Citations

Abstract Background Urinary tract infections (UTIs) are commonly treated in the emergency department (ED), and unfortunately, resistance to first-line agents is increasing. Objectives To characterize treatment of pyelonephritis in a nationally representative sample of ED patients and to identify patient- and treatment-specific factors associated with receiving initial inactive antibiotics. Methods We conducted a multicentre, observational cohort study utilizing the Emergency Medicine PHARMacotherapy Research NETwork (EMPHARM-NET), comprising 15 geographically diverse US EDs. All patients ≥18 years of age with a diagnosis of pyelonephritis between 2018 and 2020 were included. The primary endpoint was the proportion of patients who received initial inactive empirical antibiotic therapy and to identify predictive factors of inactive antibiotic therapy. Results Of the 3714 patients evaluated, 223 had culture-positive pyelonephritis. Median patient age was 50.1 years and patients were mostly female (78.3%). Overall, 40.4% of patients received an IV antibiotic, most commonly ceftriaxone (86.7%). The most frequently prescribed antibiotics were cefalexin (31.8%), ciprofloxacin (14.3%), cefdinir (13.5%) and trimethoprim/sulfamethoxazole (12.6%). Overall, 10.3% of patients received initial inactive therapy. After adjustment in a multivariable analysis, long-acting IV antibiotic was predictive of inactive therapy (OR 0.23, 95% CI 0.07–0.83). Conclusions In our prospective, multicentre observational study, we found that only 40.4% of patients with pyelonephritis received empirical IV antibiotics in the ED, contributing to inactive therapy. Receipt of long-acting IV antibiotics was independently associated with a decreased rate of initial inactive therapy. This reinforces guideline recommendations to administer long-acting IV antibiotics empirically in the ED upon suspicion of pyelonephritis.

601 Background: Neuroendocrine carcinomas (NEC) of the genitourinary (GU) tract, including small cell (SC) NEC and large cell (LC) NEC, are rare aggressive malignancies. Although highly sensitive to cisplatin-based chemotherapy, GU metastatic NEC (mNEC) have limited data to support next therapies. Lurbinectedin, a marine-derived alkylating drug and a selective inhibitor of oncogenic transcription and DNA repair pathways, is FDA-approved for small cell lung cancer (SCLC) after progression on frontline platinum-based therapy, with a disease control rate (DCR) of 68.6%. It is unknown whether DCR is similar in SCLC and GU mNEC. Methods: We report the first multi-institutional series (n=14) of lurbinectedin in GU mNEC. Imaging-based best overall responses (BOR) were noted as complete (CR), partial (PR), stable (SD), progressive (PD) or non-evaluable (NE). DCR includes CR, PR, and SD. We use the Kaplan-Meier method for overall survival (OS) and progression-free survival (PFS) from lurbinectedin start date. We define duration of response (DoR) from response date to progression or last contact date for patients (pts) with CR or PR. Results: Most pts had a median age at metastasis of 70.5 years (ICR: 64-74.5) [Table]. Primary locations were bladder (7/14, 50%), prostate (5/14, 35.7%) and ureter (2/14, 12.3%). Histology at diagnosis mostly consisted of mixed or pure SCNEC, with one exception of LCNEC. Most pts had visceral disease, prior immunotherapy and at least 2 prior lines of therapy for mNEC before lurbinectedin (8/14, 57.1%). DCR was 6/14 (42.8%), including 5 bladder pts and 1 prostate pt. Among bladder pts, BOR included one CR (1/7, 14.3%) for the LCNEC case, 2 PR (2/7, 28.6%), 2 SD (2/7, 28.6%) and 2 PD (2/7, 28.6%). Most prostate and ureteral pts either progressed on lurbinectedin or were NE (Prostate: 1 PR, 2 PD, and 2 NE; Ureteral: 1 PD and 1 NE). For all 14 pts, median OS was 11.47 months (95% CI: 2.17-13.63) and median PFS was 2.8 mo (1.4-10.9). Median DoR was 7.38 mo (2.3-9.53) for 4 responding pts (CR or PR). Treatment was stopped due to progression (9/14, 64.3%), three adverse events [thrombocytopenia, electrolyte abnormalities, cerebrovascular accident] (3/14, 21.4%), and pt preference (1/14, 7.1%). Conclusions: Lurbinectedin offers encouraging responses (DCR: 5/7, 71.4%) close to those in SCLC, in previously treated bladder mNEC. One CR was noted for a bladder pt with LCNEC. Responses were less appreciated in prostate and ureteral mNEC due to NE responses and limited number. Larger cohorts are needed to confirm survival benefit and genetic analyses are warranted to identify characteristics of responders. [Table: see text]

