Outcomes with abiraterone acetate in metastatic castration-resistant prostate cancer patients who have poor performance status

Examining Exclusion Criteria in Advanced Prostate Cancer Clinical Trials: An Assessment of recommendations From the American Society Of Clinical Oncology and Friends of Cancer Research

PURPOSE

Eligibility criteria illustrate the characteristics of the study population and promote the safety of participants. However, overreliance on restrictive eligibility criteria may limit the generalizability of outcomes. As a result, the American Society of Clinical Oncology (ASCO) and Friends of Cancer Research (Friends) issued statements to curtail these challenges. In this study, we aimed to assess restrictiveness in eligibility criteria across advanced prostate cancer clinical trials.

MATERIALS AND METHODS

We identified all phase I, II, and III advanced prostate cancer clinical trials between June 30, 2012, and June 30, 2022, through Clinicaltrials.gov. We evaluated whether a clinical trial excluded, conditionally included, or did not report 4 common criteria: brain metastases, prior or concurrent malignancies, HIV infection, and hepatitis B virus (HBV)/hepatitis C virus (HCV) infection. Performance status (PS) criteria were recorded based on the Eastern Cooperative Oncology Group (ECOG) scale.

RESULTS

Out of 699 clinical trials within our search strategy, 265 (37.9%) trials possessed all the required data and were included in our analysis. The most common excluded condition of our interest was brain metastases (60.8%), followed by HIV positivity (46.4%), HBV/HCV positivity (46.0%), and concurrent malignancies (15.5%). Additionally, 50.9% of clinical trials only included patients with ECOG PS 0 to 1. HIV and HBV/HCV infection were exclusion criteria of 22 (80.8%) and 19 (73.1%) immunotherapy trials, respectively.

CONCLUSION

Patients with brain metastases, prior or concurrent malignancies, HIV infection, HBV/HCV infection, or low-functioning PS were overly restricted from participating in advanced prostate clinical trials. Advocating for broader criteria may ameliorate generalizability.

Low Alanine Aminotransferase, as a Marker of Sarcopenia and Frailty, Is Associated with Shorter Survival Among Prostate Cancer Patients and Survivors. A Retrospective Cohort Analysis of 4064 Patients

Background

Sarcopenia is characterized by loss of muscle mass and function and is associated with frailty, a syndrome with higher likelihood of falls, fractures, physical disability, and mortality. Both frailty and sarcopenia are known markers of shorter survival in various cancer patient populations. Low alanine aminotransferase (ALT), reflecting loss of muscle mass (sarcopenia), may be associated with greater frailty and shorter survival in multiple cancers.

Objective

To assess the potential association between low ALT and shorter survival among prostate cancer (PCa) patients and survivors.

Design setting and participants

This was a retrospective analysis of a historical cohort of PCa patients and survivors. Patients were defined as those still actively receiving PCa treatment, while those no longer receiving such treatment were classified as PCa survivors.

Outcome measurements and statistical analysis

ALT data were obtained from results for basic biochemical blood testing carried out for patients on their first hospital admission. Patients were divided into two groups: those with ALT ≥17 IU/l and those with ALT <17 IU/l. Univariate and multivariable analyses were conducted for between-group survival comparisons.

Results and limitations

We identified 9489 PCa records. The final study cohort with ALT data available included 4064 patients with ALT <40 IU/l. Of this cohort, 536 patients were actively receiving medical anticancer therapy for PCa. The mean age for the entire cohort was 74.6 yr (standard deviation 9.6) and the median ALT level was 19.28 IU/l; 1676 patients (41%) had low ALT (<17 IU/l). On univariate analysis, low ALT was associated with a 78% increase in mortality risk (95% confidence interval [CI] 1.62-1.97; p < 0.001). A sensitivity analysis of the 536 patients actively receiving medical anticancer treatment revealed that low ALT was associated with a 48% increase in mortality risk (95% CI 1.19-1.85; p = 0.001). In a multivariable model controlled for age, kidney disease, history of cerebrovascular event/transient ischemic attack, and baseline prostate-specific antigen, low ALT was still associated with a 35% increase in mortality risk (95% CI 1.12-1.63; p = 0.001). Limitations include the single-center, retrospective design.

Conclusions

Low ALT, which is indicative of sarcopenia and frailty, is associated with shorter survival among PCa patients and survivors and could potentially be used for treatment personalization.

Patient summary

We compared survival for prostate cancer patients and survivors according to their blood level of the protein alanine aminotransferase (ALT). Low ALT levels in the general population are associated with loss of muscle mass. We found that in our group of prostate cancer patients and survivors, the risk of death from any cause was higher for those with low ALT levels.

