Citations

Abstract To repurpose therapeutics for fibrolamellar carcinoma (FLC), we developed and validated patient-derived xenografts (PDX) from surgical resections. Most agents used clinically and inhibitors of oncogenes overexpressed in FLC showed little efficacy on PDX. A high-throughput functional drug screen found primary and metastatic FLC were vulnerable to clinically available inhibitors of TOPO1 and HDAC and to napabucasin. Napabucasin's efficacy was mediated through reactive oxygen species and inhibition of translation initiation, and specific inhibition of eIF4A was effective. The sensitivity of each PDX line inversely correlated with expression of the antiapoptotic protein Bcl-xL, and inhibition of Bcl-xL synergized with other drugs. Screening directly on cells dissociated from patient resections validated these results. This demonstrates that a direct functional screen on patient tumors provides therapeutically informative data within a clinically useful time frame. Identifying these novel therapeutic targets and combination therapies is an urgent need, as effective therapeutics for FLC are currently unavailable. Significance: Therapeutics informed by genomics have not yielded effective therapies for FLC. A functional screen identified TOPO1, HDAC inhibitors, and napabucasin as efficacious and synergistic with inhibition of Bcl-xL. Validation on cells dissociated directly from patient tumors demonstrates the ability for functional precision medicine in a solid tumor. This article is highlighted in the In This Issue feature, p. 2355

Abstract Adenosquamous cancer of the pancreas (ASCP) is a subtype of pancreatic cancer that has a worse prognosis and greater metastatic potential than the more common pancreatic ductal adenocarcinoma (PDAC) subtype. To distinguish the genomic landscape of ASCP and identify actionable targets for this lethal cancer, we applied DNA content flow cytometry to a series of 15 tumor samples including five patient-derived xenografts (PDX). We interrogated purified sorted tumor fractions from these samples with whole-genome copy-number variant (CNV), whole-exome sequencing, and Assay for Transposase-Accessible Chromatin using sequencing (ATAC-seq) analyses. These identified a variety of somatic genomic lesions targeting chromatin regulators in ASCP genomes that were superimposed on well-characterized genomic lesions including mutations in TP53 (87%) and KRAS (73%), amplification of MYC (47%), and homozygous deletion of CDKN2A (40%) that are common in PDACs. Furthermore, a comparison of ATAC-seq profiles of three ASCP and three PDAC genomes using flow-sorted PDX models identified genes with accessible chromatin unique to the ASCP genomes, including the lysine methyltransferase SMYD2 and the pancreatic cancer stem cell regulator RORC in all three ASCPs, and a FGFR1-ERLIN2 fusion associated with focal CNVs in both genes in a single ASCP. Finally, we demonstrate significant activity of a pan FGFR inhibitor against organoids derived from the FGFR1-ERLIN2 fusion–positive ASCP PDX model. Our results suggest that the genomic and epigenomic landscape of ASCP provide new strategies for targeting this aggressive subtype of pancreatic cancer. Significance: These data provide a unique description of the ASCP genomic and epigenomic landscape and identify candidate therapeutic targets for this dismal cancer.

