Effect of abiraterone acetate on fatigue in patients with metastatic castration-resistant prostate cancer after docetaxel chemotherapy

Assessment and Management of Cognitive Function in Patients with Prostate Cancer Treated with Second-Generation Androgen Receptor Pathway Inhibitors

Preservation of cognitive function is an important outcome in oncology. Optimal patient management requires an understanding of cognitive effects of the disease and its treatment and an efficacious approach to assessment and management of cognitive dysfunction, including selection of treatments to minimize the risk of cognitive impairment. Awareness is increasing of the potentially detrimental effects of cancer-related cognitive dysfunction on functional independence and quality of life. Prostate cancer occurs most often in older men, who are more likely to develop cognitive dysfunction than younger individuals; this population may be particularly vulnerable to treatment-related cognitive disorders. Prompt identification of treatment-induced cognitive dysfunction is a crucial aspect of effective cancer management. We review the potential etiologies of cognitive decline in patients with prostate cancer, including the potential role of androgen receptor pathway inhibitors; commonly used tools for assessing cognitive function validated in metastatic castration-resistant prostate cancer and adopted in non-metastatic castration-resistant prostate cancer trials; and strategies for management of cognitive symptoms. Many methods are currently used to assess cognitive function. The prevalence and severity of cognitive dysfunction vary according to the instruments and criteria applied. Consensus on the definition of cognitive dysfunction and on the most appropriate approaches to quantify its extent and progression in patients treated for prostate cancer is lacking. Evidence-based guidance on the appropriate tools and time to assess cognitive function in patients with prostate cancer is required.

Impact of fatigue on quality of life among breast cancer patients receiving chemotherapy

Objectives

Fatigue is the most frequently reported symptom experienced by cancer patients and has a profound effect on their quality of life (QOL). The study aimed to determine the impact of fatigue on QOL among breast cancer patients receiving chemotherapy and to identify the risk factors associated with severe fatigue incidence.

Methods

This was an observational prospective study carried out at multiple centers. In total, 172 breast cancer patients were included. The Functional Assessment of Chronic Illness Therapy-Fatigue Questionnaire was used to measure QOL, while the Brief Fatigue Inventory (BFI) was used to assess the severity of fatigue.

Results

The total average mean and standard deviation of QOL were 84.58±18.07 and 4.65±1.14 for BFI scores, respectively. A significant association between fatigue and QOL was found in linear and multiple regression analyses. The relationships between fatigue severity and cancer stage, chemotherapy dose delay, dose reduction, chemotherapy regimen, and ethnicity were determined using binary logistic regression analysis.

Conclusion

The findings of this study are believed to be useful for helping oncologists effectively evaluate, monitor, and treat fatigue related to QOL changes.

Health-Related Quality-of-Life Outcomes with Actinium-225-Prostate-Specific Membrane Antigen-617 Therapy in Patients with Heavily Pretreated Metastatic Castration-Resistant Prostate Cancer

Aims

Actinium-225 (²²⁵Ac) labeled prostate-specific membrane antigen (PSMA)-617 is a novel treatment modality in the management of metastatic castration-resistant prostate cancer (mCRPC). The present study was conducted to assess the impact of ²²⁵Ac-PSMA-617 therapy on the quality-of-life of patients with heavily pretreated mCRPC using the National Comprehensive Cancer Network-Functional Assessment of Cancer Therapy-Prostate Symptom Index-17 (NCCN-FACT-FPSI-17) questionnaire.

Materials and Methods

This was a retrospective single-center study where data of consecutive heavily pretreated mCRPC patients treated with ²²⁵Ac-PSMA-617 from January 2019 to February 2020, was collected and analyzed for the biochemical response, quality-of-life outcomes and treatment-related toxicity.

Results

Eleven heavily pretreated mCRPC patients received a median cumulative dose of 8.3 MBq (interquartile range [IQR] 5.6-20.4 MBq) ²²⁵Ac-PSMA-617 over 1-4 cycles. 5/11 patients (46%) showed a ≥50% decline in Prostate Specific Antigen (PSA), while stable values and PSA progression were observed in 3/11 (27%) patients each. Pre- and post-therapy NCCN-FACT-FPSI-17 questionnaires revealed statistically significant improvement in the total FPSI score (P = 0.003) as well as the disease-related symptoms-physical (P = 0.004) and disease-related symptoms-emotional (P = 0.046) subscores. Among the physical symptoms, significant improvement was noted with respect to pain, difficulty in urination, bone pain, fatigue, and restriction in physical activity. No significant change was noted in the treatment side-effects subscore. Of the treatment-related adverse effects, Grade 3 dryness of the mouth, anemia, and nephrotoxicity was observed in 1/11 patients (9%) each and Grade 3 thrombocytopenia in 2/11 patients (18%).

Conclusion

Health-related quality-of-life of the mCRPC patients improved significantly with ²²⁵Ac-PSMA-617 despite extensive pretreatment and advanced nature of the disease.

Darolutamide: An Evidenced-Based Review of Its Efficacy and Safety in the Treatment of Prostate Cancer

Men treated with androgen deprivation therapy for rising PSA after failed local therapy will often develop castrate resistance, and the appearance of metastases predicts a poor prognosis. Thus, researchers have long sought to prolong the onset of metastasis in patients with nonmetastatic castration-resistant prostate cancer (CRPC). Until 2018, patients in this group had no FDA-approved treatment options. They were typically managed with androgen-deprivation therapy (ADT) to maintain castrate systemic testosterone levels and given approved therapies for metastatic CRPC once metastases appeared. However, third-generation androgen receptor inhibitors (ARIs) have dramatically changed the treatment paradigm, having shown the ability to extend metastasis-free survival (MFS) significantly over ADT alone in Phase 3 trials. The newest of these, darolutamide, prolonged MFS 22 months over placebo while also improving a host of secondary and exploratory endpoints such as overall survival (OS), prostate-specific antigen (PSA) progression and time to pain progression, chemotherapy initiation, and symptomatic skeletal events. Among third-generation ARIs, darolutamide is unique in that it incorporates two pharmacologically active diastereomers and has demonstrated resistance to all known androgen receptor (AR) mutations. Additionally, patients taking darolutamide appear to experience comparatively few central nervous system-related adverse events (AEs) such as fatigue and falls, and no increases in seizures have been reported in the drug's clinical or preclinical development. Various authors attribute the low incidence of CNS-related AEs to darolutamide's minimal penetration of the blood-brain barrier (BBB). Other side effects ranging from hot flashes to hypothyroidism also occurred at rates similar to those of the placebo arm in Phase 3. As ADT in itself raises cardiovascular risk, the cardiovascular safety of third-generation antiandrogens as a category warrants continued scrutiny. In total, however, published data suggest that darolutamide provides a reasonable option for patients with nonmetastatic CRPC. Ongoing research will determine darolutamide's potential role in additional disease states such as localized and castration-sensitive PCa.

