Phase 2 trial of tremelimumab in patients with metastatic urothelial cancer previously treated with programmed death 1/programmed death ligand 1 blockade

INTRODUCTION

Programmed death 1 (PD-1)/programmed death ligand 1 (PD-L1) blockade has changed the landscape of treatment for metastatic urothelial cancer, but single-agent cytotoxic T-lymphocyte-associated protein 4 (CTLA-4) blockade in metastatic urothelial cancer has been underexplored. A prior phase 2 trial of tremelimumab in PD-1/PD-L1-blockade naive patients with metastatic urothelial cancer revealed activity comparable to that observed with PD-1/PD-L1 blockade raising the hypothesis that these classes of immune checkpoint inhibitors might be non-cross-resistant.

METHODS

The current phase 2 trial treated patients with PD-1/PD-L1 blockade-resistant metastatic urothelial cancer with single-agent tremelimumab (750 mg intravenously every 28 days for up to 7 cycles). The primary end point was objective response rate.

RESULTS

Twenty-six patients were enrolled and 24 patients were evaluable for response. The objective response rate was 8.3%, composed of a total of two partial responses that lasted 10.9 and 24.0 months. Stable disease was observed in another 20.8% of patients, with a median duration of stable disease of 5.4 months. Diarrhea occurred in 15 patients (58%), elevated hepatic transaminases occurred in seven patients (27%), and adrenal insufficiency occurred in two patients (8%); one patient died after experiencing immune-related hepatitis.

CONCLUSIONS

High dose CTLA-4 blockade in patients with PD-1/PD-L1-resistant metastatic urothelial cancer has modest activity and is associated with treatment-related toxicity similar to prior reports.

Detection of Testicular Metastasis from Renal Cell Carcinoma on PSMA-PET Scan

The use of prostate-specific membrane antigen-positron emission tomography (PSMA-PET) is becoming more widespread for the diagnosis and management of prostate cancer. Here we report a case of oligometastatic renal cell carcinoma (RCC) to the testes diagnosed incidentally on PSMA-PET imaging. This case demonstrates the potential for diagnosis of nonprostate disease with PSMA-PET imaging, as well as the promising nature of PSMA-PET for the diagnosis and surveillance of RCC. In addition, this case report discusses the rare occurrence of oligometastatic RCC to the testis.

Spatial Relationships in the Tumor Microenvironment Demonstrate Association with Pathologic Response to Neoadjuvant Chemoimmunotherapy in Muscle-invasive Bladder Cancer

BACKGROUND

Platinum-based neoadjuvant chemotherapy (NAC) is standard for patients with muscle-invasive bladder cancer (MIBC). Pathologic response (complete: ypT0N0 and partial:

OBJECTIVE

Using the NanoString GeoMx platform, we performed proteomic digital spatial profiling (DSP) on transurethral resections of bladder tumors from 18 responders (

DESIGN, SETTING, AND PARTICIPANTS

Pretreatment tumor samples were stained by hematoxylin and eosin and immunofluorescence (panCK and CD45) to select four regions of interest (ROIs): tumor enriched (TE), immune enriched (IE), tumor/immune interface (tumor interface = TX and immune interface = IX).

OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS

DSP was performed with 52 protein markers from immune cell profiling, immunotherapy drug target, immune activation status, immune cell typing, and pan-tumor panels.

RESULTS AND LIMITATIONS

Protein marker expression patterns were analyzed to determine their association with pathologic response, incorporating or agnostic of their ROI designation (TE/IE/TX/IX). Overall, DSP-based marker expression showed high intratumoral heterogeneity; however, response was associated with markers including PD-L1 (ROI agnostic), Ki-67 (ROI agnostic, TE, IE, and TX), HLA-DR (TX), and HER2 (TE). An elastic net model of response with ROI-inclusive markers demonstrated better validation set performance (area under the curve [AUC] = 0.827) than an ROI-agnostic model (AUC = 0.432). A model including DSP, tumor mutational burden, and clinical data performed no better (AUC = 0.821) than the DSP-only model.

CONCLUSIONS

Despite high intratumoral heterogeneity of DSP-based marker expression, we observed associations between pathologic response and specific DSP-based markers in a spatially dependent context. Further exploration of tumor region-specific biomarkers may help predict response to neoadjuvant chemoimmunotherapy in MIBC.

PATIENT SUMMARY

In this study, we used the GeoMx platform to perform proteomic digital spatial profiling on transurethral resections of bladder tumors from 18 responders and 18 nonresponders from two studies of neoadjuvant chemotherapy (gemcitabine and cisplatin) plus immune checkpoint inhibitor therapy (LCCC1520 [pembrolizumab] and BLASST-1 [nivolumab]). We found that assessing protein marker expression in the context of tumor architecture improved response prediction.

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Key Words

• BLASST-1
• Bladder cancer
• Digital spatial profiling
• Elastic net regression
• GeoMx
• LCCC1520
• Neoadjuvant chemoimmunotherapy

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MESH Headings

• Humans
• Cisplatin
• Neoadjuvant Therapy/methods
• Gemcitabine
• Nivolumab/therapeutic use
• Proteomics
• Tumor Microenvironment
• Urinary Bladder Neoplasms/drug therapy
• Urinary Bladder Neoplasms/pathology
• Biomarkers, Tumor
• Muscles/pathology
• Immunotherapy
• Neoplasm Invasiveness
• Cystectomy

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Grants

• P30 CA016086 NCI NIH HHS
• R01 CA241810 NCI NIH HHS
• T32 CA244125 NCI NIH HHS

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Affiliation(s)

Wolfgang Beckabir Lineberger Comprehensive Cancer Center, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA; Department of Microbiology and Immunology, UNC School of Medicine, Chapel Hill, NC, USA
Sara E Wobker Lineberger Comprehensive Cancer Center, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA; Department of Pathology, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
Jeffrey S Damrauer Lineberger Comprehensive Cancer Center, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA; Division of Oncology, Department of Medicine, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
Bentley Midkiff Lineberger Comprehensive Cancer Center, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
Gabriela De la Cruz Lineberger Comprehensive Cancer Center, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
Vladmir Makarov Department of Hematology and Oncology, Taussig Cancer Institute, Cleveland Clinic, Cleveland, OH, USA
Leah Flick Lineberger Comprehensive Cancer Center, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
Mark G Woodcock Lineberger Comprehensive Cancer Center, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA; Department of Microbiology and Immunology, UNC School of Medicine, Chapel Hill, NC, USA
Petros Grivas Department of Medicine, Division of Medical Oncology, University of Washington, Fred Hutchinson Cancer Center, Seattle, WA, USA
Marc A Bjurlin Lineberger Comprehensive Cancer Center, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA; Department of Urology, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
Michael R Harrison Division of Medical Oncology, Department of Medicine, Duke Cancer Institute, Duke University, Durham, NC, USA
Benjamin G Vincent Lineberger Comprehensive Cancer Center, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA; Department of Microbiology and Immunology, UNC School of Medicine, Chapel Hill, NC, USA; Division of Hematology, Department of Medicine, UNC School of Medicine, Chapel Hill, NC, USA; Computational Medicine Program, UNC School of Medicine, Chapel Hill, NC, USA; Curriculum in Bioinformatics and Computational Biology, UNC School of Medicine, Chapel Hill, NC, USA
Tracy L Rose Lineberger Comprehensive Cancer Center, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA; Division of Oncology, Department of Medicine, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
Shilpa Gupta Department of Hematology and Oncology, Taussig Cancer Institute, Cleveland Clinic, Cleveland, OH, USA
William Y Kim Lineberger Comprehensive Cancer Center, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA; Division of Oncology, Department of Medicine, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA; Department of Pharmacology, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA; Department of Genetics, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA.
Matthew I Milowsky Lineberger Comprehensive Cancer Center, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA; Division of Oncology, Department of Medicine, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA.

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Near Complete Response to Platinum-based Systemic Chemotherapy in High-risk Upper Tract Urothelial Carcinoma With an ERBB2 Gene Mutation: A Case Report

In bladder urothelial carcinoma, ERBB2 mutations have been associated with favorable response to platinum-based neoadjuvant chemotherapy. However, this association has not been reported in upper tract urothelial carcinoma (UTUC). We describe an excellent response to cisplatin-based chemotherapy in metastatic UTUC with an ERBB2 mutation. Our patient is a 54-year-old female with metastatic UTUC who received systemic cisplatin and gemcitabine. Postchemotherapy imaging demonstrated decreased size of pyelocaliceal mass and decreased retroperitoneal adenopathy compared to initial imaging. Surgical pathology from consolidative resection showed 3 mm residual renal tumor and no viable lymph node disease. Genomic testing demonstrated an ERBB2 gain of function mutation.

FGFR inhibition augments anti-PD-1 efficacy in murine FGFR3-mutant bladder cancer by abrogating immunosuppression

The combination of targeted therapy with immune checkpoint inhibition (ICI) is an area of intense interest. We studied the interaction of fibroblast growth factor receptor (FGFR) inhibition with ICI in urothelial carcinoma (UC) of the bladder, in which FGFR3 is altered in 50% of cases. Using an FGFR3-driven, Trp53-mutant genetically engineered murine model (UPFL), we demonstrate that UPFL tumors recapitulate the histology and molecular subtype of their FGFR3-altered human counterparts. Additionally, UPFL1 allografts exhibit hyperprogression to ICI associated with an expansion of T regulatory cells (Tregs). Erdafitinib blocked Treg proliferation in vitro, while in vivo ICI-induced Treg expansion was fully abrogated by FGFR inhibition. Combined erdafitinib and ICI resulted in high therapeutic efficacy. In aggregate, our work establishes that, in mice, co-alteration of FGFR3 and Trp53 results in high-grade, non-muscle-invasive UC and presents a previously underappreciated role for FGFR inhibition in blocking ICI-induced Treg expansion.

