Optimizing the care of patients with advanced prostate cancer in the UK: current challenges and future opportunities

Signs and symptoms in relation to progression, experiences of an uncertain illness situation in men with metastatic castration-resistant prostate cancer-A qualitative study

OBJECTIVE

Signs and symptoms are important in monitoring prostate cancer, but there is a lack of understanding about the men's interpretation of signs and symptoms in relation to disease progression in advanced phases of the disease. The aim was to illuminate the experience of signs and symptoms in relation to disease progression in men with metastatic castration-resistant prostate cancer (mCRPC).

METHOD

Thirty longitudinal interviews were conducted with 11 men undergoing life-prolonging treatment for mCRPC. Conventional content analysis was used.

RESULTS

The results illuminate an uncertainty that the men experience when interpreting signs and symptoms. The overarching theme was The experience of an uncertain illness situation within the framework of progression, with four subthemes: Symptoms triggering thoughts about disease progression; Making sense of signs, also in the absence of symptoms; Making sense of symptoms during treatment; Progression triggering thoughts about the remainder of life.

CONCLUSION

In the uncertain illness situation, the men strive to make sense of signs and symptoms based on previous experiences and in relation to disease progression. Understanding the men's perspectives on signs and symptoms in this late phase may help health care professionals communicate about disease progression considering the balance between treatment outcome and quality of life.

Systematic Development of Solid Lipid Nanoparticles of Abiraterone Acetate with Improved Oral Bioavailability and Anticancer Activity for Prostate Carcinoma Treatment

In the present work, an attempt was undertaken to improve the oral bioavailability and anticancer activity of abiraterone acetate. Solid lipid nanoparticles (SLNs) were developed using the quality by design (QbD) principles and evaluated through in vitro, ex vivo, and in vivo studies. Solid lipid suitability was evaluated by equilibrium solubility study, while surfactant and cosurfactant were screened based on the ability to form microemulsion with the selected lipid. SLNs were prepared by emulsion/solvent evaporation method using glyceryl monostearate, Tween 80, and Poloxamer 407 as the solid lipid, surfactant, and cosurfactant, respectively. Box-Behnken design was applied for optimization of material attributes and evaluating their impact on particle size, polydispersity index, zeta potential, and entrapment efficiency of the SLNs. In vitro drug release study was evaluated in simulated gastric and intestinal fluids. Cell culture studies on PC-3 cells were performed to evaluate the cytotoxicity of the drug-loaded SLNs in comparison to the free drug suspension. Qualitative uptake was evaluated for Rhodamine B-loaded SLNs and compared with free dye solution. Ex vivo permeability was evaluated on Wistar rat intestine and in vivo pharmacokinetic evaluation on Wistar rats for SLNs and free drug suspension. Concisely, the SLNs showed potential for significant improvement in the biopharmaceutical performance of the selected drug candidate over the existing formulations of abiraterone acetate.

Sintokamide A Is a Novel Antagonist of Androgen Receptor That Uniquely Binds Activation Function-1 in Its Amino-terminal Domain

Androgen receptor (AR) is a validated drug target for all stages of prostate cancer including metastatic castration-resistant prostate cancer (CRPC). All current hormone therapies for CRPC target the C-terminal ligand-binding domain of AR and ultimately all fail with resumed AR transcriptional activity. Within the AR N-terminal domain (NTD) is activation function-1 (AF-1) that is essential for AR transcriptional activity. Inhibitors of AR AF-1 would potentially block most AR mechanisms of resistance including constitutively active AR splice variants that lack the ligand-binding domain. Here we provide evidence that sintokamide A (SINT1) binds AR AF-1 region to specifically inhibit transactivation of AR NTD. Consistent with SINT1 targeting AR AF-1, it attenuated transcriptional activities of both full-length AR and constitutively active AR splice variants, which correlated with inhibition of growth of enzalutamide-resistant prostate cancer cells expressing AR splice variants. In vivo, SINT1 caused regression of CRPC xenografts and reduced expression of prostate-specific antigen, a gene transcriptionally regulated by AR. Inhibition of AR activity by SINT1 was additive to EPI-002, a known AR AF-1 inhibitor that is in clinical trials (NCT02606123). This implies that SINT1 binds to a site on AF-1 that is unique from EPI. Consistent with this suggestion, these two compounds showed differences in blocking AR interaction with STAT3. This work provides evidence that the intrinsically disordered NTD of AR is druggable and that SINT1 analogs may provide a novel scaffold for drug development for the treatment of prostate cancer or other diseases of the AR axis.