Abiraterone acetate in combination with prednisone in the treatment of prostate cancer: safety and efficacy

INTRODUCTION

Metastatic prostate cancer is a life-threatening disease and an important public health concern with prevalence rates varying drastically between high- and low-income countries. Androgen-deprivation therapy alone has been the first-line treatment option for decades, temporarily controlling disease until invariable tumor regression. At the castration-resistant stage, metastatic disease becomes lethal. In recent years several new treatments, including second-generation hormone therapies, have proven to be life-prolonging in metastatic castration-resistant prostate cancer, and at an earlier hormone-sensitive stage. Abiraterone acetate in combination with prednisone was the first approved hormone therapy demonstrating survival benefit, and represents, to date, an alternative, or a second-line treatment after taxane-based chemotherapy, in addition to androgen-deprivation therapy, in hormone sensitive, and metastatic castration-resistant prostate cancer.

AREA COVERED

We performed a literature review of papers from 2012 to 2020 using PubMed, Web of Science, and Embase searching for the safety and efficacy of abiraterone acetate in prostate cancer management. Search results were limited to phase III-IV trials and post hoc analysis of Phase III trials evaluated Abiraterone acetate in the English language.

EXPERT OPINION

This literature review confirms the role of abiraterone acetate in the therapeutic landscape with well-proven safety and efficacy, demonstrated in trials and post-approval studies.

Comparing the clinical efficacy and safety of abiraterone and enzalutamide in metastatic castration-resistant prostate cancer: A systematic review and meta-analysis

BACKGROUND

Two new drugs, abiraterone and enzalutamide, had recently shown beneficial effects on survival in patients with metastatic castration-resistant prostate cancer. We systematically reviewed the efficacy and safety of abiraterone and enzalutamide in metastatic castration-resistant prostate cancer in real-world practice.

METHODS

A search from PubMed, Web of Science, Cochrane, Embase was conducted up to 6 March 2019. Available articles from conferences were searched. The endpoint was prostate-specific antigen response, overall survival, progression-free survival, number of patients with any adverse event.

RESULTS

Fourteen cohort studies involving 3469 participants were included. Pooled result showed that prostate-specific antigen response was higher for patients receiving enzalutamide than abiraterone (790 patients, odds ratio (OR) 0.47, 95% confidence interval (CI) 0.29-0.77, P = 0.003, I²=59%). Enzalutamide was significantly associated with increased adverse events rate in comparison with abiraterone (730 patients, OR 0.35, 95%CI 0.13-0.92, P = 0.03, I²=65%). There was no statistical difference between abiraterone and enzalutamide with respect to perceived cognitive impairments (1856 patients, OR 0.90, 95%CI 0.29-2.76, P = 0.85, I²=5%). Enzalutamide was significantly associated with increased fatigue risk in comparison with abiraterone (2477 patients, OR 0.46, 95%CI 0.34-0.63, P＜0.00001, I²=0%).

CONCLUSIONS

Our results demonstrated that enzalutamide was more efficacious than abiraterone for patients with metastatic castration-resistant prostate cancer, but was associated with a significantly elevated risk of side effects, particularly fatigue.

Are the MORECare guidelines on reporting of attrition in palliative care research populations appropriate? A systematic review and meta-analysis of randomised controlled trials

BACKGROUND

Palliative care trials have higher rates of attrition. The MORECare guidance recommends applying classifications of attrition to report attrition to help interpret trial results. The guidance separates attrition into three categories: attrition due to death, illness or at random. The aim of our study is to apply the MORECare classifications on reported attrition rates in trials.

METHODS

A systematic review was conducted and attrition classifications retrospectively applied. Four databases, EMBASE; Medline, CINHAL and PsychINFO, were searched for randomised controlled trials of palliative care populations from 01.01.2010 to 08.10.2016. This systematic review is part of a larger review looking at recruitment to randomised controlled trials in palliative care, from January 1990 to early October 2016. We ran random-effect models with and without moderators and descriptive statistics to calculate rates of missing data.

RESULTS

One hundred nineteen trials showed a total attrition of 29% (95% CI 28 to 30%). We applied the MORECare classifications of attrition to the 91 papers that contained sufficient information. The main reason for attrition was attrition due to death with a weighted mean of 31.6% (SD 27.4) of attrition cases. Attrition due to illness was cited as the reason for 17.6% (SD 24.5) of participants. In 50.8% (SD 26.5) of cases, the attrition was at random. We did not observe significant differences in missing data between total attrition in non-cancer patients (26%; 95% CI 18-34%) and cancer patients (24%; 95% CI 20-29%). There was significantly more missing data in outpatients (29%; 95% CI 22-36%) than inpatients (16%; 95% CI 10-23%). We noted increased attrition in trials with longer durations.

CONCLUSION

Reporting the cause of attrition is useful in helping to understand trial results. Prospective reporting using the MORECare classifications should improve our understanding of future trials.

PREVALENCE OF FATIGUE AND IMPACT ON QUALITY OF LIFE IN CASTRATION-RESISTANT PROSTATE CANCER PATIENTS: the VITAL study

Background

Fatigue is one of the most prevalent symptoms among cancer patients. Specifically, in metastatic castration-resistant prostate cancer (mCRPC) patients, fatigue is the most common adverse event associated with current treatments. The purpose of this study is to describe the prevalence of fatigue and its impact on quality of life (QoL) in patients with CRPC in routine clinical practice.

Methods

This was a cross-sectional, multicentre study. Male chemo-naïve adults with high-risk non-metastatic (M0) CRPC and metastatic (M1) CRPC (mCRPC) were eligible. Fatigue was measured using the Brief Fatigue Inventory (BFI) and QoL was assessed using the Functional Assessment of Cancer Therapy questionnaire for patients with prostate cancer (FACT-P) and the FACT-General (FACT-G) questionnaire. Data were analysed using Mann-Whitney or Kruskal-Wallis tests (non-parametric distribution), a T-test or an ANOVA (parametric distribution) and the Fisher or chi-squared tests (categorical variables).

Results

A total of 235 eligible patients were included in the study (74 [31.5%] with M0; and 161 [68.5%] with M1). Fatigue was present in 74%, with 38.5% of patients reporting moderate-to-severe fatigue. Mean FACT-G and FACT-P overall scores were 77.6 ± 16.3 and 108.7 ± 21.4, respectively, with no differences between the CRPC M0 and CRPC M1 subgroups. Fatigue intensity was associated with decreased FACT-G/P scores, with no differences between groups. Among 151 mCRPC patients with available treatment data, those treated with abiraterone-prednisone ≥3 months showed a significant reduction in fatigue intensity (p = 0.043) and interference (p = 0.04) compared to those on traditional hormone therapy (HT). Patients on abiraterone-prednisone ≥3 months showed significantly better FACT-G/P scores than patients on HT (p = 0.046 and 0.018, respectively).

Conclusion

Our data show a high prevalence and intensity of fatigue and its impact on QoL in chemo-naïve CRPC patients. There is an association between greater fatigue and less QoL, irrespective of the presence or absence of metastasis. Chemo-naïve mCRPC patients receiving more than 3 months of abiraterone acetate plus prednisone showed an improvement of fatigue and QoL when compared to those on traditional HT.

Trial registration

Not applicable since it is not an interventional study.

