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PURPOSE Cediranib, a pan-vascular endothelial growth factor receptor inhibitor, suppresses expression of homologous recombination repair (HRR) genes and increases sensitivity to poly-(ADP-ribose) polymerase inhibition in preclinical models. We investigated whether cediranib combined with olaparib improves the clinical outcomes of patients with prostate cancer. METHODS Patients with progressive metastatic castration-resistant prostate cancer (mCRPC) were randomly assigned 1:1 to arm A: cediranib 30 mg once daily plus olaparib 200 mg twice daily or arm B: olaparib 300 mg twice daily alone. The primary end point was radiographic progression-free survival (rPFS) in the intention-to-treat patients. The secondary end points were rPFS in patients with HRR-deficient and HRR-proficient mCRPC. RESULTS In the intention-to-treat set of 90 patients, median rPFS was 8.5 (95% CI, 5.4 to 12.0) and 4.0 (95% CI, 3.2 to 8.5) months in arms A and B, respectively. Cediranib/olaparib significantly improved rPFS versus olaparib alone (hazard ratio [HR], 0.617; 95% CI, 0.392 to 0.969; P = .0359). Descriptive analyses showed a median rPFS of 10.6 (95% CI, 5.9 to not assessed [NA]) and 3.8 (95% CI, 2.33 to NA) months (HR, 0.64; 95% CI, 0.272 to 1.504) among patients with HRR-deficient mCRPC, and 13.8 (95% CI, 3.3 to NA) and 11.3 (95% CI, 3.8 to NA) months (HR, 0.98; 95% CI, 0.321 to 2.988) among patients with BRCA2-mutated mCRPC in arms A and B, respectively. The incidence of grades 3-4 adverse events was 61% and 18% in arms A and B, respectively. CONCLUSION Cediranib combined with olaparib improved rPFS compared with olaparib alone in men with mCRPC. This combination was associated with an increased incidence of grades 3-4 adverse events. BRCA2-mutated subgroups treated with olaparib with or without cediranib were associated with a numerically longer median rPFS.

A lower baseline neutrophil-to-eosinophil ratio (NER) has been associated with improved responses to immune checkpoint inhibitors (ICI)-treated metastatic renal cell carcinoma (mRCC). This study investigated the decrease in NER at week 6 after ipilimumab/nivolumab (ipi/nivo) initiation and treatment responses in mRCC. A retrospective study of ipi/nivo-treated mRCC at two US academic cancer centers was conducted. A landmark analysis at week 6 was performed to assess the association between the change in NER and clinical responses (progression-free survival (PFS)/overall survival (OS)). Week 6 NER was modeled as a continuous variable, after log transformation (Ln NER), and a categorical variable by percent change. There were 150 mRCC patients included: 78% had clear cell histology, and 78% were IMDC intermediate/poor risk. In multivariable regression analysis, every decrease of 1 unit of Ln NER at week 6 was associated with improved PFS (adjusted hazard ratio (AHR): 0.78, p-value:0.005) and OS (AHR: 0.67, p-value: 0.002). When NER was modeled by percent change, decreased NER > 50% was associated with improved PFS (AHR: 0.55, p-value: 0.03) and OS (AHR: 0.37, p-value: 0.02). The decrease in week 6 NER was associated with improved PFS/OS in ipi/nivo-treated mRCC. Prospective studies are warranted to validate NER change as a biomarker to predict ICI responses.

Purpose Liver metastasis in genitourinary (GU) malignancies signifies a poor prognosis and has a negative effect on patient survival. Selected patients with metastatic GU malignancies have liver-dominant disease. Liver-directed therapies (LDT) with conventional transarterial chemoembolization (cTACE) and transarterial radioembolization (TARE) have been well studied in primary liver cancer and metastatic hepatic disease and proven to be safe and efficacious in selected populations. Materials and Methods From 2005 to 2016, 32 patients with metastatic renal, bladder, or prostate cancer and liver-dominant metastases treated with cTACE or TARE were identified. Retrospective review of patient records was performed to assess baseline characteristics, imaging treatment response, survival, and treatment toxicity. Results The median survival from diagnosis of liver metastasis was 37 months in renal cell carcinoma (RCC), 8 months in transitional cell carcinoma (TCC), and 6 months in prostate carcinoma. 90% of patients with RCC maintained their ECOG performance status one-month post-treatment, as did 64% of the bladder and prostate groups. LDT was well tolerated for the most part. Conclusion LDT in patients with metastatic GU cancer is well tolerated and can lead to improved survival for some patients. Further studies are necessary to determine which patients may benefit the most.

PURPOSE Platinum-based chemotherapy for first-line treatment of metastatic urothelial cancer is typically administered for a fixed duration followed by observation until progression. “Switch maintenance” therapy with PD-1 blockade at the time of chemotherapy cessation may be attractive for mechanistic and pragmatic reasons. PATIENTS AND METHODS Patients with metastatic urothelial cancer achieving at least stable disease on first-line platinum-based chemotherapy were enrolled. Patients were randomly assigned double-blind 1:1 to switch maintenance pembrolizumab 200 mg intravenously once every 3 weeks versus placebo for up to 24 months. Patients with disease progression on placebo could cross over to pembrolizumab. The primary objective was to determine the progression-free survival. Secondary objectives included determining overall survival as well as treatment outcomes according to PD-L1 combined positive score (CPS). RESULTS Between December 2015 and November 2018, 108 patients were randomly assigned to pembrolizumab (n = 55) or placebo (n = 53). The objective response rate was 23% with pembrolizumab and 10% with placebo. Treatment-emergent grade 3-4 adverse events occurred in 59% receiving pembrolizumab and 38% of patients receiving placebo. Progression-free survival was significantly longer with maintenance pembrolizumab versus placebo (5.4 months [95% CI, 3.1 to 7.3 months] v 3.0 months [95% CI; 2.7 to 5.5 months]; hazard ratio, 0.65; log-rank P = .04; maximum efficiency robust test P = .039). Median overall survival was 22 months (95% CI, 12.9 months to not reached) with pembrolizumab and 18.7 months (95% CI, 11.4 months to not reached) with placebo. There was no significant interaction between PD-L1 CPS ≥ 10 and treatment arm for progression-free survival or overall survival. CONCLUSION Switch maintenance pembrolizumab leads to additional objective responses in patients achieving at least stable disease with first-line platinum-based chemotherapy and prolongs progression-free survival in patients with metastatic urothelial cancer.

518 Background: Pembro is standard of care for pts with mUC who progress after 1L PT therapy but only ~21% of pts respond, highlighting an unmet need (Bellmunt, et al. NEJM. 2017). SG is an antibody-drug conjugate composed of an anti-Trop-2 antibody coupled to SN-38 via a hydrolyzable linker. In Cohort 1 of the TROPHY-U-01 study, SG demonstrated a 27% objective response rate (ORR) with manageable safety in 113 pts with locally advanced or mUC who previously received PT and a checkpoint inhibitor (CPI; Tagawa, et al. J Clin Oncol. 2021), leading to accelerated FDA approval in this pt population. Preliminary results of the phase 2 TROPHY-U-01 Cohort 3 study showed that SG plus Pembro demonstrated a high ORR (34%) as a 2L therapy in 41 CPI-naive pts with mUC who progressed after PT (Grivas et al. J Clin Oncol. 2021). Here we present the primary analysis of Cohort 3. Methods: Cohort 3 pts (≥18 y) had progression of mUC following PT in the metastatic setting or following ≤12 mo of PT in the (neo)adjuvant setting and ECOG PS 0-1. Pts received 10 mg/kg of SG on D1 and D8 and 200 mg of Pembro on D1 of a 21-D cycle for ≤2 y. The primary endpoint was ORR [complete response (CR) + partial response (PR)] per central review by RECIST 1.1. Secondary endpoints include clinical benefit rate [CBR; CR + PR + stable disease for at least 6 mo], duration of response (DOR) and progression-free survival (PFS) per central review; and safety. Target enrollment was approximately 41 pts based on a Simon two-stage design for 90% power at one-sided α of 0.05 to demonstrate 21% improvement in ORR, with a null hypothesis of historical ORR ≤20% and an alternate hypothesis of ORR ≥41%. Results: As of July 26, 2022, median follow-up was 12.5 mo (range, 0.9-24.6) for treated pts (N=41); median age, 67 y (range, 46-86), 83% male, 61% ECOG PS 1, 76% ≥1 Bellmunt risk factors, and 78% visceral metastases (29% liver). Median duration of last prior anti-cancer therapy was 2.7 mo (range, 0-13). Per central review, ORR was 41% (95% CI, 26.3-57.9; 20% CR); CBR was 46% (95% CI, 30.7-62.6); median DOR was 11.1 mo (95% CI, 4.8-NE [not estimable]; n=17); and median PFS was 5.3 mo (95% CI, 3.4-10.2). Median time to response was 1.4 mo (95% CI, 1.3-2.7) and median OS was 12.7 mo (95% CI, 10.7-NE). Grade ≥3 treatment-related adverse events (TRAEs) occurred in 61% of pts; most common Grade ≥3 TRAEs were neutropenia (37%; 10% febrile neutropenia), leukopenia (20%), and diarrhea (20%). TRAEs led to a 15% discontinuation rate. Systemic steroid and G-CSF use were both 34%. No treatment-related death occurred. Conclusions: SG plus Pembro demonstrated a high ORR and CBR with a manageable safety profile in 2L mUC in CPI-naive pts who progressed after PT-based therapy. No new safety signals were observed with the combination. These data support further evaluation of SG plus CPI in mUC. Clinical trial information: NCT03547973 .