4597 Background: NCCRCC are a diverse group of rare diseases with limited data to guide treatment. CABO is highly effective in clear cell RCC, but it is unknown whether it is superior to SUN, the historic standard of care for metastatic NCCRCC. Methods: CABOSUN II (NCT03541902) was a randomized phase II study at 3 centers for patients (pts) with metastatic NCCRCC. Sixty pts were planned to detect CABO as better than SUN with a 1-sided test. Pts were randomized 1:1 to CABO 60mg daily or SUN 50mg daily (4 weeks on, 2 weeks off). SUN dose modification to 2 weeks on, 1 week off was allowed for toxicity. Stratification was by papillary RCC (PRCC) vs. non-PRCC (NPRCC), good/intermediate vs. poor risk disease by IMDC criteria, and prior TKI use. The primary outcome was progression-free survival (PFS) by RECIST v1.1 compared between the 2 arms using the log-rank test. Secondary outcomes were objective response rate (ORR), overall survival (OS), and adverse event (AE) rates (2-sided tests). Results: 32 pts were randomized to CABO (N=15) or SUN (N=17) between 9/2018 and 6/2021. The trial stopped early due to a change in standard therapy for PRCC not based on these pts’ outcomes. Age range was 22-88 years with medians 57 and 61 for CABO and SUN. Pts were primarily white (84%) and male (72%), with good/intermediate risk (88%), and these were balanced between arms. More pts on the CABO arm had bone metastases (62% vs. 24%). NPRCC were chromophobe (N=6; 5 randomized to SUN), unclassified (N=5), and MiT family translocation (N=3; all randomized to CABO). With median follow-up of 33.3 months and 20 PFS events, median PFS for CABO vs. SUN was 8.2 vs. 13.8 months (1-sided p=0.96). There were no statistically significant differences in ORR or OS between the arms. AEs were in line with previous studies. Conclusions: CABO was not superior to SUN for metastatic NCCRCC in this study. Both arms had high rates of stable disease or better. Despite stratification by PRCC or NPRCC, there were major differences in NPRCC subtypes between the arms that may have impacted the results. More pts with chromophobe histology, an often indolent subtype, received SUN while all pts with MiT family translocation, a relatively aggressive subtype, received CABO. Permitted SUN dose modifications may have also influenced outcomes. While the PAPMET study showed CABO to be superior to SUN for PRCC, optimal treatments for rare, NPRCC remain a pressing need. Clinical trial information: NCT03541902 . [Table: see text]

AbstractBackgroundUropathogen resistance, fluoroquinolone‐resistance (FQR), and extended spectrum beta‐lactamase (ESBL), has been observed to be emerging worldwide with prevalences above recommended thresholds for routine empirical treatment. The primary aim of our study was to determine the prevalence of FQR from a geographically diverse sample of United States emergency departments (EDs).MethodsWe conducted a multi‐center, observational cohort study using a network of 15 geographically diverse US EDs. All patients ≥18 years of age with the primary or secondary diagnosis of urinary tract infection (UTI) in the ED identified using International Classification of Diseases (ICD‐10) diagnosis code of cystitis, pyelonephritis, or UTI from 2018 to 2020 were included. We calculated descriptive statistics for uropathogens and susceptibilities. Logistic regression analysis was used to identify antimicrobial resistance risk factors associated with FQR Escherichia coli.ResultsAmong 3779 patients who met inclusion criteria, median age was 62.9 years (interquartile range [IQR]: 41–77.6) and 76.3% were female. The most common diagnoses were complicated (41.2%) and uncomplicated cystitis (40.3%). E. coli was the most common pathogen (63.2%), followed by Klebsiella pneumoniae (13.2%) and Enterococcus species (5.8%). Across all sites, overall E. coli FQ‐resistance prevalence was 22.1%, ranging from 10.5 to 29.7% by site. The prevalence of ESBL‐producing uropathogen was 7.4%, ranging from 3.6% to 11.6% by site. Previous IV or oral antimicrobial use in the past 90‐days and history of a multi‐drug resistant pathogen were associated with FQ‐resistant E. coli (odds ratio [OR] 2.68, 95% confidence interval [CI]: 2.04–3.51, and OR 6.93, 95% CI: 4.95–9.70, respectively). Of the patients who had FQ‐resistant E. coli or an ESBL‐producing uropathogen isolated, 116 (37.1%) and 61 (36.7%) did not have any documented risk factors for resistance.ConclusionFQ‐resistant E. coli is widely prevalent across US sites highlighting the need for ongoing monitoring of antimicrobial resistance and, at some locations, modification of empirical treatments.