Cross-sectional study of patient-reported fatigue, physical activity and cardiovascular status in men after robotic-assisted radical prostatectomy

Purpose

Patient-reported fatigue after robotic-assisted radical prostatectomy (RARP) has not been characterised to date. Fatigue after other prostate cancer (PCa) treatments is known to impact on patient-reported quality of life. The aim of this study was to characterise fatigue, physical activity levels and cardiovascular status post-RARP.

Methods

Between October 2016 and March 2017, men post-RARP or on androgen deprivation therapy (ADT) were invited into the study. Participants were asked to complete the Brief Fatigue Inventory (BFI) and Stage of Change and Scottish Physical Activity Questionnaires (SPAQ) over a 2-week period. Outcome measures were patient-reported fatigue, physical activity levels and the 10-year risk of cardiovascular disease (Q-Risk). Data were analysed in SPSS.

Results

96/117 (82%) men approached consented to participate; of these, 62/96 (65%) returned complete questionnaire data (RARP n = 42, ADT n = 20). All men reported fatigue with 9/42 (21%) post-RARP reporting clinically significant fatigue. Physical activity did not correlate with fatigue. On average, both groups were overweight (BMI 27.0 ± 3.9 kg/m² and 27.8 ± 12.3 kg/m² for RARP and ADT, respectively) and the post-RARP group had an 18.1% ± 7.4% Q-Risk2 score.

Conclusions

A proportion of men is at increased risk of cardiovascular disease within 10 years post-RARP and have substantial levels of fatigue; therefore, clinicians should consider including these factors when counselling patients about RARP. Additionally, men post-RARP did not meet the recommended guidelines for resistance-based exercise. Future research is needed to establish whether interventions including resistance-based exercise can improve health and fatigue levels in this population.

Abiraterone Acetate: A Review in Metastatic Castration-Resistant Prostrate Cancer

Oral abiraterone acetate (Zytiga^®) is a selective inhibitor of CYP17 and thereby inhibits androgen biosynthesis, with androgen signalling crucial in the progression from primary to metastatic prostate cancer (PC) and subsequently, in the development of metastatic castration-resistant PC (mCRPC). In large phase 3 trials and in the clinical practice setting, oral abiraterone acetate in combination with prednisone was an effective treatment and had an acceptable, manageable tolerability and safety profile in chemotherapy-naive and docetaxel-experienced men with mCRPC. In the pivotal global phase 3 trials, relative to placebo (+prednisone), abiraterone acetate (+prednisone) prolonged overall survival (OS) at data maturity (final analysis) and radiographic progression-free survival (rPFS) at all assessed timepoints. Given its efficacy in prolonging OS and its convenient once-daily oral regimen, in combination with prednisone, abiraterone acetate is an important first-line option for the treatment of mCRPC.

Quality of life in pre- and postmenopausal patients with early breast cancer: a comprehensive analysis from the prospective MaLife project

Purpose

Quality of life (QoL) plays an important role in recovery—especially after an incisive diagnosis such as breast cancer. Here, we present a comprehensive assessment of QoL for pre- and postmenopausal patients, starting from initial systemic treatment of early breast cancer until 3 years later, in patients from a so-called “real-world” setting.

Methods

251 premenopausal and 478 postmenopausal patients with early breast cancer have been recruited into the longitudinal MaLife project within the prospective, multicentre, German Tumour Registry Breast Cancer between 2011 and 2015. The questionnaires FACT-G, FACT-Taxane, FACT-ES, EORTC QLQ-BR23, BFI and HADS were filled in at start of treatment (T0), 6, 12, 24 and 36 months later. The proportion of patients with clinically meaningful changes at 36 months was determined.

Results

This first interim analysis shows that the FACT-G global QoL improved over time regardless of the menopausal status. However, clinically meaningful decrease of social/family well-being (48–51%), arm symptoms (44–49%) and symptoms of neurotoxicity (55–56%) was frequently reported 3 years after start of treatment. Many premenopausal patients also reported a clinically meaningful worsening of endocrine symptoms (64%), emotional well-being (36%) and fatigue intensity (37%). Additionally, 3 years after start of treatment, 15% of the patients were classified as doubtful cases and 18% as definite cases of anxiety.

Conclusions

Despite improvements in global QoL, breast cancer survivors report worsened ailments 3 years after start of therapy. Follow-up care should distinguish between premenopausal patients needing special attention for emotional/menopausal issues, and postmenopausal patients needing particular care regarding physical concerns.

Electronic supplementary material

The online version of this article (10.1007/s10549-019-05197-whttps://doi.org/10.1007/s10549-019-05197-w) contains supplementary material, which is available to authorized users.

Clinical Development of Darolutamide: A Novel Androgen Receptor Antagonist for the Treatment of Prostate Cancer

Prostate cancer (PC) is the second most common cancer in men and is the fifth leading cause of cancer-related deaths among men. Androgen receptor (AR) signaling plays a key role in PC tumor growth and progression, with androgens stimulating PC proliferation and survival. Castration-resistant PC (CRPC) is characterized by increasing levels of prostate-specific antigen or radiographic progression despite androgen-deprivation therapy (ADT). In most patients, castration resistance results from aberrations in AR or the AR signaling pathway. Up to one-third of patients with localized high-risk PC will have disease progression on local therapy and develop CRPC. This review summarizes the key clinical data, including ongoing trials, for hormonal therapies in CRPC and provides an overview of the clinical development of darolutamide, a novel, nonsteroidal AR antagonist currently in phase III development for the treatment of nonmetastatic CRPC and metastatic hormone-sensitive PC. In phase I/II trials, darolutamide has demonstrated a favorable safety profile, antitumor activity, and significant decreases in prostate-specific antigen in patients with metastatic CRPC. In the phase III ARAMIS (NCT02200614; A Multinational, Randomized, Double-Blind, Placebo-Controlled, Phase III Efficacy and Safety Study of Darolutamide [ODM-201] in Men With High-Risk Non-metastatic Castration-Resistant Prostate Cancer) study, metastasis-free survival is being evaluated in men with nonmetastatic CRPC who will receive ADT in combination with darolutamide or placebo. The ARASENS (NCT02799602; A Randomized, Double-Blind, Placebo Controlled Phase III Study of Darolutamide [ODM-201] Versus Placebo in Addition to Standard Androgen Deprivation Therapy and Docetaxel in Patients With Metastatic Hormone Sensitive Prostate Cancer) study is a placebo-controlled trial assessing whether the addition of darolutamide to ADT and docetaxel significantly prolongs overall survival in men with metastatic hormone-sensitive PC.

Abiraterone acetate and its use in the treatment of metastatic prostate cancer: a review

Abiraterone acetate, which targets enzymatic complexes playing a central role in steroidogenesis, demonstrated to increase survival significantly in both chemo-naive and docetaxel pretreated, becoming one of the drugs of choice for metastatic castration-resistant prostate cancer. More recently, this agent in combination to androgen deprivation therapy demonstrated to be efficacious also in metastatic castration-sensitive prostate cancer. The present review is aimed to outline the clinical development of abiraterone acetate, the pivotal trials which led to its approval for the clinical practice, new evidence about its efficacy in metastatic castration-sensitive prostate cancer, its place in the therapeutic landscape of prostate cancer and future directions of development.

