Checkpoint Inhibitors in Urothelial Carcinoma-Future Directions and Biomarker Selection

CONTEXT

Several recent phase 2 and 3 trials have evaluated the efficacy and toxicity of checkpoint inhibitor (CPI) therapy for urothelial carcinoma (UC) in the metastatic, localized muscle-invasive UC (MIUC), upper tract UC, and non-muscle-invasive bladder cancer (NMIBC) disease state.

OBJECTIVE

To assess the outcomes and toxicity of CPIs across the treatment landscape of UC and contextualize their application to current real-world treatment.

EVIDENCE ACQUISITION

We queried PubMed, Web of Science, and EMBASE databases and conference abstracts to identify prospective trials examining CPIs in UC. The primary endpoints included overall survival, recurrence-free survival, and toxicity (when available). A secondary analysis included biomarker evaluation of response.

EVIDENCE SYNTHESIS

We identified 21 trials, 12 phase 2 and nine phase 3 trials, in which a CPI was used for metastatic UC (seven), MIUC (nine), and NMIBC (five). For first-line (1L) metastatic UC, concurrent chemotherapy with CPIs failed to show superiority. Improved overall and progression-free survival for switch maintenance avelumab (after achieving stable disease or response with induction systemic chemotherapy) has established the current standard of care for 1L metastatic UC. A single-agent CPI is a consideration for patients unable to tolerate chemotherapy. CPIs in the perioperative setting are limited to only the adjuvant treatment with nivolumab after radical surgery for MIUC in patients at a higher risk of recurrence based on pathologic stage. Only pembrolizumab is approved by the Food and Drug Administration for carcinoma in situ unresponsive to bacillus Calmette-Guérin (BCG) in patients who are not fit for or who refuse radical cystectomy. Trials investigating CPIs in combination with multiple immune regulators, antibody drug conjugates, targeted therapies, antiangiogenic agents, chemotherapy, and radiotherapy are enrolling patients and may shape the future treatment of patients with UC.

CONCLUSIONS

CPIs have an established role across multiple states of UC, with broadened applications likely to occur in the future. Several combinations are being evaluated, while the development of predictive biomarkers and their validation may help identify patients who are most likely to respond.

PATIENT SUMMARY

Our findings highlight the broad activity of checkpoint inhibitors in urothelial carcinoma, noting the need for further investigation for the best application of combinations and patient selection to patient care.

Clinical factors associated with outcome in solid tumor patients treated with immune-checkpoint inhibitors: a single institution retrospective analysis

OBJECTIVES

Response to immune checkpoint inhibitor (ICI) remains limited to a subset of patients and predictive biomarkers of response remains an unmet need, limiting our ability to provide precision medicine. Using real-world data, we aimed to identify potential clinical prognosticators of ICI response in solid tumor patients.

METHODS

We conducted a retrospective analysis of all solid tumor patients treated with ICIs at the Mount Sinai Hospital between January 2011 and April 2017. Predictors assessed included demographics, performance status, co-morbidities, family history of cancer, smoking status, cancer type, metastatic pattern, and type of ICI. Outcomes evaluated include progression free survival (PFS), overall survival (OS), overall response rate (ORR) and disease control rate (DCR). Univariable and multivariable Cox proportional hazard models were constructed to test the association of predictors with outcomes.

RESULTS

We identified 297 ICI-treated patients with diagnosis of non-small cell lung cancer (N = 81, 27.3%), melanoma (N = 73, 24.6%), hepatocellular carcinoma (N = 51, 17.2%), urothelial carcinoma (N = 51, 17.2%), head and neck squamous cell carcinoma (N = 23, 7.7%), and renal cell carcinoma (N = 18, 6.1%). In multivariable analysis, good performance status of ECOG ≤ 2 (PFS, ORR, DCR and OS) and family history of cancer (ORR and DCR) associated with improved ICI response. Bone metastasis was associated with worse outcomes (PFS, ORR, and DCR).

CONCLUSIONS

Mechanisms underlying the clinical predictors of response observed in this real-world analysis, such as genetic variants and bone metastasis-tumor microenvironment, warrant further exploration in larger studies incorporating translational endpoints. Consistently positive clinical correlates may help inform patient stratification when considering ICI therapy.

Characterization of urine-derived immune cells from bladder cancer patients and comparison to tumor and peripheral blood

Background

Although PD-1/PD-L1 immune checkpoint blockade (ICB) therapy has achieved durable clinical responses in a subset of bladder cancer patients (15–25%), the majority do not respond. This has led to a need to identify clinically predictive biomarkers. Urine is an accessible material that may reflect cellular and/or genetic signatures related to ICB response. It has been shown that bladder cancer patient urine contains immune cells in addition to tumor cells. To study the concordance between urinary immune cells and the tumor immune microenvironment (TIME), we un-biasedly characterized bladder cancer patient urine and compared it to tumor and peripheral blood mononuclear cells (PBMC).

Methods

Matched tumor, urine, and PBMC from 8 bladder cancer patients were dissociated for single cell RNA sequencing (scRNAseq) and Cellular Indexing of Transcriptomes and Epitopes by Sequencing (CITE-seq) using 10X Genomics.

Results

scRNAseq of bladder cancer patient urine revealed CD4+ and CD8+ T, T regulatory (Treg), natural killer (NK), and B cells as well as neutrophils, dendritic cells, monocytes, and macrophages. The composition and transcriptional profiles of these cells were more similar to the tumor immune cells than to PBMC. Urine immune cells expressed hypoxia, anergy, and pro-inflammatory gene signatures that were more similar to tumor immune cells than PBMC.

Conclusions

Our work represents the first scRNAseq and CITE-seq of cancer patient urine. Our study shows several immune cells shed in bladder cancer patient urine and suggests they look phenotypically similar to the TIME. This has implications for future clinical applications as urine can be sampled non-invasively in scenarios when tumor resection may not be feasible.

Supported by the NIH grant: R01 CA249175-01.  

Usability Inspection of a Mobile Cancer Telerehabilitation System

Cancer rehabilitation (CR) has been shown to address physical impairments and progressive disablement experienced by patients with cancer. Access to CR is limited by multiple barriers. Previous studies demonstrated that telemedicine approaches may facilitate access to rehabilitation services however usability and acceptance of cancer telerehabilitation has not been systematically evaluated. This goal of this study was usability inspection of a mobile cancer telerehabilitation system based on cognitive walkthroughs and heuristics evaluations, supplemented by surveys to capture health literacy, patient engagement, and acceptance. The System Usability Scale provided a standardized reference for usability and satisfaction, and the mean result of 83.2±16.9 placed this mobile interface in the top 10th percentile. A semi-structured qualitative interview provided actionable feedback, which informed the next iteration of this project. Overall, this mobile telerehabilitation system was considered by cancer patients easy-to-use, satisfying, and engaging with 91% of participants planning to use it in the future.

314 NKG2A and HLA-E define a novel alternative immune checkpoint axis in bladder cancer

Background

Bladder cancer is characterized by a poor prognosis, with muscle-invasive cases harboring a 34–76% 10-year recurrence-free survival rate.1 Neoadjuvant PD-1/PD-L1 blockade strategies have recently been approved by the US Food and Drug Administration for bladder cancer treatment, yet only achieving a complete response rate of 31–37%, thereby suggesting additional mechanisms of resistance.2 HLA-E is a known inhibitor of NKG2A+ CD8 T cells and NK cell responses. A monoclonal antibody binding to the NKG2A receptor has been developed and proven to restore CD8 T cell and NK cell responses in head and neck cancer, with ongoing clinical trials across multiple tumor indications.3 4 We evaluated the potential role of the HLA-E/NKG2A inhibitory pathway in modulating T cell immunity in bladder cancer.

Methods

CyTOF was performed on CD8+ T cells from fresh bladder tumors (n=6), as well as on expanded CD8+ T cells from bladder-draining lymph nodes (n=11) and tumors (n=8). Flow cytometry (n=25) and single-cell RNA-sequencing (scRNAseq) (n=13) were performed on cells from fresh bladder tumors.

Results

Mechanisms of tumor escape from CD8+ T cell recognition include impairment of antigen presentation. Accordingly, we found a significant reduction of HLA class I expression on tumors. However, expression of DNAM-1-activating ligands (e.g. CD112,CD155) on bladder tumors was retained, indicating a possible role for TCR-independent activation pathways traditionally ascribed to natural killer (NK) cells. Using mass cytometry and scRNAseq, we observed that acquisition of NKG2A on tumor-derived PD-1+ CD8+ T cells promotes tissue-resident memory features alongside diminished CD28 expression and significantly weaker sensitivity to CD3/CD28-signaling. However, NKG2A+ CD8 T cells possess a proliferative advantage with enhanced expression of DNAM-1 and cytolytic machinery.Strikingly, we found that NKG2A+PD-1+ CD8 T cells are strongly activated in response to HLA class I-deficient tumors compared to their NKG2A- PD-1+ CD8 T cell counterparts. TCR-independent NK-like function by NKG2A+ CD8 T cell is partly mediated by the DNAM-1 pathway and inhibited by HLA-E. NKG2A+ CD8 T cell functions are restored upon NKG2A blockade, where efficiency positively correlates with HLA-E expression on bladder tumors.

Conclusions

Collectively, our data indicate that NKG2A+ CD8 T cells display a strong capacity for TCR-independent activation that enables them to circumvent bladder tumor evasion mechanisms. NKG2A+ CD8 T cells lack expression of CD28 suggesting a lower susceptibility to PD-1-mediated inhibiton. Our data suggest a need for thorough reappraisal of current protocols that assess CD8 T cell exhaustion and for strategies to restore their antitumor functions.

References

Sanli O, Dobruch J, Knowles MA, Burger M, Alemozaffar M, Nielsen ME, Lotan Y. Bladder cancer. Nat Rev Dis Primers 2017 April 13;3:17022. doi: 10.1038/nrdp.2017.22. PMID: 28406148.

Rouanne M, Bajorin DF, Hannan R, Galsky MD, Williams SB, Necchi A, Sharma P, Powles T. Rationale and outcomes for neoadjuvant immunotherapy in urothelial carcinoma of the bladder. Eur Urol Oncol 2020 December;3(6):728–738. doi: 10.1016/j.euo.2020.06.009. Epub 2020 Nov 8. PMID: 33177001.