Electronic cigarette, or vaping, product use-associated lung injury (EVALI) in a patient with testicular cancer: A case report

Electronic cigarette, or vaping, product use-associated lung injury (EVALI) is an increasingly recognized entity with the potential for severe pulmonary toxicity. We present the case of a young man first evaluated at a tertiary care center in the United States in 2019 with newly diagnosed testicular cancer with acute respiratory failure, which was initially attributed to possible metastatic disease but eventually determined to be related to EVALI. This case highlights the clinical features of EVALI, the potential diagnostic dilemma that can arise with EVALI when occurring in the setting of malignancy and the importance of inquiring about vaping use among patients with malignancy, especially in adolescents and young adults.

Molecular characterization of plasmacytoid urothelial carcinoma and the impact on treatment implications

Bladder cancer researchers and clinicians have increasingly viewed tumor biology through the lens of genomic and molecular alterations, drastically improving our knowledge of the underlying disease biology. This understanding has led to significant advances in treatment options that allow implementation of a personalized approach to cancer treatment. Large-scale genomic studies initially focused on the most common forms of bladder cancer. However, as genomic and molecular technologies become more widespread and are applied to less common variant histologies, we are gaining additional insight into the unique molecular and genomic characteristics driving the biology of variant histologies of bladder cancer. In this review, we summarize the current state of knowledge of molecular alterations underlying the distinct tumor biology of plasmacytoid urothelial carcinoma and how these alterations may impact treatment options.

Outcomes of Second-Line Therapies in Patients With Metastatic de Novo and Treatment-Emergent Neuroendocrine Prostate Cancer: A Multi-Institutional Study

BACKGROUND

De novo neuroendocrine prostate cancer (NEPC) and treatment-emergent neuroendocrine prostate cancer (T-NEPC) are rare diseases with a poor prognosis. After first-line platinum chemotherapy, there is no consensus on second-line treatments.

PATIENTS AND METHODS

Patients with a pathologic diagnosis of de novo NEPC or T-NEPC between 2000 and 2020 who received first-line platinum and any second-line systemic therapy were selected and standardized clinical data was collected via the electronic health record at each institution. The primary endpoint was overall survival (OS) based on second-line therapy. Secondary endpoints included objective response rate (ORR) to second-line therapy, PSA response, and time on treatment.

RESULTS

Fifty-eight patients (32 de novo NEPC, 26 T-NEPC) from 8 institutions were included. At de novo NEPC or T-NEPC diagnosis, the overall cohort had a median age of 65.0 years (IQR 59.2-70.3) and median PSA of 3.0 ng/dL (IQR 0.6-17.9). Following first-line platinum chemotherapy, 21 patients (36.2%) received platinum chemotherapy, 10 (17.2%) taxane monotherapy, 11 (19.0%) immunotherapy, 10 (17.2%) other chemotherapy, and 6 (16.2%) other systemic therapy. Among 41 evaluable patients, the ORR was 23.5%. The mOS after start of second-line therapy was 7.4 months (95% CI 6.1-11.9).

CONCLUSIONS

In this retrospective study, patients with de novo NEPC or T-NEPC who received second-line therapy were treated with wide variety of treatment regimens, reflecting the lack of consensus in this setting. Most patients received chemotherapy-based treatments. Overall prognosis was poor and ORR was low in the second line regardless of treatment choice.

Diversity, equity, and inclusion in genitourinary clinical trials leading to FDA novel drug approval: An assessment of the FDA center for drug evaluation and research drug trials snapshot

To determine the distribution of race and ethnicity among genitourinary oncology trial participants leading to FDA approval of novel molecular entities/biologics. Secondarily, we evaluated whether the proportion of Black participants in clinical trials increased over time. We quired the FDA Center for Drug Evaluation and Research Drug Trials Snapshot (DTS) between 2015 and 2020 for urologic oncology clinical trials leading to FDA approval of novel drugs. Enrollment data was stratified by race and ethnicity. Cochran-Armitage Trend tests were used to examine changes in Black patient participation over years. Nine clinical trials were identified that led to FDA approval of 5 novel molecular entities for prostate and 4 molecular entities for urothelial carcinoma treatment. Trials for prostate cancer included 5202 participants of which 69.8% were White, 4.0% Black, 11.0% Asian, 3.6% Hispanic, <1% American Indian/Alaska Native or Native Hawaiian/Pacific Islander, 3% other. Trials in urothelial carcinoma had 704 participants of which 75.1% were male, 80.8% White, 2.3% Black, 2.4% Hispanic, <1% American Indian/Alaska Native or Native Hawaiian/Pacific Islander, 5% other. Black participation rates over time did not change for urothelial (P = 0.59) or the combined cancer cohort (P = 0.29). Prostate cancer enrollment trends among Black participant declined over time (P = 0.03). Participants in genitourinary clinical trials leading to FDA approval of novel drugs are overwhelmingly white. Involving stakeholders who represent the needs and interests of underrepresented populations in the design and implementation of clinical trials of novel agents may be a strategy to increase diversity, equity, and inclusion among genitourinary clinical trials.

Metastatic renal cell carcinoma to the pancreas and other sites-a multicenter retrospective study

Background

Metastatic renal cell carcinoma (mRCC) is a heterogenous disease with poor 5-year overall survival (OS) at 14%. Patients with mRCC to endocrine organs historically have prolonged OS. Pancreatic metastases are uncommon overall, with mRCC being the most common etiology of pancreatic metastases. In this study, we report the long-term outcomes of patients with mRCC to the pancreas in two separate cohorts.

Methods

We performed a multicenter, international retrospective cohort study of patients with mRCC to the pancreas at 15 academic centers. Cohort 1 included 91 patients with oligometastatic disease to the pancreas. Cohort 2 included 229 patients with multiples organ sites of metastases including the pancreas. The primary endpoint for Cohorts 1 and 2 was median OS from time of metastatic disease in the pancreas until death or last follow up.

Findings

In Cohort 1, the median OS (mOS) was 121 months with a median follow up time of 42 months. Patients who underwent surgical resection of oligometastatic disease had mOS of 100 months with a median follow-up time of 52.5 months. The mOS for patients treated with systemic therapy was not reached. In Cohort 2, the mOS was 90.77 months. Patients treated with first-line (1L) VEGFR therapy had mOS of 90.77 months; patients treated with IL immunotherapy (IO) had mOS of 92 months; patients on 1L combination VEGFR/IO had mOS of 74.9 months.

Interpretations

This is the largest retrospective cohort of mRCC involving the pancreas. We confirmed the previously reported long-term outcomes in patients with oligometastatic pancreas disease and demonstrated prolonged survival in patients with multiple RCC metastases that included the pancreas. In this retrospective study with heterogeneous population treated over 2 decades, mOS was similar when stratified by first-line therapy. Future research will be needed to determine whether mRCC patients with pancreatic metastases require a different initial treatment strategy.

Funding

Statistical analyses for this study were supported in part by the University of Colorado Cancer Center Support Grant from the NIH/NCI, P30CA046934-30.

Current Status of Perioperative Therapy in Muscle-Invasive Bladder Cancer and Future Directions

PURPOSE OF REVIEW

Cisplatin-based combination chemotherapy has been a standard of care in the perioperative management of muscle-invasive bladder cancer for years, but several novel therapies are under active investigation. This review aims to provide an update on recent relevant literature and a forward look at the future landscape of adjuvant and neoadjuvant therapy in muscle-invasive bladder cancer patients who opt for radical cystectomy.

RECENT FINDINGS

The recent approval of nivolumab as adjuvant therapy established a new treatment option for high-risk patients with muscle-invasive bladder cancer after radical cystectomy. Several phase II studies of chemo-immunotherapy combinations and immunotherapy alone have reported pathological complete responses in the 26-46% range, including studies in cisplatin-ineligible patients. Randomized studies of perioperative chemo-immunotherapy, immunotherapy alone, and enfortumab vedotin are ongoing. Muscle-invasive bladder cancer remains a challenging disease associated with significant morbidity and mortality; however, increasing options in systemic therapy and an increasingly personalized approach to cancer treatment suggest continued future improvements in patient care.

Multi-center, retrospective study of first-line systemic therapy ± immune checkpoint inhibition for metastatic neuroendocrine carcinoma of the urinary tract

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Background: Neuroendocrine, small cell, or large cell carcinoma originating from the urothelium (uro-NE/SCC/LCC) is rare. Outcomes for metastatic disease are dismal. Treatment is extrapolated from small cell lung cancer, for which immune checkpoint inhibitors (ICIs) have modest activity. Preliminary activity has been reported with ICI for uro-NE. We aimed to compare real-world progression-free survival (PFS) and overall survival (OS) between ICI-containing and non-ICI-containing regimens in the first line (1L) metastatic setting for uro-NE/SCC/LCC. Methods: We performed a retrospective study at 11 cancer centers. Patients (pts) who received systemic therapy (2011-2021) for biopsy confirmed metastatic uro-NE/SCC/LCC were included. Pts with metastasis within 6 months of (neo)adjuvant chemotherapy (CT) (n=16) were excluded from 1L analyses. Results: 102 pts with metastatic uro-NE/SCC/LCC were evaluable. 17 (16.7%) had NE histology, 81 (79.4%) SCC, and 4 (3.9%) LCC. NE/SCC/LCC was mixed with urothelial histology in 19 (18.6%). Primary tumors were most often in the bladder (84.3%, n=86), less frequently upper tract (11.8%, n=12) or urethra (3.9%, n=4). 42 pts (41.2%) were previously treated for localized disease, the rest were de novo metastatic (n=60, 58.8%). Pts who received an ICI in any line (n=61) had significantly longer OS (p=0.038) than pts that never received an ICI (n=41). As shown in the table, in the 1L, ICI-containing regimens (n=33) resulted in significantly longer PFS, but not OS or ORR compared to non-ICI regimens (n=53). Subdividing 1L regimens into ICI without CT (n=14), CT without ICI (n=53), or ICI + CT (n=19), both PFS and OS were significantly different with similar ORR. ICI w/o CT had the longest median PFS and OS with an ORR 57.1% comparable to CT regimens. Of 61 pts that received ICI in any line, 14 (23.0%) had an immune-related adverse event of any grade; 11 (18.0%) received steroids. Conclusions: This is the largest ever report of ICI for metastatic uro-NE/SCC/LCC. ICIs were associated with improved outcomes with expected added toxicity. Further prospective investigation of ICI regimens is warranted. [Table: see text]

Dose Intensity in Real-World Patients with Metastatic Renal Cell Carcinoma Taking Vascular Endothelial Growth Factor Receptor Tyrosine Kinase Inhibitors

BACKGROUND

Tyrosine kinase inhibitors (TKIs) that target the vascular endothelial growth factor receptor (VEGFR) are oral therapies used to treat metastatic renal cell carcinoma (mRCC). VEGFR TKI treatment is often complicated by dose-limiting adverse events (AE). We sought to describe dose intensity and clinical outcomes in a real-world cohort of patients treated with VEGFR TKIs to better characterize dosing patterns and toxicity management compared with previously reported clinical trials.