Impact of DNA damage repair alterations on prostate cancer progression and metastasis

Prostate cancer is among the most common diseases worldwide. Despite recent progress with treatments, patients with advanced prostate cancer have poor outcomes and there is a high unmet need in this population. Understanding molecular determinants underlying prostate cancer and the aggressive phenotype of disease can help with design of better clinical trials and improve treatments for these patients. One of the pathways often altered in advanced prostate cancer is DNA damage response (DDR), including alterations in BRCA1/2 and other homologous recombination repair (HRR) genes. Alterations in the DDR pathway are particularly prevalent in metastatic prostate cancer. In this review, we summarise the prevalence of DDR alterations in primary and advanced prostate cancer and discuss the impact of alterations in the DDR pathway on aggressive disease phenotype, prognosis and the association of germline pathogenic alterations in DDR genes with risk of developing prostate cancer.

Factors Associated with Long-Term Prostate Cancer Survival after Palliative Radiotherapy to a Bone Metastasis and Contemporary Palliative Systemic Therapy: A Retrospective, Population-Based Study

BACKGROUND

Radiation therapy (RT) is an established palliative treatment for bone metastases; however, little is known about post-radiation survival and factors which impact it. The aim of this study was to assess a population-based sample of metastatic prostate cancer patients receiving palliative radiation therapy to bone metastases and contemporary palliative systemic therapy and identify factors that impact long-term survival.

MATERIALS/METHODS

This retrospective, population-based, cohort study assessed all prostate cancer patients receiving palliative RT for bone metastases at a Canadian provincial Cancer program during a contemporary time period. Baseline patient, disease, and treatment characteristics were extracted from the provincial medical physics databases and the electronic medical record. Post-RT Survival intervals were defined as the time interval from the first fraction of palliative RT to death from any cause or date of the last known follow-up. The median survival of the cohort was used to dichotomize the cohort into short- and long-term survivors following RT. Univariable and multivariable hazard regression analyses were performed to identify variables associated with post-RT survival.

RESULTS

From 1 January 2018 until 31 December 2019, 545 palliative RT courses for bone metastases were delivered to n = 274 metastatic prostate cancer patients with a median age of 76 yrs (Interquartile range (IQR) 39-83) and a median follow-up of 10.6 months (range 0.2 to 47.9). The median survival of the cohort was 10.6 months (IQR 3.5-25 months). The ECOG performance status of the whole cohort was ≤2 in n = 200 (73%) and 3-4 in n = 67 (24.5%). The most commonly treated sites of bone metastasis were the pelvis and lower extremities n = 130 (47.4%), skull and spine n = 114 (41.6%), and chest and upper extremities n = 30 (10.9%). Most patients had CHAARTED high volume disease n = 239 (87.2%). On multivariable hazard regression analysis, an ECOG performance status of 3-4 (p = 0.02), CHAARTED high volume disease burden (p = 0.023), and non-receipt of systemic therapy (p = 0.006) were significantly associated with worse post-RT survival.

CONCLUSION

Amongst metastatic prostate cancer patients treated with palliative radiotherapy to bone metastases and modern palliative systemic therapies, ECOG performance status, CHAARTED metastatic disease burden, and type of first-line palliative systemic therapy were significantly associated with post-RT survival durations.

Time on treatment with abiraterone and enzalutamide in the Patient-overview Prostate Cancer in The National Prostate Cancer Register of Sweden

BACKGROUND

There are little and inconsistent data from clinical practice on time on treatment with the androgen receptor-targeted drugs (ART) abiraterone and enzalutamide in men with metastatic castration-resistant prostate cancer (mCRPC). We assessed time on treatment with ART and investigated predictors of time on treatment.

MATERIAL AND METHODS

Time on treatment with ART in men with mCRPC in the patient-overview prostate cancer (PPC), a subregister of the National Prostate Cancer Register (NPCR) of Sweden, was assessed by use of Kaplan-Meier plots and Cox regression. To assess the representativity of PPC for time on treatment, a comparison was made with all men in NPCR who had a filling for ART in the Prescribed Drug Registry.

RESULTS

2038 men in PPC received ART between 2015 and 2019. Median time on treatment in chemo-naïve men was 10.8 (95% confidence interval 9.1-13.1) months for abiraterone and 14.1 (13.5-15.5) for enzalutamide. After the use of docetaxel, time on treatment was 8.2 (6.5-12.4) months for abiraterone and 11.1 (9.8-12.6) for enzalutamide. Predictors of a long time on treatment with ART were long duration of ADT prior to ART, low serum levels of PSA at start of ART, absence of visceral metastasis, good performance status, and no prior use of docetaxel. PPC captured 2522/6337 (40%) of all men in NPCR who had filled a prescription for ART. Based on fillings in the Prescribed Drug Registry, men in PPC had a slightly longer median time on treatment with ART compared to all men in NPCR, 9.6 (9.1-10.3) vs. 8.6 (6.3-9.1) months.

CONCLUSIONS

Time on treatment in clinical practice was similar or shorter than that in published RCTs, due to older age, poorer performance status and more comorbidities.

Early molecular imaging response assessment based on determination of total viable tumor burden in [68Ga]Ga-PSMA-11 PET/CT independently predicts overall survival in [177Lu]Lu-PSMA-617 radioligand therapy

Purpose

In patients with metastatic castration-resistant prostate cancer (mCRPC) treated with prostate-specific membrane antigen-targeted radioligand therapy (PSMA-RLT), the predictive value of PSMA PET/CT-derived response is still under investigation. Early molecular imaging response based on total viable tumor burden and its association with overall survival (OS) was explored in this study.

