Emerging racial disparities among Medicare beneficiaries and Veterans with metastatic castration-sensitive prostate cancer.

BACKGROUND: Previous studies have shown that Black men receive worse prostate cancer care than White men. This has not been explored in metastatic castration-sensitive prostate cancer (mCSPC) in the current treatment era. METHODS: We evaluated treatment intensification (TI) and overall survival (OS) in Medicare (2015-2018) and Veterans Health Administration (VHA; 2015-2019) patients with mCSPC, classifying first-line mCSPC treatment as androgen deprivation therapy (ADT) + novel hormonal therapy; ADT + docetaxel; ADT + first-generation nonsteroidal antiandrogen; or ADT alone. RESULTS: We analyzed 2226 Black and 16,071 White Medicare, and 1020 Black and 2364 White VHA patients. TI was significantly lower for Black vs White Medicare patients overall (adjusted odds ratio [OR] 0.68; 95% confidence interval [CI] 0.58-0.81) and without Medicaid (adjusted OR 0.70; 95% CI 0.57-0.87). Medicaid patients had less TI irrespective of race. OS was worse for Black vs White Medicare patients overall (adjusted hazard ratio [HR] 1.20; 95% CI 1.09-1.31) and without Medicaid (adjusted HR 1.13; 95% CI 1.01-1.27). OS was worse in Medicaid vs without Medicaid, with no significant OS difference between races. TI was significantly lower for Black vs White VHA patients (adjusted OR 0.75; 95% CI 0.61-0.92), with no significant OS difference between races. CONCLUSIONS: Guideline-recommended TI was low for all patients with mCSPC, with less TI in Black patients in both Medicare and the VHA. Black race was associated with worse OS in Medicare but not the VHA. Medicaid patients had less TI and worse OS than those without Medicaid, suggesting poverty and race are associated with care and outcomes.

Toward Informed Selection and Interpretation of Clinical Genomic Tests in Prostate Cancer.

Clinical genomic testing of patient germline, tumor tissue, or plasma cell-free DNA can enable a personalized approach to cancer management and treatment. In prostate cancer (PCa), broad genotyping tests are now widely used to identify germline and/or somatic alterations in BRCA2 and other DNA damage repair genes. Alterations in these genes can confer cancer sensitivity to poly (ADP-ribose) polymerase inhibitors, are linked with poor prognosis, and can have potential hereditary cancer implications for family members. However, there is huge variability in genomic tests and reporting standards, meaning that for successful implementation of testing in clinical practice, end users must carefully select the most appropriate test for a given patient and critically interpret the results. In this white paper, we outline key pre- and post-test considerations for choosing a genomic test and evaluating reported variants, specifically for patients with advanced PCa. Test choice must be based on clinical context and disease state, availability and suitability of tumor tissue, and the genes and regions that are covered by the test. We describe strategies to recognize false positives or negatives in test results, including frameworks to assess low tumor fraction, subclonal alterations, clonal hematopoiesis, and pathogenic versus nonpathogenic variants. We assume that improved understanding among health care professionals and researchers of the nuances associated with genomic testing will ultimately lead to optimal patient care and clinical decision making.

Low-dose Paclitaxel with Pembrolizumab Enhances Clinical and Immunologic Responses in Platinum-refractory Urothelial Carcinoma.

PURPOSE: Single-agent checkpoint inhibition is effective in a minority of patients with platinum-refractory urothelial carcinoma; therefore, the efficacy of combining low-dose paclitaxel with pembrolizumab was tested. MATERIALS AND METHODS: This was a prospective, single-arm phase II trial with key inclusion criteria of imaging progression within 12 months of platinum therapy and Eastern Cooperative Oncology Group ≤1. Treatment was pembrolizumab 200 mg day 1 and paclitaxel 80 mg/m2 days 1 and 8 of a 21-day cycle for up to eight cycles unless progression or unacceptable adverse events (AE). The primary endpoint was overall response rate (ORR) with overall survival (OS), 6-month progression-free survival (PFS), and safety as key secondary endpoints. Change in circulating immune cell populations, plasma, and urinary miRs were evaluated. RESULTS: Twenty-seven patients were treated between April 2016 and June 2020, with median follow-up of 12.4 months. Baseline median age was 68 years, with 81% men and 78% non-Hispanic White. ORR was 33% by intention to treat and 36% in imaging-evaluable patients with three complete responses. Six-month PFS rate was 48.1% [95% confidence interval (CI): 28.7-65.2] and median OS 12.4 months (95% CI: 8.7 months to not reached). Common ≥ grade 2 possibly-related AEs were anemia, lymphopenia, hyperglycemia, and fatigue; grade 3/4 AEs occurred in 56%, including two immune-mediated AEs (pneumonitis and nephritis). Responding patients had a higher percentage of circulating CD4+IFNγ+ T cells. Levels of some miRs, including plasma miR 181 and miR 223, varied in responders compared with nonresponders. CONCLUSIONS: The addition of low-dose paclitaxel to pembrolizumab is active and safe in platinum-refractory urothelial carcinoma. SIGNIFICANCE: We found that combining pembrolizumab with low-dose paclitaxel may be effective in patients with urothelial carcinoma progressing on platinum chemotherapy, with favorable safety profiles.

