The rise of the FGFR inhibitor in advanced biliary cancer: the next cover of time magazine?

Perioperative and palliative systemic treatments for biliary tract cancer

Due to the fact biliary tract cancer (BTC) is often diagnosed at an advanced stage, thus, not eligible for resection, and due to the aggressive tumor biology, it is considered as one of the cancer types with the worst prognosis. Advances in diagnosis, surgical techniques, and molecular characterization have led to an improvement of the prognosis of BTC patients, recently. Although neoadjuvant therapy is expected to improve surgical outcomes by reducing tumor size, its routine is not well established. The application of neoadjuvant therapy in locally advanced disease may be indicated, the routine use of systemic therapy prior to surgery for cholangiocarcinoma patients with an upfront resectable disease is less well established, but discussed and performed in selected cases. In advanced disease, only combination chemotherapy regimens have been demonstrated to achieve disease control in untreated patients. Molecular profiling of the tumor has demonstrated that many BTC might bear actionable targets, which might be addressed by biological treatments, thus improving the prognosis of the patients. Furthermore, the addition of the immunotherapy to standard chemotherapy might improve the prognosis in a subset of patients. This review seeks to give a comprehensive overview about the role of neoadjuvant as well as palliative systemic treatment approaches and an outlook about novel systemic treatment concept in BTC.

Trilobolide-6-O-isobutyrate exerts anti-tumor effects on cholangiocarcinoma cells through inhibiting JAK/STAT3 signaling pathway

Trilobolide-6-O-isobutyrate exhibits significant antitumor effects on cholangiocarcinoma (CCA) cells by effectively inhibiting the JAK/STAT3 signaling pathway. This study aims to investigate the mechanisms underlying the antitumor properties of trilobolide-6-O-isobutyrate, and to explore its potential as a therapeutic agent for CCA. This study illustrates that trilobolide-6-O-isobutyrate efficiently suppresses CCA cell proliferation in a dose- and time-dependent manner. Furthermore, trilobolide-6-O-isobutyrate stimulates the production of reactive oxygen species, leading to oxidative stress and initiation of apoptosis via the activation of the mitochondrial pathway. Data from xenograft tumor assays in nude mice confirms that TBB inhibits tumor growth, and that there are no obvious toxic effects or side effects in vivo. Mechanistically, trilobolide-6-O-isobutyrate exerts antitumor effects by inhibiting STAT3 transcriptional activation, reducing PCNA and Bcl-2 expression, and increasing P21 expression. These findings emphasizes the potential of trilobolide-6-O-isobutyrate as a promising therapeutic candidate for the treatment of CCA.

Sunitinib in Patients With Breast Cancer With FGFR1 or FGFR2 Amplifications or Mutations: Results From the Targeted Agent and Profiling Utilization Registry Study

PURPOSE

The Targeted Agent and Profiling Utilization Registry Study is a phase II basket trial evaluating the antitumor activity of commercially available targeted agents in patients with advanced cancer and genomic alterations known to be drug targets. Results from cohorts of patients with metastatic breast cancer (BC) with FGFR1 and FGFR2 alterations treated with sunitinib are reported.

METHODS

Eligible patients had measurable disease, Eastern Cooperative Oncology Group performance status 0-2, adequate organ function, and no standard treatment options. Simon's two-stage design was used with a primary end point of disease control (DC), defined as objective response (OR) or stable disease of at least 16 weeks duration (SD16+) according to RECIST v1.1. Secondary end points included OR, progression-free survival, overall survival, duration of response, duration of stable disease, and safety.

RESULTS

Forty patients with BC with FGFR1 (N = 30; amplification only n = 26, mutation only n = 1, both n = 3) or FGFR2 (N = 10; amplification only n = 2, mutation only n = 6, both n = 2) alterations were enrolled. Three patients in the FGFR1 cohort were not evaluable for efficacy; all patients in the FGFR2 cohort were evaluable. For the FGFR1 cohort, two patients with partial response and four with SD16+ were observed for DC and OR rates of 27% (90% CI, 13 to 100) and 7% (95% CI, 1 to 24), respectively. The null hypothesis of 15% DC rate was not rejected (P = .169). No patients achieved DC in the FGFR2 cohort (P = 1.00). Thirteen of the 40 total patients across both cohorts had at least one grade 3-4 adverse event or serious adverse event at least possibly related to sunitinib.