MATERIALS AND METHODS

We conducted a retrospective chart review of sequential patients with mRCC treated with VEGFR TKIs at 1 academic medical center from 2014 to 2021.

RESULTS

139 patients (75% male, 75% white, median age 63 years) were treated with 185 VEGFR TKIs in our real-world cohort. Per International Metastatic RCC Database Consortium criteria, 24% had good risk, 54% intermediate risk, and 22% poor risk mRCC. With their first VEGFR TKI, median relative dose intensity (RDI) was 79%. 52% of patients required a dose reduction, 11% discontinued treatment due to AEs, 15% visited the ED, and 13% were hospitalized for treatment-related adverse events. Cabozantinib had the highest rate of dose reductions (72%) but a low rate of discontinuation (7%). Real-world patients consistently had lower RDI than reported clinical trials with more frequent dose reductions, fewer drug discontinuations, shorter progression-free survival, and shorter overall survival.

CONCLUSION

Real-world patients were less able to tolerate VEGFR TKIs compared to patients treated on clinical trials. Low real-world RDI, high dose reductions, and low overall discontinuation rates can inform patient counseling prior to treatment initiation and during therapy.

Management of Metastatic Clear Cell Renal Cell Carcinoma: ASCO Guideline

PURPOSE

To provide recommendations for the management of patients with metastatic clear cell renal cell carcinoma (ccRCC).

METHODS

An Expert Panel conducted a systematic literature review to obtain evidence to guide treatment recommendations.

RESULTS

The panel considered peer-reviewed reports published in English.

RECOMMENDATIONS

The diagnosis of metastatic ccRCC should be made using tissue biopsy of the primary tumor or a metastatic site with the inclusion of markers and/or stains to support the diagnosis. The International Metastatic RCC Database Consortium risk criteria should be used to inform treatment. Cytoreductive nephrectomy may be offered to select patients with kidney-in-place and favorable- or intermediate-risk disease. For those who have already had a nephrectomy, an initial period of active surveillance may be offered if they are asymptomatic with a low burden of disease. Patients with favorable-risk disease who need systemic therapy may be offered an immune checkpoint inhibitor (ICI) in combination with a vascular endothelial growth factor receptor (VEGFR) tyrosine kinase inhibitor (TKI); patients with intermediate or poor risk should be offered a doublet regimen (no recommendation was provided between ICIs or an ICI in combination with a VEGFR TKI). For select patients, monotherapy with either an ICI or a VEGFR TKI may be offered on the basis of comorbidities. Interleukin-2 remains an option, although selection criteria could not be identified. Recommendations are also provided for second- and subsequent-line therapy as well as the treatment of bone metastases, brain metastases, or the presence of sarcomatoid features. Participation in clinical trials is highly encouraged for patients with metastatic ccRCC.Additional information is available at www.asco.org/genitourinary-cancer-guidelines.

Outcomes of second-line therapies in patients with metastatic de novo small cell prostate cancer (SCPC) and treatment-emergent neuroendocrine prostate cancer (tNEPC)

e17022

Background: De novo SCPC and tNEPC in metastatic castrate resistant prostate cancer (mCRPC) are rare, aggressive cancers with a poor prognosis. After first-line (1L) platinum chemotherapy (PLT), there is no consensus on 2L treatments. This multi-institutional, retrospective study examines practice patterns among clinicians and evaluates the outcomes of patients (pts) with SCPC or tNEPC in the 2L setting. Methods: After IRB approval, pts with a pathologic diagnosis of SCPC or tNEPC (any % of SC or NE histology defined by institutional review) were identified. Pts diagnosed between 2000-2020 who received 1L PLT and any 2L systemic therapy (tx) for SCPC or tNEPC were included. Standardized data collection templates containing demographic, clinical, and pathologic variables were collected. The primary endpoint was objective response rate (ORR) to 2L tx. Secondary endpoints included PSA response, time on 2L treatment, and overall survival (OS) from time of 2L tx. Data was analyzed using descriptive statistics. Results: Forty-two pts (21 SCPC, 21 tNEPC) from 6 institutions were included. At SCPC/tNEPC diagnosis, the overall cohort had a median age of 65.0 years (IQR 60.5, 68.0) and median PSA of 3.0 ng/dL (IQR 0.5, 21.8). The most common sites of metastasis included lymph node (78.6%), bone (54.8%), and liver (52.4%). For 1L tx, 37 pts (88.1%) received PLT and 5 (11.9%) had PLT + immunotherapy (IMM). For treatment to the prostate, 21 (51.2%) had none, 7 (17.1%) radiation (RT), 9 (22.0%) surgery, 3 (7.3%) RT + surgery, and 1 (2.4%) brachytherapy alone. Concurrent ADT was given to 32 pts (76.2%) in the 1L and 2L. At last follow-up, 34 pts (81.0%) were dead, 4 (9.5%) were alive, and 4 (9.5%) were lost to follow-up/censored. For 2L tx, 10 pts (23.8%) received PLT, 8 (19.0%) taxane monotherapy (TAX), 10 (23.8%) IMM, 8 (19.0%) other chemotherapy (CHX), and 6 (14.3%) other tx. Among 38 pts evaluable for response, the ORR was 15.8% (6 pts with PR: 4 PLT, 1 IMM, 1 CHX). PSA response ≥ 50% to 2L tx was seen in 5 of 29 pts with PSA data (17.2%). Other outcomes data are reported in Table. Conclusions: In this retrospective study, pts with SCPC or tNEPC who reached 2L tx received a wide variety of treatment regimens, reflecting the lack of consensus in this tx setting. ORR was low and overall prognosis was poor in the 2L regardless of tx choice. Pts on 2L immunotherapy seemed to have the shortest mOS. [Table: see text]

Outcomes with novel combinations in nonclear cell renal cell carcinoma (nccRCC): ORACLE study

4545

Background: Despite recent advances in the treatment of clear cell RCC, there is a paucity of data to guide management of nccRCC due to the heterogeneity and rarity of these tumors. The clinical activity of combination therapies (including IO-IO, IO-VEGF, VEGF-mTOR) in subtypes of advanced nccRCC is unknown. Methods: In this multicenter retrospective analysis, we evaluated the efficacy of combination systemic therapies in patients with nccRCC. Eligible patients included those with nccRCC as determined by local genitourinary pathology review and receipt of one of three combination regimens during any line treatment (IO-IO, IO-VEGF, mTOR-VEGF). The primary endpoint was objective response rate (ORR) assessed by investigator review. Secondary endpoints were progression- free survival (PFS), disease control rate (DCR), and overall survival (OS). Results: Among 128 included patients, median age was 57 years; 66% were male and 65% white. Histologies included papillary (37%), unclassified (33%), chromophobe (16%), translocation (9%), and other (5 %). Among all patients, 69% had prior nephrectomy; 80% were IMDC intermediate/poor risk; 20% had sarcomatoid and/or rhabdoid differentiation, 27% and 29% had liver and bone metastasis respectively and 63% received combination treatment as first line. Comparison of outcomes based on treatment regimen, line of treatment and subtype is shown in the table. Median PFS and OS were longer with IO/IO and IO/VEGF compared to VEGF/ mTOR at 8.5, 9.5 and 3.7 months and 24.4, 18.2 and 15.4 months respectively. Conclusions: Antitumor activity was observed with novel combinations in nccRCC in both frontline and later line setting. Optimal management of nccRCC remains an unmet need and prospective data is warranted to guide treatment selection for this population. [Table: see text]

Does histologic subtype impact overall survival in observed T1a kidney cancers compared with competing risks? Implications for biopsy as a risk stratification tool

OBJECTIVES

We sought to assess if adding a biopsy proven histologic subtype to a model that predicts overall survival that includes variables representing competing risks in observed, biopsy proven, T1a renal cell carcinomas, enhances the model's performance.

METHODS

The National Cancer Database was assessed (years 2004-2015) for patients with observed T1a renal cell carcinoma who had undergone renal mass biopsy. Kaplan-Meier curves were utilized to estimate overall survival stratified by histologic subtype. We utilized C-index from a Cox proportional hazards model to evaluate the impact of adding histologic subtypes to a model to predict overall survival for each stage.

RESULTS

Of 132 958 T1a renal masses identified, 1614 had biopsy proven histology and were managed non-operatively. Of those, 61% were clear cell, 33% papillary, and 6% chromophobe. Adjusted Kaplan-Meier curves demonstrated a difference in overall survival between histologic subtypes (P = 0.010) with greater median overall survival for patients with chromophobe (85.1 months, hazard rate 0.45, P = 0.005) compared to clear cell (64.8 months, reference group). Adding histology to a model with competing risks alone did not substantially improve model performance (C-index 0.65 vs 0.64 respectively).

CONCLUSIONS

Incorporation of histologic subtype into a risk stratification model to determine prognostic overall survival did not improve modeling of overall survival compared with variables representing competing risks in patients with T1a renal cell carcinoma managed with observation. These results suggest that performing renal mass biopsy in order to obtain tumor histology may have limited utility. Future studies should further investigate the overall utility of renal mass biopsy for observed T1a kidney cancers.