André P, Denis C, Soulas C, Bourbon-Caillet C, Lopez J, Arnoux T, Bléry M, Bonnafous C, Gauthier L, Morel A, Rossi B, Remark R, Breso V, Bonnet E, Habif G, Guia S, Lalanne AI, Hoffmann C, Lantz O, Fayette J, Boyer-Chammard A, Zerbib R, Dodion P, Ghadially H, Jure-Kunkel M, Morel Y, Herbst R, Narni-Mancinelli E, Cohen RB, Vivier E. Anti-NKG2A mAb is a checkpoint inhibitor that promotes anti-tumor immunity by unleashing both T and NK Cells. Cell 2018 December 13;175(7):1731–1743.e13. doi: 10.1016/j.cell.2018.10.014. Epub 2018 Nov 29. PMID: 30503213; PMCID: PMC6292840.

van Hall T, André P, Horowitz A, Ruan DF, Borst L, Zerbib R, Narni-Mancinelli E, van der Burg SH, Vivier E. Monalizumab: inhibiting the novel immune checkpoint NKG2A. J Immunother Cancer 2019 October 17;7(1):263. doi: 10.1186/s40425-019-0761-3. PMID: 31623687; PMCID: PMC6798508.

621 NKG2A and HLA-E define a novel mechanism of resistance to immunotherapy with M. bovis BCG in non-muscle-invasive bladder cancer patients

Background

75% of diagnosed bladder tumors are non-muscle-invasive (NMIBC)[1, 2]. Most require intravesical instillation of M.bovis Bacillus Calmette-Guérin (BCG). Recurrence after immunotherapy occurs in ~50% patients. Development of treatments for BCG-resistant disease has lagged partly because few studies have attempted to understand the relationship between timing of tumor recurrence, reasoning for the recurrence, and the state of immune system at the time of recurrence.Immune exhaustion is observed following microbial infections, cancers and chronic inflammation [3–5]. Natural Killer (NK) cells are among the earliest responders[6–8] and undergo a similar program of exhaustion as T cells[9]. HLA-E strongly inhibits NKG2A-expressing NK and CD8+T cells and is commonly upregulated on tumors[10]. We evaluated the potential restorative capacity of NKG2A and PD-L1-blockade for reinvigorating NK and CD8+T cell antitumor functions in in BCG-resistant bladder cancer.

Methods mRNA analysis of 2,892 genes was performed on tumor tissue of NMIBC patients before and after BCG therapy (n=35). Immunostaining (serial-IHC,immunofluorescence,imaging-mass cytometry) was performed on consecutive tissue sections. Single-cell-RNA-sequencing (scRNAseq) was performed on fresh bladder tumors (NMIBC,n=4; MIBC,n=9). OLink Proteomics (”Inflammation” panel) was performed longitudinally on plasma/urine from a prospective cohort of NMIBC patients. Patient tumors (n=3) were expanded as organoids and co-cultured with autologous tumor-derived NK and CD8+T cells in presence/absence of anti-PD-L1/NKG2A antibodies.

Results

We demonstrate a robust local TME and systemic response to BCG that correlates with chronic inflammation and adaptive resistance rather than with preventing tumor recurrence. This resistance is mediated through IFN-γ-production by tumor-infiltrating NKG2A+NK and NKG2A+PD-1+CD8+T cells and results in increased HLA-E and PD-L1 on recurring tumors. Co-culture of treatment-naïve NMIBC tumors with recombinant IFN-gamma directly enhanced expression of PD-L1 and HLA-E. Longitudinal analysis of plasma before and during BCG immunotherapy revealed an inflammatory signature, including but not limited to IFN-gamma, that is maintained throughout treatment.Immunostaining and scRNAseq of NMIBC specimens revealed highly enriched infiltration by NKG2A+NK and NKG2A+CD8+T cells in HLA-EBrightPD-L1+ tumors and were spatially organized relative to tumors in a manner suggesting direct inhibition. Tumor-derived NK and CD8+T cells from BCG-resistant patients were co-cultured with autologous tumor organoids. Preliminary analyses demonstrated an improved anti-tumor response in presence of NKG2A/PD-L1-blockade.

Conclusions

Our data support a model of BCG-resistance that points to a novel checkpoint axis that contributes to BCG-resistance: HLA-E/NKG2A. New insights into this axis in NMIBC and how it is altered with repeated BCG exposure will enable us to explore combination therapies (PD-L1/NKG2A-blockade) that may reduce BCG-resistance and provide durable response.

References

Eidinger D, Morales A: Discussion paper: treatment of superficial bladder cancer in man. Ann N Y Acad Sci 1976, 277:239–240.

Morales A, Eidinger D, Bruce AW: Intracavitary Bacillus Calmette-Guerin in the treatment of superficial bladder tumors. J Urol 1976, 116:180–183.

Blank CU, Haining WN, Held W, Hogan PG, Kallies A, Lugli E, Lynn RC, Philip M, Rao A, Restifo NP et al: Defining ‘T cell exhaustion’. Nat Rev Immunol 2019, 19:665–674.

Hashimoto M, Kamphorst AO, Im SJ, Kissick HT, Pillai RN, Ramalingam SS, Araki K, Ahmed R: CD8 T Cell Exhaustion in Chronic Infection and Cancer: Opportunities for Interventions. Annu Rev Med 2018, 69:301–318.

McLane LM, Abdel-Hakeem MS, Wherry EJ: CD8 T Cell Exhaustion During Chronic Viral Infection and Cancer. Annu Rev Immunol 2019, 37:457–495.

Lanier LL: NK cell receptors. Annu Rev Immunol 1998, 16:359–393.

Biron CA, Gazzinelli RT: Effects of IL-12 on immune responses to microbial infections: a key mediator in regulating disease outcome. Curr Opin Immunol 1995, 7:485–496.

Welsh RM, Jr.: Cytotoxic cells induced during lymphocytic choriomeningitis virus infection of mice. I. Characterization of natural killer cell induction. J Exp Med 1978, 148:163–181.

da Silva IP, Gallois A, Jimenez-Baranda S, Khan S, Anderson AC, Kuchroo VK, Osman I, Bhardwaj N: Reversal of NK-cell exhaustion in advanced melanoma by Tim-3 blockade. Cancer Immunol Res 2014, 2:410–422.

van Hall T, Andre P, Horowitz A, Ruan DF, Borst L, Zerbib R, Narni-Mancinelli E, van der Burg SH, Vivier E: Monalizumab: inhibiting the novel immune checkpoint NKG2A. J Immunother Cancer 2019, 7:263.

Ethics Approval

Primary urothelial bladder cancer tumor tissue was obtained after obtaining informed consent in the context of an Institutional Review Board (IRB)-approved genitourinary cancer clinical database and specimen collection protocol (IRB #10-1180) at the Tisch Cancer Institute, Icahn School of Medicine at Mount Sinai (New York, NY).

82 Single-cell RNA sequencing and CITE-Seq analysis of bladder cancer patient urine with matched tumor and peripheral blood suggests urine as a window into the tumor immune microenvironment

Background

FDA-approved immunotherapies for early and advanced stage bladder cancer have response rates of 15–65% in bladder cancer, suggesting that tumor-associated resistance mechanisms undermine their efficacy. Accordingly, there is an unmet need to identify accessible biomarkers that predict response. Urine, which is in direct contact with urothelial tumors, represents an easily accessible patient material that may reflect cellular and/or genetic signatures related to immune resistance. It has been demonstrated that urine from bladder cancer patients contains not only tumor cells, which are routinely assessed by clinical urinalyses, but also immune cells that previous studies suggest may reflect the tumor microenvironment (TME).1 However, the concordance between cells in the urine and those in bladder tumors is unknown., Here, we characterized patient urine in an unbiased fashion by performing the first single-cell RNA sequencing (scRNAseq) and Cellular Indexing of Transcriptomes and Epitopes by Sequencing (CITE-seq) on matched bladder cancer patient urine, tumor, and peripheral blood.

Methods

Matched tumor tissue, urine, and peripheral blood were collected from bladder cancer patients (n=7) during surgery; either trans-urethral resection of bladder tumor or cystectomy. All three tissues were processed to single-cell suspensions and sequenced using the 10X Genomics platform (scRNAseq: 17 samples, CITE-seq: 3 samples). These sequencing approaches permitted quantification of both transcriptomic and surface protein expression of 54,469 cells total.2 3 Analysis was performed using Seurat, Enrichr, and Monocle packages and platforms.4 5 6

Results scRNAseq of urine from bladder cancer patients revealed several immune populations including CD4+ and CD8+ T cells, Treg cells, NK cells, B cells, neutrophils, dendritic cells, monocytes, and macrophages in addition to non-hematopoietic lineages including bladder epithelial cells, neuronal cells, prostate epithelial cells, fibroblasts, myofibroblasts, and endothelial cells. The composition and transcriptional profiles of urine immune cells were more similar to TME immune cells than to peripheral blood immune cells. Urine immune cells expressed gene signatures associated with hypoxia, anergy, pro-inflammation, and glucose deprivation that were more similar to tumor immune cells than those in the peripheral blood.

Conclusions

Our work represents the first scRNAseq and CITEseq profiling of cancer patient urine. Our study suggests several viable immune cells shed in bladder cancer patient urine that look more transcriptionally and phenotypically similar to the TME than peripheral blood cells. This important finding has several implications for future research and clinical applications as urine can be sampled non-invasively in scenarios when tumor resection may not be feasible.

References

Wong YNS, Joshi K, Khetrapal P, et al. Urine-derived lymphocytes as a non-invasive measure of the bladder tumor immune microenvironment. Journal of Experimental Medicine. 2018; 215:2748–59.

Zheng GXY, Terry JM, Belgrader P, et al. Massively parallel digital transcriptional profiling of single cells. Nature Communications 2017; 8.

Stoeckius M, Hafemeister C, Stephenson W, et al. Simultaneous epitope and transcriptome measurement in single cells. Nature Methods 2017;14, 865–68.

Butler A, Hoffman P, Smibert, P, et al. Integrating single-cell transcriptomic data across different conditions, technologies, and species. Nature Biotechnology 2018; 36: 411–20.

Xie Z, Bailey A, Kuleshov MV, et al. Gene set knowledge discovery with Enrichr. Current Protocols 2021.

Trapnell C, Cacchiarelli D, Grimsby J, et al. The dynamics and regulators of cell fate decisions are revealed by pseudotemporal ordering of single cells. Nature Biotechnology 2014; 32: 381–6.

Ethics Approval

The study was approved by Mount Sinai Institution’s Ethics Board, approval number 10–1180. Participants gave informed consent before taking part in the study.

Infigratinib in Early-Line and Salvage Therapy for FGFR3-Altered Metastatic Urothelial Carcinoma

The optimal sequencing of systemic treatments for metastatic urothelial cancer (mUC) is unknown. We assessed the efficacy of infigratinib, a fibroblast growth factor receptor (FGFR) 1 to 3 inhibitor, in 67 patients with FGFR3-altered mUC by line of therapy. Objective response rates were 31% (early-line setting) and 24% (≥2nd-line setting). Infigratinib has notable activity in mUC regardless of line of therapy.