CONCLUSION

Sunitinib did not meet prespecified criteria to declare a signal of antitumor activity in patients with BC with either FGFR1 or FGFR2 alterations. Other treatments and clinical trials should be considered for these patient populations.

Oncogenic activation revealed by FGFR2 genetic alterations in intrahepatic cholangiocarcinomas

BACKGROUND

Except for gene fusions, FGFR2 genetic alterations in intrahepatic cholangiocarcinomas (ICCs) have received limited attention, leaving patients harboring activating FGFR2 gene mutations with inadequate access to targeted therapies.

EXPERIMENTAL DESIGN

We sought to survey FGFR2 genetic alterations in ICC and pan-cancers using fluorescence in situ hybridization and next-generation sequencing. We conducted an analysis of the clinical and pathological features of ICCs with different FGFR2 alterations, compared FGFR2 lesion spectrum through public databases and multicenter data, and performed cellular experiments to investigate the oncogenic potential of different FGFR2 mutants.

RESULTS

FGFR2 gene fusions were identified in 30 out of 474 ICC samples, while five FGFR2 genetic alterations aside from fusion were present in 290 ICCs. The tumors containing FGFR2 translocations exhibited unique features, which we designated as the "FGFR2 fusion subtypes of ICC". Molecular analysis revealed that FGFR2 fusions were not mutually exclusive with other oncogenic driver genes/mutations, whereas FGFR2 in-frame deletions and site mutations often co-occurred with TP53 mutations. Multicenter and pan-cancer studies demonstrated that FGFR2 in-frame deletions were more prevalent in ICCs (0.62%) than in other cancers, and were not limited to the extracellular domain. We selected representative FGFR2 genetic alterations, including in-frame deletions, point mutations, and frameshift mutations, to analyze their oncogenic activity and responsiveness to targeted drugs. Cellular experiments revealed that different FGFR2 genetic alterations promoted ICC tumor growth, invasion, and metastasis but responded differently to FGFR-selective small molecule kinase inhibitors (SMKIs).

CONCLUSIONS

FGFR2 oncogenic alterations have different clinicopathological features and respond differently to SMKIs.

Progression-Free Survival in Patients With Cholangiocarcinoma With or Without FGF/FGFR Alterations: A FIGHT-202 Post Hoc Analysis of Prior Systemic Therapy Response

PURPOSE

Oncogenic fibroblast growth factor receptor (FGFR) gene alterations have been described in patients with cholangiocarcinoma (CCA). This post hoc analysis assessed progression-free survival (PFS) in patients who had received first- or second-line systemic therapy for advanced/metastatic CCA before enrollment in the phase II FIGHT-202 study (ClinicalTrials.gov identifier: NCT02924376).

PATIENTS AND METHODS

Patients with locally advanced or metastatic CCA with FGFR2 fusions/rearrangements (n = 107), other FGF/FGFR alterations (n = 20), or no FGF/FGFR alterations (n = 18) and documented disease progression after at least one systemic cancer therapy before enrollment in FIGHT-202 were assessed. Prior therapy and disease response data were collated from electronic case report forms. PFS was calculated for each prior line of systemic cancer therapy.

RESULTS

Among patients with FGFR2 fusions/rearrangements, other FGF/FGFR alterations, and no FGF/FGFR alterations, respectively, the median PFS with prior first-line systemic therapy was 5.5 months (95% CI, 4.0 to 8.0; n = 102), 4.4 months (2.7 to 7.1; n = 19), and 2.8 months (1.6 to 11.3; n = 16); the median PFS with prior second-line systemic therapy was 4.2 months (3.0 to 5.3; n = 39), 3.0 months (1.1 to 9.9; n = 8), and 5.9 months (2.4 to 12.5; n = 6). The median PFS was 7.0 months (4.9 to 11.1) for patients with FGFR2 fusions/rearrangements (n = 65) with second-line pemigatinib received during the FIGHT-202 trial.

