New treatment developments applied to elderly patients with advanced prostate cancer

Sasanquasaponin inhibited epithelial to mesenchymal transition in prostate cancer by regulating the PI3K/Akt/mTOR and Smad pathways

CONTEXT

Sasanquasaponin (SQS) is a commonly used traditional Chinese medicine proved to have a wide range of pharmacological functions.

OBJECTIVE

The objective of this study is to explore the effect and underlying mechanism of SQS in the treatment of prostate cancer (PC).

MATERIALS AND METHODS

PC cell lines (22Rv1 and PC-3) were treated with SQS (0, 0.5, 1, 2, and 4 μM) for 12 or 24 h. The viability of cells was evaluated, while the mRNA and protein levels of epithelial to mesenchymal transition (EMT)-related genes in PC cell lines were measured (Groups: Control, TGF-β1, TNF-α, TGF-β1 + TNF-α, and TGF-β1 + TNF-α + SQS). The migration and invasion abilities of PC cell lines were evaluated (Groups: Control, SQS). Finally, the antitumour effect of SQS (25, 50,100, and 200 mg/kg) in BALB/c nude mice (6 weeks, 18-20 g) was evaluated (Groups: Control, Vehicle, 25, 50,100, and 200 mg/kg SQS). The study duration was 1 month.

RESULTS

SQS inhibited the viability and the number of colonies of 22Rv1 or PC-3 cells. The IC₅₀ of SQS of 12 and 24 h in these two cells was 3.25, 1.82, 4.76, and 4.70 μM, respectively. SQS inhibited the adhesion, migration, and invasion of PC cells. It also inhibited the expression of EMT-related markers of PC cells. The PI3K/Akt/mTOR and Smad2/3 signalling pathways were activated in the process of EMT, and SQS could significantly reduce the activation of the PI3K/Akt/mTOR and Smad2/3 pathways. Finally, SQS inhibited the growth of xenograft tumours in vivo.

CONCLUSIONS

SQS inhibited EMT in PC by regulating the PI3K/Akt/mTOR and Smad pathways.

Breviscapine suppresses the growth and metastasis of prostate cancer through regulating PAQR4-mediated PI3K/Akt pathway

OBJECTIVES

Prostate cancer, one of the most frequently diagnosed tumors of men, leads to poor quality of life. Previous studies have shown that breviscapine (BRE) exerts therapeutic activity in malignant tumors. However, the role and mechanism of BRE exhibit an anti-tumor effect on prostate cancer are largely unknown.

METHODS

The mRNA and protein levels in prostate cancer tissues and cell lines were measured using RT-qPCR, western blot, and immunohistochemical staining, respectively. Cell proliferation, invasion, and migration in both PC3 and DU145 cells were evaluated using CCK-8 and Transwell assay. The effect of BRE on cell proliferation and metastasis by regulating the PAQR4-mediated PI3K/Akt pathway in vitro and in vivo was determined.

RESULTS

PAQR4 was significantly overexpressed in prostate cancer tissues and cell lines, which was positively correlated with poor prognosis. Knockdown of PAQR4 inhibited the proliferation, invasion, migration, and epithelial-mesenchymal transition (EMT) of both PC3 and DU145 cells. Mechanistically, BRE treatment significantly suppressed the malignant biological behavior of both prostate cancer cells by downregulating PAQR4 and blocking the PI3K/Akt pathway. In vivo experiments, BRE administration remarkably inhibited tumor growth and metastasis in a xenograft model of prostate cancer.

CONCLUSION

Our findings revealed that BRE exerts anti-tumor and anti-metastasis roles in prostate cancer by inhibiting PAQR4-mediated PI3K/Akt pathway, which provides a new therapeutic agent for prostate cancer clinical treatment.