Abstract 2188: Urothelial cancer-GENOmic analysis to improve patient outcomes and research (UC-GENOME): a bladder cancer advocacy network (BCAN) led collaborative research study

The UC-GENOME study was designed to capitalize on The Cancer Genome Atlas (TCGA) findings in real world patients with metastatic urothelial carcinoma (UC) with co-equal aims: 1) to provide targeted DNA sequencing for potential clinical decision making at no cost to patients; and 2) to create a clinically annotated biorepository (including tissue, plasma, and PBMCs) for collaborative research. Patients with metastatic UC (n=209, median age 68 y, 74% male) were accrued at 8 academic medical centers between 2016-2019. We report on the first analysis of the targeted DNAseq (n=191) and total RNAseq (n=176) from FFPE specimens (n=169 overlap). Recurrently mutated genes were observed in a similar frequency to TCGA, including TP53 (54%), KMT2D (30%), ARID1A (26%) and FGFR3 (18%). Somatic variant patterns were correlated with previously annotated mutational signatures (COSMICv3), revealing a subset of tumors enriched for APOBEC signatures. Molecular subtypes were defined using the Bladder Cancer Molecular Taxonomy Group's consensus subtyping schema (Ba_Sq=54 [31%], Stroma-rich=64 [36%], LumP=26 [15%], LumU=24 [14%], LumNS=4 [2%], NE=4 [2%]). To further understand the tumor immune features and whether they correlate with durable clinical response, tumor microenvironment deconvolution was performed by applying MiXCR and immune gene signatures. An inflamed phenotype and enhanced T cell receptor richness but not clonality was observed within Ba_Sq and Stroma-rich subtypes, which also had the highest disease control rate (CR/PR + SD ~75%) to immunotherapy. The Stroma-rich subtype had the highest disease control rate (~88%) to chemotherapy. Future efforts will leverage the clinical, DNA and RNAseq data along with other biobanked specimens for collaborative research initiatives.

Citation Format: Jeffrey S. Damrauer, Jeff Klomp, Wolfgang Beck, Mi Zhou, Elizabeth Plimack, Matthew Galsky, Petros Grivas, Noah Hahn, Peter O'Donnell, Gopa Iyer, David I. Quinn, Katherine A. Hoadley, William Y. Kim, Matthew I. Milowsky. Urothelial cancer-GENOmic analysis to improve patient outcomes and research (UC-GENOME): a bladder cancer advocacy network (BCAN) led collaborative research study [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2021; 2021 Apr 10-15 and May 17-21. Philadelphia (PA): AACR; Cancer Res 2021;81(13_Suppl):Abstract nr 2188.

Risk Factors for Emergency Room and Hospital Care Among Patients With Solid Tumors on Immune Checkpoint Inhibitor Therapy

OBJECTIVES

Immune checkpoint inhibitors (ICIs) are being increasingly used across cancer types. Emergency room (ER) and inpatient (IP) care, common in patients with cancer, remain poorly defined in this specific population, and risk factors for such care are unknown.

METHODS

We retrospectively reviewed charts for patients with solid tumors who received >1 ICI dose at 1 of 2 sites from January 1, 2011 to April 28, 2017. Demographics, medical history, cancer diagnosis/therapy/toxicity details, and outcomes were recorded. Descriptive data detailing ER/IP care at the 2 associated hospitals during ICI therapy (from first dose to 3 mo after last dose) were collected. The Fisher exact test and multivariate regression analysis was used to study differences between patients with versus without ER/IP care during ICI treatment.

RESULTS

Among 345 patients studied, 50% had at least 1 ER visit during ICI treatment and 43% had at least 1 IP admission. Six percent of ER/IP visits eventually required intensive care. A total of 12% of ER/IP visits were associated with suspected or confirmed immune-related adverse events. Predictors of ER care were African-American race (odds ratio [OR]: 3.83, P=0.001), Hispanic ethnicity (OR: 3.12, P=0.007), and coronary artery disease (OR: 2.43, P=0.006). Predictors of IP care were African-American race (OR: 2.38, P=0.024), Hispanic ethnicity (OR: 2.29, P=0.045), chronic kidney disease (OR: 3.89, P=0.006), angiotensin converting enzyme inhibitor/angiotensin receptor blocker medication use (OR: 0.44, P=0.009), and liver metastasis (OR: 2.32, P=0.003).

CONCLUSIONS

Understanding demographic and clinical risk factors for ER/IP care among patients on ICIs can help highlight disparities, prospectively identify high-risk patients, and inform preventive programs aimed at reducing such care.

Estimating the rate and reasons of clinical trial failure in urologic oncology

OBJECTIVES

Clinical trials are pillars of modern clinical evidence generation. However, the clinical trial enterprise can be inefficient, and trials often fail before their planned endpoint is reached. We sought to estimate how often urologic oncology trials fail, why trials fail, and associations with trial failure.

METHODS

We queried phase 2/3 urologic clinical trial data from ClinicalTrials.gov registered between 2007 and 2019, with status marked as active, completed, or terminated. We extracted relevant trial data, including anticipated and actual accrual, from trial records and ClinicalTrials.gov archives. We manually coded reasons given in the "why stopped" free text field for trial failure into categories (poor accrual, interim results, toxicity/adverse events, study agent unavailable, canceled by the sponsor, inadequate budget, logistics, trial no longer needed, principal investigator left, no reason given, or other). We considered trials terminated for safety or efficacy to be completed trials. Trials marked as terminated for other reasons were considered failed trials. We then estimated the rate of trial failure using competing risks methods. Finally, we assessed associations with trial failure using a Cox proportional hazards model.

RESULTS

A total of 1,869 urologic oncology trials were included. Of these, 225 (12.0%) failed, and 51 (2.7%) were terminated for "good" reasons (e.g., toxicity, efficacy). Of the 225 failed trials, 122 (54%) failed due to poor accrual. Failed trials had a lower anticipated accrual than successfully completed trials (55 vs. 63 patients, P<0.001). A total of 6,832 patients were actually accrued to failed trials. The 10-year estimated risk of trial failure was 17% (95% CI 15%-22%). Single center trials, phase 3 trials, drug trials, and trials with exclusively USA sites were more likely to fail.

CONCLUSION

We estimate that 17%, or roughly 1 in 6, of urologic oncology trials fail, most frequently for poor accrual. Further investigations are needed into systemic, trial, and site-specific factors that may impact accrual and successful trial completion.

Assessing Genitourinary Cancer Clinical Trial Accrual Sufficiency Using Archived Trial Data

PURPOSE

Clinical trials often fail to reach their anticipated end points, most frequently because of poor accrual. Prior studies have analyzed trial termination, but it has not been easy to assess accrual estimates using international databases such as ClinicalTrials.gov because of limitations in accessing accrual information. Specifically, it is not easy to extract both anticipated and actual accrual of clinical trials. We designed a new algorithmic approach to extracting trial accrual data from ClinicalTrials.gov and used it to estimate the sufficiency of patient accrual onto genitourinary (GU) cancer trials.

METHODS

We queried ClinicalTrials.gov for completed/terminated phase II and III clinical trials for prostate, bladder, kidney, testicular, and ureteral cancers registered after 2007. We extracted trial characteristics from available XML files. We then used a Python algorithm to access prior trial registrations on the ClinicalTrials.gov archive site and extract both anticipated and actual accrual numbers. We then compared the actual accrual of each trial to its anticipated accrual and defined sufficient accrual as 85% of anticipated accrual.

RESULTS

The algorithm was 100% accurate compared with hand extraction in a small validation subset. A total of 925 trials were included, of which 840 (91%) had both anticipated and actual accrual. Only 418 (50%) trials had sufficient accrual (≥ 85% of anticipated). Considering only trials marked as successfully completed, 395/597 (66%) reached sufficient accrual.

CONCLUSION

GU cancer trials often do not meet their anticipated accrual goals. New approaches to trial conduct are direly needed. Our reproducible and scalable approach to extracting accrual information can be applied to analysis of ClinicalTrials.gov in future analyses in the hope of improving the efficiency of the clinical trials enterprise.

Hyperphosphatemia Secondary to the Selective Fibroblast Growth Factor Receptor 1-3 Inhibitor Infigratinib (BGJ398) Is Associated with Antitumor Efficacy in Fibroblast Growth Factor Receptor 3-altered Advanced/Metastatic Urothelial Carcinoma

BACKGROUND

Infigratinib (BGJ398) is a potent, selective fibroblast growth factor receptor (FGFR) 1-3 inhibitor with significant activity in metastatic urothelial carcinoma (mUC) bearing FGFR3 alterations. It can cause hyperphosphatemia due to the "on-target" class effect of FGFR1 inhibition.

OBJECTIVE

To investigate the relationship between hyperphosphatemia and treatment response in patients with mUC.

INTERVENTION

Oral infigratinib 125 mg/d for 21 d every 28 d.

DESIGN, SETTING, AND PARTICIPANTS

Data from patients treated with infigratinib in a phase I trial with platinum-refractory mUC and activating FGFR3 alterations were retrospectively analyzed for clinical efficacy in relation to serum hyperphosphatemia. The relationship between plasma infigratinib concentration and phosphorous levels was also assessed.

OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS

Clinical outcomes were compared in groups with/without hyperphosphatemia.

RESULTS AND LIMITATIONS

Of the 67 patients enrolled, 48 (71.6%) had hyperphosphatemia on one or more laboratory tests. Findings in patients with versus without hyperphosphatemia were the following: overall response rate 33.3% (95% confidence interval [CI] 20.4-48.4) versus 5.3% (95% CI 0.1-26.0); disease control rate 75.0% (95% CI 60.4-86.4) versus 36.8% (95% CI 16.3-61.6). This trend was maintained in a 1-mo landmark analysis. Pharmacokinetic/pharmacodynamic analysis showed that serum phosphorus levels and physiologic infigratinib concentrations were correlated positively. Key limitations include retrospective design, lack of comparator, and limited sample size.

CONCLUSIONS

This is the first published study to suggest that hyperphosphatemia caused by FGFR inhibitors, such as infigratinib, can be a surrogate biomarker for treatment response. These findings are consistent with other reported observations and will need to be validated further in a larger prospective trial.

PATIENT SUMMARY

Targeted therapy is a new paradigm in treating bladder cancer. In a study using infigratinib, a drug that targets mutations in a gene called fibroblast growth factor receptor 3 (FGFR3), we found that elevated levels of phosphorous were associated with greater clinical benefit. In the future, these data may help inform treatment strategies.