CONCLUSION

In patients with CCA and FGFR2 fusions or rearrangements, second-line treatment with pemigatinib may be associated with longer PFS compared with second-line treatment with systemic therapy received before study enrollment; however, a prospective controlled trial is required to confirm this. The results support the therapeutic potential of pemigatinib previously demonstrated in FIGHT-202.

Systemic Treatment for Metastatic Biliary Tract Cancer: State of the Art and a Glimpse to the Future

Recent years have seen some breakthroughs in the therapeutic landscape of advanced biliary tract cancer (BTC). Firstly, a better understanding of the molecular background of BTC has led to important improvements in the management of these hepatobiliary malignancies, with the advent of targeted agents representing an unprecedented paradigm shift, as witnessed by the FDA approval of pemigatinib and infigratinib for FGFR2-rearranged and ivosidenib in IDH1-mutant cholangiocarcinoma. In addition, several novel treatments are under assessment, including immune checkpoint inhibitors and combination chemotherapies. In the current review, we provide an overview of systemic treatment for metastatic BTC, summarizing recent clinical data on chemotherapy as well as the main results of targeted therapies and immunotherapy.

Comparative Genomic Analysis of Intrahepatic Cholangiocarcinoma: Biopsy Type, Ancestry, and Testing Patterns

BACKGROUND

At diagnosis, the majority of patients with intrahepatic cholangiocarcinoma (IHCC) present with advanced disease and a poor prognosis. Comprehensive genomic profiling (CGP) early in the disease course may increase access to targeted therapies and clinical trials; however, unresolved issues remain surrounding the optimal biopsy type to submit for CGP.

PATIENTS AND METHODS

Mutational frequencies between primary tumor biopsies (Pbx), metastatic biopsies (Mbx), and liquid biopsies (Lbx) in 1,632 patients with IHCC were compared.

RESULTS

Potentially actionable alterations were found in 52%, 34%, and 35% of patients in the Pbx, Mbx, and Lbx cohorts, respectively. In Pbx, Mbx, and Lbx, FGFR2 rearrangements were found in 9%, 6%, and 4%, and IDH1 mutations were identified in 16%, 5%, and 9% patients, respectively. Moreover, alterations in FGFR2 and IDH1 were significantly associated with distinct ancestries, including 2.1-fold enrichment for FGFR2 rearrangements in patients with African ancestry and 1.5-fold enrichment for IDH1 mutations in patients with admixed American (Hispanic) ancestry. Finally, the publication of biomarker-driven clinical trials in IHCC correlated with changing CGP testing patterns. Significant correlations between patient characteristics and IHCC trial disclosures were observed, including a significant decrease from time between biopsy and CGP testing, and more frequent testing of primary versus metastatic samples.

CONCLUSION

Overall, because of the high likelihood of identifying actionable genomic alterations, CGP should be considered for the majority of patients with inoperable IHCC, and Lbx and Mbx can be considered as part of the diagnostic suite.

IMPLICATIONS FOR PRACTICE

Comprehensive genomic profiling (CGP) should be considered for all patients with intrahepatic cholangiocarcinoma (IHCC) or suspected IHCC, as actionable alterations were commonly found in multiple genes and a wide variety of FGFR2 fusion partners were identified. The disclosure of IHCC trial data correlated with increased use of CGP, an encouraging trend that moves new therapeutic options forward for rare cancers with a rare biomarker. Although tissue from the primary lesion may identify actionable alterations at higher rates, CGP of a liquid biopsy or metastatic site can be considered, particularly if the primary tissue block is exhausted.

