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.

Improved Outcomes with Enzalutamide in Biochemically Recurrent Prostate Cancer.

BACKGROUND: Patients with prostate cancer who have high-risk biochemical recurrence have an increased risk of progression. The efficacy and safety of enzalutamide plus androgen-deprivation therapy and enzalutamide monotherapy, as compared with androgen-deprivation therapy alone, are unknown. METHODS: In this phase 3 trial, we enrolled patients with prostate cancer who had high-risk biochemical recurrence with a prostate-specific antigen doubling time of 9 months or less. Patients were randomly assigned, in a 1:1:1 ratio, to receive enzalutamide (160 mg) daily plus leuprolide every 12 weeks (combination group), placebo plus leuprolide (leuprolide-alone group), or enzalutamide monotherapy (monotherapy group). The primary end point was metastasis-free survival, as assessed by blinded independent central review, in the combination group as compared with the leuprolide-alone group. A key secondary end point was metastasis-free survival in the monotherapy group as compared with the leuprolide-alone group. Other secondary end points were patient-reported outcomes and safety. RESULTS: A total of 1068 patients underwent randomization: 355 were assigned to the combination group, 358 to the leuprolide-alone group, and 355 to the monotherapy group. The patients were followed for a median of 60.7 months. At 5 years, metastasis-free survival was 87.3% (95% confidence interval [CI], 83.0 to 90.6) in the combination group, 71.4% (95% CI, 65.7 to 76.3) in the leuprolide-alone group, and 80.0% (95% CI, 75.0 to 84.1) in the monotherapy group. With respect to metastasis-free survival, enzalutamide plus leuprolide was superior to leuprolide alone (hazard ratio for metastasis or death, 0.42; 95% CI, 0.30 to 0.61; P<0.001); enzalutamide monotherapy was also superior to leuprolide alone (hazard ratio for metastasis or death, 0.63; 95% CI, 0.46 to 0.87; P = 0.005). No new safety signals were observed, with no substantial between-group differences in quality-of-life measures. CONCLUSIONS: In patients with prostate cancer with high-risk biochemical recurrence, enzalutamide plus leuprolide was superior to leuprolide alone with respect to metastasis-free survival; enzalutamide monotherapy was also superior to leuprolide alone. The safety profile of enzalutamide was consistent with that shown in previous clinical studies, with no apparent detrimental effect on quality of life. (Funded by Pfizer and Astellas Pharma; EMBARK ClinicalTrials.gov number, NCT02319837.).

The Efficacy of Enzalutamide plus Androgen Deprivation Therapy in Oligometastatic Hormone-sensitive Prostate Cancer: A Post Hoc Analysis of ARCHES.

BACKGROUND: Few phase 3 studies have evaluated optimal systemic treatment strategies for patients with oligometastatic hormone-sensitive prostate cancer (HSPC), who may be at risk of undertreatment. OBJECTIVE: To evaluate outcomes for patients with oligometastatic and polymetastatic HSPC treated with enzalutamide plus androgen deprivation therapy (ADT) versus placebo plus ADT. DESIGN, SETTING, AND PARTICIPANTS: This was a post hoc analysis of data for 927 patients with nonvisceral metastatic HSPC in the ARCHES trial (NCT02677896). INTERVENTION: Patients were randomized 1:1 to enzalutamide (160 mg/d orally) plus ADT or placebo plus ADT with HSPC categorized as oligometastatic (1-5 metastases) or polymetastatic (≥6 metastases). OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS: The treatment effect on radiographic progression-free survival (rPFS), overall survival (OS), and secondary efficacy endpoints was evaluated in terms of the number of metastases. Safety was assessed. Cox proportional hazards models were used to generate hazard ratios (HRs). The Brookmeyer and Crowley method was used to generate 95% confidence intervals (CIs) for Kaplan-Meier median values. RESULTS AND LIMITATIONS: Enzalutamide plus ADT improved rPFS (HR 0.27, 95% CI 0.16-0.46; p < 0.001), OS (HR 0.59, 95% CI 0.40-0.87; p < 0.005), and secondary endpoints in patients with oligometastatic or polymetastatic disease (rPFS: HR 0.33, 95% CI 0.23-0.46; p < 0.001; OS: HR 0.55, 95% CI 0.41-0.74; p < 0.001). Safety profiles were generally similar across subgroups. Limitations include the small numbers of patients with fewer than three metastases. CONCLUSIONS: This post hoc analysis demonstrated the utility of enzalutamide, irrespective of metastatic burden or type of oligometastatic disease, and suggests that earlier treatment intensification with systemic potent androgen receptor inhibition is advantageous. PATIENT SUMMARY: This study considered two treatment options for metastatic hormone-sensitive prostate cancer in patients with one to five metastases or six or more metastases. Treatment with enzalutamide plus ADT improved survival and other outcomes over ADT alone, whether patients had few or many metastases.