SAT-411 Vitamin D Levels and Risk of Thyroid Immune Related Adverse Events in Patients on Immune Checkpoint Inhibitors

Immune checkpoint inhibitors (ICI), such as monoclonal antibodies to cytotoxic T lymphocyte associated protein 4 (CTLA-4), programmed cell death 1 (PD-1) and PD ligand 1 (PD-L1) are recognized as effective cancer-directed therapies. Yet, ICI-induced activation of the immune system results in immune-related adverse events (irAEs) affecting many organs, including the thyroid. Separately, Vitamin D (Vit D) deficiency has been associated with increased risk of autoimmune thyroid disease. We hypothesized that patients who were Vit D deficient at the time of initiating ICI therapy would be more likely to develop thyroid irAEs. We retrospectively collected data for 411 patients who received ICIs at our institution between January 2011 and April 2017. We then identified 91 of these patients who had 25-OH Vit D levels obtained; 2 were excluded from analysis due to previous thyroidectomy. We recorded demographics, cancer type, Vit D level closest to the start date of ICI therapy, and thyroid irAEs. Patients were categorized as Vit D deficient (&lt;20ng/mL), insufficient (20-29.9ng/mL) or sufficient (≥30ng/mL). We compared patient demographic and clinical characteristics between the VitD categories. Proportions were compared using Fisher’s Exact Test. Of the 89 patients, 48.3% were female and 51.7% were male. Mean age was 67.2 (SD±10.6) years with 57% white, 8% black, 10% hispanic, 7% Asian, and 18% other / unknown. 20% of patients had non-small cell lung cancer, 15% melanoma, 13% hepatocellular carcinoma, 12% multiple myeloma (MM), 8% renal cell carcinoma (RCC), 7% head and neck squamous cell carcinoma, 7% urothelial carcinoma and 18% other cancer types. 21.3% were Vit D deficient, 40.4% were insufficient, and 38.2% were sufficient. Patients with Vit D deficiency and insufficiency were younger (age 64.1± 11.7, 65.9±9.5 years, respectively) than the Vit D sufficiency group (70.1±10.5years, p=0.046). No significant differences between males and females were observed between Vit D categories. Across cancer types, the highest prevalence of Vit D deficiency was in RCC (42.9%) and MM (36.4%). Hispanic and Asian patients had the highest prevalence of Vit D deficiency (44.4% and 33.3%, respectively). 11 patients (12.4%) developed a thyroid irAE. Thyroid irAEs occurred in 5.3% with Vit D deficiency, 8.1% with Vit D insufficiency, and 20% with Vit D sufficiency, but the association was not statistically significant (p=0.2). In contrast to our hypothesis, Vit D deficiency was not associated with a higher rate of thyroid irAEs. In fact our data suggest that patients who are vitamin D sufficient at the time of starting ICI therapy may be at greater risk of developing thyroid irAEs. Our study is limited by small numbers and the retrospective nature of the study. Prospective studies should be performed to determine the significance of Vit D levels on ICI related thyroid disease.

Protein phosphatase 2A activation as a therapeutic strategy for managing MYC-driven cancers

The tumor suppressor protein phosphatase 2A (PP2A) is a serine/threonine phosphatase whose activity is inhibited in most human cancers. One of the best-characterized PP2A substrates is MYC proto-oncogene basic helix-loop-helix transcription factor (MYC), whose overexpression is commonly associated with aggressive forms of this disease. PP2A directly dephosphorylates MYC, resulting in its degradation. To explore the therapeutic potential of direct PP2A activation in a diverse set of MYC-driven cancers, here we used biochemical assays, recombinant cell lines, gene expression analyses, and immunohistochemistry to evaluate a series of first-in-class small-molecule activators of PP2A (SMAPs) in Burkitt lymphoma, KRAS-driven non-small cell lung cancer, and triple-negative breast cancer. In all tested models of MYC-driven cancer, the SMAP treatment rapidly and persistently inhibited MYC expression through proteasome-mediated degradation, inhibition of MYC transcriptional activity, decreased cancer cell proliferation, and tumor growth inhibition. Importantly, we generated a series of cell lines expressing PP2A-dependent phosphodegron variants of MYC and demonstrated that the antitumorigenic activity of SMAPs depends on MYC degradation. Collectively, the findings presented here indicate a pharmacologically tractable approach to drive MYC degradation by using SMAPs for the management of a broad range of MYC-driven cancers.

Budget Impact Of Including Avelumab As A Second-Line Treatment For Locally Advanced Or Metastatic Urothelial Cancer In The United States: Commercial And Medicare Payer Perspectives

OBJECTIVE

To estimate the budget impact of introducing avelumab as a second-line (2L) treatment option for patients with locally advanced or metastatic urothelial cancer (mUC) from the perspective of a US third-party payer (commercial and Medicare).

METHODS

A budget impact model (BIM) with a three-year time horizon was developed for avelumab. Efficacy and safety data were sourced from published literature and US package inserts. The analysis was conducted in collaboration with a specialist oncologist who validated clinical assumptions. Costs were based on the number of eligible patients, time-to-treatment failure, overall survival, adverse events (AEs), and projected market shares of various treatments.

RESULTS

In a hypothetical commercial health plan of 30,000,000 members, 884 patients were estimated to be eligible for 2L treatment over a three-year time period. Without avelumab, the total cost for treating patients with mUC was estimated to be US$70,268,035. The introduction of avelumab increased total costs by $73,438 (0.10% increase). In a hypothetical Medicare health plan of 30,000,000 beneficiaries, a total of 4,705 patients were estimated to be eligible for 2L treatment. Without avelumab, the total cost for treating patients with mUC was estimated to be $292,923,098 from a Medicare perspective; however, with avelumab, there was an increase of $719,324 (0.25% increase) in total costs. Results of the sensitivity analyses demonstrated a cost-neutral impact across all tested scenarios from both perspectives.

CONCLUSION

The BIM estimated that avelumab would have a cost-neutral impact within a US commercial and a Medicare health plan. Overall, avelumab can be an affordable and valuable treatment option for patients with locally advanced or mUC in the 2L setting. These findings demonstrate a consistently favorable budget impact in both populations. Further studies should be conducted to more comprehensively assess the clinical and economic implications of adding avelumab to the treatment armamentarium of 2L mUC.

Recovery from secondary adrenal insufficiency in a patient with immune checkpoint inhibitor therapy induced hypophysitis

Background

Hypophysitis is a well-recognized immune-related adverse event in patients treated with immune checkpoint inhibitors for cancer. Some anterior pituitary hormones may recover; however, secondary adrenal insufficiency is usually permanent.

Case presentation

A 26-year old male with metastatic clear cell renal cell carcinoma was started on treatment with the anti-programmed cell death-1 monoclonal antibody (anti-PD-1 mAb) nivolumab, followed by combined nivolumab and the anti-cytotoxic T-lymphocyte-associated protein 4 (CTLA-4) mAb, ipilimumab. After starting nivolumab monotherapy the patient developed thyroiditis, which resolved without treatment. Prior to commencing combined ICI therapy, a random serum cortisol drawn at 1:30 pm and was 15.0 μg/dL (414 nmol/L). Three weeks after starting combined ICI therapy he developed sudden onset of severe fatigue and 1 pm serum cortisol was 2.0 μg/dL (55.2 nmol/L), adrenocorticotropic hormone (ACTH) was 16 pg/mL (3.52 pmol/L). A diagnosis of hypophysitis was made, and he was immediately started on prednisone 1 mg/kg. His symptoms resolved rapidly, and he continued immune checkpoint inhibitor therapy. He was noted to also have low gonadotropic hormones and testosterone (nadir testosterone 81.19 ng/dL). The prednisone was tapered slowly over the next six weeks to a maintenance dose of 5 mg daily. Four months after the initial presentation his cortisol remained low, but his testosterone level had increased to 973.43 ng/dL. After five months his random serum cortisol (1 pm) increased to 11.0 μg/dL (303.6 nmol/L). The prednisone was cautiously discontinued with close monitoring. Two months off glucocorticoid replacement he remained asymptomatic with an ACTH of 24.1 pg/mL (5.3 pmol/L), and cortisol of 13.0 μg/dL (358.8 nmol/L).

Conclusions

This case documents the unusual recovery from secondary adrenal insufficiency in a patient who developed hypophysitis from immune checkpoint inhibitor therapy. Repeated pituitary hormone testing every three months for the first year after the development of hypophysitis may identify more patients with hypothalamic-pituitary-adrenal axis recovery.

Abstract CT096: Phase I study of in situ autologous vaccination for prostate cancer in a neo-adjuvant setting

Background:

Certain solid malignancies like prostate cancer pose two major challenges for effective immunotherapy. The inherently low mutation load and spatial and temporal intra-tumor heterogeneity yields an immune exclusion and development of an “immune desert” within the tumor micro-environment (TME). Additionally, there is a response failure to immunomodulation, due to tumor/patient immunosuppressive mechanisms. In an effort to transform the prostate tumor environment into an immunogenic ecosystem, we are using PolyIC:LC as an immunemodulator. The novelty of this approach is a “host targeted”, in-situ “autovaccination” strategy, which uses the patient’s own tumor as the antigen source leading to activation of both an innate and adaptive immune response. As all patients will have their cancer removed after investigational therapy we can study baseline versus treatment induced changes in bio-specimens collected before, during, and after patients are exposed to PolyIC:LC. Correlative studies include characterization of tissue and systemic biomarkers of response using multiple platforms like cytometry by time of flight (CyTOF), RNA-seq, whole exome sequencing, seromics, TCR-sequencing, neoantigen specific T-cell responses, as well as assessing circulating tumor DNA (ctDNA) at multiple time points to determine the potential in detecting tumor response to immunemodulation.

Methods:

This is a Phase I dose escalation study (NCT03262103) seeking to determine a safe dose and schedule of intratumoral (IT) plus intramuscular (IM) PolyIC:LC injections prior to radical prostatectomy in patients with prostate cancer. The dose and frequency of IT PolyIC:LC will be increased in successive cohorts using a 3+3 design and traditional dose escalation rules. The dose and schedule of IM PolyIC:LC will remain fixed in successive cohorts. The study will consist of 24 enrolled subjects, recruited into cohorts consisting of a minimum of 3 and maximum of 6 patients per cohort. The first cohort, consisting of three patients, has been completed. Recruitment for the second cohort has begun with two patients already enrolled. The inclusion criteria extend to patients diagnosed with high risk (Gleason 7-10, cT2a-cT3b) clinically localized prostate cancer with no prior hormonal or radiation therapy and with plans to undergo radical prostatectomy. Week 1 serves as the priming course with the patient coming in for a pre-treatment biopsy followed by an IT injection. Weeks 3-6 consist of a booster treatment course with IM injections two times a week. Weeks 7-9 are a rest period with no injections followed by radical prostatectomy at week 10. Blood is drawn at weeks 1, 3, 6, and 9. At the time of surgery, blood, tissue, and lymph node are collected for research purposes. Following each IT and IM injection, the subject remains in clinic for monitoring for at least 1 hour or 30 minutes respectively. Patients are seen 6 weeks post-prostatectomy as per standard of care. The next follow-up visit is approximately 3 months following surgery where the first post-operative PSA check is performed. Assuming PSA levels are undetectable, the patient is followed up at routine intervals for PSA testing.