Genomic classifiers and prognosis of localized prostate cancer: a systematic review.

BACKGROUND: Refinement of the risk classification for localized prostate cancer is warranted to aid in clinical decision making. A systematic analysis was undertaken to evaluate the prognostic ability of three genomic classifiers, Decipher, GPS, and Prolaris, for biochemical recurrence, development of metastases and prostate cancer-specific mortality in patients with localized prostate cancer. METHODS: Data sources: MEDLINE, Embase, and Web of Science were queried for reports published from January 2010 to April 2022. STUDY SELECTION: prospective or retrospective studies reporting prognosis for patients with localized prostate cancer. DATA EXTRACTION: relevant data were extracted into a customized database by one researcher with a second overreading. Risk of bias was assessed using a validated tool for prognostic studies, Quality in Prognosis Studies (QUIPS). Disagreements were resolved by consensus or by input from a third reviewer. We assessed the certainty of evidence by GRADE incorporating adaptation for prognostic studies. RESULTS: Data synthesis: a total of 39 studies (37 retrospective) involving over 10,000 patients were identified. Twenty-two assessed Decipher, 5 GPS, and 14 Prolaris. Thirty-four studies included patients who underwent prostatectomy. Based on very low to low certainty of evidence, each of the three genomic classifiers modestly improved upon the prognostic ability for biochemical recurrence, development of metastases, and prostate cancer-specific mortality compared to standard clinical risk-classification schemes. LIMITATIONS: downgrading of confidence in the evidence stemmed largely from bias due to the retrospective nature of the studies, heterogeneity in treatment received, and era in which patients were treated (i.e., prior to the 2000s). CONCLUSIONS: Genomic classifiers provide a small but consistent improvement upon the prognostic ability of clinical classification schemes, which may be helpful when treatment decisions are uncertain. However, evidence from current management-era data and of the predictive ability of these tests is needed.

Marital Status, Living Arrangement, and Survival among Individuals with Advanced Prostate Cancer in the International Registry for Men with Advanced Prostate Cancer.

BACKGROUND: Studies have shown improved survival among individuals with cancer with higher levels of social support. Few studies have investigated social support and overall survival (OS) in individuals with advanced prostate cancer in an international cohort. We investigated the associations of marital status and living arrangements with OS among individuals with advanced prostate cancer in the International Registry for Men with Advanced Prostate Cancer (IRONMAN). METHODS: IRONMAN is enrolling participants diagnosed with advanced prostate cancer (metastatic hormone-sensitive prostate cancer, mHSPC; castration-resistant prostate cancer, CRPC) from 16 countries. Participants in this analysis were recruited between July 2017 and January 2023. Adjusting for demographics and tumor characteristics, the associations were estimated using Cox regression and stratified by disease state (mHSPC, CRPC), age (<70, ≥70 years), and continent of enrollment (North America, Europe, Other). RESULTS: We included 2,119 participants with advanced prostate cancer, of whom 427 died during up to 5 years of follow-up (median 6 months). Two-thirds had mHSPC. Most were married/in a civil partnership (79%) and 6% were widowed. Very few married participants were living alone (1%), while most unmarried participants were living alone (70%). Married participants had better OS than unmarried participants [adjusted HR: 1.44; 95% confidence interval (CI): 1.02-2.02]. Widowed participants had the worst survival compared with married individuals (adjusted HR: 1.89; 95% CI: 1.22-2.94). CONCLUSIONS: Among those with advanced prostate cancer, unmarried and widowed participants had worse OS compared with married participants. IMPACT: This research highlighted the importance of social support in OS within this vulnerable population.

Transcriptomic Signatures Associated With Outcomes in Recurrent Prostate Cancer Treated With Salvage Radiation, Androgen-Deprivation Therapy, and Enzalutamide: Correlative Analysis of the STREAM Trial.