Efficacy and safety of post-docetaxel therapies in metastatic castration-resistant prostate cancer: a systematic review of the literature

OBJECTIVE

Prostate cancer is a highly prevalent form of cancer in older men and is one of the leading causes of death from cancer in men across the globe. Many therapeutic agents have been approved for patients with metastatic castration-resistant prostate cancer (mCRPC), particularly as a post-docetaxel treatment strategy. The objective of this systematic literature review was to assess published efficacy and safety data for select mCRPC therapies - such as abiraterone, cabazitaxel, and enzalutamide - in the post-docetaxel setting.

METHODS

Database searches of MEDLINE, Embase, and Cochrane CENTRAL, in conjunction with hand searches of multiple congress abstracts, yielded 13 randomized studies and 107 non-randomized studies that met the inclusion criteria.

RESULTS

Randomized studies demonstrated significant improvements in median overall survival (OS) outcomes over placebo for abiraterone (15.8 vs. 11.2 months) and enzalutamide (18.4 vs. 13.6 months), and similar significant improvements were noted for cabazitaxel over mitoxantrone (15.1 vs. 12.7 months). Differences in progression-free survival (PFS) were similarly significant, although variance in the criteria for measuring PFS may limit the extent to which these outcomes can be compared between studies. Non-randomized evidence included multiple publications from several early access and compassionate use programs with a primary objective to report safety outcomes. Results from these studies largely reflected the findings in randomized trials.

CONCLUSIONS

Overall, there is a growing body of evidence for post-docetaxel treatment options available in patients with mCRPC. Further head-to-head trials or indirect treatment comparisons may be a valuable method to assess the comparative efficacy of these therapies.

Quality of Life in Second-Line Treatment of Metastatic Castration-Resistant Prostate Cancer Using Cabazitaxel or Other Therapies After Previous Docetaxel Chemotherapy: Swiss Observational Treatment Registry

BACKGROUND

The aim was to evaluate quality of life (QoL), pain, and fatigue in patients with metastatic castration-resistant prostate cancer (mCRPC) treated with different regimens after first-line docetaxel, as well as disease progression.

PATIENTS AND METHODS

Patients with mCRPC having received first-line chemotherapy with docetaxel were eligible. Second-line treatment choice was at the discretion of the local investigator. All patients had regular assessments of QoL with the Functional Assessment of Cancer Therapy-Prostate (FACT-P) questionnaire, of fatigue with the Brief Fatigue Inventory, and of pain with the McGill Pain Questionnaire-Short Form. The primary end point was QoL maintenance defined as having a maximum decrease in 2 functional domains of the FACT-P.

RESULTS

One hundred thirty-eight patients were included in 36 oncology centers across Switzerland. QoL analysis was available for all patients (59 who received cabazitaxel; 79 who received other therapy [OT] including 75 who received abiraterone). No significant differences for any of the end points were found between groups. A numerically higher number of patients had QoL maintenance with OT (25 of 79 patients, 32%) compared with cabazitaxel (8 of 59 patients, 14%). QoL improvement was found in 20% of patients (12 of 59) who received cabazitaxel and 24% (19 of 79) who received OT. Mean FACT-P score did not change in a clinically relevant manner over time in either group. Pain was present in 70% of patients (96 of 138), and a pain response to treatment was noted in 22% (13 of 59) who received cabazitaxel and 29% (23 of 79) who received OT. A similar but minor improvement of fatigue was noted in both groups.

CONCLUSION

Some degree of QoL decrease was seen in most patients regardless of second-line treatment. No significant differences in QoL parameters between cabazitaxel or other second line treatments were found.

Impact of abiraterone on patient-related outcomes in metastatic castration-resistant prostate cancer: current perspectives

Abiraterone acetate has established a major role in the treatment paradigm of metastatic castration-resistant prostate cancer ever since pivotal trials, COU-AA-301 and COU-AA-302, have shown benefit in both the second-line and first-line (post- and pre-chemotherapy) setting, respectively, with improvement in overall survival as well as secondary end points such as prostate-specific antigen (PSA) and radiographic response rates, time to PSA progression, and progression-free survival. There has been a lot of interest and emphasis in the evaluation of patient-related outcomes (PROs) as it relates to quality of life, pain, adverse events, fatigue, and among others, in the use of different agents that have been shown to improve survival. This review examines the companion PROs in conjunction with abiraterone acetate use. This is particularly relevant since PROs are increasingly viewed as a key metric for drug label claims in granting approval across regulatory agencies, including the US Food and Drug Administration and the European Medicines Agency.

Duration of Treatment in Prostate Cancer Patients Treated with Abiraterone Acetate or Enzalutamide

BACKGROUND

Abiraterone acetate (AA) and enzalutamide (ENZ) are oral therapies offering survival benefit to metastatic castration-resistant prostate cancer (mCRPC) patients. Despite the availability of multiple treatment options for mCRPC, there is a lack of information on the effect that being initiated on AA or ENZ has on the combined prostate cancer treatment duration.

OBJECTIVE

To compare the combined duration of prostate cancer treatments of patients initiated on AA with that of patients initiated on ENZ.

METHODS

Truven Health MarketScan Research Databases from March 2012 to December 2014 were used to identify males with prostate cancer initiated on AA or ENZ (index therapy). Baseline characteristics were assessed during the 6 months pre-index. Inverse probability of treatment weights (IPTWs) were used to reduce baseline confounding. Treatment duration spanned from the index date to the earliest of treatment discontinuation (defined as a > 60-day gap in treatment), 24 months post-index, health plan disenrollment, or end of data. Weighted Kaplan-Meier and Cox proportional hazard models were used to compare the combined duration of mCRPC treatments (AA, ENZ, chemotherapy, sipuleucel-T, and radium 223) and any prostate cancer treatments (mCRPC, hormonal, and corticosteroid treatments) between patients initiated on either AA or ENZ.

RESULTS

A total of 2,591 patients initiated on AA and 807 patients initiated on ENZ were selected for the study. Patients' characteristics were generally well balanced after IPTW. At 3 months, patients initiated on AA were associated with fewer discontinuations of mCRPC treatments (hazard ratio [HR] = 0.73, P = 0.004) or of any prostate cancer treatments (HR = 0.61, P = 0.002), compared with patients initiated on ENZ. This result was maintained at 6, 9, 12, 18, and 24 months for mCRPC treatments (HR = 0.75, P < 0.001) and for any prostate cancer treatments (HR = 0.69, P < 0.001). Median duration of mCRPC treatments was 4.1 months longer for patients initiated on AA compared with those initiated on ENZ (18.3 vs. 14.2 months, P < 0.001) and similarly, the median duration of any prostate cancer treatment was longer for patients initiated on AA compared with those initiated on ENZ (not reached vs. 22.2 months, P < 0.001).

CONCLUSIONS

In this study, patients initiated on AA, compared with those initiated on ENZ, had a longer combined duration of mCRPC or prostate cancer treatments.

