The economics of abiraterone acetate for castration-resistant prostate cancer

Physiological roles of hydrogen sulfide in mammalian cells, tissues and organs

H2S belongs to the class of molecules known as gasotransmitters, which also includes nitric oxide (NO) and carbon monoxide (CO). Three enzymes are recognized as endogenous sources of H2S in various cells and tissues: cystathionine g-lyase (CSE), cystathionine β-synthase (CBS) and 3-mercaptopyruvate sulfurtransferase (3-MST). The current article reviews the regulation of these enzymes as well as the pathways of their enzymatic and non-enzymatic degradation and elimination. The multiple interactions of H2S with other labile endogenous molecules (e.g. NO) and reactive oxygen species are also outlined. The various biological targets and signaling pathways are discussed, with special reference to H2S and oxidative posttranscriptional modification of proteins, the effect of H2S on channels and intracellular second messenger pathways, the regulation of gene transcription and translation and the regulation of cellular bioenergetics and metabolism. The pharmacological and molecular tools currently available to study H2S physiology are also reviewed, including their utility and limitations. In subsequent sections, the role of H2S in the regulation of various physiological and cellular functions is reviewed. The physiological role of H2S in various cell types and organ systems are overviewed. Finally, the role of H2S in the regulation of various organ functions is discussed as well as the characteristic bell-shaped biphasic effects of H2S. In addition, key pathophysiological aspects, debated areas, and future research and translational areas are identified A wide array of significant roles of H2S in the physiological regulation of all organ functions emerges from this review.

A pharmacoeconomic evaluation of pharmaceutical treatment options for prostate cancer

INTRODUCTION

Prostate cancer is one of the most common neoplasms in men. For many years the mainstay of treatment was androgen deprivation therapy, but during last decade many novel agents have emerged, accompanied by increased costs for healthcare systems.

AREAS COVERED

In this literature review, the authors provide a pharmacoeconomic review of several pharmaceutical agents used in several disease stages, by summarizing evidence from cost-analysis, cost-effectiveness, cost-utility, cost-saving, cost-benefit and budgetary impact analysis studies.

EXPERT OPINION

The rapid development of therapeutic agents for prostate cancer has put a great budgetary burden on healthcare systems, since these drugs are prolonging survival and improving quality of life . Since existing data are now mature enough from a number of clinical trials with long-term follow-up, policy makers should propose not only the most clinically effective but also the most cost-effective agents, in order for every patient to gain access at least to some of these therapies. Docetaxel addition seems to be a cost-effective option, when compared to both abiraterone and enzalutamide (due to costs related to acquisition and side effects). Cabazitaxel is a strong candidate after docetaxel failure, while both denosumab and bisphosphonates are cost-effective for reducing skeletal-related events in metastatic disease.

An up-to-date evaluation of darolutamide for the treatment of prostate cancer

Introduction: Currently, in prostate cancer, an increasing number of novel drugs are being used to delay its advancement to metastatic castration-resistant prostate cancer (mCRPC). Apalutamide, enzalutamide, and most recently, darolutamide (novel androgen receptor antagonists) have been approved for nonmetastatic castration-resistant prostate cancer (nmCRPC).Areas covered: The authors have evaluated darolutamide, covering all aspects of the clinical development, competence, and safety profile of the drug.Expert opinion: The unique structure of darolutamide is characterized by a high affinity for androgen receptors and detainment of antagonist activity in mutant isoforms of androgen receptors. In clinical practice, this is the main reason that makes darolutamide exceptional in terms of safety and efficacy compared to other drugs in this category. Darolutamide is considered to have the lowest probability for adverse events (AEs) compared to apalutamide and enzalutamide. Future studies, along with real-world clinical data are warranted to improve personalized treatment strategies as well as sequencing treatment between approved novel drugs.

Pharmacotherapeutic strategies for castrate-resistant prostate cancer

INTRODUCTION

Metastatic castration-resistant prostate cancer (CRPC) is a potentially symptomatic disease with an eventual lethal outcome. Novel pharmaceutical agents are continuously studied with encouraging results in CRPC.

AREAS COVERED

In this perspective, the authors present established and promising pharmacotherapeutic strategies for the management of CRPC; both with and without metastases. Apart from the different treatment strategies, the authors present the relevant sequence of treatment through disease progression.

