Advanced Biliary Cancer Research Articles

Novel Palliative Chemotherapy for Cholangiocarcinoma

The term cholangiocarcinoma (CC) refers to all tumors arising from bile duct epithelium. CCs are characterized by their rarity, difficulty in diagnosis, and overall poor prognosis. This leads to a paucity of data from which to define the natural history and optimal treatment regimens. Currently, surgical resection remains the only potentially curative treatment, but many patients develop recurrence. In addition, a limited number of patients can be candidates for curative resection at diagnosis. Therefore, chemotherapy is inevitable choice for the treatment of advanced CC. Gemcitabine plus cisplatin (GP) is considered a standard option for advanced biliary cancer. A randomized phase III trial (ABC-02 trial) showed the superiority of gemcitabine plus cisplatin over gemcitabine alone. Treatment with nab-paclitaxel plus gemcitabine-cisplatin prolonged median progression-free survival and overall survival vs. those reported for historical controls treated with gemcitabine-cisplatin alone in a phase II study of 60 patients with locally advanced unresectable or metastatic biliary tract cancer. Recent data of the ABC-06 trial has provided slight evidence for the use of second-line chemotherapy after progression on cisplatin plus gemcitabine combination. Other active regimens, that could be considered in patients who include have disease progression while receiving GP and who retain an adequate performance status, includes capecitabine plus cisplatin, liposomal irinotecan plus leucovorin-modulated fluorouracil and a fluoropyrimidine alone. We herein review recent published data regarding the use of palliative chemotherapies in CC patients, with a particular focus on novel cytotoxic agents.

Hepatopancreatoduodenectomy for advanced biliary malignancies.

Hepatopancreatoduodenectomy (HPD) has been considered the only curative treatment for metastatic cholangiocarcinoma and some locally advanced gallbladder cancers (GBCs). However, HPD has not yet been included in treatment guidelines as a standard surgical procedure in consideration of its morbidity and mortality rates. The aim of this study was to evaluate the safety and effectiveness of HPD in treating biliary malignancies. The medical records of 57 patients with advanced biliary cancer undergoing HPD from January 2009 to December 2019 were retrospectively retrieved. A case-control analysis was conducted at our department. Patients with advanced GBC who underwent HPD (HPD-GBC group) were compared with a control group (None-HPD-GBC group). Baseline characteristics, preoperative treatments, tumor pathologic features, operative results, and prognosis were assessed. Thirteen patients with cholangiocarcinoma and 44 patients with GBC underwent HPD at our department. Significant postoperative complications (grade III or greater) and postoperative pancreatic fistula were observed in 24 (42.1%) and 15 (26.3%) patients, respectively. One postoperative death occurred in the present study. Overall survival (OS) was longer in patients with advanced cholangiocarcinoma than in those with GBC (median survival time [MST], 31 months vs . 11 months; P < 0.001). In the subgroup analysis of patients with advanced GBC, multivariate analysis demonstrated that T4 stage tumors ( P = 0.012), N2 tumors ( P = 0.001), and positive margin status ( P = 0.004) were independently associated with poorer OS. Patients with either one or more prognostic factors exhibited a shorter MST than patients without those prognostic factors ( P < 0.001). HPD could be performed with a relatively low mortality rate and an acceptable morbidity rate in an experienced high- volume center. For patients with advanced GBC without an N2 or T4 tumor, HPD can be a preferable treatment option.

Development and Multicentre Validation of the Modena Score to Predict Survival in Advanced Biliary Cancers Undergoing Second-Line Chemotherapy.

BackgroundThe role of second-line chemotherapy in advanced biliary cancers (ABCs) has only recently been established in phase III randomized trial and the optimal selection of patients most likely to benefit from it remains challenging.MethodsA cohort of 98 ABC treated second-line chemotherapy was used as a developmental dataset to identify covariates independently associated with overall survival (OS). Kaplan–Meier analysis was used to investigate the association between variables and OS and those retaining statistically significance were combined in a multiplexed score.ResultsThe following pretreatment variables were independently associated with OS: ECOG PS > 0, peritoneal disease, LDH > 430 UI/L, albumin <3.5 gr/dL, gamma-GT >100 UI/L, sodium <140 mEq/L, absolute lymphocyte count <1000/mmc, and PFS to first-line <6 months. Based on these results, a scoring system was developed that identified three subgroups with statistically different OS: low-risk (mOS 18 months), intermediate-risk (mOS 9.4 months) and high-risk (mOS 2.9 months) (p < 0.001). The prognostic model was both internally and externally validated in a multicentre cohort of 120 ABCs.ConclusionThe Modena score is a multiplexed scoring system capable of accurately risk-stratified ABCs treated with second-line chemotherapy. Based on its reproducibility, usability and generalizability, it has the potential for assisting therapeutic decision-making in the clinic and risk-stratification in future trials.

Pembrolizumab (PEM) plus granulocyte macrophage colony stimulating factor (GM-CSF) in advanced biliary cancers (ABC): Final outcomes of a phase 2 trial.