DISCLOSURES

This research was funded by Janssen Scientific Affairs. Pilon, Emond, and Lefebvre are employees of Analysis Group, a consulting company that has received research grants from Janssen Scientific Affairs. Behl and Ellis are employees of Janssen Scientific Affairs and stockholders in Johnson & Johnson. Dawson is on the speakers bureau for Janssen, Astellas, and Sanofi Aventis. Emond reports grants from Regeneron, Bristol-Myers Squibb, GlaxoSmithKline, Aegerion, Bayer, Novartis, Allergan, Millenium, and Genentech. Pilon reports grants from Novartis, GlaxoSmithKline, Pfizer, and Bayer. Lefebvre reports grants from GlaxoSmithKline, Novartis, Bayer, Medtronic, Noven, and Novo Nordisk. Study concept and design were contributed primarily by Pilon and Lefebvre, along with the other authors. Pilon, Emond, and Lefebre collected the data, and data interpretation was performed by Behl, Lefebvre, and Dawson, along with Pilon, Ellis, and Emond, The manuscript was written by Pilon, Emond, and Lefebvre and revised by Behl, Ellis, and Dawson.

Patient-reported outcomes in metastatic castration-resistant prostate cancer

Many novel therapies are available for use in patients with metastatic castration-resistant prostate cancer (mCRPC), some of which convey substantial progression-free survival and overall survival benefits. Delaying disease progression and providing palliation of symptoms are primary therapeutic aims of treating patients with mCRPC; therefore, ensuring that the benefit-to-harm ratios are acceptable to patients, through systematic measurement of patient-reported outcomes (PROs) using validated tools, is vital. In this Perspectives, we appraised the published reports from clinical trials testing treatments of mCRPC over the past 5 years and found that PROs were either not being measured routinely, or if used, were often not reported adequately, thus hampering evaluation of the true effects of many of these treatments on patients' quality of life. Improvements are needed because data collected directly from patients, not just physician-collected safety data and adverse events, are crucial to inform clinical decision-making on treatment options.

Patient-reported quality-of-life analysis of radium-223 dichloride from the phase III ALSYMPCA study

BACKGROUND

Radium-223 dichloride (radium-223), a first-in-class α-emitting radiopharmaceutical, is recommended in both pre- and post-docetaxel settings in patients with castration-resistant prostate cancer (CRPC) and symptomatic bone metastases based on overall survival benefit demonstrated in the phase III ALSYMPCA study. ALSYMPCA included prospective measurements of health-related quality of life (QOL) using two validated instruments: the general EuroQoL 5D (EQ-5D) and the disease-specific Functional Assessment of Cancer Therapy-Prostate (FACT-P).

PATIENTS AND METHODS

Analyses were conducted to determine treatment effects of radium-223 plus standard of care (SOC) versus placebo plus SOC on QOL using FACT-P and EQ-5D. Outcomes assessed were percentage of patients experiencing improvement, percentage of patients experiencing worsening, and mean QOL scores during the study.

RESULTS

Analyses were carried out on the intent-to-treat population of patients randomized to receive radium-223 (n = 614) or placebo (n = 307). The mean baseline EQ-5D utility and FACT-P total scores were similar between treatment groups. A significantly higher percentage of patients receiving radium-223 experienced meaningful improvement in EQ-5D utility score on treatment versus placebo {29.2% versus 18.5%, respectively; P = 0.004; odds ratio (OR) = 1.82 [95% confidence interval (CI) 1.21-2.74]}. Findings were similar for FACT-P total score [24.6% versus 16.1%, respectively; P = 0.020; OR = 1.70 (95% CI 1.08-2.65)]. A lower percentage of patients receiving radium-223 experienced meaningful worsening versus placebo measured by EQ-5D utility score and FACT-P total score. Prior docetaxel use and current bisphosphonate use did not affect these findings. Treatment was a significant predictor of EQ-5D utility score, with radium-223 associated with higher scores versus placebo (0.56 versus 0.50, respectively; P = 0.002). Findings were similar for FACT-P total score (99.08 versus 95.22, respectively; P = 0.004).

CONCLUSIONS

QOL data from ALSYMPCA demonstrated that improved survival with radium-223 is accompanied by significant QOL benefits, including a higher percentage of patients with meaningful QOL improvement and a slower decline in QOL over time in patients with CRPC.

Low-dose docetaxel, estramustine and prednisolone combination chemotherapy for castration-resistant prostate cancer

The objective of this study was to report our experience with weekly low-dose docetaxel (DOC) chemotherapy for patients with castration-resistant prostate cancer (CRPC). From 2007 to 2014, 39 consecutive patients received weekly low-dose DOC; the oncological effectiveness, side effects and tolerability were prospectively analyzed. The median patient age, serum prostate-specific antigen (PSA) level and Gleason score at diagnosis of prostate cancer were 71 years (range, 55-83 years), 187 ng/ml (range, 2.0-1711 ng/ml) and 8 (range, 5-10), respectively. The median number of cycles of DOC was 7 (range, 1-45 cycles). Of the 39 patients, the PSA level decreased by >50% in 13 (33%). In the multivariate analysis of prediction of patient overall survival, a decrease of the PSA level to <50% was a significant predictor (hazard ratio = 6.913; 95% confidence interval: 1.147-41.669; P=0.035). The median cancer-specific overall survival from the diagnosis of CRPC was 16.7 months (range, 2-54 months). Grade 3 toxicities were observed in 5 patients (13%); specifically, limb edema, nausea and hepatic disorders were detected in 2 (5%), 2 (5%) and 1 patient (3%), respectively. Treatment-related death (grade 5) occurred in 1 patient due to interstitial pneumonia after two courses of chemotherapy. The chemotherapy was completed in the majority of the patients (n=37, 94.8%) in the outpatient department, without interruption. These findings suggest that weekly low-dose DOC is feasible and safe for selected patients with CRPC, without treament with novel agents, such as abiraterone, enzalutamide and cabazitaxel.

The development of abiraterone acetate for castration-resistant prostate cancer

Abiraterone acetate is a novel CYP17A1 inhibitor demonstrated to prolong survival in castration-resistant prostate cancer (CRPC). This review explores key stages in the almost 20-year history of abiraterone acetate׳s development, starting with a program aiming to develop inhibitors of androgen synthesis at the Institute of Cancer Research, London. Clinical development was initially slow owing to insufficient data supporting targeting of androgen synthesis as a therapeutic approach in CRPC and safety concerns of adrenocortical insufficiency from suppression of cortisol. Regulatory authorities approved abiraterone acetate in 2011 after a survival benefit was demonstrated when given in combination with prednisone as compared with prednisone alone in docetaxel-treated men. Licensing approval extended to include chemotherapy-naive patients with CRPC in 2012 following a significant increase in radiographic progression-free survival. Ongoing research focuses on identifying predictive biomarkers and understanding mechanisms of resistance to improve its administration.