Vigilance is key: Metastatic teratoma in an enlarging retroperitoneal mass after treatment of advanced seminoma – a case report

We present the case of a patient with pure seminoma in the orchiectomy specimen with retroperitoneal mass and a minimally elevated alpha fetoprotein (AFP). The patient received chemotherapy with positron emission tomography (PET) imaging demonstrating minimal fluorodeoxyglucose (FDG) uptake consistent with no viable tumour. Subsequent imaging revealed slow growth in the residual mass with a mildly elevated fluctuating AFP. A robotic-assisted laparoscopic retroperitoneal lymph node dissection was performed revealing metastatic teratoma. This case illustrates the potential for a missed or ‘burned out’ occult NSGCT in a patient with pure seminoma and the importance of post-treatment surveillance. In advanced seminoma, PET may be used to distinguish viable tumour from necrosis in post-chemotherapy residual masses. However, it is unable to distinguish between teratoma and necrosis in non-seminomatous germ cell tumours (NSGCT). Minimally elevated AFP could be a normal variant or signify a component of NSGCT in such cases.

Level of evidence: 4

Non-oncology clinical trial engagement in a nationally representative sample: Identification of motivators and barriers

BACKGROUND

Enrollment in non-oncology clinical trials is often challenging and social determinants that may serve as motivators or barriers to clinical trial enrollment are largely unexplored. We sought to assess engagement in non-oncology clinical trials with a focus on social determinants of health as barriers or motivators toward participation.

METHODS

A cross-sectional analysis of non-cancer respondents was conducted using the Health Information National Trends Survey (HINTS) administered in 2020. Our analytic cohort was comprised of respondents with no reported history of cancer. Our primary outcome of interest was trial engagement defined as receiving an invitation to participate in a clinical trial. Secondary outcomes included participation in a clinical trial and reported motivators and barriers to clinical trial participation.

RESULTS

A total of 3113 respondents with no reported history of cancer were included. Overall, 8.1% of respondents reported being invited to participate in a clinical trial. Amongst those invited to participate, 47.7% reported participating in a clinical trial. Respondents reported that clinical trial participation was motivated "somewhat" or "a lot" by "wanting to get better" (80.5%), "helping other people" (61.4%), "physician encouragement" (60.6%), "getting a chance to try new care" (60.2%), "family friend encouragement" (54.2%), or "getting paid" (50.0%). Overall, 82.5% of all respondents "don't know anything" or have "a little knowledge" about clinical trials. Reported barriers to clinical trial participation including getting transportation, childcare or paid time off work (48.4%) and standard of care not covered by insurance (62.0%) influenced the decision to participate "somewhat" or "a lot."

CONCLUSION

Amongst a nationally representative sample, non-oncology clinical trial invitation is low, but participation amongst those invited is nearly 50%. This highlights the need for clinician engagement in clinical trials. Identifying modifiable social determinants of non-oncologic clinical trial participation may help promote improved engagement.

Phase II Study of Gemcitabine and Split-Dose Cisplatin Plus Pembrolizumab as Neoadjuvant Therapy Before Radical Cystectomy in Patients With Muscle-Invasive Bladder Cancer

PURPOSE

To evaluate the safety and efficacy of gemcitabine and cisplatin in combination with the immune checkpoint inhibitor pembrolizumab as neoadjuvant therapy before radical cystectomy (RC) in muscle-invasive bladder cancer.

METHODS

Patients with clinical T2-4aN0/XM0 muscle-invasive bladder cancer eligible for RC were enrolled. The initial six patients received lead-in pembrolizumab 200 mg once 2 weeks prior to pembrolizumab 200 mg once on day 1, cisplatin 70 mg/m² once on day 1, and gemcitabine 1,000 mg/m² once on days 1 and 8 every 21 days for four cycles. This schedule was discontinued for toxicity and subsequent patients received cisplatin 35 mg/m² once on days 1 and 8 without lead-in pembrolizumab. The primary end point was pathologic downstaging (< pT2N0) with null and alternative hypothesis rates of 35% and 55%, respectively. Secondary end points were toxicity including patient-reported outcomes, complete pathologic response (pT0N0), event-free survival, and overall survival. Association of pathologic downstaging with programmed cell death ligand 1 staining was explored.

RESULTS

Thirty-nine patients were enrolled between June 2016 and March 2020 (72% cT2, 23% cT3, and 5% cT4a). Patients received a median of four cycles of therapy. All patients underwent RC except one who declined. Twenty-two of 39 patients (56% [95% CI, 40 to 72]) achieved < pT2N0 and 14 of 39 (36% [95% CI, 21 to 53]) achieved pT0N0. Most common adverse events (AEs) of any grade were thrombocytopenia (74%), anemia (69%), neutropenia (67%), and hypomagnesemia (67%). One patient had new-onset type 1 diabetes mellitus with ketoacidosis related to pembrolizumab and no patients required steroids for immune-related AEs. Clinicians consistently under-reported AEs when compared with patients.

CONCLUSION

Neoadjuvant gemcitabine and cisplatin plus pembrolizumab met its primary end point for improved pathologic downstaging and was generally safe. A global study of perioperative chemotherapy plus pembrolizumab or placebo is ongoing.

Entinostat induces antitumor immune responses through immune editing of tumor neoantigens

Although immune-checkpoint inhibitors (ICIs) have been a remarkable advancement in bladder cancer treatment, the response rate to single-agent ICIs remains suboptimal. There has been substantial interest in the use of epigenetic agents to enhance ICI efficacy, although precisely how these agents potentiate ICI response has not been fully elucidated. We identified entinostat, a selective HDAC1/3 inhibitor, as a potent antitumor agent in our immune-competent bladder cancer mouse models (BBN963 and BBN966). We demonstrate that entinostat selectively promoted immune editing of tumor neoantigens, effectively remodeling the tumor immune microenvironment, resulting in a robust antitumor response that was cell autonomous, dependent upon antigen presentation, and associated with increased numbers of neoantigen-specific T cells. Finally, combination treatment with anti-PD-1 and entinostat led to complete responses and conferred long-term immunologic memory. Our work defines a tumor cell-autonomous mechanism of action for entinostat and a strong preclinical rationale for the combined use of entinostat and PD-1 blockade in bladder cancer.

Fibroblast growth factor receptor 3 alterations and response to immune checkpoint inhibition in metastatic urothelial cancer: a real world experience

BACKGROUND

FGFR3-altered urothelial cancer (UC) correlates with a non-T cell-inflamed phenotype and has therefore been postulated to be less responsive to immune checkpoint blockade (ICB). Preclinical work suggests FGFR3 signalling may suppress pathways such as interferon signalling that alter immune microenvironment composition. However, correlative studies examining clinical trials have been conflicting as to whether FGFR altered tumours have equivalent response and survival to ICB in patients with metastatic UC. These findings have yet to be validated in real world data, therefore we evaluated clinical outcomes of patients with FGFR3-altered metastatic UC treated with ICB and investigate the underlying immunogenomic mechanisms of response and resistance.

METHODS

103 patients with metastatic UC treated with ICB at a single academic medical center from 2014 to 2018 were identified. Clinical annotation for demographics and cancer outcomes, as well as somatic DNA and RNA sequencing, were performed. Objective response rate to ICB, progression-free survival, and overall survival was compared between patients with FGFR3-alterations and those without. RNA expression, including molecular subtyping and T cell receptor clonality, was also compared between FGFR3-altered and non-altered patients.

RESULTS

Our findings from this dataset confirm that FGFR3-altered (n = 17) and wild type (n = 86) bladder cancers are equally responsive to ICB (12 vs 19%, p = 0.73). Moreover, we demonstrate that despite being less inflamed, FGFR3-altered tumours have equivalent T cell receptor (TCR) diversity and that the balance of a CD8 T cell gene expression signature to immune suppressive features is an important determinant of ICB response.

CONCLUSIONS

Our work in a real world dataset validates prior observations from clinical trials but also extends this prior work to demonstrate that FGFR3-altered and wild type tumours have equivalent TCR diversity and that the balance of effector T cell to immune suppression signals are an important determinant of ICB response.

A real-world evaluation of radium-223 in combination with abiraterone or enzalutamide for the treatment of metastatic castration-resistant prostate cancer

INTRODUCTION

Radium-223, abiraterone, and enzalutamide have each been shown to significantly improve survival as monotherapy in patients with metastatic castration-resistant prostate cancer. However, effects of combination radium-223 plus abiraterone or enzalutamide on survival and safety remain unclear.

PATIENTS AND METHODS

This single-center retrospective cohort study used electronic health record data of patients with metastatic castration-resistant prostate cancer and bone metastases who were treated with radium-223 between April 1, 2014 and February 19, 2019. Patients who received radium-223 monotherapy were compared to patients who received a combination of radium-223 plus either abiraterone or enzalutamide. The primary endpoint was overall survival. Secondary endpoints included progression-free survival, time to symptomatic skeletal event, symptomatic skeletal event-free survival, and incidence of drug-related adverse events. Time-to-event analyses were estimated by log rank tests using Kaplan-Meier curves. Hazard ratios and 95% confidence intervals were derived from Cox proportional hazards models. Chi-square tests evaluated difference in serious adverse events between the two arms.

RESULTS

A total of 60 patients met inclusion criteria (n = 41 in the monotherapy arm, n = 19 in the combination arm). Differences in median overall survival were not observed (12.7 vs. 12.8 months; HR 1.15, 95% CI 0.59-2.23; P = 0.68), but median progression-free survival was significantly longer in the combination arm (7.6 vs. 4.9 months; HR 1.94, 95% CI 1.11-3.40; P = 0.02). Significant differences were not observed in time to first SSE (P = 0.97), SSE-free survival (P = 0.16), or in the overall incidence of serious adverse events (P = 0.45).

CONCLUSION

Combination radium-223 plus abiraterone or enzalutamide did not improve overall survival, but prolonged progression-free survival without increasing the incidence of serious adverse events in metastatic castration-resistant prostate cancer patients with bone metastases. However, these results are limited by small numbers and patient selection inherent in retrospective analysis.