444 Background: Immune checkpoint inhibitors (ICI) have limited activity as monotherapy in unselected patients with ABC; the objective response rate (ORR) of PEM was 5.8% in the multicenter phase 2 KEYNOTE-158 trial. GM-CSF modulates immune cells including monocytes and the innate immune response and has demonstrated safety and prolonged survival (OS) in combination with ipilimumab in melanoma. This phase 2 trial was designed to evaluate the efficacy and safety of PEM in combination with GM-CSF in ABC. Methods: Single-center, phase 2 trial with Simon’s 2-stage design and expansion cohort (EC) (NCT02703714). Key eligibility: ABC with progression/intolerance on ≥ 1 standard therapy, no prior ICI, bilirubin ≤1.5xULN. Treatment: PEM 200 mg IV Q21 days plus 2 cycles of GM-CSF 250 µg SC D1-14 Q21 days in cycles 2 and 3 (Stage 1 and EC) or in cycles 1 and 2 (Stage 2). Primary endpoint was objective response rate (ORR) by RECIST 1.1, H0 5% vs. H1 20%. Key secondary endpoints were safety, progression-free survival (PFS), OS, PD-L1 expression. Exploratory endpoints included relationship between efficacy outcomes and anatomic subsite, risk factors, and tumor genotype. Results: Overall, 42 patients enrolled between 5/2016-12/2019: n = 9 in Stage 1, n = 18 in Stage 2, and n = 15 in EC. Overall: median age 61; female 67%; intrahepatic (ICC) 67%, extrahepatic (ECC) 26%, gallbladder (GBC) 7%; stage IV 90%; hepatitis B/C virus positive (HBV/HCV+) 24%; microsatellite instability (MSI-H)/stable (MSS)/unknown n = 1/35/6. Immune-related (ir)AE occurred in 69%, grade 3/4 treatment-related (tr)AE in 10%, all-cause serious (S)AE in 36%, and trSAE in 7%. ORR was 12% (95% CI: 4, 26), with median PFS of 63 days (95% CI: 55, 125), PFS at 6 months in 27% (95% CI: 14, 43), and median OS 3of 93 days (95% CI: 243, 573). There was no significant difference in ORR, PFS, or OS by anatomic subsite or tumor PD-L1 expression; HBV/HCV+ showed trends toward higher ORR (30% vs 6%, p = 0.08) and longer median PFS (276 vs 63 days, p = 0.06) and OS (1033 vs 323 days, p = 0.052). Conclusions: The combination of PEM plus GM-CSF was safe and well-tolerated with higher ORR than expected for PEM monotherapy in a predominantly MSS ABC population but did not meet target ORR threshold for efficacy. ORR and median PFS and OS were highest in patients with underlying HBV or HCV infection. Immune profiling of on-treatment biopsies and peripheral blood are ongoing to ascertain influence of both PEM and GM-CSF on circulating and tumor immune microenvironment. Clinical trial information: NCT02703714.

A phase Ib study of guadecitabine and durvalumab in patients with advanced hepatocellular carcinoma, pancreatic adenocarcinoma, and biliary cancers.

574 Background: Pancreatic (PC) and biliary cancers (BC) are cold tumors with limited activity of single agent immune checkpoint inhibitors. DNA methyltransferase inhibitors (DNMTi) have immunomodulatory effects manifested by upregulation of interferon pathways and expression of endogenous retroviral signatures. We performed a phase Ib study of the DNMTi guadecitabine (G) and durvalumab (D) in patients (pts) with hepatocellular carcinoma, PC and BC. We report initial results from the PC and BC cohorts. Methods: This is a phase Ib study to establish the maximum tolerated dose (MTD) of the combination (dose escalation; 3+3 design) and evaluate the objective response rate (ORR) in expansion cohorts of PC and BC. G was given at escalating doses of 30 mg/m2 and 45 mg/m2 subQ for 5 days q 28 days. D was given at 1500 mg IV on day 8 of each cycle. Expansion was started at the MTD. Eligibility criteria included ECOG 0-1, ANC ≥ 1,500, platelets &gt; 100,000, albumin ≥ 2.5 g/dL, total bilirubin ≤ 2.5 x upper limit of normal, failure of ≥ 1 prior line of therapy for advanced disease. Prior anti PD-1/PDL-1 was not allowed. Tumor biopsies were performed during screening and on cycle 3 day 1. Results: A total of 11 pts were treated in dose escalation; 3 at dose level 1, and 8 (6 evaluable for DLT) at dose level 2. Given lack of dose-limiting toxicities, MTD was the highest planned dose of G at 45 mg/m2. 24 pts with PC and 23 pts with BC were treated in dose escalation and expansion. For the PC cohort: median age was 66 (43, 93), 29% female, 67% ECOG 1, and median number of prior therapies 2 (1,3). For the BC cohort: median age was 61 (41, 85), 52% female, 78% ECOG 1, and median number of prior therapies 1 (1,3). All grade treatment related AEs in ≥10% of pts were neutropenia (55%), leukopenia (50%), anemia (33%), fatigue (33%), thrombocytopenia (17%), nausea (15%), and anorexia (10%). Grade 3/4 AEs in ≥10% of pts were neutropenia (40%), leukopenia (35%), and anemia (13%). There was 1(5%) PR in PC cohort lasting &gt; 24 mo and ongoing and 1(5%) in BC cohort lasting 12 mo; both were in MSS pts. SD was noted in 7/24 (29%) PC and 5/23 (22%) BC pts, 8 of which lasted ≥4 mo. Median PFS for PC and BC was 2.1 mo [1.9, 3.8] and 1.9 mo [1.4, 2] respectively. Median OS for PC and BC was 4.4 mo [3.4, NR] and 8.6 mo [6.4, NR]. Six and 12 mo OS rates are 38% [21, 66] and 27% [13, 56] for PC; 69% [52, 91] and 35% [19, 63] for BC. 4% of PC pts and 42% of BC pts received another therapy after progression. Conclusions: The combination of G and D has a manageable safety profile in pts with advanced PC and BC; grade 3/4 AEs were limited to myelosuppression. The combination had limited clinical activity based on ORR and PFS in this unselected, pretreated population; however, a subset of pts appeared to derive prolonged clinical benefit, and OS rates were comparable to standard second line chemotherapy, despite a minority of pts receiving subsequent treatment. Biomarker analyses are ongoing. Clinical trial information: NCT03257761.

