evidence; network based on 4 trials including 3006 participants). Compared to no treatment/placebo, treatment with zoledronic acid (RR 0.84, 95% CI 0.72 to 0.97) and denosumab (RR 0.72, 95% CI 0.54 to 0.96) may result in a reduction of the total number of SREs (per 1000 participants 75 fewer (131 fewer to 14 fewer) and 131 fewer (215 fewer to 19 fewer); both low-certainty evidence; 12 trials, 5240 participants). Treatment with zoledronic acid and denosumab likely neither reduces nor increases mortality when compared to no treatment/placebo (zoledronic acid RR 0.90, 95% CI 0.80 to 1.01; per 1000 participants 48 fewer (97 fewer to 5 more); denosumab RR 0.93, 95% CI 0.77 to 1.11; per 1000 participants 34 fewer (111 fewer to 54 more); both moderate-certainty evidence; 13 trials, 5494 participants). Due to insufficient reporting, no network meta-analysis was possible for the outcome quality of life. One study with 1904 participants comparing zoledronic acid and denosumab showed that more zoledronic acid-treated participants than denosumab-treated participants experienced a greater than or equal to five-point decrease in Functional Assessment of Cancer Therapy-General total scores over a range of 18 months (average relative difference = 6.8%, range -9.4% to 14.6%) or worsening of cancer-related quality of life.

AUTHORS' CONCLUSIONS

When considering bone-modifying agents as supportive treatment, one has to balance between efficacy and acceptability. Results suggest that Zoledronic acid likely increases both the proportion of participants with pain response, and the proportion of participants experiencing adverse events However, more trials with head-to-head comparisons including all potential agents are needed to draw the whole picture and proof the results of this analysis.

Quality-of-Life Assessment and Reporting in Prostate Cancer: Systematic Review of Phase 3 Trials Testing Anticancer Drugs Published Between 2012 and 2018

Quality of life (QoL) is not included among the end points in many studies, and QoL results are underreported in many phase 3 oncology trials. We performed a systematic review to describe QoL prevalence and heterogeneity in QoL reporting in recently published prostate cancer phase 3 trials. A PubMed search was performed to identify primary publications of randomized phase 3 trials testing anticancer drugs in prostate cancer, issued between 2012 and 2018. We analyzed QoL inclusion among end points, presence of QoL results, and methodology of QoL analysis. Seventy-two publications were identified (15 early-stage, 20 advanced hormone-sensitive, and 37 castration-resistant prostate cancer [CRPC]). QoL was not listed among study end points in 23 studies (31.9%) (40.0% early stage, 40.0% advanced hormone sensitive, and 24.3% CRPC). QoL results were absent in 15 (30.6%) of 49 primary publications of trials that included QoL among end points. Overall, as a result of absent end point or unpublished results, QoL data were lacking in 38 (52.8%) primary publications (53.3% early stage, 55.0% in advanced hormone sensitive, and 51.4% in CRPC). The most commonly used QoL tools were Functional Assessment of Cancer Therapy-Prostate (FACT-P) (21, 53.8%) and European Organization for Research and Treatment of Cancer Quality of Life Questionnaire-Core 30 (EORTC QLQ-C30) (14, 35.9%); most common methods of analysis were mean changes or mean scores (28, 71.8%), time to deterioration (14, 35.9%), and proportion of patients with response (10, 25.6%). In conclusion, QoL data are lacking in a not negligible proportion of recently published phase 3 trials in prostate cancer, although the presence of QoL results is better in positive trials, especially in CRPC. The methodology of QoL analysis is heterogeneous for type of instruments, analysis, and presentation of results.

Effect of bisphosphonates on overall survival in subgroups of patients with prostate cancer

