Androgen Receptor Targeted Treatments of Prostate Cancer: 35 Years of Progress with Antiandrogens.

PURPOSE: Antiandrogens inhibit the androgen receptor and have an important role in the treatment of prostate cancer. This review provides a historical perspective on the development and clinical benefit of antiandrogens in the treatment of prostate cancer. MATERIALS AND METHODS: We searched PubMed® for clinical trials with the search terms antiandrogens and prostate cancer combined with drug names for antiandrogens. This article represents a collaboration of clinical investigators who have made critical scientific contributions leading to the approval of antiandrogens for treating patients with prostate cancer. RESULTS: Antiandrogens differ in chemical structure and exert varying efficacy and safety profiles. The unfavorable therapeutic index of steroidal antiandrogens led to replacement by safer nonsteroidal agents. Flutamide, nilutamide and bicalutamide, which were designed to target the androgen receptor, were developed primarily for use in combination with castration to provide combined androgen blockade. Modest clinical benefits were observed with the combination of first generation antiandrogens and castration vs castration alone. With increased knowledge of androgen receptor structure and its biological functions a new generation of antiandrogens without agonist activity was designed to provide more potent inhibition of the androgen receptor. Randomized clinical trials in patients with metastatic, castration resistant prostate cancer showed significant survival benefits, which led to the approval of enzalutamide in August 2012. Apalutamide was recently approved while darolutamide is not yet approved in the United States. These next generation antiandrogens are being actively tested in earlier disease states such as nonmetastatic prostate cancer. Evolving knowledge of resistance mechanisms to androgen receptor targeted treatments will stimulate research and drug discovery for additional compounds. Further testing in nonmetastatic castration resistant prostate cancer as well as castration sensitive disease states will hopefully augment our ability to treat a broader spectrum of patients with prostate cancer. CONCLUSIONS: Antiandrogens have already provided important benefits for prostate cancer treatment. Greater knowledge about the structural and functional biology of the androgen receptor in prostate cancer will facilitate further discovery and development of further improved antiandrogens with enhanced clinical activity in patients with advanced metastatic disease. Testing these new agents earlier in the course of prostate cancer may further improve the survival and quality of life of patients with current local and/or systemic treatment modalities.

Intermittent versus continuous androgen deprivation in prostate cancer.

BACKGROUND: Castration resistance occurs in most patients with metastatic hormone-sensitive prostate cancer who are receiving androgen-deprivation therapy. Replacing androgens before progression of the disease is hypothesized to prolong androgen dependence. METHODS: Men with newly diagnosed, metastatic, hormone-sensitive prostate cancer, a performance status of 0 to 2, and a prostate-specific antigen (PSA) level of 5 ng per milliliter or higher received a luteinizing hormone-releasing hormone analogue and an antiandrogen agent for 7 months. We then randomly assigned patients in whom the PSA level fell to 4 ng per milliliter or lower to continuous or intermittent androgen deprivation, with patients stratified according to prior or no prior hormonal therapy, performance status, and extent of disease (minimal or extensive). The coprimary objectives were to assess whether intermittent therapy was noninferior to continuous therapy with respect to survival, with a one-sided test with an upper boundary of the hazard ratio of 1.20, and whether quality of life differed between the groups 3 months after randomization. RESULTS: A total of 3040 patients were enrolled, of whom 1535 were included in the analysis: 765 randomly assigned to continuous androgen deprivation and 770 assigned to intermittent androgen deprivation. The median follow-up period was 9.8 years. Median survival was 5.8 years in the continuous-therapy group and 5.1 years in the intermittent-therapy group (hazard ratio for death with intermittent therapy, 1.10; 90% confidence interval, 0.99 to 1.23). Intermittent therapy was associated with better erectile function and mental health (P<0.001 and P=0.003, respectively) at month 3 but not thereafter. There were no significant differences between the groups in the number of treatment-related high-grade adverse events. CONCLUSIONS: Our findings were statistically inconclusive. In patients with metastatic hormone-sensitive prostate cancer, the confidence interval for survival exceeded the upper boundary for noninferiority, suggesting that we cannot rule out a 20% greater risk of death with intermittent therapy than with continuous therapy, but too few events occurred to rule out significant inferiority of intermittent therapy. Intermittent therapy resulted in small improvements in quality of life. (Funded by the National Cancer Institute and others; ClinicalTrials.gov number, NCT00002651.).