Abstract Background: Upamostat is an orally available small molecule serine protease inhibitor that is a highly potent inhibitor of trypsin 1, trypsin 2 and trypsin 3 (PRSS1/2/3) as well as urokinase-type plasminogen activator (uPA) which are expressed in many cancers and mediate cell migration, invasion and tissue remodeling. Opaganib (ABC294640), a novel, orally available small molecule is a specific inhibitor of sphingosine kinase 2 (SPHK2), which phosphorylates sphingosine to sphingosine-1-phosphate (S-1-P). While proliferation induced by S-1-P is regulated by both sphingosine kinase 1 (SPHK1) and SPHK2, SPHK2 appears to be more involved in cancer. We aimed to investigate the potential antitumor effect of upamostat and opaganib, individually and in combination, on cholangiocarcinoma (CCA) patient derived xenografts (PDX) in nude mice. Methods: PAX165, a PDX from a surgically resected CCA, expresses substantial levels of SPHK2, PRSS1, PRSS2 and PRSS3. 4 groups of 18 mice were treated with either drug or both. Mouse weights and tumor volumes were measured. In addition, experiments were conducted using the chorioallantoic membrane (CAM) of chicken embryos. Results: Table 1 shows the average tumor size for the control, upamostat, opaganib, and upamostat+opaganib groups at the study end point (Day 42). Tumor volumes in the upamostat, opaganib, and upamostat+opagnib groups were significantly decreased compared to the control group. The CAM experiments are ongoing and will be presented at the AACR Annual Meeting. Change in tumor volumes (mean) of CCA PDX after opaganib, upamostat or combination treatmentControlOpaganibUpamostatOpaganib+UpamostatPre-treatment129.9128.7118.8126.8Day 42198.6102.093.3186.09Percent change Day 0-42+53%-21%-21%-32%P value vs. control0.00020.00100.0008 Conclusion: This preclinical study demonstrated that upamostat and opaganib resulted in tumor regression in mice. Body weights of the mice showed no significant inter- or intra- group differences. The combination of upamostat and opaganib treatment showed greater regression compared to either upamostat or opaganib alone. Studies are underway to identify the molecular mechanisms of their interaction. Citation Format: Faizal Z. Asumda, Mohamed A. Hassan, Yo Han Kim, Nellie A. Campbell, Xin Luo, Daniel R. O'Brien, Sarah A. Buhrow, Joel M. Reid, Michael J. Moore, Vered Katz Ben-Yair, Reza Fathi, Mark L. Levitt, Fabrice Lucien-Matteoni, Jennifer L. Leiting, Mark J. Truty, Lewis R. Roberts. Effects of upamostat and opaganib on cholangiocarcinoma patient derived xenografts [abstract]. In: Proceedings of the Annual Meeting of the American Association for Cancer Research 2020; 2020 Apr 27-28 and Jun 22-24. Philadelphia (PA): AACR; Cancer Res 2020;80(16 Suppl):Abstract nr 3078.

Abstract Background It is unclear whether results from recent trials of resectable pancreatic ductal adenocarcinoma (PDAC) are generalizable to older patients, who are underrepresented. We aimed to evaluate outcomes of surgery and of neoadjuvant and adjuvant therapy in older patients with resectable PDAC. Patients and Methods We included patients aged ≥65 years with upfront resectable PDAC from a prospectively maintained pancreatic cancer registry from 2007 to 2016. Patients were stratified into ages 65–75 and 75+ years. Overall survival (OS) was assessed in treatment comparisons: (A) surgery (n = 636) versus nonsurgical (n = 178), (B) neoadjuvant therapy (n = 139) versus upfront surgery (n = 497), and (C) adjuvant therapy (n = 379) versus surgery alone (n = 118). We compared neoadjuvant (n = 139) versus adjuvant therapy (n = 379) in an exploratory analysis. Results Nine hundred and three patients had a median age of 73.7 (range, 65–96.6) years. Median OS was 26.6 versus 11.9 months (adjusted hazard ratio [HRadj], 0.4; 95% confidence interval [CI], 0.31–0.52; p < .001) in Comparison A groups, 30.7 versus 25.8 months (HRadj, 0.69; 95% CI, 0.49–0.96; p = .03) in Comparison B groups, and 26.9 versus 17.4 months (HRadj, 0.62; 95% CI, 0.44–0.88; p = .008) in Comparison C groups, respectively. OS benefit in these treatment comparisons was present in age group 75+ with HRadj 0.24 (95% CI, 0.16–0.36; p < .001) in Comparison A and HRadj 0.52 (95% CI, 0.27–1; p = .049) in Comparison B, but not in Comparison C with HRadj 0.68 (95% CI, 0.43–1.08; p = .1). Statistically comparable median OS of patients who received neoadjuvant or adjuvant therapy stratified by age groups was observed. Conclusion Older patients with resectable PDAC who received surgery, neoadjuvant therapy, or adjuvant therapy appeared to have improved survival outcomes compared with those who did not receive such treatment. Implications for Practice Older patients with resectable pancreatic ductal adenocarcinoma (PDAC) in general are underrepresented in large clinical trials and less well studied in terms of the role of surgery, neoadjuvant therapy, and adjuvant therapy. This study collected data on older patients with resectable PDAC from a prospectively maintained single-institutional pancreatic cancer registry of a tertiary referral center from 2007 to 2016. It was found that, with multidisciplinary evaluation, older patients with resectable PDAC who received surgery, neoadjuvant therapy, or adjuvant therapy appeared to have improved survival outcomes compared with those who did not receive such treatment. These results are of substantial importance to practitioners who treat older patients, who are traditionally underrepresented in most clinical trials.

