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The advent of more effective treatment combinations for metastatic hormone-sensitive prostate cancer (mHSPC) has been built on successes in therapy development for metastatic, castration-resistant prostate cancer (mCRPC). Both disease phases hold similar challenges and questions. Is there an optimal therapy sequence to maximize disease control and balance treatment burden? Are there clinical and biologically based subgroups that inform personalized and/or adaptive strategies? How can clinicians interpret data from clinical trials in the context of rapidly evolving technologies? Herein, we review the contemporary landscape of treatment for mHSPC, including disease subgroups informing both intensification and potential deintensification strategies. Furthermore, we provide current insights into the complex biology of mHSPC and discuss the potential clinical application of biomarkers to guide therapy selection and the development of novel personalized approaches.

Representative images of cell death staining in 22Rv1 empty vector control and p65 overexpressing tumoroids treated +/- DMAPT and/or enzalutamide.

List of qPCR primers.

NF-κB activation has been linked to prostate cancer progression and is commonly observed in castrate-resistant disease. It has been suggested that NF-κB–driven resistance to androgen-deprivation therapy (ADT) in prostate cancer cells may be mediated by aberrant androgen receptor (AR) activation and AR splice variant production. Preventing resistance to ADT may therefore be achieved by using NF-κB inhibitors. However, low oral bioavailability and high toxicity of NF-κB inhibitors is a major challenge for clinical translation. Dimethylaminoparthenolide (DMAPT) is an oral NF-κB inhibitor in clinical development and has already shown favorable pharmacokinetic and pharmacodyanamic data in patients with heme malignancies, including decrease of NF-κB in circulating leuchemic blasts. Here, we report that activation of NF-κB/p65 by castration in mouse and human prostate cancer models resulted in a significant increase in AR variant-7 (AR-V7) expression and modest upregulation of AR. In vivo castration of VCaP-CR tumors resulted in significant upregulation of phosphorylated-p65 and AR-V7, which was attenuated by combination with DMAPT and DMAPT increased the efficacy of AR inhibition. We further demonstrate that the effects of DMAPT-sensitizing prostate cancer cells to castration were dependent on the ability of DMAPT to inhibit phosphorylated-p65 function.Implications:Our study shows that DMAPT, an oral NF-κB inhibitor in clinical development, inhibits phosphorylated-p65 upregulation of AR-V7 and delays prostate cancer castration resistance. This provides rationale for the development of DMAPT as a novel therapeutic strategy to increase durable response in patients receiving AR-targeted therapy.

Objectives To estimate the lifetime health and economic outcomes of selecting active surveillance (AS), radical prostatectomy (RP), or radiation therapy (RT) as initial management for low- or favorable-risk localized prostate cancer. Methods A discrete-event simulation model was developed using evidence from published randomized trials. Health outcomes were measured in life-years and quality-adjusted life-years (QALYs). Costs were included from a public payer perspective in Australian dollars. Outcomes were discounted at 5% over a lifetime horizon. Probabilistic and scenario analyses quantified parameter and structural uncertainty. Results A total of 60% of patients in the AS arm eventually received radical treatment (surgery or radiotherapy) compared with 90% for RP and 91% for RT. Although AS resulted in fewer treatment-related complications, it led to increased clinical progression (AS 40.7%, RP 17.6%, RT 19.9%) and metastatic disease (AS 13.4%, RP 6.1%, RT 7.0%). QALYs were 10.88 for AS, 11.10 for RP, and 11.13 for RT. Total costs were A$17 912 for AS, A$15 609 for RP, and A$15 118 for RT. At a willingness to pay of A$20 000/QALY, RT had a 61.4% chance of being cost-effective compared to 38.5% for RP and 0.1% for AS. Conclusions Although AS resulted in fewer and delayed treatment-related complications, it was not found to be a cost-effective strategy for favorable-risk localized prostate cancer over a lifetime horizon because of an increase in the number of patients developing metastatic disease. RT was the dominant strategy yielding higher QALYs at lower cost although differences compared with RP were small.

It remains unclear which patients with metastatic germ cell tumours (mGCTs) need prophylactic anticoagulation to prevent venous thromboembolic events (VTEs).To assess the risk and onset of VTEs stratified by risk factors.This multi-institutional retrospective dataset included mGCT patients treated with first-line platinum-based chemotherapy.Patients with prophylactic anticoagulation were excluded.A regression analysis was performed to select risk factors for VTEs. The simulated number needed to treat (NNT) and the number needed to harm (NNH) with prophylactic anticoagulation were calculated based on the cumulative incidences retrieved from this study and hazard rates of recently published trials describing the efficacy of prophylactic anticoagulation to prevent VTEs and the risk of bleeding events.From 1120 patients, 121 (11%) had a VTE, which occurred prior to chemotherapy in 49 (4%) and on or after chemotherapy in 72 (6%). Six patients (1%) had a bleeding event without anticoagulation. After backward regression, the one risk factor for a VTE during or after chemotherapy was the use of a venous access device. The simulated cumulative VTE incidence from prophylactic anticoagulation for patients on or after chemotherapy would translate into an NNT of 45 (95% confidence interval [CI] 36-56) and an NNH of 186 (95% CI 87-506). Limitations are mainly related to the retrospective nature of the study.The mGCTs associated VTEs are most common before and during, but not after, chemotherapy. Avoiding venous access device and/or prophylactic anticoagulation with an acceptable risk-benefit profile may decrease VTE occurring on chemotherapy.We found that venous thromboembolic events (VTEs) occur rarely after chemotherapy. Based on experience of prophylactic anticoagulation in other cancers, we conclude that the risk of VTE in men undergoing chemotherapy for metastatic germ cell tumours can be decreased by thromboprophylaxis with a reasonable risk-benefit profile and by avoidance of venous access devices.

Phenotypic plasticity is a hallmark of cancer and increasingly realized as a mechanism of resistance in androgen indifferent prostate tumors. It is critical to identify mechanisms and actionable targets driving phenotypic plasticity. Here, we report that loss of tristetraprolin (TTP, geneZFP36), an RNA binding protein that regulates mRNA stability increases NF-κB activation and is associated with higher rates of aggressive disease and early recurrence in primary prostate cancer (PCa). We examined the clinical and biological impact ofZFP36loss combined withPTENloss, a known driver of PCa. Combined loss ofPTENandZFP36expression was associated with increased risk of recurrence in multiple independent primary PCa cohorts, and significantly reduced overall survival and time to progression following castration in genetically engineered mouse models.ZFP36loss alters the cell state that is driven byPTENloss, demonstrated by positive enrichment of gene sets including EMT, inflammation, TNFα/NF-κB, IL6-JAK/STAT3.ZFP36loss also induces enrichment of multiple gene sets involved in cell migration, chemotaxis, and proliferation. Use of the NF-κB inhibitor dimethylaminoparthenolide induced significant therapeutic responses in tumors withPTENandZFP36co-loss and reversed castration resistance. This work identifies a novel molecular mechanism driving phenotypic plasticity and castration resistance through loss ofZFP36expression, that can be reversed by inhibition of NF-κB activity.

Prostate cancers are considered to be immunologically ‘cold’ tumors given the very few patients who respond to checkpoint inhibitor (CPI) therapy. Recently, enrichment of interferon-stimulated genes (ISGs) predicted a favorable response to CPI across various disease sites. The enhancer of zeste homolog-2 (EZH2) is overexpressed in prostate cancer and known to negatively regulate ISGs. In the present study, we demonstrate that EZH2 inhibition in prostate cancer models activates a double-stranded RNA–STING–ISG stress response upregulating genes involved in antigen presentation, Th1 chemokine signaling and interferon response, including programmed cell death protein 1 (PD-L1) that is dependent on STING activation. EZH2 inhibition substantially increased intratumoral trafficking of activated CD8(+) T cells and increased M1 tumor-associated macrophages, overall reversing resistance to PD-1 CPI. Our study identifies EZH2 as a potent inhibitor of antitumor immunity and responsiveness to CPI. These data suggest EZH2 inhibition as a therapeutic direction to enhance prostate cancer response to PD-1 CPI.

