Improved outcomes in elderly patients with metastatic castration-resistant prostate cancer treated with the androgen receptor inhibitor enzalutamide: results from the phase III AFFIRM trial

Docetaxel Versus Androgen-Receptor Signaling Inhibitors (ARSI) as Second-Line Therapy After Failure of First-Line Alternative ARSI for the Elderly ≥ 75 Years Old With Metastatic Castration-Resistant Prostate Cancer (mCRPC): A SPARTACUSS-Meet-URO 26 Real-World Study

BACKGROUND

Androgen receptor signalling inhibitors (ARSIs) abiraterone acetate (AA) enzalutamide (Enza), are currently the standard first-line (L1) treatments for metastatic castration-resistant prostate cancer (mCRPC), and docetaxel (D) is reserved as second-line (L2) after ARSI failure. Nonetheless, D use in men ≥ 75 years old is restricted owing to treatment toxicities and patient comorbidities, and a L2 alternative ARSI is frequently used. We aimed to evaluate real-life survival and toxicity outcomes of these elderly patients after failure of L1 ARSI treatment.

MATERIAL AND METHODS

We retrospectively evaluated efficacy and safety in a real-world international cohort of consecutive patients ≥ 75 years old when starting L1 ARSI for mCRPC according to the choice of L2 treatment (D versus alternative ARSI).

RESULTS

Of the 122 identified patients, 57 (46.7%) had received L2 ARSI and 65 (53.3%) L2 D. No difference was found in the L1 overall survival (OS) for the ARSI and D groups (32.8 vs. 30.0 months, respectively; Hazard ratio [HR] = 1.22; 95% CI, 0.77-1.95; P = .40) or in the L2 OS (18.5 vs. 17.8 months, respectively; HR = 1.09; 95% CI, 0.69-1.74; P = .71). No difference was observed for rPFS from L2 (P = .12), although a trend was observed for a numerically improved rPFS on D.

CONCLUSION

Within the limitations of a retrospective design and small population, our study suggests that D or ARSI after failure of L1 alternative ARSI are clinically comparable L2 options for elderly patients with mCRPC.

PROTACing the androgen receptor and other emerging therapeutics in prostate cancer

INTRODUCTION

The androgen receptor (AR) is a critical driver of prostate cancer progression, and the advent of androgen receptor pathway inhibitors (ARPIs) has transformed the treatment landscape of metastatic prostate cancer. However, resistance to ARPIs eventually develops via mutations in AR, AR overexpression, and alternative AR signaling which have required novel approaches to target effectively.

AREAS COVERED

The mechanism of action and early clinical results of proteolysis targeting chimera (PROTAC) agents targeting AR are reviewed. Preclinical and early clinical data for other emerging AR-targeting therapeutics, including dual-action androgen receptor inhibitors (DAARIs) and anitens that target the N-terminal domain of AR, were also identified through literature search for agents which may circumvent resistance through AR splice variants and AR ligand-binding domain mutations. The literature search utilized PubMed to identify articles that were relevant to this review from 2000 to 2024.

EXPERT OPINION

PROTACs, DAARIs, and anitens represent novel and promising AR-targeting therapeutics that may become an important part of prostate cancer treatment in the future. Elucidating mechanisms of resistance, including ability of these agents to target full length AR, may yield further insights into maximal therapeutic efficacy aimed at silencing AR signaling.

Clinical Outcomes of Enzalutamide in Metastatic Hormone-sensitive Prostate Cancer in Patients Aged <75 and ≥75 Years: ARCHES Post Hoc Analysis

BACKGROUND

In ARCHES, treatment intensification of androgen deprivation therapy (ADT) with enzalutamide versus placebo improved clinical outcomes in metastatic hormone-sensitive prostate cancer (mHSPC). Understanding the benefits and tolerability of enzalutamide for men aged ≥75 yr may inform disease management.

OBJECTIVE

To determine whether age is associated with clinical outcomes in mHSPC.

DESIGN, SETTING, AND PARTICIPANTS

A post hoc analysis of the multinational, double-blind, randomized, placebo-controlled, phase 3 ARCHES trial in 1150 men with mHSPC (median follow-up [mo]: <75 yr, 44.6; ≥75 yr, 44.3) was performed.

INTERVENTION

Randomization 1:1 to enzalutamide (160 mg/d) plus ADT or placebo plus ADT; stratification by disease volume and prior docetaxel use.

OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS

Overall survival (OS), radiographic progression-free survival (rPFS), safety, and other secondary endpoints were compared between age groups (<75 and ≥75 yr) and treatment arms (Cox proportional hazard models).

RESULTS AND LIMITATIONS

Men aged <75 versus ≥75 yr had longer OS (enzalutamide plus ADT: hazard ratio [HR] 0.66; 95% confidence interval [CI] 0.47-0.91; p = 0.02; placebo plus ADT: HR 0.81; 95% CI 0.60-1.09; p = 0.13) and rPFS (enzalutamide plus ADT: HR 0.78; 95% CI 0.58-1.04; p = 0.12; placebo plus ADT: HR 0.98; 95% CI 0.74-1.30; p = 0.007). Enzalutamide improved OS (<75 yr: HR 0.61; 95% CI 0.47-0.79; ≥75 yr: HR 0.76; 95% CI 0.54-1.09) and secondary efficacy endpoints without evidence of statistical heterogeneity, and was generally well tolerated in both age groups, with minimal quality-of-life impact. Older versus younger patients experienced more frequent dose interruptions (20.2% vs 10.9%) and treatment-emergent adverse events (95.2% vs 89.1%). Post hoc examination and small sample size preclude definitive conclusions.

CONCLUSIONS

Enzalutamide plus ADT improved efficacy outcomes and was generally well tolerated despite shorter treatment exposure in older patients, indicating enzalutamide's utility in patients with mHSPC aged <75 and ≥75 yr.

PATIENT SUMMARY

Enzalutamide is a drug approved to treat men with prostate cancer. In this report, we compared patients aged <75 and ≥75 yr treated with enzalutamide plus androgen deprivation therapy to determine whether age affected how long they lived without the cancer spreading to other parts of their body. We found that, although younger patients had more favorable survival outcomes, enzalutamide was associated with longer survival and reduced disease spread in both age groups.

Enzalutamide: Understanding and Managing Drug Interactions to Improve Patient Safety and Drug Efficacy

Enzalutamide is an oral androgen receptor signaling inhibitor utilized in the treatment of men with prostate cancer. It is a moderate inducer of the cytochrome P450 (CYP) enzymes CYP2C9 and CYP2C19, and a strong inducer of CYP3A4. It was also shown to be a mild inhibitor of the efflux transporter P-glycoprotein in patients with prostate cancer. Enzalutamide is primarily metabolized by CYP3A4 and CYP2C8. The risk of enzalutamide drug interactions arises primarily when it is coadministered with other drugs that interact with these CYPs, including CYP3A4. In this review, we begin by providing an overview of enzalutamide including its dosing, use in special populations, pharmacokinetics, changes to its prescribing information, and potential for interaction with coadministered drugs. Enzalutamide interactions with drugs from a wide range of medication classes commonly prescribed to patients with prostate cancer are described, including oral androgen deprivation therapy, agents used to treat a range of cardiovascular diseases, antidiabetic drugs, antidepressants, anti-seizure medications, common urology medications, analgesics, proton pump inhibitors, immunosuppressants, and antigout drugs. Enzalutamide interactions with common vitamins and supplements are also briefly discussed. This review provides a resource for healthcare practitioners and patients that will help provide a basis for the understanding and management of enzalutamide drug-drug interactions to inform decision making, improve patient safety, and optimize drug efficacy.