Intermittent androgen suppression for rising PSA level after radiotherapy.

BACKGROUND: Intermittent androgen deprivation for prostate-specific antigen (PSA) elevation after radiotherapy may improve quality of life and delay hormone resistance. We assessed overall survival with intermittent versus continuous androgen deprivation in a noninferiority randomized trial. METHODS: We enrolled patients with a PSA level greater than 3 ng per milliliter more than 1 year after primary or salvage radiotherapy for localized prostate cancer. Intermittent treatment was provided in 8-month cycles, with nontreatment periods determined according to the PSA level. The primary end point was overall survival. Secondary end points included quality of life, time to castration-resistant disease, and duration of nontreatment intervals. RESULTS: Of 1386 enrolled patients, 690 were randomly assigned to intermittent therapy and 696 to continuous therapy. Median follow-up was 6.9 years. There were no significant between-group differences in adverse events. In the intermittent-therapy group, full testosterone recovery occurred in 35% of patients, and testosterone recovery to the trial-entry threshold occurred in 79%. Intermittent therapy provided potential benefits with respect to physical function, fatigue, urinary problems, hot flashes, libido, and erectile function. There were 268 deaths in the intermittent-therapy group and 256 in the continuous-therapy group. Median overall survival was 8.8 years in the intermittent-therapy group versus 9.1 years in the continuous-therapy group (hazard ratio for death, 1.02; 95% confidence interval, 0.86 to 1.21). The estimated 7-year cumulative rates of disease-related death were 18% and 15% in the two groups, respectively (P=0.24). CONCLUSIONS: Intermittent androgen deprivation was noninferior to continuous therapy with respect to overall survival. Some quality-of-life factors improved with intermittent therapy. (Funded by the Canadian Cancer Society Research Institute and others; ClinicalTrials.gov number, NCT00003653.).

The clinical and economic implications of specimen provenance complications in diagnostic prostate biopsies.

PURPOSE: Inaccurate diagnoses of prostate cancer can result from transposition or contamination of patient biopsy specimens, which are known as specimen provenance complications. We assessed the clinical and economic burden of specimen provenance complications in prostate biopsies in the United States. MATERIALS AND METHODS: We performed a comprehensive, systematic review of the literature to approximate the effect of specimen provenance complications on direct medical costs, patient QALYs and medicolegal costs. Data were extracted from published studies on specimen provenance complications rates, prostate cancer treatment efficacy, treatment cost, litigation/settlement costs after false diagnoses of prostate biopsies and patient quality of life. Sensitivity analysis was done to identify factors that most influenced the outcomes and assess the robustness of the findings. RESULTS: Of the estimated 806,251 primary and secondary prostate biopsies performed annually in the United States 20,322 specimen provenance complications were projected to result in 4,570 clinically meaningful false diagnoses and an expected loss of 634 QALYs. The total burden of specimen provenance complications was projected to exceed $879.9 million or $3,776 per positive cancer diagnosis. This estimate was most sensitive to the indemnity cost per false-positive case and the rate of transpositions at independent reference laboratories. CONCLUSIONS: The societal burden of specimen provenance complications in patients who undergo prostate biopsy exceeds $880 million annually in the United States. This analysis framework may be useful as policy makers, health organizations and researchers seek to decrease false diagnoses of prostate cancer and the consequent effects of delayed or unnecessary treatment. Further study is warranted to quantify the economic burden among additional diseases.

Sipuleucel-T immunotherapy for castration-resistant prostate cancer.