EXPERT OPINION

Usually, docetaxel should be considered the first line treatment in mCRPC. Abiraterone acetate (AA) plus prednisone or enzalutamide (ENZ) could be alternative treatments in chemotherapy naïve patients. Sipuleucel-T has been approved for the treatment of asymptomatic or minimally symptomatic mCRPC. Ra-223 has been approved for patients with mCRPC with symptomatic bone metastases (not visceral metastases). Cabazitaxel has been approved as the second line treatment to docetaxel in mCRPC. No differences in the overall survival has been observed between sequences starting with docetaxel versus AA/ENZ. Between AA-to-ENZ and ENZ-to-AA sequence, the AA-to-ENZ sequence appeared to be more favorable than the ENZ-to-AA regarding progression-free survival but not overall survival. Carbazitaxel seemed to retain its activity regardless of the treatment sequence. Of note, ENZ and apalutamide have been approved in non-metastatic CRPC.

Cost-effectiveness model of abiraterone plus prednisone, cabazitaxel plus prednisone and enzalutamide for visceral metastatic castration resistant prostate cancer therapy after docetaxel therapy resistance

Aims: Among patients diagnosed with prostate cancer, 10-20% will develop castration-resistant prostate cancer (CRPC) within 5 years; for 70%, CRPC will metastasize, mostly to the lungs and/or liver. We performed a cost-effectiveness model comparing abiraterone plus prednisone (ABI + PRD), cabazitaxel plus prednisone (CAB + PRD) and enzalutamide (ENZ) for visceral metastatic CRPC post-docetaxel therapy resistance. Methods: A three-state (Progression-Free, Progression, Death) lifetime Markov model was constructed to compare ABI + PRD, CAB + PRD, and ENZ from a United States healthcare payer perspective (2019 US$; discount rate 3%/yr.). Effectiveness was measured in life-years (LYs) and quality-adjusted life years (QALYs). Inputs included treatment costs, grade III/IV adverse events with incidence ≥5%, physician follow-up, lab and imaging tests. Phase III trial Kaplan-Meier curves were extrapolated to estimate overall survival and Progression-Free transition probabilities. Incremental cost-effectiveness ratios (ICERs) and utility ratios (ICURs), probabilistic sensitivity analyses (PSAs) and cost-effectiveness acceptability curves at willingness-to-pay (WTP) thresholds were estimated. Results: Models estimated 3-year overall survival rates of 1.3% for patients treated with ABI + PRD, 16.2% for CAB + PRD, and 13.2% for ENZ. Estimated Progression-Free rates at 1.5 years were 0.51% for ABI + PRD, 0.27% for CAB + PRD, and 14.47% for ENZ. LYs and QALYs were 1.20 and 0.58 respectively for ABI + PRD, 1.48 and 0.56 for CAB + PRD, and 1.58 and 0.79 for ENZ. Total treatment costs were: $115,433 for ABI + PRD, $85,337 for CAB + PRD and $109,213 for ENZ. CAB + PRD and ENZ dominated ABI + PRD due to higher LYs gained. Incremental QALYs for ENZ vs. CAB + PRD were larger than incremental LYs. The ICUR for ENZ was $103,674/QALY compared to CAB + PRD. Conclusions: This analysis found ENZ provided greater LYs and QALYs than both ABI + PRD and CAB + PRD, at a lower cost than ABI + PRD, but at a higher cost compared to CAB + PRD. For patients with visceral mCRPC after docetaxel therapy resistance, ENZ was cost-effective 92% of the time with a WTP threshold of $100,000/QALY.

Cost-effectiveness analyses and cost analyses in castration-resistant prostate cancer: A systematic review

Background

Treatment of metastatic prostate cancer is associated with high personal and economic burden. Recently, new treatment options for castration-resistant prostate cancer became available with promising survival advantages. However, cost-effectiveness of those new treatment options is sometimes ambiguous or given only under certain circumstances. The aim of this study was to systematically review studies on the cost-effectiveness of treatments and costs of castration-resistant prostate cancer (CRPC) and metastasizing castration-resistant prostate cancer (mCRPC) on their methodological quality and the risk of bias.

Methods

A systematic literature search was performed in the databases PubMed, CINAHL Complete, the Cochrane Library and Web of Science Core Collection for costs-effectiveness analyses, model-based economic evaluations, cost-of-illness analyses and budget impact analyses. Reported costs were inflated to 2015 US$ purchasing power parities. Quality assessment and risk of bias assessment was performed using the Consolidated Health Economic Evaluation Reporting Standards checklist and the Bias in Economic Evaluations checklist, respectively.

Results

In total, 38 articles were identified by the systematic literature search. The methodological quality of the included studies varied widely, and there was considerable risk of bias. The cost-effectiveness treatments for CRPC and mCRPC was assessed with incremental cost-effectiveness ratios ranging from dominance for mitoxantrone to $562,328 per quality-adjusted life year gained for sipuleucel-T compared with prednisone alone. Annual costs for the treatment of castration-resistant prostate cancer ranged from $3,067 to $77,725.