The impact of enzalutamide on quality of life in men with metastatic hormone-sensitive prostate cancer based on prior therapy, risk, and symptom subgroups.

BACKGROUND: Enzalutamide plus androgen deprivation therapy (ADT) improved radiographic progression-free survival versus ADT alone in patients with metastatic hormone-sensitive prostate cancer (mHSPC) in ARCHES (NCT02677896). While health-related quality of life (HRQoL) was generally maintained in the intent-to-treat population, we further analyzed patient-reported outcomes (PROs) in defined subgroups. METHODS: ARCHES was a randomized, double-blind, placebo-controlled, phase 3 study. Patients with mHSPC received enzalutamide (160 mg/day) plus ADT (n = 574) or placebo plus ADT (n = 576). Questionnaires, including the Functional Assessment of Cancer Therapy-Prostate, Brief Pain Inventory-Short Form, and EuroQol 5-Dimension, 5-Level (EQ-5D-5L), were completed at baseline, Week 13, and every 12 weeks until disease progression. PRO endpoints were time to first confirmed clinically meaningful deterioration (TTFCD) in HRQoL or pain. Subgroups included prognostic risk, pain/HRQoL, prior docetaxel, and local therapy (radical prostatectomy [RP] and/or radiotherapy [RT]). RESULTS: There were several between-treatment differences in TTFCD for pain and functioning/HRQoL PROs. Enzalutamide plus ADT delayed TTFCD for worst pain in the prior RT group (not reached vs. 14.06 months; hazard ratio [HR]: 0.56 [95% confidence interval: 0.34-0.94]) and pain interference in low-baseline-HRQoL group (19.32 vs. 11.20 months; HR: 0.64 [0.44-0.94]) versus placebo plus ADT. In prior/no prior RP, prior RT, prior local therapy, no prior docetaxel, mild baseline pain, and low-risk subgroups, TTFCD was delayed for the EQ-5D-5L visual analog scale. CONCLUSION: Enzalutamide plus ADT provides clinical benefits in defined patient subgroups versus ADT alone, while maintaining lack of pain and high HRQoL, with delayed deterioration in several HRQoL measures.

Improved Survival With Enzalutamide in Patients With Metastatic Hormone-Sensitive Prostate Cancer.

Clinical trials frequently include multiple end points that mature at different times. The initial report, typically based on the primary end point, may be published when key planned co-primary or secondary analyses are not yet available. Clinical Trial Updates provide an opportunity to disseminate additional results from studies, published in JCO or elsewhere, for which the primary end point has already been reported.In primary analysis, enzalutamide plus androgen deprivation therapy (ADT) improved radiographic progression-free survival (rPFS) in patients with metastatic hormone-sensitive prostate cancer (mHSPC); however, overall survival data were immature. In the phase III, double-blind, global ARCHES trial (ClinicalTrials.gov identifier: NCT02677896), 1,150 patients with mHSPC were randomly assigned 1:1 to enzalutamide (160 mg once daily) plus ADT or placebo plus ADT, stratified by disease volume and prior docetaxel use. Here, we report the final prespecified analysis of overall survival (key secondary end point) and an update on rPFS, other secondary end points, and safety. After unblinding, 180 (31.3%) progression-free patients randomly assigned to placebo plus ADT crossed over to open-label enzalutamide plus ADT. As of May 28, 2021 (median follow-up, 44.6 months), 154 of 574 patients randomly assigned to enzalutamide plus ADT and 202 of 576 patients randomly assigned to placebo plus ADT had died. Enzalutamide plus ADT reduced risk of death by 34% versus placebo plus ADT (median not reached in either group; hazard ratio, 0.66; 95% CI, 0.53 to 0.81; P < .001). Enzalutamide plus ADT continued to improve rPFS and other secondary end points. Adverse events were generally consistent with previous reports of long-term enzalutamide use. In conclusion, enzalutamide plus ADT significantly prolongs survival versus placebo plus ADT in patients with mHSPC.