Efficacy of anti-PD(L)1 therapy for patients (Pts) with advanced urothelial carcinoma (aUC) with primary resistance to platinum-based chemotherapy (PC)

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Background: PC remains standard first-line (1L) therapy for aUC. Approximately 15% of pts exhibit primary resistance (P-R) to PC and ∼25% progress by 4 months. PD(L)1 inhibitors yield objective response rates (ORR) of ∼20% in pts with progression after PC; however, it is unclear if this benefit extends to pts with P-R to PC. We examined the efficacy of anti-PD(L)1 in pts with aUC who experienced P-R to 1L PC. Methods: We conducted a multi-institutional retrospective study of pts with aUC who experienced P-R to PC and were subsequently treated with single-agent anti-PD(L)1 therapy. Eligibility included pts with unresectable or metastatic disease diagnosed after January 1, 2017. P-R to PC was defined as radiographic progression by RECISTv1.1 within 12 weeks from initiation of PC. Pts who developed metastatic disease while receiving (neo)adjuvant PC were eligible. Clinicopathologic variables were collected. ORR to anti-PD(L)1 was the primary endpoint. Secondary endpoints included time to treatment failure (TTF, defined as time from start of anti-PD(L)1 therapy to next line of therapy, hospice or death) and overall survival (OS) were estimated using Kaplan-Meier method. Multivariate (MV) analysis using Cox regression evaluating factors associated with OS was performed. Results: Overall, 42 pts were included: 74% male, median age 65 (28-90); 79% ever smokers; 21% mixed histology; 31% received definitive locoregional therapy. Metastatic sites at diagnosis of aUC included: lymph node only (19%), liver (29%), bone (38%) and lung (33%). At diagnosis of aUC, ECOG PS was 0 in 26%, 1 in 52% and unknown in 21%. 1L PC included cisplatin (76%) and carboplatin (24%) based regimens. Anti-PD(L)1 was received either 2L (98%) or 3L (2%). Overall, ORR to anti-PD(L)1 was 17%: CR (2%), PR (14%), SD (14%), PD (57%) and unknown (12%). Of the 24 pts with PD as best response to anti-PD(L)1, only 9 (38%) received subsequent therapy. Overall, median TTF was 4.2 mo (95% CI 2.8-6.7 mo) and median OS was 7.4 mo (95% CI 4.2-11.1 mo). ORR in patients with a PDL1 combined positive score ≥ 10% (n=6) was 0%: 1 SD and 5 PD. MV analysis for OS from start of anti-PD(L)1 is shown (Table). Conclusions: P-R to PC portends a poor prognosis in pts with aUC. While a subset of patients may respond to anti-PD(L)1 therapy, the majority of pts do not derive benefit. Alternative agents, e.g. antibody drug conjugates and FGFR inhibitors, and combination-therapy should be investigated for this high risk population.[Table: see text]

Pembrolizumab (pembro) in combination with gemcitabine (Gem) and concurrent hypofractionated radiation therapy (RT) as bladder sparing treatment for muscle-invasive urothelial cancer of the bladder (MIBC): A multicenter phase 2 trial

4504

Background: Trimodality bladder preservation therapy (TMT) is a standard treatment option for clinically localized MIBC with curative intent. Pembro has shown activity in MIBC in the neoadjuvant setting and may combine well with TMT to improve outcomes. This trial evaluated the safety and efficacy of pembro added to TMT in MIBC. Methods: This multicenter phase 2 trial included pts with cT2 – T4aN0M0 MIBC who declined or were ineligible for cystectomy (RC), ECOG PS 0/1, eGFR > 30 cc/min, and no contraindications to pelvic RT or pembro. No perioperative chemotx for MIBC was permitted. Pts received pembro 200 mg x 1 followed 2-3 weeks by maximal TURBT and then whole bladder RT (52 Gy/20 fx; IMRT preferred) with twice wkly gem 27 mg/m2 and pembro Q3 wks x 3 treatments. 12 wks post-RT, CT/MR AP, TUR of tumor bed and cytology were performed to document response. Up to 6 pts were enrolled to a safety cohort (SC) followed by 48 pts in efficacy cohort (EC). The primary endpt is 2-yr bladder-intact disease-free survival (BIDFS: first of MIBC or regional nodal recurrence, distant metastases, or death) assessed by serial cysto/cytology and CT/MRI. EC had 85% power to detect a 20% absolute improvement in 2-yr BIDFS rate over 60% historical rate (RTOG Pooled analysis; Mak JCO 2014). Key secondary endpts were safety, 12 wks CR rate, metastases-free survival and overall survival. Tumor tissue was collected at study entry, maximal TURBT and post-treatment TUR of tumor bed with serial PBMCs for correlative analyses. Results: From 5/2016 to 10/2020, 54 pts (6 SC, 48 EC; 72% M) enrolled at 5 centers; Median age 67 (65-89) for SC and 74 (51-97) for EC. C-stage (74% cT2, 22% cT3, and 4% cT4). 39 (72%) declined RC. All 6 pts in SC and 42/48 (88%) of EC pts completed all study therapy; 1/48 (2%), 2/48 (4%), and 4/48 (8%) discontinued RT/Gem, Gem or Pembro, respectively, most often due to toxicity. As of 1/2021 (median F/U 40.9 mos (38.6-50.8) SC and 11.7 mos (0.6 – 32.2) EC), no recurrences in SC, and 12/48 EC pts had any recurrence (6 NMIBC, 0 MIBC, 2 regional and 4 distant). The estimated 1 yr BIDFS rate is 77% (95% CI: 0.60-0.87). 12 wks CR rate was 100% in SC and 83% for EC (1 PR, 3 NR, 1 Progression, 11 NE; 2 still on active study). In the EC, 35% of pts had a Gr ≥3 TEAE (Gr 3 events included UTI 8%, diarrhea 4%, colitis 4%, bladder pain/obstruction 4%, neutropenia 2%, thrombocytopenia 2%). Notable Pembro Gr ≥3 TRAE included 3 pts (6%) Gr 3 GI toxicity and 1 pt Gr 4 colonic perforation. 1 patient died due to fungemia, unrelated to study therapy. Conclusions: Pembro added to hypofractionated RT and twice weekly gem was well-tolerated with promising efficacy in this early analysis. Pembro-related toxicity was consistent with prior monotherapy trials. Selected correlative analyses from serially collected blood and tissue specimens will be presented. Clinical trial information: NCT02621151.

Outcomes with novel combinations in non-clear cell renal cell carcinoma(nccRCC): ORACLE study

4580

Background: Despite advances in the treatment of clear cell RCC, there is a paucity of data to guide management of nccRCC due to the heterogeneity and rarity of these tumors. The clinical activity of new combination therapies (including immunotherapy (IO), anti-vascular endothelial growth factor inhibitors (VEGF), and mammalian target of rapamycin (mTOR) inhibitors) in metastatic nccRCC is not known. Methods: In this multicenter retrospective analysis, we explored the efficacy of combination systemic therapies in patients with nccRCC. Baseline and follow-up demographic, clinical, treatment, and radiographic data were collected. The primary endpoint was objective response rate (ORR) assessed by investigator review. Secondary endpoints include progression- free survival (PFS), disease control rate (DCR), median duration of response (DOR), overall survival (OS), and biomarker correlates. Results: Among 66 included patients, median age was 59 yr; 60% were male and 62% white. Histologies included papillary (38%), chromophobe (17%), unclassified (24%), translocation (12%), and other (9 %). Sarcomatoid and/or rhabdoid differentiation was present in 18%, 70% had prior nephrectomy, 86% were IMDC intermediate/poor risk, 29% and 32% had liver and bone metastasis respectively. 67% received combination treatment in the first line. Comparison of outcomes based on treatment regimen is shown in the table. Conclusions: Antitumor activity was observed with novel combinations in nccRCC which warrants further prospective studies. Response rates and survival with combination therapy in this dataset remain inferior to rates seen in clear cell RCC.[Table: see text]

Treatment outcomes in renal cell carcinoma patients with metastases to the pancreas and other sites

4557

Background: Metastatic RCC (mRCC) involving the pancreas is distinct from RCC involving other metastatic sites and is characterized by an indolent clinical course, heightened angiogenesis, and an inflamed stroma (PMID: 32271170). We previously reported on outcomes of RCC patients (pts) with pancreatic oligometastasis (ASCO GU 2020). We now report on outcomes in pts with mRCC involving the pancreas in conjunction with other metastases (mets). Methods: We conducted a retrospective, multi-institutional study of mRCC pts with mets to the pancreas and other sites. Data on pt demographics, tumor characteristics, systemic therapy, and outcomes were collected. Pts were classified based on treatment category: immunotherapy (IO) or vascular endothelial growth factor/receptor inhibitors (VEGFI). Outcomes measured included objective response rates (ORR), time-on-treatment (TOT), and overall survival (OS). Results: The analysis included 229 pts from 9 institutions, diagnosed between 1985-2020. Of these, 211 (92%) had clear-cell histology; 131 (57%) had nephrectomy; 41 (18%) had local pancreas-directed therapy; 111 (48%) had synchronous presentation of disease in the pancreas and other sites at time of mets. IMDC risk was favorable in 33%, intermediate in 41%, poor in 11%, and unknown in 15% pts. Median lines of therapy was 2 (range 0-9). Of 219 pts who received first-line (1L) therapy, 151 (69%) had VEGFI therapy, 41 (19%) had IO, and 18 (8%) had VEGFI/IO combination (Table). The IO group included 21 pts on checkpoint inhibitor (CPI), 16 pts on HD-IL2, 4 pts on other IO. 1L ORR was 39.7% for VEGFI (95% CI 31.8-48.0) and 31.7% for IO (95% CI 18.1-48.1) and was not statistically significant (NS, OR 1.4, 95% CI 0.65-3.23, p = 0.371). Median TOT for 1L therapy was 11.6m for VEGFI and 6.5m for IO (p = 0.0106). With a median follow-up of 51.5m, the median OS (mOS) for all pts from time of metastatic disease was 7.7 years (y) (95% CI 6.3-10.3). The mOS for pts who received 1L VEGFI was 7.6y (95% CI 5.5-9.5) and was not reached (NR) for those who got 1L IO (95%CI 6.5-NR); this difference was significant with an unadjusted p-value of 0.029. The pair-wise comparison between mOS of the 1L CPI subgroup compared to that of the 1L VEGFI group was significant (p = 0.0148). Conclusions: Consistent with the literature, mRCC pts with involvement of the pancreas in this study have prolonged OS compared to historical OS for the standard mRCC population. Additionally, our findings suggest that the choice of first-line therapy may impact outcomes. Additional analyses will be presented.[Table: see text]