Sipuleucel-T (Provenge(®))-Autopsy of an Innovative Paradigm Change in Cancer Treatment: Why a Single-Product Biotech Company Failed to Capitalize on its Breakthrough Invention

Approved by the US Food and Drug Administration (FDA) in 2010, sipuleucel-T (Provenge(®)) was the first 'personalized' cancer vaccine for the treatment of prostate cancer in a metastatic, non-symptomatic population of 30,000 men in the USA. Sipuleucel-T is prepared individually for each patient and infused in three sessions over a period of 1 month. However, in 2015, Dendreon, the owner of sipuleucel-T, filed for bankruptcy. This opinion paper reviews the probable reasons this innovative product failed to achieve commercial success. PubMed and internet searches were performed focused on pricing, reimbursement, and market access. We found that sipuleucel-T's FDA approval was delayed by 3 years, reportedly because of the vaccine's new mechanism of action. Sipuleucel-T was cleared by the European Medicines Agency 2 years later, but other national agencies were not approached. It was priced at $US93,000 for a course of treatment, and this high price combined with the company's late securement of reimbursement for the vaccine by the US Centers for Medicare and Medicaid Services (CMS) resulted in another year's delay in accessing the market. Despite a positive recommendation by the National Comprehensive Cancer Network, sipuleucel-T's complex administration, high price, and uncertainty about the reimbursement status deterred doctors from prescribing the product. Furthermore, the vaccine's supply was limited during the first year of launch due to limited manufacturing capacity. In addition, two oral metastatic prostate cancer drugs with similar survival benefits reached the US market 1 and 2 years after sipuleucel-T. Also, even though Dendreon's market capitalization topped $US7.5 billion following the FDA's approval of sipuleucel-T, this value degraded gradually until the firm's bankruptcy 5 years later. We conclude that the bankruptcy of Dendreon was largely due to the delay in securing FDA approval and CMS coverage, as well as the high cost that had to be incurred by providers up-front. Licensing sipuleucel-T to a pharmaceutical company more experienced in the market access pathway may have saved the company and the product.

Chemotherapy in frail elderly patients with hormone-refractory prostate cancer: A "real world" experience

BACKGROUND

In elderly patients affected by metastatic castration-resistant prostate cancer (mCRPC) chemotherapic treatment may be the choice if one considers not only the chronological age, but also the clinical status, the functional reserve, and the vulnerability of patients. Several studies have confirmed the survival benefit of docetaxel and vinorelbine among every class of age. Most CRP elderly patients are defined as frail, maybe due to comorbidities: these patients, who are unable to be candidates for a standard treatment, should be candidates for a more tolerable treatment.

METHODS

Twenty-six elderly, frail patients were evaluated. The patients were affected by mCRPC and were receiving chemotherapy with intravenous weekly docetaxel (12 patients) or oral metronomic vinorelbine (14 patients). Safety and efficacy were investigated evaluating clinical and objective response and tolerability. The level of patient satisfaction with treatment was assessed through a questionnaire.

RESULTS

No significant difference was found between groups in terms of 6-month progression-free survival: 57.1% for patients treated with oral metronomic vinorelbine versus 58.3% for patients treated with docetaxel. Median progression free survival was 8.6 months (95% confidence interval: 7.1-9.4 months), and 8.2 months (95% confidence interval: 6.9-9.3 months) for patients treated with oral metronomic vinorelbine and socetaxel, respectively. Oral metronomic vinorelbine was associated with increased patient satisfaction with respect to docetaxel administration. The most frequent side effect associated with oral metronomic vinorelbine was anemia and vomiting, with similar frequency compared to patients treated with docetaxel.