Adjuvant therapy with bisphosphonates in prostate cancer is effective in improving bone mineral density and thus reducing fractures and skeletal-related events. We analyzed the effect of bisphosphonates on overall survival (OS) in subgroups of patients with prostate cancer. A systematic literature search was conducted of the PubMed database and the bibliographies of related studies. The long-term OS rates were extracted from every eligible trial. The hazard ratio (HR) was pooled with the fixed effects model, and preplanned subgroup analyses were performed. The search yielded 112 articles, of which 10 articles with 13 patient subgroups met the eligibility criteria. The meta-analysis of all 13 subgroups showed that adjuvant bisphosphonate therapy did not significantly improve OS versus the control group (HR = 0.961, 95% CI 0.899-1.026, p = 0.233) with low heterogeneity (I² = 13.47%, degrees of freedom = 12, p = 0.336). There was no significant improvement in OS with the addition of bisphosphonates in the major subgroup analyses (metastatic (M1) versus non-metastatic, clodronate versus zoledronic acid, castration-sensitive prostate cancer (CSPC) versus castration-refractory prostate cancer). When the subgroups were further divided, adjuvant bisphosphonate therapy significantly improved OS in patients with CSPC + M1 (HR = 0.874, 95% CI 0.778-0.982, p = 0.023; I² = 0.0%, degrees of freedom = 3, p = 0.579). Our study demonstrated that bisphosphonates do not significantly improve long-term OS in patients with prostate cancer. However, adjuvant bisphosphonate therapy significantly improves OS in the subgroup of patients with CSPC + M1.

The efficacy and safety comparison of docetaxel, cabazitaxel, estramustine, and mitoxantrone for castration-resistant prostate cancer: A network meta-analysis

AIMS

The aim of this study was to compare the efficacy and safety of docetaxel, cabazitaxel, docetaxel + estramustine, mitoxantrone in the management of castration-resistant prostate cancer (CRPC).

METHODS

Electronic databases including PubMed, Cochrance Library and Embase were searched for studies published from when the databases were established to January 1st, 2018. Randomized controlled trials (RCTs) that compared docetaxel + prednisone (DP), cabazitaxel + prednisone (CP), docetaxel + estramustine + prednisone (DEP), and mitoxantrone + cabazitaxel + prednisone (MP) for CRPC treatment were identified. The network meta-analysis was conducted with software R 3.3.2. We analyzed the main outcomes, including the overall survival (OS), progression-free survival (PFS), prostate-specific antigen (PSA) response, tumor response and severe adverse events (AEs). Ranking of the chemotherapeutic agents was based on probabilities of interventions for each of the outcomes that were performed. The consistency of direct and indirect evidence was assessed by node splitting.

RESULTS

10 RCTs, with 3590 patients, were analyzed. The network meta-analysis results revealed that CP significantly increased OS, PFS, PSA response, tumor response, and severe AEs compared to MP. DP showed similar results with CP except for tumor response, where it showed slight inferiority in effectiveness. DEP was associated with clearly improved outcomes in PFS, PSA response and tumor response compared to those of MP, but this was not the case for OS benefit and severe AEs. No significant difference was detected in DP, CP and DEP except for the outcomes of severe AEs. MP was less effective in survival and clinical benefit, but much safer in safety outcomes than other chemotherapy agents. The probabilities of rank plots showed that CP ranked first in OS and tumor response; DEP ranked first in PFS time and PSA response; MP was the best treatment mode for safety.

CONCLUSIONS

DP and CP survival benefit (OS, PFS) and clinical benefit (PSA response and tumor response) were comparable, as well as their associated AEs. DEP was associated with less survival benefit, similar clinical improvement and more AEs than DP or CP. MP had the lowest survival and clinical benefit but excellent safety than other agents. Based on evidences of current results, we recommended CP as the most suitable chemotherapy agent for CRPC patients, followed by DP, MP as third, and DEP as the last choice. However, considering limitations of our network meta-analysis, additional high-quality studies are needed for further evaluation.

Bisphosphonates for advanced prostate cancer

BACKGROUND

The prevalence and incidence of pain and skeletal complications of metastatic bone disease such as pathologic fractures, spinal cord compression and hypercalcemia is high and an important contributor to morbidity, poor performance status and decreased quality of life. Moreover, pathologic fractures are associated with increased risk of death in people with disseminated malignancies. Therefore, prevention of pain and fractures are important goals in men with prostate cancer at risk for skeletal complications.

OBJECTIVES

To assess the effects of bisphosphonates in men with bone metastases from prostate cancer.

SEARCH METHODS

We identified studies by electronic search of bibliographic databases including the Cochrane Controlled Trials Register and MEDLINE on 13 July 2017 and trial registries. We handsearched the Proceedings of American Society of Clinical Oncology (to July 2017) and reference lists of all eligible trials identified. This is an update of a review last published in 2006.