PURPOSE: Men with rising prostate-specific antigen (PSA) after radical prostatectomy (RP) may progress despite radiation and androgen-deprivation therapy (ADT). Tissue-based transcriptomic signatures can identify who may benefit from a more aggressive systemic approach. METHODS: We performed a retrospective analysis of a prospective phase II multicenter trial of enzalutamide, ADT, and salvage radiotherapy in men with rising PSA after RP. Tumor tissue was analyzed using the Decipher platform for gene expression, including a novel prostate subtyping classifier, PTEN loss, homologous recombination deficiency (HRD), and ADT response. Cox models were used to associate signature scores with progression-free survival (PFS). RESULTS: Of the 38 men enrolled, 31 had tissue with sufficient-quality RNA for genomic analysis. Luminal differentiated (LD) subtype tumors had the longest 3-year PFS at 89% compared with 19% in the luminal proliferating subtype. Men with signatures of PTEN loss (hazard ratio [HR], 1.32; 95% CI, 1.07 to 1.64; P = .01) or HRD (HR, 1.21; 95% CI, 1.05 to 1.39; P = .009) had worse PFS, while those with higher ADT response signature scores (HR, 0.75; 95% CI, 0.61 to 0.94; P = .01) were associated with improved PFS. Analysis of these signatures in a large cohort (n = 5,330) of RP samples from patients with biochemical recurrence found that these signatures provide complementary information related to outcomes with salvage radiation. CONCLUSION: Despite aggressive systemic therapy with salvage radiation, nearly 50% of high-risk men relapse within 3 years. We show that LD and higher ADT sensitivity tumors had favorable outcomes. Those with a luminal proliferating subtype, PTEN loss, and/or HRD signatures had poor outcomes despite ADT/radiation and enzalutamide and may benefit from alternative approaches.

Study design and methods for the pilot study of muscadine grape extract supplement to improve fatigue among older adult cancer survivors (FOCUS) trial.

INTRODUCTION: Fatigue is a prevalent symptom among both cancer survivors and older adults. Negative consequences of fatigue include increased sedentary behavior, decreased physical activity and function, and lower quality of life. Few pharmacologic interventions improve fatigue. Our preclinical and clinical data show promising effects of a muscadine grape extract supplement (MGES) on oxidative stress, mitochondrial bioenergetics, the microbiome, and the symptom of fatigue. This pilot study seeks to translate these observations to cancer survivorship by testing the preliminary effect of MGE supplementation on older adult cancer survivors with self-reported fatigue. MATERIALS AND METHODS: We designed a double-blinded placebo-controlled pilot study to evaluate preliminary efficacy of MGE supplementation versus placebo on fatigue among older adult cancer survivors (aged ≥65 years) who report baseline fatigue. Sixty-four participants will be enrolled and randomized 1:1 to twice daily MGES (four tablets twice daily) versus placebo for 12 weeks. The primary outcome is change in Patient-Reported Outcomes Measurement Information System (PROMIS) Fatigue score from baseline to 12 weeks. Secondary outcomes are change in self-reported physical function, physical fitness (6-min walk test), self-reported physical activity, global quality of life (QOL), and the Fried frailty index. Correlative biomarker assays will assess changes in 8-hydroxy-2 deoxyguanosine, peripheral blood mitochondrial function, inflammatory markers, and the gut microbiome. DISCUSSION: This pilot study builds on preclinical and clinical observations to estimate effects of MGE supplementation on fatigue, physical function, QOL, and biologic correlates in older adult cancer survivors. Trial registration #: CT.govNCT04495751; IND 152908.

Feasibility of home-based exercise training in men with metastatic castration-resistant prostate cancer.

BACKGROUND: Home-based training increases accessibility to exercise and mitigates the side effects of hormone therapy for prostate cancer (PC). However, it is unknown if men with more advanced disease are willing to partake in such interventions. PURPOSE: To determine the feasibility of a home-based exercise intervention in men with metastatic castration-resistant prostate cancer (mCRPC). METHODS: mCRPC patients on androgen receptor signaling inhibitors (ARSI) were prescribed a 12-week, home-based exercise intervention using resistance bands and walking. Feasibility was assessed using recruitment, retention, adherence, and outcome capture. Physiological changes and patient reported outcomes were assessed before and after the intervention. RESULTS: Of the 62 referrals, 47 were eligible with 22 men performing baseline testing (47% recruitment rate) and 16 completing the intervention (73% retention). Task completion was >86% for all physiological tests. Walking adherence was 80% and resistance training was 63%, the latter falling short of the study target (75%). Training increased thigh muscle cross-sectional area by 22%, time to exhaustion by 19% (both p < 0.05) and peak oxygen uptake by 6% (p = 0.057). Improvements in short physical performance battery scores and 400 m walk demonstrated moderate effect sizes that did not reach significance. CONCLUSIONS: Home-based exercise is feasible during ARSI treatment for mCRPC. Greater endurance capacity and localized hypertrophy appear as the primary improvements following training. These preliminary findings suggest home-based training may increase exercise accessibility, with important lessons that will inform subsequent trials investigating the efficacy of home-based exercise interventions during mCRPC.

