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Introduction To describe the efficacy of infigratinib, a potent, selective fibroblast growth factor receptor (FGFR) 1-3 tyrosine kinase inhibitor, across lines of therapy (LOT) in patients with metastatic urothelial cancer (mUC). Patients and Methods Eligible patients had mUC and prior platinum-based chemotherapy, unless contraindicated, and activating FGFR3 mutation/fusion. Patients received infigratinib 125 mg orally daily (3 weeks on/1 week off) in a single-arm, open-label study. Primary endpoint: investigator-assessed confirmed objective response rate (ORR). Disease control rate (DCR), progression-free survival (PFS), best overall response (BOR) that included unconfirmed responses, and overall survival (OS) were also assessed. Subgroup analysis of efficacy and safety outcomes by LOT was performed. Results Sixty-seven patients were enrolled; 13 (19.4%) received infigratinib as early-line therapy for mUC due to ineligibility to receive platinum-based chemotherapy. Overall, ORR was 25.4% (95% CI 15.5-37.5) and DCR was 64.2% (95% CI 51.5-75.5). ORR was 30.8% (95% CI 9.1-61.4) with early-line infigratinib and 24.1% (95% CI 13.5-37.6) for ≥2 LOT. DCR was 46.2% (95% CI 19.2-74.9) for early-line and 68.5% (95% CI 54.4-80.5) for ≥2 LOT. PFS and OS appeared similar in both groups. Thirteen of 59 patients with a bladder primary tumor received early-line treatment with an ORR of 30.5% (95% CI 9.1-61.4), and 46 received ≥2 LOT with an ORR of 20.3% (95% CI 9.4-33.9); BOR was 38.5% (95% CI: 13.9-68.4%) and 42.6% (95% CI: 29.2-56.8%) in the early-line and salvage settings, respectively. Eight patients with upper tract urothelial carcinoma received salvage therapy (ORR, 50.0%; DCR, 100.0%). No significant differences in toxicities between LOT were observed. Conclusion Infigratinib has notable activity in patients with mUC regardless of LOT. The findings support the evaluation of infigratinib across different settings in mUC.

The NCCN Guidelines for Older Adult Oncology address specific issues related to the management of cancer in older adults, including screening and comprehensive geriatric assessment (CGA), assessing the risks and benefits of treatment, preventing or decreasing complications from therapy, and managing patients deemed to be at high risk for treatment-related toxicity. CGA is a multidisciplinary, in-depth evaluation that assesses the objective health of the older adult while evaluating multiple domains, which may affect cancer prognosis and treatment choices. These NCCN Guidelines Insights focus on recent updates to the NCCN Guidelines providing specific practical framework for the use of CGA when evaluating older adults with cancer.

Summary Background PD-1 and PD-L1 inhibitors are active in metastatic urothelial carcinoma, but positive randomised data supporting their use as a first-line treatment are lacking. In this study we assessed outcomes with first-line pembrolizumab alone or combined with chemotherapy versus chemotherapy for patients with previously untreated advanced urothelial carcinoma. Methods KEYNOTE-361 is a randomised, open-label, phase 3 trial of patients aged at least 18 years, with untreated, locally advanced, unresectable, or metastatic urothelial carcinoma, with an Eastern Cooperative Oncology Group performance status of up to 2. Eligible patients were enrolled from 201 medical centres in 21 countries and randomly allocated (1:1:1) via an interactive voice-web response system to intravenous pembrolizumab 200 mg every 3 weeks for a maximum of 35 cycles plus intravenous chemotherapy (gemcitabine [1000 mg/m2] on days 1 and 8 and investigator's choice of cisplatin [70 mg/m2] or carboplatin [area under the curve 5] on day 1 of every 3-week cycle) for a maximum of six cycles, pembrolizumab alone, or chemotherapy alone, stratified by choice of platinum therapy and PD-L1 combined positive score (CPS). Neither patients nor investigators were masked to the treatment assignment or CPS. At protocol-specified final analysis, sequential hypothesis testing began with superiority of pembrolizumab plus chemotherapy versus chemotherapy alone in the total population (all patients randomly allocated to a treatment) for the dual primary endpoints of progression-free survival (p value boundary 0·0019), assessed by masked, independent central review, and overall survival (p value boundary 0·0142), followed by non-inferiority and superiority of overall survival for pembrolizumab versus chemotherapy in the patient population with CPS of at least 10 and in the total population (also a primary endpoint). Safety was assessed in the as-treated population (all patients who received at least one dose of study treatment). This study is completed and is no longer enrolling patients, and is registered at ClinicalTrials.gov , number NCT02853305 . Findings Between Oct 19, 2016 and June 29, 2018, 1010 patients were enrolled and allocated to receive pembrolizumab plus chemotherapy (n=351), pembrolizumab monotherapy (n=307), or chemotherapy alone (n=352). Median follow-up was 31·7 months (IQR 27·7–36·0). Pembrolizumab plus chemotherapy versus chemotherapy did not significantly improve progression-free survival, with a median progression-free survival of 8·3 months (95% CI 7·5–8·5) in the pembrolizumab plus chemotherapy group versus 7·1 months (6·4–7·9) in the chemotherapy group (hazard ratio [HR] 0·78, 95% CI 0·65–0·93; p=0·0033), or overall survival, with a median overall survival of 17·0 months (14·5–19·5) in the pembrolizumab plus chemotherapy group versus 14·3 months (12·3–16·7) in the chemotherapy group (0·86, 0·72–1·02; p=0·0407). No further formal statistical hypothesis testing was done. In analyses of overall survival with pembrolizumab versus chemotherapy (now exploratory based on hierarchical statistical testing), overall survival was similar between these treatment groups, both in the total population (15·6 months [95% CI 12·1–17·9] with pembrolizumab vs 14·3 months [12·3–16·7] with chemotherapy; HR 0·92, 95% CI 0·77–1·11) and the population with CPS of at least 10 (16·1 months [13·6–19·9] with pembrolizumab vs 15·2 months [11·6–23·3] with chemotherapy; 1·01, 0·77–1·32). The most common grade 3 or 4 adverse event attributed to study treatment was anaemia with pembrolizumab plus chemotherapy (104 [30%] of 349 patients) or chemotherapy alone (112 [33%] of 342 patients), and diarrhoea, fatigue, and hyponatraemia (each affecting four [1%] of 302 patients) with pembrolizumab alone. Six (1%) of 1010 patients died due to an adverse event attributed to study treatment; two patients in each treatment group. One each occurred due to cardiac arrest and device-related sepsis in the pembrolizumab plus chemotherapy group, one each due to cardiac failure and malignant neoplasm progression in the pembrolizumab group, and one each due to myocardial infarction and ischaemic colitis in the chemotherapy group. Interpretation The addition of pembrolizumab to first-line platinum-based chemotherapy did not significantly improve efficacy and should not be widely adopted for treatment of advanced urothelial carcinoma. Funding Merck Sharp and Dohme, a subsidiary of Merck, Kenilworth, NJ, USA.

Background: Advance care planning (ACP) is recommended for older patients undergoing surgery. ACP consists of creating advance directives (ADs), identifying surrogate decision makers (SDMs), and documenting goals of care. We identified factors associated with documentation of preoperative ACP to identify opportunities to optimize ACP for older surgical patients. Methods: This was a retrospective study of surgical patients ≥70 years old who underwent elective, high-risk abdominal procedures between 01/2015-08/2019. Clinical data were obtained from our institution’s National Surgical Quality Improvement Project database. ACP metrics were extracted from the electronic medical record. We analyzed the data to identify patient factors associated with ACP metrics. We also analyzed whether ACP was more frequent for patients who experienced postoperative complications or death. Results: 267/1,651 patients were included. 97 patients (36%) had an AD available on the day of surgery, 57 (21%) had an SDM identified, and 31 (12%) had a documented goals of care conversation. On multivariable analysis, older age and white race were associated with an increased likelihood of having an AD available on the day of surgery. Women were 1.7 times more likely to have an SDM (p = 0.02). No patient or surgeon factors were significantly associated with goals of care documentation. ACP was not performed more frequently in patients who experienced postoperative complications or death. Conclusion: In this series, ACP was not routinely documented for older patients undergoing major surgery. ACP was not more frequent in patients who experienced complications or death, demonstrating the importance of universal preoperative ACP in older patients.

Detecting genomic alterations (GAs) in advanced urothelial carcinoma (aUC) can expand treatment options by identifying candidates for targeted therapies. Erdafitinib is FDA-approved for patients with platinum-refractory aUC with activating mutation or fusion in FGFR2/3. We explored the prevalence and spectrum of FGFR2/3 GAs identified with plasma cfDNA NGS testing (Guardant360) in 997 patients with aUC. FGFR2/3 GAs were detected in 201 patients (20%) with characterized activating GAs in 141 (14%). Our results indicate the Guardant360-based FGFR2/3 GA detection rate is similar to those described from previous studies employing tumor tissue testing, suggesting that plasma-based cfDNA NGS may non-invasively identify candidates for anti-FGFR targeted therapies.

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.