Cancer Related Fatigue and Quality of Life in Patients with Advanced Prostate Cancer Undergoing Chemotherapy

Cancer related fatigue (CRF) is a common and debilitating symptom that can influence quality of life (QoL) in cancer patients. The increase in survival times stresses for a better understanding of how CRF affects patients' QoL. This was a cross-sectional descriptive study with 148 randomly recruited prostate cancer patients aiming to explore CRF and its impact on QoL. Assessments included the Cancer Fatigue Scale, EORTC QLQ-C30, and EORTC QLQ-PR25. Additionally, 15 in-depth structured interviews were performed. Quantitative data were analyzed with simple and multiple regression analysis and independent samples t-test. Qualitative data were analyzed with the use of thematic content analysis. The 66.9% of the patients experienced CRF with higher levels being recorded for the affective subscale. Statistically significant differences were found between the patients reporting CRF and lower levels of QoL (mean = 49.1) and those that did not report fatigue and had higher levels of QoL (mean = 72.1). The interviews emphasized CRF's profound impact on the patients' lives that was reflected on the following themes: “dependency on others,” “loss of power over decision making,” and “daily living disruption.” Cancer related fatigue is a significant problem for patients with advanced prostate cancer and one that affects their QoL in various ways.

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.

Prostate cancer

Much progress has been made in research for prostate cancer in the past decade. There is now greater understanding for the genetic basis of familial prostate cancer with identification of rare but high-risk mutations (eg, BRCA2, HOXB13) and low-risk but common alleles (77 identified so far by genome-wide association studies) that could lead to targeted screening of patients at risk. This is especially important because screening for prostate cancer based on prostate-specific antigen remains controversial due to the high rate of overdiagnosis and unnecessary prostate biopsies, despite evidence that it reduces mortality. Classification of prostate cancer into distinct molecular subtypes, including mutually exclusive ETS-gene-fusion-positive and SPINK1-overexpressing, CHD1-loss cancers, could allow stratification of patients for different management strategies. Presently, men with localised disease can have very different prognoses and treatment options, ranging from observation alone through to radical surgery, with few good-quality randomised trials to inform on the best approach for an individual patient. The survival of patients with metastatic prostate cancer progressing on androgen-deprivation therapy (castration-resistant prostate cancer) has improved substantially. In addition to docetaxel, which has been used for more than a decade, in the past 4 years five new drugs have shown efficacy with improvements in overall survival leading to licensing for the treatment of metastatic castration-resistant prostate cancer. Because of this rapid change in the therapeutic landscape, no robust data exist to inform on the selection of patients for a specific treatment for castration-resistant prostate cancer or the best sequence of administration. Moreover, the high cost of the newer drugs limits their widespread use in several countries. Data from continuing clinical and translational research are urgently needed to improve, and, crucially, to personalise management.

Prior Endocrine Therapy Impact on Abiraterone Acetate Clinical Efficacy in Metastatic Castration-resistant Prostate Cancer: Post-hoc Analysis of Randomised Phase 3 Studies

BACKGROUND

The duration of prior hormonal treatment can predict responses to subsequent therapy in patients with metastatic castration-resistant prostate cancer (mCRPC).

OBJECTIVE

To determine if prior endocrine therapy duration is an indicator of abiraterone acetate (AA) sensitivity.

DESIGN, SETTING, AND PARTICIPANTS

Post-hoc exploratory analysis of randomised phase 3 studies examining post-docetaxel (COU-AA-301) or chemotherapy-naïve mCRPC (COU-AA-302) patients receiving AA. The treatment effect on overall survival (OS), radiographic progression-free survival (rPFS), and prostate-specific antigen (PSA) response analysed by quartile duration of prior gonadotropin-releasing hormone agonists (GnRHa) or androgen receptor (AR) antagonist.

INTERVENTION

Patients were randomised to AA (1000mg, orally once daily) plus prednisone (5mg, orally twice daily) or placebo plus prednisone. Prior endocrine therapy was GnRHa (COU-AA-301, n=1127 [94%]; COU-AA-302, n=1057 [97%], 45.1 mo or 36.7 mo median duration, respectively) and/or orchiectomy (COU-AA-301, n=78 [7%] COU-AA-302, n=44 [4%]); castrated patients received prior AR antagonists (COU-AA-301, n=1015 [85%]; COU-AA-302, n=1078 [99%], 15.7 mo or 16.1 mo median duration, respectively).

OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS

Cox model was used to obtain hazard ratio and associated 95% confidence interval with statistical inference by log rank statistic.

RESULTS AND LIMITATIONS

Clinical benefit with AA was observed for OS, rPFS, and PSA response for nearly all quartiles with GnRHa or AR antagonists in both COU-AA-301 and COU-AA-302. In COU-AA-301, patients with a longer duration of prior endocrine therapy tended to have greater AA OS, rPFS, and PSA response benefit, with lead-time chemotherapy bias potentially impacting COU-AA-301 results. Time to castration resistance was not captured. This analysis is limited as a post-hoc exploratory analysis.

CONCLUSIONS

In the COU-AA-301 and COU-AA-302 studies, AA produced clinical benefits regardless of prior endocrine therapy duration in patients with mCRPC.

PATIENT SUMMARY

Metastatic castration-resistant prostate cancer patients derived clinical benefits with abiraterone acetate regardless of prior endocrine therapy duration.

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.

Metastatic castration-resistant prostate cancer (CRPC): preclinical and clinical evidence for the sequential use of novel therapeutics

With five novel therapies shown to improve survival in metastatic castration-resistant prostate cancer (CRPC) in the last 3 years, patients are now living longer and experiencing better quality of life. Since docetaxel became standard of care for men with symptomatic metastatic CRPC, three artificial treatment "spaces" have emerged for prostate cancer drug development: pre-docetaxel, docetaxel combinations, and following docetaxel. Multiple therapies are currently under development in both early and late stage CRPC. Additionally, the novel agents abiraterone, radium-223, cabazitaxel, and enzalutamide have all been approved in the post-docetaxel setting. Strategies for patient selection and treatment sequencing are therefore urgently required. In this comprehensive review, we will summarize the preclinical and clinical data available with regards to sequencing of the novel treatments for CRPC.

Systemic therapy in men with metastatic castration-resistant prostate cancer:American Society of Clinical Oncology and Cancer Care Ontario clinical practice guideline

PURPOSE

To provide treatment recommendations for men with metastatic castration-resistant prostate cancer (CRPC).

METHODS

The American Society of Clinical Oncology and Cancer Care Ontario convened an expert panel to develop evidence-based recommendations informed by a systematic review of the literature.

RESULTS

When added to androgen deprivation, therapies demonstrating improved survival, improved quality of life (QOL), and favorable benefit-harm balance include abiraterone acetate/prednisone, enzalutamide, and radium-223 ((223)Ra; for men with predominantly bone metastases). Improved survival and QOL with moderate toxicity risk are associated with docetaxel/prednisone. For asymptomatic/minimally symptomatic men, improved survival with unclear QOL impact and low toxicity are associated with sipuleucel-T. For men who previously received docetaxel, improved survival, unclear QOL impact, and moderate to high toxicity risk are associated with cabazitaxel/prednisone. Modest QOL benefit (without survival benefit) and high toxicity risk are associated with mitoxantrone/prednisone after docetaxel. No benefit and excess toxicity are observed with bevacizumab, estramustine, and sunitinib.

