Preclinical activity of EGFR and MEK1/2 inhibitors in the treatment of biliary tract carcinoma

Overcome Drug Resistance in Cholangiocarcinoma: New Insight Into Mechanisms and Refining the Preclinical Experiment Models

Cholangiocarcinoma (CCA) is an aggressive tumor characterized by a poor prognosis. Therapeutic options are limited in patients with advanced stage of CCA, as a result of the intrinsic or acquired resistance to currently available chemotherapeutic agents, and the lack of new drugs entering into clinical application. The challenge in translating basic research to the clinical setting, caused by preclinical models not being able to recapitulate the tumor characteristics of the patient, seems to be an important reason for the lack of effective and specific therapies for CCA. So, there seems to be two ways to improve patient outcomes. The first one is developing the combination therapies based on a better understanding of the mechanisms contributing to the resistance to currently available chemotherapeutic agents. The second one is developing novel preclinical experimental models that better recapitulate the genetic and histopathological features of the primary tumor, facilitating the screening of new drugs for CCA patients. In this review, we discussed the evidence implicating the mechanisms underlying treatment resistance to currently investigated drugs, and the development of preclinical experiment models for CCA.

Chemoresistance and resistance to targeted therapies in biliary tract cancer: What have we learned?

INTRODUCTION

Biliary tract cancer (BTC), including intra- and extrahepatic cholangiocarcinoma and gallbladder cancer, is a rare and highly difficult to manage human malignancy. Besides late diagnosis and associated unresectability, frequently observed unresponsiveness towards and recurrence following chemotherapy or targeted therapy essentially contribute to the dismal prognosis of BTC patients.

AREAS COVERED

The review provides an update on individual mechanisms involved resistance of BTC towards conventional chemotherapy as well as targeted therapies. We review the distinct mechanisms of pharmacoresistance (MPRs) which have been defined in BTC cells on a molecular basis and examine the specific consequences for the various approaches of chemo-, targeted or immunomodulatory therapies.

EXPERT OPINION

Based on currently available experimental and clinical data, the present knowledge about these MPRs in BTCs are summarized. While some possible tactics for overcoming these mechanisms of resistance have been investigated, a BTC-specific and efficient approach based on comprehensive in vitro and in vivo experimental systems is not yet available. Additionally, a reliable monitoring of therapy-relevant cellular changes needs to be established which allows for choosing the optimal drug (combination) before and/or during pharmacological therapy.

Molecular Landscape and Therapeutic Strategies in Cholangiocarcinoma: An Integrated Translational Approach towards Precision Medicine

Cholangiocarcinomas (CCAs) are heterogeneous biliary tract malignancies with dismal prognosis, mainly due to tumor aggressiveness, late diagnosis, and poor response to current therapeutic options. High-throughput technologies have been used as a fundamental tool in unveiling CCA molecular landscape, and several molecular classifications have been proposed, leading to various targeted therapy trials. In this review, we aim to analyze the critical issues concerning the status of precision medicine in CCA, discussing molecular signatures and clusters, related to both anatomical classification and different etiopathogenesis, and the latest therapeutic strategies. Furthermore, we propose an integrated approach comprising the CCA molecular mechanism, pathobiology, clinical and histological findings, and treatment perspectives for the ultimate purpose of improving the methods of patient allocations in clinical trials and the response to personalized therapies.

Angiogenesis in biliary tract cancer: targeting and therapeutic potential

Introduction: Biliary Tract Cancer (BTC) is a heterogeneous group of malignant neoplasms with a complex molecular pathogenesis. The prognosis of metastatic disease is dramatically dismal and therapeutic options are scarce. Systemic chemotherapy is the gold standard for the metastatic disease. However, because of the disappointing results with conventional chemotherapy, investigators have turned to new biological therapeutic options targeting the main molecular pathways, neo-angiogenesis, involved in the disease pathogenesis.Areas covered: This paper examines the rationale of using antiangiogenic therapies in this setting, evaluates the therapeutic implications, and highlights ongoing studies and future perspectives. A Pubmed systematic review of preclinical and clinical data was performed which enabled the composition of this paper.Expert opinion: Amore in-depth understanding of the interplay between the neo-angiogenesis pathways, and the microenvironment will could propel the design new therapeutic strategies. Nowadays, the combination of antiangiogenic drugs and immune check-point inhibitors looks promising, but further, more comprehensive data are necessary to gain afuller picture. In an era of novel technologies and techniques, which includes radiomics, the challenge is to identify the biomarkers of response to antiangiogenic drugs which will permit the selection of patients that are more likely to respond to antiangiogenic therapies.