T-Cell Subsets as Potential Biomarkers for Hepatobiliary Cancers and Selection of Immunotherapy Regimens as a Treatment Strategy.

Patients with advanced hepatocellular or biliary cancers have a dismal prognosis with limited efficacy from standard systemic therapies. The benefit of precision medicine has so far been limited to a subset of biliary cancers, including FGFR rearrangements; hotspot mutations in IDH1/2, BRAF, and BRCA1/2; and other rare alterations. In contrast, hepatocellular carcinoma, an inflammation-driven cancer with an immune-infiltrated microenvironment, provides a promising opportunity for immunotherapy, compared with the highly desmoplastic immune desert or excluded stromal microenvironment in biliary cancers. The immune contexture in hepatobiliary cancers is mostly immunosuppressive, protumorigenic, and exhausted, which together with low tumor mutation burden and decreased neoantigens provides challenges for immunotherapy. A better understanding of the spatiotemporal profile of T cells within the tumor microenvironment and the dynamic interplay of immune modulators in the context of standard or experimental therapies is crucial to define additional markers of response and design evidence-based combinatorial regimens. This review considers recent literature in this area and highlights promising leads and emerging trends.

Third-line chemotherapy in advanced biliary cancers (ABC): pattern of care, treatment outcome and prognostic factors from a multicenter study

ABSTRACT Objectives Here, we aim at describing the pattern of care, survival outcome and prognostic factors of ABC patients (pts) receiving third-line chemotherapy. Methods Institutional registries across three academic medical centers were retrospectively reviewed. Kaplan–Meier estimators were used to calculate survival, the log-rank test to make comparisons, and the Cox proportional hazard models to assess the progostic impact of variables. Results Among 101 pts included in the analysis. 68 (67.3%), 19 (18.8%) and 14 (13.8%) had intrahepatic and extrahepatic cholangiocarcinoma and gallbladder cancer, respectively. Atotal of 63 (62.3%) pts received monochemotherapy, while 38 (37.6%) were treated with adoublet. The median OS and PFS were 5 and 3 months, respectively. Disease control rate was achieved in 23 (22.7%) pts, with 2 (2%) partial responses. Grade 3–4 treatment-related adverse events were reported in 22 (21.7%) pts. At multivariate analysis, ECOG PS (p < 0.001), tumor burden (p = 0.01) and lymphocyte-to-monocyte ratio (p =0.02) were independent predictors of survival. Conclusions Third-line chemotherapy displayed limited activity in this real-world cohort, although prognostic factors have been identified that may assist in treatment decision. The results of this multicenter experience, highlight the need for more effective therapies and provide a benchmark for future trials in this setting.

FOLFIRINOX Not Better Than Gemcitabine-Cisplatin in Biliary Cancer

Standard chemotherapy agents for advanced biliary cancer are gemcitabine and cisplatin. Recent data suggest a modest benefit for use of second-line

Abstract PO-018: Inflaming advanced solid tumors including pancreatic cancer using LOAd703, a TMZ-CD40L/4-1BBL-armed oncolytic virus