514 Background: EV is FDA-approved in pts with aUC and ≥1 prior therapy line. Data from EV-103 trial indicate robust response to first-line EV/pembrolizumab, suggesting potentially at least additive treatment effect with EV/ICI combination. Given the long half-life of ICIs, pts who start EV treatment immediately after ICI may potentially derive benefit from that therapy sequence. We hypothesized that the last systemic therapy prior to EV would impact outcomes, as pts treated with ICI immediately prior to EV would have superior outcomes relative to pts treated with chemotherapy (chemo). Methods: UNITE is a retrospective study of pts treated with EV at 16 US sites. Pt characteristics and outcomes were abstracted from EMR review at each site. Observed response was determined by investigators for evaluable pts with scans following ≥1 EV dose. Pts treated with EV monotherapy were divided into two groups based on whether they received chemo or ICI as the line of therapy immediately prior to EV, regardless of other therapy received. Chi-squared test was used to assess differences in pt characteristics and ORR while log-rank tests were used for OS and PFS measured from EV start. Results: Among 325 pts treated with EV monotherapy, 247 had chemo or ICI as immediate prior treatment, with 186 pts receiving ICI (Group A) and 61 pts receiving platinum-based chemo (Group B). In 247-pt cohort, ORR to EV was 52% and mPFS and mOS were 6 and 13 mos. Group B pts were younger, had more bone mets and higher Bellmunt risk factors, but were otherwise similar to Group A (Table). Most pts had both prior chemo and ICI in both group A (58%) and group B (84%). Group A pts had shorter time from last treatment (median 1.2 vs 3.2 mo, p

450 Background: EV, an antibody-drug conjugate (ADC) targeting Nectin-4, is used widely in treatment-refractory aUC, but limited data are available on biomarkers predictive of EV outcomes. We investigated potential biomarkers of response to EV in a pt cohort in the UNITE dataset. Methods: We included the retrospective UNITE study pts from 16 sites, with available next generation sequencing using institutional or commercial platforms, treated with EV alone outside clinical trials. Observed response (ORR) was determined by investigators for evaluable pts with scans after ≥1 dose of EV. Assessed molecular biomarkers included tumor mutation burden (TMB), PD-L1 status, somatic alterations (alts) in ≥ 10% of pts ( TERTp, TP53, ARID1A, CDKN2A, CDKN2B, FGFR3, ERBB2, CCND1, KDM6A, MTAP, PIK3CA, RB1, TSC1) and presence of ≥1 DNA damage response mutations ( ATM, BARD1, BRCA1, BRCA2, CDK12, CHEK2, PALB2, PPP2R2A, or RAD51B). ORRs were compared using Chi-squared test, while median progression-free and overall survival (mPFS, mOS) from EV start were compared with log-rank test and Cox proportional hazards in pts with and without biomarker presence. Results: A total of 170 pts had outcomes and NGS data available. Median age was 70, 133 (78%) were men, 144 (85%) Caucasian, 110 (65%) with pure urothelial histology, 118 (69%) with primary bladder tumor, and 116 (68%) had ≥ 2 lines of therapy before EV. For all pts, ORR 47%, mPFS 6 mos, mOS 12 mos. ORRs were higher in pts with ERBB2 (67% vs 44%; p = 0.05) and TSC1 (68% vs 25%; p=0.04) alts vs wild-type. Shorter mPFS was noted in pts with CDKN2A, CDKN2B, and MTAP alts, and longer mOS in pts with high TMB (table). Conclusions: This large, multi-site, retrospective cohort of pts with aUC identified several potential biomarkers associated with differential outcomes to EV. These findings, upon external validation, may help inform clinical decision making and potential therapy sequencing with available ADCs. Limitations include retrospective nature, pt selection, and confounding biases. [Table: see text]

Background The identification of biomarkers to select patients with metastatic renal cell carcinoma (mRCC) most likely to respond to combination immunotherapy (IO) is needed. We sought to investigate an association of the baseline neutrophil-to-eosinophil ratio (NER) with outcomes to nivolumab plus ipilimumab for patients with mRCC. Methods We performed a retrospective review of patients with clear cell mRCC treated with nivolumab plus ipilimumab from Vanderbilt-Ingram Cancer Center and Duke Cancer Institute. Patients with prior receipt of immunotherapy and those without available baseline complete blood count with differential were excluded. Patients were divided into groups by the median baseline NER and analyzed for overall survival (OS), progression free survival (PFS), and objective response rate (ORR). Patients were also divided by median baseline neutrophil-to-lymphocyte ratio (NLR) and analyzed for clinical outcome. Further analyses of patients above/below the median NER and NLR were performed in subgroups of IMDC intermediate/poor risk, IMDC favorable risk, and treatment naïve patients. Results A total of 110 patients were included: median age was 61 years and 75% were treatment naïve. The median NER (mNER) at baseline was 26.4. The ORR was 40% for patients with mNER (OR 2.39, p = 0.04). The median PFS for patients with mNER (HR 0.50, p mNER (HR 0.31, p p = 0.02), PFS and ORR did not differ compared with patients in the >mNLR group. Conclusions A lower baseline NER was associated with improved clinical outcomes (PFS, OS, and ORR) in patients with mRCC treated with nivolumab plus ipilimumab, and prospective validation of the baseline NER as a predictive biomarker for response to immunotherapy-based combinations in mRCC is warranted.

Enfortumab vedotin (EV) is a novel antibody-drug conjugate approved for advanced urothelial cancer (aUC) refractory to prior therapy. In the Urothelial Cancer Network to Investigate Therapeutic Experiences (UNITE) study, the authors looked at the experience with EV in patient subsets of interest for which activity had not been well defined in clinical trials.UNITE was a retrospective study of patients with aUC treated with recently approved agents. This initial analysis focused on patients treated with EV. Patient data were abstracted from chart reviews by investigators at each site. The observed response rate (ORR) was investigator-assessed for patients with at least 1 post-baseline scan or clear evidence of clinical progression. ORRs were compared across subsets of interest for patients treated with EV monotherapy.The initial UNITE analysis included 304 patients from 16 institutions; 260 of these patients were treated with EV monotherapy and included in the analyses. In the monotherapy cohort, the ORR was 52%, and it was40% in all reported subsets of interest, including patients with comorbidities previously excluded from clinical trials (baseline renal impairment, diabetes, and neuropathy) and patients with fibroblast growth factor receptor 3 (FGFR3) alterations. Progression-free survival and overall survival were 6.8 and 14.4 months, respectively. Patients with a pure urothelial histology had a higher ORR than patients with a variant histology component (58% vs 42%; P = .06).In a large retrospective cohort, responses to EV monotherapy were consistent with data previously reported in clinical trials and were also observed in various patient subsets, including patients with variant histology, patients with FGFR3 alterations, and patients previously excluded from clinical trials with an estimated glomerular filtration rate30 mL/min and significant comorbidities.Enfortumab vedotin, approved by the Food and Drug Administration in 2019, is an important new drug for the treatment of patients with advanced bladder cancer. This study looks at the effectiveness of enfortumab vedotin as it has been used at multiple centers since approval, and focuses on important patient populations previously excluded from clinical trials. These populations include patients with decreased kidney function, diabetes, and important mutations. Enfortumab vedotin is effective for treating these patients. Previously reported clinical trial data have been replicated in this real-world setting, and support the use of this drug in broader patient populations.