Age, Gleason Score, and PSA are important prognostic factors for survival in metastatic castration-resistant prostate cancer. Results of The Uroncor Group (Uro-Oncological Tumors) of the Spanish Society of Radiation Oncology (SEOR)

INTRODUCTION

The treatment of metastatic castration-resistant prostate cancer (mCRPC) has changed significantly in recent years. Inhibitors of androgen receptors have shown especially significant benefits in overall (OS) and progression-free survival (PFS), with a good toxicity profile. Treatment selection depends on the patient's individual clinical, radiological, and biological characteristics.

OBJECTIVE

To describe treatment outcomes (efficacy, toxicity) in a cohort of patients with mCRPC in Spain.

MATERIALS AND METHODS

Multicenter, retrospective study of patients with mCRPC included in a database of the Urological Tumour Working Group (URONCOR) of the Spanish Society of Radiation Oncology (SEOR). Metastatic CRPC was defined according to the prostate cancer working group 3 (PCWG3) criteria. The Kaplan-Meier technique was used to evaluate OS and the Common Terminology Criteria for Adverse Events (CTCAE, v.4.0) were used to assess toxicity. Univariate and multivariate Cox regression analyses were performed to identify the factors significantly associated with OS.

RESULTS

A total of 314 patients from 17 hospitals in Spain diagnosed with mCRPC between June 2010 and September 2017 were included in this study. Mean age at diagnosis was 68 years (range 45-89). At a median follow-up of 35 months, OS at 1, 3, and 5 years were 92%, 38%, and 28%, respectively. Grades 1-2 and grade 3 toxicity rates were, respectively, 68% and 19%. No grade 4 toxicities were observed. On the multivariate analysis, the following factors were significantly associated with OS: age (hazard ratio [HR] 0.42, p = 0.010), PSA value at diagnosis of mCRPC (HR 0.55, p = 0.008), and Gleason score (HR 0.61, p = 0.009).

CONCLUSIONS

Age, Gleason score, and PSA at diagnosis of mCRPC are independently associated with overall survival in patients with mCRPC. The efficacy and toxicity outcomes in this patient cohort treated in radiation oncology departments in Spain are consistent with previous reports.

Safety and outcomes of new generation hormone-therapy in elderly chemotherapy-naive metastatic castration-resistant prostate cancer patients in the real world

BACKGROUND

Abiraterone acetate and enzalutamide are standard treatments for chemotherapy-naive metastatic castration-resistant prostate cancer (CN-mCRPC). The purpose of this study was to evaluate the effectiveness and safety of these medications in elderly (≥ 75 years old) compared with young CN-mCRPC patients in a real-world clinical setting. Secondarily, we explored the survival prognostic value of different anatomo-clinical factors in elderly group.

METHODS

In this retrospective observational multicentre study, we included 134 consecutive CN-mCRPC patients, 64 young and 70 elderly men, who had received AA or Enz.

RESULTS

We did not find significant differences in treatment duration [16.6 months, (95% CI 9-24.2 months) vs. 16.8 months (95% CI: 6.3-27.2 months); p = 0.926] and overall survival [median not reached vs. 23.3 months (95% CI 10.2-36.3 months); p = 0.131] between the young and elderly groups. In elderly group, the only predictors of overall survival with AA or Enz were good ECOG performance status and high G8 score. Adverse events of grade ≥3 was similar in elderly group (12.9%) and in the young group (15.6%). Treatment was discontinued due to AEs in 6.3% of young group and 18.6% of elderly group.

CONCLUSIONS

Effectiveness and safety of treatment of CN-mRCPC with Abiraterone acetate and enzalutamide were similar in older and younger patients, although treatment discontinuation due to AEs was more frequent in the older age group. In addition to ECOG PS, assessment using specific geriatric scales as G8 screening tool could help to identify patients aged ≥75 who would most benefit from treatment with new-generation hormone therapy.

No significant impact of patient age and prior treatment profile with docetaxel on the efficacy of cabazitaxel in patient with castration-resistant prostate cancer

BACKGROUND

The correlation of the oncological outcomes of docetaxel and cabazitaxel in Japanese metastatic castration-resistant prostate cancer (mCRPC) patients has not been unclear.