Citation Format: Sujit S. Nair, Rachel Weil, Elena Gonzalez-Gugel, Marcia Meseck, Alex Rubinsteyn, Yulia Kodysh, Akriti Gupta, Keerthi Sadanala, Kacie Schlussel, Kamala Bhatt, Avinash Reddy, Rajan Patel, Tin Thawte, Adam Farkas, Siarhei Dzedzik, Kenneth Haines, Julia Wagner, Macy Robison, Cynthia Knauer, Andres Salazar, Matthew Galsky, Nina Bhardwaj, Ashutosh Tewari. Phase I study of in situ autologous vaccination for prostate cancer in a neo-adjuvant setting [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr CT096.

Prostate Cancer in World Trade Center Responders Demonstrates Evidence of an Inflammatory Cascade

An excess incidence of prostate cancer has been identified among World Trade Center (WTC) responders. In this study, we hypothesized that WTC dust, which contained carcinogens and tumor-promoting agents, could facilitate prostate cancer development by inducing DNA damage, promoting cell proliferation, and causing chronic inflammation. We compared expression of immunologic and inflammatory genes using a NanoString assay on archived prostate tumors from WTC Health Program (WTCHP) patients and non-WTC patients with prostate cancer. Furthermore, to assess immediate and delayed responses of prostate tissue to acute WTC dust exposure via intratracheal inhalation, we performed RNA-seq on the prostate of normal rats that were exposed to moderate to high doses of WTC dust. WTC prostate cancer cases showed significant upregulation of genes involved in DNA damage and G₂-M arrest. Cell-type enrichment analysis showed that Th17 cells, a subset of proinflammatory Th cells, were specifically upregulated in WTC patients. In rats exposed to WTC dust, we observed upregulation of gene transcripts of cell types involved in both adaptive immune response (dendritic cells and B cells) and inflammatory response (Th17 cells) in the prostate. Unexpectedly, genes in the cholesterol biosynthesis pathway were also significantly upregulated 30 days after acute dust exposure. Our results suggest that respiratory exposure to WTC dust can induce inflammatory and immune responses in prostate tissue. IMPLICATIONS: WTC-related prostate cancer displayed a distinct gene expression pattern that could be the result of exposure to specific carcinogens. Our data warrant further epidemiologic and cellular mechanistic studies to better understand the consequences of WTC dust exposure.Visual Overview: http://mcr.aacrjournals.org/content/molcanres/17/8/1605/F1.large.jpg.

SUN-417 Recovery Of Central Adrenal Insufficiency In A Patient With Hypophysitis Secondary To Immune Checkpoint Inhibitors Therapy

Hypophysitis is a well-recognized immune-related adverse event that occurs in approximately 16% of patients treated with immune checkpoint inhibitors (ICIs), particularly the anti-cytotoxic T-lymphocyte associated antigen (CTLA4) monoclonal antibody, ipilimumab. While the synthesis and secretion of some anterior pituitary hormones may recover, central adrenal insufficiency is thought to be permanent. A 26-year old male with metastatic renal cell carcinoma was started on treatment with the anti-programmed cell death 1 (PD-1) monoclonal antibody nivolumab. His pre-treatment TSH was 3.27 (0.34-5.60 µIU/mL). Six weeks after his first dose of nivolumab he developed biochemical hyperthyroidism: TSH 0.04µIU/mL, FT4 2.1 (0.80-1.50 ng/dL), without symptoms. He continued treatment with nivolumab, and 11 weeks after the first dose he remained hyperthyroid (TSH undetectable, FT4 2.65 (0.80-1.50 ng/dL)). He was then started on ipilimumab in addition to nivolumab for 4 cycles. A baseline random serum cortisol drawn at 1:30pm was 15.0 (6.7 - 22.6 µg/dL). Five weeks after starting combined ICI therapy he developed sudden onset of severe fatigue, and reported feeling unable to get out of bed. Random serum cortisol was 2.0µg/dL at 1pm, and further pituitary hormone evaluation was performed: ACTH 16 (7.2-63.3 pg/mL), prolactin 47.2 (2.6-13.1ng/mL), LH 3.47 (1.2-8.6 mIU/mL), FSH 14.6 (1.3-19.3 mIU/mL), TSH 1.91, FT4 0.85, testosterone 545.46 (300-1080ng/dL). Thyroid autoantibodies (anti-TPO, thyroglobulin, TSH receptor) were normal. A diagnosis of hypophysitis was made, and he was immediately started on prednisone 1mg/kg. A brain MRI reported no pituitary abnormalities. 48 hours after starting prednisone his symptoms resolved. He remained on prednisone 20mg daily for 4 weeks, and continued treatment with the ICI’s. His pituitary labs were repeated (3pm) - ACTH 5, cortisol 4.0, TSH 1.6, FT4 0.99, Testosterone 119, LH 3.63, FSH 18.4, IGF1 195 (155-432 ng/dL). His dose of prednisone was reduced to 5mg once daily. He continued to be monitored regularly by endocrinology with follow up testing of hormone levels. Four months after the initial presentation his testosterone level improved to 973.4, but his cortisol remained low. After five months his random serum cortisol (1pm) increased to 11.0, and testosterone was 901.5. The prednisone was cautiously discontinued with close monitoring for symptoms and hormone levels. He remained asymptomatic after discontinuation of prednisone, and after two months off glucocorticoid replacement his ACTH was 24.1 and cortisol was 13.0. This case demonstrates that central adrenal insufficiency can recover in patients who develop hypophysitis from ICI therapy. Close follow up and repeated measurement of pituitary hormones may identify more patients with hypothalamic-pituitary-adrenal axis recovery.

SAT-094 Overweight and Obesity Associated with Immune-Related Adverse Events in Patients on Immune Checkpoint Inhibitor Therapy

Background As immune checkpoint inhibitor (ICI) therapies (PD(L)1 and CTLA-4 inhibitors) are increasingly used for treating malignancy, immune-related adverse events (irAEs) are being encountered by clinicians more frequently. Obesity is a pro-inflammatory metabolic state that has been associated with a higher risk of developing autoimmune disease, but its role in irAEs in patients treated with ICIs is not well characterized. Hypothesis We hypothesized that patients on ICI therapy who were overweight or obese would be more likely to have a grade 2 or greater irAE compared to normal or underweight patients. Methods We retrospectively collected clinical data for 398 cancer patients with baseline body mass index (BMI) data who received ICIs between January 2011 and April 2017 at our institution. Patients were categorized as having lower BMI (low or normal weight, <25) or higher BMI (obese or overweight, ≥25). An irAE was defined as an AE during ICI therapy that was ≥ Grade 2 according to the Common Terminology Criteria for AEs. We compared patient demographic and clinical characteristics between BMI categories. To determine if BMI category was associated with irAEs, we used multivariate logistic regression. Demographics and variables significantly associated with irAEs were included in the model. Results 201 (50.5%) of patients had lower BMI and 197 (49.5%) had higher BMI. 98 patients (24.6%) had an irAE and median follow up time was 8.7 months. The most common malignancies were melanoma (19.6%), non-small cell lung cancer (23.7%), hepatocellular carcinoma (14.6%), and urothelial carcinoma (12.3%). Patients were treated with blockade of CTLA-4 (11.8%), PD1/PDL1, (77.9%), combination of CTLA-4 and PD(L)1 blockade concurrently (4.0%), and sequentially (6.3%). Patients with lower and higher BMI did not differ significantly in respect to age, gender, clinical stage, or category of ICI. Race differed significantly between high vs low BMI categories, (White 60.4% vs 47.3%, Black 8.1% vs 11.9%, Hispanic 11.7% vs 8%, Asian 3.6% vs 11.9%, Unknown/other 16.2% vs 20.9%, p<0.01). Patients with higher BMI were more likely to have a preexisting autoimmune disease (10.8% vs 7.5%, p=0.04). Higher BMI was significantly associated with irAEs (odds ratio (OR) 1.79, 95% confidence interval (CI) 1.09-2.96 in a model adjusted for age, gender, race, ICI category, and preexisting autoimmune disease. Other race (compared to white race) (OR 0.40, 95% CI 0.19-0.83, PD(L)1 blockade (compared to CTLA-4 blockade) (OR 0.49, 95% CI 0.24-0.99), and preexisting autoimmune disease (OR 2.8, 95% CI 1.4-5.7) were also significant predictors of irAEs in the adjusted model. Conclusions Being overweight or obese was associated with irAEs in patients on ICI therapy. Insights into how BMI mediates the immune effects of ICI therapy can potentially elucidate how inflammation plays a role in the metabolic sequelae of obesity and adiposity.

MON-603 Racial Distribution of Endocrine Complications in Oncology Patients Treated with Immune Checkpoint Inhibitors

Background: Immune-related adverse events (irAEs) have been frequently described with the growing use of immune checkpoint inhibitors (ICI) in cancer treatment. While many autoimmune diseases are known to be more prevalent in certain racial groups, it is unknown if there are racial disparities in the rate of irAEs. Clinical trials reporting irAEs thus far have not explored their distribution in underrepresented minorities. It is important to study irAEs in racially diverse populations to better understand which patients are more likely to be impacted. Hypothesis: We sought to describe the demographics of a diverse cohort of patients treated with ICIs, as well as the racial distribution of irAEs. We hypothesized that there would be a significant difference among self-reported races experiencing ICI-related endocrine diseases. Methods: IRB approval was obtained to identify 411 oncology patients who were treated with ICIs between January 2011 and April 2017 from an EMR-based data repository. We collected data on age, gender, BMI, comorbidities, and median follow up time, which were further stratified according to self-identified race (White, Black, Hispanic, Asian, Other/Unknown). Endocrine adverse events were recorded according to race and were defined as events that were ≥ Grade 2 according to the Common Terminology Criteria for Adverse Events. We used the Fisher exact test for categorical variables and the Kruskal-Wallis test for continuous variables in the comparative analyses. Results: Of 411 patients treated with ICIs, 53.3% were White, 10.2% were Black, 10.5% were Hispanic, 7.5% were Asian, and 18.5% were Other/Unknown. The mean age was 65.3 years (67.8 in Whites, 63.7 in Blacks, 62.2 in Hispanics, 60.5 in Asians, 62.8 in Other/Unknown; p=0.0012). 38.4% were Female and 61.6% were Male. Mean BMI was 25.9 kg/m². 10.9% of all patients had pre-existing autoimmune disease (White: 11.0%, Black: 9.5%, Hispanic: 11.6%, Asian: 0, Other/Unknown: 15.8%; p=0.164). 7.3% of all patients had pre-existing thyroid disease (White: 6.9%, Black: 7.1%, Hispanic: 7.0%, Asian: 0, Other/Unknown: 11.8%; p=0.311). Mean follow up period was 8.7 months. 54 (13.1%) patients experienced any endocrine adverse effect without a statistically significant difference among racial groups (White: 16.0%, Black: 16.7%, Hispanic: 11.6%, Asian: 6.5%, Other/Unknown: 6.6%; p=0.189). 14.8% developed hypophysitis, 70.4% developed thyroid disease, 13.0% developed adrenal insufficiency, and 1.9% developed diabetes. Conclusions: Self-reported race was not associated with the development of ICI-related endocrinopathies in a diverse group of oncology patients. Further studies are needed to continue to characterize the populations experiencing immune-related endocrine complications in ICI therapy.