RECOMMENDATIONS

Continue androgen deprivation (pharmaceutical or surgical) indefinitely. Abiraterone acetate/prednisone, enzalutamide, or (223)Ra should be offered; docetaxel/prednisone should also be offered, accompanied by discussion of toxicity risk. Sipuleucel-T may be offered to asymptomatic/minimally symptomatic men. For men who have experienced progression with docetaxel, cabazitaxel may be offered, accompanied by discussion of toxicity risk. Mitoxantrone may be offered, accompanied by discussion of limited clinical benefit and toxicity risk. Ketoconazole or antiandrogens (eg, bicalutamide, flutamide, nilutamide) may be offered, accompanied by discussion of limited known clinical benefit. Bevacizumab, estramustine, and sunitinib should not be offered. There is insufficient evidence to evaluate optimal sequences or combinations of therapies. Palliative care should be offered to all patients.

Docetaxel in castration-resistant prostate cancer: a single-centre experience

We present a single-institution experience reporting the efficacy and safety of docetaxel, administered as first-line chemotherapy, in castration-resistant prostate cancer (CRPC), focusing on patients and treatment parameters. From November 2004 to January 2012, 51 patients received chemotherapy with docetaxel. With a mean follow-up time (from the beginning of CHT) of 1.6 years (range 0.1-5.1 years), 35 patients (68.6%) died for prostate cancer and 48 patients (94.1%) showed progression of the disease. Five factors influenced overall survival: nodal status at diagnosis, neoadjuvant hormonal therapy, number of cycles of docetaxel administered, schedule of docetaxel and ECOG performance status before starting chemotherapy.

Multidisciplinary consensus: a practical guide for the integration of abiraterone into clinical practice

Abiraterone improves survival, relieves pain, improves quality of life and extends time to prostate-specific antigen (PSA) progression in patients with metastatic castration-resistant prostate cancer (mCRPC). A consensus-based guide for using abiraterone in patients with mCRPC has been developed by Australian clinicians with expertise in prostate cancer, based on their experience and supported by published data. Recommendations were developed for eight key topics: abiraterone administration; steroid administration and duration of use; concomitant medications and drug interactions; timing of testing and monitoring response; safety in different populations; potential toxicities; precautions and contraindications; and referral and multidisciplinary care. Abiraterone is taken orally in a fasting state. Symptoms associated with mineralocorticoid excess are managed by coadministration of low-dose prednisone or prednisolone. Potassium levels, blood pressure and liver function need to be tested frequently during the early treatment phase. Response to treatment is monitored based on symptoms, radiological imaging and PSA levels. Potential adverse consequences of long-term steroid therapy on bone and metabolic health need to be screened for and managed. Advanced prostate cancer is best managed by a multidisciplinary team and early referral should be considered. Questions about the potential use of abiraterone in early disease and in combination with other therapies are being addressed in ongoing clinical trials.

Abiraterone acetate: a review of its use in patients with metastatic castration-resistant prostate cancer

Abiraterone acetate (Zytiga(®)) is an orally administered, selective inhibitor of the 17α-hydroxylase and C17,20-lyase enzymatic activities of cytochrome P450 (CYP) 17. CYP17 is required for androgen biosynthesis, with androgen receptor signalling crucial in the progression from primary to metastatic prostate cancer. Abiraterone acetate is approved in the European Union and the US, in combination with prednisone or prednisolone, for the treatment of men with metastatic castration-resistant prostate cancer (CRPC). When administered in combination with prednisone in a placebo-controlled, multinational phase III study, abiraterone acetate significantly prolonged overall survival and radiographic progression-free survival (rPFS) in men with metastatic CRPC who had previously received docetaxel. In men with metastatic CRPC who had not previously received chemotherapy participating in a placebo-controlled, multinational phase III study, there was a strong trend towards an overall survival benefit, a significant prolongation in rPFS and significant delays in clinical decline, the need for chemotherapy and the onset of pain observed. Given the nature of the therapy, the overall tolerability profile of abiraterone acetate, in combination with prednisone, was acceptable in men with metastatic CRPC. Abiraterone acetate is associated with hypokalaemia, hypertension, and fluid retention or oedema, secondary to its mechanism of action, and with cardiac adverse events and hepatotoxicity; however, in the phase III studies the incidences of the most frequently reported grade 3 or 4 adverse events of special interest were relatively low. Although the final overall survival data in men with metastatic CRPC who have not previously received chemotherapy are awaited, current evidence indicates that abiraterone acetate is a useful option for the treatment of metastatic CRPC.

Patient-reported outcome labeling claims and measurement approach for metastatic castration-resistant prostate cancer treatments in the United States and European Union

Background

Metastatic castration-resistant prostate cancer (mCRPC) and its treatment significantly affect health-related quality of life (HRQOL). Our objectives were to evaluate and compare patient-reported outcome (PRO) claims granted by the Food and Drug Administration (FDA) and European Medicines Agency (EMA) for 5 recently approved mCRPC treatments and to examine key characteristics, development, and measurement properties of the PRO measures supporting these claims against current regulatory standards.

Methods

Five products approved for treatment of mCRPC by the FDA and the EMA (2010–2013) were examined: enzalutamide, abiraterone, sipuleucel-T, cabazitaxel, and radium Ra 223 dichloride. United States (US) drug approval packages and European Public Assessment Reports were reviewed. PRO claims in the US labels and European Summaries of Product Characteristics and supporting measures were identified. For PRO measures supporting claims, a targeted literature review was conducted to identify information on key characteristics and measurement properties; this information was compared against FDA PRO guidance criteria.

Results

Nine PRO “claims” were granted across 4 of 5 products reviewed. The EMA granted more claims (7 claims—4 for pain, 3 for HRQOL) than the FDA (2 claims, both for pain). The Brief Pain Inventory–Short Form (BPI-SF) worst pain item supported most pain claims and was the only measure supporting US claims. EMA pain claims were supported by BPI-SF worst pain (n = 2) and average pain (n = 1) items and the McGill Pain Questionnaire Present Pain Intensity component (n = 1). EMA HRQOL claims were supported by the Functional Assessment of Cancer Therapy–Prostate Module (n = 2) and the EuroQol 5 Dimensions with visual analogue scale (n = 1). Pain and prostate cancer–specific HRQOL measures supporting claims met US regulatory standards for construct validity, reliability, and responsiveness; these properties were strongest for the BPI-SF worst pain item. Only the BPI-SF worst pain item has documented content validity in mCRPC.

Conclusions

PRO label claims were commonly granted across the mCRPC products reviewed. Among the measures reviewed, only the BPI-SF worst pain item supported US label claims. The BPI-SF worst pain item is recommended for pain assessment for the evaluation of new mCRPC treatments.

End points of clinical trials in metastatic castration-resistant prostate cancer: A systematic review

AIM: To review the definition and performance of the commonly used end points in trials of systemic therapies in metastatic castration-resistant prostate cancer patients.