Impact of Race on Outcomes of High-Risk Patients With Prostate Cancer Treated With Moderately Hypofractionated Radiotherapy in an Equal Access Setting.

Background: Moderately hypofractionated radiotherapy (MHRT) is an accepted treatment for localized prostate cancer; however, limited MHRT data address high-risk prostate cancer (HRPC) and/or African American patients. We report clinical outcomes and toxicity profiles for individuals with HRPC treated in an equal access system. Methods: We identified patients with HRPC treated with MHRT at a US Department of Veterans Affairs referral center. Exclusion criteria included < 12 months follow-up and elective nodal irradiation. MHRT included 70 Gy over 28 fractions or 60 Gy over 20 fractions. Acute and late gastrointestinal (GI) and genitourinary (GU) toxicities were graded using Common Terminology Criteria for Adverse Events, version 5.0. Clinical endpoints, including biochemical recurrence-free survival (BRFS), distant metastases-free survival (DMFS), overall survival (OS), and prostate cancer-specific survival (PCSS) were estimated using Kaplan-Meier methods. Clinical outcomes, acute toxicity, and late toxicity-free survival were compared between African American and White patients with logistic regression and log-rank testing. Results: Between November 2008 and August 2018, 143 patients with HRPC were treated with MHRT and followed for a median of 38.5 months; 82 (57%) were African American and 61 were White patients. Concurrent androgen deprivation therapy (ADT) was provided for 138 (97%) patients for a median duration of 24 months. No significant differences between African American and White patients were observed for 5-year OS (73% [95% CI, 58%-83%] vs 77% [95% CI, 60%-97%]; P = .55), PCSS (90% [95% CI, 79%-95%] vs 87% [95 % CI, 70%-95%]; P = .57), DMFS (91% [95% CI, 80%-96%] vs 81% [95% CI, 62%-91%]; P = .55), or BRFS (83% [95% CI, 70%-91%] vs 71% [95% CI, 53%-82%]; P = .57), respectively. Rates of acute grade 3+ GU and GI were low overall (4% and 1%, respectively). Late toxicities were similarly favorable with no significant differences by race. Conclusions: Individuals with HRPC treated with MHRT in an equal access setting demonstrated favorable clinical outcomes that did not differ by race, alongside acceptable rates of acute and late toxicities.

Safety, tolerability and efficacy of agonist anti-CD27 antibody (varlilumab) administered in combination with anti-PD-1 (nivolumab) in advanced solid tumors.

BACKGROUND: Phase 1/2 dose-escalation and expansion study evaluating varlilumab, a fully human agonist anti-CD27 mAb, with nivolumab in anti-PD-1/L1 naïve, refractory solid tumors. METHODS: Phase 1 evaluated the safety of varlilumab (0.1-10 mg/kg) with nivolumab (3 mg/kg) administered once every 2 weeks. Phase 2 evaluated varlilumab regimens (3 mg/kg once every 2 weeks, 3 mg/kg once every 12 weeks, and 0.3 mg/kg once every 4 weeks) with nivolumab 240 mg once every 2 weeks in tumor-specific cohorts. Primary objective was safety; key clinical endpoints included objective response rate (ORR) and overall survival rate at 12 months (OS12) (glioblastoma (GBM) only). Exploratory objectives included determination of effects on peripheral blood and intratumoral immune signatures. RESULTS: 175 patients were enrolled (36 in phase 1 and 139 in phase 2). Phase 1 dose-escalation proceeded to the highest varlilumab dose level without determining a maximum tolerated dose. In phase 2, ORR were ovarian 12.5%, squamous cell carcinoma of the head and neck 12.5%, colorectal cancer 5%, and renal cell carcinoma 0%; GBM OS12 was 40.9%. Increased tumor PD-L1 and intratumoral T cell infiltration were observed in ovarian cancer patients, with increases of ≥5% associated with better progression-free survival. The most common treatment related adverse events were fatigue (18%), pruritus (16%), and rash (15%). CONCLUSION: Varlilumab and nivolumab were well tolerated, without significant toxicity beyond that expected for each agent alone. Clinical activity was observed in patients that are typically refractory to anti-PD-1 therapy, however, overall was not greater than expected for nivolumab monotherapy. Treatment was associated with proinflammatory changes in the tumor microenvironment, particularly in ovarian cancer where the changes were associated with better clinical outcomes. TRIAL REGISTRATION NUMBER: NCT02335918.