The immunosuppressive cytokine interleukin- 8 (IL-8), produced by tumor cells and some myeloid cells, promotes inflammation, angiogenesis, and metastasis. In our discovery work, elevated serum IL-8 at androgen deprivation therapy (ADT) initiation portended worse overall survival (OS). Leveraging serum samples from the phase 3 CHAARTED trial of patients treated with ADT +/- docetaxel for metastatic hormone-sensitive prostate cancer (mHSPC), we validated these findings.Two hundred and thirty-three patients had serum samples drawn within 28 days of ADT initiation. The samples were assayed using the same Mesoscale Multiplex ELISA platform employed in the discovery cohort. After adjusting for performance status, disease volume, and de novo/metachronous metastases, multivariable Cox proportional hazards models assessed associations between IL-8 as continuous and binary variables on OS and time to castration-resistant prostate cancer (CRPC). The median IL-8 level (9.3 pg/ml) was the a priori binary cutpoint. Fixed-effects meta-analyses of the discovery and validation sets were performed.Higher IL-8 levels were prognostic for shorter OS (continuous: hazard ratio [HR] 2.2, 95% confidence interval [CI]: 1.4-3.6, p = .001; binary9.3: HR 1.7, 95% CI: 1.2-2.4, p = .007) and time to CRPC (continuous: HR 2.3, 95% CI: 1.6-3.3, p .001; binary: HR 1.8, 95% CI: 1.3-2.5, p .001) and independent of docetaxel use, disease burden, and time of metastases. Meta-analysis including the discovery cohort, also showed that binary IL-8 levels9.3 pg/ml from patients treated with ADT alone was prognostic for poorer OS (HR 1.8, 95% CI: 1.2-2.7, p = .007) and shorter time to CRPC (HR 1.4, 95% CI: 0.99-1.9, p = .057).In the phase 3 CHAARTED study of men with mHSPC at ADT initiation, elevated IL-8 portended worse survival and shorter time to castration-resistant prostate cancer independent of docetaxel administration, metastatic burden, and metachronous versus de novo metastatic presentation. These findings support targeting IL-8 as a strategy to improve mHSPC outcomes.

Fixed-tissue ChIP-seq for H3K27 acetylation (H3K27ac) profiling (FiTAc-seq) is an epigenetic method for profiling active enhancers and promoters in formalin-fixed, paraffin-embedded (FFPE) tissues. We previously developed a modified ChIP-seq protocol (FiT-seq) for chromatin profiling in FFPE. FiT-seq produces high-quality chromatin profiles particularly for methylated histone marks but is not optimized for H3K27ac profiling. FiTAc-seq is a modified protocol that replaces the proteinase K digestion applied in FiT-seq with extended heating at 65 °C in a higher concentration of detergent and a minimized sonication step, to produce robust genome-wide H3K27ac maps from clinical samples. FiTAc-seq generates high-quality enhancer landscapes and super-enhancer (SE) annotation in numerous archived FFPE samples from distinct tumor types. This approach will be of great interest for both basic and clinical researchers. The entire protocol from FFPE blocks to sequence-ready library can be accomplished within 4 d. This protocol describes a ChIP-seq procedure optimized for profiling H3K27 acetylation in archived formalin-fixed, paraffin-embedded (FFPE) tissues sampled through whole or macrodissected sectioning or from punched cores.

The successful development of effective cancer immunotherapy, in particular immune checkpoint inhibitors, has changed the treatment paradigm of many tumor types. In light of the limited efficacy of checkpoint inhibitors demonstrated in recent clinical trials in refractory prostate cancer, this review highlights important recent and ongoing studies that are shaping the pursuit of effective immunotherapy for prostate cancer.We review two overarching themes with respect to recent studies of prostate cancer immunotherapy: evolving therapeutic strategies and novel biological findings, including the landscape of predictive biomarkers of immunotherapy response.Novel and combinatorial immunotherapy strategies are being implemented across the clinical spectrum of prostate cancer. Greater understanding of complex tumor-immune interactions and the determinants of therapy response in prostate cancer is an area of intense investigation, and will inform both translational and clinical immuno-oncology research in the field.

Background Metastatic germ cell tumor (mGCT) patients receiving chemotherapy have increased risk of life‐threatening venous thromboembolism (VTE). Identifying VTE risk factors may guide thromboprophylaxis in this highly curable population. Methods Data were collected from mGCT patients receiving first‐line platinum‐based chemotherapy at 22 centers. Predefined variables included International Germ Cell Cancer Collaborative Group (IGCCCG) risk classification, long‐axis diameter of largest retroperitoneal lymph node (RPLN), Khorana score, and use of indwelling vascular access device (VAD). VTE occurring at baseline, during chemotherapy and within 90 days, was analyzed. Results Data from 1135 patients were collected. Median age was 31 years (range 10‐74). IGCCCG risk was 64% good, 20% intermediate, and 16% poor. VTE occurred in 150 (13%) patients. RPLN >3.5 cm demonstrated highest discriminatory accuracy for VTE (AUC 0.632, P, Venous thromboembolism can cause morbidity in germ cell tumor patients receiving chemotherapy; large retroperitoneal lymphadenopathy (RPLN) and indwelling vascular access devices (VAD) are significant VTE risk factors. VAD insertion should be avoided and thromboprophylaxis can be considered for large RPLN.

BACKGROUND: Inflammation and one of its mediators, NF-kappa B (NFκB), have been implicated in prostate cancer carcinogenesis. We assessed whether germline polymorphisms associated with NFκB are associated with the risk of developing lethal disease (metastases or death from prostate cancer).METHODS: Using a Bayesian approach leveraging NFκB biology with integration of publicly available datasets we used a previously defined genome-wide functional association network specific to NFκB and lethal prostate cancer. A dense-module-searching method identified modules enriched with significant genes from a genome-wide association study (GWAS) study in a discovery data set, Physicians' Health Study and Health Professionals Follow-up Study (PHS/HPFS). The top 48 candidate single nucleotide polymorphisms (SNPs) from the dense-module-searching method were then assessed in an independent prostate cancer cohort and the one SNP reproducibly associated with lethality was tested in a third cohort. Logistic regression models evaluated the association between each SNP and lethal prostate cancer. The candidate SNP was assessed for association with lethal prostate cancer in 6 of 28 studies in the prostate cancer association group to investigate cancer associated alterations in the genome (PRACTICAL) Consortium where there was some medical record review for death ascertainment which also had SNP data from the ONCOARRAY platform. All men self-identified as Caucasian.RESULTS: The rs1910301 SNP which was reproducibly associated with lethal disease was nominally associated with lethal disease (odds ratio [OR] = 1.40; p = .02) in the discovery cohort and the minor allele was also associated with lethal disease in two independent cohorts (OR = 1.35; p = .04 and OR = 1.35; p = .07). Fixed effects meta-analysis of all three cohorts found an association: OR = 1.37 (95% confidence interval [CI]: 1.15-1.62, p = .0003). This SNP is in the promoter region of FRAS1, a gene involved in epidermal-basement membrane adhesion and is present at a higher frequency in men with African ancestry. No association was found in the subset of studies from the PRACTICAL consortium studies which had a total of 106 deaths out total of 3263 patients and a median follow-up of 4.4 years.CONCLUSIONS: Through its connection with the NFκB pathway, a candidate SNP with a higher frequency in men of African ancestry without cancer was found to be associated with lethal prostate cancer across three well-annotated independent cohorts of Caucasian men.

Background The phase III CHAARTED trial established upfront androgen-deprivation therapy (ADT) plus docetaxel (D) as a standard for metastatic hormone-sensitive prostate cancer (mHSPC) based on meaningful improvement in overall survival (OS). Biological prognostic markers of outcomes and predictors of chemotherapy benefit are undefined. Patients and methods Whole transcriptomic profiling was performed on primary PC tissue obtained from patients enrolled in CHAARTED prior to systemic therapy. We adopted an a priori analytical plan to test defined RNA signatures and their associations with HSPC clinical phenotypes and outcomes. Multivariable analyses (MVAs) were adjusted for age, Eastern Cooperative Oncology Group status, de novo metastasis presentation, volume of disease, and treatment arm. The primary endpoint was OS; the secondary endpoint was time to castration-resistant PC. Results The analytic cohort of 160 patients demonstrated marked differences in transcriptional profile compared with localized PC, with a predominance of luminal B (50%) and basal (48%) subtypes, lower androgen receptor activity (AR-A), and high Decipher risk disease. Luminal B subtype was associated with poorer prognosis on ADT alone but benefited significantly from ADT + D [OS: hazard ratio (HR) 0.45; P = 0.007], in contrast to basal subtype which showed no OS benefit (HR 0.85; P = 0.58), even in those with high-volume disease. Higher Decipher risk and lower AR-A were significantly associated with poorer OS in MVA. In addition, higher Decipher risk showed greater improvements in OS with ADT + D (HR 0.41; P = 0.015). Conclusion This study demonstrates the utility of transcriptomic subtyping to guide prognostication in mHSPC and potential selection of patients for chemohormonal therapy, and provides proof of concept for the possibility of biomarker-guided selection of established combination therapies in mHSPC.