Incidence and Prediction of Immune Checkpoint Inhibitor-related Nephrotoxicity

Immune checkpoint inhibitors (ICIs) may cause immune-related adverse events that can affect any organ system, including the kidneys. Our study aimed to better characterize the incidence of and predictive factors for immune-related acute kidney injury (irAKI) and evaluate steroid responsiveness. An institutional database (Carolina Data Warehouse) was queried for patients who received ICIs and subsequently had substantial AKI, defined as a doubling of baseline creatinine. A retrospective chart review was performed to determine the cause of AKI. AKI events determined to be immune-related were further analyzed. A total of 1766 patients received an ICI between April 2014 and December 2018. A total of 123 (7%) patients had an AKI within 1 year of the administration of the first ICI dose. 14 (0.8% of all patients who received ICIs) of the AKI events were immune-related. History of an autoimmune disease (N=2, 14%, P=0.04) or history of other immune-related adverse events (irAEs) (N=8, 57%, P=0.01) was a significant predictor of irAKI. Of 14 irAKI patients, 9 received steroids with renal function improving to baseline in 5 patients, improving but not to baseline in 2, and 2 without improvement in renal function, including 1 becoming dialysis-dependent. Age, sex, urinalysis findings, and primary tumor site were not associated with irAKI. irAKI is relatively uncommon but likely under-recognized. Underlying autoimmune disease and history of nonrenal ICI-related irAEs are associated with irAKI. Early recognition and steroid administration are important for a positive outcome.

Phase II study of gemcitabine and split-dose cisplatin plus pembrolizumab as neoadjuvant therapy prior to radical cystectomy (RC) in patients with muscle-invasive bladder cancer (MIBC)

396

Background: Cisplatin-based neoadjuvant chemotherapy is standard of care in MIBC with improved pathologic response and overall survival (OS) compared to RC alone. Pembrolizumab (pembro) is active in high-risk non-muscle invasive and metastatic bladder cancer and is generally well tolerated. This phase II trial evaluated the safety and efficacy of gemcitabine and split-dose cisplatin (GC) + pembro as neoadjuvant therapy prior to RC (NCT02690558). Methods: Patients with clinical T2-4a N0/X M0 urothelial carcinoma of the bladder eligible for RC were enrolled. Patients received pembro 200mg on day 1 with cisplatin 35mg/m2 and gemcitabine 1000mg/m2 on days 1 and 8 every 3 weeks for 4 cycles, followed by RC within 4-8 weeks. The first 6 patients received full-dose cisplatin (70mg/m2 on day 1) and a lead-in pembro dose; this schedule was discontinued for excess toxicity. Primary endpoint was pathologic downstaging rate ( < pT2) with the null and alternative hypothesis rates = 35% and 55%, respectively. Secondary endpoints were toxicity, pT0 rate, event free survival, and OS. Exploratory objectives include association of response with molecular subtype and post-treatment changes in immune microenvironment (predicted neoantigens, immune gene expression, and T cell receptor repertoire). Results: Between May 2016 and July 2020, 39 patients were enrolled (72% cT2, 23% cT3, 5% cT4a) with a median age of 66 and 82% male. Patients received a median of 4 cycles of therapy. All patients underwent RC except one who declined but is included in intention to treat analysis. Rate of < pT2N0 was 56% (22/39) and pT0N0 rate was 36% (14/39). Most common adverse events (AEs) of any grade were thrombocytopenia (29/39; 74%), anemia (27/39; 69%), neutropenia (26/39; 67%), and hypomagnesemia (26/39; 67%). Most common grade 3/4 AEs were neutropenia (16/39; 41%), thrombocytopenia (13/39; 33%), febrile neutropenia (5/39; 13%), and anemia (4/39; 10%). One patient had new onset type 1 diabetes mellitus with ketoacidosis related to pembrolizumab and no patients required steroids for immune-related AEs. Nine patients (23%) discontinued GC + pembro due to AEs, including 4 of the 6 patients who received full-dose cisplatin with pembro lead-in. Survival data are not yet mature and correlative studies are ongoing. Conclusions: Neoadjuvant GC + pembro was generally safe and met its primary endpoint for improved pathologic downstaging. Correlative analyses are ongoing. Additional investigation of this combination is warranted. Clinical trial information: NCT02690558.

Patterns of Recurrence, Detection Rates, and Impact of 18-F Fluciclovine PET/CT on the Management of Men With Recurrent Prostate Cancer

OBJECTIVE

To evaluate the characteristics of FACBC PET/CT in detecting recurrent prostate cancer after radiation or prostatectomy. The secondary aim was to determine the impact of FACBC PET/CT on radiation treatment recommendations in men with biochemical recurrence postprostatectomy.

METHODS

This is a single center retrospective study of men who underwent an FACBC PET/CT for rising PSA after definitive prostate cancer therapy. Detection rates in men with recurrence following any definitive treatment were compared at different PSA levels and anatomical sites. Radiotherapy treatment recommendations for patients postprostatectomy based on conventional imaging findings were compared to recommendations based on FACBC PET/CT findings.

RESULTS

A total of 103 men underwent imaging with FACBC PET/CT. 74.8% (77) had lesions consistent with sites of prostate cancer recurrence. At PSA thresholds of <1, 1-2, and >2 ng/mL lesions were detected in 35.5%, 63.6%, and 95.2% of patients respectively (P <.001). The most common site of recurrence was outside of the pelvis (37). Detection of extraprostatic or extrapelvic recurrence was observed in 45.5% of men in the PSA tertile <1ng/mL. FACBC PET/CT results led to changes to the recommended radiotherapy treatment plan in 44.1% (15/34) of men with recurrence following radical prostatectomy.

CONCLUSION

FACBC PET/CT demonstrated increased detection of recurrent prostate cancer with increasing PSA levels. Most recurrences were found outside the pelvis. Results of FACBC PET/CT changed radiotherapy management decisions in men treated with prostatectomy, supporting its use in localizing sites of disease recurrence in men with prostate cancer.

Secondary Immune Thrombocytopenia in Metastatic Renal Cell Carcinoma: A Case Report and Discussion of the Literature

Immune thrombocytopenia (ITP) is a rare paraneoplastic syndrome of solid tumor malignancies. In previously described cases of renal cell carcinoma (RCC) associated with secondary ITP, treatment has consisted of nephrectomy, splenectomy, and corticosteroids. Here, we describe a case of metastatic RCC presenting with a right ventricular mass and subsequent development of secondary ITP. The clinical course was complicated by recurrent severe thrombocytopenia despite treatment with corticosteroids, rituximab, and thrombopoietin receptor agonists, precluding cancer-directed therapy and anticoagulation. Further study is needed to determine the optimal management strategy for malignancy-associated ITP.

Overall Survival of Biopsy-confirmed T1B and T2A Kidney Cancers Managed With Observation: Prognostic Value of Tumor Histology

INTRODUCTION

The natural history of T1b (4-7 cm) or T2a (> 7-10 cm) kidney cancers managed with observation is not well-understood. The aim of our study was to determine if the addition of histologic subtype to a predictive model of overall survival (OS) that includes covariates for competing risks in observed, biopsy-proven, T1b and T2a renal cell carcinomas (RCCs) improves the model's performance.

MATERIALS AND METHODS

We queried the National Cancer Database for patients with biopsy-proven stage T1b or T2a RCC and managed nonoperatively between 2004 and 2015. OS was estimated by Kaplan-Meier curves based on histologic subtype. The concordance index (c-index) from a Cox proportional hazards model was used to estimate the extent to which histologic subtypes predict survival for each stage when included in a model along with competing risks of age, gender, race/ethnicity, insurance status, area-level socioeconomic indicators, Charlson-Deyo index, and tumor grade.

RESULTS

A total of 937 patients (754 with T1b and 185 with T2a) with biopsy-proven RCC were identified. Kaplan-Meier analysis suggested differences in OS by histologic subtype where sarcomatoid, followed by clear cell, papillary, and chromophobe, had the highest mortality risk at 1, 3, and 5 years. However, there was marginal improvement in the multivariable model of OS using competing risks and histology (c-index, 0.64 and 0.697) compared with competing risks alone (c-index, 0.631 and 0.671) for T1b and T2a RCCs, respectively.

CONCLUSIONS

In patients with T1b or T2a RCC managed with observation, incorporation of histologic subtype into a risk-stratification model to determine prognostic OS did not improve modeling of OS compared with variables representing competing risks. Histologic subtype of observed T1b and T2a RCC appears to have prognostic OS value when not considering competing risks. These findings may impact the usefulness of renal biopsy to inform decision-making when managing patients with T1b and T2a renal tumors with observation.

Optimized Management of Nivolumab and Ipilimumab in Advanced Renal Cell Carcinoma: A Response-Based Phase II Study (OMNIVORE)

PURPOSE

In this phase II response-adaptive trial, we investigated the rational application of immune checkpoint blockade in renal cell carcinoma (RCC; ClinicalTrials.gov identifier: NCT03203473).

METHODS

We enrolled patients with metastatic RCC with no prior checkpoint inhibitor exposure. All patients received nivolumab alone with subsequent arm allocation based on response. Patients with a confirmed partial response (PR) or complete response (CR) within 6 months discontinued nivolumab and were observed (arm A). Patients with stable disease or progressive disease (PD) after no more than 6 months of nivolumab received two doses of ipilimumab (arm B). The primary endpoints were the proportion of patients with PR/CR at 1 year after nivolumab discontinuation (arm A) and proportion of nivolumab nonresponders who converted to PR/CR after ipilimumab (arm B).

RESULTS

Overall, 83 patients initiated treatment, of whom 96% had clear-cell histology, 51% were treatment naïve, and 67% had intermediate/poor-risk disease. Median follow-up was 19.5 months. Within 6 months, induction nivolumab resulted in a confirmed PR in 12% of patients (n = 10). Fourteen patients were not allocated to a study arm (seven because of toxicity, seven because of PD). Twelve patients (14%) were allocated to arm A and discontinued nivolumab, of whom five (42%; 90% CI, 18% to 68%) remained off nivolumab at ≥ 1 year. Of 57 patients (69%) allocated to arm B, two patients converted to a confirmed PR (4%; 90% CI, 1% to 11%), and no CRs were observed.