Homologous Recombination Repair Gene Variants and Outcomes Among Patients With Prostate Cancer Treated With Poly (ADP-ribose) Polymerase Inhibitors.

PURPOSE: Poly ADP-ribose polymerase inhibitors (PARPi) are used for patients with advanced prostate cancer bearing alterations in homologous recombination repair (HRR) genes. We sought to characterize HRR gene variants and describe real-world outcomes for patients on PARPi. METHODS: The US Department of Veterans Affairs' National Precision Oncology Program's database was reviewed to identify patients who underwent somatic DNA sequencing and were prescribed a PARPi before May 15, 2020. Somatic and germline variants within HRR genes were reported, and pathogenicity was reviewed via OncoKB. In patients treated with PARPi for > 4 weeks, the rate of those achieving a 30% decrease in prostate-specific antigen (PSA30) and composite progression-free survival (PFS) were compared between patients bearing pathogenic variants of BRCA2 and patients without these variants using Mann-Whitney and log-rank tests, respectively. RESULTS: Forty-eight patients bearing 67 total HRR gene variants were prescribed PARPi for prostate cancer. Twenty-one patients (43.8%) were found to have at least one pathogenic HRR gene variant. Eight (16.6%) were referred to genetic counseling, and five (10.4%) were ultimately confirmed with germline variants. The median PFS was 4.0 months, and PSA30 was 25.6% (11 of 43) for all 43 evaluable patients. Patients with pathogenic BRCA2 variants (n = 13) had higher PSA30 (69.2% v 4.0%; P < .001) and longer PFS (7.2 v 2.8 months; P = .0291) than those without. CONCLUSION: In a real-world setting, heavily pretreated patients with prostate cancer and pathogenic BRCA2 variants have a significant PSA response rate and a PFS > 7 months with PARPi. This work emphasizes the importance of determining pathogenicity and origin of HRR alterations to better inform clinical treatment decisions and highlights the need for provider education and other decision support tools.

IL-7 expands lymphocyte populations and enhances immune responses to sipuleucel-T in patients with metastatic castration-resistant prostate cancer (mCRPC).

BACKGROUND: Sipuleucel-T (sip-T) is a Food and Drug Administration (FDA)-approved autologous cellular immunotherapy for metastatic castration-resistant prostate cancer (mCRPC). We hypothesized that combining sip-T with interleukin (IL)-7, a homeostatic cytokine that enhances both B and T cell development and proliferation, would augment and prolong antigen-specific immune responses against both PA2024 (the immunogen for sip-T) and prostatic acid phosphatase (PAP). METHODS: Fifty-four patients with mCRPC treated with sip-T were subsequently enrolled and randomized 1:1 into observation (n=26) or IL-7 (n=28) arms of a phase II clinical trial (NCT01881867). Recombinant human (rh) IL-7 (CYT107) was given weekly×4. Immune responses were evaluated using flow cytometry, mass cytometry (CyTOF), interferon (IFN)-γ ELISpot, 3H-thymidine incorporation, and ELISA. RESULTS: Treatment with rhIL-7 was well tolerated. For the rhIL-7-treated, but not observation group, statistically significant lymphocyte subset expansion was found, with 2.3-2.6-fold increases in CD4+T, CD8+T, and CD56bright NK cells at week 6 compared with baseline. No significant differences in PA2024 or PAP-specific T cell responses measured by IFN-γ ELISpot assay were found between rhIL-7 and observation groups. However, antigen-specific T cell proliferative responses and humoral IgG and IgG/IgM responses significantly increased over time in the rhIL-7-treated group only. CyTOF analyses revealed pleiotropic effects of rhIL-7 on lymphocyte subsets, including increases in CD137 and intracellular IL-2 and IFN-γ expression. While not powered to detect clinical outcomes, we found that 31% of patients in the rhIL-7 group had prostate specific antigen (PSA) doubling times of >6 months, compared with 14% in the observation group. CONCLUSIONS: Treatment with rhIL-7 led to a significant expansion of CD4+ and CD8+ T cells, and CD56bright natural killer (NK) cells compared with observation after treatment with sip-T. The rhIL-7 treatment also led to improved antigen-specific humoral and T cell proliferative responses over time as well as to increased expression of activation markers and beneficial cytokines. This is the first study to evaluate the use of rhIL-7 after sip-T in patients with mCRPC and demonstrates encouraging results for combination approaches to augment beneficial immune responses.