Background There is no effective systemic therapy for metastatic adrenal cortical carcinoma (ACC) after failure of platinum-based chemotherapy. The efficacies of single-agent oral multikinase inhibitors (MKIs) or salvage immune checkpoint inhibitors (CPIs) have been very limited. It is unknown whether combining CPIs, such as pembrolizumab (PEM), with other therapies, such as MKIs, could yield higher response rates in ACC, yet this combination has shown promise in other cancers. Herein, we describe the first case series using PEM in combination with the MKI lenvatinib (LEN) in patients with progressive, metastatic ACC. Methods A retrospective case series describing the use of LEN/PEM as salvage therapy in patients with progressive/metastatic ACC. Results Eight patients were treated with the LEN/PEM combination therapy. Half were female, and the median age at time of diagnosis was 38 years (range 21–49). Three (37.5%) patients had hormonally active ACC. The median number of prior lines of systemic therapy was 4 (range 2–9). Six (75%) patients had had disease progression on prior CPIs and five (62.5%) patients had progressed on prior MKI therapy. The median progression-free survival was 5.5 months (95% CI 1.8–not reached) and median duration of therapy was 8.5 months (range 2–22). Two (25%) patients had a partial response, one (12.5%) patient had stable disease, and five (62.5%) patients had progressive disease. None of the eight patients stopped therapy because of adverse events. Conclusions In our small cohort of heavily pretreated patients with ACC, the combination of LEN/PEM was associated with objective responses in a subset of patients without significant toxicity. This combination should be formally investigated in phase II clinical trial with robust correlative studies to identify predictors for response.

Abstract Background: The methylthioadenosine phosphorylase (MTAP) gene encodes an essential enzyme for the salvage pathway of adenosine synthesis and is frequently lost in different types of cancer including urothelial bladder carcinoma. Therefore, MTAP-deficient tumors are theoretically very sensitive to anti-folate agents such as pemetrexed that can effectively block the de novo pathway of adenosine synthesis and as a result, create a state of synthetic lethality. We thus hypothesize that tumor MTAP gene deficiency is associated with response to pemetrexed therapy in bladder cancer. Methods: In this study, we investigated MTAP gene deficiency rates in the TCGA database and confirmed MTAP protein loss by immunohistochemistry using a tumor tissue microarray containing bladder tumor tissues from 151 patients. We then performed in vitro and in vivo studies using MTAP-proficient and MTAP-deficient human bladder cancer cell lines. Functional loss of MTAP was verified with mass spectrometry, which detects its substrate methylthioadenosine (MTA) levels. We also correlated these pre-clinical studies with clinical response data on patients with metastatic bladder cancer treated with pemetrexed. Results: We identified that 27.8% bladder cancer patients have MTAP protein deficiency, which is consistent with exome sequencing data from the TCGA database. In vitro data showed MTAP-deficient human bladder cancer cell lines were significantly more sensitive to pemetrexed, with IC50 at least 40 times lower than MTAP-proficient cell lines. Subsequent knockdown of the MTAP gene in MTAP-proficient cell lines increased sensitivities to pemetrexed treatment. Consistent with the in vitro data, pemetrexed significantly inhibited the growth of MTAP-deficient or knockdown xenograft tumors but not MTAP-proficient tumors. Furthermore, 4 of 4 (100%) patients with MTAP-deficient metastatic bladder cancer responded to pemetrexed treatment, whereas only 1 of 11 (9%) patients with MTAP-proficient metastatic bladder cancer responded to pemetrexed. Conclusion: Our data demonstrate that MTAP gene loss in urothelial bladder cancer leads to a metabolic state of synthetic lethality with pemetrexed therapy. Therefore, bladder tumor MTAP loss should be further investigated as a potential biomarker for selection of patients for anti-folate therapy. Citation Format: Jianfeng Chen, Omar Alhalabi, Guangchun Han, Wei-Lien Wang, Xin-Qiao Zhang, Jian H. Song, Lidia P. Lopez, Sumankalai Ramachandran, Anh G. Hoang, Tyrone Garnett, Matthew Campbell, Amishi Y. Shah, Jennifer Wang, Arlene O. Siefker-Radtke, Shi-Ming Tu, Mark Titus, Charles C. Guo, Gary E. Gallick, Eleni Efstathiou, William F. Benedict, Christopher J. Logothetis, Thai H. Ho, Linghua Wang, Jianjun Gao. MTAP gene deficiency creates vulnerability to anti-folate therapy in urothelial bladder 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 385.