BACKGROUND: Sipuleucel-T, an autologous active cellular immunotherapy, has shown evidence of efficacy in reducing the risk of death among men with metastatic castration-resistant prostate cancer. METHODS: In this double-blind, placebo-controlled, multicenter phase 3 trial, we randomly assigned 512 patients in a 2:1 ratio to receive either sipuleucel-T (341 patients) or placebo (171 patients) administered intravenously every 2 weeks, for a total of three infusions. The primary end point was overall survival, analyzed by means of a stratified Cox regression model adjusted for baseline levels of serum prostate-specific antigen (PSA) and lactate dehydrogenase. RESULTS: In the sipuleucel-T group, there was a relative reduction of 22% in the risk of death as compared with the placebo group (hazard ratio, 0.78; 95% confidence interval [CI], 0.61 to 0.98; P=0.03). This reduction represented a 4.1-month improvement in median survival (25.8 months in the sipuleucel-T group vs. 21.7 months in the placebo group). The 36-month survival probability was 31.7% in the sipuleucel-T group versus 23.0% in the placebo group. The treatment effect was also observed with the use of an unadjusted Cox model and a log-rank test (hazard ratio, 0.77; 95% CI, 0.61 to 0.97; P=0.02) and after adjustment for use of docetaxel after the study therapy (hazard ratio, 0.78; 95% CI, 0.62 to 0.98; P=0.03). The time to objective disease progression was similar in the two study groups. Immune responses to the immunizing antigen were observed in patients who received sipuleucel-T. Adverse events that were more frequently reported in the sipuleucel-T group than in the placebo group included chills, fever, and headache. CONCLUSIONS: The use of sipuleucel-T prolonged overall survival among men with metastatic castration-resistant prostate cancer. No effect on the time to disease progression was observed. (Funded by Dendreon; ClinicalTrials.gov number, NCT00065442.)

Optimization of initial prostate biopsy in clinical practice: sampling, labeling and specimen processing.

PURPOSE: An optimal prostate biopsy in clinical practice is based on a balance among adequate detection of clinically significant prostate cancers (sensitivity), assuredness regarding the accuracy of negative sampling (negative predictive value), limited detection of clinically insignificant cancers and good concordance with whole gland surgical pathology results to allow accurate risk stratification and disease localization for treatment selection. Inherent within this optimization is variation of the core number, location, labeling and processing for pathological evaluation. To date, there is no consensus in this regard. The purpose of this review is to 1) define the optimal number and location of biopsy cores during primary prostate biopsy among men with suspected prostate cancer, 2) define the optimal method of labeling prostate biopsy cores for pathological processing which will provide relevant and necessary clinical information for all potential clinical scenarios, and 3) determine the maximal number of prostate biopsy cores allowable within a specimen jar which would not preclude accurate histological evaluation of the tissue. MATERIALS AND METHODS: A bibliographic search using PubMed® covering the period up to July 2012 yielded approximately 550 articles. Articles were reviewed and categorized based on which of the 3 objectives of this review was addressed. Data were extracted, analyzed and summarized. Recommendations are provided based on this literature review and our clinical experience. RESULTS: The use of 10 to 12-core extended sampling protocols increases cancer detection rates compared to traditional sextant sampling methods and reduces the likelihood of repeat biopsy by increasing negative predictive value, ultimately allowing more accurate risk stratification without increasing the likelihood of detecting insignificant cancers. As the number of cores increases above 12, the increase in diagnostic yield becomes marginal. Only limited evidence supports the use of initial biopsy schemes involving more than 12 cores or saturation. Apical and laterally directed sampling of the peripheral zone increases cancer detection rate, reduces the need for repeat biopsies and predicts pathological features on prostatectomy while transition zone biopsies do not. There are little data to suggest that knowing the exact site of an individual positive biopsy core provides meaningful clinical information. However, determining laterality of cancer on biopsy may be helpful for predicting sites of extracapsular extension and therapeutic planning. Placement of multiple biopsy cores in a single container (greater than 2) appears to compromise pathological evaluation, which can reduce cancer detection rate and increase the likelihood of equivocal diagnoses. CONCLUSIONS: A 12-core systematic biopsy that incorporates apical and far-lateral cores in the template distribution allows maximal cancer detection, avoids repeat biopsy, and provides information adequate for identifying men who need therapy and planning that therapy while minimizing the detection of occult, indolent prostate cancers. This literature review does not provide compelling evidence that individual site specific labeling of cores benefits clinical decision making regarding the management of prostate cancer. Based on the available literature, we recommend packaging no more than 2 cores in each jar to avoid reduction of the cancer detection rate through inadequate tissue sampling.