Methods

Sixty-six mCRPC patients who received [¹⁷⁷Lu]Lu-PSMA-617 RLT within a prospective patient registry (REALITY Study, NCT04833517) were analyzed. Patients received a [⁶⁸Ga]Ga-PSMA-11 PET/CT scan before the first and after the second cycle of PSMA-RLT. Total lesion PSMA (TLP) was determined by semiautomatic whole-body tumor segmentation. Molecular imaging response was assessed by change in TLP and modified PERCIST criteria. Biochemical response was assessed using standard serum PSA and PCWG3 criteria. Both response assessment methods and additional baseline parameters were analyzed regarding their association with OS by univariate and multivariable analysis.

Results

By molecular imaging, 40/66 (60.6%) patients showed partial remission (PR), 19/66 (28.7%) stable disease (SD), and 7/66 (10.6%) progressive disease (PD). Biochemical response assessment revealed PR in 34/66 (51.5%) patients, SD in 20/66 (30.3%), and PD in 12/66 (18.2%). Response assessments were concordant in 49/66 (74.3%) cases. On univariate analysis, both molecular and biochemical response (p = 0.001 and 0.008, respectively) as well as two baseline characteristics (ALP and ECOG) were each significantly associated with OS. The median OS of patients showing molecular PR was 24.6 versus 10.7 months in the remaining patients (with SD or PD). On multivariable analysis molecular imaging response remained an independent predictor of OS (p = 0.002), eliminating biochemical response as insignificant (p = 0.515).

Conclusion

The new whole-body molecular imaging–derived biomarker, early change of total lesion PSMA (TLP), independently predicts overall survival in [¹⁷⁷Lu]Lu-PSMA-617 RLT in mCRPC, outperforming conventional PSA-based response assessment. TLP might be considered a more distinguished and advanced biomarker for monitoring PSMA-RLT over commonly used serum PSA.

Modernizing Clinical Trial Eligibility Criteria: Recommendations of the ASCO-Friends of Cancer Research Performance Status Work Group

PURPOSE

Performance status (PS) is one of the most common eligibility criteria. Many trials are limited to patients with high-functioning PS, resulting in important differences between trial participants and patient populations with the disease. In addition, existing PS measures are subjective and susceptible to investigator bias.

EXPERIMENTAL DESIGN

A multidisciplinary working group of the American Society of Clinical Oncology and Friends of Cancer Research evaluated how PS eligibility criteria could be more inclusive. The working group recommendations are based on a literature search, review of trials, simulation study, and multistakeholder consensus. The working group prioritized inclusiveness and access to investigational therapies, while balancing patient safety and study integrity.

RESULTS

Broadening PS eligibility criteria may increase the number of potentially eligible patients for a given clinical trial, thus shortening accrual time. It may also result in greater participant diversity, potentially reduce trial participant and patient disparities, and enable clinicians to more readily translate trial results to patients with low-functioning PS. Potential impact on outcomes was explored through a simulation trial demonstrating that when the number of Eastern Cooperative Oncology Group PS2 participants was relatively small, the effect on the estimated HR and power was modest, even when PS2 patients did not derive a treatment benefit.

CONCLUSIONS

Expanding PS eligibility criteria to be more inclusive may be justified in many cases and could result in faster accrual rates and more representative trial populations.See related commentary by Giantonio, p. 2369.

Prognostic value of ECOG performance status and Gleason score in the survival of castration-resistant prostate cancer: a systematic review

Eastern Cooperative Oncology Group (ECOG) performance status and Gleason score are commonly investigated factors for overall survival (OS) in men with castration-resistant prostate cancer (CRPC). However, there is a lack of consistency regarding their prognostic or predictive value for OS. Therefore, we performed this meta-analysis to assess the associations of ECOG performance status and Gleason score with OS in CRPC patients and compare the two markers in patients under different treatment regimens or with different chemotherapy histories. A systematic literature review of monotherapy studies in CRPC patients was conducted in the PubMed database until May 2019. The data from 8247 patients in 34 studies, including clinical trials and real-world data, were included in our meta-analysis. Of these, twenty studies reported multivariate results and were included in our main analysis. CRPC patients with higher ECOG performance statuses (≥ 2) had a significantly increased mortality risk than those with lower ECOG performance statuses (<2), hazard ratio (HR): 2.10, 95% confidence interval (CI): 1.68-2.62, and P < 0.001. The synthesized HR of OS stratified by Gleason score was 1.01, with a 95% CI of 0.62-1.67 (Gleason score ≥ 8 vs <8). Subgroup analysis showed that there was no significant difference in pooled HRs for patients administered taxane chemotherapy (docetaxel and cabazitaxel) and androgen-targeting therapy (abiraterone acetate and enzalutamide) or for patients with different chemotherapy histories. ECOG performance status was identified as a significant prognostic factor in CRPC patients, while Gleason score showed a weak prognostic value for OS based on the available data in our meta-analysis.