4521 Background: The MTAP gene encodes an essential enzyme for the salvage pathway of nucleotide synthesis and is frequently deleted in UBC. Anti-folate agents such as pemetrexed can effectively inhibit the de novo pathway of nucleotide synthesis and as a result, create a synthetic lethality in MTAP deficient UBC. We hypothesize that MTAP gene loss correlates with enhanced response to pemetrexed in UBC. Methods: We investigated MTAP gene deletion rates in the TCGA database and determined MTAP protein loss rates by immunohistochemistry (IHC) using a UBC tissue microarray (TMA) from 151 patients (pts). We then performed in vitro and in vivo studies using MTAP proficient and MTAP deficient bladder cancer cell lines. At the clinical level, we performed a retrospective analysis based on MTAP status of pts treated with pemetrexed as 2nd line at our institution between 2014 and 2018. We are now enrolling pts in a single-arm, open-label, phase II clinical trial (NCT02693717) with pemetrexed in pts with MTAP deficient UBC. Results: Per our TCGA and TMA IHC analyses, MTAP deficiency rate was 25.9% and 27.8%, respectively. MTAP deficient UBC cell lines were at least 40 times more sensitive to pemetrexed than MTAP proficient lines. Knockdown of the MTAP gene increased apoptosis rate by pemetrexed from approximately 20% to 60%. Additionally, pemetrexed significantly inhibited the growth of MTAP deficient or knockdown xenograft tumors but not MTAP proficient tumors. Retrospective analysis of 12 pts using RECIST criteria indicated that all 4 MTAP deficient UBC pts responded to pemetrexed whereas only 1 of 8 (12.5%) MTAP proficient UBC pts responded. Of the 6 pts enrolled on the clinical trial, 3 (50%) had complete or partial response, 1 had stable disease, 1 was not evaluable and 1 had disease progression. Combined analysis of the entire experience demonstrates a higher response rate in MTAP deficient UBC (70%) as compared to MTAP proficient UBC (12.5%). Conclusions: Our preclinical and clinical data demonstrate that MTAP loss in UBC leads to a state of synthetic lethality when treated with pemetrexed and should be further investigated as a novel biomarker to predict response to anti-folate agents.

4519 Background: Tandem HDC with carbo/etoposide (CE) is curative for a portion of relapsed GCT pts. However, outcomes of refractory or high-risk relapsed pts remain poor. We tested a new HDC regimen of GemDMC, based on DNA damage repair inhibition. We combined BEV with HDC given their potential synergy and the high vascularity of GCT metastases. Methods: Eligibility: Intermediate (int)/high-risk (Beyer Model), creatinine ≤1.8 mg/dL and adequate organ function. HDC included BEV (5 mg/kg) preceding GemDMC (HDC #1) and ifosfamide/CE (ICE) (HDC #2). Following accrual of 42 pts, we amended the trial omitting BEV. The trial was powered to distinguish a target 50% 2-yr RFS from an expected 25% in this population. Results: We enrolled 69 male pts in cohorts 1 (BEV, N=42) and 2 (no BEV, N=27) (Table). Pts were heavily pretreated and most had refractory tumors. Main AE: mucositis and renal (4 HDC-related deaths in cohort 1, 1 in cohort 2). Tumor markers normalized in 90% pts with active tumors at HDC. After HDC, 19 pts were in CR and 28 in PRm- (of these, 22 had residual lesions resected with no viable tumor found in 20/22, 2 xRT, 4 monitored). Median f/u = 39 (2-105) mo. The 2-yr RFS rates in cohorts 1 and 2 = 52% and 78%, respectively. Their respective 2-yr OS rates = 55% and 81%. Conclusions: Sequential HDC with GemDMC–ICE shows encouraging outcomes in heavily pretreated and refractory GCT, exceeding the anticipated results. Addition of BEV increases toxicity but not tumor control. Clinical trial information: NCT00936936. [Table: see text]

