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Our previous phase II study demonstrated that nivolumab provides modest but durable clinical efficacy in patients with refractory biliary tract cancer, suggesting the significant clinical benefit of nivolumab in selected patients and the necessity of predictive biomarkers. We evaluated clinicopathological characteristics and tumour microenvironment of the patients who were enrolled the trial to identify potential biomarkers.Baseline clinicopathological characteristics and pretreatment tumour samples were collected. The obtained tumour samples were assessed for whole exome sequencing, RNA sequencing and immunohistochemistry. Their correlations with clinical outcome were analysed.Pretreatment tumour evaluation revealed PD-L1 expression on tumour, CD8 T cell infiltration and high ratio of CD8 T cell/regulatory T cell in tumour microenvironment were significantly associated with prolonged progression-free survival (PFS), while PD-1 expression on lymphocytes and CD68 macrophages infiltration in tumour microenvironment had no predictive role. Asian patients (N = 3) had improved PFS and disease control rate compared with non-Asian (N = 54). A six-gene predictive model was constructed by evaluation of total 23,550 candidate genes from RNA sequencing of baseline tumour samples using LASSO-Cox regression analysis, and high score of the six-gene prediction model was associated with prolonged PFS.This study suggests that PD-L1 expression on tumour, CD8 T cell infiltration and high ratio of CD8/regulatory T cells and six-gene expression profile in tumour microenvironment may be potential predictive biomarkers of nivolumab in biliary tract cancers. Further studies are needed to confirm these findings.

Background The 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. Methods Patients 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. Results The 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. Conclusions This 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.

Background The Notch signalling pathway is activated in a variety of malignancies and has been implicated in colorectal cancer progression. One of the first steps in the Notch pathway activation is mediated by γ-secretase, a proteolytic enzyme which produces an activated intracellular Notch (ICN). RO4929097 is a selective inhibitor of γ-secretase. We tested the activity of RO4929097 in patients with metastatic, refractory colorectal cancer. Patients and methods Patients with metastatic colorectal cancer who had received at least two prior lines of systemic chemotherapy were enrolled on the study. Patients were treated with RO4929097 at its recommended phase II dose of 20 mg daily, 3 days on and 4 days off continuously. Cycle length was 28 days. Imaging was performed every two cycles. Archival tissue specimens were stained immunohistochemically for components of the notch pathway: Notch1, ICN and the downstream target HES1. Results Thirty-seven patients were enrolled of whom 33 were evaluable for toxicity and response. Immunohistochemical analysis of archival tissues demonstrated positive staining for the notch receptor as well as intracellular notch and the downstream gene HES1 in the majority of patients. Nevertheless, no objective radiographic responses were observed in this group and only six patients had stable disease as their best response. Median PFS was 1.8 months and median overall survival (OS) was 6.0 months. Conclusion In this study of RO4929097 in patients with refractory metastatic colorectal cancer, no radiographic responses were seen and time to progression was short, which suggests that RO4929097 at the study dose and schedule has minimal single agent activity in this malignancy.