CONCLUSION

Weekly docetaxel and oral metronomic vinorelbine are equally effective and well tolerated in elderly unfit and frail patients affected by mCRPC. Metronomic vinorelbine treatment is associated with higher patient compliance and satisfaction.

Loss of signal transducer and activator of transcription 1 is associated with prostate cancer recurrence

STAT1 loss has previously been implicated in cell line studies to modify prostate cancer cell growth and survival, however the clinical significance of this has not previously been established. This study investigated if STAT1 loss was associated with patient outcome measures and the phenotypic consequence of STAT1 silencing. STAT1 expression was assessed in two patient cohorts with localised (n = 78) and advanced prostate cancer at initial diagnosis (n = 39) by immunohistochemistry (IHC). Impact of STAT1 silencing on prostate cancer cells lines was assessed using Cell Death detection ELISA, TLDA gene signature apoptosis arrays, WST-1 assay, xCELLigence system, clonogenic assay, and wound healing assay. In the localised patient cohort, low expression of STAT1 was associated with shorter time to disease recurrence (3.8 vs 7.3 years, P = 0.02) and disease specific survival (6.6 vs 9.3 years, P = 0.05). In the advanced patient cohort, low expression was associated with shorter time to disease recurrence (2.0 vs 3.9 years, P = 0.001). When STAT1 was silenced in PC3 cells (AR negative) and LNCaP cells (AR positive) silencing did not influence levels of apoptosis in either cell line and had little effect on cell viability in the LNCaP cells. In contrast, STAT1 silencing in the PC3 cells resulted in a pronounced increase in cell viability (WST-1 assay: mock silenced vs STAT1 silenced, P < 0.001), clonagenicity (clonogenic assay: mock silenced vs STAT1 silenced, P < 0.001), and migration (wound healing: mock silenced vs STAT1 silenced, P < 0.001). In conclusion, loss of STAT1 may promote prostate cancer recurrence in AR negative patients via increasing cell viability. © 2015 Wiley Periodicals, Inc.

Understanding the Racial and Ethnic Differences in Cost and Mortality Among Advanced Stage Prostate Cancer Patients (STROBE)

The aims of the study were to understand the racial/ethnic differences in cost of care and mortality in Medicare elderly with advanced stage prostate cancer.This retrospective, observational study used SEER-Medicare data. Cohort consisted of 10,509 men aged 66 or older and diagnosed with advanced-stage prostate cancer between 2001and 2004. The cohort was followed retrospectively up to 2009. Racial/ethnic variation in cost was analyzed using 2 part-models and quantile regression. Step-wise GLM log-link and Cox regression was used to study the association between race/ethnicity and cost and mortality. Propensity score approach was used to minimize selection bias.Pattern of cost and mortality varies between racial/ethnic groups. Compared with other racial/ethnic groups, non-Hispanic white patients had higher unadjusted costs in treatment and follow-up phases. Quintile regression results indicated that in treatment phase, Hispanics had higher costs in the 95th quantile and non-Hispanic blacks had lower cost in the 95th quantile, compared with non-Hispanic white men. In terminal phase non-Hispanic blacks and Hispanics had higher cost. After controlling for treatment, all-cause and prostate cancer-specific mortality was not significant for non-Hispanic black men, compared with non-Hispanic white men. However, for Asians, mortality remained significantly lower compared with non-Hispanic white men.In conclusion, relationship between race/ethnicity, cost of care, and mortality is intricate. For non-Hispanic black men, disparity in mortality can be attributed to treatment differences. To reduce racial/ethnic disparities in prostate cancer care and outcomes, tailored policies to address underuse, overuse, and misuse of treatment and health services are necessary.