Abstract Background: Pembrolizumab (Pembro), an anti-PD-1 immune checkpoint inhibitor, has been approved for the treatment of a variety of cancers including melanoma, non-small cell lung cancer, head and neck squamous cell carcinoma, and urothelial carcinoma. Pembro was recently evaluated in HER2- breast cancer patients in the neoadjuvant I-SPY 2 TRIAL and graduated in the triple negative (TN), HR+HER2-, and HER2- signatures. HER2- patients were randomized to receive Pembro+paclitaxel followed by doxorubicin/cyclophosphamide (P+T -> AC) vs. T -> AC. We and others have shown that TN breast cancers tend to have high numbers of immune infiltrates, including T cells and tumor associated macrophages (TAMs). We evaluated expression signatures representing 14 immune cell types (TILs, T cells, CD8 T cells, exhausted T cells, Th1, Tregs, cytotoxic cells, NK, NK CD56dim, dendritic cells, mast cells, B cells, macrophages, and neutrophils) as specific predictors of response to Pembro. Methods: Data from 248 patients (Pembro: 69; controls: 179) were available. Pre-treatment biopsies were assayed using Agilent gene expression arrays. Signature scores are calculated by averaging cell type specific genes. All I-SPY 2 qualifying biomarker analyses follow a pre-specified analysis plan. We used logistic modeling to assess biomarker performance. A biomarker is considered a specific predictor of Pembro response if it associates with response in the Pembro arm but not the control arm, and if the biomarker x treatment interaction is significant (likelihood ratio test, p<0.05). This analysis is also performed adjusting for HR status as covariates, and within receptor subsets. For successful biomarkers, we use Bayesian modeling to estimate the pCR rates of 'predicted sensitive' patients in each arm. Our statistics are descriptive rather than inferential and do not adjust for multiplicities of other biomarkers outside this study. Results: 10 out of the 14 cell-type signatures tested are associated with response in the Pembro arm. Higher expression levels of 9 of these cell-type signatures are associated with higher pCR rates (T cells, exhausted T cells, Th1, cytotoxic cells, NK, NK CD56dim, dendritic cells, B cells, and macrophages), whereas higher mast cell signature expression is associated with non-pCR. Interestingly, many of these same signatures also associate or trend towards association with response in the control arm; and in a model adjusting for HR status, only 3 of these signatures (Th1, B cells and dendritic cells) show significant interaction with treatment. Within the whole population and the TN subtype, the dendritic cell signature is the strongest predictor of specific response to Pembro (OR/1SD: 4.04 and 4.4, LR p < 0.001 overall and in TN). Although other immune signatures (T cells, exhausted T cells, NK, and macrophages) also associate with response in the Pembro arm in the TN subtype, only the dendritic cell and Th1 signatures have a significant interaction with treatment. In contrast, in the HR+HER2- subtype, only 3 signatures (Th1, B cells, and mast cells) associate with response to Pembro; but none of these signatures have significant interaction with treatment. Of note, in both the Pembro and control arms, HR+HER2- patients with higher average mast cell marker expression have lower pCR rates (OR/1SD: 0.33 and 0.51, LRp: 0.006 and 0.04 in Pembro and control arm). Conclusion: As expected, multiple immune cell expression signatures are predictive of response in the Pembro arm; but only dendritic cells and Th1 cells are specific to Pembro in both the population as a whole and the TN subtype. Interestingly, the presence of mast cells may impede response, especially in HR+HER2- patients. Correlation of these signatures with multiplex-IF immune markers is pending. Citation Format: Campbell M, Yau C, Borowsky A, Vandenberg S, Wolf D, Rimm D, Nanda R, Liu M, Brown-Swigart L, Hirst G, Asare S, van't Veer L, Yee D, DeMichele A, Berry D, Esserman L. Analysis of immune infiltrates (assessed via multiplex fluorescence immunohistochemistry) and immune gene expression signatures as predictors of response to the checkpoint inhibitor pembrolizumab in the neoadjuvant I-SPY 2 trial [abstract]. In: Proceedings of the 2017 San Antonio Breast Cancer Symposium; 2017 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2018;78(4 Suppl):Abstract nr PD6-08.