Treatment patterns and outcomes in older adults with castration-resistant prostate cancer: Analysis of an Australian real-world cohort

INTRODUCTION

Prostate cancer (PC) is the second commonest malignancy and fifth leading cause of cancer death in men worldwide. Older men are more likely to develop PC but are underrepresented in pivotal clinical trials, leading to challenges in treatment selection in the real-world setting. We aimed to examine treatment patterns and outcomes in older Australians with metastatic castration-resistant prostate cancer (mCRPC).

MATERIALS AND METHODS

We identified 753 men with mCRPC within the electronic CRPC Australian Database (ePAD). Clinical data were analysed retrospectively to assess outcomes including time to treatment failure (TTF), overall survival (OS), PSA doubling time (PSADT), PSA50 response rate, and pre-defined adverse events of special interest (AESIs). Descriptive statistics were used to report baseline characteristics, stratified by age groups (<75y, 75-85y and >85y). Groups were compared using Kruskal-Wallis and Chi-square analyses. Time-to-event analyses were performed using Kaplan-Meier methods and compared through log-rank tests. Cox proportional hazards univariate and multivariate analyses were performed to evaluate the influence of variables on OS.

RESULTS

Fifty-seven percent of men were aged <75y, 31% 75-85y, and 12% >85y. Patients ≥75y more frequently received only one line of systemic therapy (40% of <75y vs 66% 75-85y vs 68% >85y; P < 0.01). With increasing age, patients were more likely to receive androgen receptor signalling inhibitors (ARSIs) as initial therapy (42% of <75y vs 70% of 75-85y vs 84% of >85y; p < 0.01). PSA50 response rates or TTF did not significantly differ between age groups for chemotherapy or ARSIs. Patients >85y receiving enzalutamide had poorer OS but this was not an independent prognostic variable on multivariate analysis (hazard ratio [HR] 0.93(0.09-9.35); p = 0.95). PSADT >3 months was an independent positive prognostic factor for patients receiving any systemic therapy. Older patients who received docetaxel were more likely to experience AESIs (18% in <75y vs 37% 75-85y vs 33% >85y, p = 0.038) and to stop treatment as a result (21% in <75y vs 39% in 75-85y; p = 0.011).

DISCUSSION

In our mCRPC cohort, older men received fewer lines of systemic therapy and were more likely to cease docetaxel due to adverse events. However, treatment outcomes were similar in most subgroups, highlighting the importance of individualised assessment regardless of age.

Feasibility of cabazitaxel in octogenarian prostate cancer patients

Background

To evaluate the effectiveness and safety of cabazitaxel in castration-resistant prostate cancer patients aged ≥80 years, we performed a retrospective study on a sample of patients from 11 Italian cancer centers.

Materials and methods

Fifty-seven patients aged ≥80 years were treated with cabazitaxel after previous failure with docetaxel; 39 completed a comprehensive geriatric assessment questionnaire (34 fit and 5 vulnerable) and 8 patients (14%) had an Eastern Cooperative Oncology Group performance status (PS) ≥2, while most had a PS of 0-1 (86%). Cabazitaxel was administered at a dose of 25 mg/m2 in 30 (52%) patients and 20 mg/m2 or adapted schedules in 27 (48%) patients. These schedules were adopted mainly in patients ≥85 years (75%), with a PS ≥2 (87.5%), and those classified as vulnerable (100%).

Results

The duration of treatment was 4.8 months and was comparable in all subgroups; disease control rate was reported in 36 patients (63%); prostate-specific antigen response was recorded in 18 patients (31.5%). Median overall survival was 13.1 months regardless of age (<85/≥85 years), but overall survival was reduced in vulnerable (7.2 months) and PS ≥ 2 patients (6.8 months). The most frequently documented grade 3-4 toxicities were neutropenia (14%) and diarrhea (10.5%). Six patients (10.5%) dropped out due to severe toxicity.

Conclusions

Octogenarian patients can be treated with cabazitaxel with reduced doses or alternative schedules that are associated with less toxicity and fewer treatment interruptions. Comprehensive geriatric assessment could facilitate more appropriate patient selection.

A national questionnaire survey of Japanese urologists on treatment perspectives for elderly prostate cancer patients

OBJECTIVE

This study conducted a national questionnaire survey of Japanese urologists from a treatment perspective for older patients with prostate cancer.

METHODS

A questionnaire was distributed to 922 teaching hospitals of the Japanese Urological Association. Questionnaire items included years of urologist experience, gender, workplace, treatment equipment owned, daily specialty practice area, urological cancer specialty, treatment reference items for older adults, upper age limit for radical treatment, medication, and two hypothetical cases of Gleason grade group 2 prostate cancer with or without oligometastasis.

RESULTS

In total, 1732 questionnaires were analyzed, with responses evenly distributed across all age groups. Workplaces included general hospitals (49.4%), university hospitals (40.3%), and cancer centers (4.2%). Performance status was the most frequently mentioned treatment-related item, followed by comorbidities and cognitive function. In addition, geriatric assessment was used by only 13.3% of respondents. No upper age limit was found for total prostatectomy, brachytherapy, and external beam radiation. Anti-androgens, androgen receptor-axis-targeted agents, chemotherapy, poly ADP ribose polymerase inhibitors, and immune-checkpoint inhibitors were selected by 6.8%, 35.6%, 47.3%, 89%, 62.8%, 24.7%, 41.9%, and 41.7% of the respondents, respectively. Response rates for administration of hormone therapy for hypothetical cases of Gleason grade group 2 prostate cancer with or without oligometastases were 96.8% and 61.2%, respectively.

CONCLUSIONS

Less than 15% of urologists used geriatric assessments. Several responded that they would set age limits for highly invasive radical and systemic therapies.

Androgen receptor pathway inhibitors, prostate cancer, and older adults: a global Young International Society of Geriatric Oncology drug review

Prostate cancer is a disease of older adults that has undergone a significant therapeutic paradigm shift in the last decade with the emergence of novel androgen receptor pathway inhibitors (ARPis). One of the more commonly used ARPis is enzalutamide. This drug, along with darolutamide and apalutamide, initially received approvals in the metastatic castrate-resistant prostate cancer setting but is now utilized frequently in the metastatic castrate-sensitive and non-metastatic castration-resistant settings. Landmark phase III data illustrating ARPi efficacy in older adults are limited to those with excellent performance status. However, its role in unfit older prostate cancer patients remains to be explored in the context of a narrative review. This first-of-its-kind drug review aims to shed light on the most up-to-date evidence behind the unique toxicity profile of ARPis in the context of geriatric vulnerabilities such as cognitive and functional impairment, along with potential solutions and supporting evidence that exists to circumvent these issues in the vulnerable older adult.

Talazoparib, a Poly(ADP-ribose) Polymerase Inhibitor, for Metastatic Castration-resistant Prostate Cancer and DNA Damage Response Alterations: TALAPRO-1 Safety Analyses

BACKGROUND

The phase II TALAPRO-1 study (NCT03148795) demonstrated durable antitumor activity in men with heavily pretreated metastatic castration-resistant prostate cancer (mCRPC). Here, we detail the safety profile of talazoparib.

PATIENTS AND METHODS

Men received talazoparib 1 mg/day (moderate renal impairment 0.75 mg/day) orally until radiographic progression, unacceptable toxicity, investigator decision, consent withdrawal, or death. Adverse events (AEs) were evaluated: incidence, severity, timing, duration, potential overlap of selected AEs, dose modifications/discontinuations due to AEs, and new clinically significant changes in laboratory values and vital signs.