Purpose: Radium-223 is approved for metastatic castration-resistant prostate cancer (mCRPC) based on improved overall survival, and delay in skeletal related events. However, it is not associated with PSA or radiographic response, which poses a challenge in real-time assessment of its efficacy. Surrogate markers of treatment outcomes may facilitate tailoring treatment duration with radium-223, by limiting the duration of therapy with radium-223 in these patients. Here, we sought to investigate the utility of bone metabolic markers (BMMs) as surrogate markers of response to radium-223 in mCRPC. Patients and Methods: A prospective phase II trial of radium-223 plus enzalutamide (RE) versus enzalutamide alone was designed to assess surrogacy of BMMs with respect to response to radium-223. Enzalutamide was used as a comparator in lieu of placebo due to the progressive disease. Co-primary endpoints were relative change in serum BMM N-telopeptide (NTP) levels from baseline to 6 months between the two arms and safety and feasibility of the combination. Results: Thirty-nine men were randomized to RE (n = 27) or enzalutamide (n = 12). Combination was safe and feasible. Primary endpoint was met. A statistically significant relative change to NTP ratios between arms (0.64, 95% confidence interval, 0.51–0.81; P = 0.00048) favored RE versus enzalutamide. Overall, BMMs decreased with the RE therapy compared with enzalutamide. Improved PSA response rate in RE versus enzalutamide (P = 0.024), correlated with decline in BMMs. Conclusions: BMMs declined significantly with combination therapy, and were associated with improved outcomes. Upon external validation, BMMs may emerge as surrogate markers to monitor treatment with radium-223 in real-time.

Background: Relatives of patients with bladder cancer have been shown to be at increased risk for kidney, lung, thyroid, and cervical cancer after correcting for smoking-related behaviors that may concentrate in some families. We demonstrate a novel approach to simultaneously assess risks for multiple cancers to identify distinct multicancer configurations (multiple different cancer types that cluster in relatives) surrounding patients with familial bladder cancer. Methods: This study takes advantage of a unique population-level data resource, the Utah Population Database (UPDB), containing vast genealogy and statewide cancer data. Familial risk is measured using standardized incidence risk (SIR) ratios that account for sex, age, birth cohort, and person-years of the pedigree members. Results: We identify 1,023 families with a significantly higher bladder cancer rate than population controls (familial bladder cancer). Familial SIRs are then calculated across 25 cancer types, and a weighted Gower distance with K-medoids clustering is used to identify familial multicancer configurations (FMC). We found five FMCs, each exhibiting a different pattern of cancer aggregation. Of the 25 cancer types studied, kidney and prostate cancers were most commonly enriched in the familial bladder cancer clusters. Laryngeal, lung, stomach, acute lymphocytic leukemia, Hodgkin disease, soft-tissue carcinoma, esophageal, breast, lung, uterine, thyroid, and melanoma cancers were the other cancer types with increased incidence in familial bladder cancer families. Conclusions: This study identified five familial bladder cancer FMCs showing unique risk patterns for cancers of other organs, suggesting phenotypic heterogeneity familial bladder cancer. Impact: FMC configurations could permit better definitions of cancer phenotypes (subtypes or multicancer) for gene discovery and environmental risk factor studies.

Objective To review the genomic landscape of advanced urothelial carcinoma (UC) to assess the frequencies of EGFR and ERBB2 (HER2) alterations. Materials and methods Tumour specimens from 3753 patients with advanced UC were assayed with hybrid capture-based comprehensive genomic profiling of 180-395 genes. Tumour mutational burden (TMB) was assessed on 0.8 or 1.1 Mb of DNA, and is reported as mutations per megabase. Results In 3753 cases of UC, EGFR alterations were detected in 4.1% (154) and were most commonly amplifications (64%; 99/154), while exon 20 insertions (EGFRexon20ins ) were the second most common alteration (18%; 27/154). Alterations in ERBB2 were observed in 15% (552/3753) of cases and, similarly, ERBB2 amplification was the most commonly observed alteration (278/552; 50%); ERBB2exon20ins occurred in 3.6% (20/552) of cases. EGFRexon20ins and ERBB2exon20ins occurred in younger patients (median age 62 vs 69 years, P = 2.6E-2 and 60 vs 68 years, P = 7.8E-4), and these cases had significantly lower TMB (median 3.6 vs 7.2, P = 2.7E-4 and 2.5 vs 10, P = 1.2E-7) and less frequent TP53 alterations (3.7% vs 83%, P = 4.3E-14 and 20% vs 68%, P = 9.8E-4) compared to cases with other EGFR or ERBB2 alterations. Conclusion EGFR and ERBB2 alterations occur in 4% and 15% of UC, respectively. EGFRexon20ins and ERBB2exon20ins were present in 0.7% and 0.5% of UC overall and collectively define a small, but distinct, subset of UC with infrequent co-occurrence of other drivers and low TMB. Given recent promising clinical studies of inhibitors with activity against exon 20 insertions in non-small cell lung cancer, consideration should be given to developing a trial inclusive of patients with UC harbouring these alterations.

Background The veteran population has an increasingly high number of patients who have either survived, are currently living with, or are being treated for prostate cancer. Survivorship concerns related to the treatment of this disease is a relevant topic in the Veterans Health Administration, given the longevity of life with localized disease treatment and the fairly durable therapies for metastatic disease. Long-term androgen deprivation therapy (ADT) forms the backbone of treatment for advanced and metastatic castration-sensitive prostate cancer. Observations The potential bone-health complications resulting from treatment with ADT should be recognized as many patients live for prolonged periods with stable or controlled disease. It is well established that prolonged ADT can lead to significant bone loss and increased fracture risk, which increases all-cause mortality and disability. Bone-remodeling agents, such as bisphosphonates and receptor-activated nuclear factor κ-B ligand inhibitors, are recommended to reduce the risk of fragility fractures in patients at high risk due to diminished bone density while on hormone deprivation therapy for hormone-naive prostate cancer. These agents are also indicated at a higher dose to prevent complications from bone metastases in castration-resistant prostate cancer with bone metastases. Conclusions This article reviews recent studies on bone health in men with prostate cancer and presents an evidence-based algorithm for bone-health monitoring during treatment and recommended interventions.

BackgroundATLAS evaluated the efficacy and safety of the PARP inhibitor rucaparib in patients with previously treated locally advanced/unresectable or metastatic urothelial carcinoma (UC).MethodsPatients with UC were enrolled independent of tumor homologous recombination deficiency (HRD) status and received rucaparib 600 mg BID. The primary endpoint was investigator-assessed objective response rate (RECIST v1.1) in the intent-to-treat and HRD-positive (loss of genome-wide heterozygosity ≥10%) populations. Key secondary endpoints were progression-free survival (PFS) and safety. Disease control rate (DCR) was defined post-hoc as the proportion of patients with a confirmed complete or partial response (PR), or stable disease lasting ≥16 weeks.ResultsOf 97 enrolled patients, 20 (20.6%) were HRD-positive, 30 (30.9%) HRD-negative, and 47 (48.5%) HRD-indeterminate. Among 95 evaluable patients, there were no confirmed responses. However, reductions in the sum of target lesions were observed, including 6 (6.3%) patients with unconfirmed PR. DCR was 11.6%; median PFS was 1.8 months (95% CI, 1.6–1.9). No relationship was observed between HRD status and efficacy endpoints. Median treatment duration was 1.8 months (range, 0.1–10.1). Most frequent any-grade treatment-emergent adverse events were asthenia/fatigue (57.7%), nausea (42.3%), and anemia (36.1%). Of 64 patients with data from tumor tissue samples, 10 (15.6%) had a deleterious alteration in a DNA damage repair pathway gene, including four with a deleteriousBRCA1orBRCA2alteration.ConclusionsRucaparib did not show significant activity in unselected patients with advanced UC regardless of HRD status. The safety profile was consistent with that observed in patients with ovarian or prostate cancer.Trial registrationThis trial was registered inClinicalTrials.gov(NCT03397394). Date of registration: 12 January 2018. This trial was registered in EudraCT (2017–004166-10).

Histone deacetylase (HDAC) inhibition has sporadic clinical efficacy in urothelial carcinoma; the genomic basis for clinical response is not known. In two separate phase I clinical trials testing pharmacokinetic aspects of HDAC inhibitors in advanced solid tumors, we identified one patient with advanced urothelial carcinoma who had a complete response to belinostat, and one patient with advanced urothelial carcinoma who had a partial response to panobinostat. The archived tumors of the responders were genomically characterized in comparison to others with urothelial carcinoma on the trials. Urothelial carcinoma cell lines treated with panobinostat and belinostat were studied to elucidate the mechanisms of benefit. Notably, the urothelial carcinoma tumors that responded to HDAC inhibition had ARID1A mutations. ARID1A mutations were also noted in the tumors of three patients who had stable disease as their best response to HDAC inhibition. Corroborating the basis of sensitivity, transcriptional profiling of platinum-resistant ARID1A-mutated HT1197 cells treated with panobinostat reveals negative enrichment for both cyto-proliferative (MYC and E2F targets) and DNA repair gene sets, and positive enrichment for TP53 and inflammatory gene sets. Our study identifies ARID1A loss as a basis for clinical response to pan HDAC inhibition and offers avenues for potential rational therapeutic combinations with HDAC inhibitors in advanced urothelial carcinoma.