MATERIALS AND METHODS

This study included a total of 47 consecutive Japanese mCRPC patients treated with cabazitaxel and assessed the prognostic significance of cabazitaxel, focusing on patient age and the correlation of efficacy between docetaxel and cabazitaxel.

RESULTS

Prostate-specific antigen (PSA) decline was observed in 27 patients (57.4%), including 19 (40.0%) achieving the response defined by PSA decline ≥ 30%. The median overall survival (OS) periods after the introduction of cabazitaxel was 16.1 months. Twenty (42.6%) were judged to have responded to cabazitaxel with a PSA decrease ≥ 30% from the baseline. A 30% PSA response to cabazitaxel was achieved in 4 (50.0%) patients with ≧ 75 years (n = 8) and 16 (41.0%) patients with less than 75 years (n = 39). There was no significant correlation between the PSA response and patients' age (p = 0.707). A 30% PSA response to cabazitaxel was achieved in 13 (46.4%) and 7 (36.8%) patients with and without that to docetaxel, respectively. A 30% PSA response to cabazitaxel was achieved in 5 (16.6%) and 7 (41.2%) patients who had treated with less than 10 cycles docetaxel or 10 ≦ cycles, respectively. Univariate and multivariate analyses revealed that there were no significant correlation of patient age (p = 0.537), the response to prior docetaxel therapy (p = 0.339) or cycles of docetaxel therapy (p = 0.379) with shorter OS.

CONCLUSION

These results indicate that the introduction of cabazitaxel for Japanese mCRPC patients could result in oncological outcomes without any association with patient's age and the profiles of previous docetaxel therapy.

Subsequent Chemotherapy and Treatment Patterns After Abiraterone Acetate in Patients with Metastatic Castration-resistant Prostate Cancer: Post Hoc Analysis of COU-AA-302

BACKGROUND

Treatment patterns for metastatic castration-resistant prostate cancer (mCRPC) have changed substantially in the last few years. In trial COU-AA-302 (chemotherapy-naïve men with mCRPC), abiraterone acetate plus prednisone (AA) significantly improved radiographic progression-free survival and overall survival (OS) when compared to placebo plus prednisone (P).

OBJECTIVE

This post hoc analysis investigated clinical responses to docetaxel as first subsequent therapy (FST) among patients who progressed following protocol-specified treatment with AA, and characterized subsequent treatment patterns among older (≥75 yr) and younger (<75 yr) patient subgroups.

DESIGN, SETTING, AND PARTICIPANTS

Data were collected at the final OS analysis (96% of expected death events). Subsequent therapy data were prospectively collected, while response and discontinuation data were collected retrospectively following discontinuation of the study drug.

INTERVENTION

At the discretion of the investigator, 67% (365/546) of patients from the AA arm received subsequent treatment with one or more agents approved for mCRPC.

OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS

Efficacy analysis was performed for patients for whom baseline and at least one post-baseline prostate-specific antigen (PSA) values were available.

RESULTS AND LIMITATIONS

Baseline and at least one post-baseline PSA values were available for 100 AA patients who received docetaxel as FST. While acknowledging the limitations of post hoc analyses, 40% (40/100) of these patients had an unconfirmed ≥50% PSA decline with first subsequent docetaxel therapy, and 27% (27/100) had a confirmed ≥50% PSA decline. The median docetaxel treatment duration among these 100 patients was 4.2 mo. Docetaxel was the most common FST among older and younger patients from each treatment arm. However, 43% (79/185) of older patients who progressed on AA received no subsequent therapy for mCRPC, compared with 17% (60/361) of younger patients.

CONCLUSIONS

Patients with mCRPC who progress with AA treatment may still derive benefit from subsequent docetaxel therapy. These data support further assessment of treatment patterns following AA treatment for mCRPC, particularly among older patients.