Effect of enzalutamide on PK of P-gp and BCRP substrates in cancer patients: CYP450 induction may not always predict overall effect on transporters.

Drug-drug interaction (DDI) is an important consideration for clinical decision making in prostate cancer treatment. The objective of this study was to evaluate the effect of enzalutamide, an oral androgen receptor inhibitor, on the pharmacokinetics (PK) of digoxin (P-glycoprotein [P-gp] probe substrate) and rosuvastatin (breast cancer resistance protein [BCRP] probe substrate) in men with metastatic castration-resistant prostate cancer (mCRPC). This was a phase I, open-label, fixed-sequence, crossover study (NCT04094519). Eligible men with mCRPC received a single dose of transporter probe cocktail containing 0.25 mg digoxin and 10 mg rosuvastatin plus enzalutamide placebo-to-match on day 1. On day 8, patients started 160 mg enzalutamide once daily through day 71. On day 64, patients also received a single dose of the cocktail. The primary end points were digoxin and rosuvastatin plasma maximum concentration (Cmax ), area under the concentration-time curve from the time of dosing to the last measurable concentration (AUClast ), and AUC from the time of dosing extrapolated to time infinity (AUCinf ). Secondary end points were enzalutamide and N-desmethyl enzalutamide (metabolite) plasma Cmax , AUC during a dosing interval, where tau is the length of the dosing interval (AUCtau ), and concentration immediately prior to dosing at multiple dosing (Ctrough ). When administered with enzalutamide, there was a 17% increase in Cmax , 29% increase in AUClast , and 33% increase in AUCinf of plasma digoxin compared to digoxin alone, indicating that enzalutamide is a "mild" inhibitor of P-gp. No PK interaction was observed between enzalutamide and rosuvastatin (BCRP probe substrate). The PK of enzalutamide and N-desmethyl enzalutamide were in agreement with previously reported data. The potential for transporter-mediated DDI between enzalutamide and digoxin and rosuvastatin is low in men with prostate cancer. Therefore, concomitant administration of enzalutamide with medications that are substrates for P-gp and BCRP does not require dose adjustment in this patient population.

Enzalutamide versus bicalutamide in patients with nonmetastatic castration-resistant prostate cancer: a prespecified subgroup analysis of the STRIVE trial.

BACKGROUND: In the phase 2, randomized, double-blind STRIVE trial, enzalutamide significantly reduced the risk of prostate cancer progression or death versus bicalutamide in patients with metastatic castration-resistant prostate cancer (mCRPC) and nonmetastatic CRPC (nmCRPC). The objective of this protocol-specified subgroup analysis of STRIVE was to investigate the benefit of enzalutamide versus bicalutamide specifically in patients with nmCRPC. METHODS: Patients (N = 139) were stratified by disease stage and randomized to enzalutamide 160 mg/day plus androgen deprivation therapy (ADT; n = 70) or bicalutamide 50 mg/day plus ADT (n = 69). RESULTS: Baseline characteristics of patients with nmCRPC were comparable between groups. At a median of 17 months follow-up, enzalutamide reduced the risk of progression or death by 76% versus bicalutamide in patients with nmCRPC (hazard ratio [HR], 0.24; 95% CI 0.14-0.42). Enzalutamide reduced risk of prostate-specific antigen progression by 82% versus bicalutamide in patients with nmCRPC (HR, 0.18; 95% CI 0.10-0.34). The most frequently reported adverse events by patients receiving enzalutamide were fatigue (36.2%), hot flush (20.3%), decreased appetite (17.4%), dizziness (17.4%), and nausea (17.4%). CONCLUSIONS: This STRIVE subgroup analysis of patients with nmCRPC illustrates the benefit of enzalutamide in reducing the risk of progression or death versus bicalutamide in patients with nmCRPC. TRIAL REGISTRATION: ClinicalTrials.gov identifier NCT01664923.

Efficacy of enzalutamide in subgroups of men with metastatic hormone-sensitive prostate cancer based on prior therapy, disease volume, and risk.