Background The authors evaluated mocetinostat (a class I/IV histone deacetylase inhibitor) in patients with urothelial carcinoma harboring inactivating mutations or deletions in CREB binding protein [CREBBP] and/or E1A binding protein p300 [EP300] histone acetyltransferase genes in a single‐arm, open‐label phase 2 study. Methods Eligible patients with platinum‐treated, advanced/metastatic disease received oral mocetinostat (at a dose of 70 mg 3 times per week [TIW] escalating to 90 mg TIW) in 28‐day cycles in a 3‐stage study (ClinicalTrials.gov identifier NCT02236195). The primary endpoint was the objective response rate. Results Genomic testing was feasible in 155 of 175 patients (89%). Qualifying tumor mutations were CREBBP (15%), EP300 (8%), and both CREBBP and EP300 (1%). A total of 17 patients were enrolled into stage 1 (the intent‐to‐treat population); no patients were enrolled in subsequent stages. One partial response was observed (11% [1 of 9 patients; the population that was evaluable for efficacy comprised 9 of the 15 planned patients]); activity was deemed insufficient to progress to stage 2 (null hypothesis: objective response rate of ≤15%). All patients experienced ≥1 adverse event, most commonly nausea (13 of 17 patients; 77%) and fatigue (12 of 17 patients; 71%). The median duration of treatment was 46 days; treatment interruptions (14 of 17 patients; 82%) and dose reductions (5 of 17 patients; 29%) were common. Mocetinostat exposure was lower than anticipated (dose‐normalized maximum serum concentration [Cmax] after TIW dosing of 0.2 ng/mL/mg). Conclusions To the authors’ knowledge, the current study represents the first clinical trial using genomic‐based selection to identify patients with urothelial cancer who are likely to benefit from selective histone deacetylase inhibition. Mocetinostat was associated with significant toxicities that impacted drug exposure and may have contributed to modest clinical activity in these pretreated patients. The efficacy observed was considered insufficient to warrant further investigation of mocetinostat as a single agent in this setting., After the genomic‐based selection of patients with urothelial cancer with inactivating mutations/deletions in the histone acetyltransferase genes CREBBP and/or EP300, single‐agent mocetinostat appears to be associated with significant toxicities that limit drug exposure. This may have contributed to the limited activity noted in the current phase 2 study (response rate of 11%) among heavily pretreated patients with platinum‐refractory disease.

OBJECTIVES To evaluate outcomes of patients achieving a post-treatment pathological stage of

Background HEK-NIZ985 (NIZ985) is a recombinant heterodimer of IL-15/IL-15Rα that expands effector lymphocytes and antitumor activity in animal models and a human clinical trial. We report interim data from the first-in-human study of NIZ985. Methods CNIZ985X2102J is an open-label Phase I/Ib dose-escalation/expansion trial evaluating the safety of subcutaneous NIZ985 three-times-weekly (TIW; 2-weeks-on/2-weeks-off) or once-weekly (QW; 3-weeks-on/1-week-off) as a single agent (SA) or in combination (CM) dosing with 400 mg of the PD-1 inhibitor spartalizumab every 4 weeks, in adults with metastatic/unresectable solid tumors. SA dosing was 0.25–4 µg/kg TIW or 2–10 µg/kg QW; CM dosing was 1 µg/kg TIW or 2–4 µg/kg QW. The primary objective was to characterize the safety and tolerability of NIZ985 ± spartalizumab. Data are presented for dose escalation, and CM-TIW expansion. Results Overall, 83 patients entered dose escalation (n=47) or CM-TIW expansion (n=36), of whom 63.8% (30/47) and 69.4% (25/36), respectively, had received ≥3 prior lines of antineoplastic treatment. At data cut-off (March 2, 2020), 91.6% (76/83) had discontinued study treatment. Adverse events (AEs) are summarized below (table 1). There were no dose-limiting toxicities during the first 28-day cycle in any cohort. Systemic skin AEs (Cycle 2) occurred in three SA-TIW patients receiving 2 or 4 µg/kg (bullous pemphigoid, purpura, vasculitis), limiting TIW escalation and initiating QW dose exploration; these were not observed at 1 µg/kg TIW (± spartalizumab) or for QW doses up to 10 µg/kg. CM-TIW dose expansion was therefore at 1 µg/kg; the recommended QW expansion dose is currently undetermined. For SA NIZ985, best overall response (RECIST 1.1) was stable disease (SD; 8/27 patients [29.6%]). Objective responses for NIZ985 plus spartalizumab (3/56 partial response [PR; 5.3%], 15/56 SD [26.8%]) occurred in both immuno-oncology treatment (IO)-naive and IO-experienced patients, including 5/8 IO-experienced melanomas (cutaneous: 3 SD, 1 PR; uveal: 1 SD). Systemic NIZ985 exposure was approximately dose-proportional after first dose for ≥1 µg/kg TIW and Conclusions NIZ985 is safe and tolerable at both TIW and QW dosing ± spartalizumab. It displays approximately dose-proportional, time-dependent PK, and a biomarker and lymphocyte response profile consistent with target engagement. Limited antitumor activity was reported during dose escalation; however, preliminary responses in both IO-experienced and IO-naive patients were seen in combination with spartalizumab that warrant further investigation. Ethics Approval The study was approved by an independent ethics committee and/or institutional review board at each participating site.

Background Infigratinib (BGJ398) is a potent, selective fibroblast growth factor receptor (FGFR) 1–3 inhibitor with significant activity in metastatic urothelial carcinoma (mUC) bearing FGFR3 alterations. It can cause hyperphosphatemia due to the “on-target” class effect of FGFR1 inhibition. Objective To investigate the relationship between hyperphosphatemia and treatment response in patients with mUC. Intervention Oral infigratinib 125 mg/d for 21 d every 28 d. Design, setting, and participants Data from patients treated with infigratinib in a phase I trial with platinum-refractory mUC and activating FGFR3 alterations were retrospectively analyzed for clinical efficacy in relation to serum hyperphosphatemia. The relationship between plasma infigratinib concentration and phosphorous levels was also assessed. Outcome measurements and statistical analysis Clinical outcomes were compared in groups with/without hyperphosphatemia. Results and limitations Of the 67 patients enrolled, 48 (71.6%) had hyperphosphatemia on one or more laboratory tests. Findings in patients with versus without hyperphosphatemia were the following: overall response rate 33.3% (95% confidence interval [CI] 20.4–48.4) versus 5.3% (95% CI 0.1–26.0); disease control rate 75.0% (95% CI 60.4–86.4) versus 36.8% (95% CI 16.3–61.6). This trend was maintained in a 1-mo landmark analysis. Pharmacokinetic/pharmacodynamic analysis showed that serum phosphorus levels and physiologic infigratinib concentrations were correlated positively. Key limitations include retrospective design, lack of comparator, and limited sample size. Conclusions This is the first published study to suggest that hyperphosphatemia caused by FGFR inhibitors, such as infigratinib, can be a surrogate biomarker for treatment response. These findings are consistent with other reported observations and will need to be validated further in a larger prospective trial. Patient summary Targeted therapy is a new paradigm in treating bladder cancer. In a study using infigratinib, a drug that targets mutations in a gene called fibroblast growth factor receptor 3 (FGFR3), we found that elevated levels of phosphorous were associated with greater clinical benefit. In the future, these data may help inform treatment strategies.

Background Infigratinib (BGJ398) is a potent and selective fibroblast grown factor receptor 1 to 3 (FGFR1-3) inhibitor with significant activity in patients with advanced or metastatic urothelial carcinoma bearing FGFR3 alterations. Given the distinct biologic characteristics of upper tract urothelial carcinoma (UTUC) and urothelial carcinoma of the bladder (UCB), the authors examined whether infigratinib had varying activity in these settings. Methods Eligible patients had metastatic urothelial carcinoma with activating FGFR3 mutations and/or fusions. Comprehensive genomic profiling was performed on formalin-fixed, paraffin-embedded tissues. Blood was collected for cell-free DNA analysis using a 600-gene panel. Patients received infigratinib at a dose of 125 mg orally daily (3 weeks on/1 week off) until disease progression or intolerable toxicity occurred. The overall response rate (ORR; partial response [PR] plus complete response [CR]) and disease control rate (DCR; CR plus PR plus stable disease [SD]) were characterized. Results A total of 67 patients were enrolled; the majority (70.1%) had received ≥2 prior antineoplastic therapies. In 8 patients with UTUC, 1 CR and 3 PRs were observed (ORR, 50%); the remaining patients achieved a best response of SD (DCR, 100%). In patients with UCB, 13 PRs were observed (ORR, 22%), and 22 patients had a best response of SD (DCR, 59.3%). Notable differences in genomic alterations between patients with UTUC and those with UCB included higher frequencies of FGFR3-TACC3 fusions (12.5% vs 6.8%) and FGFR3 R248C mutations (50% vs 11.9%), and a lower frequency of FGFR3 S249C mutations (37.5% vs 59.3%). Conclusions Differences in the cumulative genomic profile were observed between patients with UTUC and those with UCB in the current FGFR3-restricted experience, underscoring the distinct biology of these diseases. These results support a planned phase 3 adjuvant study predominantly performed in this population.