Observational study on time on treatment with abiraterone and enzalutamide

Introduction

The aim of this study was to assess time on treatment with abiraterone and enzalutamide, two androgen receptor targeted (ART) drugs, the impact on time on treatment of time interval without drug supply between prescription fillings, and adherence to treatment.

Material and methods

By use of data from The National Prostate Cancer Register, The Prescribed Drug Registry and the Patient Registry, time on treatment with the abiraterone and enzalutamide was analyzed in all men with castration resistant prostate cancer (CRPC) in Sweden 2015–2019. Three time intervals between consecutive fillings, i.e. time without drug supply, were assessed. Adherence to the treatment was evaluated by use of the Medication Possession Ratio. Kaplan Meier analysis and multivariable Cox regression model were used to assess factors affecting time on treatment.

Results

Between January 2015 and October 2019, 1803 men filled a prescription for abiraterone and 4 534 men filled a prescription for enzalutamide. With a time interval of 30 days or less between two fillings, median time on treatment was 4.9 months (IQR 2.6–11.7) for abiraterone and 8.0 months (IQR 3.6–16.4) for enzalutamide. In sensitivity analyses, allowing for no more than 14 days without drug supply between fillings, median time on treatment was 3.9 months (IQR 2.1–9.0) for abiraterone and 5.9 months (IQR 2.8–12.1) for enzalutamide. Allowing for any time period without drug between fillings, median time on treatment was 5.7 months (IQR 2.7–14.0) for abiraterone and 9.8 months (IQR 4.4–21.0) for enzalutamide. Adherence to treatment was above 90% for both drugs.

Conclusion

Time on treatment with abiraterone and enzalutamide was shorter in clinical practice than in randomized controlled trials and varied almost two-fold with time interval without drug. Adherence to treatment was high. The main limitation of our study was the lack of data on use of chemotherapy.

Efficacy of abiraterone acetate in castration-resistant metastatic prostate cancer: A real-world data analysis

PURPOSE

The aim of this study was to evaluate the efficacy of abiraterone in patients with castration-resistant metastatic prostate cancer.

MATERIALS AND METHODS

We retrospectively analyzed 51 patients with mCRPC treated with abiraterone acetate from January 2014 to August 2018. Clinicopathological information, treatment modalities, treatment responses, and survival times were retrospectively reviewed.

RESULTS

A total of 51 patients who received abiraterone 1000 mg/day + prednisone 10 mg/day between January 2014 and August 2018 were included in the study. Of these patients, 33 (64.7%) had post-chemotherapy (CT) and 18 (35.3%) had CT-naive abiraterone receipt. Median overall survival (OS) was 17.3 months (range 9.3-33.1). Median OS was found to be 12.7 months (range 9.4-18.3) and 29.4 months (range 9.3-33.0) in the CT-naive and post-CT group, respectively (P = .236). Median radiographic PFS (rPFS) was 10.1 months (range 4.5-18.4). In the CT-naive group, rPFS was 10.1 months (IQR 6.0-14.7) and in the post-CT group, it was 9.7 months (range 4.0-18.4) (P = .808). PSA progression-free survival (PSA-PFS) was 9.1 months (range 4.6-13.1). In the CT-naive group, PSA-PFS was 7.4 months (range 4.6-13.4) and in post-CT, it was 9.1 months (range 4.8-13.1) (P = .843).

CONCLUSIONS

These results show that abiraterone acetate is an effective and reliable agent in real-life data.

Is the duration of castration resistance predictive for sequential treatment responses in the metastatic castration-resistant prostate cancer setting?

OBJECTIVE

Prostate cancer is the second leading cause of cancer death in men. Androgen deprivation therapy (ADT) has been the primary therapeutic approach for treatment of prostate cancer. However,nearly all patients develop the castration-resistant disease . We evaluated real-world data with abiraterone and enzalutamide treatment. By this data, we aimed to analyze whether that prior short response to ADT could predict response to subsequent therapy with androgen receptor axis targeted agent (ARATA).

MATERIAL AND METHOD

We collected data from two cancer centers, 151 consecutive patients with treated abiraterone or enzalutamide in the first line of metastatic castration resistant prostat cancer (mCRPC) setting were included. The patients who received docetaxel in castration naive setting is also included. Time to castration resistance (TTCR) was defined as the duration from the initial to failure of primary ADT.

RESULTS

Patients with treated ARATA were divided into two groups according to the time to castration resistance (TTCR). Patients who became resistant to ADT up to one year had a median PFS of 6.6 months, compared to median PFS of 13.3 months for patients who responded ADT for more than 1 year. (p = 0.002). In the post-docetaxel setting, median PFS is 12.6 months of patients with treated ARATA who had TTCR for more than one year, and median PFS is 6.6 months in those who had TTCR less than one year (p = 0.007).Univariate and multivariate analyses were performed to determine the clinical factors on ARATA outcomes. Eastern Cooperative Oncology Group (ECOG) performance status(PS), median prostate-specific antigen(PSA) and time to CRPC were significantly predicted outcomes of ARATA on multivariate analysis.