Conclusion

The cost-effectiveness of treatments of CRPC strongly depended on the willingness to pay per quality-adjusted life year gained/life-year saved throughout all included costs-effectiveness analyses and model-based economic evaluations. High-quality cost-effectiveness analyses based on randomized controlled trials are needed in order to make informed decisions on the management of castration-resistant prostate cancer and the resulting financial impact on the healthcare system.

Second-Line Hormonal Therapy for Men With Chemotherapy-Naïve, Castration-Resistant Prostate Cancer: American Society of Clinical Oncology Provisional Clinical Opinion

Purpose ASCO provisional clinical opinions (PCOs) offer direction to the ASCO membership after publication or presentation of potential practice-changing data. This PCO addresses second-line hormonal therapy for chemotherapy-naïve men with castration-resistant prostate cancer (CRPC) who range from being asymptomatic with only biochemical evidence of CRPC to having documented metastases but minimal symptoms. Clinical Context The treatment goal for CRPC is palliation. Despite resistance to initial androgen deprivation therapy, most men respond to second-line hormonal therapies. However, guidelines have neither addressed second-line hormonal therapy for nonmetastatic CRPC nor provided specific guidance with regard to the chemotherapy-naïve population. Recent Data Six phase III randomized controlled trials and expert consensus opinion inform this PCO. Provisional Clinical Opinion For men with CRPC, a castrate state should be maintained indefinitely. Second-line hormonal therapy (eg, antiandrogens, CYP17 inhibitors) may be considered in patients with nonmetastatic CRPC at high risk for metastatic disease (rapid prostate-specific antigen doubling time or velocity) but otherwise is not suggested. In patients with radiographic evidence of metastases and minimal symptoms, enzalutamide or abiraterone plus prednisone should be offered after discussion with patients about potential harms, benefits, costs, and patient preferences. Radium-223 and sipuleucel-T also are options. No evidence provides guidance about the optimal order of hormonal therapies for CRPC beyond second-line treatment. Prostate-specific antigen testing every 4 to 6 months is reasonable for men without metastases. Routine radiographic restaging generally is not suggested but can be considered for patients at risk for metastases or who exhibit symptoms or other evidence of progression. Additional information is available at www.asco.org/genitourinary-cancer-guidelines and www.asco.org/guidelineswiki .

Targeting the androgenic pathway in elderly patients with castration-resistant prostate cancer: A meta-analysis of randomized trials

BACKGROUND

The novel hormonal drugs have recently entered in the armamentarium of therapies for treatment of metastatic castration-resistant prostate cancer (CRPC). First reports are available for their use in elderly men with CRPC.

METHOD

A meta-analysis of randomized controlled trials (RCTs) has been performed. PubMed, the Cochrane Library, and American Society of Clinical Oncology (ASCO) University Meeting were searched for data on the use of new hormonal treatment in elderly patients with CRPC.

RESULTS

Nine studies for a total of 3512 elderly patients were available for meta-analysis. Six studies reported outcomes of patients aged >75 years old while 2 studies reported on patients aged >70 years old. The pooled analysis of the androgen synthesis inhibitors revealed significantly increased overall survival (OS) due to antiandrogen agents compared with placebo or placebo and prednisone (hazard ratio (HR) for death: HR = 0.74, 95% CI: 0.67-0.82; P < 0.00001). Moreover, the new antiandrogenic therapy significantly improved the progression-free survival (HR = 0.45, 95% CI: 0.31-0.65; P < 0.0001). The incidence of any grade ≥3 adverse effect was only moderately higher during with the antiandrogenic therapy as compared to the control arms (response rate = 1.03, 95% CI: 0.88-1.20; P = 0.72).

CONCLUSION

This study confirmed that agents targeting the androgen axis (i.e., enzalutamide, abiraterone) significantly prolonged OS in elderly men with CRPC.

Prognostic value of a computer-aided diagnosis system involving bone scans among men treated with docetaxel for metastatic castration-resistant prostate cancer

BACKGROUND

The bone scan index (BSI), which is obtained using a computer-aided bone scan evaluation system, is anticipated to become an objective and quantitative clinical tool for evaluating bone metastases in prostate cancer. Here, we assessed the usefulness of the BSI as a prognostic factor in patients with metastatic castration-resistant prostate cancer (mCRPC) treated using docetaxel.

METHODS

We analyzed 41 patients who received docetaxel for mCRPC. The Bonenavi system was used as the calculation program for the BSI. The utility of the BSI as a predictor of overall survival (OS) after docetaxel was evaluated. The Cox proportional hazards model was used to investigate the association between clinical variables obtained at docetaxel treatment, namely PSA, patient age, liver metastasis, local therapy, hemoglobin (Hb), lactase dehydrogenase (LDH), albumin (Alb), PSA doubling time, and BSI and OS.