TRIAL REGISTRATION

ClinicalTrials.gov NCT00887198.

PATIENT SUMMARY

Treatment patterns for advanced prostate cancer have changed substantially in the last few years. This additional analysis provides evidence of clinical benefit for subsequent chemotherapy in men with advanced prostate cancer whose disease progressed after treatment with abiraterone acetate. Older patients were less likely to be treated with subsequent therapy.

Treatment evolution for metastatic castration-resistant prostate cancer with recent introduction of novel agents: retrospective analysis of real-world data

Despite increasing drug treatment options for metastatic castration‐resistant prostate cancer (mCRPC) patients, real‐world treatment data are lacking. We conducted retrospective analyses of commercial claims and electronic medical record (EMR) databases to understand how treatment patterns for mCRPC have changed in a US‐based real‐world population. Truven Health Analytics MarketScan^® (2000–2013) and EMR (2004–2013) databases were used to identify patients with an index prostate cancer diagnosis (ICD‐9 codes 185X or 233.4X) and prescription claims for an mCRPC drug (mitoxantrone, estramustine, docetaxel, sipuleucel‐T, cabazitaxel, abiraterone acetate, enzalutamide, or radium‐223). Regimen analyses for first line of therapy (LOT1), second line of therapy, and beyond were performed among cohorts based on year of first mCRPC drug usage. mCRPC drug usage and treatment duration were compared across cohorts and age groups within each cohort. The commercial claims cohort yielded 3437 evaluable patients. Most men (91%) commencing mCRPC treatment had docetaxel as LOT1 in 2010; this number had declined to 15% in 2013. In 2013, 67% and 9% of patients used abiraterone acetate and enzalutamide, respectively, as LOT1. Among both commercial claims and EMR cohorts, treatment pattern changes were most pronounced in men aged >80 years, and median treatment duration for some mCRPC drugs was shorter than expected based on available clinical trial information. These results demonstrate a shift in mCRPC treatments during the past 5 years, with greater use of newer noncytotoxic treatments than docetaxel. These real‐world data aid in understanding the changing role of chemotherapy in the management of mCRPC.

Gene microarray assessment of multiple genes and signal pathways involved in androgen-dependent prostate cancer becoming androgen independent

To study the gene expression change and possible signal pathway during androgen-dependent prostate cancer (ADPC) becoming androgen-independent prostate cancer (AIPC), an LNCaP cell model of AIPC was established using flutamide in combination with androgen-free environment inducement, and differential expression genes were screened by microarray. Then the biological process, molecular function and KEGG pathway of differential expression genes are analyzed by Molecule Annotation System (MAS). By comparison of 12,207 expression genes, 347 expression genes were acquired, of which 156 were up-ragulated and 191 down-regulated. After analyzing the biological process and molecule function of differential expression genes, these genes are found to play crucial roles in cell proliferation, differntiation, cell cycle control, protein metabolism and modification and other biological process, serve as signal molecules, enzymes, peptide hormones, cytokines, cytoskeletal proteins and adhesion molecules. The analysis of KEGG show that the relevant genes of AIPC transformation participate in glutathione metabolism, cell cycle, P53 signal pathway, cytochrome P450 metabolism, Hedgehog signal pathway, MAPK signal pathway, adipocytokines signal pathway, PPAR signal pathway, TGF-β signal pathway and JAK-STAT signal pathway. In conclusion, during the process of ADPC becoming AIPC, it is not only one specific gene or pathway, but multiple genes and pathways that change. The findings above lay the foundation for study of AIPC mechanism and development of AIPC targeting drugs.

