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Purpose:Pancreatic neuroendocrine tumors (pNETs) are uncommon malignancies noted for their propensity to metastasize and comparatively favorable prognosis. Although both the treatment options and clinical outcomes have improved in the past decades, most patients will die of metastatic disease. New systemic therapies are needed.Experimental Design:Tissues were obtained from 43 patients with well-differentiated pNETs undergoing surgery. Gene expression was compared between primary tumors versus liver and lymph node metastases using RNA-Seq. Genes that were selectively elevated at only one metastatic site were filtered out to reduce tissue-specific effects. Ingenuity pathway analysis (IPA) and the Connectivity Map (CMap) identified drugs likely to antagonize metastasis-specific targets. The biological activity of top identified agents was tested in vitro using two pNET cell lines (BON-1 and QGP-1).Results:A total of 902 genes were differentially expressed in pNET metastases compared with primary tumors, 626 of which remained in the common metastatic profile after filtering. Analysis with IPA and CMap revealed altered activity of factors involved in survival and proliferation, and identified drugs targeting those pathways, including inhibitors of mTOR, PI3K, MEK, TOP2A, protein kinase C, NF-kB, cyclin-dependent kinase, and histone deacetylase. Inhibitors of MEK and TOP2A were consistently the most active compounds.Conclusions:We employed a complementary bioinformatics approach to identify novel therapeutics for pNETs by analyzing gene expression in metastatic tumors. The potential utility of these drugs was confirmed by in vitro cytotoxicity assays, suggesting drugs targeting MEK and TOP2A may be highly efficacious against metastatic pNETs. This is a promising strategy for discovering more effective treatments for patients with pNETs.

Supplementary table 4

The increased incidence and prevalence of neuroendocrine tumors (NETs) over the past few decades has been accompanied by an improvement in overall survival. There are differences in the management of small bowel NETs versus pNETs. The management of all patients with NETs must be individualized based on patient characteristics as well tumor-related factors. This article reviews the role of somatostatin analogues, historical results with chemotherapy in gastroenteropancreatic NETs (GEPNETs), and more recent evidence for the use of cytotoxic chemotherapy in GEPNETs. The article also discusses molecular targeted therapies approved for use in GEPNETs and some ongoing clinical trials.

80 Background: Incidence of colorectal cancer (CRC) among adolescents and young adults (AYA) is increasing. A significant proportion of adolescents and young adults (AYA) with colorectal cancer (CRC) lack traceable genetic risk factors. We sought to study the impact of lifestyle-related risk factors on the incidence and mortality of CRC in these patients. Methods: We extracted data on crude incidence and mortality rates of CRC (reported per 100,000 population) for ages 15-39 years in all 50 U.S. states and District of Columbia from the Center for Disease Control (CDC) WONDER database (1999-2018). Data on risk factors such as obesity, physical activity, alcohol and tobacco abuse and nutrition were obtained from the Behavioral Risk Factor Surveillance System (BRFSS, 2020). Correlations were analyzed using Pearson’s co-efficient. p < 0.05 was considered statistically significant. Statistical analysis was performed using VassarStats. Results: Median crude incidence and mortality rates of CRC in AYA in the US from 1999-2018 were 3.8 (IQR 3.2, 4.4) and 0.7 (IQR 0.5,0.9) per 100,000 population respectively. States with higher age-adjusted prevalence of obesity per 100,000 had higher incidence (r = 0.36, p = 0.01) and mortality rates (r = 0.49, p = 0.0002) of CRC in AYA population. States with a higher age-adjusted prevalence of adherence to recommended weekly aerobic activity had lower incidence (r = -0.4515, p = 0.001) and mortality (r = -0.569, p < 0.0001) rates. While states with higher age-adjusted prevalence of tobacco abuse had higher incidence rate of CRC (r = 0.33, p = 0.02), there was no correlation with mortality rates (r = 0.24, p = 0.09). Higher prevalence of alcohol consumption was associated with decreased mortality rate (r = -0.44, p = 0.001), with no impact on incidence rate (r = -0.16, p = 0.26). States with lower daily consumption of fruits had higher incidence (r = 0.37, p = 0.01) and mortality rates (r = 0.59, p < 0.0001). No correlation of daily consumption of vegetables with incidence (r = -0.1516, p = 0.29) and mortality (r = 0.18, p = 0.22) rates was noted. Conclusions: In the current analysis, higher prevalence of obesity, lower rates of aerobic activity and lower daily consumption of fruits were strongly associated with increased incidence and mortality rates. The impact of tobacco abuse and alcohol consumption was more variable. Apart from improving access to genetic testing and counseling, efforts aimed at mitigating the rise of CRC incidence among AYA should also focus on traditional lifestyle-related risk factors.