A prospective trial of abiraterone acetate plus prednisone in Black and White men with metastatic castrate-resistant prostate cancer.

BACKGROUND: Retrospective analyses of randomized trials suggest that Black men with metastatic castration-resistant prostate cancer (mCRPC) have longer survival than White men. The authors conducted a prospective study of abiraterone acetate plus prednisone to explore outcomes by race. METHODS: This race-stratified, multicenter study estimated radiographic progression-free survival (rPFS) in Black and White men with mCRPC. Secondary end points included prostate-specific antigen (PSA) kinetics, overall survival (OS), and safety. Exploratory analysis included genome-wide genotyping to identify single nucleotide polymorphisms associated with progression in a model incorporating genetic ancestry. One hundred patients self-identified as White (n = 50) or Black (n = 50) were enrolled. Eligibility criteria were modified to facilitate the enrollment of individual Black patients. RESULTS: The median rPFS for Black and White patients was 16.6 and 16.8 months, respectively; their times to PSA progression (TTP) were 16.6 and 11.5 months, respectively; and their OS was 35.9 and 35.7 months, respectively. Estimated rates of PSA decline by ≥50% in Black and White patients were 74% and 66%, respectively; and PSA declines to <0.2 ng/mL were 26% and 10%, respectively. Rates of grade 3 and 4 hypertension, hypokalemia, and hyperglycemia were higher in Black men. CONCLUSIONS: Multicenter prospective studies by race are feasible in men with mCRPC but require less restrictive eligibility. Despite higher comorbidity rates, Black patients demonstrated rPFS and OS similar to those of White patients and trended toward greater TTP and PSA declines, consistent with retrospective reports. Importantly, Black men may have higher side-effect rates than White men. This exploratory genome-wide analysis of TTP identified a possible candidate marker of ancestry-dependent treatment outcomes.

Phase I Study of Muscadine Grape Extract for Patients With Advanced Cancer.

OBJECTIVE: Preclinical studies with muscadine grape extract (MGE) show antitumor activity and decreased systemic inflammation. This phase I study (NCT02583269) assessed safety and tolerability of a proprietary MGE preparation in patients with advanced solid tumors. METHODS: Patients with metastatic or unresectable cancers who were progressing on standard therapies were assigned to MGE in a standard 3+3 design. Five dose levels were tested (320 to 1600 mg total phenolics/d). Safety and maximum-tolerated dose were assessed after 4 weeks. Patients were evaluated for response at 8 weeks and continued on MGE if clinically stable. Secondary outcomes were response, survival, adherence, fatigue, and quality of life (QOL). RESULTS: In total, 23 patients (lung, n=7; gastrointestinal, n=7; genitourinary, n=6; other, n=3) received MGE capsules by mouth twice daily. The cohort [median age 72 years, 48% Eastern Cooperative Oncology Group (ECOG) 2] was heavily pretreated. After 4 weeks on MGE, possibly attributable adverse events grade 2 or higher were fatigue (n=1), decreased lymphocyte count (n=1), and constipation (n=2), including 1 dose-limiting toxicity for grade 3 constipation. Maximum-tolerated dose was not reached. No partial responses were observed. Median time on therapy was 8 weeks, with 29% of patients treated beyond 16 weeks and a median overall survival of 7.2 months. QOL and fatigue levels were stable from baseline to 8 weeks. Higher MGE dose was correlated with improvement in self-reported physical well-being QOL at 8 weeks (r=0.6; P=0.04). CONCLUSIONS: MGE is safe and well-tolerated in heavily pretreated and older cancer patients.  The potential anticancer properties and the effects of MGE on physical well-being and QOL metrics will be evaluated in future studies.

Body composition, physical function and quality of life in healthy men and across different stages of prostate cancer.