Abstract Pancreatic ductal adenocarcinoma (PDAC) is resistant to PD1/PDL1 blocking antibodies. The purpose of this study was to evaluate if immunotherapy with LOAd703, an oncolytic adenovirus armed with trimerized CD40L and 4-1BBL, can sensitize PDAC to mAbs targeting PD1/PDL1. The high content of myeloid-derived suppressor cells (MDCSs) in the tumor microenvironment may in part explain the limited anti-tumor T cell response in PDAC. We have previously shown that gemcitabine can reduce MDSCs in patients with PDAC, with the T cell proliferative capacity remaining intact. Further, LOAd703 has been demonstrated to efficiently and robustly kill PDAC cells and stimulate the maturation of dendritic cells (DCs), which, in turn, induces T cell activation. Patients with advanced PDAC, colorectal, biliary, and ovarian cancer (NCT03225989) were treated with intratumoral injections of LOAd703 combined with appropriate chemotherapy such as gemcitabine ± nab-paclitaxel for PDAC patients, or combined with gemcitabine if there was no standard of care. Blood sampling was performed for immune cell profiling and anti-adenovirus antibodies (flow cytometry, ELISA). Tumor biopsies were also analyzed for mRNA expression (NanoString; PanCancer Immune Profiling Panel). The study was approved by the ethical review board and the Swedish Medical Products Agency. The dose of LOAd703 was escalated (5 × 10e10 VP, 1 × 10e11 VP, 5 × 10e11VP) in separate cohorts of new patients and administered every other week. To date, blood samples from 23 patients have been analyzed by flow cytometry to profile immune cells. The mean percentages of monocytic- and granulocytic MDSCs, Tregs and M2-like myeloid cells were significantly decreased after treatment initiation. The effector memory (EM) and central memory (CM) CD8+ T cells were significantly increased, while naïve and CM cells were increased among CD4 T cells. Both CD4 and CD8 T cells expressing ICOS were present post-treatment but only CD8 T cells showed significant elevation of PD1. The NanoString data were analyzed using published mRNA immune signatures (bioinformatics). LOAd703 in combination with chemotherapy inflamed tumor lesions as shown by increased markers of the T cell inflamed signature (16 genes), T effector cell signature (19 genes), expanded immune signature (25 genes) and IFNg-related gene signature (12 genes) (week 1 versus week 13). Anti-adenovirus antibody titers increased in all patients after treatment initiation. The antibody levels did not correlate with the dose of virus, radiological response to treatment, nor overall survival. The results presented herein show that LOAd703 combined with chemotherapy enhances immune reactivity in patients with immune cold tumors as demonstrated by increases in EM and CM T cells in the peripheral blood, while suppressive immune cells were decreased. Further, the tumor milieu was inflamed post treatment as shown by mRNA profiling. Hence, LOAd703 may sensitize immune cold tumors to mAbs targeting PD1/PDL1. Citation Format: Jessica Wenthe, Emma Eriksson, Linda Sandin, Tanja Lövgren, Justyna Leja Jarblad, Hanna Dahlstrand, Ulla Olsson-Strömberg, Aglaia Schiza, Anders Sundin, Sandra Irenaeus, Eric Rowinsky, Gustav Ullenhag, Angelica Loskog. Inflaming advanced solid tumors including pancreatic cancer using LOAd703, a TMZ-CD40L/4-1BBL-armed oncolytic virus [abstract]. In: Proceedings of the AACR Virtual Special Conference on Pancreatic Cancer; 2021 Sep 29-30. Philadelphia (PA): AACR; Cancer Res 2021;81(22 Suppl):Abstract nr PO-018.

Association of cell-free DNA dominant clone allele frequency with poor outcomes in advanced biliary cancers treated with platinum-based chemotherapy.

4079 Background: Cell-free circulating tumor DNA (ctDNA) holds significant promise and is being used for clinical decision making in multiple tumors. This study aimed to evaluate the prognostic value of pre-treatment ctDNA in metastatic biliary tract cancers (BTC) treated with platinum based first-line chemotherapy treatment. Methods: We performed a retrospective analysis of 67 patients who underwent ctDNA testing before platinum-based chemotherapy for first-line treatment for metastatic BTC. For analysis we considered the detected gene with highest variant allele frequency (VAF). Results of ctDNA analysis were correlated with patients’ demographics, progression-free survival (PFS) and overall survival (OS). Results: The median age of patients was 67 y/o (27-90). 54 (80.6%) of 67 patients evaluated had intrahepatic cholangiocarcinoma; seven had extrahepatic cholangiocarcinoma and six gallbladder cancer. 46 (68.6%) of the patients were treated with cisplatin plus gemcitabine, 14 (21%) patients received gemcitabine and other platinum (carboplatin or oxaliplatin) combinations while 7 (10.4%) patients were treated on a clinical trial with gemcitabine and cisplatin plus additional targeted agents (CX4945 or PEGPH20). TP53, KRAS, APC, FGFR2 and IDH1 were the genes with highest frequency as dominant clone. The median dominant clone allele frequency (DCAF) was 3% (0-97%). DCAF &gt;3% was associated with statistically significant worse PFS (median PFS: 4.05 vs. 7.70 months, p=0.046) and OS (median OS: 10.8 vs. 18.8 months, p=0.056). Each 1% increase in DCAF is associated with a hazard ratio of 26.21 in OS when adjusting for subtypes, age, treatment type, and CA19-9 [Table]. Conclusions: Patients with metastatic BTC with DCAF &gt; 3% at diagnosis have worse PFS and OS compared to patients with low ctDNA when treated with upfront platinum-based chemotherapy.[Table: see text]