BACKGROUND: Management of duodenal neuroendocrine tumors (DNETs) is not standardized, with smaller lesions (

Through our involvement in KEYNOTE-059, we unexpectedly observed durable responses in two patients with metastatic gastroesophageal adenocarcinoma (mGEA) who received ramucirumab (anti-VEGFR-2)/paclitaxel after immune checkpoint inhibition (ICI). To assess the reproducibility of this observation, we piloted an approach to administer ramucirumab/ paclitaxel after ICI in more patients, and explored changes in the immune microenvironment. Nineteen consecutive patients with mGEA received ICI followed by ramucirumab/paclitaxel. Most (95%) did not respond to ICI, yet after irRECIST-defined progression on ICI, all patients experienced tumor size reduction on ramucirumab/paclitaxel. The objective response rate (ORR) and progression-free survival (PFS) on ramucirumab/paclitaxel after ICI were higher than on the last chemotherapy before ICI in the same group of patients (ORR, 58.8% vs 11.8%; PFS 12.2 vs 3.0 months; respectively). Paired tumor biopsies examined by imaging mass cytometry showed a median 5.5-fold (range 4–121) lower frequency of immunosuppressive forkhead box P3+ regulatory T cells with relatively preserved CD8+ T cells, post-treatment versus pre-treatment (n = 5 pairs). We then compared the outcomes of these 19 patients with a separate group who received ramucirumab/paclitaxel without preceding ICI (n = 68). Median overall survival on ramucirumab/paclitaxel was longer with (vs without) immediately preceding ICI (14.8 vs 7.4 months) including after multivariate analysis, as was PFS. In our small clinical series, outcomes appeared improved on anti-VEGFR-2/paclitaxel treatment when preceded by ICI, in association with alterations in the immune microenvironment. However, further investigation is needed to determine the generalizability of these data. Prospective clinical trials to evaluate sequential treatment with ICI followed by anti-VEGF(R)/taxane are underway.

Patients with neuroendocrine tumor liver metastases (NETLMs) may develop carcinoid syndrome, carcinoid heart disease, or other symptoms from overproduction of hormones. Hepatic resection and cytoreduction is the most direct treatment of NETLMs in eligible patients, and cytoreduction improves symptoms, may reduce the sequelae of carcinoid syndrome, and extends survival. Parenchymal-sparing procedures, such as ablation and enucleation, should be considered during cytoreduction to maximize treatment of multifocal tumors while preserving healthy liver tissue. For patients with large hepatic tumor burdens, high-grade disease, or comorbidities precluding surgery, liver-directed and systemic therapies can be used to palliate symptoms and improve progression-free survival.