CONCLUSION

In this study, nivolumab followed by two doses of ipilimumab resulted in no CRs and a low PR/CR conversion. The number of patients evaluated for nivolumab discontinuation was too small to assess the value of this approach. Currently, our data do not support a response-adaptive strategy for checkpoint blockade in advanced RCC.

Development and validation of a NanoString BASE47 bladder cancer gene classifier

Background

Recent molecular characterization of urothelial cancer (UC) has suggested potential pathways in which to direct treatment, leading to a host of targeted therapies in development for UC. In parallel, gene expression profiling has demonstrated that high-grade UC is a heterogeneous disease. Prognostic basal-like and luminal-like subtypes have been identified and an accurate transcriptome BASE47 classifier has been developed. However, these phenotypes cannot be broadly investigated due to the lack of a clinically viable diagnostic assay. We sought to develop and evaluate a diagnostic classifier of UC subtype with the goal of accurate classification from clinically available specimens.

Methods

Tumor samples from 52 patients with high-grade UC were profiled for BASE47 genes concurrently by RNAseq as well as NanoString. After design and technical validation of a BASE47 NanoString probeset, results from the RNAseq and NanoString were used to translate diagnostic criteria to the Nanostring platform. Evaluation of repeatability and accuracy was performed to derive a final Nanostring based classifier. Diagnostic classification resulting from the NanoString BASE47 classifier was validated on an independent dataset (n = 30). The training and validation datasets accurately classified 87% and 93% of samples, respectively.

Results

Here we have derived a NanoString-platform BASE47 classifier that accurately predicts basal-like and luminal-like subtypes in high grade urothelial cancer. We have further validated our new NanoString BASE47 classifier on an independent dataset and confirmed high accuracy when compared with our original Transcriptome BASE47 classifier.

Conclusions

The NanoString BASE47 classifier provides a faster turnaround time, a lower cost per sample to process, and maintains the accuracy of the original subtype classifier for better clinical implementation.

Trends in Initial Systemic Therapy for Elderly Patients with Metastatic Clear Cell Renal Cell Carcinoma

BACKGROUND

The treatment landscape for metastatic clear cell renal cell carcinoma (mRCC) is rapidly changing. It is unknown how adoption of new types of therapies may differ by patient age.

OBJECTIVE

To compare trends in first-line therapy use for older (≥70 years) and younger (< 70) patients with mRCC before and after approval of nivolumab in 2015.

METHODS

Using the National Cancer Database, we assessed trends in first-line therapy use by calculating the proportion of patients receiving targeted therapy, immunotherapy, or no systemic therapy by year of diagnosis. Initial systemic treatment was compared for patients diagnosed in 2016 with patients diagnosed in 2011 as a control group prior to nivolumab approval. Multivariable regression analysis was used to evaluate the interaction between year of diagnosis and elderly status for use of first-line immunotherapy or targeted therapy.

RESULTS

From 2006 to 2016, the proportion of patients receiving any type of systemic therapy increased from 43.7% to 56.5%. On stratified multivariable regression analysis, older patients diagnosed in 2016 were 17.3 times more likely to receive first-line immunotherapy compared to those diagnosed in 2011, while younger patients were 2.3 times more likely. There was no change in targeted therapy use over this time regardless of patient age.

CONCLUSIONS

The rate of adoption of first-line immunotherapy was particularly pronounced for elderly compared to younger patients. While first-line use of immunotherapy may have allowed elderly patients to receive systemic therapy that they otherwise would not, the efficacy of these drugs in elderly patients deserves further study.

Underrepresentation of genitourinary cancers in studies of venous thromboembolism (VTE) prophylaxis

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Background: Significant advances in the management of VTE in cancer have led to a recent ASCO clinical practice update for VTE prophylaxis and treatment in patients with cancer. Genitourinary (GU) cancers (including bladder, kidney, prostate, testicular) have a high incidence of VTE, but also frequent bleeding complications, and it is not clear if patients with GU cancers are adequately represented in studies of VTE prophylaxis. We sought to determine the frequency of inclusion of patients with GU cancers in prospective studies of VTE prophylaxis. Methods: A systematic review of the literature using MEDLINE (inception to January 2020) was conducted. We included randomized controlled trials that compared thromboprophylaxis to placebo or best supportive care in patients with an established diagnosis of cancer. Observational studies, case series, and case reports were excluded. The primary outcome was proportion of patients with GU malignancies included within the trials. Results: A total of 137 articles were identified under the original search and 7 underwent full text review. A total of 6066 patients were included in 7 thromboprophylaxis trials, of which only 119 (2.0%) had a defined GU malignancy (Table). Given the heterogeneity of the GU cancers represented in each study, and the small numbers of patients included with GU cancers, a patient-level meta-analysis among GU patients in this population was not performed. Conclusions: In spite of the high risk for VTE in GU cancers, in particular bladder and testicular cancer, GU cancers are underrepresented in prospective randomized trials investigating VTE prophylaxis. To ensure appropriate decision making for each individual patient, future prospective trials must ensure adequate representation of patients with GU cancers to better understand the potential role for VTE prophylaxis in this high-risk population.[Table: see text]

Optimized management of nivolumab (Nivo) and ipilimumab (Ipi) in advanced renal cell carcinoma (RCC): A response-based phase II study (OMNIVORE)

5005

Background: Nivo + Ipi is an established first-line treatment (tx) for advanced RCC. We hypothesized that the addition of CTLA-4 blockade may not be required for all patients (pts). Furthermore, the optimal duration of Nivo maintenance in responding pts is unknown. In this phase II response-adaptive trial, we investigate the sequential addition of 2 doses of Ipi to induce response in Nivo non-responders (NR) and duration of Nivo in responding pts (NCT03203473). Methods: We enrolled pts with advanced RCC with no prior checkpoint inhibitor exposure. All pts received Nivo alone with subsequent arm allocation based on RECISTv1.1 response within 6 months (mos) of tx. Pts with a confirmed partial response (PR) or complete response (CR) within 6 months (mos) discontinued Nivo and were observed (Arm A). Arm A pts reinitiated Nivo if they developed progressive disease (PD); Ipi was added to Nivo if PD persisted or recurred. Pts with stable disease (SD) or PD after no more than 6 mos of Nivo alone received 2 doses of Ipi (Arm B). The primary endpoints were the proportion with PR/CR at 1-year (yr) after Nivo discontinuation (Arm A) and proportion of Nivo NR who convert to PR/CR after adding Ipi (Arm B). Results: 83 pts initiated tx of whom 99% had ECOG 0-1, 96% clear cell RCC, 51% tx-naïve, and 69% IMDC intermediate/poor risk. Median follow-up was 17.0 mos. 15 pts were not allocated to an arm [7 withdrew for PD, 7 withdrew for toxicity, 1 still on tx with unconfirmed PR (uPR)]. At 6 mos, induction Nivo resulted in a confirmed PR in 11% of pts (n=9/83): 12% (n=5/42) tx-naïve, 10% (4/41) prior tx, 8% (n=1/13) favorable risk, 11% (n=8/70) intermediate/poor risk (Table). 11 pts (13%: 9 PR, 1 uPR, 1 SD) were allocated to Arm A, of whom 5 (45%, 90% CI 20-73%) remained off Nivo at ≥ 1 yr. Of 57 pts (69%) allocated to Arm B, 2 pts converted to a PR (4%, 90% CI 1-11%), both of whom had prior tx and PD as best response to Nivo alone. Grade 3-4 treatment related adverse events (TrAE) occurred in 7% (n=6/83) on induction Nivo and in 23% (n=13/57) on Arm B (Nivo + Ipi). Conclusions: We cannot currently recommend a strategy of Nivo followed by response-based addition of Ipi due to the absence of CR and low PR/CR conversion rate (4%). Though a subset of pts treated with Nivo alone can maintain durable responses off tx at 1-yr, early Nivo discontinuation in the absence of toxicity cannot currently be recommended. Investigation into biomarkers to guide tx is ongoing. Clinical trial information: NCT03203473 . [Table: see text]

A Systematic Review of Systemic Treatment Options for Advanced Non-Clear Cell Renal Cell Carcinoma

INTRODUCTION

There have been a number of recent advances in the management of advanced clear cell renal cell carcinoma (ccRCC). However, the majority of these studies excluded patients with non-clear cell RCC (nccRCC), and optimal management of nccRCC remains unknown.

MATERIALS AND METHODS

A systematic review of the literature was performed according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines to evaluate systemic treatment options in locally advanced or metastatic nccRCC between 2000-2019. Randomized controlled trials, single-arm phase II-IV trials, and prospective analyses of medication access programs were included. The primary outcome measures were progression free survival (PFS), overall survival (OS), and objective response rate (ORR).

RESULTS

A total of 31 studies were included in the final analysis. There was the highest level of evidence to support first-line treatment of nccRCC with sunitinib. Additional single-arm trials support the use of other vascular endothelial growth factor (VEGF) inhibitors with axitinib and pazopanib, as well as mammalian target of rapamycin (mTOR) inhibition with temsirolimus or everolimus +/- bevacizumab. Immune checkpoint inhibition has an emerging role in nccRCC, but optimal sequencing of available options is not clear. Prospective data to support the use of newer immunotherapy combinations are lacking. Treatment for collecting duct carcinoma remains platinum-based chemotherapy.

CONCLUSIONS

The availability of randomized trials in nccRCC is limited, and most studies include outcomes for nccRCC as a group, making conclusions about efficacy by subtype difficult. This systematic review supports consensus guidelines recommending sunitinib or clinical trial enrollment as preferred first-line treatment options for nccRCC, but also suggests a more nuanced approach to management and new options for therapy such as immune checkpoint inhibition.

Prognostic Value of Histologic Subtype and Treatment Modality for T1a Kidney Cancers

INTRODUCTION

To evaluate overall survival (OS) of T1a kidney cancers stratified by histologic subtype and curative treatment including partial nephrectomy (PN), percutaneous ablation (PA), and radical nephrectomy (RN).