Management of Intrahepatic Cholangiocarcinoma

Cholangiocarcinoma is a tumor that arises as a result of differentiation of the cholangiocytes and can develop from anywhere in the biliary tree. Subtypes of cholangiocarcinoma are differentiated based on their location in the biliary tree. If diagnosed early these can be resected, but most cases of intrahepatic cholangiocarcinoma present late in the disease course where surgical resection is not an option. In these patients who are poor candidates for resection, a combination of chemotherapy, locoregional therapies like ablation, transarterial chemo and radioembolization, and in very advanced and metastatic disease, external radiation are the available options. These modalities can improve overall disease-free and progression-free survival chances. In this review, we will discuss the risk factors and clinical presentation of intrahepatic cholangiocarcinoma, diagnosis, available therapeutic options, and future directions for management options.

Targeted Therapies in Advanced Cholangiocarcinoma: A Focus on FGFR Inhibitors

Despite advanced diseases continuing to be associated with grim prognoses, the past decade has witnessed the advent of several novel treatment options for cholangiocarcinoma (CCA) patients. In fact, CCA has emerged as a heterogeneous group of malignancies harboring potentially druggable mutations in approximately 50% of cases, and thus, molecularly targeted therapies have been actively explored in this setting. Among these, fibroblast growth factor receptor (FGFR) inhibitors have reported important results, as witnessed by the FDA approval of pemigatinib in previously treated metastatic CCA patients harboring FGFR2 fusion or other rearrangements. Herein, we provide an overview of available evidence on FGFR inhibitors in CCA, especially focusing on the development, pitfalls and challenges of emerging treatments in this setting.

FGFR inhibitors in elderly patients with advanced biliary tract cancer: an unsolved issue

Background: Despite recent advances in the understanding of the molecular landscape of biliary tract cancer (BTC), advanced disease continues to carry a poor prognosis, and the benefit from systemic treatments remains modest. However, BTCs have emerged as malignancies harboring specific potentially druggable aberrations, and thus, several molecularly targeted treatments have been recently tested. Among these, fibroblast growth factor receptor (FGFR) inhibitors have shown interesting results in previously treated BTC patients with advanced diseaseAreas covered: In this review, we aimed to provide an overview of available evidence on FGFR inhibitors in elderly patients with metastatic BTC, especially focusing on subgroup analyses of recently published trials exploring this novel therapeutic approach in these aggressive malignancies.Expert opinion: The FGFR1, FGFR2, and FGFR3 inhibitor pemigatinib has been recently approved by the United States Food and Drug Administration (FDA) in metastatic BTCs harboring FGFR2 fusion or other rearrangement. However, few data are available regarding the use of FGFR inhibitors in elderly BTCs, a patient population that remains seriously under-represented in clinical trials.

Typing FGFR2 translocation determines the response to targeted therapy of intrahepatic cholangiocarcinomas

Chromosomal translocations involving fibroblast growth factor receptor 2 (FGFR2) gene at the breakpoints are common genetic lesions in intrahepatic cholangiocarcinoma (ICC) and the resultant fusion protein products have emerged as promising druggable targets. However, predicting the sensitivity of FGFR2 fusions to FGFR kinase inhibitors is crucial to the prognosis of the ICC-targeted therapy. Here, we report identification of nine FGFR2 translocations out of 173 (5.2%) ICC tumors. Although clinicopathologically these FGFR2 translocation bearing ICC tumors are indistinguishable from the rest of the cohort, they are invariably of the mass-forming type originated from the small bile duct. We show that the protein products of FGFR2 fusions can be classified into three subtypes based on the breaking positions of the fusion partners: the classical fusions that retain the tyrosine kinase (TK) and the Immunoglobulin (Ig)-like domains (n = 6); the sub-classical fusions that retain only the TK domain without the Ig-like domain (n = 1); and the non-classical fusions that lack both the TK and Ig-like domains (n = 2). We demonstrate that cholangiocarcinoma cells engineered to express the classical and sub-classical fusions show sensitivity to FGFR-specific kinase inhibitors as evident by the suppression of MAPK/ERK and AKT/PI3K activities following the inhibitor treatment. Furthermore, the kinase-deficient mutant of the sub-classical fusion also lost its sensitivity to the FGFR-specific inhibitors. Taken together, our study suggests that it is essential to determine the breakpoint and type of FGFR2 fusions in the small bile duct subtype of ICC for the targeted treatment.