BGJ398, a potent and selective pan-FGFR antagonist, was prospectively evaluated in patients with metastatic urothelial carcinoma bearing a diverse array of FGFR3 alterations. Patients (N = 67) who were unable to receive platinum chemotherapy were enrolled. The majority (70.1%) had received two or more prior antineoplastic therapies. BGJ398 was administered orally at 125 mg/day on a 3 weeks on, 1 week off schedule until unacceptable toxicity or progression. The primary endpoint was the response rate. Among 67 patients treated, an overall response rate of 25.4% was observed and an additional 38.8% of patients had disease stabilization, translating to a disease control rate of 64.2%. The most common treatment-emergent toxicities were hyperphosphatemia, elevated creatinine, fatigue, constipation, and decreased appetite. Further examination of BGJ398 in this disease setting is warranted.Significance: BJG398 is active in patients with alterations in FGFR3, resulting in both reductions in tumor volume and stabilization of disease. Our data highlight putative mechanisms of resistance to the agent, which may be useful in following disease status. Cancer Discov; 8(7); 812–21. ©2018 AACR.This article is highlighted in the In This Issue feature, p. 781

Urothelial bladder cancer is the most common cancer of the urinary system. Exposure to toxins and carcinogens from urine plays an essential role in the pathogenesis of this disease.

// Andrew W. Hahn 1 , David M. Gill 1 , Benjamin Maughan 2 , Archana Agarwal 3 , Lubina Arjyal 2 , Sumati Gupta 2 , Jessica Streeter 4 , Erin Bailey 4 , Sumanta K. Pal 5 , Neeraj Agarwal 2 1 Department of Internal Medicine, University of Utah, Salt Lake City, UT, USA 2 Division of Medical Oncology, Huntsman Cancer Institute, Salt Lake City, UT, USA 3 Department of Pathology, University of Utah, Salt Lake City, UT, USA 4 Department of Pharmacy, Huntsman Cancer Institute, Salt Lake City, UT, USA 5 Department of Oncology, City of Hope Comprehensive Cancer Center, Duarte, CA, USA Correspondence to: Neeraj Agarwal, email: neeraj.agarwal@hci.utah.edu Keywords: circulating tumor DNA NGS, tumor tissue NGS, correlation, metastatic renal cell carcinoma Received: January 25, 2017 Accepted: March 25, 2017 Published: April 04, 2017 ABSTRACT Introduction: Tumor tissue and circulating tumor DNA (ctDNA) next-generation sequencing (NGS) testing are frequently performed to detect genomic alterations (GAs) to help guide treatment in metastatic renal cell carcinoma (mRCC), especially after progression on standard systemic therapy. Our objective was to assess if GAs detected by ctDNA NGS are different from those detected by tumor tissue NGS, specifically in patients with mRCC, and if these platforms are interchangeable or complimentary. Results: When controlling for genes tested by both platforms, the median mutation rate for ctDNA was similar to tissue (median 3.0 vs. 1.0, p = 0.14). However, the concordance rate between the two platforms was only 8.6%. When comparing GAs by molecular pathway, GAs in tumor tissue were more common for the DNA repair and epigenetic pathways. Materials and Methods: Results of NGS testing from tumor tissue and ctDNA from 19 sequential mRCC patients were compared. GAs in each were statistically evaluated using the Wilcoxon signed-rank test. The Fischer’s exact test was used to compare the incidence of mutations in selected molecular pathways. Conclusions: When controlling for genes tested by both platforms, similar number of GAs were detected by both tissue and ctDNA based NGS. However, there was discordance in the type of GAs detected suggesting that ctDNA NGS may be more reflective of dynamic tumor genomic heterogeneity. Hence, these two platforms may be considered complementary to each other, rather than interchangeable, for assessment of tumor GAs to guide selection of targeted clinical trial therapies.

Interpretation of next-generation sequencing (NGS) of tumor tissue in patients with advanced Urinary Tract Cancer (UTC) is performed to guide treatment selection but may reveal pathogenic variants with germline implications. We identified three patients with UTC with unexpected germline DNA repair gene mutations. Specific testing for these was prompted by the detection of these mutations by tumor NGS. All three patients were nonsmokers with a strong family history of cancer. Two patients had upper tract UTC with age at diagnosis in the 40 s. One had a family history suggestive of hereditary breast/ovarian predisposition and a FANCA mutation detected on NGS was confirmed to be germline. The second patient had a family history suggestive of Lynch syndrome but was found to have a germline BRCA2 mutation that was suggested by NGS. The third patient had bladder cancer at an advanced age, a family history of late-onset gastrointestinal malignancies that did not meet criteria for clinical testing for a hereditary cancer predisposition syndrome. NGS identified an MUTYH mutation, and targeted testing confirmed a monoallelic germline MUTYH mutation. Detection of variants with germline implications by tumor NGS may be clinically relevant for patients and their families and warrant genetic counseling and germline genetic testing. The prevalence of germline DNA repair defects in the context of inherited predisposition to UTC merits further study.

Relatives of bladder cancer (BCa) patients have been shown to be at increased risk for kidney, lung, thyroid, and cervical cancer after correcting for smoking related behaviors that may concentrate in some families. We demonstrate a new method to simultaneously assess risks for multiple cancers to identify distinct multi-cancer configurations (multiple different cancer types that cluster in relatives) surrounding BCa patients. We identified 6,416 individuals with urothelial carcinoma and familial information using the Utah Cancer Registry and Utah Population Database (UPDB). First-degree relatives, second-degree relatives, and first cousins were used to construct a familial enrichment matrix for cancer-types previously shown to be individually associated with BCa. K-medioids clustering were used to identify Familial Multi-Cancer Configurations (FMC). A case-control design and Cox regression with a 1:5 ratio of BCa cases to cancer-free controls was used to quantify the risk in specific relative-types and spouses in each FMC. Clustering analysis revealed 12 distinct FMCs, each exhibiting a different pattern of cancer co-aggregation. Of the 12 FMCs, four exhibited strong familial risk of bladder cancer along with specific patterns of increased risk of cancers in other sites (BCa FMCs), and were the focus of further investigation. Cancers at increased risk in these four BCa FMCs most commonly included melanoma, prostate and breast cancer and less commonly included leukemia, lung, pancreas and kidney cancer. A network-based approach can be used with familial data to discover new phenotype clusters for BCa, providing new directions for discovering patterns of cancer clustering.

Cell-free circulating DNA (cfDNA) can be used for noninvasive profiling of tumor genomic aberrations. We hypothesized that molecular alterations may inform prognostication in advanced urothelial carcinoma (aUC). We evaluated 124 aUC patients who underwent cfDNA analysis using a 73-gene sequencing panel (Guardant360). The association of molecular alterations and clinical factors with overall survival (OS) and failure-free-survival (FFS) was evaluated using the Kaplan-Meier method and Cox proportional-hazards regression. The median age was 72yr, and 65 patients (52.4%) received prior therapy with platinum, 21 (17.1%) with a taxane, and ten (8.1%) with a PD-1/PD-L1 inhibitor. At least one genomic alteration was detected in 112 patients (90.3%). The median number of alterations per sample was four (range 0-80). Commonly altered genes included TP53 (54.8%), PIK3CA (24.2%), ARID1A (22.6%), ERBB2 (19.4%), EGFR (16.1%), NF1 (13.7%), RB1 (12.9%), FGFR3 (11.3%), BRAF (10.5%), BRCA1 (10.5%), and RAF1 (8.9%). BRCA1 and RAF1 alterations were associated with worse OS (hazard ratio [HR] 2.48; p=0.07; HR 4.87; p=0.007) and FFS (HR 2.35; p=0.016; HR 2.40; p=0.047). Poor Eastern Cooperative Oncology Group performance status and the presence of visceral metastasis were associated with shorter OS; genomic evolution was observed. In conclusion, cfDNA molecular alterations were detected in most aUC patients. BRCA1 and RAF1 alterations were negatively prognostic, supporting further evaluation of DNA damage response and RAF kinase inhibitors. PATIENT SUMMARY: Noninvasive testing of cell-free circulating DNA in advanced urothelial carcinoma identifies clinically relevant molecular aberrations. Alterations in BRCA1 and RAF1 genes appear to be negatively associated with clinical outcomes, supporting further study of DNA damage response and RAF kinase inhibitors in selected patients.