706 Background: In recent years, there has been a shift towards neo-adjuvant treatment (NAT) of non-metastatic pancreas cancer in the hopes of improving negative margin rate, lymph node negativity, recurrence and survival. Even patients deemed resectable based on NCCN criteria are receiving NAT but data for these patients remains limited. This current study evaluated the outcomes of patients diagnosed with resectable pancreatic adenocarcinoma. Methods: Patients were retrospectively identified through the Mayo Clinic, Rochester SPORE pancreatic cancer registry as well as search of the electronic medical record via Advanced Cohort Explorer from May 2011 to 2016. Baseline demographics, tumor characteristics, treatments rendered, and outcomes were collected. Variables were analyzed for association with recurrence from time of surgery and survival from time of diagnosis using Kaplan-Meier curves and Cox proportional hazards regression. Results: A total of 520 patients with resectable pancreatic adenocarcinoma were identified. 72 patients received upfront chemotherapy with 44 (61.1%) proceeding to surgical resection. 62 patients received upfront chemotherapy followed by radiation with 33 (53.2%) proceeding to surgical resection. 12 patients received upfront radiation alone with 7 (58.3%) proceeding to surgical resection. 374 patients did not receive any NAT with 293 (78.3%) proceeding to surgical resection. In total, 377 (72.5%) went to resection. Median time to recurrence from surgery was 27.7 months vs. 21.7 months for NAT and upfront resection, respectively (HR 0.87, 95% CI 0.60-1.72, p = 0.48). Median overall survival from diagnosis for those receiving NAT was 40.6 months vs. 24.7 months for those receiving upfront resection (HR 0.62, 95% CI 0.41-0.92, p = 0.02). Conclusions: This study shows an approximate 16 month improvement in overall survival of patients receiving upfront NAT for resectable pancreatic adenocarcinoma. This might be due to a better selection of patients. It also highlights that not all patients with resectable cancer undergo resection. Further studies are warranted to identify why resectable patients are not proceeding to resection and which specific NAT approaches benefit patients the most.

AbstractBackground and ObjectivesConclusive evidence in favor of neoadjuvant therapy for those with non‐metastatic pancreatic ductal adenocarcinoma (PDAC) is still lacking. The objective of this study was to evaluate the survival benefit of neoadjuvant therapy vs upfront surgery for patients with non‐metastatic PDAC.MethodsThe study involved 565 patients undergoing neoadjuvant therapy or upfront surgery as the primary treatment for PDAC. Propensity score matching was performed between the neoadjuvant therapy group (NAT group) and the upfront surgery group (UFS group) using 20 clinical variables at diagnosis. Overall survival and surgical pathology were compared between the two treatment groups on an intent‐to‐treat basis.ResultsIn the matched cohort, the NAT group (n = 91) had a longer median overall survival than the UFS group (n = 91) (23.1 months vs 18.5 months, P = .043). The rate of patients undergoing surgical resection was lower in the NAT group (58% vs 80%, P = .001). Regarding surgical pathology, the NAT group had smaller tumor size (2.8 cm vs 4.0 cm, P = .001), lower incidence of positive surgical margins (8% vs 30%, P < .002), and less lymph node metastasis (45% vs 78%, P < .001).ConclusionsThe strategy of neoadjuvant therapy before surgical resection appears to offer pathologic effect and survival benefit for the patients presenting with non‐metastatic PDAC.