Cholangiocarcinoma: shedding light on the most promising drugs in clinical development

Introduction: Cholangiocarcinoma (CCA) is a diverse group of fatal malignancies arising from the biliary tract. Surgical resection with negative margin offers the only potentially curative option. The majority of patients present at locally advanced or metastatic stages, when surgical resection is not feasible, highlighting the significance of systemic therapy. Given the limited effectiveness of traditional chemotherapy regimens in CCA, many investigators have focused on developing novel molecular therapies targeting key aberrant signaling pathways.Areas covered: We present the main genomic aberrations known to play a key role in cholangiocarcinogenesis and discuss promising targeted therapies in clinical development.In October of 2020, a review of the English literature was performed utilizing PubMed and Web of Science databases for the keywords of 'cholangiocarcinoma', 'biliary tract cancer', and 'targeted therapy'.Expert opinion: Unfortunately, despite encouraging results in preclinical studies, the outcome of clinical trials with established targeted therapies like anti-EGFR medications have been discouraging. Currently, agents targeting FGFR2 fusion and IDH1/2 mutations hold great promise for improving the management of CCA. Future studies focused on enhancing our understanding of key aberrant signaling pathways of cholangiocarcinogenesis and the design of homogeneous and biomarker-driven cohorts are key elements of establishing precision medicine in CCA.

Pemigatinib: Hot topics behind the first approval of a targeted therapy in cholangiocarcinoma

Cholangiocarcinoma (CCA) includes a heterogeneous group of malignancies with limited treatment options. Despite recent advances in medical oncology, the prognosis of CCA patients with metastatic disease remains poor, with a median overall survival of less than a year. In the last decade, notable efforts have been made by the CCA medical community in an attempt to improve clinical outcomes of patients, with the development of molecularly targeted therapies in this setting. Among these treatments, the fibroblast growth factor receptor (FGFR) 2 inhibitor pemigatinib has received accelerated approval in April 2020 by the US Food and Drug Administration (FDA) in CCA patients harboring FGFR2 gene fusions or other rearrangements, on the basis of the results of the FIGHT-202 trial, and thus, representing the first molecularly targeted therapy to be approved for the treatment of CCA. However, several issues remain, including the emergence of polyclonal mutations determining resistance to pemigatinib, the identification of biomarkers predictive of response, and the knowledge gaps regarding the role of other FGFR gene aberrations. This review aims to provide an overview of recent development of pemigatinib, especially focusing on the results of the pivotal FIGHT-202 trial, the approval of this FGFR inhibitor, and the future challenges concerning the use of FGFR-directed treatments in CCA patients.

Intrahepatic Cholangiocarcinoma: State of the Art of FGFR Inhibitors

OBJECTIVE

Intrahepatic cholangiocarcinoma (iCCA), the second most common type of primary liver tumor, has an increasing incidence in the past few decades. iCCA is highly malignant, with a 5-year survival rate of approximately 5-10%. Surgical resection is usually the prescribed treatment for patients with early stage iCCA; however, patients are usually in an advanced stage iCCA upon diagnosis. Currently, targeted therapy combined with chemotherapy and other comprehensive treatment measures have been mainly adopted as palliative treatment measures. As a common candidate of targeted therapy, FGFR inhibitors have demonstrated their unique advantages in clinical trials. At present, the prospect of FGFR targeted therapy is encouraging. The landscape of FGFR inhibitors in iCCA is needed to be showed urgently.

METHODS

We searched relative reports of clinical trials on FGFR inhibitors in PubMed as well as Web of Science. We also concluded other available clinical trials of FGFR inhibitors (Data were collected from clinicaltrials.gov).