Role of estrogen in normal male function: clinical implications for patients with prostate cancer on androgen deprivation therapy.

PURPOSE: Patients with prostate cancer on androgen deprivation therapy with luteinizing hormone-releasing hormone agonists experience deleterious side effects, including sexual dysfunction, hot flashes and osteoporosis. Estrogen may relieve or reduce some of these side effects. We explore the role of estrogen in normal male function, emphasizing sexual interest and performance. MATERIALS AND METHODS: We reviewed the literature on androgen deprivation therapy, estrogen and sexual function in males using PubMed® and other sources. RESULTS: Estrogen receptors are present in tissues involved in sexual behavior including several brain centers and pelvic floor muscles. Exogenous estrogens can restore some sexual interest to greater than castrate level in castrated animals. This has also been reported for certain androgen deprived patients (eg voluntarily castrated men, male-to-female transsexuals) who take exogenous estrogens and others who are on high dose antiandrogens which increase endogenous estradiol levels. Estrogen also helps prevent hot flashes and bone mineral loss, which commonly occur with luteinizing hormone-releasing hormone agonist treatment. However, estrogen may cause gynecomastia and increases the risk of breast cancer. Thus, patients with prostate cancer should be informed about the pros and cons of estrogen therapy before starting androgen deprivation therapy. Based on these data estrogen is likely to have maximal benefits in men if initiated simultaneously with androgen deprivation therapy. Because estrogen autoregulates its own receptors, a constant dose of estrogen will not likely produce a constant serum concentration, suggesting that its effectiveness could be optimized if administered cyclically. CONCLUSIONS: Prospective studies on the ability of parenteral estrogen to preserve sexual interest at greater than castrate level in patients with prostate cancer are warranted.

Self-rated health as a tool for estimating health-adjusted life expectancy among patients newly diagnosed with localized prostate cancer: a preliminary study.

PURPOSE: Localized prostate cancer (LPC) patients are faced with numerous treatment options, including observation or watchful waiting. The choice of treatment largely depends on their baseline health-adjusted life expectancy (HALE). By consensus, physicians recommend treatment if the patient's HALE is ten or more years. However, the estimation of HALE is difficult. Although subjective by nature, self-rated health (SRH) is a robust predictor of mortality. We studied the usefulness of SRH in estimating HALE in patients who are considering treatment for LPC. METHODS: A total of 144 LPC patients from a large urology private practice in Norfolk, Virginia, were surveyed before they had chosen a treatment option. RESULTS: HALE determined by SRH correlated well with objective health measures and was higher than age-based life expectancy by an average of 2 years. The observed difference in life expectancy due to SRH adjustment was higher among patients with a better socioeconomic and health profile. CONCLUSIONS: SRH is an easy-to-use indicator of HALE in LPC patients. A table for HALE estimation by age and SRH is provided for men aged 70-80 years. Additional research with larger samples and prospective study designs are needed before the SRH method can be used in primary care and urology settings.

Treatment options for localized prostate cancer.

In the United States, more than 90 percent of prostate cancers are detected by serum prostate-specific antigen testing. Most patients are found to have localized prostate cancer, and most of these patients undergo surgery or radiotherapy. However, many patients have low-risk cancer and can follow an active surveillance protocol instead of undergoing invasive treatments. Active surveillance is a new concept in which low-risk patients are closely followed and proceed to intervention only if their cancer progresses. Clinical guidelines can help in selecting between treatment or active surveillance based on the cancer's stage and grade, the patient's prostate-specific antigen level, and the comorbidity-adjusted life expectancy. Radical prostatectomy or external beam radiation therapy is recommended for higher-risk patients. These treatments are almost equivalent in effectiveness, but have different adverse effect profiles. Brachytherapy is an option for low- and moderate-risk patients. Evidence is insufficient to determine whether laparoscopic or robotic surgery or cryotherapy is superior to open radical prostatectomy.