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]

334 Background: Immune therapy combinations are now standard first-line therapy for pts with mccRCC. Cabo modulates key components of the immune system such as decreasing regulatory T-cells and increasing T-effector cell populations and is approved for treatment of mRCC. We hypothesize that Ave + Cabo will be safe and show clinical activity in mccRCC. Methods: Prospective phase I clinical trial using a 3+3 design with three planned dose cohorts: Cabo 20mg/day, 40mg/day and 60mg/day + Ave (10mg/kg q2weeks) in each arm. The primary endpoint was safety and identification of the recommended phase II dose (RP2D). Key secondary endpoints included objective response rate (ORR) and radiographic progression free survival (PFS). No dose modifications were allowed for Ave but dose delays were permitted. Dose reductions were allowed for Cabo. There were an additional 3 patients included in the final dose cohort as a confirmation of the RP2D. RECIST 1.1 was used to determine ORR. Treatment beyond progression was allowed. Results: Twelve patients with newly diagnosed mccRCC were enrolled from 08/2018 through 03/2020. Three patients were enrolled into the 20 and 40mg cohorts each, six patients enrolled in the 60mg cohort. IMDC risk: favorable 4 patients, intermediate 6 patients, poor 2 patients. No dose limiting toxicities were observed in any cohort. Only one SAE related to study treatment was observed, thromboembolism, after the DLT period. Immune related adverse events (irAE) occurred in six patients (50%) and included hypothyroidism, colitis, nephritis, allergic rhinitis and rash. Six patients required dose reductions of cabozantinib after the DLT period: one in the 40mg cohort and five in 60mg cohort, most frequently due to oral mucositis and hand foot syndrome. One patient discontinued Ave due to irAE (nephritis). No patients discontinued Cabo due to toxicity. The ORR was 33% (all PR). The clinical benefit rate (CR+PR+SD) was ~ 92%. One patient experienced PD on the first scan and then continued on the protocol treatment without further progression at the time of this report (follow up to date ~ 7 months). Seven of 12 pts are still on protocol treatment. Conclusions: Ave + Cabo in mccRCC is safe and preliminarily efficacious. Even though the DLT was not met in any of the cohorts, based on dose reduction required in 5 of 6 pts in the Cabo 60 mg cohort after the DLT period, the recommended RP2D dose for the combination is Cabo 40mg/day and Ave 10mg/kg q2 weeks. Safety and efficacy data will be elaborated in the meeting. * NA & BLM: equal contribution Clinical trial information: NCT03200587 .

Since the publication of the Society for Immunotherapy of Cancer’s (SITC) original cancer immunotherapy biomarkers resource document, there have been remarkable breakthroughs in cancer immunotherapy, in particular the development and approval of immune checkpoint inhibitors, engineered cellular therapies, and tumor vaccines to unleash antitumor immune activity. The most notable feature of these breakthroughs is the achievement of durable clinical responses in some patients, enabling long-term survival. These durable responses have been noted in tumor types that were not previously considered immunotherapy-sensitive, suggesting that all patients with cancer may have the potential to benefit from immunotherapy. However, a persistent challenge in the field is the fact that only a minority of patients respond to immunotherapy, especially those therapies that rely on endogenous immune activation such as checkpoint inhibitors and vaccination due to the complex and heterogeneous immune escape mechanisms which can develop in each patient. Therefore, the development of robust biomarkers for each immunotherapy strategy, enabling rational patient selection and the design of precise combination therapies, is key for the continued success and improvement of immunotherapy. In this document, we summarize and update established biomarkers, guidelines, and regulatory considerations for clinical immune biomarker development, discuss well-known and novel technologies for biomarker discovery and validation, and provide tools and resources that can be used by the biomarker research community to facilitate the continued development of immuno-oncology and aid in the goal of durable responses in all patients.

Background: Lysine-specific demethylase 1 (LSD1 or KDM1A) overexpression correlates with poor survival and castration resistance in prostate cancer. LSD1 is a coregulator of ligand-independent androgen receptor signaling promoting c-MYC expression. We examined the antitumor efficacy of LSD1 inhibition with HCI-2509 in advanced stages of prostate cancer. Methods: Cell survival, colony formation, histone methylation, c-MYC level, c-MYC expression, cell cycle changes and in vivo efficacy were studied in castration-resistant prostate cancer cells upon treatment with HCI-2509. In vitro combination studies, using HCI-2509 and docetaxel, were performed to assess the synergy. Cell survival, colony formation, histone methylation and c-myc levels were studied in docetaxel-resistant prostate cancer cells treated with HCI-2509. Results: HCI-2509 is cytotoxic and inhibits colony formation in castration-resistant prostate cancer cells. HCI-2509 treatment causes a dose-dependent increase in H3K9me2 (histone H3lysine 9) levels, a decrease in c-MYC protein, inhibition of c-MYC expression and accumulation in the G0/G1 phase of the cell cycle in these cells. PC3 xenografts in mice have a significant reduction in tumor burden upon treatment with HCI-2509 with no associated myelotoxicity or weight loss. More synergy is noted at sub-IC50 (half-maximal inhibitory concentration) doses of docetaxel and HCI-2509 in PC3 cells than in DU145 cells. HCI-2509 has growth-inhibitory efficacy and decreases the c-myc level in docetaxel-resistant prostate cancer cells. Conclusions: LSD1 inhibition with HCI-2509 decreases the c-MYC level in poorly differentiated prostate cancer cell lines and has a therapeutic potential in castration- and docetaxel-resistant prostate cancer.

Belinostat is a potent small molecule inhibitor that exerts its antitumor effect through inhibition of histone deacetylase. The purpose of this study was to evaluate the pharmacokinetics and pharmacodynamics of warfarin (as a reference drug metabolized by CYP2C9) in the presence and absence of belinostat. We conducted a phase I, single-center, open-label, drug–drug interaction study between belinostat and warfarin. In part I, patients were given warfarin 5 mg orally (day−14 and 3) and belinostat 1000 mg/m2 (days 1 through 5). Patients receiving benefit continued belinostat on days 1 through 5 every 21 days until disease progression, unacceptable toxicity, or per patient preference. A total of 18 patients were treated. With belinostat, the least-squared means for maximum concentration (C max), area under the curve0–∞, and area under the curve0–t of R-warfarin were slightly increased. However, for the more potent S-warfarin isomer, the same parameters were primarily contained within the pre-specified equivalence limits of 0.80 and 1.25, indicating there was no statistically significant interaction between S-warfarin and belinostat. The most common adverse events were nausea, vomiting, and fatigue. Three grade 3 adverse events (diarrhea 5.6 %, nausea 5.6 %, and vomiting 5.6 %) were thought to be treatment related. Progression-free survival ranged from 0.2 to 13.8 months in all patients. Belinostat did not significantly affect the pharmacokinetics and pharmacodynamics of warfarin, indicating no clinically relevant effect on the enzymatic activity of CYP2C9.

5038 Background: Infigratinib (BGJ398) is a potent and selective FGFR1–3 tyrosine kinase inhibitor (TKI), previously reported to be effective and well tolerated in patients with locally advanced/unresectable or metastatic urothelial carcinoma (mUC) bearing FGFR3 alterations [Pal et al. Cancer Discovery 2018]. However, this previous study did not examine differences in infigratinib activity based on number of prior lines of treatment (LOT). TKIs studied in other indications (e.g. VEGFRis in renal cell carcinoma) have shown consistent activity in both the first and later LOT. Given the effect seen with other TKIs, we sought to determine if infigratinib showed consistent treatment responses in patients with mUC according to LOT. Methods: Eligible patients had mUC and prior platinum-based chemotherapy unless contraindicated and activating FGFR3 mutations/fusions. Infigratinib was dosed at 125 mg orally daily (3 weeks on/1 week off). The primary endpoint of objective response rate (ORR: partial response [PR] and complete response [CR]) was assessed, as well as disease control rate (DCR: CR + PR + stable disease [SD]). After classification of LOT for each patient, subgroup analysis of response by LOT was performed. Results: 67 patients were enrolled; 81% received ≥1 prior LOT for mUC. 13 patients (19.4%) received infigratinib as 1st LOT for mUC due to ineligibility to receive platinum-based chemotherapy. ORR for the 67 patients was 25% (95% CI 15.5–37.5) and DCR was 64% (95% CI 51.5–75.5). The ORR with 1st-line infigratinib was 31% (95% CI 9.1–61.4) compared with 24% (95% CI 13.5–37.6) for 2nd and later (salvage) LOT. DCR was 46% (95% CI 19.2–74.9) for 1st-line and 69% (95% CI 54.4–80.5) for ≥2 LOT. 13 of the 59 patients with urothelial bladder carcinoma (UBC) received 1st-line treatment with an ORR of 31% (95% CI 9.1–61.4) and 46 patients in ≥2 LOT had an ORR of 20% (95% CI 9.4–33.9). All 8 patients with upper tract urothelial carcinoma (UTUC) received salvage therapy, with an ORR of 50% and a DCR of 100%. An analysis of other outcome measures (e.g. PFS, OS) will be presented. Conclusions: These results indicate that infigratinib has activity in patients with mUC regardless of LOT. Additionally, patients with UTUC showed a trend for better ORR and DCR. Taken together, these results support the ongoing adjuvant PROOF 302 study comparing infigratinib with placebo in patients with resected disease, assessing infigratinib in an even earlier setting in a UTUC-enriched population (NCT04197986). Clinical trial information: NCT01004224 .