RESULTS

Several relatively effective targeted drugs are being used in clinical trials. Some preliminary results indicate the outlook of targeted therapy such as BGJ398, TAS120, and HSP90 inhibitors.

CONCLUSIONS

In summary, FGFR targeted therapy has broad prospects for the treatment of iCCA.

Clinicogenomic Analysis of FGFR2-Rearranged Cholangiocarcinoma Identifies Correlates of Response and Mechanisms of Resistance to Pemigatinib

Pemigatinib, a selective FGFR1-3 inhibitor, has demonstrated antitumor activity in FIGHT-202, a phase II study in patients with cholangiocarcinoma harboring FGFR2 fusions/rearrangements, and has gained regulatory approval in the United States. Eligibility for FIGHT-202 was assessed using genomic profiling; here, these data were utilized to characterize the genomic landscape of cholangiocarcinoma and to uncover unique molecular features of patients harboring FGFR2 rearrangements. The results highlight the high percentage of patients with cholangiocarcinoma harboring potentially actionable genomic alterations and the diversity in gene partners that rearrange with FGFR2. Clinicogenomic analysis of pemigatinib-treated patients identified mechanisms of primary and acquired resistance. Genomic subsets of patients with other potentially actionable FGF/FGFR alterations were also identified. Our study provides a framework for molecularly guided clinical trials and underscores the importance of genomic profiling to enable a deeper understanding of the molecular basis for response and nonresponse to targeted therapy. SIGNIFICANCE: We utilized genomic profiling data from FIGHT-202 to gain insights into the genomic landscape of cholangiocarcinoma, to understand the molecular diversity of patients with FGFR2 fusions or rearrangements, and to interrogate the clinicogenomics of patients treated with pemigatinib. Our study highlights the utility of genomic profiling in clinical trials.This article is highlighted in the In This Issue feature, p. 211.

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.

Promises of Fibroblast Growth Factor Receptor-Directed Therapy in Tailored Cancer Treatment

Cancer, one of the deadliest and undefeatable diseases, involves the deregulated growth of cells with the conferment of a high potential to metastasize [...].

Functions of FGFR2 corrupted by translocations in intrahepatic cholangiocarcinoma

Cholangiocarcinoma, originating from the biliary duct, represents a subset of liver cancer. With about 8000 new cases of cholangiocarcinoma diagnosed annually in the U.S., these fall into three categories: intrahepatic, peri-hilar, and extrahepatic cholangiocarcinoma. Arising from the epithelium of the bile duct, intrahepatic cholangiocarcinoma (ICC) is a universally fatal malignancy with very few treatment options. The poor prognosis and lack of molecular targeted therapies highlights ICC as a critical unmet medical need. With advances in sequencing technology, numerous chromosomal translocations have been discovered as drivers in cancer initiation and progression. Particularly in ICC, chromosomal translocations involving Fibroblast Growth Factor Receptor 2 (FGFR2) have been frequently identified, resulting in the creation of oncogenic fusion proteins. At the N-terminus, these fusion proteins share a nearly-identical FGFR2 moiety retaining an intact kinase domain and, at the C-terminus, a dimerization/oligomerization domain provided by different partner genes, including: Periphilin 1 (PPHLN1), Bicaudal family RNA binding protein 1 (BICC1), Adenosylhomocysteinase Like 1 (AHCYL1), and Transforming Acidic Coiled-Coil Containing Protein 3 (TACC3). A number of pre-clinical and clinical trials have shown the effectiveness of FGFR inhibitors in treating FGFR2 fusion-positive ICC patients. However, the efficacy of these inhibitors may be short-lived due to acquired resistance. In this review, we provide an overview of FGFR2 fusions, comparing their structures and mechanism of dimerization, examining the importance of FGFR2 as a partner gene, as well as highlighting the significance of alternative splicing of FGFR2 in these fusion proteins. In addition, we discuss various therapeutic options and their associated potencies in targeting these translocation-induced ICCs.