BACKGROUND: Tumor biomarkers (TBMs) reflect disease burden and correlate with survival for small bowel neuroendocrine tumors (SBNETs). This study sought to determine the performance of chromogranin A (CgA), pancreastatin (PST), neurokinin A (NKA), and serotonin (5HT) during follow-up assessment of resected SBNETs. METHODS: An institutional database identified patients undergoing surgery for SBNETs. Tumor biomarker levels were assessed as categorical (normal vs elevated) and continuous variables for association with progression-free survival (PFS) and overall survival (OS) via the Kaplan-Meier method with Cox multivariable models adjusted for confounders. Sensitivity, specificity, and predictive values of TBM levels in identifying imaging-confirmed progression were calculated. RESULTS: In 218 patients (44 % female, 92 % node+, 73 % metastatic, 97 % G1 or G2), higher levels of CgA, PST, NKA, and 5HT correlated with higher-grade and metastatic disease at presentation (p < 0.05). Elevated pre- and postoperative CgA, PST, and NKA correlated with lower PFS and OS (p < 0.05; median follow-up period, 49.6 months). Normal CgA, PST, and NKA were present in respectively 20.3 %, 16.9 %, and 72.6 % of the patients with progression, whereas elevated levels were present in respectively 69.5 %, 24.8 %, and 1.3 % of the patients without progression. Using TBMs to determine progression showed superiority of PST (78.9 % accuracy) over CgA (63.3 % accuracy) or CgA and PST together (60.3 % accuracy). CONCLUSION: Although specific for progression, NKA was rarely elevated, limiting its usefulness. Pre- and postoperative PST and CgA correlated with disease burden and survival, with PST providing better discrimination of outcomes. During the follow-up period, use of PST most accurately detected progression. These results suggest that PST should replace CgA for SBNET surveillance.

Carcinoid syndrome (CS), characterized by diarrhea and flushing, is present in 20% of patients with neuroendocrine tumors at diagnosis and becomes more frequent with progression. The diarrhea of CS is caused mainly by tumoral secretion of serotonin. It may not be fully controlled by somatostatin analogs, the currently indicated drugs for symptomatic relief. Telotristat ethyl is a novel inhibitor of tryptophan hydroxylase, the rate-limiting enzyme in serotonin biosynthesis. Administration of the drug decreases diarrhea in patients with CS. Telotristat ethyl was approved in February 2017 (USA) and September 2017 (European Commission) for the treatment of CS diarrhea in adults inadequately controlled by somatostatin analog alone. This drug is expected to greatly improve the health and quality of life of patients with CS diarrhea.

Simple Summary Pancreatic neuroendocrine tumors (pNETs) are rare, indolent cancers whose causation is only partly understood. An increasing number of studies have uncovered molecular changes associated with pNETs, helping to identify common disease mechanisms. This knowledge has guided current pNET therapies that can effectively slow progression of the disease. However, tumors often become resistant to available therapies, necessitating a deeper understanding of mechanisms driving disease progression in order to develop new treatments. Here, we provide a comprehensive review of pNET-associated molecular alterations and existing pNET models to illustrate potential areas for advancement in research and therapy. Abstract Pancreatic neuroendocrine tumors (pNETs) are unique, slow-growing malignancies whose molecular pathogenesis is incompletely understood. With rising incidence of pNETs over the last four decades, larger and more comprehensive ‘omic’ analyses of patient tumors have led to a clearer picture of the pNET genomic landscape and transcriptional profiles for both primary and metastatic lesions. In pNET patients with advanced disease, those insights have guided the use of targeted therapies that inhibit activated mTOR and receptor tyrosine kinase (RTK) pathways or stimulate somatostatin receptor signaling. Such treatments have significantly benefited patients, but intrinsic or acquired drug resistance in the tumors remains a major problem that leaves few to no effective treatment options for advanced cases. This demands a better understanding of essential molecular and biological events underlying pNET growth, metastasis, and drug resistance. This review examines the known molecular alterations associated with pNET pathogenesis, identifying which changes may be drivers of the disease and, as such, relevant therapeutic targets. We also highlight areas that warrant further investigation at the biological level and discuss available model systems for pNET research. The paucity of pNET models has hampered research efforts over the years, although recently developed cell line, animal, patient-derived xenograft, and patient-derived organoid models have significantly expanded the available platforms for pNET investigations. Advancements in pNET research and understanding are expected to guide improved patient treatments.