SELECTION CRITERIA

We included randomized controlled studies comparing the effectiveness of bisphosphonates in men with bone metastases from prostate cancer.

DATA COLLECTION AND ANALYSIS

Two review authors independently extracted data and assessed the quality of trials. We defined the proportion of participants with pain response as the primary end point; secondary outcomes were skeletal-related events, mortality, quality of life, adverse events, analgesic consumption and disease progression. We assessed the quality of the evidence for the main outcomes using the GRADE approach.

MAIN RESULTS

We included 18 trials reporting on 4843 participants comparing the effect of bisphosphonate administration to control regimens.

PRIMARY OUTCOME

there was no clear difference in the proportion of participants with pain response (RR 1.15, 95% CI 0.93 to 1.43; P = 0.20; I² = 0%; 3 trials; 876 participants; low quality evidence). In absolute terms, bisphosphonates resulted in a pain response in 40 more participants per 1000 (19 fewer to 114 more).

SECONDARY OUTCOMES

bisphosphonates probably reduced the incidence of skeletal-related events in participants with prostate cancer metastatic to bone (RR 0.87, 95% CI 0.81 to 0.94; P = 0.27; I² = 19%; 9 trials; 3153 participants; moderate quality evidence). In absolute terms, bisphosphonates resulted in 58 fewer SREs per 1000 (85 fewer to 27 fewer).We found no clinically relevant differences in mortality (RR 0.97, 95% CI 0.91 to 1.04; P = 0.43; I² = 1%; 9 trials; 2450 participants; moderate quality evidence). In absolute terms, bisphosphonates resulted in 16 fewer deaths per 1000 (47 fewer to 21 more).Outcome definition of quality of life and the measurement tools varied greatly across trials and we were unable to extract any quantitative data for meta-analysis.Bisphosphonates probably increased the number of participants affected by nausea (RR 1.19, 95% CI 1.00 to 1.41; P = 0.05; I² = 0%; 9 trials; 3008 participants; moderate quality evidence). In absolute terms, bisphosphonates resulted in seven more cases of nausea per 1000 (0 fewer to 14 more). Bisphosphonates probably increased the number of renal adverse events (RR 1.65, 95% CI 1.11 to 2.46; P = 0.01; I² = 0%; 7 trials; 1794 participants; moderate quality evidence). In absolute terms, bisphosphonates resulted in 22 more renal adverse events per 1000 (4 more to 50 more). We found no clear difference in the number of participants with osteonecrosis of the jaw between groups (RR 1.92, 95% CI 0.75 to 4.90; P = 0.17; I² = 0%; 5 trials; 1626 participants; very low quality evidence). In absolute terms, bisphosphonates resulted in seven more cases with osteonecrosis of the jaw per 1000 (2 fewer to 29 more). We observed no clinically relevant difference in the proportion of participants with decreased analgesic consumption (RR 1.19, 95% CI 0.87 to 1.63; P = 0.28; I² = 37%; 4 trials; 416 participants). Statistical analysis revealed that bisphosphonates probably reduced the number of participants with disease progression (RR 0.94, 95% CI 0.90 to 0.98; P = 0.006; I² = 0%; 7 trials; 2115 participants; moderate quality evidence). In absolute terms, bisphosphonates resulted in 36 fewer cases of disease progression per 1000 (71 fewer to 7 fewer).Findings of our predefined subgroup and sensitivity analyses were no different from those of the primary analyses.

AUTHORS' CONCLUSIONS

Based on low quality evidence, there may be no clinically relevant difference in the proportion of men with pain response between bisphosphonates and control regimens in men with bone metastases from prostate cancer. Bisphosphonates probably decrease the number of skeletal-related events and disease progression. These benefits need to be weighed against the increased risk of renal impairment and nausea in men receiving bisphosphonates. Future studies should explicitly evaluate patient important outcomes such as quality of life and pain by using standardized and comparable assessment tools.

A randomised, phase II study of repeated rhenium-188-HEDP combined with docetaxel and prednisone versus docetaxel and prednisone alone in castration-resistant prostate cancer (CRPC) metastatic to bone; the Taxium II trial

BACKGROUND

Rhenium-188-HEDP is a beta-emitting radiopharmaceutical used for palliation of metastatic bone pain. We investigated whether the addition of rhenium-188-HEDP to docetaxel/prednisone improved efficacy of chemotherapy in patients with CRPC.