CONCLUSION

TTCR is also a predictor for PFS of the patients who were treated ARATA both whole cohort and post-docetaxel.

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.

Prognostic Value of 18F-Fluorocholine PET Parameters in Metastatic Castrate-Resistant Prostate Cancer Patients Treated with Docetaxel

Background and Aim

The availability of new treatments for metastatic castrate-resistant prostate cancer (mCRPC) patients increases the need for reliable biomarkers to help clinicians to choose the better sequence strategy. The aim of the present retrospective and observational work is to investigate the prognostic value of ¹⁸F-fluorocholine (¹⁸F-FCH) positron emission tomography (PET) parameters in mCRPC.

Materials and Methods

Between March 2013 and August 2016, 29 patients with mCRPC were included. They all received three-weekly docetaxel after androgen deprivation therapy, and they underwent ¹⁸F-FCH PET/computed tomography (CT) before and after the therapy. Semi-quantitative indices such as maximum standardized uptake value (SUV_max), mean standardized uptake value (SUV_mean) with partial volume effect (PVC-SUV) correction, metabolically active tumour volume (MATV), and total lesion activity (TLA) with partial volume effect (PVC-TLA) correction were measured both in pre-treatment and post-treatment ¹⁸F-FCH PET/CT scans for each lesion. Whole-body indices were calculated as sum of values measured for each lesion (SSUV_max, SPVC-SUV, SMATV, and STLA). Progression-free survival (PFS) and overall survival (OS) were considered as clinical endpoints. Univariate and multivariate hazard ratios for whole-body ¹⁸F-FCH PET indices were performed, and p < 0.05 was considered as significant.

Results

Cox regression analysis showed a statistically significant correlation between PFS, SMATV, and STLA. No correlations between OS and ¹⁸F-FCH PET parameters were defined probably due to the small sample size.

Conclusions

Semi-quantitative indices such as SMATV and STLA at baseline have a prognostic role in patients treated with docetaxel for mCRPC, suggesting a potential role of ¹⁸F-FCH PET/CT imaging in clinical decision-making.

Abiraterone acetate for chemotherapy-naive metastatic castration-resistant prostate cancer: a single-centre prospective study of efficacy, safety, and prognostic factors

Background

To evaluate the efficacy and safety of abiraterone acetate (AA) plus prednisone compared with prednisone alone in Asian patients with chemotherapy-naive metastatic castration-resistant prostate cancer (mCRPC), and to identify predictive factors.

Methods

We reviewed the medical records of 60 patients with chemotherapy-naive mCRPC at Renji Hospital who were treated with AA plus prednisone (n = 43) or prednisone alone (n = 17). All patients were assessed for prostate-specific antigen (PSA) response, PSA progression-free survival (PSA PFS), radiographic progression-free survival (rPFS), and overall survival (OS). The ability of several parameters to predict PSA PFS, rPFS, and OS was studied.

Results

The median follow-up time was 14.0 months (range 7.0–18.5 months), at which time 19 death events had been reported: 11 in the AA + prednisone group and 8 in the prednisone group. The AA + prednisone group had significantly longer median PSA PFS (10.3 vs 3.0 months, P < 0.001), rPFS (13.9 vs 3.9 months, P < 0.001), and OS (23.3 vs 17.5 months, P = 0.016) than the prednisone-alone group. The most frequently reported grade 3 or 4 adverse event in both the AA + prednisone and prednisone-alone groups was elevated alanine aminotransferase level in 5 of 43 patients (11.6%) and 2 of 17 patients (11.8%), respectively. No adverse events led to discontinuation of therapy. In multivariate analysis, time from androgen deprivation therapy (ADT) to castration resistance of ≤18 months was a determinant of shorter OS (P = 0.007).

Conclusions

These results support the favourable safety and efficacy profile of AA for the treatment of Asian patients with chemotherapy-naive mCRPC. Longer duration of ADT response was significantly associated with longer survival.

Electronic supplementary material

The online version of this article (10.1186/s12894-018-0416-6) contains supplementary material, which is available to authorized users.

What kind of patients with castration-naïve prostate cancer can benefit from upfront docetaxel and abiraterone: A systematic review and a network meta-analysis