355 Background: In this study, we sought to determine the prognostic factors impacting survival of patients with NELM who underwent LT at Mayo Clinic. Methods: We performed a three-site retrospective analysis of patients with unresectable NELM treated with LT from 1990 -2017. Cases were identified from clinical databases at Mayo Clinic. Data on demographics, timing of diagnosis and transplant, extent of liver involvement, and tumor grade, were extracted. Extent of liver involvement was calculated using previously validated standardized volumetry with high defined as > 25% increase in the weight of the extracted liver at the time of the transplant as compared to the standard liver volume. Survival was calculated using the Kaplan–Meier method. Results: We identified 37 patients. Median age at LT was 47 (range 17.0-64.0), male: female (73% vs. 27%, respectively). Primary tumor site was in the pancreas in 51.3% and in the small bowels in 43.2%; 78.4% had NELM at presentation. While primary tumor resection was done at the time of LT in 5 (13.9%) cases, most patients (80.6%) had ˃6-months interval between primary tumor resection and LT surgery. Prior to LT, 25 (74.3%) patients received somatostatin analogues and 18 (61.3%) had liver-directed therapy. Median time from diagnosis to transplant was 33.6 months (0-246). High extent of liver involvement was identified in 12 patients (33.3%). Disease-Free Survival (DFS) at 3, 5, and 10 years was 56.8%, 43.1%, and 22.4% respectively. Overall-survival (OS) at 3, 5, and 10 years was 86.9%, 79.6%, and 52.6% respectively. High extent of liver involvement at the time of transplantation was associated with inferior DFS and OS and patients˃45 years-old at the time of transplantation had worse DFS. Patients whose disease met the OPTN (Organ Procurement and Transplantation Network) criteria for NELM transplantation had significantly better DFS and OS with median 10-year OS of 80.7 % vs. 17%. Conclusions: LT is a reasonable therapeutic option for selected patients with unresectable NELM with 10-year OS of 52.6%. High extent of liver involvement was associated with worse long-term outcomes while meeting OPTN criteria resulted in best outcomes.

Perioperative radiation therapy (RT) has been associated with reduced local recurrence in patients with retroperitoneal sarcomas (RPS); however, selection criteria remain unclear. We hypothesized that perioperative RT would improve survival in patients with RPS and would be associated with pathological factors. The National Cancer Database (NCDB) from 2004 to 2012 was reviewed for patients with nonmetastatic RPS undergoing curative intent resection. Tumor size was dichotomized at 15 cm based on 8th edition American Joint Committee on Cancer (AJCC) staging. Patients with the highest comorbidity score were excluded. Unadjusted Kaplan–Meier and adjusted Cox proportional hazards modeling analyzed overall survival (OS). Multivariable logistic regression modeled margin positivity. A total of 2,264 patients were included; 727 patients (32.1%) had perioperative radiation in whom 203 (9.0%) had radiation preoperatively. Median (IQR) RPS size was 17.5 [11.0–27.0] cm. Histopathology was high grade in 1048 patients (43.7%). Multivariable analysis revealed that perioperative radiation was independently associated with decreased mortality (HR 0.72, 95% confidence intervals (CIs) 0.62–0.84,p<0.001), and preoperative RT was associated with reduced margin positivity (HR 0.72, 95% CI 0.53–0.97,p=0.032). Stratified survival analysis showed that radiation was associated with prolonged median OS for RPS that were high-grade (64.3 vs. 43.6 months,p<0.001), less than 15 cm (104.1 vs. 84.2 months,p=0.007), and leiomyosarcomatous (104.8 vs. 61.8 months,p<0.001). Perioperative radiation is independently associated with decreased mortality in patients with high-grade, less than 15 cm, and leiomyosarcomatous tumors. Preoperative radiation is independently associated with margin-negative resection. These data support the selective use of perioperative radiation in the multidisciplinary management of RPS.