BACKGROUND: While enzalutamide plus androgen deprivation therapy (ADT) significantly reduces the risk of radiographic progression-free survival (rPFS) and improves overall survival in metastatic hormone-sensitive prostate cancer (mHSPC), the efficacy in clinically relevant subgroups of patients based on prior local and systemic therapy, disease volume, and risk has not been analyzed to date. These post hoc analyses of the phase 3 ARCHES trial (NCT02677896) evaluated the efficacy of enzalutamide plus ADT according to prior local and systemic treatment, disease volume, and risk, assessed at trial baseline. METHODS: In ARCHES, a global, double-blind, placebo-controlled, phase 3 study, 1150 patients with mHSPC were randomized 1:1 to receive enzalutamide (160 mg/day) plus ADT or placebo plus ADT, stratified by prior docetaxel therapy and disease volume. Primary endpoint was rPFS. Secondary endpoints included time to prostate-specific antigen progression, symptomatic skeletal events, and prostate-specific antigen and radiographic responses. Analyses of clinical endpoints were completed by prior local therapy, prior docetaxel exposure, CHAARTED (NCT00309985)-defined disease volume, and LATITUDE (NCT01715285)-defined risk groups. RESULTS: Patients were randomized to enzalutamide plus ADT (n = 574) and placebo plus ADT (n = 576). Enzalutamide plus ADT significantly improved rPFS (hazard ratio: 0.39; p < 0.0001), with similar improvements reported in all subgroups based on prior local and docetaxel treatment, disease volume, and risk. Treatment benefits were observed with enzalutamide plus ADT in multiple secondary clinical endpoints in the overall population and all subgroups. CONCLUSIONS: Enzalutamide plus ADT demonstrated clinical benefit across all patients with mHSPC, irrespective of prior local and systemic treatment, disease volume, and risk.

A phase 3 randomised study of enzalutamide plus leuprolide and enzalutamide monotherapy in high-risk non-metastatic hormone-sensitive prostate cancer with rising PSA after local therapy: EMBARK study design.

INTRODUCTION: Limited data from controlled clinical trials are available for men who experience biochemical recurrence after definitive therapy for prostate cancer. In the absence of overt metastases, patients with non-metastatic castration-sensitive prostate cancer (nmCSPC) often receive androgen deprivation therapy (ADT). There is no standard-of-care consensus on optimal ADT timing, although most men are treated prior to metastases, especially those with high-risk features (Gleason score 8-10 or prostate-specific antigen doubling time (PSADT) <9-12 months). Given data that ADT plus novel hormonal agents improve survival in men with metastatic CSPC, there is a desire to evaluate these agents earlier in the disease course. The main objective of EMBARK is the comparative assessment of enzalutamide plus leuprolide (luteinising hormone-releasing hormone agonist (LHRHa)) or enzalutamide monotherapy versus monotherapy LHRHa to improve metastasis-free survival (MFS) in patients with high-risk nmCSPC PSA recurrence after definitive therapy. METHODS AND ANALYSIS: EMBARK is a randomised, phase 3 study of high-risk patients with nmCSPC, a PSADT of ≤9 months and a screening PSA of ≥2 ng/mL above the nadir after radiotherapy (RT) or ≥1 ng/mL after radical prostatectomy (RP) with or without postoperative RT. Men (n=1050) are randomised 1:1:1 to enzalutamide 160 mg/day plus LHRHa or placebo plus LHRHa (double-blind arms) or enzalutamide monotherapy (open-label arm). Treatment is suspended at week 37 if PSA concentrations are <0.2 ng/mL and reinstated if levels rise to ≥2.0 ng/mL with RP or ≥5.0 ng/mL without RP. Patients with PSA ≥0.2 ng/mL at week 37 continue until treatment discontinuation criteria are met. The primary endpoint is MFS comparing enzalutamide plus LHRHa versus placebo plus LHRHa. ETHICS AND DISSEMINATION: The study is conducted under the guiding principles of the World Medical Association Declaration of Helsinki. The results will be disseminated at research conferences and in peer-reviewed journals. TRIAL REGISTRATION NUMBER: NCT02319837.

Efficacy of Enzalutamide plus Androgen Deprivation Therapy in Metastatic Hormone-Sensitive Prostate Cancer by Pattern of Metastatic Spread: ARCHES Post Hoc Analyses.