5043 Background: Pathologic complete response (pCR) after NAC for MIBC is strongly correlated with long-term overall survival. However, there are sparse data on the risk of recurrence based on depth of pathologic response (pT0, pTa, pTis, pT1), and the differential impact of clinicopathologic factors and NAC regimen on recurrence. Methods: Baseline data on all pts with cT2-4N0-1 MIBC receiving NAC and who achieved < ypT2N0 disease at radical cystectomy (RC) from 9 international centers were obtained. The key outcome was time to recurrence (TTR) – defined as the time to any recurrence in the urinary tract or regional/distant metastasis, with death (in the absence of recurrence) considered a competing risk. Cox regression analysis was used to analyze the impact of clinical factors on recurrence. Results: A total of 506 pts were available. Median age was 66 years (range 33-86) and 78% (n = 396) were male; median follow-up after RC was 2.6 years. The majority of patients had pure urothelial histology (n = 371, 73%), and baseline stage was cT2N0 (n = 368, 73%), cT3-4N0 (n = 95, 19%) and TanyN1 (n = 43, 9%). NAC regimens were gemcitabine-cisplatin (GC, n = 296, 59%), dose-dense methotrexate-vinblastine-doxorubicin-cisplatin (ddMVAC, n = 141, 28%), split-dose GC (n = 29, 6%), MVAC (n = 29, 6%) and non-cisplatin based regimens (n = 11, 2%). At RC, 304 patients (60%) had ypT0N0 disease, 32 (6%) had ypTaN0, 107 (21%) had ypTisN0 and 63 (13%) had ypT1N0. Overall, 43 patients (8%) recurred with a median TTR of 56 weeks (range 7-251); 5-year freedom from recurrence was 87% (95% CI 83-91). The majority (n = 38) recurred outside the urinary tract. On multivariable analysis, ypTa (HR = 3.36 [1.24-9.11]) and ypT1 (HR = 2.88 [1.33-6.22], p = 0.013) disease at RC were predictors of shorter TTR, while female sex was associated with longer TTR (HR = 0.52 [0.27-0.98], p = 0.043). The type of NAC was not predictive of TTR (GC vs. other, HR = 1.49 [0.75-2.97], p = 0.26). Conclusions: To our knowledge, this is the largest study to quantify the risk of recurrence in pts achieving pathologic response after NAC and RC for MIBC. 8% of patients undergoing NAC and achieving < ypT2N0 at RC recurred. Residual ypTa and ypT1 disease conferred a significantly higher risk of recurrence, while ypTis did not; female sex was associated with a lower risk of recurrence. Importantly, the type of cisplatin-based NAC regimen used was not an independent predictor of recurrence.

439 Background: Cisplatin-based neoadjuvant chemotherapy (NAC) in MIBC improves survival which correlates with pathologic response (PaR) at radical cystectomy (RC). The combination of immunotherapy and NAC may improve PaR and outcomes in MIBC. We tested the efficacy and safety of nivolumab (N) with gemcitabine-cisplatin (GC) as neoadjuvant therapy for MIBC in our phase II trial (NCT03294304). Methods: Eligible pts with MIBC (cT2-T4a, N≤1, M0) who were candidates for RC were enrolled. Pts received C (70mg/m2) IV on D1, G (1000mg/m2) on D1,D8 and N (360 mg) IV on D8 every 21 days for 4 cycles followed by RC within 8 weeks. The primary endpoint was PaR (≤pT1,N0). Secondary objectives were safety of GC+N and PFS at 2 years. The correlative objectives based on pre-treatment biopsies were correlation of PaR with 1) WGS 2) molecular subtypes of BC; 3) PD-L1 expression; 4) baseline TILs, CD3, CD8 and CD56.. Evaluable pts. should have received at least 1 dose of N. PaR will be summarized by the PaR rate as estimated by the sample proportion with exact 95% confidence intervals. We specified a null PaR of 0.35 and an alternative hypothesis of 0.55; we will reject the null hypothesis if at least 20 of 41 pts. have a PaR. Results: Between Feb 2018 and June 2019, 41 pts. were enrolled (cT2N0 90%, cT3N0 7%, cT4N1 3%); 2 patients refused surgery but were included in ITT population. PaR was observed in 27/41 pts. (65.8%), including pts with N1 disease. The combination was safe with manageable toxicities and no deaths from treatment. Majority of AEs were from GC; the overall rates of grade 3-4 AEs was 20%, majority being neutropenia, thrombocytopenia and renal insufficiency. Immune related AEs were seen in 3 patients, 2 had "adenitis" which wasymptomatic,1 pt developed Guillian Barre Syndrome after surgery, which resolved with IVIG; and none of them required steroids. There was no delay in time to RC and no unexpected surgical complications from treatment. Patients are being followed for progression and survival. Correlative work is ongoing. Conclusions: Neoadjuvant N+GC is safe and effective in MIBC with significant pathologic downstaging rates and no added toxicities or delay to surgery. Clinical trial information: NCT03294304.

125 Background: RA, a bone targeting alpha radiopharmaceutical, and EZ, are approved for mCRPC. Per phase 3 SWOG0421 trial, men with mCRPC and a significant decline in serum bone metabolism markers (BMM) had improved survival with atrasentan, a bone targeting agent (PMID 24565955). We hypothesized that RA+EZ is safe, and decrease bone metabolism markers compared to EZ alone. Here we report the long-term follow up of the secondary clinical endpoints. Methods: In this phase 2 trial (NCT02199197), men with progressive mCRPC were treated with EZ (160 mg daily) ± RA (standard dose of 55 kBq/kg IV Q4 weeks x 6), until disease progression or unacceptable toxicities. Primary objectives: 1) changes in N-telopeptide compared from baseline to end of treatment; 2) safety. Secondary objectives: changes in 4 other markers of bone resorption or formation, and PSA progression free survival (PSA-PFS), radiographic PFS (rPFS) and overall survival (OS). Results: After a safety lead in phase (n=8), 39 men were randomized (2:1) to RA+EZ vs EZ. Median follow up is 19.3 months (range 3 – 24 months). Combining RA+EZ was safe (2018 ASCO annual meeting abstract: 5057) and met the primary endpoint (2018 ESMO annual meeting: Annals of Oncology). There was a consistent trend regarding PSA-PFS, rPFS and OS favoring RA+EZ over EZ. . . (Table). Notably, no bone fractures have occurred in either group with extended follow up. Conclusions: The use of RA+EZ was safe with a longer follow up with no increase in skeletal related events including fractures. All secondary endpoints, numerically favored RA+EZ vs EZ. Clinical trial information: NCT02614859.

440 Background: ATLAS (NCT03397394) evaluated the efficacy/safety of the PARP inhibitor (PARPi) rucaparib in patients (pts) with previously treated locally advanced/unresectable UC or mUC. Methods: Pts with measurable disease who had progressed after 1–2 prior regimens (ie, platinum-based chemotherapy [PBC] and/or immune checkpoint inhibitors [ICI]) were enrolled regardless of tumor homologous recombination deficiency (HRD) status. Prior PARPi was not allowed. Pts received rucaparib 600 mg PO BID. Baseline tumor tissue or archival tissue ≤6 mo without intervening therapy was required; serial circulating tumor DNA samples were collected. Primary endpoint was investigator-assessed objective response rate (RECIST v1.1) in the intent-to-treat and HRD-positive (defined as genomic loss of heterozygosity ≥10%) populations. Key secondary endpoints: progression-free survival (PFS) and safety. Clinical benefit rate (CBR) was defined as complete or partial response or stable disease (SD) lasting ≥16 weeks. Results: As of Oct 7, 2019, 97 pts were enrolled (median age 66 y [range, 39–87]); most were men (n=76, 78.4%) and had ECOG PS 1 (n=65, 67.0%). Sixty-six pts (68.0%) had both prior PBC and ICI. Twenty pts (20.6%) were HRD-positive, 30 (30.9%) were HRD-negative and 47 (48.5%) had unknown HRD status; 4 pts had a deleterious BRCA1/2 alteration. Median time on treatment was 54 d (range, 2–224). There were no confirmed responses. Of 96 evaluable pts, 27 (28.1%) had a best response of SD; CBR was 12.5% and median PFS was 1.8 mo. No relationship was observed between HRD status and clinical activity. Treatment was discontinued by 93 pts (95.9%), mainly due to radiologic or clinical progression (73.1%). Most frequent any grade treatment-emergent (any cause) adverse events were asthenia/fatigue (n=56, 57.7%), nausea (n=40, 41.2%), and anemia (n=34, 35.1%). Conclusions: Single agent rucaparib did not show activity in pts with previously treated advanced UC and enrollment was suspended at the first interim analysis. The safety profile was consistent with that observed in pts with ovarian cancer. Next generation sequencing–based characterization of the genomic landscape of mUC will be presented. Clinical trial information: NCT03397394.

576 Background: Infigratinib (BGJ398) is a potent and selective FGFR1–3 inhibitor with significant clinical activity in aUC bearing FGFR3 alterations. A common adverse event is hyperphosphatemia, a class effect associated with FGFR1 inhibition. We sought to better understand the relationship between hyperphosphatemia and response to infigratinib in patients with aUC. Methods: Eligible patients had aUC with activating FGFR3 mutations/fusions and had received prior platinum-based chemotherapy, unless contraindicated. Patients received infigratinib 125 mg orally daily (3w on/1w off) until disease progression or unacceptable toxicity. Calcium and phosphate levels within normal limits were required at enrollment. Efficacy was assessed by overall response rate (ORR) and disease control rate (DCR) based on RECIST 1.0 criteria. All patients received prophylaxis with the oral phosphate binder sevelamer. Hyperphosphatemia was defined as serum phosphorous >5.5 mg/dL, consistent with the threshold for action in the protocol. Results: Of the 67 patients enrolled, 48 (71.6%) had hyperphosphatemia on ≥1 post-baseline lab test. Efficacy findings in patients with vs without hyperphosphatemia were: ORR 33.3% (95% CI 20.4–48.4) vs 5.3% (95% CI 0.1–26.0), mPFS 4.9 months (95% CI 3.65–5.98) vs 1.84 months (95% CI 1.28–3.48), and mOS 8.74 months (95% CI 5.72–13.67) vs 7.62 months (95% CI 2.53–15.57). Median treatment length was 4.1 vs 1.4 months and mDOR was 5.0 vs 3.7 months for patients with vs without hyperphosphatemia, respectively. A landmark analysis at the 1-month mark was performed, and hyperphosphatemia (Y/N) was determined based on lab tests within the first month. The differences in efficacy outcomes were still observed. Conclusions: Hyperphosphatemia is a well-described class effect and pharmacodynamic biomarker of FGFR inhibitors, including infigratinib, and is generally reversible/easily managed with diet and phosphate binders. Our data support prior observations with FGFR inhibitors, suggesting that hyperphosphatemia is associated with treatment response and is not negatively associated with treatment length. Clinical trial information: NCT01004224.