METHODS

Patients with progressive CRPC and osteoblastic bone metastases were randomised for first-line docetaxel 75 mg/m² 3-weekly plus prednisone with or without 2 injections of rhenium-188-HEDP after the third (40 MBq/kg) and after the sixth (20 MBq/kg) cycle of docetaxel. Primary endpoint was progression-free survival (PFS), defined as either PSA, radiographic or clinical progression. Patients were stratified by extent of bone metastases and hospital.

RESULTS

Forty-two patients were randomised for standard treatment and 46 patients for combination therapy. Median number of cycles of docetaxel was 9 in the control group and 8 in the experimental group. Median follow-up was 18.4 months. Two patients from the experimental group did not start treatment after randomisation. In the intention to treat analysis no differences in PFS, survival and PSA became apparent between the two groups. In an exploratory per-protocol analysis median overall survival was significantly longer in the experimental group (33.8 months (95%CI 31.75-35.85)) than in the control group (21.0 months (95%CI 13.61-28.39); p 0.012). Also median PFS in patients with a baseline phosphatase >220U/L was significantly better with combination treatment (9.0 months (95%CI 3.92-14.08) versus 6.2 months (95%CI 3.08-9.32); log rank p 0.005). As expected, thrombocytopenia (grade I/II) was reported more frequently in the experimental group (25% versus 0%).

CONCLUSION

Combined treatment with rhenium-188-HEDP and docetaxel did not prolong PFS in patients with CRPC. The observed survival benefit in the per-protocol analysis warrants further studies in the combined treatment of chemotherapy and radiopharmaceuticals.

Bone Health and Bone-targeted Therapies for Prostate Cancer: a Programme in Evidence-based Care - Cancer Care Ontario Clinical Practice Guideline

AIMS

To make recommendations with respect to bone health and bone-targeted therapies in men with prostate cancer.

MATERIALS AND METHODS

A systematic review was carried out by searching MEDLINE, EMBASE and the Cochrane Library from inception to January 2016. Systematic reviews and randomised-controlled trials were considered for inclusion if they involved therapies directed at improving bone health or outcomes such as skeletal-related events, pain and quality of life in patients with prostate cancer either with or without metastases to bone. Therapies included medications, supplements or lifestyle modifications alone or in combination and were compared with placebo, no treatment or other agents. Disease-targeted agents such as androgen receptor-targeted and chemotherapeutic agents were excluded. Recommendations were reviewed by internal and external review groups.

RESULTS

In men with prostate cancer receiving androgen deprivation therapy, baseline bone mineral density testing is encouraged. Denosumab should be considered for reducing the risk of fracture in men on androgen deprivation therapy with an increased fracture risk. Bisphosphonates were effective in improving bone mineral density, but the effect on fracture was inconclusive. No medication is recommended to prevent the development of first bone metastasis. Denosumab and zoledronic acid are recommended for preventing or delaying skeletal-related events in men with metastatic castration-resistant prostate cancer. Radium-223 is recommended for reducing symptomatic skeletal events and prolonging survival in men with symptomatic metastatic castration-resistant prostate cancer.

CONCLUSIONS

The recommendations represent a current standard of care that is feasible to implement, with outcomes valued by clinicians and patients.

Cardiovascular toxicities of systemic treatments of prostate cancer

Prostate cancer is the most common cancer in men, with an incidence that is expected to increase in the coming years. Prostate cancer is usually diagnosed in men >65 years of age, thus the concurrent presence of cardiovascular diseases might influence the treatment, owing to the increased risk of cardiovascular mortality. The introduction of new drugs, such as abiraterone and enzalutamide for the management of metastatic disease has created further interest in treatment-related cardiovascular toxicities, although limited data from trials specifically designed to identify cardiovascular toxicities of these agents are currently available. The only available data are derived from published phase II-III study reports, expanded access or compassionate use programmes and meta-analyses of the effects of systemic therapies that are already approved for use in clinical practice or are in the early phases of development. These data are conflicting, although they seem to suggest that certain drugs are associated with an increased risk of cardiovascular adverse events. Clinical trial methodology could be improved by the enrolment of greater numbers of patients >65 years of age, and the use of comprehensive cardiological evaluations. Moreover, closer collaboration between oncologists and cardiologists is essential for the identification and/or management of cardiovascular adverse events in patients with prostate cancer.