Increasing awareness among Muslims with respect to the Halal status of food has intensified efficient and effective food-source authentications that are science-basedprotocol. Traceability of gelatine to its source remains a daunting scientific task prior to classification of gelatine Halal status. The methodology of this study involves UV-Vis spectroscopic measurement of the degree of browning during Maillard reaction of different gelatine sources with the different type of reducing sugar. D-(+)-xylose has the highest value of browning value (A420nm) of Maillard reaction with gelatine among compared to another type of reducing sugar used. Principle Component Analysis (PCA) used to differentiate the sources of gelatine and successfully identify the major contribution of D-(+)-xylose in the browning value. The score plots of the first principle component (PC1) and the second component (PC2) could be classified and differentiated of gelatine types (porcine, bovine and fish) using variables of browning value of Maillard reaction of gelatinees with different types of sugar, as evaluated using spectrophotometer at 420 nm.

Background TP53, PTEN, and RB1 tumor suppressor genes (TSGs) are recurrently altered in treatment-resistant prostate cancer. Cooperative loss of two or more TSGs may drive more aggressive disease. Objective To determine clinical outcomes of single and compound TSG alterations across the spectrum of prostate cancer. Design, setting, and participants Massively parallel targeted sequencing using castration-sensitive prostate cancer (CSPC; localized [L] and metastatic [M1]) and castration-resistant prostate cancer (CRPC) specimens (n = 285). TSG altered (TSG-alt) was any copy number loss or deleterious mutation of one or more TSGs (TP53, PTEN, and RB1). Outcome measurements and statistical analysis For L-CSPC, event-free survival (EFS) and time to CRPC were estimated. For M1-CSPC and M1-CRPC, overall survival (OS) was estimated. Cox regression models assessed the association between cumulative TSG hits (zero hits vs one hit vs two to three hits) and outcomes with multivariable analyses adjusted for clinicopathological factors. Results and limitations TSG variants increased with advanced disease (L-CSPC: 39%; M1-CSPC: 63%, M1-CRPC: 92%). TSG-alt L-CSPC had shorter EFS (median 2.6 yr, hazard ratio [HR] 1.95, 95% confidence interval [CI] 1.22–3.13) and time to CRPC (median 9.5 mo, HR 3.36, 95% CI 1.01–11.16). Cumulative gene hits led to an incremental risk of relapse (EFS: one gene, HR 1.69, 95% CI 0.99–2.87; two to three genes, HR 2.70, 95% CI 1.43–5.08; both versus zero genes, p = 0.004). There was evidence of inferior OS with increasing TSG hits in the metastatic cohorts. Only four (8%) patients in the M1-CRPC cohort were TSG-neg, one of whom died after 5.2 yr. Multivariable analyses adjusting for mutational and copy number burden did not demonstrate a significant independent association of increasing gene hits and poorer outcomes. Conclusions Deleterious TSG variants are associated with an increased risk of relapse (L) and death (M1) in CSPC. Poorer outcomes are seen with compound gene hits in both early and advanced disease, and this may in part reflect increasing global genomic instability. Patient summary Men with prostate tumors with compound tumor suppressor gene mutations have poorer outcomes. These findings help identify patients with aggressive features who may benefit from intensified treatment.

BACKGROUND: In 2004, docetaxel was shown to prolong the overall survival (OS) of patients with metastatic castration-resistance prostate cancer (mCRPC). Since 2010, five new systemic therapies have been shown to prolong OS in men with mCRPC. We sought to evaluate the aggregate impact of these newer therapies on the OS of patients with mCRPC. METHODS: Two cohorts of patients diagnosed with mCRPC between 2004–2007, treated with drugs used in the limited treatment era only (A), and between 2010–2013, treated also with newer therapies (B), were identified from the Dana-Farber Cancer Institute database. The analysis endpoint was OS within 5 years after mCRPC diagnosis. Kaplan-Meier method assessed time-to-event distributions with median (95% confidence interval [CI]). A piece-wise regression model assessed the association between endpoint and treatment cohorts with estimate of hazard ratio (HR) with 95% CI within two time segments in univariate and multivariable analyses adjusting for relevant covariates. RESULTS: Compared to cohort A (n=318), cohort B (n=272) patients in newer therapy era demonstrated an OS advantage (2.8 v 2.2 years) with a 41% decreased risk of death (HR = 0.59; 95% CI, 0.47–0.74; P < .0001), and a 3-year OS rate of 46% v 33%. This benefit was accentuated (median OS 2.7 v 2.1 years; HR = 0.46; 95% CI, 0.32–0.67; P < .0001) in patients who initially presented with de-novo metastatic disease (de-novo). On multivariable analysis, longer OS was associated with cohort B v A and performance status 0 v 1. CONCLUSIONS: Using a single-institution registry, mCRPC patients treated since 2010 had a significant survival improvement versus those treated before 2010. Although the median survival was only modestly improved and less than predicted when simply adding each newer drug survival advantage, the cumulative benefit from the new therapies was more pronounced in longer term survivors and de-novo patients.

The appropriate management of localized or metastatic hormone-sensitive prostate cancer (HSPC) patients harboring tumor BRCA mutations (tBRCAm) is not well-characterized. We sought to evaluate the prevalence and clinical outcomes of patients with tBRCAm and localized or de novo metastatic HSPC. We performed a multicenter, international, retrospective cohort study of localized (cohort 1) and de novo metastatic (cohort 2) HSPC patients who underwent tumor BRCA1 and BRCA2 sequencing from 2013 to 2019. Primary endpoints included event-free survival (EFS) and metastases-free survival (MFS) for cohort 1, and time to castration-resistant prostate cancer (TTCRPC) and overall survival (OS) for cohort 2. Kaplan–Meier method and Cox regression models estimated the association of endpoints with tBRCA status. Of 399 identified patients with localized and de novo metastatic HSPC who underwent tumor BRCA1 and BRCA2 sequencing, 3.1% (8/258) patients of cohort 1 and 10.6% (15/141) patients of cohort 2 harbored tBRCAm. The median follow-up was 33 and 36 months, respectively. In cohort 1, median EFS was 18.1 vs. 57 months (p = 0.28) and MFS was 37 vs. 153.4 months (p = 0.08) for patients with tBRCAm compared to patients with no tBRCAm. In cohort 2, the TTCRPC was 24 vs. 19 months (p = 0.65) and OS was 64 vs. 60 months (p = 0.95) in patients with and without tBRCAm, respectively. While tBRCAm seems to be associated with greater relapse risk in localized disease, tBRCAm did not influence the clinical outcomes of patients presenting with de novo metastatic HSPC treated with conventional therapies. tBRCAm may exert different prognostic effects across the clinical spectrum of prostate cancer.

PURPOSE Clinical stage I (CSI) nonseminoma (NS) is a disease limited to the testis without metastases. One treatment strategy after orchiectomy is adjuvant chemotherapy. Little is known about the outcome of patients who experience relapse after such treatment. PATIENTS AND METHODS Data from 51 patients with CSI NS who experienced a relapse after adjuvant bleomycin, etoposide, and cisplatin (BEP) from 18 centers/11 countries were collected and retrospectively analyzed. Primary outcomes were overall and progression-free survivals calculated from day 1 of treatment at first relapse. Secondary outcomes were time to, stage at, and treatment of relapse and rate of subsequent relapses. RESULTS Median time to relapse was 13 months, with the earliest relapse 2 months after start of adjuvant treatment and the latest after 25 years. With a median follow-up of 96 months, the 5-year PFS was 67% (95% CI, 54% to 82%) and the 5-year OS was 81% (95% CI, 70% to 94%). Overall, 19 (37%) of 51 relapses occurred later than 2 years. Late relapses were associated with a significantly higher risk of death from NS (hazard ratio, 1.10 per year; P = .01). Treatment upon relapse was diverse: the majority of patients received a combination of chemotherapy and surgery. Twenty-nine percent of patients experienced a subsequent relapse. At last follow-up, 41 patients (80%) were alive and disease-free, eight (16%) had died of progressive disease, and one patient (2%) each had died from therapy-related or other causes. CONCLUSION Outcomes of patients with relapse after adjuvant BEP seem better compared with patients who experience relapse after treatment of metastatic disease but worse compared with those who have de-novo metastatic disease. We found a substantial rate of late and subsequent relapses. There seem to be three patterns of relapse with different outcomes: pure teratoma, early viable NS relapse (< 2 years), and late viable NS relapse (> 2 years).