RESULTS

In the safety population (N = 127; median age 69.0 years), 95.3% (121/127) experienced all-cause treatment-emergent adverse events (TEAEs). Most common were anemia (48.8% [62/127]), nausea (33.1% [42/127]), decreased appetite (28.3% [36/127]), and asthenia (23.6% [30/127]). Nonhematologic TEAEs were generally grades 1 and 2. No grade 5 TEAEs or deaths were treatment-related. Hematologic TEAEs typically occurred during the first 4-5 months of treatment. The median duration of grade 3-4 anemia, neutropenia, and thrombocytopenia was limited to 7-12 days. No grade 4 events of anemia or neutropenia occurred. Neither BRCA status nor alteration origin significantly impacted the safety profile. The median (range) treatment duration was 6.1 (0.4-24.9) months; treatment duration did not impact the incidence of anemia. Only 3 of the 15 (11.8% [15/127]) permanent treatment discontinuations were due to hematologic TEAEs (thrombocytopenia 1.6% [2/127]; leukopenia 0.8% [1/127]).

CONCLUSION

Common TEAEs associated with talazoparib could be managed through dose modifications/supportive care. Demonstrated efficacy and a manageable safety profile support continued evaluation of talazoparib in mCRPC.

CLINICALTRIALS.GOV IDENTIFIER

NCT03148795.

Factors influencing survival in metastatic castration resistant prostate cancer therapy

INTRODUCTION

The number of patients with metastatic castration resistant prostate cancer (mCRPC) is expecting to increase due to the long-life expectancy of those with advanced disease who are also more commonly diagnosed today because of stage migration. Several compounds are available for treating these patients.

AREAS COVERED

We reviewed currently available treatments for mCRPC, their mechanism of action and resistance and we explored possible predictors of treatment success useful to predict survival in mCRPC patients.

EXPERT OPINION

A combination of molecular, clinical, pathological, and imaging features is necessary to correctly estimate patients' risk of death. The combination of these biomarkers may allow clinicians to tailor treatments based on cancer history and patients' features. The search of predictive biomarkers remains an unmet medical need for most patients with mCRPC.

Management of prostate cancer in older patients

The incidence of prostate cancer among older men has increased in many countries, including Asian countries. However, older patients are ineligible for inclusion in large randomized trials, and the existing guidelines for the management of patients with prostate cancer do not provide specific treatment recommendations for older men. Therefore, generation of evidence for older patients with prostate cancer is a key imperative. The International Society of Geriatric Oncology has produced and updated several guidelines for management of prostate cancer in older men since 2010. Regarding localized prostate cancer, both surgery and radiotherapy are considered as feasible treatment options for intermediate- and high-risk prostate cancer even in older men, whereas watchful waiting and active surveillance are useful options for a proportion of these patients. With regard to advanced disease, androgen-receptor axis targets and taxane chemotherapy are standard treatment modalities, although dose modification and prevention of adverse events need to be considered. Management strategy for older patients with prostate cancer should take cognizance of not only the chronological age but also psychological and physical condition, socio-economic status and patient preferences. Geriatric assessment and patient-reported health-related quality of life are important tools for assessing health status of older patients with prostate cancer; however, there is a paucity of evidence of the impact of these tools on the clinical outcomes. Personalized management according to the patient's health status and tumour characteristics as well as socio-economic condition may be necessary for treatment of older patients with prostate cancer.

Consistent survival benefit of enzalutamide plus androgen deprivation therapy in men with nonmetastatic castration-resistant prostate cancer: PROSPER subgroup analysis by age and region

BACKGROUND

Enzalutamide combined with androgen deprivation therapy (ADT) significantly prolonged metastasis-free survival and overall survival (OS) versus ADT alone in patients with non-metastatic castration-resistant prostate cancer (nmCRPC) with rapidly rising prostate-specific antigen (PSA). The objective of this post hoc analysis of the PROSPER trial is to evaluate OS benefit and safety of enzalutamide in patients across age and regional subgroups.

PATIENTS AND METHODS

Eligible men with nmCRPC, PSA doubling time ≤10 months and PSA ≥2 ng/mL with continued ADT use were randomised 2:1 to enzalutamide 160 mg or placebo. OS and safety were examined by age (<70 vs ≥70 years) and region (North America, Europe, Asia or the rest of the world). The impact of prior and subsequent therapy was also examined.

RESULTS

In total, 1401 men were enrolled (median age, 74 years). Enzalutamide plus ADT reduced the risk of death, independent of age or region. Multivariate analyses identified Eastern Cooperative Oncology Group (ECOG) status (P < 0.0001), log (PSA; P = 0.0002) and subsequent therapy (P < 0.0001) as statistically significant factors impacting OS. Safety was consistent across age and regional subgroups. Any grade treatment-emergent adverse events were similar across age groups, were more common in the placebo group and had regional variation.

CONCLUSIONS

In men with nmCRPC and rapidly rising PSA, the benefit and safety of enzalutamide were consistent across age and regional subgroups. Variables impacting OS included ECOG status, log (PSA) and subsequent therapy. CLINICALTRIALS.

GOV IDENTIFIER

NCT02003924.

Androgen Receptor Signaling in Prostate Cancer and Therapeutic Strategies

Understanding of the molecular mechanisms of prostate cancer has led to development of therapeutic strategies targeting androgen receptor (AR). These androgen-receptor signaling inhibitors (ARSI) include androgen synthesis inhibitor-abiraterone and androgen receptor antagonists-enzalutamide, apalutamide, and darolutamide. Although these medications provide significant improvement in survival among men with prostate cancer, drug resistance develops in nearly all patients with time. This could be through androgen-dependent or androgen-independent mechanisms. Even weaker signals and non-canonical steroid ligands can activate AR in the presence of truncated AR-splice variants, AR overexpression, or activating mutations in AR. AR splice variant, AR-V7 is the most studied among these and is not targeted by available ARSIs. Non-androgen receptor dependent resistance mechanisms are mediated by activation of an alternative signaling pathway when AR is inhibited. DNA repair pathway, PI3K/AKT/mTOR pathway, BRAF-MAPK and Wnt signaling pathway and activation by glucocorticoid receptors can restore downstream signaling in prostate cancer by alternative proteins. Multiple clinical trials are underway exploring therapeutic strategies to overcome these resistance mechanisms.

Effectiveness of first-line abiraterone versus enzalutamide among patients ≥80 years of age with metastatic castration-resistant prostate cancer: A retrospective propensity score-weighted comparative cohort study

BACKGROUND

Metastatic castration-resistant prostate cancer (mCRPC) disproportionately affects the elderly. There is limited data assessing the efficacy and tolerability of abiraterone acetate (AA) versus enzalutamide in this population.

OBJECTIVE

To compare the clinical efficacy and tolerability of AA versus enzalutamide in patients ≥ 80 years with mCRPC.

DESIGN, SETTING AND PARTICIPANTS

A retrospective propensity-weighted comparative cohort study of first-line AA versus enzalutamide among patients with mCRPC aged ≥80 years.

OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS

Inverse probability treatment weights based on propensity scores were generated to assess the treatment effect of AA versus enzalutamide on time to PSA progression (TTPP), time to progression (TTP) (first of PSA/radiographic/clinical progression) and overall survival using a weighted Cox proportional hazards model. PSA response rate (PSA RR) was compared between groups using Χ².

RESULTS AND LIMITATIONS

One hundred fifty-three patients received AA, and 125 received enzalutamide. Enzalutamide was associated with higher PSA RR (61.6% vs 43.8%, P < 0.004), and TTP (hazard ratio [HR] 0.66, 95% confidence interval [CI] 0.50-0.88, P = 0.01) but not TTPP (HR 0.73, 95% CI 0.53-1.01, P = 0.06). There were significantly more dose reductions with enzalutamide (22.9% vs 44.8%, P > 0.001) but there was no interaction between median proportion of full dose received and TTPP or TTP for either drug. Rates of treatment discontinuation (for reasons other than progression) were also significantly different between AA and enzalutamide (28.8% vs 40.8%, respectively, P = 0.04). The most common reason for dose reductions and discontinuation of enzalutamide was fatigue (30.4% and 5.6%, respectively).