Stent placement combined with intraluminal radiofrequency ablation and hepatic arterial infusion chemotherapy for advanced biliary tract cancers with biliary obstruction: a multicentre, retrospective, controlled study

ObjectiveTo evaluate the efficacy and safety of stent placement combined with intraluminal radiofrequency ablation (intra-RFA) and hepatic arterial infusion chemotherapy (HAIC) for patients with advanced biliary tract cancers (Ad-BTCs) and biliary obstruction (BO).MethodsWe retrospectively reviewed data for patients with Ad-BTCs and BO who underwent stent placement with or without intra-RFA and HAIC in three centres between November 2013 and November 2018. The stent patency time (SPT), overall survival (OS), and adverse events (AEs) were analysed.ResultsOf the 135 enrolled patients, 64 underwent stent placement combined with intra-RFA and HAIC, while 71 underwent only stent placement. The median SPT was significantly longer in the combination group (8.2 months, 95% confidence interval [CI]: 7.1–9.3) than in the control group (4.3 months, 95% CI: 3.6–5.0; p < 0.001). A similar result was observed for OS (combination: 13.2 months, 95% CI: 11.1–16.5; control: 8.5 months, 95% CI: 7.6–9.6; p < 0.001). The incidence of AEs related to biliary tract operation was not significantly different between the two groups (p > 0.05). The most common AE and serious AE related to HAIC were alanine aminotransferase elevation (24/64; 37.5%) and thrombocytopenia (8/64; 12.5%), respectively. All AEs were tolerable, and there was no death from AEs.ConclusionsStent placement combined with intra-RFA and HAIC may be a safe, potential treatment strategy for patients with Ad-BTCs and BO.Key Points• Advanced biliary cancers (Ad-BTCs) with biliary obstruction (BO) can rapidly result in liver failure and cachexia with an extremely poor prognosis.• Stent placement combined with intraluminal radiofrequency ablation and hepatic arterial infusion chemotherapy may be safe and effective for patients with Ad-BTCs and BO.• The long-term efficacy and safety of the combined treatment is promising.

Hepatopancreatoduodenectomy for Biliary Cancer - Are the Outcomes Acceptable?-

Background: Hepatopancreatoduodenectomy (HPD) is usually indicated for advanced biliary cancer. Operative resection is the only way to cure for the advanced biliary cancer patients. However HPD is infrequently performed widely because of high morbidity and mortality. The aim of this retrospective study was to clarify the impact of resected liver volume on outcomes of HPD.

Chemoradiotherapy for patients with locally advanced or unresectable extra-hepatic biliary cancer.

Although surgical resection is the preferred curative-intent treatment option for patients with non-metastatic, extra-hepatic biliary cancer (EBC), radiotherapy (RT) or chemoradiotherapy (CRT) may be utilized in select cases when surgical resection is not feasible. The purpose of this study is to report the efficacy and adverse events (AEs) associated with CRT for patients with locally advanced and unresectable EBC. This was a retrospective cohort study of patients with EBC, including extra-hepatic cholangiocarcinoma or gallbladder cancer, deemed inoperable who received RT between 1998 and 2018. The median RT dose was 50.4 Gy in 28 fractions and 94% received concurrent 5-fluorouracil. The Kaplan-Meier method was used to estimate overall survival (OS) and progression-free survival (PFS) from the start of RT. The cumulative incidence of local progression (LP), locoregional progression (LRP), and distant metastasis (DM) were reported with death as a competing risk. Cox proportional hazards regression models were used to assess for correlation between patient and treatment characteristics and outcomes. Forty-eight patients were included for analysis. The median OS was 12.0 months [95% confidence interval (CI): 2.3-73.2 months]. The 2-, 3-, and 5-year OS were 33% (95% CI: 22-50%), 20% (95% CI: 11-36%), and 7% (95% CI: 2-20%), respectively. The 2-year PFS, LP, LRP, and DM were 21% (95% CI: 12-36%), 27% (95% CI: 17-44%), 31% (95% CI: 20-48%), and 33% (95% CI: 22-50%), respectively. On univariate analysis, biologically effective dose (BED) >59.5 Gy10 was associated with improved OS [hazard ratio (HR): 0.40, 95% CI: 0.18-0.92, P=0.03] and PFS (HR: 0.37, 95% CI: 0.16-0.84, P=0.02) and primary tumor size (per 1 cm increase) was associated with worsened PFS (HR: 1.29, 95% CI: 1.02-1.63, P=0.04). BED >59.5 Gy10 remained associated with PFS on multivariate analysis (HR: 0.34, 95% CI: 0.15-0.78, P=0.01). Treatment-related grade 3+ acute and late gastrointestinal AEs occurred in 13% and 17% of patients, respectively. RT is associated with 3- and 5-year survival in a subset of patients with unresectable EBC. Further exploration of the role of RT as part of a multi-modality curative treatment strategy is warranted.