Patient experience in the treatment of metastatic castration-resistant prostate cancer: state of the science

Background:

Contemporary therapies for metastatic castration-resistant prostate cancer (mCRPC) have shown survival improvements, which do not account for patient experience and health-related quality of life (HRQoL).

Methods:

This literature review included a search of MEDLINE for randomized clinical trials enrolling ⩾50 patients with mCRPC and reporting on patient-reported outcomes (PROs) since 2010.

Results:

Nineteen of 25 publications describing seven treatment regimens (10 clinical trials and nine associated secondary analyses) met the inclusion criteria and were critically appraised. The most commonly used measures were the Functional Assessment of Cancer Therapy-Prostate (n=5 trials) and Brief Pain Inventory Short Form (n=4 trials) questionnaires. The published data indicated that HRQoL and pain status augmented the clinical efficacy data by providing a better understanding of treatment impact in mCRPC. Abiraterone acetate and prednisone, enzalutamide, radium-223 dichloride and sipuleucel-T offered varying levels of HRQoL benefit and/or pain mitigation versus their respective comparators, whereas three treatments (mitoxantrone, estramustine phosphate and docetaxel, and cabazitaxel) had no meaningful impact on HRQoL or pain. The main limitation of the data were that the PROs utilized were not developed for use in mCRPC patients and hence may not have comprehensively captured symptoms important to this population.

Conclusions:

Recently published randomized clinical trials of new agents for mCRPC have captured elements of the patient experience while on treatment. Further research is required to standardize methods for measuring, quantifying and reporting on HRQoL and pain in patients with mCRPC in the clinical practice setting.

Chemotherapy options in castration-resistant prostate cancer

Introduction:

The treatment landscape for patients with metastatic castration-resistant prostate cancer (CRPC) is evolving, with recent approvals of immune therapy, novel hormonal therapy, and bone-targeted therapy. Chemotherapy remains an essential component of the armamentarium. Herein, we review current chemotherapy options for patients with CRPC and discuss future challenges.

Methods:

We reviewed literature for chemotherapy agents in prostate cancer, with special attention to the evidence for efficacy of the currently approved agents. We also reviewed emerging data on biomarkers of response to chemotherapy for CRPC.

Results:

Taxanes, especially docetaxel and cabazitaxel, have first- and second-line indications for CRPC, respectively, with both providing a survival benefit. Multiple attempts to improve on the single agent efficacy of docetaxel with combination therapy have not generally been successful although platinum combinations are used for resistant phenotypes. Reductions in prostate-specific antigen by ≥30% and reductions in circulating tumor cells (CTCs) to ≤ 5 are associated with improved survival on chemotherapy. Chemotherapy may continue to be effective therapy for patients with biomarkers that are associated with resistance to androgen-directed therapies (androgen receptor splice variant 7 positivity in CTCs or high CTC heterogeneity).

Conclusions:

Chemotherapy remains an essential component of CRPC therapy, and biomarkers are being identified to define clinical scenarios where chemotherapy may be the optimal therapy choice.

Addressing the expected survival benefit for clinical trial design in metastatic castration-resistant prostate cancer: Sensitivity analysis of randomized trials

We performed a sensitivity analysis, cumulating all randomized clinical trials (RCTs) in which patients with metastatic castration-resistant prostate cancer (mCRPC) received systemic therapy, to evaluate if the comparison of RCTs may drive to biased survival estimations. An overall survival (OS) significant difference according to therapeutic strategy was more likely be determined in RCTs evaluating hormonal drugs versus those studies testing immunotherapy, chemotherapy or other strategies. With regard to control arm, an OS significant effect was found for placebo-controlled trials versus studies comparing experimental treatment with active therapies. Finally, regarding to docetaxel (DOC) timing, the OS benefit was more likely to be proved in Post-DOC setting in comparison with DOC and Pre-DOC. These data suggest that clinical trial design should take into account new benchmarks such as the type of treatment strategy, the choice of the comparator and the phase of the disease in relation to the administration of standard chemotherapy.