CONCLUSIONS

Despite more dose reductions and a higher treatment discontinuation rate, enzalutamide was associated with a higher PSA RR and longer time to progression, than AA. Given that clinical outcomes were not adversely impacted by decreased treatment exposure, dose modification may be a useful treatment strategy to balance toxicity and tolerance.

Risk of cardiovascular disease following gonadotropin-releasing hormone agonists vs antagonists in prostate cancer: Real-world evidence from five databases

Observational studies in prostate cancer (PCa) have shown an increased risk of cardiovascular disease (CVD) following gonadotropin-releasing hormone (GnRH) agonists, whereas randomised-controlled trials have shown no associations. Compared to GnRH agonists, GnRH antagonists have shown less atherosclerotic effects in preclinical models. We used real-world data from five countries to investigate CVD risk following GnRH agonists and antagonists in PCa men. Data sources included cancer registries, primary and secondary healthcare databases. CVD event was defined as an incident or fatal CVD. Multivariable Cox proportional hazard models estimated hazard ratios (HRs) and 95% confidence intervals (CIs), which were pooled using random-effects meta-analysis. Stratified analyses were conducted by history of CVD and age (75 years). A total of 48 757 men were on GnRH agonists and 2144 on GnRH antagonists. There was no difference in risk of any CVD for men on GnRH antagonists and agonists (HR: 1.25; 95% CI: 0.96-1.61; I2 : 64%). Men on GnRH antagonists showed increased risk of acute myocardial infarction (HR: 1.62; 95% CI: 1.11-2.35; I2 : 0%) and arrhythmia (HR: 1.55; 95% CI: 1.11-2.15, I2 : 17%) compared to GnRH agonists. Having a history of CVD was found to be an effect modifier for the associations with some CVD subtypes. Overall, we did not observe a difference in risk of overall CVD when comparing GnRH antagonists with agonists-though for some subtypes of CVD we noted an increased risk with antagonists. Further studies are required to address potential confounding caused by unadjusted variables such as severity of CVD history and PCa stage.

Enzalutamide in patients with castration-resistant prostate cancer: retrospective, multicenter, real life study

BACKGROUND

Metastatic castration-resistant prostate cancer (mCRPC) is the final stage of pCa history and represents a clinically relevant phenotype with an elevated burden of mortality. The aim of the present study was to evaluate the efficacy and safety of enzalutamide in a "real-life" setting in mCRPC patients.

METHODS

Data about all mCRPC patients treated with enzalutamide from September 2017 to September 2018 were collected. Demographics, comorbidities, clinical parameters, outcomes, toxicity, overall survival and progression free survival were analyzed.

RESULTS

Overall, 158 patients were enrolled. Mean age was 75.8 (±8.7) years with a baseline median PSA of 16.5 (IQR 7.4-47.8) ng/mL. The median follow-up lasted 7.7 (IQR 4-14.1) months. Of all the 10.1% of patients reported grade 3-4 adverse events. 43.7% of patients experienced a progression. Overall, the 6 and 12 months PFS rates were 69.5% (95% CI: 61.7-78.3%) and the 45.6% (95% CI: 36.5-57.1%); a median baseline PSA>16 ng/mL (HR:2.0, 95% CI: 1.2-3.3, P<0.005), the use of opioid (HR: 3.1, 95% CI: 1.9-5.0, P<0.001), a previous treatment (abiraterone, docetaxel or abiraterone + docetaxel) were significantly associated with higher rates of cancer progression. Conversely, a brief pain questionnaire of 0-1 (HR: 0.4, 95% CI: 0.2-0.7, P<0.001), a 12 weeks 50% PSA reduction (HR: 0.4, 95% CI: 0.2-0.8, P<0.006) and a longer time to mCRPC (HR: 0.4, 95% CI: 0.3-0.7, P<0.002) were related to lower cancer progression rates.

CONCLUSIONS

Our data shows an effective and safe profile of enzalutamide in a "real world" perspective in patients with mcRPC.

Rapamycin inhibits AR signaling pathway in prostate cancer by interacting with the FK1 domain of FKBP51

Reactivation of the androgen receptor signaling pathway in the emasculated environment is the main reason for the occurrence of castration-resistant prostate cancer (CRPC). The immunophilin FKBP51, as a co-chaperone protein, together with Hsp90 help the correct folding of AR. Rapamycin is a known small-molecule inhibitor of FKBP51, but its effect on the FKBP51/AR signaling pathway is not clear. In this study, the interaction mechanism between FKBP51 and rapamycin was investigated using steady-state fluorescence quenching, X-ray crystallization, MTT assay, and qRT-PCR. Steady-state fluorescence quenching assay showed that rapamycin could interact with FKBP51. The crystal of the rapamycin-FKBP51 complex indicated that rapamycin occupies the hydrophobic binding pocket of FK1 domain which is vital for AR activity. The residues involving rapamycin binding are mainly hydrophobic and may overlap with the AR interaction site. Further assays showed that rapamycin could inhibit the androgen-dependent growth of human prostate cancer cells by down-regulating the expression levels of AR activated downstream genes. Taken together, our study demonstrates that rapamycin suppresses AR signaling pathway by interfering with the interaction between AR and FKBP51. The results of this study not only can provide useful information about the interaction mechanism between rapamycin and FKBP51, but also can provide new clues for the treatment of prostate cancer and castration-resistant prostate cancer.

•

Rapamycin occupies the hydrophobic binding pocket of FK1 domain of FKBP51.

•

Rapamycin suppresses the AR signaling pathway by interacting with FKBP51.

•

Rapamycin inhibits the growth of prostate cancer cells via the AR signaling pathway.

Risk Assessment and Considerations for Proper Management of Elderly Men with Advanced Prostate Cancer: A Systematic Review

CONTEXT

Treatment decisions for elderly men with prostate cancer are complicated by the intersection of competing risks of cancer, potential complications of treatment, and individual patients' comorbidities.

OBJECTIVE

To perform a systematic review of data guiding the assessment of elderly prostate cancer patients that addresses the risk from cancer and treatment, and to discuss a patient-centered approach to incorporating these factors into decision making.

EVIDENCE ACQUISITION

Evidence was gathered via a systematic review of the current literature. The search strategy used the terms prostate cancer, elderly, geriatric, >75 yr of age, risk assessment, and treatment in several combinations, and was limited to phase ≥ II clinical trials published between January 2008 and November 2018. Additional supporting literature for the discussion was pulled by hand search.

EVIDENCE SYNTHESIS

The benefits of treatment identified for systemic therapies commonly used to treat men with prostate in general extend to elderly patients. Evidence supports a multifaceted assessment of the risks of cancer and aging, and an understanding of the side effects of treatment to optimally guide therapeutic decision making for elderly patients. There is little evidence defining a geriatric risk stratification system specific to prostate cancer, and recommendations are predominantly based on adapted geriatric oncology approaches and expert consensus.

CONCLUSIONS

The care of elderly men with prostate cancer should incorporate a review of cancer risk, an assessment of aging, and an understanding of the effects of treatment to provide the patient with thorough and personalized guidance for treatment decisions. Future studies of elderly men with prostate cancer can define and validate ideal risk stratification methods as well as management approaches that may be distinct from those for younger populations.

PATIENT SUMMARY

Treatment decisions for elderly men with prostate cancer require consideration of the risk posed by the cancer coupled with an understanding of the patient's general health status.

Abiraterone acetate plus Prednisone/Prednisolone compared with Enzalutamide in metastatic castration resistant prostate cancer before or after chemotherapy: A retrospective study of real‐world data (ACES)

Background

Abiraterone acetate combined with Prednisone/Prednisolone (AA+P) and Enzalutamide (ENZ) have proven survival benefit in men with metastatic castration‐resistant prostate cancer (mCRPC) in chemotherapy‐naïve and prior chemotherapy patients. There have been no studies directly comparing the effectiveness of ENZ to AA+P in mCRPC patients.