We conducted a systematic network meta-analysis to review the relevant literature evaluating the therapeutic efficacy of upfront docetaxel (Doc) or abiraterone (Abi) plus androgen deprivation therapy (ADT) on oncological outcome in patients with castration-naïve prostate cancer (CNPC). An attempt to identify subgroups of patients who would benefit most either from Doc or Abi plus ADT and further compare the efficacy and safety between these two combination therapies was made. A comprehensive search of the PubMed/Medline, Embase databases, International Clinical Trial Registration Platform (ICTRP), Clinical Trial, and Cochrane Central Register of Controlled Trials to December 2017 was performed. Six studies, involving 6480 patients, were included in this meta-analysis, consisting of over 60% (4462/6480) of patients with metastatic CNPC (mCNPC, M1), and 31.1% (2018/6480) of patients with non-metastatic CNPC (M0). In total, combination therapies (ADT plus Doc or Abi) significantly improved overall survival (OS) and failure-free survival (FFS) for all CNPC patients. For M1 patients, combination therapies were dramatically associated with improved OS and FFS, but for M0 patients, only with moderate improvement in FFS. M1 patients < 70 years old, Eastern Cooperative Oncology Group (ECOG) performance status (ECOG PS) 0-1, Gleason score (< 8), or visceral metastases could realize better survival benefit from either combination therapy. In indirect comparisons among M1 patients with younger age (< 70 years), ECOG PS 0-1 or aggressive Gleason score (GS ≥ 8), upfront Abi showed superiority to Doc in prolonging FFS. The incidence of severe adverse events (AEs ≥ 3) was comparable between these two therapeutic regimens. In conclusion, upfront Doc or Abi plus ADT should be considered a standard of care in selected patients with mCNPC. For a subset of populations, Abi may be the first choice for men who start treatment for the first time.

A prognostic model for stratifying clinical outcomes in chemotherapy-naive metastatic castration-resistant prostate cancer patients treated with abiraterone acetate

INTRODUCTION

Recently, a prognostic index including six risk factors (RFs) (unfavourable Eastern Cooperative Oncology Group performance status [ECOG PS], presence of liver metastases, short response to luteinizing hormone-releasing hormone [LHRH] agonists/antagonists, low albumin, increased alkaline phosphatase [ALP] and lactate dehydrogenase [LDH]) was developed from the COU-AA-301 trial in post-chemotherapy metastatic castration-resistant prostate cancer (mCRPC) patients treated with abiraterone acetate. Our primary objective was to evaluate this model in a cohort of chemotherapy-naive mCRPC patients receiving abiraterone.

METHODS

We identified 197 chemotherapy-naive patients who received abiraterone at six BC Cancer Agency centres and who had complete information on all six RFs. Study endpoints were prostate-specific antigen (PSA) response rate (RR), time to PSA progression, time on treatment, and overall survival (OS). PSA RR and survival outcomes were compared using Χ2 test and log-rank test. Multivariable Cox proportional hazard analysis was performed to identify RFs independently associated with OS.

RESULTS

Patients were classified into good (0-1 RFs), intermediate (2-3 RFs), and poor (4-6 RFs) prognostic groups (33%, 52%, and 15%, respectively). For good-, intermediate-, and poor-risk patients, PSA RR (≥50% decline) was 60% vs. 42% vs. 40% (p=0.05); median time to PSA progression was 7.3 vs. 5.3 vs. 5.0 months (p=0.02); and median OS was 29.4 vs. 13.8 vs. 8.7 months (p<0.0001).

CONCLUSIONS

The six-factor prognostic index model stratifies clinical outcomes in chemotherapy-naive mCRPC patients treated with abiraterone. Identifying patients at risk of poor outcome is important for informing clinical practice and clinical trial design.

Abiraterone acetate + prednisolone treatment beyond prostate specific antigen and radiographic progression in metastatic castration-resistant prostate cancer patients

OBJECTIVES

To investigate the overall survival (OS) of chemotherapy refractory patients with metastatic castration-resistant prostate cancer who were treated with abiraterone acetate + prednisolone (AA + P) beyond prostate specific antigen (PSA) and radiographic progression (PRP) until clinical progression in comparison to patients treated until PRP.

METHODS

At our institute the AA + P treatment started in 2011 in an early-access protocol trial. In October 2012 AA became generally available. From April 2011 to November 2014, 116 patients received AA + P. The clinical trial patients (T; n = 56) were treated beyond PRP until clinical progression. In the nonclinical trial group (NT; n = 57) the treatment was covered until PRP. Three patients are still under treatment. The 2 groups were statistically homogeneous, except AA + P treatment duration. The primary objective was the OS and the secondary the PSA progression-free and radiographic progression-free survivals.

RESULTS

The median OS was significantly longer (P<0.0001) in the T group compared to the NT group: 21.9 (95% CI: 16.9-25) vs. 12.5 (9.3-14.1) months, respectively. In univariate analysis there were 11 parameters, which significantly affected OS, but in multivariate Cox analysis only alkaline phosphatase (AP) level at the start of treatment, systemic therapy after AA + P and cohort type (T or NT) proved to independently influence the OS. The progression-free survival curves of T and NT groups did not differ significantly.

CONCLUSIONS

In our retrospective analysis low levels of AP at the start of treatment, systemic therapy applied after AA + P and treatment beyond PRP proved to be independent factors of longer OS in metastatic castration-resistant prostate cancer.

A population-based study of the use of radium 223 in metastatic castration-resistant prostate cancer: Factors associated with treatment completion

INTRODUCTION

Radium 223 (Ra223) given for six cycles has proven efficacy in clinical trials, but its population-level generalizability has not been well-described. The objectives of this study were to describe population-based Ra223 use in the abiraterone and enzalutamide era and identify factors associated with completion.