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

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

Bisphosphonates for cancer treatment: Mechanisms of action and lessons from clinical trials

A growing body of evidence points toward an important anti-cancer effect of bisphosphonates, a group of inexpensive, safe, potent, and long-term stable pharmacologicals that are widely used as osteoporosis drugs. To date, they are already used in the prevention of complications of bone metastases. Because the bisphosphonates can also reduce mortality in among other multiple myeloma, breast, and prostate cancer patients, they are now thoroughly studied in oncology. In particular, the more potent nitrogen-containing bisphosphonates have the potential to improve prognosis. The first part of this review will elaborate on the direct and indirect anti-tumoral effects of bisphosphonates, including induction of tumor cell apoptosis, inhibition of tumor cell adhesion and invasion, anti-angiogenesis, synergism with anti-neoplastic drugs, and enhancement of immune surveillance (e.g., through activation of γδ T cells and targeting macrophages). In the second part, we shed light on the current clinical position of bisphosphonates in the treatment of hematological and solid malignancies, as well as on ongoing and completed clinical trials investigating the therapeutic effect of bisphosphonates in cancer. Based on these recent data, the role of bisphosphonates is expected to further expand in the near future outside the field of osteoporosis and to open up new avenues in the treatment of malignancies.

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

BACKGROUND

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

METHODS

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

RESULTS

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

CONCLUSION

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

Circulating tumor cells in patients with metastatic castration resistant prostate cancer: exploratory findings at a tertiary referral hospital

Objectives

In patients with metastatic castration-resistant prostate cancer (mCRPC), the finding of less than five circulating tumor cells (CTCs)/7.5 mL blood before start of cytotoxic treatment or shortly thereafter indicates prolonged survival. In this descriptive pilot study, we investigated whether this association depends on the sequence of the therapeutic attempts.

Patients and methods

CTCs were determined in 41 mCRPC patients before and 2–3 months after starting first-line treatment with docetaxel (group 1) or second-line treatment with either radium-223 (group 2) or placebo/best supportive care (group 3). A “favorable” CTC count was defined as <5 CTC/7.5 mL blood. The results were related to overall survival.

Results

Pretreatment, six of ten men in group 1, three of 19 in group 2, and three of 12 patients in group 3 had a favorable CTC count, leading to a significant difference between first- and second-line therapy (P=0.04). Decrease of pretreatment elevated CTCs to a favorable CTC count was significantly more often observed in patients on first-line therapy (three of four patients) than on second-line treatment (two of 26 men) (P=0.03). A favorable CTC count before or shortly after treatment start was observed in nine of ten patients on first-line and in eight of 31 men on second-line therapy (P=0.01). A favorable CTC count pretreatment or 2–3 months after therapy start was associated with beneficial overall survival in the three groups combined and in each group analyzed separately.

Conclusion

In mCRPC, a favorable CTC count before or 2–3 months after start of therapy is associated with length of overall survival, though such favorable CTC counts are observed significantly less often in patients on second- than on first-line therapy.

Quo vadis: advanced prostate cancer-clinical care and clinical research in the era of multiple androgen receptor-directed therapies

The novel androgen receptor-directed therapies abiraterone acetate and enzalutamide, having demonstrated improved survival in randomized phase 3 studies of men with metastatic castration-resistant prostate cancer, have ushered in a new era in the treatment of this disease. Additional novel androgen receptor-directed therapies, such as ARN-509 and orteronel, are in various phases of clinical trials and development. However, the emergence of therapeutic resistance and clinical disease progression is inevitable. Although advances in genomic technologies have led to unprecedented understanding of the biology of castration-resistant prostate cancer, efforts only now are underway to elucidate the mechanisms of resistance associated with abiraterone and enzalutamide. A tremendous challenge in the near future will be to determine the optimal sequence or combination of therapies to overcome resistance mechanisms. In this review, the current landscape of androgen receptor-directed therapies and future directions necessary to enhance their clinical efficacy for the maximal benefit of patients are discussed.

Achievements and perspectives in prostate cancer phase 3 trials from genitourinary research groups in Europe: introducing the Prostate Cancer Consortium in Europe

CONTEXT

Phase 3 trials have made major contributions to advances in prostate cancer (PCa). However, funding limitations and excess bureaucracy are now making it difficult to conduct trials.

OBJECTIVE

To describe the collaborative groups in Europe and their academic phase 3 PCa trials.