Evolution of the Experimental Models of Cholangiocarcinoma

Cholangiocarcinoma (CCA) is a rare, aggressive disease with poor overall survival. In advanced cases, surgery is often not possible or fails; in addition, there is a lack of effective and specific therapies. Multidisciplinary approaches and advanced technologies have improved the knowledge of CCA molecular pathogenesis, highlighting its extreme heterogeneity and high frequency of genetic and molecular aberrations. Effective preclinical models, therefore, should be based on a comparable level of complexity. In the past years, there has been a consistent increase in the number of available CCA models. The exploitation of even more complex CCA models is rising. Examples are the use of CRISPR/Cas9 or stabilized organoids for in vitro studies, as well as patient-derived xenografts or transgenic mouse models for in vivo applications. Here, we examine the available preclinical CCA models exploited to investigate: (i) carcinogenesis processes from initiation to progression; and (ii) tools for personalized therapy and innovative therapeutic approaches, including chemotherapy and immune/targeted therapies. For each model, we describe the potential applications, highlighting both its advantages and limits.

Emerging pathways for precision medicine in management of cholangiocarcinoma

Cholangiocarcinoma (CCA) is the second most common biliary tract malignancy with a dismal prognosis. Surgical resection with a negative microscopic margin offers the only hope for long-term survival. However, the majority of patients present with advanced disease not amenable to curative resection, mainly due to late presentation and aggressive nature of the disease. Unfortunately, due to the heterogeneous nature of CCA as well as limitations of available chemotherapy medications, traditional chemotherapy regimens offer limited survival benefit. Recent advances in genomic studies and next-generation sequencing techniques have assisted in better understanding of cholangiocarcinogenesis and identification of potential aberrant signaling pathways. Targeting the specific genomic abnormalities via novel molecular therapies has opened a new avenue in management of CCA with encouraging results in preclinical studies and early clinical trials. In this review, we present emerging therapies for precision medicine in CCA.

Genetic analysis in the clinical management of biliary tract cancer

Biliary tract cancer (BTC) is clinically and pathologically heterogeneous and responds inadequately to treatment. A small section of patients develop resectable disease, although the relapse rates are high; the benefits of adjuvant capecitabine chemotherapy for BTC are now understood, and gemcitabine-based combination chemotherapy is the first line of therapeutic strategy for BTC; however, alternative therapy for BTC is not known. Genomic profiling can provide detailed information regarding the carcinogenesis, identification, and therapy for BTC. Currently, confirmed restorative targets for BTC are lacking. In this review, we aimed to analyze the preclinical and clinical implications of a spectrum of genomic alterations associated with new potentially remedial targets. We focused on eight draggable genes for BTC, which were described as having evidence of therapeutic impact (evidence level 2A-3B) based on the clinical practice guidance for next-generation sequencing in cancer diagnosis and treatment; these include ERBB2, NTRK1, RNF43, CDK6, CDKN2B, FGFR2, IDH1, and IDH2. Moreover, some of the BTC present microsatellite instability, hypermutation, and germline variants, which we also reviewed. Finally, we discussed the therapeutic options based on the next-generation sequencing findings in BTC. Studies have demonstrated that BTC includes subgroups with individually distinct driver mutations, most of which will be targeted with new treatment plans.

Signalling networks in cholangiocarcinoma: Molecular pathogenesis, targeted therapies and drug resistance

Cholangiocarcinoma (CCA) is a deadly disease. While surgery may attain cure in a minor fraction of cases, therapeutic options in either the adjuvant or advanced setting are limited. The possibility of advancing the efficacy of therapeutic approaches to CCA relies on understanding its molecular pathogenesis and developing rational therapies aimed at interfering with oncogenic signalling networks that drive and sustain cholangiocarcinogenesis. These efforts are complicated by the intricate biology of CCA, which integrates not only the driving force of tumour cell-intrinsic alterations at the genetic and epigenetic level but also pro-tumorigenic cues conveyed to CCA cells by different cell types present in the rich tumour stroma. Herein, we review our current understanding of the mechanistic bases underpinning the activation of major oncogenic pathways causative of CCA pathogenesis. We subsequently discuss how this knowledge is being exploited to implement rationale-based and genotype-matched therapeutic approaches that predictably will radically transform CCA clinical management in the next decade. We conclude by highlighting the mechanisms of therapeutic resistance in CCA and reviewing innovative approaches to combat resistance at the preclinical and clinical level.

Role of ErbB/HER family of receptor tyrosine kinases in cholangiocyte biology

The ErbB/HER family comprises four distinct tyrosine kinase receptors, EGFR/ErbB1/HER1, ErbB2/HER2, ErbB3/HER3, and ErbB4/HER4, which trigger intracellular signals at the origin of essential cellular functions, including differentiation, proliferation, survival, and migration. Epithelial cells, named cholangiocytes, that line intrahepatic and extrahepatic bile ducts, contribute substantially to biliary secretory functions and bile transport. Although ErbB receptors have been widely studied in cholangiocarcinoma (CCA), a malignancy of the biliary tract, knowledge of these receptors in biliary epithelium physiology and in non-malignant cholangiopathies is far from complete. Current knowledge suggests a role for epidermal growth factor receptor (EGFR) in cholangiocyte specification and proliferation, and in hepatocyte transdifferentiation into cholangiocytes during liver regeneration to restore biliary epithelium integrity. High expression and activation of EGFR and/or ErbB2 were recently demonstrated in biliary lithiasis and primary sclerosing cholangitis, two cholangiopathies regarded as risk factors for CCA. In CCA, ErbB receptors are frequently overexpressed, leading to tumor progression and low prognosis. Anti-ErbB therapies were efficient only in preclinical trials and have suggested the existence of resistance mechanisms with the need to identify predictive factors of therapy response. This review aims to compile the current knowledge on the functions of ErbB receptors in physiology and physiopathology of the biliary epithelium. (Hepatology 2018;67:762-773).