Background: There is limited experience regarding the safety and efficacy of checkpoint inhibitors (CPI) in patients with autoimmune disorders (AD) and advanced urological cancers as they are generally excluded from clinical trials due to risk of exacerbations. Methods: This multicenter retrospective cohort analysis of patients with advanced renal cell cancer (RCC) and urothelial cancer (UC) with pre-existing AD treated with CPI catalogued the incidence of AD exacerbations, new immune-related adverse events (irAEs) and clinical outcomes. Competing risk models estimated cumulative incidences of exacerbations and new irAEs at 3 and 6 months. Results: Of 106 patients with AD (58 RCC, 48 UC) from 10 centers, 35 (33%) had grade 1/2 clinically active AD of whom 10 (9%) required corticosteroids or immunomodulators at baseline. Exacerbations of pre-existing AD occurred in 38 (36%) patients with 17 (45%) requiring corticosteroids and 6 (16%) discontinuing CPI. New onset irAEs occurred in 40 (38%) patients with 22 (55%) requiring corticosteroids and 8 (20%) discontinuing CPI. Grade 3/4 events occurred in 6 (16%) of exacerbations and 13 (33%) of new irAEs. No treatment-related deaths occurred. Median follow-up was 15 months. For RCC, objective response rate (ORR) was 31% (95% CI 20% to 45%), median time to treatment failure (TTF) was 7 months (95% CI 4 to 10) and 12-month overall survival (OS) was 78% (95% CI 63% to 87%). For UC, ORR was 40% (95% CI 26% to 55%), median TTF was 5.0 months (95% CI 2.3 to 9.0) and 12-month OS was 63% (95% CI 47% to 76%). Conclusions: Patients with RCC and UC with well-controlled AD can benefit from CPI with manageable toxicities that are consistent with what is expected of a non-AD population. Prospective study is warranted to comprehensively evaluate the benefits and safety of CPI in patients with AD., SCOPUS: ar.j, info:eu-repo/semantics/published

BACKGROUND Docetaxel is an effective therapy for metastatic castration-resistant prostate cancer (mCRPC); however, many patients experience febrile neutropenia (FN) and cease treatment early due to toxicity. It is not known whether lower dose (LD) q3-weekly docetaxel impacts toxicity or efficacy. METHODS Multicenter retrospective study included 166 patients with mCRPC who received q3-weekly docetaxel between 2010 and 2015. Demographic, disease, chemotherapy (standard dose, SD > 60 mg/m2 vs LD ≤ 60 mg/m2 ) and toxicity data were collected. Univariable and multivariable logistic and competing risk regression models evaluated docetaxel-dose association with FN and early treatment cessation (ETC) due to toxicity. Associations between dose and efficacy end points were also evaluated. Analyses were repeated employing inverse propensity score weights. RESULTS Patients who received LD docetaxel (28.9%) were older with poorer Eastern Cooperative Oncology Group (ECOG) status. Fifteen percent of patients experienced FN, with a nonsignificant trend to lower incidence in the LD group (multiple adjusted odds ratio [OR] = 0.42; P = 0.21). Neither baseline patient nor prior treatment factors were predictive of FN. ETC due to toxicity occurred in 35%, with risk associated with increasing age, comorbidity count and poorer ECOG. There was no difference between LD and SD with respect to ETC due to toxicity, in unweighted and weighted analyses (LD vs SD, multivariable weighted hazard ratio [HR] = 1.47; P = 0.08). LD was associated with reduced prostate-specific antigen (PSA) response (50% vs 66.1%, multivariable weighted HR = 0.54; P = 0.03) and overall survival (median 7.9 vs 13.8 months, multivariable weighted HR = 2.19; P

Fixed-tissue ChIP-seq for H3K27 acetylation (H3K27ac) profiling (FiTAc-seq) is an epigenetic method for profiling active enhancers and promoters in formalin-fixed, paraffin-embedded (FFPE) tissues. We previously developed a modified ChIP-seq protocol (FiT-seq) for chromatin profiling in FFPE. FiT-seq produces high-quality chromatin profiles particularly for methylated histone marks but is not optimized for H3K27ac profiling. FiTAc-seq is a modified protocol that replaces the proteinase K digestion applied in FiT-seq with extended heating at 65 °C in a higher concentration of detergent and a minimized sonication step, to produce robust genome-wide H3K27ac maps from clinical samples. FiTAc-seq generates high-quality enhancer landscapes and super-enhancer (SE) annotation in numerous archived FFPE samples from distinct tumor types. This approach will be of great interest for both basic and clinical researchers. The entire protocol from FFPE blocks to sequence-ready library can be accomplished within 4 d.

Prostate cancers are considered immunologically ‘cold’ tumors given the very few patients who respond to checkpoint inhibitor therapy (CPI). Recently, enrichment of interferon (IFN) response genes predicts a favorable response to CPI across various disease sites. The enhancer of zeste homolog-2 (EZH2) is over-expressed in prostate cancer and is known to negatively regulate IFN response genes. Here, we demonstrate that inhibition of EZH2 catalytic activity in prostate cancer models derepresses expression of double-strand RNA (dsRNA), associated with upregulation of genes involved in antigen presentation, Th-1 chemokine signaling, and interferon (IFN) response, including PD-L1. Similarly, application of a novel EZH2 derived gene signature to human prostate sample analysis indicated an inverse correlation between tumor EZH2 activity/expression with T-cell inflamed and IFN gene signatures and PD-L1 expression. EZH2 inhibition combined with PD-1 CPI significantly enhances antitumor response that is dependent on up-regulation of tumor PD-L1 expression. Further, combination therapy significantly increases intratumoral trafficking of activated CD8+ T-cells and M1 tumor associated macrophages (TAMs) with concurrent loss of M2 TAMs. Our study identifies EZH2 as a potent inhibitor of antitumor immunity and responsiveness to CPI. This data suggests EZH2 inhibition as a novel therapeutic direction to enhance prostate cancer response to PD-1 CPI.

Objective Prostate cancer is one of the most common male cancers in the world and accounts for substantial morbidity, mortality, loss of disability-adjusted life-years, and financial burden to patients and to the community. Metastatic prostate cancer has been managed for over 70 years with androgen deprivation therapy, but further life-prolonging therapies were not available until 2004. Since then, drugs such as docetaxel, abiraterone, enzalutamide, cabazitaxel, radium-223 dichloride, and (not available in Australia) sipuleucel-T have all demonstrated efficacy in prolongation of survival in castrate-resistant prostate cancer, and improvement in cancer-related morbidity. Data sources Peer-reviewed scientific publications, Australian Government agency reports, and expert opinion. Conclusion More recently, several of these agents have been given earlier in the treatment course to the hormone-sensitive metastatic setting, with even greater benefits in survival. These treatments have come at a cost: a literal financial cost to the community, and often to the patients and their families; and financial costs to the community to supply the drugs to those who need them. They also carry non-financial costs, including side effects of treatment, exacerbation of other co-morbidities, metabolic and bone health challenges, and psychological and social stresses, including those associated with longer survival with metastatic cancer. Implications for Nursing Practice The role of the nurse in management of these issues has never been more important. Nurses are often uniquely placed to educate men with prostate cancer and their families, screen for and identify adverse effects of treatment, and provide education and support not otherwise available. Nurses are central to the streamline of care coordination within the multidisciplinary team and the holistic care journey for men and their partners through the health care system. This review discusses several of these aspects to inform practice.