Purpose: Pancreatic neuroendocrine tumors (pNETs) are uncommon malignancies noted for their propensity to metastasize and comparatively favorable prognosis. Although both the treatment options and clinical outcomes have improved in the past decades, most patients will die of metastatic disease. New systemic therapies are needed. Experimental Design: Tissues were obtained from 43 patients with well-differentiated pNETs undergoing surgery. Gene expression was compared between primary tumors versus liver and lymph node metastases using RNA-Seq. Genes that were selectively elevated at only one metastatic site were filtered out to reduce tissue-specific effects. Ingenuity pathway analysis (IPA) and the Connectivity Map (CMap) identified drugs likely to antagonize metastasis-specific targets. The biological activity of top identified agents was tested in vitro using two pNET cell lines (BON-1 and QGP-1). Results: A total of 902 genes were differentially expressed in pNET metastases compared with primary tumors, 626 of which remained in the common metastatic profile after filtering. Analysis with IPA and CMap revealed altered activity of factors involved in survival and proliferation, and identified drugs targeting those pathways, including inhibitors of mTOR, PI3K, MEK, TOP2A, protein kinase C, NF-kB, cyclin-dependent kinase, and histone deacetylase. Inhibitors of MEK and TOP2A were consistently the most active compounds. Conclusions: We employed a complementary bioinformatics approach to identify novel therapeutics for pNETs by analyzing gene expression in metastatic tumors. The potential utility of these drugs was confirmed by in vitro cytotoxicity assays, suggesting drugs targeting MEK and TOP2A may be highly efficacious against metastatic pNETs. This is a promising strategy for discovering more effective treatments for patients with pNETs.

Hip fracture and myocardial infarction cause significant morbidity and mortality. In vivo studies raising serum cholesterol levels as well as pro-inflammatory cytokines such as TNF α manifest bone loss and atherosclerotic vascular disease, suggesting that abnormalities of cholesterol transport may contribute to osteoporosis. We used the mouse osteocyte cell line (MLO-Y4) to investigate the effects of TNF α on the expression of cholesterol acceptor proteins such as apolipoprotein A-I (apo A-I) and apolipoprotein E (apo E), as well as on the cholesterol transporters ATP-binding cassette-1 (ABCA1), scavenger receptor class B type 1 (SRB1), and cluster of differentiation 36 (CD36). MLO-Y4 cells do not express apo A-I or apo E; however, they do express all three cholesterol transporters (ABCA1, SRB1, and CD36). Treatment of MLO-Y4 cells with TNF α had no effect on SRB1, CD36, and osteocalcin levels; however, TNF α reduced ABCA1 protein levels in a dose-dependent manner and cholesterol efflux to apo A-I. Interestingly, TNF α treatment increased ABCA1 promoter activity and ABCA1 mRNA levels, and increased liver X receptor α protein expression, but had no effect on retinoid X receptor α and retinoic acid receptor α levels. Pharmacological inhibition of p38 mitogen-activated protein (MAP) kinase, but not c-jun-N-terminal kinase 1 or mitogen-activated protein kinase (MEK), restored ABCA1 protein levels in TNF α-treated cells. These results suggest that pro-inflammatory cytokines regulate cholesterol metabolism in osteocytes in part by suppressing ABCA1 levels post-translationally in a p38 MAP kinase-dependent manner.

4541 Background: Anti-VEGFR2 therapy (ramucirumab/paclitaxel [RAM/TAX]) and ICI are approved as 2nd- and 3rd-line therapy (Tx), respectively, for pts with mGEA. We unexpectedly saw durable responses in 2 pts on RAM/TAX after progression on an ICI trial (KN-059; PMID 29674442). We performed a pilot to examine the clinical activity of ICI followed by RAM/TAX. Then we retrospectively compared the outcomes of pts who received this serial Tx to pts who received RAM/TAX without prior ICI. Methods: All pts with mGEA at Mayo Clinic who received RAM/TAX (2014-19) were included (N = 87). Outcomes were best objective response rate (ORR: complete [CR] or partial response) per RECIST1.1, progression-free survival (PFS), duration of response (DOR), and overall survival (OS). Chi square and multivariate (MV) logistic and Cox regression were used. Results: 15 consecutive pts with measurable mGEA received ICI immediately followed by RAM/TAX after irRECIST progression. Most pts (95%) did not respond to ICI. Yet on RAM/TAX, 100% (15/15) had tumor reduction (range -8% to -100%) with an ORR of 73% (11/15), including 3 CRs. In these pts (who received ICI followed by RAMTAX), PFS on RAMTAX was longer than on last chemotherapy before ICI (12.3 vs 3.0 m, P < .001). Outcomes on RAM/TAX in these pts were significantly better than in pts who received RAM/TAX alone (see Table). Associations were strengthened after adjusting for total lines of Tx, line of Tx of RAM/TAX, age, and ECOG PS. Exploratory analysis of paired tumor biopsies collected pre-ICI and on RAM/TAX in a small subset revealed that the frequency of intratumoral immunosuppressive FOXP3+ Tregs decreased on RAM/TAX, whereas the frequency of antitumor CD8+ T cells was preserved. Conclusions: RAM/TAX immediately preceded by ICI was associated with significantly higher OS, ORR, and DOR than RAM/TAX alone, suggesting ICI may enhance efficacy of subsequent anti-VEGFR/taxane therapy. This novel sequence of therapy will be tested prospectively in a new randomized phase 2 trial (NCT04069273). [Table: see text]