Efficacy and safety of trametinib in Japanese patients with advanced biliary tract cancers refractory to gemcitabine

Gemcitabine‐based therapy remains the mainstay of treatment for patients with biliary tract cancers (BTCs) with no second‐line treatment(s) established yet. Aberrant activation of the MAPK pathway in patients with BTC indicates its importance in BTC. Trametinib is a potent, highly selective, allosteric non‐competitive inhibitor of MEK1/MEK2. In this phase IIa open‐label, single‐arm study, we investigated the efficacy and safety of trametinib in Japanese patients with advanced BTC refractory to gemcitabine‐based therapy. All patients received oral trametinib 2 mg once daily until progressive disease (PD), death, or unacceptable toxicity. The primary objective was to determine the 12‐week non‐PD rate. Secondary assessments included safety, progression‐free survival (PFS), overall survival, and overall response rate. Targeted exome sequencing was used to identify biomarkers for sensitivity or resistance to trametinib monotherapy. Twenty patients (median age, 61.5 years) with carcinoma of gall bladder (40%), intrahepatic (25%) or extrahepatic (30%) bile duct, and ampulla of Vater (5%) were enrolled. The non‐PD rate at week 12 was 10% (95% confidence interval, 1.2‐31.7); it did not reach the threshold rate of 25%. Median PFS was 10.6 weeks (95% confidence interval, 4.6‐12.1) and 1‐year overall survival was 20.0%. Stable disease and PD were observed in 13 (65%) and seven (35%) patients, respectively. No new safety signals were reported. Although the primary end‐point was not met, prolonged PFS was observed in one patient having six somatic variants including synonymous NF1 exon 12 splice variant and a loss‐of‐function variant in ARID1A. Efforts to understand responsive mutations and sensitivity to targeted therapies are warranted. This trial was registered with ClinicalTrials.gov: NCT01943864.

INST OX-05-024: first line gemcitabine, oxaliplatin, and erlotinib for primary hepatocellular carcinoma and bile duct cancers: a multicenter Phase II trial

Hepatocellular Carcinoma (HCC) incidence is increasing in the USA. Gemcitabine (G) and oxaliplatin (O) are active in HCC and biliary duct cancer (BDC). Erlotinib (E) is an EGFR tyrosine kinase inhibitor (TKI) with known activity against both. We sought to evaluate the efficacy of the combination G+O+E. Patients with either of the two diagnosis were treated in a phase II trial. Simons 2 stage design was used. A disease‐control rate (DCR), complete response (CR) + partial response (PR)+ stable disease (SD) at 24 weeks of ≤20% and >40% (P0 and P1 of 0.2 and 0.4, respectively) were set as undesirable (null) and desirable results. 26 HCC and 7 BDC patients were accrued. In HCC, 1 PR, 10 SD, and 9 PDs were seen. DCR in HCC was 42%. Among seven (7) patients with BDC, one patient was not evaluable; one achieved a long lasting PR, and five patients had SD and DCR was 86%. Median overall survival (OS) times and progression‐free survivals (PFS) were 196 and 149 days in HCC and 238 days and not reached in BDC. PFS at 26 weeks in HCC was 41% and at 21 weeks in BDC was 60%. Grade 3 toxicities in >5% of patients were fatigue (12.9%), neutropenia (9.6%), thrombocytopenia (9.6%), and diarrhea (6.4%). G+O+E exceeded both preset P0a and P1 of the primary objective with a PFS of 41% at 26 weeks for HCC and preliminary BDC data may warrant further investigations.

Targeting Angiogenesis in Biliary Tract Cancers: An Open Option

Biliary tract cancers (BTCs) are characterized by a bad prognosis and the armamentarium of drugs for their treatment is very poor. Although the inflammatory status of biliary tract represents the first step in the cancerogenesis, the microenvironment also plays a key role in the pathogenesis of BTCs, promoting tumor angiogenesis, invasion and metastasis. Several molecules, such as vascular endothelial growth factor (VEGF) and fibroblast growth factor (FGF), are involved in the angiogenesis process and their expression on tumor samples has been explored as prognostic marker in both cholangiocarcinoma and gallbladder cancer. Recent studies evaluated the genomic landscape of BTCs and evidenced that aberrations in several genes enrolled in the pro-angiogenic signaling, such as FGF receptor-2 (FGFR-2), are characteristic of BTCs. New drugs targeting the signaling pathways involved in angiogenesis have been tested in preclinical studies both in vitro and in vivo with promising results. Moreover, several clinical studies tested monoclonal antibodies against VEGF and tyrosine kinase inhibitors targeting the VEGF and the MEK/ERK pathways. Herein, we evaluate both the pathogenic mechanisms of BTCs focused on angiogenesis and the preclinical and clinical data available regarding the use of new anti-angiogenic drugs in these malignancies.