METHODS

All Ra223 patients at the British Columbia Cancer Agency between September 2013 and February 2016 were identified. Patients who completed <5 vs. ≥5 cycles were compared on patient characteristics, lines of prior therapy, prostate-specific antigen (PSA) and alkaline phosphatase (ALP) decline >30% from baseline (R30%), and survival, to identify factors associated with therapy completion.

RESULTS

Ninety-one patients were identified; 48 (52.7%) completed >5 cycles. Median overall survival (mOS) was 10.7 months, PSA and ALP R30% were 21% and 52%, respectively. Completion of <5 cycles was associated with higher baseline ALP (p=0.05) and lower baseline hemoglobin (Hb) levels (p=0.03). Patients in the ≥5 cycles group had longer mOS than those in the <5 cycles group (16.2 vs. 5.9 months; p<0.0001), as well as higher PSA R30% (33.3% vs. 7.0%; p=0.002) and ALP R30% (66.7% vs. 34.9%; p=0.03). Patients with ALP ≥220 and Hb ≤118 had 3.85 times the odds of not completing ≥5 cycles vs. ALP <220 and Hb >118.

CONCLUSIONS

Compared to clinical trials, patients in a population-based setting had more lines of therapy and shorter survival. Lower ALP and higher hemoglobin were associated with completion of >5 cycles, longer mOS, and greater incidence of PSA and ALP response.

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.

Evaluation of Prostate Cancer with 11C-Choline PET/CT for Treatment Planning, Response Assessment, and Prognosis

The aim of this review is to report on the value of ¹¹C-choline PET imaging as a diagnostic procedure for metastasis-directed therapies. Furthermore, the role of ¹¹C-choline PET/CT as a diagnostic tool for monitoring castration-resistant prostate cancer patients treated with systematic therapy is assessed. Finally, the role of ¹¹C-choline PET/CT in the prediction of survival in both castration-resistant prostate cancer patients and hormone-naïve patients is investigated.

First Line Androgen Deprivation Therapy Duration Is Associated with the Efficacy of Abiraterone Acetate Treated Metastatic Castration-Resistant Prostate Cancer after Docetaxel

Introduction: We performed a chart review study in our castration-resistant prostate cancer (CRPC) patients who received Abiraterone acetate (AA) treatment after docetaxel and identified clinical markers which can predict treatment outcome. Materials and Methods: From 2012 to 2016, 64 patients who received docetaxel after CRPC followed by AA treatment were included. Clinical parameters were recorded and analysis was performed to identify associations between pre-treatment variables and treatment outcome. Results: Thirty three patients (51.6%) achieved a decrease in PSA of 50%. The median PSA progression-free survival and overall survival in the total cohort of 64 patients were 6.6 and 24 months, respectively. Adverse events (AEs) in all grades developed in 35.9% (23/64) patients and mostly were grade 1 or 2. The most common AEs were gastric upset, hypokalemia and elevated liver function tests. Of the eight variables analyzed, first line androgen deprivation therapy (ADT) duration showed positive association to progression free survival (HR 0.98, 95% CI [0.96-0.99], p = 0.012) and overall survival (HR 0.97, 95% CI [0.94-0.99], p = 0.019). Pre-AA PSA and PSA progression ratio showed negative association only to progression free survival (HR 1.0, 95% CI [1.000-1.002], p = 0.025, HR 1.01, 95% CI [1.00-1.01], p < 0.001, respectively). Conclusion: First line ADT duration was positively associated with AA treatment efficacy in progression free survival and overall survival. It can be used as a pre-treatment predictor.

Contemporary molecular tests for prognosis and treatment guidance for castration-resistant prostate cancer

INTRODUCTION

Currently, clinical factors related to the malignancy and patient-related factors such as performance status and comorbidities are employed to select agents to treat metastatic castration resistant prostate cancer (mCRPC). Areas covered: This paper covers emerging molecular panels that may be used in the clinic as prognostic or predictive biomarkers to treat mCRPC. Expert commentary: The expression of androgen receptor variant (AR-V)-7 in circulating tumor cells appears especially promising to select patients for taxane chemotherapy versus androgen inhibitors, abiraterone and enzalutamide. Additionally, the presence of DNA repair alterations such as BRCA alterations are rapidly emerging as a predictive biomarker to develop precision medicine using PARP inhibitors for these patients.

Clinical effect of abiraterone acetate in Korean patients with metastatic castration-resistant prostate cancer according to duration of androgen deprivation therapy

Purpose

Few data are available concerning the clinical outcome of abiraterone acetate treatment in patients with metastatic castration-resistant prostate cancer (mCRPC) in terms of the duration of androgen deprivation therapy (ADT) before diagnosis of CRPC. We investigated the clinical efficacy of abiraterone acetate according to the duration of ADT.