PURPOSE: Enzalutamide plus androgen deprivation therapy has previously been shown to improve clinical outcomes in men with metastatic hormone-sensitive prostate cancer (ARCHES; NCT02677896). Here, we assessed if and how the pattern of metastatic spread impacts efficacy of enzalutamide plus androgen deprivation therapy in men enrolled in ARCHES. MATERIALS AND METHODS: Men with metastatic hormone-sensitive prostate cancer were randomized 1:1 to enzalutamide (160 mg/day) plus androgen deprivation therapy or placebo plus androgen deprivation therapy, stratified by disease volume and prior docetaxel treatment. The primary end point was radiographic progression-free survival. Secondary end points included time to prostate specific antigen progression, initiation of new antineoplastic therapy, first symptomatic skeletal event and castration resistance. Post hoc analyses were performed by pattern of metastatic spread based on study entry imaging. RESULTS: Of the overall population with metastases identified at enrollment (1,146), the largest patient subgroups were those with bone metastases only (513) and those with bone plus lymph node metastases (351); there were fewer men with lymph node metastases only (154) and men with visceral±bone or lymph node metastases (128). Enzalutamide plus androgen deprivation therapy reduced the risk of radiographic progression vs placebo plus androgen deprivation therapy in men with bone metastases only (HR 0.33) and bone plus lymph node metastases (HR 0.31). Similar improvements in secondary end points were also observed in these subgroups. CONCLUSIONS: These findings indicate that treatment with enzalutamide plus androgen deprivation therapy provides improvements in men with bone and/or lymph node metastases but may be less effective in men with visceral patterns of spread.

Neoadjuvant Enzalutamide Prior to Prostatectomy.

Purpose: Prostate cancer is dependent on androgen receptor (AR) activation. Optimal AR antagonism may effectively cytoreduce local disease and suppress or eliminate micrometastases. We evaluated neoadjuvant therapy prior to prostatectomy with the potent AR antagonist enzalutamide (enza) either alone or in combination with dutasteride (dut) and leuprolide (enza/dut/luteinizing hormone-releasing hormone analogues [LHRHa]).Experimental Design: Forty-eight of 52 men with intermediate or high-risk localized prostate cancer proceeded to prostatectomy after neoadjuvant enzalutamide or enza/dut/LHRHa for 6 months. We assessed pathologic complete response (pCR), minimal residual disease (MRD; ≤3 mm maximum diameter of residual disease), residual cancer burden (RCB), and expression of PSA and serum and tissue androgen concentrations. We compared the proportion of patients with pCR in each treatment arm with a historical control rate of 5%, based on previous reports of flutamide with LHRHa.Results: In the enzalutamide arm, none of the 25 patients achieved pCR or MRD. In the enza/dut/LHRHa arm, one of 23 patients (4.3%) achieved pCR and 3 of 23 (13.0%) achieved MRD. Median RCB was higher in the enzalutamide arm than in the enza/dut/LHRHa arm (0.41 cm3 vs. 0.06 cm3, respectively). Tissue testosterone and dihydrotestosterone levels correlated with RCB. No adverse events leading to study drug discontinuation were reported.Conclusions: Combination therapy with enza/dut/LHRHa resulted in pCR and MRD rates comparable with historical controls. Evidence of continued AR activity in residual tumor suggests that AR signaling may contribute to survival. Strategies to more effectively ablate AR activity are warranted to determine whether more substantial antitumor effects are observed. Clin Cancer Res; 23(9); 2169-76. ©2016 AACR.

Association of MnSOD AA Genotype with the Progression of Prostate Cancer.

PURPOSE: To investigate whether manganese superoxide dismutase (MnSOD) genetic polymorphism is associated with the clinical significance of prostate cancer. MATERIALS AND METHODS: Prostates were obtained from 194 deceased men 45 years or older who did not have a history of prostate cancer. Serial sections and histological examinations of the prostate were performed. The MnSOD genotypes of the specimens were determined by polymerase chain reaction restriction fragment length polymorphism analysis. RESULTS: Of the 194 men, 31 and 26 had clinically insignificant and significant prostate cancer. Clinically significant cancer comprised 29% and 58% of the cancers in men <70 and >70 years old, respectively. The age-specific proportion of significant cancer significantly increased with the advance of age (p<0.001). MnSOD AA, as compared with the other genotypes (VA and VV together), was associated with significant prostate cancer across all ages, odds ratio (OR) 2.34, 95% confidence interval (CI) 0.99-5.49, and in men older than 69 years (OR 4.89, 95% CI 1.51-15.8), but not in men younger than 70 years. The genotype was not associated with clinically insignificant cancer regardless of age. The comparison between significant and insignificant cancer, the OR (95% CI) for MnSOD AA was 5.04 (1.05-24.2) (sensitivity 0.57, specificity 0.78, positive predictive value 0.78) in men older than 69 years. CONCLUSIONS: MnSOD polymorphism is strongly associated with the clinical significance of prostate cancer in men older than 69 years, but not in men younger than 70 years suggesting that oxidative stress may be involved in the progression of the disease. MnSOD may be a clinically useful marker to predict the potential of progression of prostate cancer.