Efficacy and Safety of Abiraterone Acetate in Elderly (75 Years or Older) Chemotherapy Naïve Patients with Metastatic Castration Resistant Prostate Cancer

PURPOSE

Metastatic castration resistant prostate cancer primarily affects elderly men. In this post hoc analysis we investigated the safety and efficacy of abiraterone acetate in elderly (age 75 years or greater) and younger (less than 75 years) patient subgroups at the prespecified interim analysis (55% of total overall survival events) for the COU-AA-302 (Abiraterone Acetate in Asymptomatic or Mildly Symptomatic Patients with Metastatic Castration-Resistant Prostate Cancer) trial.

MATERIALS AND METHODS

Patients were stratified and randomized 1:1 to abiraterone acetate 1,000 mg plus prednisone/prednisolone 5 mg twice daily (abiraterone-prednisone) vs placebo plus prednisone/prednisolone 5 mg twice daily (prednisone alone). Co-primary end points were radiographic progression-free and overall survival. Median time to event and HR were estimated using the Kaplan-Meier method and a Cox model, respectively.

RESULTS

A total of 350 elderly patients treated with abiraterone-prednisone had significant improvements in overall and radiographic progression-free survival vs those with prednisone alone (HR 0.71, 95% CI 0.53-0.96 vs HR 0.63, 95% CI 0.48-0.83), similar to 738 younger patients (HR 0.81, 95% CI 0.63-1.03 vs HR 0.49, 95% CI 0.40-0.59). All secondary end points favored the abiraterone-prednisone arm for both age subgroups. Specific adverse events with abiraterone-prednisone were similar between the age subgroups. Elderly patients in both treatment arms had higher rates of fluid retention and cardiac disorders than younger patients, although rates of dose reduction or treatment interruptions due to adverse events were low in both age subgroups.

CONCLUSIONS

Abiraterone acetate demonstrated clinical benefit and was well tolerated in elderly and younger men with chemotherapy naïve, metastatic castration resistant prostate cancer. Thus, findings support it as a treatment option for elderly patients who may not tolerate other therapies with greater toxicity.

Pigment epithelium-derived factor expression prolongs survival and enhances the cytotoxicity of low-dose chemotherapy in castration-refractory prostate cancer

There is currently no cure for advanced castration-refractory prostate cancer (CRPC) despite the recent approval of several new therapeutic agents. We report here the anti-tumor effect of the angio-inhibitory pigment epithelium-derived factor (PEDF) in the metastatic LNCaP-derivative CRPC CL1 model and explore PEDF anti-neoplasic efficacy in combination with low-dose chemotherapy. Androgen-sensitive LNCaP and CRPC PC3 cell lines were examined as comparison. Using a retroviral expression system, we showed that PEDF limited the proliferation of all prostatic cell lines tested; an effect attributed to interleukin 8 (IL8)-CXCR1/IL8RA inhibition. PEDF also reduced the number and size of 3D tumor spheroids in vitro, but only induced cell differentiation in CRPC spheroids. Similarly, PEDF inhibited the migration of CRPC cells suggesting both anti-proliferative and anti-migratory functions. In vivo, PEDF decreased by 85% and 65% the growth of subcutaneous (s.c.) PC3 and CL1 tumors, respectively. In the CL1 orthotopic model, tumor intake with lethal metastases was found in all animals; nevertheless, PEDF prolonged the median survival of tumor-bearing mice (95% confidence interval: 53±0.001 to 57±1 days). Accordingly, PEDF delayed the emergence of skeletal-related event in intra-tibial xenografts. Next, we evaluated low-dose docetaxel (DTX; 5, 1, 0.5 mg/kg) or cyclophosphamide (CTX; 10–20 mg/kg) on established s.c. PC3 tumors that conditionally express PEDF anti-tumoral epitope/NT3. Although NT3–DTX-5 mg/kg combination was inefficient, NT3–DTX-1 mg/kg and -0.5 mg/kg inhibited by 95% and 87.8%, respectively, tumor growth compared with control and induced tumor stasis. Both NT3–CTX combinations were advantageous. Inversely, PEDF–DTX-5 mg/kg and PEDF–CTX-10 mg/kg delayed the most CL1 tumor growth (15, 11 and 5 days for PEDF–DTX-5 mg/kg, PEDF–CTX-10 mg/kg and single treatments, respectively) with elevated apoptosis and serum thrombospondin-1 as possible mechanism and marker, respectively. As well, both PEDF–CTX-10 mg/kg and PEDF–DTX-5 mg/kg prolonged significantly the survival of tumor-bearing mice compared with single treatments. Metastases were reduced in PEDF–DTX-5 mg/kg compared with other treatments, suggesting that PEDF–DTX delayed metastases formation. Our results advocate that PEDF/low-dose chemotherapy may represent a new therapeutic alternative for CRPC.