BACKGROUND: Androgen deprivation therapy (ADT) for prostate cancer (PC) has detrimental effects on physical function and quality of life (QoL), but the addition of androgen receptor signalling inhibitors (ARSI) on these outcomes is unclear. PURPOSE: To compare body composition, physical function, and QoL across progressive stages of PC and non-cancer controls (CON). METHODS: In men with hormone sensitive PC (HSPC, n = 43) or metastatic castration-resistant PC (mCRPC, n = 22) or CON (n = 37), relative and absolute lean and fat mass, physical function (6 m walk, chair stands, timed up and go [TUG], stair climb), and QoL were determined. RESULTS: Relative body composition differed amongst all groups, along with ~39% greater absolute fat mass in mCRPC vs. CON. TUG and chair stands were ~71% and ~33% slower in mCRPC compared to both CON and HSPC, whereas stair climb was ~29% and 6 m walk was ~18% slower in mCRPC vs. CON. Relative body composition was correlated with physical function (r = 0.259-0.385). Clinically relevant differences for mCRPC were observed for overall QoL and several subscales vs. CON, although body composition and physical function did not influence QoL. CONCLUSIONS: PC progression is associated with deteriorations in body composition and physical function. As ADT length was similar between groups, ARSI use for mCRPC likely contributed in part to these changes. Given the difficulties of improving lean mass during ADT, interventions that reduce adiposity may lessen the side effects of hormone therapy.

Management of men with metastatic castration-resistant prostate cancer following potent androgen receptor inhibition: a review of novel investigational therapies.

BACKGROUND: Androgen-targeted therapy and chemotherapy are currently the mainstay of treatment in metastatic castration resistant prostate cancer (mCRPC). When progression occurs despite these therapeutic strategies, additional FDA-approved treatment options are lacking. However, there is a vast amount of emerging data surrounding novel investigational therapies in this space. METHODS: We reviewed and summarized the body of literature surrounding the current treatment options for mCRPC. Medline and Pubmed as well as abstracts from international congresses were utilized to gather relevant literature surrounding investigational treatment of mCRPC. We highlight the results of recent trials investigating the use of novel strategies to treat mCRPC. RESULTS: Androgen-targeted therapy and chemotherapy will remain foundational in the treatment of mCRPC. However, heavily pretreated patients who have developed resistance may benefit from novel therapeutic strategies. The use of poly(adenosine diphosphate [ADP]-ribose) polymerase inhibitors (PARPi) has now gained FDA approval for patients with homologous recombination repair (HRR) gene mutations. Novel androgen receptor (AR) degraders and the use of radioligand therapy (RLT) with Lu-PSMA-617 (Lu-PSMA) are under investigation. Immune-directed therapies, including programmed death (PD-1) inhibition, bi-specific T-cell engager (BiTE) technology, and chimeric antigen receptor (CAR) T-cell therapy, have shown promise in early phase trials. Further understanding of resistance mechanisms has led to additional therapeutic targets, including targeting the PI3K-Akt-mTOR pathway and enhancer of zester homolog 2 (EZH2). CONCLUSIONS: Based on our review of the literature, exciting new therapeutic strategies exist for the treatment of mCRPC. In particular, PARPi, AR degraders, PSMA-targeted therapies, immune-directed therapies, and agents targeting resistance mechanisms as monotherapy or in combination could improve patient outcomes. Additional data from randomized trials are necessary to understand the efficacy and tolerability of these treatment strategies.

Phase II Trial of Enzalutamide and Androgen Deprivation Therapy with Salvage Radiation in Men with High-risk Prostate-specific Antigen Recurrent Prostate Cancer: The STREAM Trial.

BACKGROUND: Salvage external beam radiotherapy (RT) with androgen deprivation therapy (ADT) improves survival over RT in men with prostate cancer (PC) and rising prostate-specific antigen (PSA) levels after radical prostatectomy (RP). OBJECTIVE: To investigate the safety and efficacy of enzalutamide concurrent with salvage RT and ADT. DESIGN, SETTING, AND PARTICIPANTS: This was a three-center prospective phase 2 single-arm trial (NCT02057939) of men with Gleason 7-10 PC and PSA recurrence within 4 yr of RP ranging from 0.2 to 4.0 ng/dl, no prior hormonal therapy, and no radiographic evidence of metastases. We enrolled 38 men; 37 completed therapy and were evaluable with testosterone recovery at 2 yr. INTERVENTION: Six months of ADT with 160 mg/d enzalutamide and 66 Gy RT to the prostate bed. OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS: The primary endpoint was improved 2-yr progression-free survival (PFS) over historical controls. Secondary objectives included 3-yr PFS, safety, and patient-reported quality of life (QOL). RESULTS AND LIMITATIONS: The primary endpoint of 2-yr PFS was 65% (95% confidence interval [CI]: 47, 78) versus 51% (95% CI: 33, 67) in a trial of men with similar eligibility treated with salvage RT and adjuvant docetaxel. The 3-yr PFS was 53%. Eleven (29%) men experienced G3 toxicities, and there were no G4-5 or unexpected toxicities. QOL data suggest modest worsening of bowel, bladder, and hormonal symptoms at 3 mo, with recovery by 24 mo in most men. CONCLUSIONS: Salvage RT with enzalutamide and ADT following RP for men with PSA recurrent high-risk PC is safe and demonstrates encouraging efficacy, warranting prospective controlled phase 3 trials of ADT with or without potent androgen receptor inhibition in this curative-intent setting. PATIENT SUMMARY: Addition of 6 mo of oral daily enzalutamide to standard salvage radiation and hormone therapy is safe and may improve prostate cancer remission rates at 2 and 3 yr.