MATERIALS AND METHODS

We queried the National Cancer Data Base (2004-2015) for patients with T1a kidney cancers who were treated surgically. OS was estimated by Kaplan-Meier curves based on histologic subtype and management. Cox proportional regression models were used to determine whether histologic subtypes and management procedure predicted OS.

RESULTS

46,014 T1a kidney cancers met inclusion criteria. Kaplan Meier curves demonstrated differences in OS by treatment for clear cell, papillary, chromophobe, and cystic histologic subtypes (all p < 0.001), but no differences for sarcomatoid (p = 0.110) or collecting duct (p = 0.392) were observed. Adjusted Cox regression showed worse OS for PA than PN among patients with clear cell (HR 1.58, 95%CI [1.44-1.73], papillary RCC (1.53 [1.34-1.75]), and chromophobe RCC (2.19 [1.64-2.91]). OS was worse for RN than PN for clear cell (HR 1.38 [1.28-1.50]) papillary (1.34 [1.16-1.56]) and chromophobe RCC (1.92 [1.43-2.58]). Predictive models using Cox proportional hazards incorporating histology and surgical procedure alone were limited (c-index 0.63) while adding demographics demonstrated fair predictive power for OS (c-index 0.73).

CONCLUSIONS

In patients with pathologic T1a RCC, patterns of OS differed by surgery and histologic subtype. Patients receiving PN appears to have better prognosis than both PA and RN. However, the incorporation of histologic subtype and treatment modality into a risk stratification model to predict OS had limited utility compared with variables representing competing risks.

Pilot Study of [18F] Fluorodeoxyglucose Positron Emission Tomography (FDG-PET)/Magnetic Resonance Imaging (MRI) for Staging of Muscle-invasive Bladder Cancer (MIBC)

INTRODUCTION

Computed tomography (CT) has limited diagnostic accuracy for staging of muscle-invasive bladder cancer (MIBC). [¹⁸F] Fluorodeoxyglucose positron emission tomography (FDG-PET)/magnetic resonance imaging (MRI) is a novel imaging modality incorporating functional imaging with improved soft tissue characterization. This pilot study evaluated the use of preoperative FDG-PET/MRI for staging of MIBC.

PATIENTS AND METHODS

Twenty-one patients with MIBC with planned radical cystectomy were enrolled. Two teams of radiologists reviewed FDG-PET/MRI scans to determine: (1) presence of primary bladder tumor; and (2) lymph node involvement and distant metastases. FDG-PET/MRI was compared with cystectomy pathology and computed tomography (CT).

RESULTS

Eighteen patients were included in the final analysis, most (72.2%) of whom received neoadjuvant chemotherapy. Final pathology revealed 10 (56%) patients with muscle invasion and only 3 (17%) patients with lymph node involvement. Clustered analysis of FDG-PET/MRI radiology team reads revealed a sensitivity of 0.80 and a specificity of 0.56 for detection of the primary tumor with a sensitivity of 0 and a specificity of 1.00 for detection of lymph node involvement when compared with cystectomy pathology. CT imaging demonstrated similar rates in evaluation of the primary tumor (sensitivity, 0.91; specificity, 0.43) and lymph node involvement (sensitivity, 0; specificity, 0.93) when compared with pathology.

CONCLUSIONS

This pilot single-institution experience of FDG-PET/MRI for preoperative staging of MIBC performed similar to CT for the detection of the primary tumor; however, the determination of lymph node status was limited by few patients with true pathologic lymph node involvement. Further studies are needed to evaluate the potential role for FDG-PET/MRI in the staging of MIBC.

Predictive value of fibroblast growth factor receptor (FGFR) alterations on anti-PD-(L)1 treatment outcomes in patients (Pts) with advanced urothelial cancer (UC): Pooled analysis of real-world data

493

Background: The tumor microenvironment in UC harboring FGFR gene alterations is characterized by decreased T-cell infiltration and low immune marker expression, potentially implicating suboptimal response to immune checkpoint inhibitors. The association between FGFR gene mutations/fusions and anti-PD-(L)1 treatment outcomes in advanced UC was assessed using real-world pt data. Methods: A pooled dataset of matched clinical and genomic data for advanced UC pts treated with anti-PD-(L)1 in any line from the Bladder Cancer Research Initiative for Drug Targets in Germany (BRIDGE) Consortium and UNC-CH was assessed. FGFR status was defined by a prespecified panel of FGFR2/3 mutations and fusions. Overall survival (OS) was analyzed using Kaplan-Meier estimates and Cox proportional hazards models. Multivariate analyses were performed using potential prognostic covariates (sex, age, baseline tumor stage, urothelial histology, smoking history, primary tumor location, and ECOG) in a Cox regression model for OS to assess their impact on the effect of FGFR alterations. Results: Median OS for FGFR+ pts (n=28) who received any line of anti-PD-(L)1 therapy was 9.5 mo vs 7.5 mo for FGFR− pts (n=139) (HR: 1.03, 95% CI: 0.60-1.76, p=0.93). Median OS for pts treated with first-line anti-PD-(L)1 was 5.42 mo in FGFR+ pts (n=10) and was not reached for FGFR− pts (n=31) (HR: 2.06, 95% CI: 0.68-6.24, p=0.19); median OS in second-line anti-PD-(L)1 was 6.5 mo (FGFR+; n=14) vs 5.7 mo (FGFR−; n=86) (HR: 0.89, 95% CI: 0.44-1.81, p=0.74). The multivariate analyses showed a significant trend of poorer OS in FGFR+ pts with first-line anti-PD-(L)1 (HR: 10.42, 95% CI: 1.45-74.97, p=0.02); wide CI may be attributed to small sample size for some categories in several covariates. Conclusions: Treatment with first-line anti-PD-(L)1 in FGFR+ pts may be associated with poorer OS outcomes in FGFR+ pts; however, this trend was not observed in FGFR+ pts treated with any line and second-line anti-PD-(L)1. Investigation of the predictive value of FGFR alterations to immunotherapy outcomes in larger real-world pt datasets is warranted.

Incidence and prediction of checkpoint inhibitor immune-related nephrotoxicity

91

Background: Immune checkpoint inhibitors (ICIs), through inhibition of self-tolerance, have the potential to cause immune-related adverse events that can affect any organ, including the kidneys. Our study aimed to better characterize the incidence of and predictive characteristics for immune-related nephrotoxicity. Methods: All patients at the University of North Carolina (UNC) who received ICIs between April 2014 and December 2018 for any malignancy were identified. Patients on dialysis or those who received concurrent platinum-based chemotherapy were excluded. Any patient who subsequently had a clinically significant acute kidney injury (AKI), defined as a doubling or more of baseline creatinine, was included for analysis. A retrospective chart review was performed to determine the cause of AKI. Any uncertain cases were reviewed by two nephrologists for expert consensus (R.R. and V.D.). Results: 1766 patients received an ICI during the study period. 123 (7%) patients had AKI within one year of the first ICI dose. 14 were due to immune-related nephrotoxicity (11% of patients with AKI and 0.8% of all ICI patients). Pre-existing autoimmune disease was more likely in patients with immune-related nephrotoxicity than in those with non-immune AKI (14% vs 3%, p = 0.04). Similarly, concurrent or prior other immune-related adverse events were more common in patients with immune-related AKI (57% vs 6%, p = 0.01). Patients with immune-related AKI were more likely to see a nephrologist (57% vs 23%, p = 0.007) and had a more profound increase in creatinine from baseline (median 2.6 vs 1.6, p = 0.02). Age, sex, urinalysis findings, and primary tumor type were not associated with increased risk. Conclusions: The true incidence of ICI related nephrotoxicity is difficult to ascertain due to the many confounders that contribute to AKI in this population. Severe immune-related nephrotoxicity is rare, but patients with preexisting autoimmune disease or history of immune-related adverse events are at increased risk.

RNAseq and DNA whole-exome sequence analysis reveal novel response signatures to IO treatment in muscle invasive bladder cancer (MIBC) patients

4558

Background: Objective: To examine in a cohort of anti-PD-(L)1 immune checkpoint inhibitors (ICP) treated urothelial cancer patients a strategy combining treatment outcomes with molecular alterations, pathways, and immune/tumor microenvironment features to determine potential responder and rapid-progression signatures. Methods: De-identified clinical history and treatment outcomes were collected on 109 MIBC patients treated with ICP agents. Archived FFPE samples from these patients were obtained and processed for mRNAseq, exome-seq, tumor mutation burden (TMB), microsatellite instability (MSI) and mutation panel testing. Comprehensive tumor/immune profiling is being analyzed in the context of ICP treatments and RECIST 1.1 outcomes. A 60 gene MIBC 4-typer expression subtyper and other response associated predictors are used to stratify and identify positive/negative ICP response indicators. Results: 109 patients were identified (median age 75, 64% male, 78% white, 17% black). 74% of patients had received prior platinum-based chemotherapy, and 12% had received 2 or more prior lines of therapy. At initiation of ICP, 28% of patients had hemoglobin < 10, 30% had liver metastases, and 59% had ECOG performance status > 0. Mutation analysis of the first 66 patients showed TP53 (n = 34, 52%), FGFR (n = 17, 26%), CDKN2A (n = 13, 20%) and RB1 (n = 12, 18%) as the top alterations. No patients (0/8) with known pathogenic mutations in FGFR3 (S249C and TACC3-fusion) responded to ICP. Of patients with T2 staging prior to ICP (37/66), overall survival was markedly shorter (2.7 years) in those possessing FGFR3 mutations (n = 6/37) compared to that for FGFR3 WT patients (5.7 years, n = 31/37; p = 0.045). Further analyses of molecular features relative to treatment outcomes are ongoing to characterize response signatures. Conclusions: Our preliminary cohort of patients with pathogenic FGFR3 alterations showed 0% favorable response to ICP. We are expanding on this observation with further comprehensive molecular analyses and retrospective treatments/outcomes data. We anticipate identifying expression signatures that reflect ICP patient responder/non-responder signatures that may aid in future therapy decisions.