Chemotherapeutic inhibitors in the treatment of prostate cancer

INTRODUCTION

Prostate cancer being the second leading cause of death in men in Western countries remains a major challenge in healthcare. Several novel agents targeting signaling pathways in prostate cancer have recently been approved by the US Food and Drug Administration (FDA) but there is still an unmet need for new treatment strategies for castration-resistant prostate cancer (CRPC).

AREAS COVERED

This review provides a broad overview of prostate cancer therapeutics and highlights key players in the biology of prostate cancer as well as first- and second-line treatments for CRPC. Keywords 'chemotherapeutic agents', 'prostate cancer', 'Phase III clinical trials' and 'US FDA approval' were used for search in PubMed and clinicalTrials.gov databases and the obtained literature was reviewed and summarized.

EXPERT OPINION

Owing to the advances in screening and diagnostic techniques, the majority of prostate cancer cases are diagnosed at an early stage resulting in an almost 100% 5-year survival rate. Recently FDA-approved novel agents (e.g., abiraterone acetate and enzalutamide) have provided new hope in the fight against prostate cancer. However, CRPC remains an incurable disease. Identification of mechanisms of resistance, new biomarkers, appropriate clinical trial end points and novel treatments holds the key for the future of prostate cancer therapy.

Castration-resistant prostate cancer: from new pathophysiology to new treatment

CONTEXT

Until recently, the only approved agent for metastatic castration-resistant prostate cancer (mCRPC) was docetaxel chemotherapy. But over the last 5 years, significant advances in the field have led to the approval of five new agents, each with different mechanisms of action and demonstrating improved overall survival in separate randomized phase 3 trials. Many of these novel agents are now also being evaluated in earlier stages of the disease, which may ultimately lead to even better outcomes.

OBJECTIVE

To summarize the current literature on the management of mCRPC with a particular focus on novel chemotherapy approaches, hormonal approaches, immunotherapy, and radiopharmaceuticals showing survival benefits in phase 3 clinical trials. Emerging therapies in late stages of development are also discussed briefly.

EVIDENCE ACQUISITION

A comprehensive search of PubMed, identified studies pertaining to novel therapies evaluated in mCRPC since the initial approval of docetaxel in 2004. Abstracts from major international meetings were hand searched to identify studies of novel agents in late stage development in mCRPC. The Clinical Trials.gov database was used to find ongoing clinical trials in the area of mCRPC. A detailed search of each new agent was also performed to ensure that additional trials of these agents in other stages of the disease were included where relevant.

EVIDENCE SYNTHESIS

The main agents discussed are the androgen synthesis inhibitor abiraterone acetate, the androgen receptor inhibitor enzalutamide, the novel taxane chemotherapy cabazitaxel, the immunotherapy sipuleucel-T, and the radiopharmaceutical radium 223. Other emerging agents and a brief discussion of negative phase 3 results are also included.

CONCLUSIONS

It is a very exciting time in the field of mCRPC, where therapeutic advances have improved outcomes in this disease, although once metastatic overall median survival remains a dismal 2-3 years. The key now will be to understand how best to use these new agents, understand the mechanisms of resistance to them, continue to develop novel treatment strategies, and ultimately test these agents earlier in the disease when cure may be possible.