57P Third-line chemotherapy in advanced biliary cancers (ABC): Pattern of care, treatment outcome and prognostic factors from a multicenter study

57P Third-line chemotherapy in advanced biliary cancers (ABC): Pattern of care, treatment outcome and prognostic factors from a multicenter study

Abstract 5512: Identification of circulating myeloid cells induced in advanced biliary cancer patients responding to anti-PD1 through combined single cell RNA sequencing and protein expression analysis

Abstract Background: Patients with advanced biliary cancer (ABC) have low rates of response to immune checkpoint inhibition (CPI) monotherapy. We conducted a phase II clinical trial studying combination immunotherapy with GM-CSF and the anti-PD-1 antibody, pembrolizumab (NCT02703714), with preliminary objective response rate of 19%, higher than the reported response rate of 5.8% for pembrolizumab monotherapy in ABC. Mechanisms of response to CPI in ABC are unknown, and to our knowledge, there have not been studies of the immune response in this patient population at the single cell level. Methods: Cryopreserved serial peripheral blood mononuclear cells (PBMC) samples from n=27 ABC patients treated with pembrolizumab plus GM-CSF were assessed with single cell RNA sequencing combined with CITE-Seq, the staining of cells with &amp;gt;90 oligo-tagged antibodies. This allows for the simultaneous identification of protein and RNA expression on an individual cell basis. We used high-throughput multiplexing in which PBMC from different patients could be deconvolved from other mixed samples using individual specific SNPs (“demuxlet”). &amp;gt;100 PBMC samples, including pre-treatment and 1 week, 3 weeks, and 6 weeks post-treatment, were studied. Nine of 27 patients were characterized as responders, while 18 were non-responders. We also performed CITE-Seq on PBMC from age/gender-matched healthy controls (n=9). Results: Unbiased clustering revealed all major immune populations were present in PBMC from both ABC and controls, though the immune compositions differed, most strikingly within the myeloid compartment. A distinct population of CXCL5-expressing “cancer-associated myeloid cells”, distinct from classical and non-classical monocytes and dendritic cells, was found only within cancer patients. We also analyzed the effects of treatment on immune sub-populations within responders and non-responders and found that following anti-PD-1 monotherapy, there was an increased frequency and absolute number of non-classical monocytes in responders. Conversely, the addition of GM-CSF to anti-PD-1 therapy decreased the frequency of circulating non-classical monocytes, though there was a robust induction of pro-inflammatory genes following treatment with GM-CSF in responders. Regardless of responder status, GM-CSF also dramatically induced monocyte-derived dendritic cells within 1 week of administration. Conclusions: The compositions of the myeloid compartment differed between ABC patients and healthy individuals, with a circulating cancer-associated myeloid population identified in ABC patients. Circulating non-classical monocytes increased following anti-PD-1 monotherapy in all patients, but declined after combination with GM-CSF in responders, suggesting that anti-PD-1-induced myeloid populations may be associated with response to anti-PD1. Pre-existing and induced myeloid cell states may represent a mechanism of response to anti-PD-1 and GM-CSF. Citation Format: Bridget P. Keenan, Elizabeth E. McCarthy, Arielle Ilano, David S. Lee, Yang Sun, Brenna Sheldon, Alexander Cheung, Chun Jimmie Ye, Robin Kate Kelley, Lawrence Fong. Identification of circulating myeloid cells induced in advanced biliary cancer patients responding to anti-PD1 through combined single cell RNA sequencing and protein expression analysis [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 5512.

A phase Ib study of sEphB4-HSA combined with first-line chemotherapy in patients (pts) with advanced pancreatic (PC) and biliary cancers (BC).

4640 Background: EphB4, a receptor kinase expressed in most epithelial tumors, binds EphrinB2 to affect cancer cell growth, apoptosis and angiogenesis. EphB4 overexpression is associated with advanced stage and shorter survival in multiple cancers. sEphB4-HSA, the albumin-bound extracellular fragment of EphB4, is a first-in-class inhibitor which blocks EphB4-EphrinB2 bidirectional signaling and results in downstream suppression of KRAS, PI3K, and promotes recruitment of CD3 and CD8 T cells into the tumor. The RP2D of sEphB4-HSA is 10 mg/Kg IV q week. Here, we report on sEphB4-HSA in combination with standard first-line chemotherapy. Methods: Pts with advanced PC or BC and no prior therapy for metastatic disease were eligible and enrolled into separate cohorts. Pts with PC received gemcitabine 1,000 mg/m2 + nab-paclitaxel 125 mg/m2 on Days 1, 8, 15 of a 28-day cycle. Pts with BC received gemcitabine 1,000 mg/m2 + cisplatin 25 mg/m2 on Days 1, 8 of a 21-day cycle. sEphB4-HSA 10 mg/kg IV was given weekly starting in Cycle 2. Response was assessed every 2 cycles. Primary endpoint was safety and tolerability; secondary endpoints were objective response rate (ORR) by RECIST 1.1, PFS, OS. Expression of EphrinB2 and EphB4 in tumor was examined by IHC and classified as 1+ (weak staining); 2+ (moderate staining); 3+ (strong, uniform staining). Results: A total of 44 pts with advanced PC (n = 21) and BC (n = 23; 70% gallbladder cancer) were enrolled. Median age 66 yrs; ECOG 1 (70%), 52% male. Median number of cycles received were 5 (PC) and 7 (BC). Median PFS was 5.6 mo in PC and 5.8 mo in BC (95% CI: 3.1-8.1 [PC]; 2.7-7.0 [BC]). Median OS was 7.9 mo in PC and 9.1 mo in BC (95% CI: 6.5-15.0 [PC]; 5.4-15.0 [BC]). In response evaluable pts (20 PC, 22 BC), ORR was 40% in PC (95% CI: 21%, 63%) and 23% in BC (95% CI: 9%, 45%). Stable disease was noted in 48% of PC and 61% of BC pts. The most common grade 3 or 4 treatment-related AEs in ≥10% of pts in both cohorts combined were hypertension (n = 16; 36%), neutropenia (n = 15; 34%), anemia (n = 14; 32%), thrombocytopenia (n = 7, 16%), fatigue (n = 7, 16%). In the PC cohort, there was an association between EphB4 expression and objective response (p = 0.009). Conclusions: sEphB4-HSA has a manageable safety profile in combination with chemotherapy in pts with PC and BC. Clinical activity is manifested by a high disease control rate in both cohorts and a promising RR in PC. Additional biomarker analyses will be presented. Future studies combining chemoimmunotherapy with sEphB4-HSA in pancreatic cancer are planned. Clinical trial information: NCT02495896 .