Should docetaxel be standard of care for patients with metastatic hormone-sensitive prostate cancer? Pro and contra

Following the results of the TAX-327 study, questions have been raised as to whether administering chemotherapy to men with prostate cancer before symptomatic disease progression when receiving standard hormonal treatment can improve the duration and quality of patient survival. The GETUG-AFU-15 and CHAARTED studies both assessed the efficacy and tolerability of androgen deprivation therapy (ADT) with or without docetaxel in men with metastatic hormone-naive prostate cancer. Both studies included a mix of patients with de novo metastatic disease (∼75%) and patients who developed metastases following treatment of localized disease. A short course of ADT was allowed in both trials prior to accrual. Key differences between the two studies include the number of patients with high-volume metastases (GETUG-AFU-15: 52%; CHAARTED: 65%) and number of docetaxel cycles (GETUG-AFU-15: up to nine cycles; CHAARTED six cycles). Both studies reported an improvement in progression-free survival with docetaxel plus ADT versus ADT alone. The GETUG-AFU-15 did not find a significant difference in the primary end point of overall survival (OS) {hazard ratio (HR) 0.9 [95% confidence interval (CI) 0.7-1.2]; P = 0.44} for ADT plus docetaxel versus ADT alone. The CHAARTED study met the primary end point of OS [HR 0.61 (95% CI 0.47-0.80); P = 0.0003], and in a subset analysis reported the greatest improvement in OS for patients with high-volume disease [HR 0.60 (95% CI 0.45-0.81); P = 0.0006]. The following article debates the results from the GETUG-AFU-15 and CHAARTED studies and asks whether medical practice should be changed for patients with metastatic hormone-naive prostate cancer based on the results of one positive study.

Enzalutamide in European and North American men participating in the AFFIRM trial

Objective

To explore any differences in efficacy and safety outcomes between European (EU) (n = 684) and North American (NA) (n = 395) patients in the AFFIRM trial (NCT00974311).

Patients and Methods

Phase III, double-blind, placebo-controlled, multinational AFFIRM trial in men with metastatic castration-resistant prostate cancer (mCRPC) after docetaxel. Participants were randomly assigned in a 2:1 ratio to receive oral enzalutamide 160 mg/day or placebo. The primary end point was overall survival (OS) in a post hoc analysis.

Results

Enzalutamide significantly improved OS compared with placebo in both EU and NA patients. The median OS in EU patients was longer than NA patients in both treatment groups. However, the relative treatment effect, expressed as hazard ratio and 95% confidence interval, was similar in both regions: 0.64 (0.50, 0.82) for EU and 0.63 (0.47, 0.83) for NA. Significant improvements in other end points further confirmed the benefit of enzalutamide over placebo in patients from both regions. The tolerability profile of enzalutamide was comparable between EU and NA patients, with fatigue and nausea the most common adverse events. Four EU patients (4/461 enzalutamide-treated, 0.87%) and one NA patient (1/263 enzalutamide-treated, 0.38%) had seizures. The difference in median OS was related in part to the timing of development of mCRPC and baseline demographics on study entry.

Conclusion

This post hoc exploratory analysis of the AFFIRM trial showed a consistent OS benefit for enzalutamide in men with mCRPC who had previously progressed on docetaxel in both NA- and EU-treated patients, although the median OS was higher in EU relative to NA patients. Efficacy benefits were consistent across end points, with a comparable safety profile in both regions.

Implementing newer agents for the management of castrate-resistant prostate cancer: what is known and what is needed?

Men receiving androgen-deprivation therapy will in time develop metastatic castrate-resistant prostate cancer (mCRPC). Whilst effective treatment options for mCRPC have traditionally been limited, new agents are becoming available. Since 2010, the number and class of agents available to treat mCRPC has increased dramatically. As such, there is a need for clear guidance on the optimum treatment and sequence of treatments for mCRPC before and after chemotherapy. This evidence-based statement, reflecting the views of the authors, provides suggestions on the continued relevance of conventional approaches to first- and second-line treatment in mCRPC, the potential role of novel treatments, and factors that may influence the choice of hormonal agents and/or chemotherapy.

Perspectives on treatment of metastatic castration-resistant prostate cancer

The arrival of several new agents--cabazitaxel, abiraterone acetate, enzalutamide, and radium-223--is changing the treatment options and management of patients with metastatic castration-resistant prostate cancer (mCRPC). Many other novel agents are also being investigated. As new drugs become approved, new treatment strategies and markers to best select which patients will best respond to which drug are needed. This review article is a summary of a European Treatment Practices Meeting, which was convened to discuss these latest data on novel agents and current treatment strategies in the mCRPC setting.