44 Background: Somatic BRCA gene mutations ( sBRCAm) have been identified in a significant proportion of patients (pts) with castration resistant PC (CRPC), with mixed data regarding effect on CRPC therapies. However, the prevalence and clinical significance in mHSPC are not well characterized. Methods: Sequencing of primary tumor for sBRCA1/2 was performed in unselected pts with de novo mHSPC. We assessed the association of sBRCAm on time to CRPC (TTCRPC) and overall survival (OS) from diagnosis using Kaplan-Meier method, as well as PSA response (50% fall from baseline). Associations were evaluated using a Cox regression model with multivariable analyses adjusting for docetaxel use. Results: We identified 69 pts with de novo mHSPC, of whom 7 (10%) harbored a pathogenic sBRCA2m. Median age at diagnosis was 66 years. The majority were classified as high volume disease (n=54; 84%) with Gleason 9-10 grade (n=40; 61%). Therapies in the HSPC setting included ADT alone (n=29, 42%), ADT + Docetaxel (n=35, 51%), and ADT + Docetaxel + Abiraterone (n=5, 7%). Only 1 s BRCA2m case compared to 39 wild-type pts were treated with docetaxel. PSA response was achieved in 65 (96%) and PSA £ 0.2 ng/ml at 7 mos in 20 (31%) pts, without significant association with BRCA status ( p=0.13 and p=0.66, respectively). At a median FU of 29 mos, CRPC occurred in 44 (64%) pts with a median TTCRPC of 24 mos. TTCRP was numerically shorter for non-mutated pts compared to sBRCAm (22 vs. 40 mos, HR 0.5, p=0.23); there was no significant association with docetaxel use. In multivariate analyses, there was no significant association between sBRCAm and TTCRPC (HR 0.43, p=0.175). Median OS was 74 mos without any difference according to BRCA status ( p=0.30) nor docetaxel use ( p=0.14). Conclusions: In this real-world study of routine s BRCA1/2 assessment, we found a 10% prevalence in de novo mHSPC. Time to CRPC trended longer in the sBRCAm population despite less use of docetaxel, indicating that pts with sBRCAm appear to have at least similar outcomes with standard mHSPC therapies. Larger datasets correlating genomics with outcomes in this subset of pts are warranted.

162 Background: Through gene expression profiling (GEP), the PAM50 classifier demonstrates prognostic value in localized prostate cancer (PCa). Pre-clinical drug response models predict increased taxane sensitivity in luminal subtypes compared to basal subtype. Men with mHSPC and high-risk features have greatest benefit from androgen deprivation therapy (ADT) plus docetaxel (D) vs ADT alone. We therefore sought to test the prognostic and predictive value of PAM50 in pre-ADT specimens from E3805 CHAARTED. Methods: Whole transcriptomic profiling of formalin-fixed, paraffin-embedded primary PCa biopsies from pts enrolled in the E3805 CHAARTED trial of ADT vs ADT+D was performed using the Human Exon 1.0 ST microarray platform (Decipher Biosciences). Normalized gene expression was used to classify subjects as luminal A, luminal B or basal subtype. Multivariable analyses (MVA) adjusted for ECOG status, de novo metastasis vs prior local therapy and volume of disease. The primary endpoint was overall survival (OS). Secondary endpoint was time to castration resistant PCa (TTCRPC). Results: Successful GEP was completed in 160 of 198 pts with available specimens. Eighty (50%), 77 (48%) and 3 (2%) pts were classified as luminal B, basal and luminal A, respectively. High volume disease was similarly present in luminal B (79%) and basal (78%) subtypes. In the ADT arm, luminal B subtype was associated with shorter OS vs basal (HR 1.75, p=0.05); consistent in MVA. Pts with luminal B subtype treated with ADT+D showed significant improvement in TTCRPC and OS (Table). By contrast, basal subtype showed no OS benefit from ADT+D even in pts with high volume disease. Conclusions: We demonstrate that GEP identifies tumor subtypes associated with differential benefit from chemohormonal therapy for mHSPC. Luminal B subtype is associated with poorer OS with ADT alone and benefits from addition of D. Basal subtype shows a lack of OS benefit from upfront ADT+D. We plan to validate these findings in independent trial cohorts.[Table: see text]

402 Background: Recent trials randomising patients (pts) receiving systemic cancer therapy showed that prophylactic anticoagulation (PAK) halves the risk of venous thromboembolic events (VTE) and doubles the risk of bleeding (Khorana et al. & Carrier et al., both NEJM 2019). In pts with metastatic germ cell tumors (mGCT) VTE is a frequent complication but it remains unclear whether PAK should be recommended because the number of mGCT pts in those trials was small. We aimed to determine the risk of VTE before, during and after chemotherapy and in mGCT pts without and with risk factors for VTE (retroperitoneal lymph nodes, Khorana score, venous access device) and to calculate the number needed to treat (NNT) and number needed to harm (NNH) of PAK. Methods: This retrospective analysis included mGCT pts treated with first-line platinum-based chemotherapy. We excluded patients who received PAK, with a known history of coagulopathy or VTE and extracted data about VTE and bleeding events. Cumulative VTE incidence was calculate for patients without and with increasing number of known risk factors for VTEs. NNT and NNH were calculated by assuming similar hazard ratios (HR) to reduce VTEs and increase bleeding as previously published (HR 0.66 and 1.96, Khorana et al., NEJM 2019). Results: Out of 1039 pts, 132 (13%) presented with VTE, 6 (1%) with bleeding. One patients died of VTE and 1 because of bleeding. Patients without any VTE risk factors experience VTE in 20/347 (5%) which translated into a NNT of 55 compared to the NNH of 84 respectively. Before start of chemotherapy 52 (5%) pts (NNT=60) presented with VTE of which 22 were reported symptomatic 21 asymptomatic/incidentally detected VTE on staging scans (9 unknowns). During chemotherapy 79 (8%) pts (NNT=40) were diagnosed with VTE whereas 19 (2%) pts (NNT=162) were diagnosed with VTE after chemotherapy. Conclusions: Our analysis revealed that even mGCT patients without risk factors for VTE show a relevant cumulative VTE incidence of 7%. Especially before and during but not after chemotherapy the benefits of PAK to prevent VTE outweighs the small increased risk of bleeding.

547 Background: Cisplatin-based NAC followed by surgery is the gold standard treatment of non-metastatic MIBC. However, predictive biomarkers have not been established yet. Here, we addressed the relevance of TILs for NAC response and prognosis in MIBC patients (pts). Methods: We conducted a single center, retrospective cohort analysis of consecutive MIBC pts treated with cisplatin-based NAC followed by surgery. Pts with pathological complete response (pCR; ypT0/isN0) were grouped as responders, pts with pathological residual disease as non responders. TIL stromal count were assessed pre- and post-NAC. Next Generation Sequencing of selected genes was performed on pre-NAC samples. We catalogued the 3-years(y) relapse free rate and 3-y overall survival rate (OS, Kaplan Meier) for the overall cohort and by subgroups. Results: Of the 25 pts who received cisplatin-gemcitabine NAC, a total of 14 (56%) pts achieved a pCR and 11 (44%) had residual disease. NAC was discontinued in 17 (65%) after completing treatment; and in 8 (32%) pts after 2 cycles due to toxicity. Median follow-up was 54.2 months(mos). At baseline, median TIL count was 60% in the overall cohort. Numerically higher TIL count was observed among responders (80%) compared to non-responders (50%) ( p=0.22). Median TIL count post-NAC in residual samples was 40%, not significantly different to matched pre-NAC samples ( p=0.93). Overall, 3-y relapse free rate was 74.7% (95%CI 51.7-87.9); 3-y OS rate was 79.6% (95%CI 57.6-91) with 6 deaths of which 4 were related to metastatic disease. Table reports subset analyses. Most frequently altered genes were PIK3CA and TP53 in the overall cohort (each 20%) and in the responders subgroup (each 29%). Conclusions: In our study, pts who achieved pCR had numerically greater TIL infiltrate in baseline samples and pCR was associated with reduced risk of recurrence. TILs did not increase in residual tumors after NAC. The independent predictive value of TILs warrants assessment in large cohorts.[Table: see text]

171 Background: IL-8 (CXCL-8) is a cytokine produced by leukocytes and tumor cells, which promotes inflammation, angiogenesis, anti-apoptosis, and metastasis. Our published training set identified serum IL-8 levels drawn within 28 days of androgen deprivation therapy (ADT) initiation as prognostic for shorter overall survival (OS). We sought to validate this finding using samples from CHAARTED patients treated with ADT +/- docetaxel for mHSPC. Methods: We assayed serum samples drawn ≤28 days from ADT initiation from 233 patients using the same Mesoscale multiplex ELISA assay as the training set. Multivariable Cox proportional hazards models adjusted for ECOG performance status, disease volume, and prior local therapy (radiation/prostatectomy vs. none) with IL-8 as continuous and binary variables. The training median 9.3 pg/mL was the a priori binary cutpoint. Fixed-effects meta-analysis of the training and validation sets was performed. Results: Higher IL-8 levels were prognostic for shorter OS and time to CRPC for ADT alone and ADT + docetaxel (Table) and were independent of disease volume or docetaxel use. Meta-analysis of binary IL-8 levels >9.3pg/mL from patients treated with ADT alone (training + validation cohorts) was prognostic for poorer OS (HR 1.8, 95% CI: 1.2-2.7, p= 0.007) and shorter time to CRPC (HR: 1.4, 95%CI: 0.99-1.9, p=0.057). The validation cohort’s baseline median IL-8 level was similar at 10 pg/mL. Conclusions: Higher IL-8 is prognostic for shorter time to CRPC and OS independent of docetaxel use, disease volume and presentation with metachronous or de novo metastatic disease. These findings support targeting IL-8 as a strategy to improve mHSPC outcomes.[Table: see text]