An update on enzalutamide in the treatment of prostate cancer.

Enzalutamide is an oral androgen receptor inhibitor that targets multiple steps in the androgen receptor signaling pathway. In the randomized phase III AFFIRM study, significant improvements in survival versus placebo were observed when enzalutamide was used as a treatment for patients with metastatic castration-resistant prostate cancer (mCRPC) following prior treatment with docetaxel. Additional benefits included significant delay in time to first skeletal-related event, and improvement in several measures of pain and health-related quality of life. Treatment effects were consistent across all prespecified subgroups. The phase III PREVAIL study evaluated enzalutamide versus placebo in patients with mCRPC who had not received chemotherapy. Enzalutamide significantly decreased the risk of radiographic progression and death. There were also significant improvements in all secondary and prespecified exploratory endpoints, including delayed initiation of chemotherapy, reduction in risk of first skeletal-related event and a high percentage of patients with objective response compared with placebo. Enzalutamide was also studied in hormone naïve patients (as monotherapy) in a small, open-label phase II study in patients with prostate cancer who were eligible for androgen-deprivation therapy. A prostate-specific antigen (PSA) response, defined as ⩾80% decline in PSA level from baseline at week 25, was achieved in 92.5% of patients. Long-term follow up is ongoing. Despite differences between these three trials, enzalutamide displayed a favorable safety profile in all three patient populations. Similar rates of adverse events between the enzalutamide and placebo groups were observed in AFFIRM and PREVAIL, with fatigue, diarrhea, back pain and hot flashes being more common with enzalutamide than with placebo. Hypertension was reported at a higher rate in the enzalutamide group than in the placebo group in PREVAIL. Breast-related disorders associated with enzalutamide treatment were also reported in the Monotherapy trial. Few seizures were reported in any trial. Enzalutamide is being studied in several early disease state populations.

A randomized, double-blind, solifenacin succinate versus placebo control, phase 4, multicenter study evaluating urinary continence after robotic assisted radical prostatectomy.

PURPOSE: Bladder dysfunction influences recovery of urinary continence after radical prostatectomy. We performed a multicenter, randomized, double-blind study evaluating solifenacin vs placebo on return to continence in patients who were still incontinent 7 to 21 days after catheter removal after robot-assisted radical prostatectomy. MATERIALS AND METHODS: A wireless personal digital assistant was given to patients the day of catheter removal. Encrypted answers were transmitted daily to dedicated servers. After a 7 to 21-day treatment-free washout period, patients requiring 2 to 10 pads per day for 7 consecutive days were randomized (1:1) to 5 mg solifenacin daily or placebo. The primary end point was time from first dose to continence defined as 0 pads per day or a dry security pad for 3 consecutive days. Secondary end points included proportion of patients continent at end of study, average change in pads per day number and quality of life assessments. RESULTS: A total of 1,086 screened patients recorded personal digital assistant information. Overall 640 patients were randomized to solifenacin vs placebo and 17 failed to take medication. There was no difference in time to continence (p=0.17). Continence was achieved by study end in 91 of 313 (29%) vs 66 of 309 (21%), respectively (p=0.04). Pads per day change from baseline was -3.2 and -2.9, respectively (p=0.03). Dry mouth was the only common adverse event seen in 6.1% and 0.6%, respectively. Constipation rates were similar. The overall rate of continence in the entire population from screening to end of study was 73%. CONCLUSIONS: There was no effect on primary outcome but some secondary end points benefited the solifenacin arm. The study provides level 1B clinical evidence for continence outcomes after robot-assisted radical prostatectomy.