Impact of immunotherapy use in patients with stage IV biliary carcinoma.

e16597 Background: Most patients with cholangiocarcinoma have non resectable disease at the time of diagnosis and usually die within 6-12 months. The 5-year survival rate is very low (about 5%), and since most patients present with advanced disease at time of diagnosis, treatment includes chemoradiation and biliary stenting. Recently, trials with immunotherapy (IO) for treatment of advanced cancer have shown promising results as alternative therapeutic options. Despite indications in other solid tumors, the role of IO is unknown for biliary cancer. Methods: Using National Cancer Database (NCDB), cases of Stage IV biliary cancers (including gallbladder and cholangiocarcinoma) diagnosed in the period of 2014-2016 with at least 30-day follow up were analyzed. The following clinical demographics were included: age (younger than 70 vs. older than 70), sex (male vs. female), race (whites vs. others), insurance (uninsured vs. insured), liver metastasis (Yes vs. No). We also analyzed data regarding cancer treatment, including radiation (Yes vs. No), chemotherapy (Yes vs. No), and IO (Yes vs. No). Survival analysis was performed using Kaplan-Meier curves and Log-rank tests. A p-value &lt; 0.05 was considered significant. Results: Among 6,344 eligible cases, 57 patients were treated with IO. No significant association between use of IO and clinical demographics was observed except for use of chemotherapy (p = 0.001) and primary location (gallbladder vs. others, p = 0.042). Chemotherapy was administered in 52 (91%) and 4112 (65%) of cases in IO and non-IO groups, respectively. Use of IO was associated with improved overall survival in both univariate and multivariate analyses (p = 0.0005and 0.0156, respectively). Median overall survival (in months) was 14.0 in the IO group vs 7.0 in the non-IO group. Landmark analysis in the IO group showed 12 and 24-month survival of 56.1% and 19.3% respectively, as compared with 27.8% and 7.6% in the non-IO group. Conclusions: This retrospective data analysis using a large cancer database suggests that use of IO could improve survival in patients with advanced biliary cancer. More studies will be needed in the future to validate these results.

Mutational landscape and tumor mutation burden (TMB) feature of biliary cancer.

e16670 Background: Biliary cancer are relatively rare, highly aggressive and have poor prognoses. Most biliary cancers are diagnosed in the advanced and metastatic stages. Chemotherapy is the main treatment of advanced biliary cancer. We focus on gene mutation and tumor mutation burden (TMB) of biliary cancer. Methods: We retrospectively reviewed one hundred and fifty-six cases of biliary cancer. One hundred and fifty-six tumor tissues and 35 plasma samples were subjected to next-generation sequencing (NGS), which enables simultaneously assess snv, indel, rearrangements and cnv variations at least 59 genes (range 59-1021 genes). Results: Fifty-eight patients were intrahepatic cholangiocarcinoma (IHCC), 50 were extrahepatic cholangiocarcinoma (EHCC) and 48 were gall bladder cancer (GBC). From tissue samples, the commonly mutated genes were different in three groups. TP53 was the most frequently mutated gene among the three groups (IHCC 43%, EHCC 58%, GBC 79%). KRAS (33%), TERT (16%), LRP1B (16%), IDH1/2 (10%) were usual in IHCC. KRAS (28%), SMAD4 (20%), STK11 (18%), ARID1A (12%) were usual in EHCC. And ERBB2 (19%), LRP1B (17%), TERT (15%), MLL3 (15%) were usual in GBC. TP53, LRP1B and MLL3 had a higher frequency in GBC than cholangiocarcinoma (p &lt; 0.05), and KRAS was more common in cholangiocarcinoma than GBC (p &lt; 0.05). 72.4% IHCC, 76.0% EHCC and 60.4% GBC had gene mutation associated with target therapies, which involved in multiple signal pathway, such as IDH1/2, FGFR, ERBB1/2/3, MET, PIK3CA, PTEN, BRCA, etc. Thirty-five patients had paired tissue and plasma samples, 21 stage Ⅲ/Ⅳ, 11 stage Ⅱ and 3 unknown. The concordance between tissue and plasma was 53% in all patients and was higher in stage Ⅲ/Ⅳ than stage Ⅱ (p &lt; 0.05). One hundred and thirty-three tissue samples assessed TMB, the mean TMB was highest in the GBC group, followed by EHCC and IHCC (7.1 vs 5.5 vs 3.9 muts/Mb, p &lt; 0.05). The proportion of TMB-H (defined 9.0 muts/Mb as cutoff value) was higher in GBC than IHCC and EHCC. Conclusions: IHCC, EHCC, and GBC have distinctive mutational landscapes and TMB features. It maybe guide different target therapy and immunotherapy strategies in the clinic. ctDNA has promising potential in biliary cancer.