EVIDENCE ACQUISITION

Leaders of collaborative groups from Scandinavia, the European Organisation for Research and Treatment of Cancer (EORTC), France, Spain, the United Kingdom, Germany, Switzerland, The Netherlands, and Ireland were asked to provide information.

EVIDENCE SYNTHESIS

Approximately 40 academic European phase 3 trials focussing on PCa have been completed, and about 10 are accruing patients. Cross-border trials have been successfully conducted led by EORTC (11), Scandinavian Prostate Cancer Group (9), European Association of Urology (1), Systemic Therapy in Advancing or Metastatic Prostate Cancer: Evaluation of Drug Efficiency (STAMPEDE) (1), and the French Genito-Urinary Tumor Group (1). Among these studies were practise-changing trials showing the superiority of prostatectomy over watchful waiting in patients <65 yr of age, the benefits of combining androgen-deprivation therapy (ADT) with radiation therapy (RXT) in high-risk localised disease, the superiority of long-term versus short-term ADT, the benefit of RXT in men treated with ADT, and the role of adjuvant RXT. To bridge the numbers gap for phase 3 studies, the Prostate Cancer Consortium in Europe (PEACE) is a recently established initiative that aims to favour cross-border networks of investigators. PEACE 1 is testing the addition of abiraterone and that of RXT directed at the primary cancer in patients with de novo metastatic PCa treated with ADT. PEACE 2 is testing the addition of cabazitaxel and that of pelvic irradiation in patients with at least two criteria for high-risk localised PCa.

CONCLUSIONS

European academic phase 3 trials have contributed to establishing the current standard treatment of PCa. The PEACE consortium was recently tasked with the goal of addressing unanswered questions and specific biology-related issues more efficiently.

PATIENT SUMMARY

The Prostate Cancer Consortium in Europe was established to conduct comparative trials aiming at assessing new treatments for prostate cancer patients.

PSA response rate as a surrogate marker for median overall survival in docetaxel-based first-line treatments for patients with metastatic castration-resistant prostate cancer: an analysis of 22 trials

The aim of this study was to determine the correlation between PSA response rate (PSA RR) and overall survival (OS) and identify PSA RR as a potential surrogate for OS, in docetaxel-based first-line treatments for castration-resistant prostate cancer (CRPC). Trials of first-line regimens with docetaxel for patients with metastatic CRCP published between 2004 and 2013 were identified, and data were evaluated statistically in order to investigate the correlation between PSA RR and OS. A total of 22 trials were identified and included in our analysis, for a total of 7,677 patients. In addition, we divided all the trails and arms of the randomized trials in two subgroups, the first one composed only of docetaxel (D) plus prednisone (P) regimens (standard therapy) and the second one composed of all D + other drug combinations (D combinations). Analysing all the trials and arms as a single unit, we found a statistically significant correlation between PSA RR and OS, with Spearman's rank correlation coefficient ρ = 0.50 (95% confidence interval (CI), 0.47 to 0.88) (P = 0.003). Also evaluating the standard therapy group, we found a statistically significant correlation between PSA RR and OS, with Spearman's ρ = 0.65 (95% CI, 0.38 to 0.70) (P = 0.02). However, when we assessed the D combination group, we found Spearman's rank correlation coefficient decreased (ρ = 0.42) (95% CI, 0.28 to 0.80) and resulted nonstatistically significant (P = 0.06). In conclusion, we found a statistically significant correlation between PSA RR and OS. The usage of PSA RR as a surrogate marker for OS in metastatic CRPC patients treated with D-based first-line regimens may be appropriate only in the D + P combination.

Future of bisphosphonates and denosumab for men with advanced prostate cancer

Prostate cancer is the most common cancer occurring in American men of all races. It is also the second leading cause of cancer death among men in the USA. Bone metastasis is a frequent occurrence in men with advanced prostate cancer, with skeletal-related events being a common complication and having negative consequences, leading to severe pain, increased health care costs, increased risk of death, and decreased quality of life for patients. Bone loss can also result from antiandrogen therapy, which can further contribute to skeletal-related events. Treatment with antiresorptive agents bisphosphonates, and the newly approved denosumab, a receptor activator of nuclear factor kappa-B ligand (RANK-L) inhibitor, has been shown to reduce the risk of skeletal-related complications and prevent treatment-induced bone loss in patients with advanced prostate cancer. This review discusses the role of antiresorptive agents bisphosphonates and RANK-L inhibitor in the current treatment of advanced prostate cancer by examining the primary literature and also focuses on the likely role of the bisphosphonates in the treatment of advanced prostate cancer in the future.