e18815 Background: Disparities in diagnosis, treatment, and outcomes for bladder cancer in underserved patient populations persist in the United States. High out-of-pocket costs can prevent patients from seeking or continuing treatment, which can worsen existing disparities in care. The Association of Community Cancer Centers (ACCC) conducted a claims analysis of Medicare beneficiaries diagnosed with bladder cancer to assess differences in healthcare utilization and costs and to inform future provider education initiatives. Methods: ACCC convened an expert steering committee of multidisciplinary specialists and patient advocates to guide the development of the claims analysis methodology and code sets used to identify study cohorts and model variables. Using the CMS Medicare 100% Innovator Administrative Claims Data Set, incident patients were defined as those newly diagnosed in 2018 using a 24-month lookback to confirm no prior bladder cancer diagnosis. Claims for incident patients incurred in the time-period between 24 months prior to and 24 months following diagnosis date were analyzed to generate descriptive summaries of cohorts by severity of disease at diagnosis. Classification is defined by treatment observed within 6 months of diagnosis: No treatment, Early Stage-treated (intravesical chemotherapy), and Late-stage (one or more claims of non-intravesical systemic therapy, radiation therapy, or major bladder surgery). Results: 4,356 incident patients were identified: average age 77.7, 71% male, 56% no treatment, 15% early-stage treated, 28% late-stage. Patients diagnosed at late-stage incur 128% more allowed costs (total amount paid by Medicare and patients) on all-cause healthcare in the first year after diagnosis than early-stage patients who receive treatment ($76,483 vs $33,530) and 101% higher cumulative costs two years following diagnosis ($112,178 vs $55,814). Patients diagnosed at late-stage incur 90% more out-of-pocket costs (copays, coinsurance, deductibles) in the first year following diagnosis than early-stage treated patients ($9,970 vs $5,225) and 81% higher cumulative out-of-pocket costs two years following diagnosis ($15,145 vs $8,390). For both early- and late-stage patients, the month of diagnosis is the most expensive. 53% of all costs incurred in the month of diagnosis are for cystoscopy/TURBT procedures. Elevated costs persist at levels higher than pre-diagnosis levels for at least 20 months. Among late-stage patients, treatments (surgery, radiation therapy, and systemic therapy) sum to 34% of all costs incurred in 6 months following diagnosis. Conclusions: Patients diagnosed with late-stage bladder cancer experience higher financial burden and need more resource-intensive services than those diagnosed at an earlier stage. Earlier diagnosis of bladder cancer is needed to improve patient outcomes and reduce financial burden.

e17053 Background: 18F-DCFPyL (piflufolastat F 18) is a PSMA-targeted agent FDA-approved for PET imaging in men with prostate cancer. Given the recent availability for clinical use, we sought to evaluate the impact and potential changes in management after the incorporation of 18F-DCFPyL (PyL) PET/CT at an academic medical center. Methods: We reviewed the first 100 PyL PET/CT scans performed at the Vanderbilt-Ingram Cancer Center for men with prostate adenocarcinoma. Patient demographics, treatment history, and prior imaging results were recorded, along with PyL PET results, most recent PSA, and clinical management plans. Management changes were designated as change in systemic therapy, radiation, or surgery and were determined by two independent reviewers with a third reviewer for any discordant cases. Results: There were 100 men included with PyL PET scans dating from 9/1/21 to 12/31/21. The median age was 69 years, 76% of patients were white and 13% were black. The median Gleason sum at diagnosis was 7 (4+3), 55% of men had prior prostatectomy, and 38% had prior radiation to the prostate/pelvis. The median PSA prior to PyL PET scan was 1.86 (IQR 0.53-9.95 ng/mL), 32% of men had previous ADT exposure, and 15% were on ADT at the time of PyL PET scan. The clinical setting prior to PyL PET scan was initial staging 22%, biochemical recurrence 59%, m1HSPC 14%, m0CRPC 2%, and m1CRPC 3%. There were 16 patients who had a prior 18F-fluciclovine within six months of PyL PET; of these 69% (11/16) had additional disease on PyL PET not previously identified. Activity in lymph nodes was observed in 48%, bone 37%, visceral sites 3%, prostate/prostate bed 46%, and 15% had no PSMA-avid disease. Clinical staging was altered after the PyL PET scan in 55% of patients, with the most common change being from BCR to m1HSPC (40/55). Clinical management was altered in 59% of cases: systemic therapy 38%, radiation planning 46%, and surgical planning 6% (Table). Conclusions: Clinical management was affected in 59% of cases after implementation of PyL PET in this retrospective, single center review. Given the rapid adoption of PSMA-targeted PET imaging agents, further studies are needed to evaluate the clinical impact of subsequent changes to management planning, as well as to develop multidisciplinary consensus statements and protocols to guide management.[Table: see text]

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]

4541 Background: Immunotherapy (IO) has become the standard of care in patients with metastatic renal cell carcinoma (mRCC), yet clinical biomarkers of outcome remain elusive. Preclinical and clinical studies have demonstrated that a lower tumor volume burden is associated with better response to IO in melanoma and lung cancer. Methods: Retrospective chart review of mRCC patients treated with Immunotherapy/Immunotherapy or Immunotherapy/Tyrosine kinase inhibitors (TKI) combinations at Vanderbilt Ingram Cancer Center was conducted. Baseline target tumor lesions including primary kidney tumors and treatment response were assessed by RECIST 1.1 criteria. The association between baseline tumor burden and outcomes of interest [progression-free survival (PFS) and overall survival (OS)] were assessed with multivariable Cox regression model. Results: 79 patients with mRCC were included in the cohort. The median age was 64, 80% were male, 82% had clear cell histology, and 73% were IMDC intermediate/poor risk group. 53% received IO/IO and 39% received IO/TKI. 71% had prior nephrectomy and 14% had prior systemic therapy. The median baseline tumor burden was 87 mm (range: 16-363 mm). After adjusting for age, gender, histology, prior nephrectomy/systemic therapy and IMDC risk, baseline tumor burden was not associated with either PFS (p-value: 0.42) or OS (p-value: 0.99). At the initial follow-up scan (median time of 3.1 months from treatment initiation) 22 (28%) patients had an objective response and 41 (52%) patients had stable disease. Among patients with tumor shrinkage, every 10% decrease seen in the sum of the target lesions was associated with improved PFS (AHR: 0.77, 95%CI: 0.63-0.94, p-value:0.009) and OS (AHR: 0.62, 95%CI: 0.42-0.93, p-value:0.02). Conclusions: While baseline tumor burden volume was not associated with clinical outcome to immunotherapy-based therapy in patients with metastatic RCC; however, the degree of early tumor shrinkage was significantly associated with better outcomes. Large tumor burden does not preclude response and good outcome to immunotherapies.

4527 Background: Low baseline NER has been associated with improved response to immunotherapy in mRCC (PMID:34732251). The current study aimed to investigate the early decline of NER at week 6 after ipilimumab/nivolumab (ipi/nivo) initiation and treatment responses in mRCC. Methods: Retrospective chart review of ipi/nivo-treated mRCC patients at Vanderbilt-Ingram Cancer Center and Duke Cancer Institute was conducted. Landmark analysis at week 6 after ipi/nivo initiation was performed to assess the association between change in NER and clinical responses [progression-free survival (PFS)/overall survival (OS)]. Results: There were 150 mRCC patients included in the analysis: 78% had clear cell histology, 78% were IMDC intermediate/poor risk, and 74% were male. The median follow-up time was 11.9 months. After ipi/nivo initiation, the median NER decreased from 23.8 (interquartile range: 15.0-57.1) at baseline to 19.8 (10.6-40.8) at week 6; 102 (68%) patients had decreased NER. The NER at week 6 was grouped by percent change (≥ 50% decrease vs

BACKGROUND Ensuring representative data accrual in clinical trials is important to safeguard the generalizability of results and to minimize disparities in care. This study's goal was to evaluate differences in gender representation in trials leading to US Food and Drug Administration (FDA) cancer drug approvals. METHODS An observational study was conducted from January 2014 to April 2019 using PubMed and the National Institutes of Health trials registry for primary trial reports. The National Cancer Institute's Surveillance, Epidemiology, and End Results program and US Census were consulted for national cancer incidence. The outcome was an enrollment incidence disparity (EID), which was calculated as the difference between male and female trial enrollment and national incidence, with positive values representing male overrepresentation. RESULTS There were 149 clinical trials with 59,988 participants-60.3% and 39.7% were male and female, respectively-leading to 127 oncology drug approvals. The US incidence rates were 55.4% for men versus 44.6% for women. Gender representation varied by specific tumor type. Most notably, women were underrepresented in thyroid cancer (EID, +27.4%), whereas men were underrepresented in soft tissue cancer (EID, -26.1%). Overall, women were underrepresented when compared with expected incidence (EID, +4.9%; 42% of trials). CONCLUSIONS For many specific tumor types, women are underrepresented in clinical trials leading to FDA oncology drug approvals. It is critical to better align clinical trial cohort demographics and the populations to which these data will be extrapolated. LAY SUMMARY This study assesses whether gender disparities exist in clinical trials leading to US Food and Drug Administration (FDA) cancer drug approvals. From January 2014 to April 2019, 149 clinical trials leading to FDA oncology drug approvals showed 60.3% and 39.7% of the enrollees were male and female, respectively. Gender representation varied by specific tumor when compared with the expected incidence rate of cancer in the United States, although women were more often underrepresented. Increased efforts are needed with regard to ensuring equitable representation in oncology clinical trials.