Methods

A retrospective, survival analysis study of 143 real‐world mCRPC patients (90 in AA+P and 53 in ENZ group) was conducted. Patients who started their treatment between February 2012 and May 2016 were included. The primary end point was biochemical progression‐free survival (bPFS). Secondary end points were radiological progression‐free survival (rPFS) and overall survival (OS). Toxicity data were also collected. Data were analyzed using Cox proportional hazards (PH) models, adjusting for covariates: prior radical treatment; Gleason score; prostate‐specific antigen; age; and chemotherapy naïve or not.

Results

After median follow‐up of 15 months (interquartile range 7 to 23), 112 events of biochemical progression were observed (71 in AA+P and 41 in ENZ). About 41% in AA+P group and 30% patients in ENZ group received prior chemotherapy. The chance of biochemical progression was significantly lower among ENZ patients than AA+P patients, when adjusting for all covariates in the Cox PH model (hazard ratio [HR] 0.54, 95% confidence interval [CI] 0.35 to 0.82, P = .004). There was a trend implying the chance of rPFS could be higher among ENZ patients than AA+P patients (HR 1.24, 95% CI 0.76 to 2.02, P = .4). There is no difference in OS between ENZ and AA+P patients, when adjusting for all covariates in the Cox PH model (HR 0.91, 95% CI 0.59 to 1.41, P = .7). About 38% of ENZ patients reported fatigue compared to 16% of AA+P patients, while hypertension was reported slightly more in AA+P patients.

Conclusions

This study showed a statistically significant difference in bPFS, favoring ENZ, but no significant difference in rPFS or OS.

Cancer transcriptomic profiling from rapidly enriched circulating tumor cells

Transcriptomic profiling of metastatic cancer can illuminate mechanisms of progression and lead to new therapies, but standard biopsy is invasive and reflects only a single metastatic site. In contrast, circulating tumor cell (CTC) profiling is noninvasive and repeatable, reflecting the dynamic and systemic nature of advanced disease. To date, transcriptomic profiling of CTCs has not delivered on its full potential, because white blood cells (WBCs) vastly outnumber CTCs. Current profiling strategies either lack cancer sensitivity and specificity or require specialized CTC capture protocols that are not readily scalable to large patient cohorts. Here, we describe a new strategy for rapid CTC enrichment and transcriptomic profiling using commercially available WBC depletion, microfluidic enrichment and RNA sequencing. When applied to blood samples from patients with advanced prostate cancer (PC), transcriptomes from enriched samples cluster with cancer positive controls and previously undetectable prostate-specific transcripts become readily measurable. Gene set enrichment analysis reveals multiple significantly enriched signaling pathways associated with PC, as well as novel pathways that merit further study. This accessible and scalable approach yields cancer-specific transcriptomic data and can be applied repeatedly and noninvasively in large cancer patient cohorts to discover new therapeutic targets in advanced disease.

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

INTRODUCTION

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

OBJECTIVE

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

MATERIALS AND METHODS

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

RESULTS

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

CONCLUSIONS

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

Efficacy and Safety of Non-Steroidal Anti-Androgens in Patients with Metastatic Prostate Cancer: Meta-Analysis of Randomized Controlled Trials

BACKGROUND

Prostate cancer (PCa) is the sixth primary cause of cancer death. However, conflicts are present about the efficacy and safety of Non-steroidal anti-androgens (NSAA) for its treatment. The aim of this study was to assess the efficacy and safety of NSAAs versus any comparator for the treatment of advanced or metastatic PCa (mPCa).

METHODS

MEDLINE and the Cochrane Library were searched. References of included studies and clinicaltrials.gov were also searched for relevant studies. Only English language studies after 1990 were considered for review. Randomized controlled trials (RCTs) examining the efficacy and safety of NSAAs as compared with any other comparator including surgery or chemotherapy in mPCa patients were included. The outcomes include efficacy, safety and the tolerability of the treatment. The Cochrane Risk of Bias Assessment Tool was used for quality assessment. Two authors were independently involved in the selection, extraction and quality assessment of included studies and disagreements were resolved by discussion or by consulting a third reviewer.

RESULTS

Fifty-eight out of 1307 non-duplicate RCTs with 29154 patients were considered for the review. NSAA showed significantly better progression-free survival [PFS] (Hazard ratio [HR], 0.60; 95% confidence interval [CI], 0.46-0.78; P=0.0001), time to distant metastasis or death [TTD] (HR, 0.80; 95% CI 0.73-0.91; P<0.0001), objective response (Odds ratio [OR], 1.64; 95% CI 1.06-2.54; P=0.03) and clinical benefits (OR, 1.33; 95% CI 1.08-1.63; P=0.006) as compared to the control group. There was no significant difference observed between the groups in terms of overall survival (HR, 0.95; 95%CI, 0.87-1.03; P=0.18) and time to progression (HR, 0.93; 95% CI 0.77-1.11; P=0.43). Treatment-related adverse events were more with the NSAA group, but the discontinuation due to lack of efficacy reason was 43% significantly lesser than the control group in patients with mPCa. Rest of the outcomes were appeared to be non-significant.

CONCLUSION

Treatment with NSAA was appeared to be better efficacious with respect to PFS, TTD, and response rate with considerable adverse events when compared to the control group in patients with metastatic PCa.

[Geriatric specificities of prostate cancer]

PURPOSE

To describe the epidemiology of prostate cancer (PCa) and its natural history in the elderly patient. To propose adaptations of geriatric evaluation specific to PCa. Recall therapeutic options and the treatment options specific to elderly patients.

METHOD

Bibliographic research from the Medline bibliographic database (NLM Pubmed tool) and Embase, as well as on the websites of scientific societies of geriatrics, from the National Cancer Institute using the following keywords: elderly, geriatrics, prostate cancer, diagnosis, treatment.

RESULTS

The median age at diagnosis for PCa is 69 years old, making PCa the very type of cancer of the elderly. The specific mortality of the disease increases with age. This translates two of its characteristics. First, a diagnosis at higher grade and stage is more common in older patients than in younger patients. Secondly, use of curative therapeutic options is less common in elderly patients than in younger patients. SIOG recommends a specific geriatric assessment for patients with PCa, which may be useful, but the need for an initial detection of cognitive disorders is open to criticism. There is no therapeutic trial, if only prospective, dedicated to elderly patients with PCa. However, decision-making in the elderly patient with PCa must pursue two goals: first, the respect of the expectations specific to each patient and secondly, the search for the global clinical benefit; goals that should not be restricted to elderly patients.

CONCLUSION

PCa in the elderly patient follow the current guidelines for diagnostic and for treatment. Compliance with these guidelines should eliminate both the late diagnosis and the under-treatment actually observed.

Discovery and development of ODM-204: A Novel nonsteroidal compound for the treatment of castration-resistant prostate cancer by blocking the androgen receptor and inhibiting CYP17A1

We report the discovery of a novel nonsteroidal dual-action compound, ODM-204, that holds promise for treating patients with castration-resistant prostate cancer (CRPC), an advanced form of prostate cancer characterised by high androgen receptor (AR) expression and persistent activation of the AR signaling axis by residual tissue androgens. For ODM-204, has a dual mechanism of action. The compound is anticipated to efficiently dampen androgenic stimuli in the body by inhibiting CYP17A1, the prerequisite enzyme for the formation of dihydrotestosterone (DHT) and testosterone (T), and by blocking AR with high affinity and specificity. In our study, ODM-204 inhibited the proliferation of androgen-dependent VCaP and LNCaP cells in vitro and reduced significantly tumour growth in a murine VCaP xenograft model in vivo. Intriguingly, after a single oral dose of 10-30 mg/kg, ODM-204 dose-dependently inhibited adrenal and testicular steroid production in sexually mature male cynomolgus monkeys. Similar results were obtained in human chorionic gonadotropin-treated male rats. In rats, leuprolide acetate-mediated (LHRH agonist) suppression of the circulating testosterone levels and decrease in weights of androgen-sensitive organs was significantly and dose-dependently potentiated by the co-administration of ODM-204. ODM-204 was well tolerated in both rodents and primates. Based on our data, ODM-204 could provide an effective therapeutic option for men with CRPC.