TPS461 Background: Metastatic gastroesophageal adenocarcinoma (GEA) has poor prognosis. Overall survival (OS) remains around 12 months (mo) with current therapies. Pembrolizumab is approved for advanced GEA that has progressed on at least 2 prior lines of systemic therapy. However, the majority of patients progress on this treatment, and less than 15% of patients experience objective response (OR). This study will evaluate efficacy of pembrolizumab in combination with cyclin-dependent kinase 4/6 (CDK4/6) inhibitor, abemaciclib, in patients with advanced GEA. Preclinical studies have demonstrated that CDK4/6 inhibitors can increase anti-tumor immunity and can synergize with immune checkpoint inhibitors. Based on these data, we hypothesize that abemaciclib will augment response to pembrolizumab in GEA. Methods: This is a multi-institutional, single arm, open label, phase II study of abemaciclib in combination with pembrolizumab in patients with advanced GEA who have progressed or were intolerant to at least 2 prior lines of therapy. Patients previously treated with immune checkpoint inhibitors or with microsattelite unstable tumors will be excluded. Treatments will be given on a 21 day cycle until disease progression or intolerable toxicities. Pembrolizumab, 200 mg intravenously, will be given on day 1, and abemaciclib, 150 mg, will be taken orally twice a day on days 1-21. Primary endpoint is progression free survival (PFS). Secondary endpoints include PFS rate at 6 mo, disease control rate, OS and OR rate. Correlative endpoints will examine relationship between PDL1 status, genomic signature and treatment response. Saliva samples will be collected for microbiome analysis. Archival tumor tissue and blood samples will be banked for future studies. A total of 31 evaluable subjects will be enrolled to detect an anticipated increase in the median PFS from 2 months (null hypothesis) to 4 months with 80% power at the one-sided 0.05 significance level. The trial is open to enrollment. Clinical trial information: NCT03997448.

TPS276 Background: Immune checkpoint inhibitors have revolutionized the treatment of a number of cancers. In colorectal cancers, their efficacy is limited to mismatch repair deficient or microsatellite stability-high (dMMR/MSI-High) tumors only. These constitute only 4-5% of all metastatic colorectal cancers (mCRC). Novel approaches are needed to make immunotherapy a viable option for mismatch repair proficient or microsatellite stable (pMMR/MSS) tumors. Increasing exposure of neo-antigens to the immune system could be one potential strategy to enhance the response of immunotherapy. Yttrium 90-radioembolization (Y90-RE) in combination with immunotherapy may work synergistically to enhance efficacy of each other. Additionally, radiation can potentially make the tumor microenvironment conducive to effector T-cell recruitment and function. Therefore, we hypothesize and propose the clinical trial of combining immunotherapy with Y90-RE as a feasible and safe strategy that will improve outcomes in patients with mCRC with liver-predominant metastases. Methods: This clinical trial will be conducted as a single-center, open-label, Phase I/II trial to evaluate initially the feasibility and safety of Y90-RE in combination with a fixed dose of immunotherapy (durvalumab) in subjects with liver-predominant, mCRC (Table). It will be offered in the refractory setting. The trial will be performed in 18 subjects with mCRC with liver metastasis and the safety of immunotherapy (durvalumab) with Y90-RE will be investigated in an accelerated titration design. This would allow a maximum tolerated dose with the minimum number of subjects. Correlative studies pertaining to serial circulating tumor DNA (ctDNA - liquid biopsies) testing as well as immune-panel based profiling will be performed alongside pre- and post-biopsies to study changes in the tumor microenvironment. Clinical trial information: NCT04108481. [Table: see text]