Obesity and metastatic castration resistant prostate cancer: Results from the control arms of ASCENT2, MAINSAL and VENICE trials

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Background: Previous findings regarding the correlation between body mass index (BMI) and survival in patients with prostate cancer are conflicting and may be disease-state dependent. We aimed to test whether BMI among patients with metastatic prostate cancer (mCRPC) is associated with overall survival (OS) and cancer-specific mortality (CSM). Methods: We identified 1577 patients with mCRPC from the control arms of 3 randomized trials. The role of BMI was investigated both as a continuous and categorical variable ( < 20 vs. 20-25 vs. 25-30 vs. > 30 km/m2). A BMI > 30 kg/m2 was considered obese. Analyses were adjusted for age, PSA, ECOG, # of metastasis and prior treatment. A Cox semi-proportional hazard model was used to predict OS, whereas the competing risks regression was used for predicting cancer-specific mortality (CSM). Results: The median (IQR) age for the patient population was 69 (63,74) years with a median (IQR) BMI of 28 (25-31) kg/m2. Of the 1577 patients included, 655 had died during follow-up (median follow-up for survivors = 12 months). BMI emerged as a protective factor for OS both as a continuous variable (HR: 0.96; 95% CI: 0.94, 0.99; p = 0.015) and as a categorical variable (obesity: HR: 0.71, 95% CI: 0.53, 0.96; p = 0.027). The effect BMI on CSM was confirmed both as a continuous (SHR: 0.94; 95% CI: 0.91, 0.98; p = 0.002) and as a categorical variable (obesity SHR: 0.65; 95% CI: 0.45, 0.93; p = 0.018). No interaction was detected between the BMI categories and docetaxel dose. Conclusions: Obesity, compared with lower weight categories, is associated with improved CSM and OS in mCRPC treated with docetaxel. The mechanistic basis for this observation warrants further study.

The impact of pathologic downstaging with neoadjuvant chemotherapy on survival of patients with muscle-invasive bladder cancer

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Background: Achieving a pathologic complete response (pCR) with neoadjuvat chemotherapy (NAC) in patients with muscle-invasive bladder cancer (MIBC) has been correlated with improved survival. Such findings have served as justification for using pCR as an intermediate endpoint for clinical trials and perpetuated the notion that NAC only benefits patients achieving a pCR. The impact of downstaging (pDS) on outcomes of patients with MIBC treated with NAC has been underexplored. Methods: The National Cancer Database (NCDB) was queried to identify patients with MIBC (cT2-4N0M) treated with platinum-based NAC. A multivariable Cox model including either pDS or pCR and adjusted for potential confounders was generated and c-indices were computed to evaluate whether the inclusion of pDS or pCR was more informative in predicting overall survival (OS). Results: Overall 2,010 patients from NCDB met inclusion criteria. The median follow-up for survivors was 36 months with a 5-year OS of 47% (95% CI 44, 50%). Overall, 694 (43.5%) patients achieved pDS; 139, 201, 291, 49 and 14 downstaged of 1, 2, 3, 4 and 5 categories, respectively. The 5-year OS rate for patients who achieved pDS was 70%. A pCR was achieved by 306 (15%) of the patients, the 5-year OS rate in this group was 84%. In the NCDB, pDS and pCR emerged as predictors of OS: HR:0.36 (95% CI: 0.30,0.44, p<0.001) and 0.25 (95% CI: 0.18,0.25, p<0.001), respectively. The cindex of the model including pDS was 72 vs. 70 of the model with pCR. Conclusions: pDS represents a more informative endpoint in predicting OS with respect to pCR in patients receiving NAC for MIBC.

Abstract B157: Modulation of natural killer cell dysfunction in human bladder cancer

T-cells undergo a progressive program of dysfunction termed “exhaustion” during chronic inflammatory pathologies such as cancer. T-cell exhaustion is characterized by diminished effector functionality and inefficient tumor immunosurveillance. However, it is unknown whether an analogous program undermines the contribution of innate lymphocytes like natural killer cells (NK) to tumor-surveillance, and what phenotype might define it. Therefore, we examined expression of inhibitory receptors and the corresponding functional potential of NK and T-cells present in peripheral blood mononuclear cells (PBMC) and tumor tissue of 59 individuals representative of the clinical spectrum of human bladder cancer (BC). PBMC and cell suspensions from freshly dissociated primary tumors were analyzed by flow cytometry to measure changes in the expression of the inhibitory receptors Tim-3, TIGIT, and PD-1, and to determine the composition of hematopoietic lineages in each tissue. NK effector function was assessed via activation with IL-2 or IL-15, followed by co-culture with Class I HLA-deficient targeT-cells to measure cytokine production and degranulation. Additionally, we determined the effect on NK cell function of ex vivo blockade of Tim-3 and TIGIT by the addition of monoclonal antibodies prior to functional assays. We found that NK cells significantly up-regulate expression of Tim-3 and TIGIT, but not PD-1, in both the PBMC and tumors of BC patients. T-cells demonstrate a similar pattern of expression. but with a far lower frequency of positive cells. The magnitude of Tim-3 expression by NK cells is a barometer of tumor invasiveness on cells in both PBMC and tumor tissue, while TIGIT is induced equivalently in BC patients independently of tumor stage. Importantly, both molecules are expressed at similar frequencies on NK cells isolated from blood or tumor, independent of the magnitude of overall expression, yet define NK with different functional potential. NK cells in PBMC from BC patients are functionally comparable to NK cells from healthy donors in their ability to produce IFNγ/TNFα and degranulate in response to targeT-cells, while tumor NK are refractory to both stimuli. NK cells from tumor tissue are not terminally exhausted as effector functions are restored after “resting” ex vivo prior to stimulation. Ex vivo blockade of Tim-3, but not TIGIT, enhances effector function in peripheral NK and T-cells from BC patients, but is ineffective for NK cells in tumor tissue, implicating suppressive factors specific to tumor in mediating NK dysfunction. Tim-3 blockade was most efficient in peripheral NK cells from BC patients that were activated with IL-15 versus IL-2, suggesting that local cytokine milieu can affect responsiveness to subsequent checkpoint inhibition. Overall, our data suggest that both NK and T-cells from patients with BC are enriched for expression of the shared inhibitory receptors Tim-3 and TIGIT, and that expression in the peripheral blood mirrors expression in the tumor. However, tissue-specific cues present in bladder tumors, but not in the periphery, ultimately confer effector dysfunction. Furthermore, because blockade of Tim-3 enhances IFNγ and TNFα production by NK cells present in the peripheral blood of BC patients, it may represent a new strategy to modulate innate, antitumor immunity while simultaneously conferring benefit in the adaptive compartment.

Citation Format: Adam M. Farkas, Francois Audenet, Harry Anastos, Matthew Galsky, John P. Sfakianos, Nina Bhardwaj. Modulation of natural killer cell dysfunction in human bladder cancer [abstract]. In: Proceedings of the Fourth CRI-CIMT-EATI-AACR International Cancer Immunotherapy Conference: Translating Science into Survival; Sept 30-Oct 3, 2018; New York, NY. Philadelphia (PA): AACR; Cancer Immunol Res 2019;7(2 Suppl):Abstract nr B157.

Promoting patient engagement in bladder cancer (BC) care through education

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Background: BC is the 6th leading cause of cancer in the US and it is estimated that 81,190 Americans will be diagnosed this year. Promoting patient knowledge and involvement in BC care have led to successful management strategies. We offered 1 hour of online education to patients and their caregivers to provide clinical and supportive information that lends a sense of control, supports effective self-management, and promotes patient-physician communication. Methods: PlatformQ Health Education, in partnership with the Bladder Cancer Advocacy Network, developed and executed an interactive education program for patients with BC and their caregivers, which was broadcast live online on cancercoachlive.com on September 29, 2017 and on-demand through March 29, 2018. The program was viewed on cancercoachlive.com by 587 learners and attracted 533 additional learners through social media channels (e.g. Facebook). Education focused on treatment options and the accessibility of resources and support. Self-reported surveys, distributed to patients and caregivers 8 weeks after the program, were analyzed for improvements in perceived engagement in their cancer care. Results: After participating in the education, a majority of the learners reported they felt knowledgeable on treatment options to discuss with their HCPs (92%, n = 60) and resources and information they can use for self-care strategies (88%, n = 58). Follow-up survey results (n = 60) also indicated that the education helped 50% of learners enhance their communication with their HCP. Moreover, 54% of learners (n = 48) felt more in control of health care decisions, and 36% of learners (n = 59) reported improvements in their health-related behaviors. Write-in examples focused on staying informed of treatments and side effects, seeking support, and proactively asking questions to their HCPs. Conclusions: As ASCO guidelines note, providing patients with preoperative information and encouraging them to take an active part in the decision-making process are essential elements to achieving positive outcomes in BC. Results from the patient survey indicate that participating in an interactive, online education program enhanced knowledge and promoted patient engagement in BC care.

Tim-3 and TIGIT mark Natural Killer cells susceptible to effector dysfunction in human bladder cancer

Natural Killer cell (NK) effector functions are diminished during cancer but the phenotype and mediators of this process are unclear. In contrast, dysfunctional T cells express markers of “exhaustion” (e.g. CTLA-4 and PD-1), and inhibition of signaling through these molecules has improved clinical outcome in multiple tumors. Our data from 100+ patients with bladder cancer (BC) suggests that NK undergo an analogous process of exhaustion marked by up-regulation of Tim-3 and TIGIT in both the periphery and tumor. Tim-3 and TIGIT are induced on both immature and mature NK subsets suggesting implications for normal NK maturation. The magnitude of Tim-3 expression in both tissues is tuned to the invasiveness of the primary tumor, while TIGIT is not, making Tim-3 function as a rheostat for primary tumor invasiveness. Both molecules are expressed at equivalent frequencies in both tissues independent of the magnitude of overall expression but define NK with different effector functions. Peripheral NK from BC patients are functionally comparable to NK from healthy donors in their ability to produce IFNγ and degranulate in response to target cells, while tumor NK are refractory to both stimuli. NK from tumors are not terminally exhausted as they make IFNγ, TNFa, and degranulate after “resting” ex vivo prior to stimulation. Blockade of Tim-3, but not TIGIT, enhances effector function in peripheral NK from BC patients, but is ineffective for NK in tumor tissue implicating tumor-specific factors in mediating NK dysfunction. Tim-3 blockade was most efficient in NK from BC patients after activation with IL-15 suggesting specific inflammatory cues affect responsiveness to checkpoint blockade. Ongoing work will develop strategies to reverse NK exhaustion.