421 Background: Most metastatic GCTs are cured with cisplatin-based chemotherapy. Clinical factors of adverse GCT-specific survival have been identified, however patterns of death are not well-defined and would inform clinical care and biological investigation. Methods: This multi-institutional study pooled data of male pts with death related to GCT from high-volume adult GCT academic centers (Dana-Farber Cancer Institute, Memorial Sloan Kettering Cancer Center, Indiana University) over 20 years (1997-2017). Pts were annotated for site, stage, IGCCC risk, histology, primary therapy and relapse variables (including relapse histology, metastatic (met) burden, salvage and palliative therapies), and detailed cause of GCT death. Cox regression assessed associations with survival. Results: The pooled cohort of 620 pts comprised 90% non-seminoma, 21% mediastinal primary and at diagnosis, 59% were stage III, 64% poor risk; 48% received high-dose chemotherapy plus transplantation. Median survival (OS) from first relapse after metastasis was 12.0 mos. Leading causes of death were chemorefractory GCT (83.1%), secondary somatic malignancy (SSM) arising from teratoma (9.4%), acute toxicity (4.5%), late toxicity (2.3%) and progressive untransformed pure teratoma (0.8%). Late relapse (relapse >2 years after 1st-line therapy) occurred in 11.3% at a median of 5.9 yrs. Of these pts, 1/3 were stage I at initial diagnosis and 75% were good or intermediate risk at met diagnosis, and were more likely to have SSM histology/death vs early relapse. Late relapsing disease (HR 0.48, p

43 Background: PARP inhibitors (PARPi) and platinum chemotherapy cause synthetic lethality and result in clinical benefit in men with mCRPC whose tumors harbor deleterious alterations in DDR genes. BRCA2 is the strongest predictor, but data supports a role for BRCA1, ATM, and other genes. PARPi are more expensive than platinum chemotherapy; whether they are more effective is not known. We evaluated outcomes in men with DDR-deficient mCRPC treated with PARPi or platinum chemotherapy. Methods: We identified men treated at Dana-Farber Cancer Institute who received olaparib or carboplatin for mCRPC and underwent tumor mutation profiling. Progression-free survival (PFS) was determined using Prostate Cancer Working Group 3 guidelines. Pathogenic germline or somatic single-nucleotide variants, insertions/deletions, and copy number loss in BRCA2, BRCA1, and ATM, were identified. Log-rank test was utilized to compare differences in PFS. Results: We identified 27 men who received olaparib: 19/27 (70.4%) received prior taxane chemotherapy and 3/27 (11.1%) prior carboplatin; 16 had mono- or bi-allelic alterations in BRCA2 and 2 had alterations in BRCA1 or ATM. We identified 41 men treated with carboplatin: 39/41 (95.1%) received carboplatin in combination with a taxane; 36/41 (87.8%) received prior taxane chemotherapy and 7/41 (17.1%) prior PARPi; 16 had BRCA2 alterations and 5 had alterations in BRCA1 or ATM. Among men with BRCA2 alterations, there was no significant difference in PFS (HR 0.71, 95% CI 0.45-1.11; p = 0.13) between those treated with olaparib (4.9 months [m]) versus carboplatin (5.4 m). Similarly, no difference in PFS (HR 0.80, 95% CI 0.54-1.16; p = 0.24) was observed among men with BRCA2, BRCA1, or ATM alterations treated with olaparib (3.8 m) versus carboplatin (3.6 m). Conclusions: In a small real-world cohort of men with mCRPC harboring deleterious alterations in BRCA2, BRCA1, and ATM, there was no difference in PFS between those treated with olaparib versus carboplatin. These findings support further investigation into the comparative effectiveness and cost-effectiveness of PARPi and platinum chemotherapy in men with DDR-deficient mCRPC.

Recent clinical trials have changed the treatment landscape for metastatic castration-sensitive prostate cancer. Ongoing and future studies using new therapeutic approaches hold the promise of further improving outcomes for patients with advanced prostate cancer.

Prostate cancers are considered immunologically ‘cold’ tumors as they have demonstrated poor response to check-point inhibitor therapy (CPI). Recently, enrichment of interferon response genes suggests a favorable response to CPI across various disease sites. The enhancer of zeste homolog-2 (EZH2) is over-expressed in prostate cancer and is known to negatively regulate IFN response genes. Here, we demonstrate that inhibition of EZH2 catalytic activity in prostate cancer models increases expression of double-strand RNA (dsRNA), that is associated with upregulation of genes connected with antigen presentation, Th-1 chemokine signaling, and interferon (IFN) response genes, including PD-L1. Likewise, application of a novel EZH2 derived gene signature and TMA analysis indicated an inverse correlation between tumor EZH2 activity/expression with, T-cell inflamed and IFN gene signatures, and PD-L1 expression in human prostate cancer samples. EZH2 inhibition combined with PD-1 CPI significantly enhances anti-tumor response that is dependent on up-regulation of tumor PD-L1 expression. Further, combination therapy significantly increases intratumoral trafficking of activated CD8+ T-cells and M1 tumor associated macrophages (TAMs) with concurrent loss of M2 TAMs. Our study identifies EZH2 as a potent inhibitor of antitumor immunity and responsiveness to CPI. This data suggests EZH2 inhibition as a novel therapeutic direction to enhance prostate cancer response to PD-1 CPI. Citation Format: Anjali Sheahan, Katherine Morel, Deborah Burkhart, Sylvan Baca, David Labbè, Keven Roehle, Carla Calagua, Huihui Ye, Phillip Galbo, Sukanya Panja, Antonina Mitrofanova, Anis Hamid, Adam Kibel, Atish Choudhury, Mark Pomerantz, Matthew Freedman, Christopher Sweeney, Stephanie Dougan, Adam Sowalsky, Brian Olson, Massimo Loda, Leigh Ellis. Targeting EZH2 increases therapeutic efficacy of PD-1 blockade in models of prostate cancer [abstract]. In: Proceedings of the AACR-NCI-EORTC International Conference on Molecular Targets and Cancer Therapeutics; 2019 Oct 26-30; Boston, MA. Philadelphia (PA): AACR; Mol Cancer Ther 2019;18(12 Suppl):Abstract nr B006. doi:10.1158/1535-7163.TARG-19-B006