BACKGROUND Surgery remains the frontline therapy for patients with localized clear cell renal cell carcinoma (ccRCC); however, 20%–40% recur. Angiogenesis inhibitors have improved survival in metastatic patients and may result in responses in the neoadjuvant setting. The impact of these agents on the tumor genetic heterogeneity or the immune milieu is largely unknown. This phase II study was designed to evaluate safety, response, and effect on tumor tissue of neoadjuvant pazopanib. METHODS ccRCC patients with localized disease received pazopanib (800 mg daily; median 8 weeks), followed by nephrectomy. Five tumors were examined for mutations by whole exome sequencing from samples collected before therapy and at nephrectomy. These samples underwent RNA sequencing; 17 samples were available for posttreatment assessment. RESULTS Twenty-one patients were enrolled. The overall response rate was 8 of 21 (38%). No patients with progressive disease. At 1-year, response-free survival and overall survival was 83% and 89%, respectively. The most frequent grade 3 toxicity was hypertension (33%, 7 of 21). Sequencing revealed strong concordance between pre- and posttreatment samples within individual tumors, suggesting tumors harbor stable core profiles. However, a reduction in private mutations followed treatment, suggesting a selective process favoring enrichment of driver mutations. CONCLUSION Neoadjuvant pazopanib is safe and active in ccRCC. Future genomic analyses may enable the segregation of driver and passenger mutations. Furthermore, tumor infiltrating immune cells persist during therapy, suggesting that pazopanib can be combined with immune checkpoint inhibitors without dampening the immune response. FUNDING Support was provided by Novartis and GlaxoSmithKline as part of an investigator-initiated study., Neoadjuvant treatment with pazopanib results in tumor response in clear cell renal cell carcinoma, and lends insight into genetic and immunological effects of these inhibitors.

PURPOSE To provide guidance to clinicians regarding the use of systemic therapy for melanoma. METHODS ASCO convened an Expert Panel and conducted a systematic review of the literature. RESULTS A systematic review, one meta-analysis, and 34 additional randomized trials were identified. The published studies included a wide range of systemic therapies in cutaneous and noncutaneous melanoma. RECOMMENDATIONS In the adjuvant setting, nivolumab or pembrolizumab should be offered to patients with resected stage IIIA/B/C/D BRAF wild-type cutaneous melanoma, while either of those two agents or the combination of dabrafenib and trametinib should be offered in BRAF-mutant disease. No recommendation could be made for or against the use of neoadjuvant therapy in cutaneous melanoma. In the unresectable/metastatic setting, ipilimumab plus nivolumab, nivolumab alone, or pembrolizumab alone should be offered to patients with BRAF wild-type cutaneous melanoma, while those three regimens or combination BRAF/MEK inhibitor therapy with dabrafenib/trametinib, encorafenib/binimetinib, or vemurafenib/cobimetinib should be offered in BRAF-mutant disease. Patients with mucosal melanoma may be offered the same therapies recommended for cutaneous melanoma. No recommendation could be made for or against specific therapy for uveal melanoma. Additional information is available at www.asco.org/melanoma-guidelines .

Purpose This guideline provides recommendations on the management of adults after head and neck cancer (HNC) treatment, focusing on surveillance and screening for recurrence or second primary cancers, assessment and management of long-term and late effects, health promotion, care coordination, and practice implications. Methods ASCO has a policy and set of procedures for endorsing clinical practice guidelines that have been developed by other professional organizations. The American Cancer Society (ACS) HNC Survivorship Care Guideline was reviewed for developmental rigor by methodologists. An ASCO Expert Panel reviewed the content and recommendations, offering modifications and/or qualifying statements when deemed necessary. Results The ASCO Expert Panel determined that the ACS HNC Survivorship Care Guideline, published in 2016, is clear, thorough, clinically practical, and helpful, despite the limited availability of high-quality evidence to support many of the recommendations. ASCO endorsed the ACS HNC Survivorship Care Guideline, adding qualifying statements aimed at promoting team-based, multispecialty, multidisciplinary, collaborative head and neck survivorship care. Recommendations The ASCO Expert Panel emphasized that caring for HNC survivors requires a team-based approach that includes primary care clinicians, oncology specialists, otolaryngologists, dentists, and other allied professionals. The HNC treatment team should educate the primary care clinicians and patients about the type(s) of treatment received, the likelihood of potential recurrence, and the potential late and long-term complications. Primary care clinicians should recognize symptoms of recurrence and coordinate a prompt evaluation. They should also be prepared to manage late effects either directly or by referral to appropriate specialists. Health promotion is critical, particularly regarding tobacco cessation and dental care. Additional information is available at www.asco.org/HNC-Survivorship-endorsement and www.asco.org/guidelineswiki .

Summary Background Checkpoint inhibitor therapy is a standard of care for patients with metastatic renal cell carcinoma. Treatment options after checkpoint inhibitor therapy include vascular endothelial growth factor receptor (VEGF-R) tyrosine kinase inhibitors, although no prospective data regarding their use in this setting exist. Axitinib is a VEGF-R inhibitor with clinical data supporting increased activity with dose titration. We aimed to investigate the activity of dose titrated axitinib in patients with metastatic renal cell carcinoma who were previously treated with checkpoint inhibitor. Methods We did a multicentre, phase 2 trial of axitinib given on an individualised dosing algorithm. Patients at least 18 years of age with histologically or cytologically confirmed locally recurrent or metastatic renal cell carcinoma with clear cell histology, a Karnofsky Performance Status of 70% or more, and measurable disease who received checkpoint inhibitor therapy as the most recent treatment were eligible. There was no limit on number of previous therapies received. Patients received oral axitinib at a starting dose of 5 mg twice daily with dose titration every 14 days in 1 mg increments (ie, 5 mg twice daily to 6 mg twice daily, up to 10 mg twice daily maximum dose) if there was no axitinib-related grade 2 or higher mucositis, diarrhoea, hand-foot syndrome, or fatigue. If one or more of these grade 2 adverse events occurred, axitinib was withheld for 3 days before the same dose was resumed. Dose reductions were made if recurrent grade 2 adverse events despite treatment breaks or grade 3–4 adverse events occurred. The primary outcome was progression-free survival. Analyses were done per protocol in all patients who received at least one dose of axitinib. Recruitment has been completed and the trial is ongoing. This trial is registered with ClincalTrials.gov , number NCT02579811 . Findings Between Jan 5, 2016 and Feb 21, 2018, 40 patients were enrolled and received at least one dose of study treatment. With a median follow-up of 8·7 months (IQR 3·7–14·2), the median progression-free survival was 8·8 months (95% CI 5·7–16·6). Fatigue (83%) and hypertension (75%) were the most common all-grade adverse events. The most common grade 3 adverse event was hypertension (24 patients [60%]). There was one (3%) grade 4 adverse event (elevated lipase) and no treatment-related deaths occurred. Serious adverse events that were likely related to therapy occurred in eight (20%) patients; the most common were dehydration (n=4) and diarrhoea (n=2). Interpretation Individualised axitinib dosing in patients with metastatic renal cell inoma previously treated with checkpoint inhibitors did not meet the prespecified threshold for progression free survival, but these data show that this individualised titration scheme is feasible and has robust clinical activity. These prospective results warrant consideration of axitinib in this setting. Funding Pfizer.