Enzalutamide: A Review in Castration-Resistant Prostate Cancer

Oral enzalutamide (Xtandi^®), a second generation androgen receptor inhibitor, is indicated for the treatment of castration-resistant prostate cancer (CRPC) in numerous countries worldwide, with specific indications in this patient population varying between individual countries. Based on extensive experience in the clinical trial and/or real-world settings, oral enzalutamide 160 mg once daily is an effective and generally well tolerated treatment in a broad spectrum of patients with CRPC, including in nonmetastatic and metastatic disease and in chemotherapy-naive and -experienced metastatic CRPC. Enzalutamide is an emerging option for the treatment of men with nonmetastatic CRPC who are at high-risk for developing metastatic disease, and remains an important first-line option in chemotherapy-naive or -experienced patients with metastatic CRPC.

HTA and innovative treatments evaluation: the case of metastatic castration-resistant prostate cancer

Purpose: To investigate the implications of the introduction of two hormonal therapies, abiraterone acetate + prednisone (AA+P) and enzalutamide (ENZA), for the treatment of naïve patients with metastatic castration-resistant prostate cancer (mCRPC) in the Italian setting.

Methods: In 2017–2018, a Health Technology Assessment was conducted in Italy, considering the National Healthcare Service (NHS) perspective. Data were retrieved from literature evidence, economic evaluations, and qualitative questionnaires, considering the 9 EUnetHTA dimensions, and a final multi-criteria approach.

Results: On the basis of mCRPC prevalence and incidence rates in Italy, the analysis considered 11,212 males eligible to either AA+P or ENZA treatments. Both drugs led to an improvement of the patients' overall survival, with respect to the standard of care, composed of docetaxel chemotherapy. However, AA+P showed a higher rate of drug-related moderate adverse events and a monitoring activities incidence superior to ENZA (+70%, p-value=0.00), which led to a major resources absorption (€ 1,056.02 vs € 316.25, p-value=0.00), whereas ENZA showed a better cost-effectiveness average value (CEV: 54,586.12 vs 57,624.15). Economic savings ranging from 1.46% to 1.61% emerged for the NHS, as well as organizational advantages, with fewer minutes required for the mCRPC management (AA+P: 815 mins vs ENZA: 500 mins). According to experts’ perceptions, based on a 7-item Likert scale (ranging from −3 to +3), similar results emerged on ethical and social impact (ENZA: 1.35 vs AA+P: 1.48, p-value>0.05), and on legal dimension (ENZA: 0.67 vs AA+P: 0.67, p-value>0.05), since both drugs improved the patients’ quality of life and received approval for use. High-level perceptions related to ENZA adoption emerged with regard to equity (ENZA: 0.69 vs AA+P: 0.25, p-value<0.05), since it is cortisone-free. Multi-criteria approach analysis highlighted a higher score of ENZA than comparator (0.79 vs 0.60, p-value=0.00).

Conclusion: The evidence-based information underlined the advantages of ENZA and AA+P treatments as therapeutic options for mCRPC patients. In the appraisal phase, the higher score than the comparator suggested ENZA as the preferred treatment for mCRPC.

Enzalutamide, an oral androgen receptor inhibitor for treatment of castration-resistant prostate cancer

Androgen receptor (AR) signaling is a key pathway in prostate cancer, and patients are initially treated with androgen deprivation therapy. Patients who have stopped responding to androgen deprivation therapy are considered to have castration-resistant prostate cancer (CRPC), which is still dependent on AR signaling. Enzalutamide, an orally available AR inhibitor, was initially approved by the US FDA for the treatment of patients with metastatic CRPC who have previously received docetaxel. The indication was subsequently extended to include all patients with metastatic CRPC, and most recently to include patients with nonmetastatic CRPC. This review summarizes the body of evidence supporting enzalutamide efficacy and safety in CRPC.

Influence of Age and the Gleason Score in the Choice of Novel Hormonal Therapies Before and After Chemotherapy

BACKGROUND

Novel hormonal therapies (NHTs) have enriched the therapeutic armamentarium available for patients with castration-resistant prostate cancer. However, there is a need for clinical indicators able to drive treatment decisions and timing. The aim of this report is to perform a pooled analysis based on all available literature focused on prediction of efficacy and survival in patients treated with NHTs before and postchemotherapy.

METHODS

After reviewing the studies included in this work, the efficacy and the survival of NHTs according to age and Gleason score (GS) was focused.

RESULTS

A total of eight studies were included in the analysis. With regard to age, the survival hazard ratio shows a better outcome, for both elderly and young patients, in postchemotherapy studies. With regard to progression-free survival, the subgroup analysis of pre- and postchemotherapy studies demonstrates the effect of NHTs on the reduction of risk of progression is greater in prechemotherapy studies irrespective of age. With regard to GS, NHTs show higher efficacy when administered postchemotherapy in patients with GS <8, whereas in patients with GS ≥8 NHTs are more effective in the prechemotherapy setting.

CONCLUSION

Given the limitations of a meta-analysis of data from the literature, the results show that progression-free survival is always higher when NHTs are administered prechemotherapy in comparison with postchemotherapy. This benefit, however, translates in a reduction of risk of death only in patients with GS ≥8. In the other patients, the risk of death decreases when NHTs are administered postchemotherapy.

Current therapeutic options in metastatic castration-resistant prostate cancer

BACKGROUND

The tumors of many patients with prostate cancer eventually become refractory to androgen deprivation therapy with progression to metastatic castration-resistant disease. Significant advances in the treatment of metastatic castration-resistant prostate cancer (mCRPC) have been made in recent years, and new treatment strategies have recently been made available. The aim of this report was to schematically review all the approved pharmacologic treatment options for patients with mCRPC through 2018, analyzing the efficacy and possible side effects of each therapy to assist clinicians in reaching an appropriate treatment decision. New biomarkers potentially of aid in the choice of treatment in this setting are also briefly reviewed.

METHODS

We performed a literature search of clinical trials of new drugs and treatments for patients diagnosed with mCRPC published through 2018.

RESULTS

Two new hormonal drugs, abiraterone acetate and enzalutamide have been approved by FDA in 2011 and 2012, respectively for the treatment of patients with mCRPC and have undergone extensive testing. While these treatments have shown a benefit in progression-free and overall survival, the appropriate sequencing must still be determined so that treatment decisions can be made based on their specific clinical profile. Cabazitaxel has been shown to be an efficient therapeutic option in a postdocetaxel setting, while its role in chemotherapy-naïve patients must still be determined. Sipuleucel-T and radium-223 have been studied in patients without visceral metastases and have achieved overall survival benefits with good safety profiles. The feasibility and efficacy of combinations of new treatments with other known therapies such as chemotherapy are currently under investigation.

CONCLUSIONS

Drug development efforts continue to attempt to prolong survival and improve quality of life in the mCRPC setting, with several therapeutic options available. Ongoing and future trials are needed to further assess the efficacy and safety of these new drugs and their interactions, along with the most appropriate sequencing.