A history of the Society of Urologic Oncology.

This narrative of the history of the Society of Urologic Oncology (SUO) presents the story of the founding and development of this organization and the creation and establishment of its initiatives and programs. It includes a description of how "Urologic Oncology: Seminars and Original Investigations" came to be designated as its "official journal", thus commemorating the anniversary of the Journal's twenty-five years of publication.

Quality of life after open or robotic prostatectomy, cryoablation or brachytherapy for localized prostate cancer.

PURPOSE: Health related quality of life concerns factor prominently in prostate cancer management. We describe health related quality of life impact and recovery profiles of 4 commonly used operative treatments for localized prostate cancer. MATERIALS AND METHODS: Beginning in February 2000 all patients treated with open radical prostatectomy, robot assisted laparoscopic prostatectomy, brachytherapy or cryotherapy were asked to complete the UCLA-PCI questionnaire before treatment, and at 3, 6, 12, 18, 24, 30 and 36 months after treatment. Outcomes were compared across treatment types with statistical analysis using univariate and multivariate models. RESULTS: A total of 785 patients treated between February 2000 and December 2008 were included in the analysis with a mean followup of 24 months. All health related quality of life domains were adversely affected by all treatments and recovery profiles varied significantly by treatment type. Overall urinary function and bother outcomes scored significantly higher after brachytherapy and cryotherapy compared to open radical prostatectomy and robotic assisted laparoscopic radical prostatectomy. Brachytherapy and cryotherapy had a 3-fold higher rate of return to baseline urinary function compared to open radical prostatectomy and robotic assisted laparoscopic radical prostatectomy. Sexual function and bother scores were highest after brachytherapy, with a 5-fold higher rate of return to baseline function compared to cryotherapy, open radical prostatectomy and robotic assisted laparoscopic radical prostatectomy. All 4 treatments were associated with relatively transient and less pronounced impact on bowel function and bother. CONCLUSIONS: In a study of sequential health related quality of life assessments brachytherapy and cryotherapy were associated with higher urinary function and bother scores compared to open radical prostatectomy and da Vinci prostatectomy. Brachytherapy was associated with higher sexual function and bother scores compared to open radical prostatectomy, robotic assisted laparoscopic radical prostatectomy and cryotherapy.

Development of a scale to assess patient misperceptions about treatment choices for localized prostate cancer.

OBJECTIVES: To develop a questionnaire to assess a patient's knowledge of his cancer, understanding of treatment choices, and judgement of his survival (KUJ) with and without treatment, as treatment for localized prostate cancer (LPC) can lead to urinary, sexual and bowel side-effects and might not improve survival in 75% of patients. PATIENTS AND METHODS: Although >90% of patients in the USA are diagnosed with LPC, approximately 94% of them choose treatment, such that newly diagnosed patients need individualized counselling to address misperceptions about the management of LPC. The internal consistency of an 18-item KUJ scale was evaluated among 184 patients recently diagnosed with LPC at a major urology practice. Principal-component analyses were applied for computing a KUJ index. Logistic regression modelling was used to identify predictors of the KUJ index. RESULTS: Cronbach's alpha for the KUJ scale was 0.76. Nearly half of the patients provided incorrect answers to most KUJ items. Of the patients, 68% had an income of >US$50,000 and 90% had at least high (or secondary) school literacy level. Quality-of-life measures suggested that most patients were physically, mentally and socially healthy. Higher education, income and functional capacity were associated with worse KUJ. CONCLUSION: The KUJ scale is internally consistent and clinicians can use it to identify the educational needs of patients with LPC before treatment selection. Overall, patients who were socioeconomically disadvantaged and those with physical ailments were better informed about the diagnosis, treatment options and prognosis of prostate cancer.

5-α-Reductase inhibitors for prostate cancer chemoprevention: an updated Cochrane systematic review.