Analysis of docetaxel therapy in elderly (≥70 years) castration resistant prostate cancer patients enrolled in the Netherlands Prostate Study

BACKGROUND

Prostate cancer truly is an age-associated disease. Due to the increased life expectancy and more sensitive diagnostic techniques in the Western world, prostate cancer is diagnosed more frequently and with rapidly increasing incidence and prevalence rates. However, age above 65 or 70 years has been an exclusion criterion in clinical trials for decades and the knowledge about chemotherapy tolerance in elderly is limited.

METHODS

We performed a retrospective analysis of data acquired from the recently published Netherlands Prostate Study (NePro) to evaluate the influence of advanced age on docetaxel therapy in elderly men (>70 years) with castration resistant prostate cancer (CRPC) and bone metastases. Statistical analyses were performed stratified for age into four categories: <70 (n=315), 70-74 (n=150), 75-79 (n=85), and ≥80 years old (n=18).

RESULTS

We analysed 568 patients (median age 68.1 years, range 46-89 years, 44.5% aged ≥70 years). There was no relation between dosage and age (p=0.60). We found no significant differences between the number of dose reductions, time to progression (TTP), overall survival, chemotherapy tolerance and toxicity up to the age of 80 years. However, when compared to younger men, men aged 80 years or above more frequently experienced grade 3/4 toxicity and were five times less likely to complete the first three treatment cycles at the intended dose (Odds ratio (OR) 5.34, p=0.0052) and showed decreased overall survival (15.3 months versus 24.5 months in <80 years group, p=0.020).

CONCLUSION

In CRPC patients up to the age of 80 years, docetaxel chemotherapy is well tolerated, with toxicity levels and TTP comparable to those of younger patients. For chemotherapeutic treatment of patients above the age of 80 years an individual assessment should be made.

Nanotechnology in the targeted drug delivery for bone diseases and bone regeneration

Nanotechnology is a vigorous research area and one of its important applications is in biomedical sciences. Among biomedical applications, targeted drug delivery is one of the most extensively studied subjects. Nanostructured particles and scaffolds have been widely studied for increasing treatment efficacy and specificity of present treatment approaches. Similarly, this technique has been used for treating bone diseases including bone regeneration. In this review, we have summarized and highlighted the recent advancement of nanostructured particles and scaffolds for the treatment of cancer bone metastasis, osteosarcoma, bone infections and inflammatory diseases, osteoarthritis, as well as for bone regeneration. Nanoparticles used to deliver deoxyribonucleic acid and ribonucleic acid molecules to specific bone sites for gene therapies are also included. The investigation of the implications of nanoparticles in bone diseases have just begun, and has already shown some promising potential. Further studies have to be conducted, aimed specifically at assessing targeted delivery and bioactive scaffolds to further improve their efficacy before they can be used clinically.

Antimitotic agents for the treatment of patients with metastatic castrate-resistant prostate cancer

INTRODUCTION

Metastatic castrate-resistant prostate cancer (mCRPC) is the second deadliest cancer in men. The group of taxanes, which target microtubules of mitotic cells, is currently the only chemotherapy which has proven to increase overall survival in mCRPC patients. Other mitotic inhibitors are being explored for their clinical potential in mCRPC treatment.

AREAS COVERED

In this review, we summarize recent developments in the application of mitotic inhibitors for mCRPC from a clinical perspective. The four main groups of mitotic inhibitors currently being tested in clinical trials are microtubule-inhibitors, polo-like kinase 1 inhibitors, aurora kinase inhibitors and kinesin-spindle protein inhibitors. Compounds of these groups of inhibitors that are in clinical development for mCRPC are discussed. For this extensive overview, relevant literature was searched in PubMed and retrieved from clinicaltrials.gov and presentations at ASCO/AACR meetings.

EXPERT OPINION

In general, mitotic inhibitors are clinically well tolerated but exert limited antitumor activity compared to preclinical study results. However, efficacy of mitotic inhibitors is improving, either by personalizing treatment, by introducing more active compounds, by decreasing resistance of cancer cells against mitotic inhibitors or by using mitotic inhibitors in combination therapies.