An evaluation method of risk grades for prostate cancer using similarity measure of cubic hesitant fuzzy sets

Prostate cancer (PC) is more common cancer in older men. Then, the existing evaluation method of PC risk grades is based on the AJCC (American Joint Committee on Cancer) staging/scoring system. It utilizes the comprehensive risk data of the prostate-specific antigen (PSA) test, Gleason score, and T₂ staging score as the evaluation criteria of PC patients. However, these risk data of PC patients not only may belong to different risk grades simultaneously to result in the unreasonable and uncertain evaluation results to some extent, but also may lose useful fuzzy and uncertain information in the existing evaluation method with non-fuzzy information. To overcome these insufficiencies, the research problems in this study are: (a) to present a new concept of a cubic hesitant fuzzy set (CHFS) for expressing uncertain and hesitant fuzzy information; (b) to propose the generalized distance and similarity measure between CHFSs; (c) to establish a comprehensive evaluation method of PC risk grades with CHFS information by using the similarity measure of CHFSs; and (d) to provide the evaluation examples of PC patients as actual clinical cases for indicating the rationality and effectiveness of the proposed risk evaluation method. Then, the main contribution of this original study is that we present a new concept of CHFS to express uncertain and hesitant information of PC risk grades and the generalized distance-based similarity measure of CHFSs to establish a comprehensive evaluation method of PC risk grades. Finally, by the 16 evaluation examples of the PC patients, all their evaluation results verify the rationality and effectiveness of the proposed comprehensive evaluation method. The comparative analysis demonstrates that its evaluation performance is superior to that of the existing evaluation method of PC risk grades.

Impact of age on exposure to oral antiandrogen therapies in clinical practice

BACKGROUND

Oral antiandrogen therapies are predominantly used in older men, but real-life studies evaluating the impact of age on pharmacokinetic exposure are lacking. This study aims to evaluate the impact of age on the pharmacokinetic profiles of abiraterone acetate and enzalutamide in clinical practice.

PATIENTS AND METHODS

Retrospective observational study to evaluate the impact of age on the first steady-state sample of patients treated with abiraterone acetate or enzalutamide in routine daily clinical practice. The effect of age on target attainment was assessed.

RESULTS

For abiraterone acetate and enzalutamide, 71 and 64 patients were included, respectively. Baseline patients' characteristics and administered doses were not age-dependent. No age-related differences were observed in exposure to the main metabolites of abiraterone acetate, except for active metabolite Δ(4)-Abiraterone (D4A) with a median plasma concentration of 2.5 × 10^-3 mg/L in the oldest versus 1.3 × 10^-3 mg/L in the youngest age quartile (coefficient of variation, CV, 72%, p = 0.03). For enzalutamide, no significant differences in exposure were found, except for carboxylic acid enzalutamide, having a median plasma concentration of 5.8 mg/L versus 3.9 mg/L in the oldest versus the youngest age quartile (CV 66%, p = 0.03). However, this was driven by one patient aged 99 years old. Age had no significant influence on target attainment of either compound.

CONCLUSIONS

This study showed no significant impact of age on the pharmacokinetic profiles of abiraterone acetate and enzalutamide, except for the active metabolite D4A and the inactive metabolite carboxylic acid enzalutamide, both having significantly higher exposure in older males. Target attainments of abiraterone and enzalutamide were not significantly affected by age, which suggests that age has no clinically relevant impact on exposure to these oral antiandrogen therapies. However, the clinical impact of higher exposure to D4A in older males remains undetermined.

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.

Alterations of androgen receptor-regulated enhancer RNAs (eRNAs) contribute to enzalutamide resistance in castration-resistant prostate cancer

Enzalutamide is a second-generation anti-androgen for treatment of castration-resistant prostate cancer (CPRC). It prolongs survival of CRPC patients, but its overall survival benefit is relatively modest (4.8 months) and by 24 months most patients progress on enzalutamide. To date, however, the molecular mechanisms underlying enzalutamide resistance remain elusive. Herein, we report enzalutamide treatment-induced alterations of androgen receptor (AR)-regulated enhancer RNAs (AR-eRNAs) and their roles in enzalutamide-resistant growth and survival of CRPC cells. AR chromatin immunoprecipitation and high throughput sequencing (ChIP-seq) and RNA-seq analyses revealed that 188 and 227 AR-eRNAs were differentially expressed in enzalutamide-resistant LNCaP and C4-2 cells, respectively. The AR-eRNAs upregulated in C4-2 cells and downregulated in LNCaP cells were selected through meta-analysis. Expression of AR-eRNAs and related mRNAs in the loci of FTO, LUZP2, MARC1 and NCAM2 were further verified by real-time RT-PCR. Silencing of LUZP2 inhibited, but silencing of MARC1 increased the growth of enzalutamide-resistant C4-2 cells. Intriguingly, meta-analysis showed that expression of LUZP2 mRNA increased in primary tumors compared to normal prostate tissues, but decreased again in metastatic CRPC. Our findings suggest that eRNA alteration profiling is a viable new approach to identify functional gene loci that may not only contribute to enzalutamide-resistant growth of CRPC, but also serve as new targets for CRPC therapy.

Pharmacokinetic/pharmacodynamic drug evaluation of enzalutamide for treating prostate cancer

INTRODUCTION

Enzalutamide is the first approved second-generation androgen receptor (AR) antagonist in the treatment of metastatic castration-resistant prostate cancer (mCRPC) with or without docetaxel-based chemotherapy. Over the past 5 years, a number of attempts were made to determine the efficacy of enzalutamide in the different clinical settings. Areas covered: A literature search was performed at the PubMed, Embase, and Web of Science database to collect the most relevant and impactful studies, including basic science investigations, clinical trials, and reviews. This article focuses on the pharmacology, efficacy, tolerability, and future perspective of enzalutamide. Expert opinion: The treatment paradigm of CRPC has been dramatically challenged of late. Enzalutamide are in wide use because of its favorable efficacy and safety, but primary or acquired resistance to the drug will eventually develop. Further studies are thus necessary to identify appropriate patients who can achieve apparent benefits from enzalutamide alone or in combination with other drugs.

Second-line therapy in patients with metastatic castration-resistant prostate cancer with progression after or under docetaxel: A systematic review of nine randomized controlled trials

Treatment decisions are challenging in patients with metastatic castration-resistant prostate cancer with progression after or under docetaxel. The current review systematically searched the published literature on all treatment options, and assessed the risk of bias and quality of evidence. It found the best available evidence for effective prolongation of overall survival and progression-free survival for abiraterone acetate plus prednisone versus placebo plus prednisone and enzalutamide versus placebo. Other treatment modalities could be beneficial for individual patients by taking into consideration the: selection criteria of the randomized clinical trials, risk of bias, subgroup analyses, and quality of life and adverse events. Further research is needed to determine the sequence, timing asnd combination of different treatments.

Efficacy and Safety of Enzalutamide vs Bicalutamide in Younger and Older Patients with Metastatic Castration Resistant Prostate Cancer in the TERRAIN Trial

PURPOSE

Enzalutamide significantly prolonged median progression-free survival vs bicalutamide in chemotherapy naïve men with metastatic castration resistant prostate cancer in the TERRAIN (Enzalutamide versus Bicalutamide in Castrate Men with Metastatic Prostate Cancer) trial. In this post hoc analysis we investigated the influence of age on the efficacy and safety of enzalutamide vs bicalutamide in this population.

MATERIALS AND METHODS

Patients were randomized 1:1 to enzalutamide 160 mg per day or bicalutamide 50 mg per day. Progression-free survival, time to prostate specific antigen progression and safety were analyzed post hoc in younger (age less than 75 years) and older (age 75 years or greater) subgroups.