4501 Background: Dysregulated metabolism is a hallmark of RCC, driven by overexpression of glutaminase (GLS), a key enzyme of glutamine metabolism. Telaglenastat (Tela) is an investigational, first-in-class, selective, oral GLS inhibitor that blocks glutamine utilization and critical downstream pathways. Preclinically, Tela synergized w/ cabozantinib (Cabo), a VEGFR2/MET/AXL inhibitor, against RCC tumors. In a Ph 1 study cohort, Tela+Cabo showed encouraging safety/efficacy as 2L+ therapy for mRCC. This trial compared Tela+Cabo vs Pbo+Cabo in previously treated pts w/ clear-cell mRCC (NCT03428217). Methods: Eligible pts had 1-2 prior lines of systemic therapy for mRCC, including ≥1 anti-angiogenic therapy or nivolumab + ipilimumab (nivo/ipi), KPS ≥70%, measurable disease (RECIST 1.1), no prior Cabo or other MET inhibitor. Pts were randomized 1:1 to receive Cabo (60 mg PO QD) with either Tela (800 mg PO BID) or Pbo, until disease progression/unacceptable toxicity, and were stratified by prior PD-(L)1 inhibitor therapy (Y/N) and IMDC prognostic risk group. Primary endpoint was progression-free survival (PFS; RECIST 1.1) by blinded independent radiology review. The study was designed to detect a PFS hazard ratio (HR) of 0.69 w/ alpha 0.05 and 85% power. Data cutoff date: August 31, 2020. Results: 444 pts were randomized (221 Tela+Cabo; 223 Pbo+Cabo). Baseline characteristics were balanced between arms. Median follow-up was 11.7 mo; 276 pts received prior ICI, including 128 w/ prior nivo/ipi. Median PFS (mPFS) was 9.2 mo for Tela+Cabo vs 9.3 mo for Pbo+Cabo (HR = 0.94; 95% CI: 0.74, 1.21; stratified log-rank P= 0.65) with overall response rates (ORR; confirmed) of 31% with Tela+Cabo vs 28% Pbo+Cabo, respectively. Overall survival was not mature at data cutoff. In a prespecified subgroup analysis in pts w/ prior ICI, mPFS was numerically longer w/ Tela+Cabo than Pbo+Cabo (11.1 vs 9.2 mo, respectively; unstratified HR = 0.77; 95% CI: 0.56, 1.06). In the Pbo+Cabo arm, mPFS was 9.2 mo for pts w/ prior ICI exposure and 9.5 mo for pts without, and ORR was 32% and 20%, respectively; if ICI included nivo/ipi, ORR was 37%. Rates of adverse events (AEs) were similar between arms.Grade 3-4 AEs occurred in 71% of Tela+Cabo pts and 79% of Pbo+Cabo pts and included hypertension (17% vs 18%) and diarrhea (15% vs 13%). Cabo was discontinued due to AEs in 10% of Tela+Cabo pts and 15% of Pbo+Cabo pts. Conclusions: The addition of Tela did not improve the efficacy of Cabo in mRCC in this study. Tela+Cabo was well tolerated with AEs consistent with known risks of both agents. The study provides valuable insight on efficacy outcomes of a contemporary population of pts w/ mRCC who receive Cabo in the 2/3L setting. Clinical trial information: NCT03428217.

4563 Background: Previous reports have shown that the baseline neutrophil-to-lymphocyte ratio (NLR) is associated with prognosis in patients with mRCC. However, NLR has not been shown to reliably predict for response to IO. Retrospective analyses in metastatic melanoma and mRCC have shown an association of eosinophilia with improved outcomes to single agent immunotherapy. We sought to evaluate and compare the baseline NLR and NER with response to ipi/nivo in patients with mRCC. Methods: A retrospective review of patients with mRCC treated at the Vanderbilt-Ingram Cancer Center or Duke Cancer Institute with ipi/nivo was performed. Patients with clear cell histology and a baseline complete blood count with differential were included. Patients previously treated with IO were excluded. Patients were separated into groups (above and below the median) based on baseline median NER and baseline median NLR. Analyses of progression free survival (PFS) and overall survival (OS) were conducted using the log rank test. The odds ratio (OR) for objective response rate (ORR) was analyzed using Fisher’s exact test. Results: 111 patients met inclusion criteria. The median age was 60, 77% of patients were male, 68% had prior nephrectomy, 74% were naïve to systemic therapy, and 84% were IMDC intermediate/poor risk. The median NER was 25.0 and median NLR was 3.4. Patients with < median baseline NER had significant improvement in PFS, OS, and ORR (see table). Patients with < median baseline NLR had significant improvement in OS but not in PFS or ORR. Conclusions: Baseline NER was associated with improved outcomes with ipi/nivo. While both NER and NLR were associated with improved OS, only NER was additionally associated with both improved PFS and ORR. With multiple first-line treatment options for mRCC, baseline NER may serve as an early non-invasive predictor for response to ipi/nivo.[Table: see text]

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]

TPS4591 Background: ABACUS and PURE-01 trials demonstrated the activity of single agent atezolizumab and pembrolizumab respectively as neoadjuvant therapy for muscle invasive urothelial carcinoma (MIUC). However, downstaging to non-muscle invasive disease was noted in only 50 percent of patients. Resistance to programmed death (PD)- 1/L-1 antibodies is likely to include factors such as impaired dendritic cell maturation/function, infiltration of T-Regs and myeloid derived suppressor cells, impaired T-cell priming and T-cell trafficking in tumors. Cabozantinib is a tyrosine kinase inhibitor which targets MET, AXL, MER, Tyro3 and VEGFR2. Cabozantinib has a unique immunomodulatory profile and has demonstrated clinical activity as monotherapy and in combination with PD-1/L1 antibodies in various solid tumors including UC, renal cell cancer, castrate- resistant prostate cancer, and non-small cell lung cancer. We hypothesize that the combination of cabozantinib and atezolizumab as neoadjuvant therapy for MIUC would improve rates of pathologic downstaging compared to single-agent checkpoint inhibitors. Methods: ABATE(NCT04289779) is an open-label, single arm, multi-center study to assess the efficacy and safety of cabozantinib with atezolizumab as neoadjuvant therapy for cT2-T4aN0/xM0 MIUC. An estimated 38 patients will be enrolled and receive cabozantinib 40 mg PO daily with atezolizumab 1200mg every 3 weeks for a total duration of 9 weeks followed by radical cystectomy. Adults (≥18 years) with resectable UC who are either cisplatin-ineligible or decline cisplatin are eligible. Patients are required to have an ECOG PS of 0-2 and provide tumor tissue for PD-L1 analysis. UC should be predominant component (≥ 50%). Previous systemic anticancer therapies for MIUC are not permitted. CT/MRI will be performed before investigational therapy and cystectomy. Primary endpoint is pathologic response rate defined as the absence of residual muscle-invasive cancer in the surgical specimen ( < pT2). Secondary endpoints are safety and toxicity, pathologic complete response rate and event-free survival. Exploratory end points include patient-reported outcomes and outcome associations with biomarkers. Accrual began May 2020. Clinical trial information: NCT04289779.

431 Background: A mammalian target of rapamycin (mTOR) inhibitor, everolimus, showed activity in patients with metastatic urothelial carcinoma (mUC) including an exceptional objective response in a patient with a deleterious TSC1 mutation. Sapanisertib is a potent inhibitor of mTOR complex 1 and 2. Here, we present the data from a phase II study of sapanisertib in patients with TSC1- or TSC2-mutated mUC. Methods: Eligible mUC patients with a TSC1 or TSC2 mutation received sapanisertib 3mg po daily on days 1 through 28 every 28 days. Primary endpoint was the overall response rate. Tumor samples were submitted for central confirmation of the mutation. A prescreening test for TSC1/2 mutation was available at a central lab for those with unknown mutational status. Results: Tumor samples from 41 patients were submitted for either prescreening (n=24) or confirmation (n=17). Of 24 prescreening patients, 4 (16%) had TSC1 mutation; 2 (8%) had TSC2 mutations. Of 17 confirmatory testing, 16 were confirmed by the central lab. Of 23 potentially eligible patients with a TSC1 or TSC2 mutation, 17 (14 TSC1 and 3 TSC2) were enrolled. Baseline characteristics of these 17 patients are shown. Four patients with TSC1- mutated mUC were deemed non-evaluable for response; two withdrew consent before starting sapanisertib to pursue an alternative therapy, and the other two withdrew consent with an adverse event before completing the first cycle. Of 13 evaluable patients, no objective response was observed. Although 4 patients had stable disease (SD) at their first restaging scan, none were confirmed to have SD with a subsequent scan. Median overall survival is 3.4 months. Four patients withdrew consent due to adverse event. Most common adverse events were hyperglycemia (80%), Cr elevation (53%) and AST increased (46.7%). No treatment-related death was observed. Conclusions: Sapanisertib did not result in any objective response in 13 patients with TSC1- or TSC2-mutated mUC. Given the lack of clinical activity, and problems with tolerance of sapanisertib, the trial was terminated early for futility. Future studies of an mTOR inhibitor or other targeted agent in the mTOR pathway should examine molecular alterations beyond TSC1 or TSC2. Clinical trial information: NCT03047213 . [Table: see text]