Efficacy outcomes by baseline prostate-specific antigen quartile in the AFFIRM trial.

BACKGROUND: Enzalutamide significantly prolonged the survival of men with metastatic castration-resistant prostate cancer (PCa) after docetaxel in the randomised, phase 3, double-blind, placebo-controlled, multinational Patients with Progressive Castration-Resistant Prostate Cancer Previously Treated with Docetaxel-Based Chemotherapy (AFFIRM) trial (NCT00974311). Prostate-specific antigen (PSA) is commonly used as a marker of PCa disease burden, and the relationship of baseline PSA level to consequent treatment effect is of clinical interest. OBJECTIVE: Exploratory analysis to evaluate any differences in patient characteristics and efficacy outcomes by baseline PSA level in the AFFIRM trial. DESIGN, SETTING, AND PARTICIPANTS: Post hoc subanalysis of all randomised patients (n=1199) from the AFFIRM trial. INTERVENTION: Participants were randomly assigned in a two-to-one ratio to receive oral enzalutamide 160 mg/d or placebo. OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS: The major clinical efficacy end points were overall survival (OS), radiographic progression-free survival (rPFS), and time to PSA progression (TTPP) versus placebo; baseline characteristics, treatment duration, and subsequent antineoplastic therapy were compared by baseline PSA quartile. RESULTS AND LIMITATIONS: Baseline PSA quartiles corresponded to the following PSA groups: <40 ng/ml (n=299), 40 to <111 ng/ml (n=300), 111 to <406 ng/ml (n=300), and ≥406 ng/ml (n=300). Enzalutamide consistently improved OS, rPFS, and TTPP compared with placebo across all subgroups, regardless of baseline PSA level. Hazard ratios for improvements in OS were 0.55 (95% confidence interval [CI], 0.36-0.85), 0.69 (95% CI, 0.47-1.02), 0.73 (95% CI, 0.53-1.01), and 0.53 (95% CI, 0.39-0.73) for PSA groups 1-4, respectively. The post hoc design of this analysis was not statistically powered to assess the relationship between baseline PSA and clinical efficacy outcomes. CONCLUSIONS: This post hoc analysis of the AFFIRM trial demonstrates consistent benefits in OS, rPFS, and TTPP with enzalutamide regardless of baseline disease severity, as assessed by PSA. PATIENT SUMMARY: Exploratory post hoc analysis of the AFFIRM trial showed that enzalutamide improves overall survival, radiographic progression-free survival, and time to prostate-specific antigen progression compared with placebo regardless of baseline disease severity, as assessed by prostate-specific antigen. TRIAL REGISTRATION: ClinicalTrials.gov identifier NCT00974311.

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

OBJECTIVE: To explore any differences in efficacy and safety outcomes between European (EU) (n = 684) and North American (NA) (n = 395) patients in the AFFIRM trial (NCT00974311). PATIENTS AND METHODS: Phase III, double-blind, placebo-controlled, multinational AFFIRM trial in men with metastatic castration-resistant prostate cancer (mCRPC) after docetaxel. Participants were randomly assigned in a 2:1 ratio to receive oral enzalutamide 160 mg/day or placebo. The primary end point was overall survival (OS) in a post hoc analysis. RESULTS: Enzalutamide significantly improved OS compared with placebo in both EU and NA patients. The median OS in EU patients was longer than NA patients in both treatment groups. However, the relative treatment effect, expressed as hazard ratio and 95% confidence interval, was similar in both regions: 0.64 (0.50, 0.82) for EU and 0.63 (0.47, 0.83) for NA. Significant improvements in other end points further confirmed the benefit of enzalutamide over placebo in patients from both regions. The tolerability profile of enzalutamide was comparable between EU and NA patients, with fatigue and nausea the most common adverse events. Four EU patients (4/461 enzalutamide-treated, 0.87%) and one NA patient (1/263 enzalutamide-treated, 0.38%) had seizures. The difference in median OS was related in part to the timing of development of mCRPC and baseline demographics on study entry. CONCLUSION: This post hoc exploratory analysis of the AFFIRM trial showed a consistent OS benefit for enzalutamide in men with mCRPC who had previously progressed on docetaxel in both NA- and EU-treated patients, although the median OS was higher in EU relative to NA patients. Efficacy benefits were consistent across end points, with a comparable safety profile in both regions.