Impact of number of cycles of platinum-based first-line chemotherapy for advanced urothelial carcinoma

426

Background: 6 cycles of platinum-based chemotherapy (CT) are conventionally targeted to treat locally advanced unresectable or metastatic urothelial carcinoma (UC). However, cisplatin is associated with significant cumulative toxicities, which render it challenging to deliver 6 cycles. Since this issue has not been investigated prospectively, we conducted a retrospective analysis. Methods: The Retrospective International Study of Invasive/Advanced Cancer of the Urothelium (RISC) database was used to conduct a retrospective analysis. The association of the number of cycles of platinum-based first-line CT with overall survival (OS) was investigated by a Cox regression utilizing multivariate analysis after controlling for previously recognized prognostic factors used in a nomogram ( Eur Urol, 2017). The primary analysis was a comparison of < 6 cycles vs. ≥6 cycles. Six-month landmark analysis was applied throughout, accounting for OS events. Additionally, we excluded patients (pts) receiving < 3 or > 9 cycles to reduce confounding due to early removal for toxicities, progression and patient decision and increased number of cycles due to response and pt-related factors. Results: Of 1020 pts available from RISC, 472 (cisplatin = 338, carboplatin = 134) were evaluable for the landmark analysis with 281 events. A total of 157 pts received 3-5 cycles (median 4) and 315 received 6-9 cycles (median 6). There was no significant difference between 3-5 vs. 6-9 cycles of platinum-based chemotherapy (HR 1.02, 95%CI: 0.77-1.33, p = 0.91). No significant interactions were observed with type of platinum (p = 0.09) and “completed planned CT” (p = 0.56). Comparison of 4 vs. 6 cycles (p = 0.57) and < 6 vs 6 vs 7-9 (p = 0.9) also yielded no significant differences for association with OS. No differential association was observed with survival for 3-5 vs. 6-9 cycles when examining by nomogram-defined risk group tertiles. Limitations of a hypothesis-generating retrospective analysis apply. Conclusions: 4 cycles of platinum based first-line CT appear adequate to treat advanced UC. The omission of excessive cycles will avoid unnecessary toxicities and facilitate better transition to second-line and switch maintenance therapy.

Abstract 4262: Inflammatory gene expression differences among prostate cancer patients exposed to the World Trade Center aftermath

Background: World Trade Center (WTC) rescue and recovery workers were exposed to a complex mixture of dust and debris after the collapse of the WTC towers. An excess incidence of prostate cancer was observed in the WTC workers and, more advanced prostate cancer cases have been associated with higher levels of WTC exposure. As inflammation is known to promote tumor development and progression and the prostate cancer etiology remains uncertain, we compared RNA expression of inflammatory markers in prostate cancer tumors from WTC patients with matched prostate cancer patients not related to WTC.

Methods: RNA was prepared from formalin-fixed paraffin embedded tumors of 15 WTC prostate cancer and 14 non-WTC prostate cancers, age, race, and Gleason-score matched. Gene expression was quantified using Nanostring nCounter® PanCancer Immune Profiling Panel, which combines markers for 24 immune cell types and populations, 30 common cancer antigens and genes representing all immune response categories including key checkpoint blockade genes. Data analysis was performed using the NanoString nSolver 2.6 analysis software. Genes shown to be characteristic of innate and adaptive immune cell populations were used to derive cell-type scores indicating population abundance of each immune cell type. Comparisons of cell type scores were performed using Student’s t test.

Results: WTC prostate cancers expressed high levels of genes associated with chronic inflammation: NFATC2 (Fold change=3.0, P&lt;0.001), MRC1 (Fold change=2.0, P=0.001), CT8L (Fold change=1.5, P=0.01), CSF1 (Fold change=1.5, P=0.001), NFKB1 (Fold change=1.3, P=0.005), CXCL13 (Fold change=3.7, P=0.04), IL6 (Fold change=2.5, P=0.04) and ITCH (Fold change= 0.3, P=0.001) compared with non-WTC prostate cancers. Conversely, non-WTC prostate cancers expressed higher levels of genes associated with innate immunity: TIRAP (Fold Change=0.05, P&lt;0.001), IRF3 (Fold change=1, P&lt;0.001), and FADD (Fold change=0.5, P=0.005), compared with WTC prostate cancer. In cell type enrichment analysis, macrophage and CD45+ cells scored higher in non-WTC (8.83±0.75 SD and 9.09±0.78 SD) than WTC (7.81±0.73 SD and 8.53±0.53 SD) prostate cancer samples (t=3.70, P&lt;0.001 and t=2.29, P=0.02); regulatory T cells scored higher in WTC (5.90±0.52 SD) than non-WTC (5.42±0.67 SD) prostate cancer samples (t=2.15, P=0.04).

Conclusions: Compared to non-WTC prostate cancers, tumors from WTC-exposed patients show overall lower expressions of genes involved in local innate immune-system response and a higher expression of adaptive immune-system response genes. Environmental factors, such as exposure during the 9/11 aftermath, may have played a role in the development of advanced prostate cancer in these patients via high immune-tolerance. The results have implications for a role of environmental factors in prostate carcinogenesis.

Citation Format: Dana Hashim, Yixuan Gong, Matthew Galsky, Charles Baker, Paolo Boffetta, Michael J. Donovan, Emanuela Taioli, William K. Oh. Inflammatory gene expression differences among prostate cancer patients exposed to the World Trade Center aftermath [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 4262. doi:10.1158/1538-7445.AM2017-4262

A phase I study of the safety and immunogenicity of a multipeptide personalized genomic vaccine in the adjuvant treatment of solid cancers

TPS3114

Background: Mutation-derived tumor antigens (MTAs) arise as a direct result of somatic variations, including nucleotide substitutions, insertions, and deletions that occur during carcinogenesis. These somatic variations can be characterized via genetic sequencing and used to identify MTAs. We propose a platform for a fully-personalized MTA-based vaccine in the adjuvant treatment of solid tumors. Methods: This clinical trial is a single-arm, open label, proof-of-concept phase I study designed to test the safety and immunogenicity of the Personalized Genomic Vaccine 001 (PGV001). The single-center study will enroll 20 eligible subjects with histological diagnosis of the following tumor types: (a) head and neck squamous cell cancer, (b) non-small cell lung cancer, (c) ductal or lobular breast cancer, (d) serous carcinoma of the ovary, uterine adnexa, (e) urothelial carcinoma of renal pelvis or bladder, (f) cutaneous squamous cell cancer. Subjects must have no measurable disease at time of first vaccine administration, and 5-year disease recurrence risk of > 30%. Patients will receive 10 doses of PGV001 as well as 10 doses of poly-ICLC (toll-like receptor-3 agonist, vaccine adjuvant), administered 1 day after PGV001 vaccination. Toxicity (endpoint 1) will be defined by Common Terminology Criteria for Adverse Events v5.0. Blood samples will be collected at various time points for immune response monitoring of MTA-specific humoral and cellular immune responses. For each patient, immunogenicity (endpoint 2) will be defined as an epitope-specific T cell response, detectable in peripheral blood samples after PGV001 vaccination. The change in the frequency of vaccine-induced epitope-specific T lymphocyte populations post-vaccination relative to baseline will be determined using mixed effects linear regression modeling. Conclusions: Our clinical trial will test for the first time the safety and immunogenicity of PGV001 in patients with multiple solid cancers. The information learned from this clinical trial will instruct the next generation of MTA-based vaccines, future development of immunotherapeutic approaches and rational combinations. Clinical trial information: NCT02721043.

Therapy for chemopretreated metastatic urothelial cancer (mUC) with the antibody-drug conjugate (ADC) sacituzumab govitecan (IMMU-132)

327

Background: Patients (pts) with mUC pre-treated with platinum-containing chemotherapy have limited therapeutic options, with checkpoint-inhibitor immunotherapy (IO) responses in a minority of pts. We present an interim update of the safety and activity of sacituzumab govitecan (IMMU-132), an anti-Trop-2-SN-38 ADC, as therapy for chemotherapy-pretreated mUC pts (ClinicalTrials.gov, NCT01631552). Methods: We enrolled 32 pts with mUC and ECOG PS 0-1 who failed ≥ 1 prior standard therapy (median=3; range, 1-5). IMMU-132 was administered at 8 or 10 mg/kg on days 1 and 8 every 21 days, continued until disease progression (PD) or unacceptable toxicity. Response-evaluable pts received ≥ 2 doses, and had ≥ 1 post-baseline response assessment. Results: Twenty-five pts [median age 68 yrs (range: 50-91), 24 males] are currently assessable for safety and response; 23 had prior platinum-containing therapy; 46% had >2 prior therapies; 4 also had IO agents. Sites of metastases included liver (N=4; 16%), lungs (N=7; 28%), bone (N=4; 16%), and lymph nodes (N=16; 64%). Pts received a median of 7 cycles (range, 2-23) of IMMU-132. ORR was 36% (9/25) [1 complete (CR) and 8 partial responses (PR)]; 44% (11/25) had stable disease (SD). Further, pts with 1 line of prior chemotherapy had an ORR of 53.8% (7/13), and 16.7% for those with 2 to 5 prior therapy lines. Median PFS for all patients is 7.2 mos (95% CI, 4.9-10.7); median survival is not reached yet. Of the 4 pts with progression after prior IO, there were 1 PR and 2 SDs with IMMU-132. Duration of response for CR/PR pts is currently 5.1 mos (95% CI, 4.1-12.9) and 10/11 pts (5 with ≥ 20% tumor reduction) had stable disease > 4 mos. Grade 4 neutropenia (16%) lasted < 7 days, and non-hematological grade 3 AEs included fatigue (12%) and hypophosphatemia (8%). No treatment-related deaths were observed. Analysis of Trop-2 expression revealed 1+ to 3+ positive staining in 95% of 19 archival patient specimens. Conclusions: With an ORR of 36% and a median PFS of 7.2 months in a heavily pretreated population, these interim results suggest that IMMU-132 is a promising agent as 2nd line or later therapy for platinum- or IO- pretreated mUC pts. Clinical trial information: NCT01631552.