OBJECTIVE: • To estimate the benefits and harms of 5-α-reductase inhibitors (5-α-RIs) in preventing prostate cancer. MATERIALS AND METHODS: • We searched MEDLINE and the Cochrane Collaboration Library through June 2010 to identify randomized trials. • We included articles if they examined 5-α-RI vs control, were ≥ 1 year in duration and provided clinical outcomes. • Our primary outcome was prostate cancer period-prevalence 'for-cause'. RESULTS: • Eight studies met inclusion criteria but only the Prostate Cancer Prevention Trial and the Reduction by Dutasteride of Prostate Cancer Events were designed to assess the impact of 5-α-RIs on prostate cancer period-prevalence. The mean age of enrolees was 64 years, 92% were White, and mean PSA level was 3.1 ng/mL. For-cause prostate cancers comprised 54% of all cancers detected in placebo-controlled studies. • Compared with placebo, 5-α-RI resulted in a 25% relative risk (RR) reduction in prostate cancers detected for-cause [RR 0.75, 95% confidence interval (CI) 0.67-0.83; 1.4% absolute risk reduction (3.5% vs 4.9%)]. One BPH trial reported that the risk of prostate cancers detected for-cause was significantly reduced with dutasteride and combined dutasteride plus tamsulosin compared with tamsulosin monotherapy. • Six trials vs placebo assessed prostate cancers detected overall. There was a 26% RR reduction favouring 5-α-RI [RR 0.74, 95% CI 0.55-1.00; 2.9% absolute risk reduction (6.3% vs 9.2%)]. There were reductions across categories of age, race and family history of prostate cancer. • One placebo-controlled trial of men that investigators considered at greater risk for prostate cancer (based on age, elevated PSA level and having a previous suspicion of prostate cancer leading to a prostate biopsy) reported that dutasteride did not reduce prostate cancers detected for-cause based on needle-biopsy but did reduce risk of overall incident prostate cancer detected by biopsy by 23%[RR 0.77, 95% CI 0.70-0.85; absolute reduction 16.1% vs 20.8%]. There were reductions across age, family history of prostate cancer, PSA level, and prostate volume subgroups. • Incidences of erectile dysfunction, ejaculate volume, decreased libido, and gynaecomastia were greater with 5-α-RI vs placebo. CONCLUSIONS: • 5-α-RIs reduce the risk of being diagnosed with prostate cancer among men who are screened regularly for prostate cancer. • Information is inadequate to assess the effect of 5-α-RIs on prostate cancer or all-cause mortality. • 5-α-RIs increase sexual and erectile dysfunction.

Feasibility of using guidelines to choose treatment for prostate cancer.

INTRODUCTION: Treatment for localized prostate cancer (LPC) may not improve survival and commonly impairs health related quality of life. National guidelines provide algorithms to choose between treatment or observation for LPC, but the algorithms require the factoring of the patient's baseline comorbidity adjusted life expectancy (CALE). However, no method is available to estimate CALE of 10 or more years. MATERIALS AND METHODS: A mailed survey was completed by newly diagnosed untreated LPC patients. Their baseline CALE was estimated by weighting their age based life expectancy by quartiles of comorbidity scores, and a national guideline was used to find if treatment or observation was recommended for each patient. Demographic, health and cancer characteristics, and beliefs were compared in patients who chose treatment or observation concordant with the guideline, and those who chose under treatment or over treatment. RESULTS: Of 184 survey participants, 10 chose under treatment, 144 chose concordant treatment, and 30 chose over treatment. Under treatment patients had similar sociodemographic and health characteristics to patients who were concordant. In comparison to concordant patients, over treatment patients were older, had a lower Gleason grade or PSA level, a higher comorbidity score, a lower CALE, and lower scores on the Fear of Cancer Recurrence scale. CONCLUSION: Comorbidity scores can be used to estimate CALE in LPC patients, and estimation of CALE allows the use of guidelines in the choice of treatment. In our study, over treatment occurred more frequently than under treatment. Factors known to limit the survival benefit of treatment were associated with over treatment. Over treatment patients also had lower fear of cancer recurrence.