RESULTS

The median OS after docetaxel therapy was 17.7 months. Death occurred in 22 (53.7%) patients; all deaths were caused by prostate cancer. In multivariate analysis, three factors were identified as significant independent prognostic biomarkers for OS after docetaxel; these were liver metastases (yes vs no; HR, 3.681; p = 0.026), Alb (<3.9 vs ≥ 3.9; HR, 3.776; p = 0.020), and BSI (>1% vs ≤ 1%; HR, 3.356; p = 0.037). We evaluated the discriminatory ability of our models including or excluding the BSI by quantifying the c-index. The BSI improved the c-index from 0.758 to 0.769 for OS after docetaxel. CRPC patients with a BSI >1 had a significantly shorter OS than patients with a BSI ≤ 1 (p = 0.029).

CONCLUSIONS

The BSI, liver metastases and Alb were independent prognostic factors for OS after docetaxel. The BSI might be a useful tool for risk stratification of mCRPC patients undergoing docetaxel treatment.

Is there still a place for docetaxel rechallenge in prostate cancer?

Three-weekly docetaxel plus prednisone is the standard first-line cytotoxic treatment for patients with metastatic castrate-resistant prostate cancer (mCRPC). Today, several new treatment options are available for patients with tumor progression after first-line docetaxel: Abiraterone, enzalutamide, cabazitaxel, sipuleucel-T immunotherapy, and the radionuclide radium-223. However, despite the evolving scenario in CRPC treatment, the optimal sequencing of the innovative therapies remains unclear. The reintroduction of docetaxel at the occurrence of disease progression after a drug holiday (docetaxel rechallenge) was often proposed, and this chemotherapeutic agent showed to maintain antitumor activity in mCRPC patients. Docetaxel rechallenge may still constitute a valid treatment option mainly for patients with favorable response to first-line docetaxel, at least > 3 mo progression-free interval, age less than 75 years, good performance status, and acceptable docetaxel toxicity. The risk of cumulative toxicity must be evaluated, since sensory neuropathy, nail disorders and fatigue might occur on docetaxel rechallenge.

Nomogram for overall survival of Japanese patients with bone-metastatic prostate cancer

BACKGROUND

We analyzed the relationship between prostate cancer outcomes and pretreatment clinical factors and developed a prognostic nomogram of overall survival (OS) of patients with bone metastasis.

METHODS

From 1993 to 2011, 463 consecutive patients were treated for bone-metastatic prostate cancer. Data sets from 361 patients were used to develop a nomogram (training data), and data sets of 102 patients were used for validation of the nomogram (validation data). Using the external validation data set, the nomogram was assessed for discriminatory ability, and the predictions were assessed for calibration accuracy by plotting actual survival against predicted risk.

RESULTS

Of the 361 patients in the training data set, 205 (56.8%) patients died, 169 (46.8%) deaths of which were due to prostate cancer. The median follow-up period was 55.2 months. In the multivariate analysis, patient age, serum prostate-specific antigen level, clinical T stage, extent of disease on bone scan, and biopsy Gleason sum were independent prognostic factors. We developed a prognostic model comprising these five factors for patients with bone-metastatic prostate cancer. This nomogram can be used to estimate 1-, 3-, and 5-year survival probability. External validation of this model using 102 validation data sets showed reasonable accuracy (concordance index, 0.719).

CONCLUSION

Our pretreatment prognostic nomogram might be useful for Japanese patients with bone-metastatic prostate cancer.

A review of rectal toxicity following permanent low dose-rate prostate brachytherapy and the potential value of biodegradable rectal spacers

Permanent radioactive seed implantation provides highly effective treatment for prostate cancer that typically includes multidisciplinary collaboration between urologists and radiation oncologists. Low dose-rate (LDR) prostate brachytherapy offers excellent tumor control rates and has equivalent rates of rectal toxicity when compared with external beam radiotherapy. Owing to its proximity to the anterior rectal wall, a small portion of the rectum is often exposed to high doses of ionizing radiation from this procedure. Although rare, some patients develop transfusion-dependent rectal bleeding, ulcers or fistulas. These complications occasionally require permanent colostomy and thus can significantly impact a patient's quality of life. Aside from proper technique, a promising strategy has emerged that can help avoid these complications. By injecting biodegradable materials behind Denonviller's fascia, brachytherpists can increase the distance between the rectum and the radioactive sources to significantly decrease the rectal dose. This review summarizes the progress in this area and its applicability for use in combination with permanent LDR brachytherapy.