Background: Inflammation, mediated by NF-κB, is linked to prostate cancer (PCa) progression and is commonly observed in castrate-resistant disease. We have previously shown that low expression of tristetraprolin (TTP), which modulates the NF-κB pathway and inflammation, is prognostic for lethal PCa after surgery. It has been suggested that NF-κB-driven resistance in PCa cells may be mediated by aberrant androgen receptor (AR) activation and AR splice variant production. Reversal of resistance to androgen deprivation therapy (ADT) may therefore be achieved by utilizing NF-κB inhibitors, such as dimethylaminoparthenolide (DMAPT). Materials and Methods: To examine clinical correlations between TTP/NF-κB and AR-V7, gene-expression profiling data and clinical data was obtained from several publicly available PCa cohorts (TCGA, SU2C, Taylor et. al.). Quantitative immunofluorescence for TTP and PTEN was performed on tissue microarrays from a clinical cohort of patients treated by radical prostatectomy with known time to biochemical recurrence (BCR). In vitro, mouse (MYC-CaP) and human (VCaP-CR, LNCaP-95) PCa cell lines were treated with TNF-α (20 ng/mL) to stimulate NF-κB expression, DMAPT (5-10 μM) to inhibit NF-κB and Enzalutamide (10 μM) in various combinations. Cell lines stably expressing the IκBα super repressor (MUT IκBα) were generated for comparison to DMAPT-mediated inhibition of NF-κB. Expression of AR and AR variants was measured by western blot and qPCR. For in vivo experiments, SCID mice bearing VCaP-CR xenograft tumors were treated with surgical castration, DMAPT (100 mg/kg, oral gavage, QD), surgical castration plus DMAPT or water vehicle control (n = 7-8 per group). Xenograft tumors were measured thrice weekly until they reached an ethical endpoint or after 80 days of treatment. Time-to-progression of tumors was assessed by Kaplan-Meier analysis and molecular differences within tumors analyzed by qPCR and immunohistochemistry (IHC). Results: In multiple clinical PCa cohorts, reduced TTP expression correlated with an increased AR-V7 signature. In a cohort of patients with localized PCa, decreased TTP expression reduced time to BCR and co-loss of TTP and PTEN (a known PCa tumor suppressor) further decreased time to BCR. Activation of NF-κB in PCa cell lines resulted in a significant increase in AR variant expression and minor upregulation of AR. Chemical (DMAPT) and genetic (MUT IκBα) inhibition of NF-κB slowed tumor proliferation and decreased AR variant expression. Treatment of PCa cell lines with Enzalutamide resulted in AR variant upregulation, which was blocked by DMAPT. Castration of mice bearing VCaP-CR tumors significantly increased AR and AR-V7 tumor expression. DMAPT treatment reduced NF-κB and AR-V7 expression in xenograft tumors, but did not significantly alter tumor growth compared to vehicle treatment. The combination of castration and DMAPT slowed median time-to-progression of xenograft tumors compared to vehicle-treated tumors (79 and 36 days respectively, p < 0.001). Combination therapy decreased Ki-67 (IHC), AR-V7 and AR (IHC and qPCR) expression in xenograft tumors. Conclusions: Current treatments for PCa mainly target AR; however, despite initial response, these treatments commonly fail. Our data highlight the relationship between NF-κB and AR variant expression in aggressive PCa and support the rationale for clinical use of DMAPT to treat castrate-resistant tumors in combination with AR antagonists. Citation Format: Katherine L Morel, Anis A Hamid, Leigh Ellis, Christopher J Sweeney. Dimethylaminoparthenolide-mediated inhibition of NF-κB decreases resistance to ADT by targeting AR variants in lethal prostate cancer [abstract]. In: Proceedings of the AACR-NCI-EORTC International Conference on Molecular Targets and Cancer Therapeutics; 2019 Oct 26-30; Boston, MA. Philadelphia (PA): AACR; Mol Cancer Ther 2019;18(12 Suppl):Abstract nr B038. doi:10.1158/1535-7163.TARG-19-B038

PTEN deletion is associated with relapse after therapy for localized prostate cancer. There are limited data on PTEN loss as detected by immunohistochemistry (IHC) and the risk of lethal disease after surgery.To determine whether PTEN loss as detected by quantitative fluorescence IHC (FIHC) predicts lethal disease outcomes after surgery for prostate cancer.We used formalin-fixed, paraffin-embedded radical prostatectomy specimens to construct tissue microarrays and perform dual FIHC for PTEN and AMACR for masking tumor epithelium, plus semi-quantitative multispectral imaging analysis.The association of PTEN status analyzed continuously and dichotomously (low [expression in the lowest quartile] vs higher [expressionlowest quartile]) with disease outcomes (metastasis and death) was assessed with adjustment for age, Gleason score, and stage in multivariable analyses. The prognostic ability of PTEN was assessed using logistic regression models.Low PTEN expression was associated with a higher risk of metastatic disease as both a continuous (hazard ratio [HR] 1.49, 95% confidence interval [CI] 1.14-1.92; p0.003) and dichotomous (HR 1.92, 95% CI 1.02-3.63; p=0.04) variable. A significant association between low PTEN expression and poorer overall survival was observed (continuous: HR 1.89, 95% CI 1.37-2.63; p0.001; dichotomous: HR 2.66, 95% CI 1.34-5.28; p=0.005). Addition of PTEN status to clinicopathologic factors (age, Gleason score, and stage) incrementally improved a prognostic model assessing 10-yr outcomes for metastatic disease (area under the curve [AUC] 0.76 vs 0.80) and death (AUC 0.70 vs 0.75).Low PTEN expression detected by FIHC in primary prostate cancer is an independent prognostic biomarker for metastatic disease and death after definitive therapy. FIHC for PTEN is a viable clinical diagnostic assay in this context.We looked at loss of the PTEN protein in prostate tumors from men treated with surgery. Men with PTEN loss were at higher risk of metastasis and death. Assessing PTEN status may be useful in better determination of the risk of poorer outcomes.

Background High-dose chemotherapy (HDCT) with autologous stem-cell transplantation (aSCT) has been a standard therapy for relapsed metastatic germ-cell tumors (GCTs) over the last 2 decades, but there have been many changes in practice over time with respect to stem-cell source, mobilization, and conditioning regimens. Mobilization is impaired with greater cisplatin exposure. Patients and Methods Patients with relapsed GCT who received HDCT/aSCT at Dana-Farber Cancer Institute between 1997 and 2017 were identified. Diagnosis, first-line chemotherapy, stem-cell mobilization, HDCT, toxicity, and survival outcomes were annotated and descriptively summarized. Univariable associations of clinicopathologic features and relapse and survival were assessed. Time-to-event analyses were performed by HDCT type and duration. Results Thirty-five eligible patients were identified. The most common regimen before HDCT was paclitaxel, ifosfamide, and cisplatin, and it resulted in a high rate of successful initial mobilization (95%). Ten patients (29%) were mobilized with filgrastim and plerixafor (CXCR4 antagonist). All plerixafor-treated patients were mobilized with sufficient cells for 2 transplants. Oxazaphosphorine (cyclophosphamide or ifosfamide)-containing (O-C) HDCT was provided between 1997 and 2008, and subsequent patients were treated with high-dose carboplatin plus etoposide (CE). O-C HDCT was associated with excessive cardiac (33%), severe liver (93%), and renal dysfunction compared to CE. Two O-C–treated patients died of drug-related lung toxicity. Fifty-one percent of the cohort experienced relapse, and 46% died. Conclusion Plerixafor has a role in stem-cell mobilization and aSCT for relapsed GCT when cisplatin in bridging before HDCT may be problematic. O-C and CE HDCT regimens have different toxicity patterns that are clinically meaningful.

Background: Communication of prognosis and goals of care between oncologists, community health care providers (HCPs) and patients treated for advanced cancer facilitates optimal care planning. We aimed to review the frequency, content and timing of documented prognosis in written correspondence during the last year of life of advanced cancer patients. Methods: All patients who died during palliative care or medical oncology admission in 2015 at a large, Australian tertiary center were identified. Patients with incurable solid organ cancer and reviewed ≥1 times in oncology outpatient (OP) clinic were included. We reviewed all oncology OP consultation notes and letters, oncology discharge summaries and advanced care plans over a 12-month period before death. Both internal (OP notes) and external correspondence (OP letters; discharge summaries) were reviewed for documentation of qualitative and quantitative prognosis. Results: One hundred and forty-seven patients were included in the analysis [median age of 70 years, interquartile range (IQR), 58–77 years; males, 60%]. Most patients had a previous inpatient admission (73%). The median OP consultations per patient was 6 (IQR, 2–9) with a median rate of 63% (IQR, 41–87%) resulting in a correspondence letter. The majority of patients had a qualitative statement of prognosis documented in OP notes (63%) and external correspondence letters (61%). However only a minority had a documented quantitative prognosis in either OP notes (14%) or external correspondence letters (7%). The median time from documentation of qualitative and quantitative prognosis to death was 3.5 (IQR, 1.6–6.9) and 2.2 (IQR, 1.1–4.4) months, respectively. While almost all patients had a completed goals-of-care (GOC) form (99%), only 15% of patients had an advanced care plan. Conclusions: Documentation of qualitative and quantitative prognosis is infrequent despite multiple clinical encounters prior to patient death. This infers inadequate communication between oncologists and other HCPs which reduces insight into patient clinical trajectory and could result in differing care between providers.