Materials and Methods

We reviewed the medical records of 20 patients with mCRPC who received abiraterone acetate after failure of docetaxel chemotherapy from May 2012 to March 2014 at Seoul National University Bundang Hospital. Clinical factors including prostate-specific antigen (PSA) nadir level, time to PSA nadir, PSA doubling time, PSA response, and modes of progression (PSA, radiologic, clinical) were analyzed. Disease progression was classified according to the Prostate Cancer Working Group 2 criteria.

Results

The mean age and PSA value of the entire cohort were 76.0±7.2 years and 158.8±237.9 ng/mL, respectively. The median follow-up duration was 13.4±6.7 months. There were no statistically significant differences in clinical characteristics between patients who received abiraterone acetate with ADT duration<35 months and those who received abiraterone acetate with ADT duration≥35 months. There were also no significant differences in terms of PSA progression-free survival, radiologic progression-free survival, and clinical progression-free survival between patients with ADT duration<35 months and those with ADT duration ≥35 months.

Conclusions

Although this was a retrospective study with a small sample size, we did not observe any statistically significant differences in the clinical response to abiraterone acetate between mCRPC patients with long ADT duration and those with short ADT duration in terms of disease progression-free survival.

PD-L1 is highly expressed in Enzalutamide resistant prostate cancer

Efficacy of Enzalutamide (ENZ) in castration resistant prostate cancer (CRPC) patients is short-lived. Immunotherapy like T cell checkpoint blockade may improve patient survival. However, when and where checkpoint molecules are expressed in CRPC and whether immune evasion is a mechanism of ENZ resistance remains unclear. Thus, we investigated whether clinically relevant immunotherapy targets, specifically PD-L1/2, PD-1 and CTLA-4, are upregulated in ENZ resistant (ENZR) patients and in a pre-clinical model of ENZ resistance. We show for the first time that patients progressing on ENZ had significantly increased PD-L1/2⁺ dendritic cells (DC) in blood compared to those naïve or responding to treatment, and a high frequency of PD-1⁺T cells. These data supported our pre-clinical results, in which we found significantly increased circulating PD-L1/2⁺ DCs in mice bearing ENZR tumors compared to CRPC, and ENZR tumors expressed significantly increased levels of tumor-intrinsic PD-L1. Importantly, the expression of PD-L1 on ENZR cells, or the ability to modulate PD-L1/2⁺ DC frequency, was unique to ENZR cell lines and xenografts that did not show classical activation of the androgen receptor. Overall, our results suggest that ENZ resistance is associated with the strong expression of anti-PD-1 therapy targets in circulating immune cells both in patients and in a pre-clinical model that is non-AR driven. Further evaluation of the contribution of tumor vs. immune cell PD-L1 expression in progression of CRPC to anti-androgen resistance and the utility of monitoring circulating cell PD-L1 pathway activity in CRPC patients to predict responsiveness to checkpoint immunotherapy, is warranted.

Comparative analysis of the effectiveness of abiraterone before and after docetaxel in patients with metastatic castration-resistant prostate cancer

AIM: To study the efficacy and safety of abiraterone in patients with and without prior chemotherapy.

METHODS: The databases including PubMed and abstracts presented at the American Society of Clinical Oncology meetings up to April 2014 were systematically searched. Eligible studies included randomized controlled trials (RCTs) in which abiraterone plus prednisone was compared to placebo plus prednisone in metastatic castration-resistant prostate cancer (CRPC) patients. The summary incidence, relative risk, hazard ratio and 95%CI were calculated using random or fixed-effects models. Heterogeneity test was performed to test between-study differences in efficacy and toxicity.

RESULTS: A total of two phase III RCTs were included in our analysis, with metastatic CPRC patients before (n = 1088) and after chemotherapy (n = 1195). Prior chemotherapy did not significantly alter the effect of abiraterone on overall survival (P = 0.92) and prostate-specific antigen (PSA) progression-free survival (P = 0.13), but reduced its effect on radiographic-progression-free survival (P = 0.04), objective response rate (P < 0.001), and PSA response rate (P < 0.001). Prior chemotherapy significantly increased the specific risk of fluid retention and edema (P < 0.001) and hypokalemia (P < 0.001), but decreased the risk of all-grade hypertension (P < 0.001) attributable to abiraterone. There was no significant difference of cardiac disorders associated with abiraterone between the two settings (P = 0.58).

CONCLUSION: Prior chemotherapy may reduce the effectiveness of abiraterone in patients with metastatic CRPC.

The diverse chemistry of cytochrome P450 17A1 (P450c17, CYP17A1)

The steroid hydroxylation and carbon-carbon bond cleavage activities of cytochrome P450 17A1 (CYP17A1) are responsible for the production of glucocorticoids and androgens, respectively. The inhibition of androgen synthesis is an important strategy to treat androgen-dependent prostate cancer. We discuss the different enzymatic activities towards the various substrates of CYP17A1, demonstrating its promiscuity. Additionally, a novel interhelical interaction is proposed between the F-G loop and the B'-helix to explain the 16α-hydroxylase activity of human CYP17A1 with progesterone as the substrate. The techniques used by biochemists to study this important enzyme are also summarized. This article is part of a Special Issue entitled 'Steroid/Sterol signaling'.