Protein Profiling of Bladder Urothelial Cell Carcinoma

This study aimed to detect protein changes that can assist to understand the underlying biology of bladder cancer. The data showed forty five proteins were found to be differentially expressed comparing tumors vs non-tumor tissues, of which EGFR and cdc2p34 were correlated with muscle invasion and histological grade. Ten proteins (ß-catenin, HSP70, autotaxin, Notch4, PSTPIP1, DPYD, ODC, cyclinB1, calretinin and EPO) were able to classify muscle invasive BCa (MIBC) into 2 distinct groups, with group 2 associated with poorer survival. Finally, 3 proteins (P2X7, cdc25B and TFIIH p89) were independent factors for favorable overall survival.

Abstract 3435: Prostate cancer in WTC respondents

Background: Ten years following the 9/11/2001 attacks on the World Trade Center (WTC), an increased incidence of prostate cancer was reported in two separate cohorts of WTC rescue and recovery workers. Whether this increase is due to WTC-related exposures or increased surveillance is uncertain.

Methods: Prostate cancer cases and Gleason scores diagnosed after 9/11 from 2002 to 2014 were obtained from the WTC Health Program (n = 180). Differences in proportions of Gleason scores 7+ (moderate to high-grade cancer) in WTC respondents and New York State were calculated based on the NYS Cancer Registry (NYSCR). An age-adjusted rate for Gleason scores of ≥7 was calculated using the indirect method based on NYSCR. Age- and race-matched prostate cancer non-WTC respondent controls (n = 253) were obtained from Mount Sinai Hospital. We evaluated the effects of WTC-respondent status, exposure level, age, race, prostate-specific antigen (PSA) concentrations, and clinical stage on Gleason scores using log-linear regression. WTC exposure was analyzed by four categorical levels and continuously using a relative rank of potential carcinogen-related post-9/11 exposures. Differences in mean numbers of PSA screening visits were assessed using Student's t-test.

Results: The age-adjusted rate for a Gleason score ≥7 was 1.15 for WTC respondents (95% Confidence Interval (CI): 0.94, 1.36) compared to the NYSCR. WTC respondents &lt; 40 years old had an 8-time higher proportion of aggressive cancers than expected based on NYSCR age-specific rates. The proportion of Gleason scores ≥7 was 0.33 (95% CI: -0.06, 0.12) higher in WTC respondents than NYSCR. WTC respondents had lower Gleason scores (Odds Ratio (OR): 0.90 (95% CI: 0.82, 0.99)), PSA values (OR: 0.79; 95% CI: 0.71, 0.89), but higher clinical stage (OR: 1.04; 95% CI: 0.92, 1.16) than controls. When Gleason score was adjusted for PSA and clinical stage, the OR for PSA testing was 1.04; 95% CI: 0.88, 1.23 and clinical stage was lower (OR: 0.82; 95% CI: 0.69, 0.98) in WTC-respondent cases. The mean numbers of PSA-screening visits were not different between WTC respondents and controls (t = 0.64; P = 0.52) and were not associated with Gleason scores ≥7 (OR: 1.0; 95% CI: 0.88, 1.13). Four-level exposure categories (OR: 0.99; 95% CI: 0.99, 1.00) and continuous rank (OR: 0.88; 95% CI: 0.73, 1.06) showed no associations with Gleason scores. Days spent at WTC (OR: 1.00; 95% CI: 1.00, 1.03) and working on the WTC debris pile (OR: 0.95; 95% CI: 0.86, 1.05) showed similar results.

Conclusions: Young WTC respondents had higher Gleason scores than the NYSCR. Number of PSA screening visits did not significantly differ between WTC respondents and controls and PSA values of WTC respondents were lower than controls. Aggressive prostate cancer was not associated with WTC exposure levels. Considering the high grade of prostate cancer in younger men and the long latency for prostate cancer development, continued monitoring is needed to determine alternative causes of elevated prostate cancer in the WTC population.

Citation Format: Dana Hashim, Paolo Boffetta, William Oh, Sylvain Wallenstein, Matthew Galsky, Emanuela Taioli. Prostate cancer in WTC respondents. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 3435.

Collaborating to Move Research Forward: Proceedings of the 10th Annual Bladder Cancer Think Tank

The 10th Annual Bladder Cancer Think Tank was hosted by the Bladder Cancer Advocacy Network and brought together a multidisciplinary group of clinicians, researchers, representatives and Industry to advance bladder cancer research efforts. Think Tank expert panels, group discussions, and networking opportunities helped generate ideas and strengthen collaborations between researchers and physicians across disciplines and between institutions. Interactive panel discussions addressed a variety of timely issues: 1) data sharing, privacy and social media; 2) improving patient navigation through therapy; 3) promising developments in immunotherapy; 4) and moving bladder cancer research from bench to bedside. Lastly, early career researchers presented their bladder cancer studies and had opportunities to network with leading experts.

Abstract C132: Therapeutic reactivation of PP2A for prostate cancer treatment

Several new therapies have recently been approved for patients with castration-resistant prostate cancer (CRPC), however, none are curative and tumors ultimately develop resistance. Advances in the treatment of CRPC require novel approaches and therapies such as those outlined in this study. Most drug development efforts have focused on targeting single oncogenic proteins, an approach limited by the complexity of signaling networks and associated cross talk. Targeting phosphatases, the key negative regulators of signaling proteins, on the other hand, may overcome some of these limitations, particularly if these negative regulators themselves are altered.Through reverse engineering of tricyclic neuroleptic drugs, we have developed a series of small molecule activators of the serine/threonine phosphatase 2A (PP2A), a key negative regulator of numerous oncogenic signaling pathways. PP2A acts as a tumor suppressor and dephosphorylates several critical nodes in prostate cancer pathogenesis including the androgen receptor (AR). Decreased PP2A expression and/or activity have been correlated with castration-resistance in cell culture and human prostate cancer studies. These small molecule activators of PP2A (SMAPs), as represented by TRC-794, TRC-1154, and DT-061, directly bind and activate PP2A and have favorable pharmaceutical properties. In this study we sought to determine the activity of SMAPs in clinically relevant preclinical models of prostate cancer.

Treatment of prostate cancer cell lines with SMAPs resulted in decreased cell viability and colony formation, cell cycle arrest, and an increase in apoptosis. Global Phosphoproteomic analysis of TRC-794 treated prostate cancer cells revealed that the AR and MYC were significantly perturbed in drug treated cells compared to controls which was subsequently confirmed by western blotting. Western blot analysis of prostate cancer cells demonstrated dose-dependent degradation of the AR resulting in PSA reduction and changes in canonical AR target gene expression. In order to investigate whether PP2A was mediating SMAP induced AR degradation, LNCAP cells were stably transduced with the SV40 small t antigen (ST), a potent oncoprotein that perturbs PP2A function. SMAPs were unable to degrade AR in LNCAP cells transduced with ST, suggesting that PP2A mediates SMAP induced AR degradation.

SMAPs were evaluated in vivo in xenograft models representing prostate cancers that are sensitive to conventional therapy and resistant to enzalutamide, the current gold standard, due to overexpression of the AR or expression of androgen receptor splice variants (AR-SV). Single agent treatment with DT-1154 or DT-061 in vivo resulted in either significant tumor growth inhibition or tumor regression and induction of tumor cell apoptosis comparable to enzalutamide. Western blot analysis of the tumors demonstrated that the effects on tumor volume correlated strongly with target engagement as evidenced by significant decreases in PSA and AR expression in vivo. Additionally, these compounds demonstrated favorable pharmacokinetics and showed no overt toxicity. Combined these data highlight the potential for PP2A activation for both the treatment of CRPC and potentially for diverse PP2A inactivated tumor types and diseases.

Citation Format: Kim McClinch, Rita Avelar, David Callejas, David Kastrinsky, Michael Ohlmeyer, Stephen Plymate, Matthew Galsky, Goutham Narla. Therapeutic reactivation of PP2A for prostate cancer treatment. [abstract]. In: Proceedings of the AACR-NCI-EORTC International Conference: Molecular Targets and Cancer Therapeutics; 2015 Nov 5-9; Boston, MA. Philadelphia (PA): AACR; Mol Cancer Ther 2015;14(12 Suppl 2):Abstract nr C132.

Generation of Prostate Cancer Patient Derived Xenograft Models from Circulating Tumor Cells

Patient derived xenograft (PDX) models are gaining popularity in cancer research and are used for preclinical drug evaluation, biomarker identification, biologic studies, and personalized medicine strategies. Circulating tumor cells (CTC) play a critical role in tumor metastasis and have been isolated from patients with several tumor types. Recently, CTCs have been used to generate PDX experimental models of breast and prostate cancer. This manuscript details the method for the generation of prostate cancer PDX models from CTCs developed by our group. Advantages of this method over conventional PDX models include independence from surgical sample collection and generating experimental models at various disease stages. Density gradient centrifugation followed by red blood cell lysis and flow cytometry depletion of CD45 positive mononuclear cells is used to enrich CTCs from peripheral blood samples collected from patients with metastatic disease. The CTCs are then injected into immunocompromised mice; subsequently generated xenografts can be used for functional studies or harvested for molecular characterization. The primary limitation of this method is the negative selection method used for CTC enrichment. Despite this limitation, the generation of PDX models from CTCs provides a novel experimental model to be applied to prostate cancer research.

A robust blood gene expression-based prognostic model for castration-resistant prostate cancer

BACKGROUND

Castration-resistant prostate cancer (CRPC) is associated with wide variations in survival. Recent studies of whole blood mRNA expression-based biomarkers strongly predicted survival but the genes used in these biomarker models were non-overlapping and their relationship was unknown. We developed a biomarker model for CRPC that is robust, but also captures underlying biological processes that drive prostate cancer lethality.

METHODS

Using three independent cohorts of CRPC patients, we developed an integrative genomic approach for understanding the biological processes underlying genes associated with cancer progression, constructed a novel four-gene model that captured these changes, and compared the performance of the new model with existing gene models and other clinical parameters.

RESULTS

Our analysis revealed striking patterns of myeloid- and lymphoid-specific distribution of genes that were differentially expressed in whole blood mRNA profiles: up-regulated genes in patients with worse survival were overexpressed in myeloid cells, whereas down-regulated genes were noted in lymphocytes. A resulting novel four-gene model showed significant prognostic power independent of known clinical predictors in two independent datasets totaling 90 patients with CRPC, and was superior to the two existing gene models.

CONCLUSIONS

Whole blood mRNA profiling provides clinically relevant information in patients with CRPC. Integrative genomic analysis revealed patterns of differential mRNA expression with changes in gene expression in immune cell components which robustly predicted the survival of CRPC patients. The next step would be validation in a cohort of suitable size to quantify the prognostic improvement by the gene score upon the standard set of clinical parameters.