Sprouty4 correlates with favorable prognosis in perihilar cholangiocarcinoma by blocking the FGFR-ERK signaling pathway and arresting the cell cycle

Background

Perihilar cholangiocarcinoma (PHCC) is the most common subtype of cholangiocarcinoma(CCA). We previously investigated the expression pattern of Sprouty(SPRY) in intrahepatic cholangiocarcinoma(ICC), but the expression and clinical significance of SPRY family members in PHCC are still unknown.

Methods

The expression of SPRY family members(SPRY1-4) was detected in different subtypes of CCA and corresponding adjacent tissues. SPRY4 expression in 142 cases of PHCC was detected by immunohistochemistry, and its clinical significance was evaluated using univariate and multivariate analyses. The functions of SPRY4 in the FGFR-induced proliferation and migration of PHCC cells were investigated through in vitro and in vivo experiments. We further investigated the effects and mechanisms of SPRY4 on FGFR-induced ERK phosphorylation and cell cycle distribution in the presence of FGFR and ERK inhibitors.

Findings

SPRY4 was the only SPRY family member associated with PHCC prognosis, and it was identified as an independent factor predicting favorable prognosis. In PHCC, SPRY4 expression was extensively associated with FGFR2, and its expression can be induced by ectopic FGFR2 activation. Through in vitro and in vivo experiments, we demonstrated that SPRY4 suppressed FGFR-induced proliferation and migration by inhibiting ERK phosphorylation. Moreover, SPRY4 knockdown was shown to decrease the percentage of cells in the G1 phase and promote the percentage of cells in the S and G2/M phases by increasing cyclin D1 expression, which also required FGFR-induced ERK phosphorylation.

Interpretation

High expression of SPRY4 was an independent biomarker of favorable prognosis in PHCC. SPRY4 expression can be induced by ectopic FGFR2 activation in PHCC. SPRY4 arrested the cell cycle at G1 phase and suppressed FGFR-induced proliferation and migration by inhibiting ERK phosphorylation, indicating that SPRY4 may be a potential therapeutic target in PHCC.

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.

Targeted Therapies in Cholangiocarcinoma: Emerging Evidence from Clinical Trials

Cholangiocarcinoma (CCA) is a highly-aggressive malignancy arising from the biliary tree, characterized by a steady increase in incidence globally and a high mortality rate. Most CCAs are diagnosed in the advanced and metastatic phases of the disease, due to the paucity of signs and symptoms in the early stages. This fact, along with the poor results of the local and systemic therapies currently employed, is responsible for the poor outcome of CCA patients and strongly supports the need for novel therapeutic agents and strategies. In recent years, the introduction of next-generation sequencing technologies has opened new horizons for a better understanding of the genetic pathophysiology of CCA and, consequently, for the identification and evaluation of new treatments tailored to the molecular features or alterations progressively elucidated. In this review article, we describe the potential targets under investigation and the current molecular therapies employed in biliary tract cancers. In addition, we summarize the main drugs against CCA under evaluation in ongoing trials and describe the preliminary data coming from these pioneering studies.

The Role of Precision Medicine in the Diagnosis and Treatment of Patients with Rare Cancers

Rare cancers pose unique challenges for patients and their physicians arising from a lack of information regarding the best therapeutic options. Very often, a lack of clinical trial data leads physicians to choose treatments based on small case series or case reports. Precision medicine based on genomic analysis of tumors may allow for selection of better treatments with greater efficacy and less toxicity. Physicians are increasingly using genetics to identify patients at high risk for certain cancers to allow for early detection or prophylactic interventions. Genomics can be used to inform prognosis and more accurately establish a diagnosis. Genomic analysis may also expose therapeutic targets for which drugs are currently available and approved for use in other cancers. Notable successes in the treatment of previously refractory cancers have resulted. New more advanced sequencing technologies, tools for interpretation, and an increasing array of targeted drugs offer additional hope, but challenges remain.