Efficacy and safety of pembrolizumab for the treatment of advanced biliary cancer: Results from the KEYNOTE-158 and KEYNOTE-028 studies.

We present data from patients with advanced biliary tract cancer (BTC) receiving pembrolizumab in the KEYNOTE-158 (NCT02628067; phase 2) and KEYNOTE-028 (NCT02054806; phase 1b) studies. Eligible patients aged ≥18 years from both studies had histologically/cytologically confirmed incurable BTC that progressed after standard treatment regimen(s), measurable disease per Response Evaluation Criteria in Solid Tumors (RECIST) version 1.1, Eastern Cooperative Oncology Group performance status 0/1, and no prior immunotherapy. Programmed death ligand 1 (PD-L1)-positive tumors were required for eligibility in KEYNOTE-028 only. Patients received pembrolizumab 200 mg every three weeks (KEYNOTE-158) or 10 mg/kg every two weeks (KEYNOTE-028) for ≤2 years. Primary efficacy endpoint was objective response rate (ORR) by RECIST v1.1. Response assessed by independent central review is reported. KEYNOTE-158 enrolled 104 patients and KEYNOTE-028 enrolled 24 patients. Median (range) follow-up was 7.5 months (0.6-34.3) in KEYNOTE-158 and 5.7 months (0.6-55.4) in KEYNOTE-028. In KEYNOTE-158, ORR was 5.8% (6/104; 95% CI, 2.1%-12.1%); median duration of response (DOR) was not reached (NR) (range, 6.2-26.6+ months). Median (95% CI) OS and PFS were 7.4 (5.5-9.6) and 2.0 (1.9-2.1) months. Among PD-L1-expressers (n = 61) and PD-L1-nonexpressers (n = 34), respectively, ORR was 6.6% (4/61) and 2.9% (1/34). In KEYNOTE-028, ORR was 13.0% (3/23; 95% CI, 2.8%-33.6%); median DOR was NR (range, 21.5-53.2+ months). Median (95% CI) OS and PFS were 5.7 (3.1-9.8) and 1.8 (1.4-3.1) months. Grade 3 to 5 treatment-related adverse events occurred in 13.5% of patients in KEYNOTE-158 (no grade 4; grade 5 renal failure, n = 1) and 16.7% in KEYNOTE-028 (no grade 4/5). In summary, pembrolizumab provides durable antitumor activity in 6% to 13% of patients with advanced BTC, regardless of PD-L1 expression, and has manageable toxicity.

Randomised phase II trial (SWOG S1310) of single agent MEK inhibitor trametinib Versus 5-fluorouracil or capecitabine in refractory advanced biliary cancer

BackgroundThe rationale for the evaluation of trametinib in advanced biliary cancer (BC) is based on the presence of mitogen-activated protein kinase alterations and on earlier promising results with MEK inhibitors in BC. MethodsPatients with histologically proven BC who progressed on gemcitabine/platinum were randomised to trametinib daily (arm 1) versus fluoropyrimidine therapy (infusional 5-fluorouracil or oral capecitabine, arm 2). The primary end-point was overall survival (OS). Secondary end-points included progression free survival (PFS) and response rate. A planned interim futility analysis of objective response was performed on the first 14 patients registered to the trametinib arm. ResultsThe study was stopped early based on the lack of measurable response in the trametinib arm. A total of 44 eligible patients were randomised (24 patients in arm 1 and 20 patients in arm 2). Median age was 62 years and the primary sites of tumour were cholangiocarcinoma (68%) and gallbladder (32%). The overall response rate was 8% (95% CI 0%–19%) in arm 1 versus 10% (95% CI 0%–23%) in arm 2 (p > .99) Median OS was 4.3 months for arm 1 and 6.6 months for arm 2. The median PFS was 1.4 months for arm 1 and 3.3 months for arm 2. ConclusionsThis is the first prospective randomised study of a targeted agent versus chemotherapy for the second-line treatment of BC. In this unselected population, the interim analysis result of unlikely benefit with trametinib resulted in early closure.