TPS791 Background: FOLFIRINOX or gemcitabine/nab-paclitaxel are both frontline chemotherapy options for patients with metastatic pancreas cancer. For most who cannot tolerate the triplet, the latter doublet is the preferred option. Through previous work by our group, pharmacologic ascorbate is known to synergize with gemcitabine; preliminary in vitro data from our group suggests a similar synergistic response with paclitaxel. Though ascorbate has been utilized in cancer therapy, few robust trials have investigated intravenous delivery of ascorbate to deliver plasma concentrations that are cytotoxic to tumor cells. Our prior studies have demonstrated ascorbate induces oxidative stress and cytotoxicity in pancreatic cancer cells; this cytotoxicity appears to be greater in tumor vs. normal cells. We hypothesize that production of hydrogen peroxide mediates the increased susceptibility of pancreatic cancer cells to ascorbate-induced metabolic oxidative stress, resulting in improved treatment outcomes, which has led to the development of the clinical trial (NCT02905578). Methods: All participants receive gemcitabine (1000 mg/m2 weekly) and nab-paclitaxel (125 mg/m2) on cycle days 1, 8, and 15 of a 28-day cycle. Participants are randomized to ± pharmacologic ascorbate (75-gram infusion 3x weekly) in addition to chemotherapy. Study therapy continues until tumor progression. The primary objective is to determine overall survival in patients when treated with combination gemcitabine, nab-Paclitaxel and high-dose ascorbic acid compared to gemcitabine and nab-paclitaxel in patients with non-resectable pancreatic cancer. Secondary objectives include determining objective response rate as well as progression free survival using RECIST 1.1 criteria employing a blinded reviewer for RECIST measurements. The study opened to accrual in 2018 with a goal of enrolling 65 participants. Oversight.Study is conducted under IND 105715 (J. Cullen, sponsor). The University of Iowa Biomedical IRB (IRB-01) serves as the IRB of record. Clinical trial information: NCT02905578.

Tolosa-Hunt syndrome (THS) is a painful condition characterized by hemicranial pain, retroorbital pain, loss of vision, oculomotor nerve paralysis, and sensory loss in distribution of ophthalmic and maxillary division of trigeminal nerve. Lymphomas rarely involve cavernous sinus and simulate Tolosa-Hunt syndrome. Here we present a first case of double-hit B cell lymphoma (DHL) relapsing and masquerading as Tolosa-Hunt syndrome. The neurological findings were explained by a lymphomatous infiltration of the right Gasserian ganglion which preceded systemic relapse. As part of this report, the diagnostic criteria for Tolosa-Hunt syndrome and double-hit lymphoma are reviewed and updated treatment recommendations are presented.