RESULTS

Enzalutamide significantly reduced the risk of disease progression or death vs bicalutamide in patients younger than 75 years (HR 0.38, 95% CI 0.27-0.52, p <0.0001) and 75 years old or older (HR 0.59, 95% CI 0.37-0.92, p = 0.018). Time to prostate specific antigen progression was also significantly prolonged with enzalutamide vs bicalutamide in each subgroup. The adverse event distribution between treatments was similar in each subgroup except for more (5% or greater difference between subgroups) atrial fibrillation, urinary tract infections, falls and decreased appetite as well as less extremity pain and hot flushing in enzalutamide treated patients 75 years old or older, and less back pain and hot flushing in bicalutamide treated patients 75 years old or older. Grade 3 or greater cardiac events were more frequent in enzalutamide treated and bicalutamide treated patients who were 75 years old or older vs younger than 75 years. Fatigue was more frequent in enzalutamide treated patients with a similar distribution in each age subgroup.

CONCLUSIONS

Enzalutamide improved clinical outcomes vs bicalutamide irrespective of age. Increased falls and cardiac events suggest caution when prescribing to older patients (age 75 years or greater) with significant comorbidity.

Dose considerations for anti-cancer drugs in metastatic prostate cancer

Despite a growing number of treatment options, metastatic castrate resistant prostate cancer remains almost universally fatal. Dose individualization ensures patients receive the maximal benefit from each line of treatment potentially leading to improved outcomes, a reduction in quality of life impairment and minimization of premature cessation for avoidable toxicity. Herein, we review drug-specific issues that may be associated with unexpected or unrecognized variations in drug systemic exposure despite the use of protocol doses. In particular, we discuss the potential for under-exposure of docetaxel and cabazitaxel; over-exposure of enzalutamide; and varied absorption of abiraterone acetate.

Treatment of Metastatic Prostate Cancer in Older Adults

The aging of the population, along with rising life expectancy, means that increasing numbers of older men will be diagnosed with prostate cancer, and a large proportion of these men will present with metastatic disease. In this paper, we discuss recent advances in prostate cancer treatment. In particular, we review management approaches for older patients with metastatic prostate cancer based on the decision tree developed by the International Society of Geriatric Oncology, which categorized older men as "fit," "vulnerable," and "frail" according to comprehensive geriatric assessment.

Indirect comparison between abiraterone acetate and enzalutamide for the treatment of metastatic castration-resistant prostate cancer: a systematic review

This study was designed to evaluate the efficacy, tolerability, and sequential administration of abiraterone acetate (AA) and enzalutamide (Enz) for metastatic castration-resistant prostate cancer (mCRPC). A literature search was performed with PubMed, Embase, and Web of Science databases to identify relevant studies. Reviewed literature included published phase III trials of AA or Enz in mCRPC and studies regarding their sequential administration. Given the difference in control arms in AA (active comparator) and Enz (true placebo) randomized phase III studies, indirect comparisons between AA and Enz in mCRPC showed no statistically significant difference in overall survival in prechemotherapy and postchemotherapy settings (HR: 0.90, 95% CI, 0.73-1.11; HR: 0.85, 95% CI, 0.68-1.07). Compared with AA, Enz may better outperform control arms in treating mCRPC both before and after chemotherapy regarding secondary endpoints based on indirect comparisons: time to prostate-specific antigen (PSA) progression (HR: 0.34, 95% CI, 0.28-0.42; HR: 0.40, 95% CI, 0.30-0.53), radiographic progression-free survival (HR: 0.37, 95% CI, 0.28-0.48; HR: 0.61, 95% CI, 0.50-0.74), and PSA response rate (OR: 18.29, 95% CI, 11.20-29.88; OR: 10.69, 95% CI, 3.92-29.20). With regard to the effectiveness of Enz following AA or AA following Enz, recent retrospective case series reported overall survival and secondary endpoints for patients with mCRPC progression after chemotherapy. However, confirmatory head-to-head trials are necessary to determine the optimal sequencing of these agents.

Dissecting major signaling pathways in prostate cancer development and progression: Mechanisms and novel therapeutic targets

Prostate cancer (PCa) is the most frequently diagnosed non-cutaneous malignancy and leading cause of cancer mortality in men. At the initial stages, prostate cancer is dependent upon androgens for their growth and hence effectively combated by androgen deprivation therapy (ADT). However, most patients eventually recur with an androgen deprivation-resistant phenotype, referred to as castration-resistant prostate cancer (CRPC), a more aggressive form for which there is no effective therapy presently available. The current review is an attempt to cover and establish an understanding of some major signaling pathways implicated in prostate cancer development and castration-resistance, besides addressing therapeutic strategies that targets the key signaling mechanisms.

Management of Prostate Cancer in Elderly Patients: Recommendations of a Task Force of the International Society of Geriatric Oncology

CONTEXT

Prostate cancer is the most frequent male cancer. Since the median age of diagnosis is 66 yr, many patients require both geriatric and urologic evaluation if treatment is to be tailored to individual circumstances including comorbidities and frailty.

OBJECTIVE

To update the 2014 International Society of Geriatric Oncology (SIOG) guidelines on prostate cancer in men aged >70 yr. The update includes new material on health status evaluation and the treatment of localised, advanced, and castrate-resistant disease.

DATA ACQUISITION

A multidisciplinary SIOG task force reviewed pertinent articles published during 2013-2016 using search terms relevant to prostate cancer, the elderly, geriatric evaluation, local treatments, and castration-refractory/resistant disease. Each member of the group proposed modifications to the previous guidelines. These were collated and circulated. The final manuscript reflects the expert consensus.

DATA SYNTHESIS

Elderly patients should be managed according to their individual health status and not according to age. Fit elderly patients should receive the same treatment as younger patients on the basis of international recommendations. At the initial evaluation, screening for cognitive impairment is mandatory to establish patient competence in making decisions. Initial evaluation of health status should use the validated G8 screening tool. Abnormal scores on the G8 should lead to a simplified geriatric assessment that evaluates comorbid conditions (using the Cumulative Illness Score Rating-Geriatrics scale), dependence (Activities of Daily Living) and nutritional status (via estimation of weight loss). When patients are frail or disabled or have severe comorbidities, a comprehensive geriatric assessment is needed. This may suggest additional geriatric interventions.

CONCLUSIONS

Advances in geriatric evaluation and treatments for localised and advanced disease are contributing to more appropriate management of elderly patients with prostate cancer. A better understanding of the role of active surveillance for less aggressive disease is also contributing to the individualisation of care.

PATIENT SUMMARY

Many men with prostate cancer are elderly. In the physically fit, treatment should be the same as in younger patients. However, some elderly prostate cancer patients are frail and have other medical problems. Treatment in the individual patient should be based on health status and patient preference.

Metastatic castration-resistant prostate cancer in very elderly patients: challenges and solutions

The treatment of elderly patients with cancer is usually viewed by clinicians as a challenge, because of the age-related decline in normal organ function and the frequent concomitant administration of multiple drugs for comorbid conditions. Clinicians therefore tend not to prescribe antineoplastic agents (mainly in the case of chemotherapy) to elderly patients, with the fear of excess toxicity leading to an unfavorable cost:benefit ratio. The cutoff age defining a cancer patient as elderly is usually 70 years, but over the last 10 years clinicians have paid more attention to functional status, as evaluated by means of a comprehensive geriatric assessment and comorbidity burden, rather than chronological age. In the case of metastatic castration-resistant prostate cancer (mCRPC), depending on their age at the time of diagnosis of PC, many (if not most) of the patients are more than 70 years old, and a fair number are very elderly patients aged ≥80 years. The availability of various agents capable of significantly prolonging survival has dramatically changed the therapeutic landscape of mCRPC patients, but very elderly patients are usually underrepresented in pivotal trials. This narrative review considers the available data concerning elderly and very elderly mCRPC patients enrolled in pivotal trials and the information provided by reports of everyday clinical practice, in order to explore the challenges related to the clinical management of this special population.