TPS267 Background: RA is a calcium-mimetic radiopharmaceutical emitter of alpha particles that has been approved for treatment of mCRPC. Radiation plus checkpoint inhibitors has demonstrated promising efficacy in previous clinical trials (PMID 27466265, 23535954). Alteration to PD-1 expression has been observed with radium-223, suggesting potential synergy with Nivo (PMID 29137877). ctDNA concentration may accurately reflect overall tumor burden and response to immune therapy. ctDNA testing after 6 weeks of therapy predicts efficacy of immunotherapy in patients with metastatic NSCLC and urothelial carcinoma (PMID 30093454) and metastatic gastric cancer (PMID 30013197). Reduction of ctDNA correlated with both radiographic progression free survival (rPFS) and overall survival. We hypothesize that RA + Nivo will be safe and decrease ctDNA, which may predict response to therapy earlier than conventional scans. Methods: This is a single-arm phase I/II investigator initiated trial (NCT04109729). Primary objectives: 1) Safety, 2) Change in ctDNA after 6 weeks treatment compared to baseline. Secondary objectives: 1) PSA-PFS; 2) PSA 50% response rate; 3) Time to skeletal related event; 4) Bone metabolism marker response. Inclusion criteria: symptomatic bone metastasis, mCRPC, adequate hematopoiesis. Exclusion criteria: visceral metastasis, history of autoimmune disease and current use of immune suppression therapy. A total of 36 patients will be enrolled. Cycles are 28 days. ctDNA concentration will be measured using GuardantOMNI research platform which evaluates 500 genes. Treatment: RA (55 kBq/kg IV) monotherapy lead in for two cycles followed by RA plus Nivo (480mg IV) for an additional 4 cycles. Nivo monotherapy then continues for up to 2 years. ctDNA collected prior to combination therapy and 6 weeks after. Restaging scans done every 2 cycles while on radium-223 and every 3 cycles while on nivolumab. Clinical trial information: NCT04109729.

570 Background: AI is increasingly being used in clinical cancer genomics research. Probabilistic Graphical Models (PGMs) are AI algorithms that capture multivariate, mutli-level dependencies in complex patterns in large datasets while retaining human interpretability. We hypothesize that PGMs can identify clinical and genomic features that correlate with IO response in patients (pts) with mUC. Methods: In this retrospective study eligibility criteria were: diagnosis of mUC, receipt of IO for mUC, comprehensive genomic profiling data available from CLIA certified labs. The Bayesian Network (BN, PGM based AI) was used to discover clinical characteristics and selected genomic alterations relevant to IO response by RECIST 1.1 (investigator assessed). Results: Overall, 95 pts (73 men) with mUC were evaluated. 45 (47%) were ever smokers.The presented BN correctly captured the clinical landscape of mUC explaining significant relationship between included variables (p

Background Metastatic castration-resistant prostate cancer (mCRPC) is incurable, with most patients surviving less than 3 years. However, many treatments that extend survival have been approved in the past decade. Objective To describe the patient demographics, disease characteristics, treatment patterns, and outcomes in a cohort of Veterans diagnosed with mCRPC in the Veterans Health Administration. Design We identified 3,637 Veterans diagnosed with prostate cancer between January 2006 and August 2015 with evidence of mCRPC through December 2016. We described the most commonly used systemic mCRPC treatments according to mCRPC diagnosis era: Epoch 1 (2006–2010) or Epoch 2 (2011–2016). Patient demographics, disease characteristics, and treatment patterns were examined using descriptive statistics. An unadjusted Kaplan–Meier method was used to estimate the median time to biochemical progression and overall survival (OS) with 95% confidence intervals. Results The median age at initial prostate cancer diagnosis was 68 years. Approximately 67% of patients were non-Hispanic white, 29% were black, and 4% were other/unknown. A high-risk Gleason score (8–10) was reported in 748 (67%) of patients in Epoch 1 and 1578 (63%) of patients in Epoch 2, and the median prostate-specific antigen level at initial prostate cancer diagnosis was higher in Epoch 1 patients than in Epoch 2 patients (68 vs. 35 ng/ml). Following mCRPC diagnosis, the most common first-line therapies in Epoch 1 patients were docetaxel (83%) and abiraterone (9%), whereas Epoch 2 patients mainly received abiraterone (47%), docetaxel (36%), and enzalutamide (15%). In Epoch 1 and Epoch 2 patients, the median time to biochemical progression (unadjusted) was 9 and 13 months, respectively, and the median OS (unadjusted) was 15 and 23 months, respectively. Conclusions The introduction of new therapies has resulted in increased use of the noncytotoxic agents abiraterone and enzalutamide as first-line treatment in lieu of docetaxel. Our results suggest that more recently diagnosed patients (Epoch 2) have a delayed time to biochemical progression and longer OS (unadjusted) compared with patients diagnosed earlier (Epoch 1).

Purpose Tumor genomic profiling helps direct therapy for advanced urothelial carcinoma (UC). In the course of clinical care, we encountered a patient with a complete loss of SMARCB1 (switch/sucrose nonfermentable-related matrix-associated actin-dependent regulator of chromatin subfamily B member 1), which encodes INI-1 (integrase interactor 1), as the sole detected driver of their urinary tract tumor. Our objective was the identification and genomic characterization of urinary tract neoplasia with complete SMARCB1 loss. Patients and Methods Tissue from 1287 patients with UC was assayed by hybrid capture-based comprehensive genomic profiling (CGP) in the course of clinical care to evaluate genomic alterations (GA), such as, base substitutions, insertions/deletions, amplifications, copy number alterations, fusions/rearrangements, and targeted therapy opportunities. A total of 315 genes frequently altered in cancer were assayed. Results CGP identified 10 patients with SMARCB1 alterations. Of the 10 patients, 4 (1 each with renal pelvis, ureter, bladder, and unknown primary cancer) had complete loss of SMARCB1 , and 6 had loss of heterozygosity with an unknown effect on function or heterozygous loss. Patients with complete SMARCB1 loss had few or no additional alterations. Compared with conventional UC, the tumor mutational burden was significantly lower ( P = .004). All 4 patients with complete SMARCB1-loss tumors were Conclusion The genomic profiles of the tumors from patients with UC revealed a population of tumors driven by complete loss of SMARCB1 . This previously uncharacterized subset of INI-1–deficient urinary tract tumors might constitute a new tumor category that could be sensitive to targeted therapy, including EZH2 (enhancer of zeste homolog 2) inhibition. Clinical trial testing could be challenging owing to the rarity of the disease.

Background Family history of bladder cancer confers an increased risk for concordant and discordant cancers in relatives. However, previous studies investigating this relationship lack any correction for smoking status of family members. We conducted a population-based study of cancer risks in relatives of bladder cancer patients and matched controls with exclusion of variant subtypes to improve the understanding of familial cancer clustering. Methods Case subjects with urothelial carcinoma were identified using the Utah Cancer Registry and matched 1:5 to cancer-free controls from the Utah Population Database. Cox regression was used to determine the risk of cancer in first-degree relatives, second-degree relatives, first cousins, and spouses. A total of 229 251 relatives of case subjects and 1 197 552 relatives of matched control subjects were analyzed. To correct for smoking status, we performed a secondary analysis excluding families with elevated rates of smoking-related cancers. All statistical tests were two-sided. Results First- and second-degree relatives of case subjects had an increased risk for any cancer diagnosis (hazard ratio [HR] = 1.06, 95% confidence interval [CI] = 1.03 to 1.09, P < .001; HR = 1.04, 95% CI = 1.02 to 1.07, P = .001) and urothelial cancer (HR = 1.73, 95% CI = 1.50 to 1.99, P < .001; HR = 1.35, 95% CI = 1.21 to 1.51, P < .001). Site-specific analysis found increased risk for bladder (HR = 1.69, 95% CI = 1.47 to 1.95, P < .001), kidney (HR = 1.30, 95% CI = 1.08 to 1.57, P = .006), cervical (HR = 1.25, 95% CI = 1.06 to 1.49, P = .01), and lung cancer (HR = 1.34, 95% CI = 1.19 to 1.51, P < .001) in first-degree relatives. Second-degree relatives had increased risk for bladder (HR = 1.35, 95% CI = 1.2 to 1.5, P < .001) and thyroid cancer (HR = 1.18, 95% CI = 1.03 to 1.35, P = .02). Spouses showed an increased risk for laryngeal (HR = 2.68, 95% CI = 1.02 to 7.05, P = .04) and cervical cancer (HR = 1.57, 95% CI = 1.13 to 2.17, P = .007). These results did not substantively change after correction for suspected smoking behaviors. Conclusion Our results suggest familial urothelial cancer clustering independent of smoking, with increased risk in relatives for both concordant and discordant cancers, suggesting shared genetic or environmental roots. Identifying families with statistically significant risks for non-smoking-related urothelial cancer would be extremely informative for genetic linkage studies.