e16601 Background: We previously showed that loss of PTEN by quantitative multiplex immunofluorescence (qIF) is associated with relapse after prostatectomy. Low expression of TTP, which modulates the NF-kB pathway and inflammation, is prognostic for lethal PrCa after surgery. We also showed, with this assay, that low CD8+ density is a poor prognostic marker. We hypothesized that co-loss of these independent cell signaling regulators leads to poorer outcomes, and low TTP is associated with a modified tumor immune microenvironment. Methods: qIF was performed on tissue microarrays from a cohort treated by radical prostatectomy (N = 128). PTEN and TTP expression intensity was measured continuously at a cell-by-cell level and summarized per patient using binary thresholds. Immune marker (CD3, CD8, PD-L1, PD-1, FOXP3) density (positive cells/area) was evaluated in glands and stroma. Median time to biochemical recurrence (BCR) and metastasis (MFS) was estimated using Kaplan Meier method and log rank test summarized associations between expression and time to event outcomes. Wilcoxon test assessed the association of biomarker status and immune marker density. Results: Of 128 patients with a median follow-up of 14.6 years, 67 (52%) had BCR. 102 had staining for PTEN, 103 for TTP and 86 for both. Key findings are detailed in Table. PTEN and TTP co-loss was associated with the shortest time to BCR and worst MFS. TTP-low tumors had an immune infiltrate deplete of CD8 (p = 0.0004) and PD-1 (p = 0.0001) expressing cells. No significant differences in immune markers were noted by PTEN status. Conclusions: Co-loss of regulators of inflammation and cell cycling is associated with incremental risk of relapse in localized PrCa. Loss of TTP is associated with a diminished effector T cell infiltrate and may be a modifier towards a ‘cold’ PrCa immune microenvironment. Table: Clinical outcomes by biomarker status [Table: see text]

5018 Background: Predictive genomic biomarkers in mCRPC remain elusive. Prior studies suggest that tumor suppressor (TS) loss is prognostic, and may result in less benefit from NHT, but no impact on D efficacy. We assessed genomic predictors of differential benefit of androgen receptor-targeted therapy and chemotherapy for mCRPC. Methods: Patients with mCRPC and targeted exome sequencing of biopsies obtained after metastatic diagnosis were identified (n=109). Patients with pure small cell histology (n=6) were excluded. Time from NHT or D start to clinical/radiographic progression (time to treatment failure, TTTF) was estimated by Kaplan-Meier method, with censoring at next therapy or last follow-up for non-progressors. Results: 80.1% of patients had bone and/or lymph node-only metastases at mCRPC diagnosis. In total, 87/103 (84.5%) and 61/103 (59.2%) received NHT and D for mCRPC, respectively. Median overall survival was 4.5 years from first mCRPC. The frequency and predictive association of selected recurrently-altered genes are detailed in the table. PTEN alterations (alts) were associated with worse TTTF on NHT, but not D, and a similar trend was observed with BRCA2. Biallelic RB1 loss was strongly predictive, conferring significantly shorter TTTF on both NHT and D. A score based on presence of tumor PTEN alt (1) and/or biallelic RB1 alt (1) was predictive of TTTF on NHT (median TTTF of score 0 vs 1 vs 2: 14.7 vs 12 vs 3.8 months; log rank p=0.003). Conclusions: The presence of single or compound PTEN and RB1 alts predict poorer outcomes with NHT for mCRPC. Chemotherapy may be a preferred therapeutic strategy for this patient population. [Table: see text]

IMPORTANCE Approximately 50% of the risk for the development of testicular germ cell tumors (TGCTs) is estimated to be heritable, but no mendelian TGCT predisposition genes have yet been identified. It is hypothesized that inherited pathogenic DNA repair gene (DRG) alterations may drive susceptibility to TGCTs. OBJECTIVE To systematically evaluate the enrichment of germline pathogenic variants in the mendelian cancer predisposition DRGs in patients with TGCTs vs healthy controls. DESIGN, SETTING, AND PARTICIPANTS A case-control enrichment analysis was performed from January 2016 to May 2018 to screen for 48 DRGs in 205 unselected men with TGCT and 27 173 ancestry-matched cancer-free individuals from the Exome Aggregation Consortium cohort in the discovery stage. Significant findings were selectively replicated in independent cohorts of 448 unselected men with TGCTs and 442 population-matched controls, as well as 231 high-risk men with TGCTs and 3090 ancestry- matched controls. Statistical analysis took place from January to May 2018. MAIN OUTCOMES AND MEASURES Gene-level enrichment analysis of germline pathogenic variants in individuals with TGCTs relative to cancer-free controls. RESULTS Among 205 unselected men with TGCTs (mean [SD] age, 33.04 [9.67] years), 22 pathogenic germline DRG variants, one-third of which were in CHEK2 (OMIM 604373), were identified in 20 men (9.8% ; 95% CI, 6.1%-14.7%). Unselected men with TGCTs were approximately 4 times more likely to carry germline loss-of-function CHEK2 variants compared with cancer-free individuals from the Exome Aggregation Consortium cohort (odds ratio [OR], 3.87 ; 95% CI, 1.65-8.86 ; nominal P = .006 ; q = 0.018). Similar enrichment was also seen in an independent cohort of 448 unselected Croatian men with TGCTs (mean [SD] age, 31.98 [8.11] years) vs 442 unselected Croatian men without TGCTs (at least 50 years of age at time of sample collection) (OR, >1.4 ; P = .03) and 231 high-risk men with TGCTs (mean [SD] age, 31.54 [9.24] years) vs 3090 men (all older than 50 years) from the Penn Medicine Biobank (OR, 6.30 ; 95% CI, 2.34- 17.31 ; P = .001). The low-penetrance CHEK2 variant (p.Ile157Thr) was found to be a Croatian founder TGCT risk variant (OR, 3.93 ; 95% CI, 1.53-9.95 ; P = .002). Individuals with the pathogenic CHEK2 loss-of-function variants developed TGCTs 6 years earlier than individuals with CHEK2 wild-type alleles (5.95 years ; 95% CI, 1.48-10.42 ; P = .009). CONCLUSIONS AND RELEVANCE This multicenter case-control analysis of men with or without TGCTs provides evidence for CHEK2 as a novel moderate-penetrance TGCT susceptibility gene, with potential clinical utility. In addition to highlighting DNA-repair deficiency as a potential mechanism driving TGCT susceptibility, this analysis also provides new avenues to explore management strategies and biological investigations for high-risk individuals.

244 Background: Treatments and outcomes of men with nmCRPC in routine care are poorly described. We assessed the cumulative impact of new therapies in men who transition through nmCRPC using a single-institution database. Methods: We conducted a retrospective study of consecutive nmCRPC pts enrolled into a hospital-based registry at Dana-Farber Cancer Institute. Pts were analyzed by era of diagnosis of nmCRPC: 2000-2009 (when docetaxel was the only life prolonging metastatic CRPC therapy) (cohort A) and 2010-2018 (when new systemic therapies were approved for mCRPC or in trials for nmCRPC) (cohort B). We collected pt, treatment, metastasis-free survival (MFS) and overall survival (OS) data. Results: 230 men were included: 148 in cohort A and 62 in cohort B. Despite only 39% of cohort B pts receiving new hormonal therapies for nmCRPC, there was no difference in median MFS between both eras: 2.7 yrs (2.1-3.2) in cohort A and 2.2 yrs (1.4-3.3) in cohort B. 30% of pts in cohort A and 53% of pts in cohort B had two or more life prolonging mCRPC therapies at any time (Table). No difference in 3-year OS was seen but 4-year OS was numerically higher in cohort B, with a trend towards improved OS in the new era. Conclusions: In an era with access to more than one life prolonging therapy for mCRPC, greater use of these agents in pts who transition through nmCRPC to mCRPC did not improve 3-year OS but may impact longer term OS. [Table: see text]

86 Background: Given limited information about the prostate cancer (PC) immune infiltrate in men with localized disease, we profiled 6 markers and correlated them with risk of metastases after RP, using a single-institution cohort. Methods: Using a tissue microarray (TMA) with formalin-fixed, paraffin-embedded radical prostatectomy specimens, we performed a multiplex immunohistochemistry (IHC) analysis of immune checkpoint markers (PD1, PDL1), T-cell regulator / helper (FOXP3, CD4) and killer T cells (CD3, CD8). Quantitative multispectral imaging analysis was used to define the “density” of each marker: a ratio between number of positive cells divided by glandular and stromal area. Data collected included patient characteristics, time to biochemical relapse (BCR), time to metastasis (M1) and overall survival (OS). Results: TMA staining resulted data for at least one marker for 129 patients and all 6 markers for 109 patients. Median follow-up for this cohort was 14 years (0.25-27 years). As detailed in the table, either low CD8 or high PDL1 had a statistically significant association with biochemical and metastatic relapse and trend toward poorer OS on univariate analysis (UVA). A risk score of 0, 1 or 2 with CD8 low and PDL1 high each being one point revealed a strong association with higher score and incremental risk of BCR and metastasis. Conclusions: Multiplex IHC profiling of primary prostate cancer revealed high PDL1 and low CD8 density as poor prognostic markers alone and more impactful as part of a risk score for biochemical and metastatic relapse. [Table: see text]