Racial Disparity in Response to Prostate Cancer Systemic Therapies.

PURPOSE OF REVIEW: In this review, we aim to describe racial differences in response to treatment for metastatic castration-resistant prostate cancer (mCRPC). RECENT FINDINGS: Recent data suggests that, despite higher risk features, African Americans may respond better than Caucasians to systemic therapies for advanced prostate cancer. This improved response is not limited to one class of drugs but can be seen with androgen-pathway directed therapies, chemotherapy, bone-targeted therapy, and immunotherapy. The mechanisms for this are being further explored. African Americans may respond better to mCRPC treatments but validation in prospective clinical trials is needed.

Trajectories in muscular strength and physical function among men with and without prostate cancer in the health aging and body composition study.

OBJECTIVES: To examine and compare changes in strength and physical function from pre- to post-diagnosis among men with prostate cancer (PC, [cases]) and matched non-cancer controls identified from the Health, Aging and Body Composition (Health ABC) study. MATERIALS AND METHODS: We conducted a longitudinal analysis of 2 strength and 3 physical function-based measures among both cases and controls, identified from a large cohort of community living older adults enrolled in the Health ABC study. We plotted trajectories for each measure and compared cases vs. controls from the point of diagnosis onwards using mixed-effects regression models. For cases only, we examined predictors of poor strength or physical function. RESULTS: We identified 117 PC cases and 453 matched non-cancer controls (50% African Americans). At baseline, there were no differences between cases and controls in demographic factors, comorbidities or self-reported physical function; however, cases had slightly better grip strength (44.6 kg vs. 41.0 kg, p<0.01), quadriceps strength (360.5 Nm vs. 338.7 Nm, p = 0.02) and Health ABC physical performance battery scores (2.4 vs. 2.3, p = 0.01). All men experienced similar declines in strength and physical function over an equivalent amount of time. The loss of quad strength was most notable, with losses of nearly two-thirds of baseline strength over approximately 7 years of follow up. CONCLUSIONS: Among both cases and controls, strength and physical function decline with increasing age. The largest declines were seen in lower body strength. Regular assessments should guide lifestyle interventions that can offset age- and treatment-related declines among men with PC.

Syntaxin 6-mediated exosome secretion regulates enzalutamide resistance in prostate cancer.

Prostate cancer (PCa) deaths are typically the result of metastatic castration-resistant PCa (mCRPC). Recently, enzalutamide (Enz), an oral androgen receptor inhibitor, was approved for treating patients with mCRPC. Invariably, all PCa patients eventually develop resistance against Enz. Therefore, novel strategies aimed at overcoming Enz resistance are needed to improve the survival of PCa patients. The role of exosomes in drug resistance has not been fully elucidated in PCa. Therefore, we set out to better understand the exosome's role in the mechanism underlying Enz-resistant PCa. Results showed that Enz-resistant PCa cells (C4-2B, CWR-R1, and LNCaP) secreted significantly higher amounts of exosomes (2-4 folds) compared to Enz-sensitive counterparts. Inhibition of exosome biogenesis in resistant cells by GW4869 and dimethyl amiloride strongly decreased their cell viability. Mechanistic studies revealed upregulation of syntaxin 6 as well as its increased colocalization with CD63 in Enz-resistant PCa cells compared to Enz-sensitive cells. Syntaxin 6 knockdown by specific small interfering RNAs in Enz-resistant PCa cells (C4-2B and CWR-R1) resulted in reduced cell number and increased cell death in the presence of Enz. Furthermore, syntaxin 6 knockdown significantly reduced the exosome secretion in both Enz-resistant C4-2B and CWR-R1 cells. The Cancer Genome Atlas analysis showed increased syntaxin 6 expressions associated with higher Gleason score and decreased progression-free survival in PCa patients. Importantly, IHC analysis showed higher syntaxin 6 expression in cancer tissues from Enz-treated patients compared to Enz naïve patients. Overall, syntaxin 6 plays an important role in the secretion of exosomes and increased survival of Enz-resistant PCa cells.