Background and Objectives: Metastatic pancreatic adenocarcinoma is the second leading cause of cancer related death in the US with limited therapeutic options. Preclinical data have shown that methylation alongside other epigenetic modifications play a role in carcinogenesis and development of chemotherapy resistance in that disease. Sarcomas are a heterogeneous group of tumors originating from mesenchyme and are associated with high rates of metastases leading to poor prognosis. Numerous epigenetic changes including hypermethylation have been identified in several sarcoma subtypes as well. Preclinical work suggested that Methylation plays a role in cellular reprogramming to a less differentiated, more invasive cell that is resistant to chemotherapy. Based on that, restoration of normal methylation patterns is a potential therapeutic target for these tumors. Experience from other disease settings showed that protracted intermittent low dosing of hypomethylating agents do have epigenetic modulating effect with less toxicity. The concept of this trial is to assess the feasibility of combining a standard of care chemotherapy with a protracted course of intermittent low dose DNMT inhibitor. Gemcitabine is a universally accepted therapy option for both pancreatic adenocarcinoma as well as Sarcomas while Decitabine is a potent DNMT inhibitor. Our primary objectives are to assess the safety and tolerability of protracted course of intermittent low dose Decitabine in combination with Gemcitabine in previously treated patients with advanced PADC and sarcomas, to identify the recommended phase 2 dosing (RP2D) and to describe the dose limiting toxicities (DLT). Methods: Patients with metastatic histologically or cytologically confirmed PADC or sarcoma (soft tissue or bone) after who meet inclusion criteria will be enrolled. Prior Gemcitabine exposure is allowed. A total of 18 patients (9 from each diagnostic group) will be enrolled. A modified 3+3 dose escalation design is employed for each diagnostic group. Two dose levels of Decitabine, 0.1 and 0.2 mg/kg subcutaneously administered on twice weekly schedule for three weeks of a 28-day cycle are being tested. Gemcitabine is given as 900 mg/m2, IV over 90 min on Days 1, 8 and 15 of a 28-day cycle. Treatment is continued until disease progression or unacceptable toxicity. DLT is defined as any drug related non-hematological grade 3 or 4 toxicities per CTCAE v 4.0. Disease assessment is performed every 8 weeks using RECIST v1.1. Patients will be monitored for tolerance and safety with routine clinical exams, laboratory studies, and periodic CT scans to assess response to therapy. The study is currently open to accrual with 5 PDAC patients and 9 Sarcoma patients already enrolled. Preliminary data has shown excellent tolerance for the regimen in the completed Sarcoma cohort and an expansion phase had been designed and is currently underway. Clinical trial identifier: NCT02959164. Citation Format: Laith Abushahin, Varum Monga, Daniel Berg, Chandrikha Chandrasekharan, Munir Tanas, Michael Henry, Mariel Mckay, Sarah Mott, Mohammed Milhem. Phase Ib study of Decitabine in combination with Gemcitabine in treatment of refractory pancreatic adenocarcinoma and advanced soft tissue or bone sarcomas [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr CT136.

420 Background: Advanced biliary cancers respond poorly to chemotherapy and have a dismal survival. Currently gemcitabine-cisplatin (GC) is the standard of care for patients with advanced disease. The efficacy of second line treatment options is not well-defined. We retrospectively evaluated outcomes of patients undergoing second line treatment for advanced biliary cancers at Mayo Clinic. Methods: After obtaining approval from the institutional board review (IRB), we identified 42 patients with advanced and metastatic biliary cancers that progressed after first line (GC) and received second line treatment from 2007-2014. All patients had adequate follow up data. JMP software was used for statistical analysis. Kaplan-Meier method and log-rank tests were used for survival analysis, and multivariate cox proportional hazards model was used to evaluate the prognostic effect of pertinent clinical variables. All tests were two sided and a P value of < 0.05 was considered significant. Results: The median age at diagnosis was 61.5 (range 26-87). The most common regimens used for second line settings were 5-FU-based (69%) followed by gemcitabine-based regimens (19%). The overall response rate (ORR) was 9.1%, while the disease control rate (DCR; stable disease and partial response) was 33%. The median overall survival (mOS) for the entire cohort from first line was 16.8 months (95% CI 12.7-21.7) and the progression-free survival (PFS) was 9.16 months (95% CI 7.3-14.7). From second line start the mOS was 10.4 months (95%; CI 7.3-23.7), and PFS was 2.8 months (95% CI 2.3-4.0). 73% of patients who received second line therapy were alive at 6 months and 50% at 12 months. 25 patients received third line treatment after progression. An univariate and multivariate analysis were performed including age, sex, stage at diagnosis, regimen used, CA19-9 and total body weight loss > 5%, but no significant prognostic factors were identified. Conclusions: Patients with biliary cancers who progress after first line treatment have poor prognosis, but may benefit from second line regimens. 5-FU based regimens were the most commonly used in the second line setting, and 73% of patients who received second line therapy were alive at 6 months.