341 Background: Neutrophilia is known to be associated with worse prognosis in metastatic renal cell carcinoma (mRCC); however, less is known about the role of eosinophils in the response to immunotherapy (IO). We investigated the association of the baseline neutrophil to eosinophil ratio (NER) with outcomes to IO-based combination treatment in mRCC. Methods: Patients with mRCC treated with ipilimumab plus nivolumab, pembrolizumab plus axitinib, or avelumab plus axitinib at the Vanderbilt-Ingram Cancer Center were retrospectively identified. Patients on >10mg prednisone and patients with prior IO were excluded. Baseline NER (at time of first IO) and association with progression free survival (PFS), overall survival (OS), and objective response rate (ORR) were investigated. Data cutoff was 9/1/2020. Analysis for PFS and OS was performed using the log-rank test and Mantel-Haenszel method, and analysis of the odds ratio for ORR was performed using Fischer’s exact test. Results: Sixty-one patients were identified: 89% clear cell histology, 74% prior nephrectomy, 69% IMDC intermediate risk, and 72% treatment-naïve. Patients with baseline NER < median (N=31) had improved clinical outcomes compared to patients with baseline NER > median (N=30) (Table). Improvement in PFS by NER was maintained when stratified by anti-PD-1/CTLA-4 and anti-PD(L)-1/VEGF (p= 0.0062 and p= 0.049); however, differences in OS and ORR were no longer significant. The median baseline NER among patients with partial response (PR) was significantly lower at 22.7 (95% CI 18.9-31.1) vs. 51.6 (95% CI 39.5-93.1) among those with progressive disease (PD) (p= 0.0054). For comparison, the median neutrophil to lymphocyte ratio was not significantly different between PR (2.60) and PD (3.84, p= 0.056). Conclusions: Patients with a low baseline NER treated with IO-based combinations had improved clinical outcomes compared to patients with a high baseline NER. Additional investigation of this parameter in larger cohorts is warranted. [Table: see text]

7 Background: We previously reported that cediranib, a vascular endothelial growth factor receptor tyrosine kinase inhibitor, combined with olaparib, a poly (ADP-ribose) polymerase inhibitor, prolonged radiographic progression-free survival (rPFS) compared with olaparib alone in patients with mCRPC. Herein, we present updated clinical data in the overall population and in subgroups by homologous recombination (HR) gene status. Methods: Men with a minimum of one prior line of systemic therapy for mCRPC were randomized 1:1 to receive olaparib 200 mg by mouth twice daily with cediranib 30 mg by mouth daily (C+O) or olaparib 300 mg by mouth twice daily (O). Patients were required to undergo a baseline metastasis biopsy. Next generation sequencing of HR genes was performed on available samples using BROCA-HR assay. HR deficiency (HRD) was defined by presence of homozygous deletions or deleterious mutations in HR genes including BRCA1, BRCA2, ATM, and others. The primary endpoint was rPFS and secondary endpoint was overall survival (OS). Results: Eighty-four patients were included in the analysis of whom 26 patients (31.0%) had HRD mCRPC. The most common HR gene alterations included BRCA2 (n=17, 20%), CDK12 (n=9, 11%), and ATM (n=7, 8%). Consistent with our prior report, in the overall cohort, C+O compared to O resulted in a significant improvement in rPFS (Table). The benefit in rPFS was most pronounced in patients with HRD mCRPC; however, there was no difference between arms in HR proficient (HRP) cancers. Independent of arm allocation, rPFS and OS were numerically longer in patients with HRD mCRPC compared to HRP mCRPC (rPFS: 8.8 versus 4.3 months, p=0.14; OS: 18.6 vs. 12.3 months, p=0.24). Conclusions: C+O improved rPFS in patients with mCPRC compared with O alone. The biomarker analyses revealed that the rPFS benefit of C+O over O is likely driven by patients with HRD mCRPC. Our data warrant validation and support further investigation of the combination of C+O in patients with HRD mCRPC. Clinical trial information: NCT02893917. [Table: see text]

443 Background: Enfortumab vedotin (EV) is an antibody-drug conjugate targeting Nectin-4, which is FDA approved for patients (pts) with treatment-refractory advanced urothelial cancer (aUC). The activity of EV in pt subsets of interest such as those with distinct histological variants has not been well defined. Methods: A retrospective study of pts with aUC treated with ≥1 dose of EV as standard of care (SOC) or on a clinical trial (if trial results already reported) at 12 US sites was undertaken. Objective response rate (ORR) was investigator-assessed for pts with at least one post-baseline scan or clear evidence of clinical progression. ORR was compared across subsets of interest using proportion test. Results: A total of 184 patients with aUC were included; median age at diagnosis 70, 20% women and 60% with definitive surgery. Most common primary sites included bladder (70%) and upper tract (28%). Majority of pts (72%) had pure urothelial histology (UH) per local review, but 26% had at least a component of variant histology (VH), most commonly squamous (14%), micropapillary (8%) or plasmacytoid (3%). EV was given as monotherapy in 84% and as SOC in 58%; and 81% had ≥ 1 prior treatment in the metastatic (met) setting. ECOG PS was ≥2 in 15%; 37% had baseline neuropathy, 15% diabetes and 9% had GFR≤30. At median follow-up of 37.0 (IQR: 20.5-60.2) months from initial diagnosis, median time from met diagnosis to EV start was 11.7 (IQR: 4.3 – 20.5) months. Median duration of EV was 5.5 (IQR: 1.4 – 6.7) months, and 84% of pts were evaluable for response. ORR for evaluable pts was 53% (8% CR, 45% PR); 25% had SD and 21% PD. Median PFS and OS were not yet reached. At data cutoff in 9/2020, 55% had stopped EV (36% due to PD, 19% intolerance) and 65% were alive. Comparison of ORR in subgroups of interest for 127 evaluable pts treated with EV monotherapy is shown in the table below. Notably, among 31 pts with FGFR3 alterations, 26 were evaluable and ORR was 46%. Conclusions: In a large, retrospective, multi-institutional cohort, responses to EV were observed across a broad range of aUC pts, including pts with variant histology component, FGFR3 alterations and also in populations previously excluded from clinical trials such as pts with GFR

5027 Background: SG is an antibody-drug conjugate consisting of a humanized monoclonal anti–Trop-2 antibody coupled to the cytotoxic agent, SN-38, via a unique hydrolyzable linker. The epithelial cell surface antigen, Trop-2, demonstrates greater expression between UC vs normal tissue, and is a promising target. In a phase 1/2 basket study (IMMU-132-01), SG showed an overall response rate (ORR) of 31% and manageable toxicity in 45 pts with mUC who had a median of 2 (range 1–6) prior therapy lines (Tagawa 2019 ASCO GU). Recent interim results for cohort 1 of the TROPHY-U-01 study in 35 pts with mUC who progressed on platinum and CPI therapy demonstrated an ORR of 29% in pts with a median of 3 prior treatment lines (range 2–6) (Tagawa 2019 ESMO). The most common grade ≥3 treatment-related AE (TRAE) was neutropenia. Methods: TROPHY-U-01 (NCT03547973) is a global, open-label, phase 2 trial evaluating the antitumor activity of SG (10 mg/kg, days 1 and 8 of 21-day cycles) in pts with advanced UC with measurable disease and ECOG PS 0 or 1. Cohort 2 includes platinum-ineligible pts who progressed after CPI therapy in the first-line metastatic setting. The primary objective is ORR evaluated with RECISTv1.1 by central review. Secondary objectives include progression-free survival, overall survival, and duration of response. Results: 18 pts with baseline tumor assessment (50% male; median age 79 y [range 57–87], 67% visceral metastases; 28% liver metastases) received a median of 2 (range 1–5) prior therapies. At a median follow-up of 6 months, ORR was 28% (5/18) with 4 confirmed PRs, and 1 PR pending confirmation. The majority of pts (61% [11/18]) had target lesion reduction. The safety profile was consistent with prior reports. Key grade ≥3 TRAEs were neutropenia (39%), fatigue (33%), diarrhea (28%), leukopenia (22%), anemia (17%), and febrile neutropenia (11%). No events of interstitial lung disease, ocular toxicities, or grade > 2 neuropathy were reported. There were no treatment-related deaths. Conclusions: In cisplatin-ineligible pts, the ORR for currently approved first-line CPI treatments is ~23–29% (Balar 2017 Lancet; Vuky 2018 ASCO). These preliminary data with SG show a manageable safety profile with an encouraging ORR of 28% and support the development of SG in platinum-ineligible pts with mUC who have progressed after CPI therapy. Clinical trial information: NCT03547973 .