Open Label Phase II Study of Enzalutamide With Concurrent Administration of Radium 223 Dichloride in Patients With Castration-Resistant Prostate Cancer.

BACKGROUND: Numerous globally approved castration-resistant prostate cancer (CRPC) therapies are available. Enzalutamide and radium 223 (Ra 223) are approved for survival prolongation and ability to delay radiographic progression. Both have markedly different mechanisms of action as well as safety and tolerability profiles. We prospectively investigated their combined safety and tolerability. PATIENTS AND METHODS: EnzaRadiCate, a phase II investigator-initiated trial, enrolled subjects with metastatic CRPC from 4 United States uro-oncology research sites. Safety assessment included physical examination, Eastern Cooperative Oncology Group status, electrocardiogram results, laboratory values, opioid use, radiographic responses, and adverse events (AEs). Quality of life and pain were assessed using the Functional Assessment of Cancer Therapy-Prostate (FACT-P) and the Brief Pain Inventory Short Form (BPI-SF) questionnaires. RESULTS: Thirty-nine subjects completed at least 2 cycles of Ra 223, and 34 (87%) completed all 6 cycles through and the EOT visit. Sixty-one treatment-related AEs were reported by 53.8% of subjects. The most frequent AEs were fatigue (25.6%), nausea (17.9%), and anemia (12.8%). Three subjects experienced non-treatment-related serious AEs. One subject was hospitalized for sepsis, and 2 deaths were attributed to disease progression. Fifteen (38.5%) subjects demonstrated radiographic progression, and 24 (61.5%) subjects had no radiographic progression. CONCLUSIONS: Safety and tolerability of combinatorial use of enzalutamide and Ra 223 were demonstrated. Subjects experienced improvements in quality of life and pain, without unexpected toxicities nor increases in falls, fractures, or deaths. Phase III combination trials of Ra 223 with novel oral hormonal agents are ongoing to further evaluate radiographic progression and overall survival benefit.

Survival of African-American and Caucasian men after sipuleucel-T immunotherapy: outcomes from the PROCEED registry.

PURPOSE: African Americans experience greater prostate cancer risk and mortality than do Caucasians. An analysis of pooled phase III data suggested differences in overall survival (OS) between African American and Caucasian men receiving sipuleucel-T. We explored this in PROCEED (NCT01306890), an FDA-requested registry in over 1900 patients with metastatic castration-resistant prostate cancer (mCRPC) treated with sipuleucel-T. PATIENTS AND METHODS: OS for patients who received ≥1 sipuleucel-T infusion was compared between African American and Caucasian men using an all patient set and a baseline prostate-specific antigen (PSA)-matched set (two Caucasians to every one African American with baseline PSAs within 10% of each other). Univariable and multivariable analyses were conducted. Survival data were examined using Kaplan-Meier and Cox proportional hazard methodologies. RESULTS: Median follow-up was 46.6 months. Overall survival differed between African American and Caucasian men with hazard ratios (HR) of 0.81 (95% confidence interval [CI]: 0.68-0.97, P = 0.03) in the all patient set and 0.70 (95% CI: 0.57-0.86, P < 0.001) in the PSA-matched set. Median OS was longer in African Americans than in Caucasian men for both analysis sets, e.g., 35.3 and 25.8 months, respectively, in the PSA-matched set. Similar results were observed in the all patient set. Differences were larger when treatment began at lower baseline PSA; curves were more similar among patients with higher baseline PSA. In patients with baseline PSA below the median, the HR was 0.52 (95% CI: 0.37-0.72, P < 0.001), with median OS of 54.3 versus 33.4 months. Known prognostic factors and African American race (multivariable analyses; HR: 0.60, 95% CI: 0.48-0.74, P < 0.001) were independently associated with OS. Use of post-sipuleucel-T anticancer interventions was balanced between races. CONCLUSION: In this exploratory analysis of a registry including nearly 12% African American men with mCRPC, OS was significantly different between African Americans and Caucasians, indicating further research is warranted.