METHODS: A literature search was undertaken on PubMed database to identify studies meeting established criteria, with the aim of selecting randomized clinical trials and study definition and performance of their end points. The end points were grouped into three categories: overall survival (OS), time-to-event end points, and response end points. A special analysis was performed for secondary end points of the studies which documented a benefit in OS in the experimental arm. Finally, publishes analyses for surrogacy of the included end points were also reported.

RESULTS: OS, time-to-event and response end points in 31 selected trials were analyzed. OS was the primary end point in 14 trials, and the secondary end point in 17. A time-to-event end point was the primary end point in 8 studies, and the secondary end point in 22; the most reported time-to-event end points were composite end points, and the events changed among trials. A response end point was the primary end point in 9 studies, in 3 it was prostate-specific antigen (PSA)-related, in 3 pain-related and in 3 mixed. A response end point was the secondary end point in 19 studies: PSA response and radiologic response were the most frequently used secondary end points in 19 and 11 trials, respectively, while pain response was used in 5 studies.

CONCLUSION: A homogeneous definition of progression in future trials is mandatory. Among response end points, pain-response and PSA-response appear to be the most reliable.

Updated interim efficacy analysis and long-term safety of abiraterone acetate in metastatic castration-resistant prostate cancer patients without prior chemotherapy (COU-AA-302)

BACKGROUND

Abiraterone acetate (an androgen biosynthesis inhibitor) plus prednisone is approved for treating patients with metastatic castration-resistant prostate cancer (mCRPC). Study COU-AA-302 evaluated abiraterone acetate plus prednisone versus prednisone alone in mildly symptomatic or asymptomatic patients with progressive mCRPC without prior chemotherapy.

OBJECTIVE

Report the prespecified third interim analysis (IA) of efficacy and safety outcomes in study COU-AA-302.

DESIGN, SETTING, AND PARTICIPANTS

Study COU-AA-302, a double-blind placebo-controlled study, enrolled patients with mCRPC from April 2009 to June 2010. A total of 1088 patients were stratified by Eastern Cooperative Oncology Group performance status (0 vs 1).

INTERVENTION

Patients were randomised 1:1 to abiraterone 1000mg plus prednisone 5mg twice daily by mouth versus prednisone.

OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS

Co-primary end points were radiographic progression-free survival (rPFS) and overall survival (OS). Median times to event outcomes were estimated using the Kaplan-Meier method. Hazard ratios (HRs) and 95% confidence intervals (CIs) were derived using the Cox model, and treatment comparison used the log-rank test. The O'Brien-Fleming Lan-DeMets α-spending function was used for OS. Adverse events were summarised descriptively.

RESULTS AND LIMITATIONS

With a median follow-up duration of 27.1 mo, improvement in rPFS was statistically significant with abiraterone treatment versus prednisone (median: 16.5 vs 8.2 mo; HR: 0.52 [95% CI, 0.45-0.61]; p<0.0001). Abiraterone improved OS (median: 35.3 vs 30.1 mo; HR: 0.79 [95% CI, 0.66-0.95]; p=0.0151) but did not reach the prespecified statistical efficacy boundary (α-level: 0.0035). A post hoc multivariate analysis for OS using known prognostic factors supported the primary results (HR: 0.74 [95% CI, 0.61-0.89]; p=0.0017), and all clinically relevant secondary end points and patient-reported outcomes improved. While the post hoc nature of the long-term safety analysis is a limitation, the safety profile with longer treatment exposure was consistent with prior reports.

CONCLUSIONS

The updated IA of study COU-AA-302 in patients with mCRPC without prior chemotherapy confirms that abiraterone delays disease progression, pain, and functional deterioration and has clinical benefit with a favourable safety profile, including in patients treated for ≥24 mo.

TRIAL REGISTRATION

Study COU-AA-302, ClinicalTrials.gov number, NCT00887198.

PATIENT SUMMARY

The updated results of this ongoing study showed that disease progression was delayed in patients with advanced prostate cancer who were treated with abiraterone acetate and prednisone, and there was a continued trend in prolongation of life compared with patients treated with prednisone alone. Treatment with abiraterone acetate and prednisone was well tolerated by patients who were treated for >2 yr.

Sequential use of novel therapeutics in advanced prostate cancer following docetaxel chemotherapy

In the last three years, five novel treatments have been shown to improve survival in metastatic castration-resistant prostate cancer (CRPC). These novel treatments have distinct mechanisms of action: tubulin-binding chemotherapy (cabazitaxel); immunotherapy (sipuleucel-T); CYP-17 inhibition (abiraterone); androgen receptor (AR) blockade (enzalutamide); and radioisotope therapy (radium-223). For a number of years, docetaxel was the only treatment with a proven survival benefit for patients with CRPC. Therefore, somewhat artificially, three treatment spaces for drug development in CRPC have emerged: pre-docetaxel; docetaxel combinations; and post-docetaxel. For patients progressing after docetaxel-based chemotherapy, treatment options available outside of clinical trials now include abiraterone, cabazitaxel and enzalutamide. Prospective data on how to best use these novel agents sequentially are not available. Clinicians face the difficult task of choosing between treatment options for individual patients to maximize patient benefit. Treatment evaluation in patients with CRPC remains challenging due to the predominance of bone metastatic disease and the lack of validated surrogate markers for survival. This review summarizes the data available with regards to sequencing of the novel treatments for CRPC.

Abiraterone in the treatment of metastatic castration-resistant prostate cancer

Androgen deprivation therapy remains the single most effective treatment for the initial therapy of advanced prostate cancer, but is uniformly marked by progression to castration-resistant prostate cancer (CRPC). Residual tumor androgens and androgen axis activation are now recognized to play a prominent role in mediating CRPC progression. Despite suppression of circulating testosterone to castrate levels, castration does not eliminate androgens from the prostate tumor microenvironment and residual androgen levels are well within the range capable of activating the androgen receptor (AR) and AR-mediated gene expression. Accordingly, therapeutic strategies that more effectively target production of intratumoral androgens are necessary. The introduction of abiraterone, a potent suppressor of cytochrome P450 17 α-hydroxysteroid dehydrogenase-mediated androgen production, has heralded a new era in the hormonal treatment of men with metastatic CRPC. Herein, the androgen and AR-mediated mechanisms that contribute to CRPC progression and establish cytochrome P450 17 α-hydroxysteroid dehydrogenase as a critical therapeutic target are briefly reviewed. The mechanism of action and pharmacokinetics of abiraterone are reviewed and its recently described activity against AR and 3-β-hydroxysteroid dehydrogenase is discussed. The Phase I and II data initially demonstrating the efficacy of abiraterone and Phase III data supporting its approval for patients with metastatic CRPC are reviewed. The safety and tolerability of abiraterone, including the incidence and management of side effects and potential drug interactions, are discussed. The current place of abiraterone in CRPC therapy is reviewed and early evidence regarding cross-resistance of abiraterone with taxane therapy, mechanisms of resistance to abiraterone, and observations of an abiraterone withdrawal response are presented. Future directions in the use of abiraterone, including optimal dosing strategies, the role of abiraterone in earlier disease settings, including castration sensitive, biochemically recurrent, or localized disease, and the rationale for combinatorial treatment strategies of abiraterone with enzalutamide and other targeted agents are also discussed.