111 Background: Cediranib, a vascular endothelial growth factor receptor tyrosine kinase inhibitor, suppresses expression of BRCA1, BRCA2, and RAD51 and increases sensitivity of tumors to poly (ADP-ribose) polymerase (PARP) inhibitors in vitro. Olaparib, a PARP inhibitor, demonstrates clinical efficacy in men with DNA repair deficient, mCRPC. We therefore performed a randomized phase 2 trial comparing olaparib with or without cediranib in men with mCRPC. Methods: Men with a minimum of one prior line of systemic therapy for mCRPC were randomized 1:1 to receive cediranib 30mg po daily plus olaparib 200mg po BID (Arm A) or olaparib 300mg BID alone (Arm B). At radiographic progression, patients (pts) in Arm B could crossover to Arm A. The primary endpoint was radiographic progression-free survival (rPFS). Secondary endpoints were objective response rate (ORR) and PSA50 decline rate (PSA50). Tumor biopsy specimens were obtained for biomarker analyses pre- and on-treatment. Results: Baseline characteristics of the 90 pts enrolled are summarized below. The median rPFS was 11.1 versus 4.0 months in Arm A and Arm B, respectively (Hazard Ratio 0.54, 95% CI 0.317, 0.928, p=0.026). Trends toward a higher ORR (19% and 12%), Disease Control Rate (Stable Disease + Partial Response) (77% and 64%,) and PSA50 (29% and 17%) were observed in Arm A compared to Arm B, respectively. Thirteen pts in Arm B crossed over to Arm A. One pt had a PR after crossover. Grade 3/4 adverse events (G3/4 AEs), irrespective of attribution, occurred in 77% and 58% of Arm A and Arm B pts, respectively. G3/4 AEs occurring in >10% of pts were hypertension (32%), fatigue (23%) and diarrhea (11%) in Arm A, and anemia (16%) and lymphopenia (11%) in Arm B. Conclusions: The cediranib/olaparib combination significantly improves rPFS in unselected, mCRPC pts. AEs were manageable. Analyses of mutation status in homologous recombination DNA repair genes are pending and will be key in interpreting the data. Clinical trial information: NCT02893917. [Table: see text]

TPS682 Background: Glutamine metabolism is upregulated in renal cell carcinoma (RCC) and important for RCC tumor cell proliferation and survival. CB-839 is a first-in-clinic, potent, oral inhibitor of the mitochondrial enzyme glutaminase (GLS), which controls a critical step in tumor cell metabolism of glutamine. CB-839 demonstrated synergistic anti-tumor activity when combined with cabozantinib, a VEGFR2/MET/AXL inhibitor, in preclinical RCC models. In a phase 1 study cohort, CB-839 plus cabozantinib as 2L+ therapy showed encouraging safety and efficacy results, with 50% overall response rate (ORR; RECIST v1.1) and 100% disease control rate in 10 patients with clear cell advanced/metastatic RCC (mRCC). A randomized, double-blind study comparing CB-839 plus cabozantinib vs. cabozantinib plus placebo has been initiated in patients with clear cell mRCC. Methods: In this ongoing international, randomized, double-blind, multi-center study, enrollment is planned for ~300 patients with clear cell mRCC. To be eligible, patients should have received 1-2 prior lines of systemic therapy for mRCC including ≥1 anti-angiogenic therapy or the combination of nivolumab + ipilimumab, have KPS ≥70%, measurable disease (RECIST v1.1), and no prior cabozantinib (or other MET inhibitor). Patients are randomized 1:1 to receive either CB-839 (800 mg twice daily per oral [PO] route) plus cabozantinib (60 mg daily PO) or cabozantinib plus placebo in 28-day cycles until disease progression or unacceptable toxicity. Patients are stratified by prior PD-1/PD-L1 inhibitor therapy and by IMDC prognostic risk group (favorable vs. intermediate vs. poor). The primary endpoint is progression-free survival (PFS) per RECIST v1.1, determined by blinded independent radiology review. Secondary endpoints are investigator-assessed PFS and overall survival. Safety, response per RECIST, and quality of life are also assessed. Findings of this randomized, international clinical trial will inform the efficacy and safety profile of CB-839, a first-in-clinic metabolic inhibitor, in combination with cabozantinib in patients with mRCC. Clinical trial information: NCT03428217.

Hypothermia is a common problem for surgical patients and can result in many complications. Because few studies compare methods of passive warming, we used an unblinded, prospective, experimental, randomized design to compare the effectiveness of two passive methods of normothermia management in the postanesthesia care unit (PACU). We assigned a total of 578 adult ambulatory surgery patients to either a control group that was given two folded, warmed cotton blankets or a treatment group that was given a warmed, unfolded cotton sheet and cotton blanket. We recorded patients' temperatures on their arrival in the PACU and at 30 minutes after arrival. The treatment group had temperatures that were significantly higher than those of the control group 30 minutes after arrival in the PACU, and the treatment group experienced a greater change in temperature from baseline measurements to those taken at 30 minutes. The treatment group also used fewer warmed blankets, resulting in cost savings for the PACU.

In this case report, we describe the first account in the literature of a patient who presented with extramedullary myeloid sarcomas (EMS) and Ph+ AML without leukemic manifestations. EMS are rare, destructive, extramedullary tumor masses that consist of immature leukemia cells. These tumors can occur anywhere in the body and have to be differentiated from lymphoma, carcinoma or infectious processes. We report a previously healthy 61-year-old male who presented with progressive left-sided hip pain. Magnetic resonance imaging (MRI) of the left hip joint revealed an extensive lytic lesion with pathological fracture of the femur. The lesion was confirmed by biopsy to be EMS with bcr-abl rearrangement in tumor cell nuclei by fluorescence in situ hybridization (FISH). Laboratory tests showed normal metabolic and complete blood counts with normal differential. Peripheral blood RT-PCR for bcr-abl was negative. Bone marrow examination revealed a normocellular with progressive trilineage hematopoiesis and no evidence of increased blast count. On the basis of available literature for the treatment of EMS, our patient received standard AML induction chemotherapy consisting of idarabucin and cytarabine. After cytogenetics studies of the bone marrow revealed bcr-abl rearrangement, we discontinued further chemotherapy and managed the patient with imatinib mesylate 400 mg p.o.q. day. Follow-up at time of manuscript preparation, the patient remains in complete cytogenetic remission (CCR) for 22 months. To the best of our knowledge, this is the first case report of Ph+ AML presenting as a primary EMS without leukemic manifestations.

Purpose Determine response rate, time to disease progression, and toxicity of the proteasome inhibitor PS-341 in patients with stage IV renal cell cancer. Patients and Methods PS-341 1.5 mg/m2 was administered intravenously twice weekly for 2 weeks every 21 days. Dose escalation to 1.7 mg/m2 ensued in the absence of grade 3 to 4 toxicities. Re-evaluation took place after three cycles. To assess proteasome inhibition, patients were randomly assigned to tumor core biopsy either before the first dose or after the third cycle of PS-341. Additionally, whole blood was collected at the same time intervals. Results Twenty-three patients were enrolled; 21 were assessable for response. Two patients were never treated (one patient refused treatment and one had insufficient tumor for biopsy). Eighteen patients completed at least three cycles of therapy; three patients experienced disease progression after two cycles. Grade 4 toxicities were arthralgia, diarrhea, and vomiting. Grade 3 toxicities included thrombocytopenia with one hemorrhage, anemia, febrile neutropenia, gastrointestinal toxicity, pain, fatigue, neuropathy (one sensory, one mixed sensorimotor), and electrolyte disturbances. Grade 1 to 2 neuropathy occurred in seven patients. One case of thrombosis and one case of pleural effusion occurred. Only one objective response was seen. Proteasome activity was measured by specific chymotryptic activity (SpA) and chymotryptic/tryptic activity (ChT:T). After PS-341, there was a decrease in mean whole blood SpA and ChT:T (P = .07 and .11, respectively). Conclusion Evidence is lacking for clinically significant activity of PS-341 in metastatic renal cell cancer. Insufficient biopsy and whole blood sample numbers preclude conclusions regarding proteasome inhibition within tumor. Further evaluation in this disease setting is not recommended.