HSP90 Inhibition Drives Degradation of FGFR2 Fusion Proteins: Implications for Treatment of Cholangiocarcinoma

About 15% of intrahepatic cholangiocarcinomas (ICCs) express constitutively active fibroblast growth factor receptor 2 (FGFR2) fusion proteins (FFs) generated by chromosomal translocations. FFs have been nominated as oncogenic drivers because administration of FGFR tyrosine kinase inhibitors (F-TKIs) can elicit meaningful objective clinical responses in patients carrying FF-positive ICC. Thus, optimization of FF targeting is a pressing clinical need. Herein, we report that three different FFs, previously isolated from ICC samples, are heat shock protein 90 (HSP90) clients and undergo rapid degradation upon HSP90 pharmacological blockade by the clinically advanced HSP90 inhibitor ganetespib. Combining catalytic suppression by the F-TKI BGJ398 with HSP90 blockade by ganetespib suppressed FGFR2-TACC3 (transforming acidic coiled-coil containing protein 3) signaling in cultured cells more effectively than either BGJ398 or ganetespib in isolation. The BGJ398 + ganetespib combo was also superior to single agents when tested in mice carrying subcutaneous tumors generated by transplantation of FGFR2-TACC3 NIH3T3 transformants. Of note, FF mutants known to enforce clinical resistance to BGJ398 in ICC patients retained full sensitivity to ganetespib in cultured cells. Conclusion: Our data provide a proof of principle that upfront treatment with the BGJ398 + ganetespib combo improves therapeutic targeting of FGFR2 fusions in an experimental setting, which may be relevant to precision medicine approaches to FF-driven ICC.

Current biologics for treatment of biliary tract cancers

Biliary tract cancers (BTC) is a group of malignancies that arise from the epithelial cells of the biliary tree. These cancers are typically classified by anatomic site of origin: intrahepatic cholangiocarcinoma (IHCC) and extrahepatic cholangiocarcinoma (EHCC), and gallbladder cancer (GBC). To date, complete surgical resection remains the mainstay of treatment especially for earlier stage disease. Unfortunately, most patients present with advanced or metastatic disease, when systemic chemotherapy is the only treatment option. Due to the paucity of effective treatments, BTCs have a dismal prognosis. There is a tremendous need to better understand the disease biology, discover new therapies, and improve clinical outcomes for this challenging disease. Next-generation sequencing has produced a more accurate and detailed picture of the molecular signatures in BTCs. The three BTC histologic subtypes are, in fact, quite molecularly distinct. IHCC commonly contain FGFR2 fusions and IDH 1 and 2 mutations, whereas EHCC and GBC tend to carry mutations in EGFR, HER2, and MAPK pathway. In light of this emerging knowledge, clinical trials have become more biomarker-driven, which allows capturing of subsets of patients that are most likely to respond to certain therapies. Many new and promising targeted therapeutics are currently in the pipeline. Here we review the genetic landscape of BTCs while focusing on new molecular targets and targeted therapeutics currently being investigated in biomarker-driven clinical trials.

Intrahepatic cholangiocarcinoma: current management and emerging therapies

Intrahepatic cholangiocarcinoma (iCCA) is a malignancy with an increasing incidence and a high-case fatality. While surgery offers the best hope at long-term survival, only one-third of tumors are amenable to surgical resection at the time of the diagnosis. Unfortunately, conventional chemotherapy offers limited survival benefit in the management of unresectable or metastatic disease. Recent advances in understanding the molecular pathogenesis of iCCA and the use of next-generation sequencing techniques have provided a chance to identify 'target-able' molecular aberrations. These novel molecular therapies offer the promise to personalize therapy for patients with iCCA and, in turn, improve the outcomes of patients. Area covered: We herein review the current management options for iCCA with a focus on defining both established and emerging therapies. Expert commentary: Surgical resection remains as an only hope for cure in iCCA patients. However, frequently the diagnosis is delayed till advanced stages when surgery cannot be offered; signifying the urge for specific diagnostic tumor biomarkers and targeted therapies. New advances in genomic profiling have contributed to a better understanding of the landscape of molecular alterations in iCCA and offer hope for the development of novel diagnostic biomarkers and targeted therapies.