Lysine-Specific Demethylase 1 (LSD1) over-expression correlates with poorly differentiated neuroblastoma and predicts poor outcome despite multimodal therapy. We have studied the efficacy of reversible and specific LSD1 inhibition with HCI-2509 in neuroblastoma cell lines and particularly the effect of HCI-2509 on the transcriptomic profile in MYCN amplified NGP cells. Cell survival assays show that HCI-2509 is cytotoxic to poorly differentiated neuroblastoma cell lines in low micromole or lower doses. Transcriptional profiling of NGP cells treated with HCI-2509 shows a significant effect on p53, cell cycle, MYCN and hypoxia pathway gene sets. HCI-2509 results in increased histone methyl marks and p53 levels along with cell cycle arrest in the G2/M phase and inhibition of colony formation of NGP cells. Our findings indicate that LSD1 inhibition with HCI-2509 has a multi-target effect in neuroblastoma cell lines, mediated in part via p53. MYCN-amplified neuroblastoma cells have a targeted benefit as HCI-2509 downregulates the MYCN upregulated gene set.

O1 IL-15 primes an mTOR-regulated gene-expression program to prolong anti-tumor capacity of human natural killer cells #### Andreas Lundqvist1, Vincent van Hoef1, Xiaonan Zhang1, Erik Wennerberg2, Julie Lorent1, Kristina Witt1, Laia Masvidal Sanz1, Shuo Liang1, Shannon Murray3, Ola Larsson1

Background: For patients with metastatic urothelial carcinoma (mUC) that has progressed on or after platinum-based chemotherapy (cisplatin or carboplatin) and/or immune checkpoint inhibitors, there are currently no standard treatments, emphasizing the urgent unmet need for additional treatment options. Based on analysis of The Cancer Genome Atlas bladder cancer dataset, ≈60% of muscle invasive bladder tumors have homologous recombination (HR) deficiency (HRD), as defined by high genomic loss of heterozygosity (LOH) or a deleterious mutation in a DNA repair pathway gene. Poly(ADP-ribose) polymerase (PARP) inhibitors such as rucaparib exert their antitumor activity through synthetic lethality in cancer cells with HRD. Tumors with HRD have been shown to be sensitive to PARP inhibitors in breast, ovarian, and prostate cancers, and PARP inhibitors are approved for the treatment of patients with breast or ovarian cancer. Although there are little data on their activity in mUC, we hypothesize that PARP inhibition may have antitumor activity in this tumor type. The ATLAS (NCT03397394) trial is evaluating the efficacy and safety of the PARP inhibitor rucaparib as monotherapy for patients with locally advanced (unresectable) urothelial carcinoma or mUC previously treated with 1-2 anticancer treatments for advanced/metastatic disease. Methods: Eligible patients must have received 1-2 prior treatments (eg, platinum-based chemotherapy, immune checkpoint inhibitor, and/or clinical trial agent) and have radiographic progression, measurable disease (RECIST version 1.1), and adequate organ function. Tumor HRD is not required as rucaparib may potentially benefit patients with HR-proficient or HR-deficient tumors; however, fresh tumor or recently obtained archival tissue is mandatory for central HRD profiling. Prior PARP inhibitor treatment is an exclusion criterion. All patients will receive rucaparib monotherapy (600 mg BID) until disease progression or other reason for discontinuation. The primary endpoint is confirmed objective response rate (investigator assessed per RECIST version 1.1) in the intent-to-treat and HRD-positive (signature based on tumor genomic LOH) populations. Secondary endpoints include response duration, progression-free survival, overall survival, safety, and pharmacokinetics. Exploratory endpoints include evaluating plasma and tumor samples for biomarkers associated with response and resistance to rucaparib. The study has >90% power to reject the null hypothesis (P=0.10) at a one-sided 5% significance level if the true response rate for rucaparib is 20%. ATLAS is currently enrolling at ≈65 sites in 6 countries (France, Germany, Italy, Spain, United Kingdom, and United States), with a target enrollment of 200 patients. Citation Format: Petros Grivas, Min Yuen Teo, Nicholas Vogelzang, Ajjai Alva, Yousef Zakharia, Nabil Adra, Alexandra Drakaki, Arif Hussain, Rafael Morales-Barrera, Andrea Necchi, Alejo Rodriguez-Vida, Susan Feyerabend, Sumati Gupta, Debra H. Josephs, Yohann Loriot, Sandy Srinivas, Kenton Wride, Daleen Thomas, Rachel Dusek, Andrew D. Simmons, Dale Nepert, Simon Chowdhury. ATLAS: A Phase II, open-label study of rucaparib in patients with locally advanced or metastatic urothelial carcinoma [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr CT179.

4504 Background: Platinum-based chemotherapy for 1st-line treatment of pts with metastatic urothelial cancer (mUC) is typically administered for a fixed duration followed by observation until recurrence. PD-1 blockade with pembro improves survival of pts with mUC progressing despite platinum-based chemotherapy. We explored the potential benefit of earlier use of PD-1 blockade using a "switch maintenance" approach. Methods: Pts with mUC achieving at least stable disease after up to 8 cycles of 1st-line platinum-based chemotherapy were enrolled. Pts were randomized 1:1 to pembro 200 mg IV q3 weeks versus placebo for up to 24 months; pts progressing on placebo could cross over to pembro. Randomization was stratified based on pre-chemotherapy visceral metastases (Y/N) and response to 1st-line chemotherapy (CR/PR vs. SD). The primary objective was to determine the progression-free survival (PFS) as per irRECIST among pts treated with pembro versus placebo. Results: Between 12/2015 and 11/2018, 107 pts were randomized to placebo (n=52) versus pembro (n=55). The baseline pt characteristics are shown in the Table. Pts randomized to placebo and pembro received a median of 6 and 8 cycles, respectively. Excluding patients with baseline CRs, the objective response rate was 12% (5/42) on placebo and 22% (10/46) on pembro. Grade 3-4 treatment emergent adverse events occurred in 48% of pts on placebo and 56% on pembro. At a median follow-up of 14.7 months, 41 pts have died and 26/52 pts randomized to placebo have crossed over to pembro. PFS was significantly longer in patients randomized to pembro vs. placebo (Maximum Efficiency Robust Test p=0.036; log-rank p = 0.038). The 18-month restricted mean progression-free survival time was 5.6 months with placebo and 8.2 months with pembro (p=0.023). Conclusions: Switch maintenance pembro may “deepen” responses achieved with 1st-line chemotherapy. Switch maintenance pembro prolongs PFS in pts with mUC completing 1st-line platinum-based chemotherapy. Clinical trial information: NCT02500121. [Table: see text]

4510 Background: Infigratinib (BGJ398) is a potent and selective FGFR1–3 inhibitor with significant activity in patients (pts) with advanced or metastatic urothelial carcinoma (mUC) bearing FGFR3 alterations [Pal et al 2018]. Given the distinct biologic characteristics of upper tract UC (UTUC) and urothelial carcinoma of the bladder (UCB), we sought to determine if infigratinib had varying activity in these settings. Methods: Eligible pts had mUC with activating FGFR3 mutations/fusions and prior platinum-based chemotherapy, unless contraindicated. Pts received infigratinib 125 mg orally daily (3 wks on/1 wk off). Overall response rate (ORR: CR+PR) and disease control rate (DCR; CR+PR+SD) were characterized in UCB and UTUC pts. Comprehensive genomic profiling was performed on FFPE tissues in a CLIA-certified lab (Foundation Medicine; Cambridge, MA). Blood was collected for cell-free (cf)DNA analysis using a 600-gene panel on an Illumina HiSeq 2500 sequencer. Results: 67 pts were enrolled; the majority (70.1%) had received ≥2 prior antineoplastic therapies. ORR was 25.4% and DCR was 64.2%. In the 8 pts with UTUC, 1 CR and 3 PRs were observed (ORR 50%); the remainder had a best response of SD (DCR 100%). UTUC pts were predominantly 2nd line (62.5%), with only 2 (25%) showing response to previous treatment. In pts with UCB, 13 PRs were observed (ORR 22%), and 22 pts had a best response of SD (DCR 59.3%). Notable differences in genomic alterations between cohorts included a higher frequency of FGFR3-TACC3 fusions (12.5% vs 5.8%) and FGFR3 R248C mutations (50% vs 11.5%), and a lower frequency of FGFR3 S249C mutations (25% vs 59.6%) in UTUC vs UCB. Consistent with previous reports [Sfakianos et al 2016], UTUC pts had a differential frequency of alterations in HRAS, CDKN2B and ARID1A. Sufficient cfDNA yield was obtained in UTUC and UCB pts and a comprehensive comparison of these data will be presented. Conclusions: Differences in cumulative genomic profile were observed between UCB and UTUC in this FGFR3-restricted experience, underscoring the distinct biology of these diseases. Results with infigratinib in UTUC support a planned phase III adjuvant study predominantly in this population. Clinical trial information: NCT01004224.