In the testicular cancer post-treatment setting a rapidly growing retroperitoneal mass leads to a differential diagnosis including recurrent germ cell tumor, residual mature teratoma, or sarcomatoid degeneration. We report the case of a 27-year-old man with a large abdominal mass occurring in the setting of a mixed germ cell tumor after radical orchiectomy with primary chemotherapy followed by retroperitoneal lymph node dissection. Surgical excision of this mass followed by pathological review revealed an intra-abdominal desmoid tumor. Fluorescence in situ hybridization (FISH) for isochromosome 12p failed to demonstrate a germ cell tumor origin. This is the fourth such case of an intra-abdominal desmoid tumor after retroperitoneal lymph node dissection for testicular cancer in the urologic literature. This case highlights the need for careful consideration of a desmoid tumor when a rapidly growing spindle cell tumor is encountered in a post-treatment testis cancer patient.

Background Advanced renal cell cancer (RCC) continues to have a poor overall prognosis despite new FDA-approved therapies. Although taxane-based therapies are generally ineffective in RCC, research into the role of the von Hippel–Lindau protein has shown an association with microtubule dynamics. Mitotic kinesins are a class of molecular motors that also interact with microtubules and are required for proper mitotic function. SB-715992 is a new agent that inhibits the function of a mitotic kinesin known as kinesin spindle protein and leads to cell death. Patients and Methods Twenty patients with previously treated advanced RCC were enrolled on this phase II trial of SB-715992, with response rate as a primary endpoint. Results No patients responded with complete or partial remission. Six patients had stable disease, and 1 patient continues on therapy after 12 cycles. Common toxicities included anemia (80%), elevated creatinine (70%), lymphopenia (45%), fatigue (50%), hyperglycemia (50%), and dyspnea (45%). Reported grade 3/4 toxicities included dyspnea, fatigue, neutropenia with skin infection, dizziness, hyperuricemia, and hypertension. Conclusion This dose and schedule of SB-715992 does not appear to have a significant cytotoxic effect for patients with previously treated advanced RCC.

Background Urinary incontinence (UI) following radical prostatectomy is a well-recognized risk of the surgery. In most patients post-operative UI improves over time. To date, there is limited objective, quantitative data on the natural history of the resolution of post-prostatectomy UI. The purpose of this study was to define the natural history of post radical prostatectomy incontinence using an objective quantitative tool, the 1-hour standard pad test. Methods 203 consecutive patients underwent radical prostatectomy by a single surgeon between 03/98 & 08/03. A standardized 1-hour pad test was administered at subsequent postoperative clinic visits. The gram weight of urine loss was recorded and subdivided into four groups defined according to the grams of urine loss: minimal (1, 50 g). Patients were evaluated: at 2 weeks (catheter removal), 6 weeks, 18 weeks, 30 weeks, 42 weeks and 54 weeks. The data set was analyzed for average urine loss as well as grams of urine loss at each time point, the percentage of patients and the distribution of patients in each category. Results Mean follow up was 118 weeks. The majority of patients experienced incontinence immediately after catheter removal at 2 weeks that gradually improved with time. While continued improvement was noted to 1 year, most patients who achieved continence did so by 18 weeks post-op. Conclusion While the majority of patients experience mild to severe UI immediately following catheter removal, there is a rapid decrease in leaked weight during the first 18 weeks following RRP. Patients continue to improve out to 1 year with greater than 90% having minimal leakage by International Continence Society criteria.

OBJECTIVE To determine the prostate-specific antigen (PSA) response and time to PSA or radiographic progression in men with prostate cancer refractory to bicalutamide and/or flutamide therapy. PATIENTS AND METHODS Men with histologically confirmed prostate cancer not amenable to curative surgery or radiation therapy were eligible for the study if they had radiographic or PSA progression on at least one antiandrogen (not nilutamide) despite continued androgen suppression and standard antiandrogen withdrawal periods. All men received nilutamide 150 mg/day orally for ≥ 8 weeks unless there was unacceptable toxicity or disease progression. All men were evaluated for response, safety and toxicity. Baseline PSA levels, chest X-ray, bone scan and abdominopelvic computed tomography studies were obtained; the re-evaluation included PSA levels every 4 weeks and repeated imaging every 8 weeks in those with baseline abnormalities. The chest X-ray was repeated if there were pulmonary symptoms. Nineteen men were consented and 16 were evaluable for response. RESULTS The median (range) Gleason score was 7 (6–9) and the median number of previous second-line therapies was 2 (1–4). Bicalutamide therapy had failed in all patients. At baseline, 13 (of 16 men) had radiographically evident disease, nine with diffuse osseous and four with radiographically measurable metastases. There was no grade 3/4 toxicity; the commonest grade 1/2 toxicities were constipation (three), sensory neuropathy (four), fatigue (six), and visual changes (two) involving transiently altered colour vision and sensitivity to light, respectively. Responses included three partial and 13 with progressive disease. CONCLUSIONS The study was discontinued after a planned interim analysis because nilutamide had no apparent activity. Although well tolerated, nilutamide offers benefit to few men with prostate cancer in whom bicalutamide has failed.

There is compelling evidence that early hormonal therapy prolongs life in many stages of prostate cancer. Large-scale trials to answer this question have not yet been conducted in surgically treated patients or in patients with PSA-only relapse. Thus, many physicians and patients use early hormone therapy in PSA-only relapse. Many unique new agents are being tested in this population and may offer benefits. Patients and physicians are encouraged to participate in such trials, with hormone therapy reserved for subsequent use. Following failure of primary hormone therapy, a standard algorithm of care exists: antiandrogen withdrawal, use of alternative or first-line anti-androgens. ketoconazole. and chemotherapy. At each interval, clinical trials should be offered since none of these maneuvers are proven to prolong life.

15573 Background: Ispinesib is a novel kinesin spindle protein inhibitor that has significant antitumor activity in multiple tumor models and has demonstrated preliminary clinical activity in early phase I and II trials. A phase II study of Ispenisib in patients with metastatic RCC who had received at least one prior therapy was thus conducted. Methods: The primary objective was to assess the RECIST based overall response rate (RR) with optimal Simon two-stage design utilizing 10% and 30% RR as the null and alternative hypotheses, respectively. Eighteen pts were to be accrued during the first stage; if 3 or more responses (PR or CR) were seen, an additional 17 pts would be accrued. Further study would be recommended if 7 or more of the 35 total pts had a response. Secondary objectives included toxicity, time to progression, and overall survival. Pts were treated with 7 mg/m2 over one hour on days 1, 8, and 15 every 28 days with radiologic disease re- evaluation every 8 weeks. Results: 19 pts were accrued in 6 months. Baseline characteristics included clear cell histology in 74%, papillary in 11%, and unclassified in 11%; 1 or =2 prior therapies in 37% and 63%; prior immunotherapy in 53%, and prior sunitinib, sorafenib or bevacizumab in 79%; ECOG performance status 0 in 58% and 1 in 42%. 4 patients are too early for radiologic assessment. None of the 15 patients evaluable responded to treatment (95% CI: 0 - 21.8%). Seven patients (47%) experienced stable disease after 8 weeks. One patient experienced grade 3 neutropenia. No other grade 3 or 4 toxicities were attributable to drug. Grade 1 and 2 toxicities included: fatigue (28%), anemia (28%), leukopenia (33%), elevated alkaline phosphatase (18%), anorexia (11%), hyponatremia (11%), dyspnea (11%), headache (11%), and hypoalbuminemia (11%). Conclusions: Treatment with weekly Ispenesib in metastatic RCC is well tolerated but does not lead to objective responses. Under the hypothesis that Ispenesib is a cytotoxic rather than cytostatic agent, further evaluation in patients with metastatic RCC at this dose and schedule is not indicated. Supported by: NCI #N01-CM-62201 No significant financial relationships to disclose.

4669 Background: Determine PSA response, time to PSA progression and, in a subset with measurable disease at baseline, the objective response rate and time to radiographic progression in men with p...

Complementary/alternative medicines are used by up to 64% of patients with cancer.1 Little is known regarding interactions between multi-agent complementary/alternative medicines and single agent pharmaceuticals. The former may either mask or potentiate beneficial or adverse effects of conventional pharmaceuticals. Studies to address this issue have rarely been performed, and many physicians remain unaware that patients use complementary/alternative medicines due to lack of direct questioning or reporting. Despite the potential for harmful drug-herb-vitamin interactions, patients believe complementary/alternative medicines are nontoxic and may not report adverse effects. PC-SPES (Botanic Lab, Brea, California), a combination herbal preparation that is effective against prostate cancer, may interact with conventional pharmaceuticals. We report the difficulties of maintaining a therapeutic level of warfarin anticoagulation in a patient taking PC-SPES. CASE REPORT