The HER3 pathway as a potential target for inhibition in patients with biliary tract cancers

HER2-targeted therapies beyond breast cancer - an update

The receptor tyrosine-kinase HER2 (also known as ErbB2) is a well-established therapeutic target in patients with breast or gastric cancer selected on the basis of HER2 overexpression on immunohistochemistry and/or ERBB2 amplification on in situ hybridization. With advances in cancer molecular profiling and increased implementation of precision medicine approaches into oncology practice, actionable HER2 alterations in solid tumours have expanded to include ERBB2 mutations in addition to traditional HER2 overexpression and ERBB2 amplification. These various HER2 alterations can be found in solid tumour types beyond breast and gastric cancer, although few HER2-targeted therapeutic options have been established for the other tumour types. Nevertheless, during the 5 years since our previous Review on this topic was published in this journal, obvious and fruitful progress in the development of HER2-targeted therapies has been made, including new disease indications, innovative drugs with diverse mechanisms of action and novel frameworks for approval by regulatory authorities. These advances have culminated in the recent histology-agnostic approval of the anti-HER2 antibody-drug conjugate trastuzumab deruxtecan for patients with HER2-overexpressing solid tumours. In this new Review, we provide an update on the current development landscape of HER2-targeted therapies beyond breast cancer, as well as anticipated future HER2-directed treatment strategies to overcome resistance and thereby improve efficacy and patient outcomes.

Revolutionizing anti-HER2 therapies for extrahepatic cholangiocarcinoma and gallbladder cancer: Current advancements and future perspectives

Biliary tract cancers (BTCs) encompass a heterogeneous group of rare tumors, including intrahepatic cholangiocarcinoma (iCCA), extrahepatic cholangiocarcinoma (eCCA), gallbladder cancer (GBC) and ampullary cancer (AC). The present first-line palliative treatment regimen comprises gemcitabine and cisplatin in combination with immunotherapy based on two randomized controlled studies. Despite the thorough investigation of these palliative treatments, long-term survival remains low. Moving beyond conventional chemotherapies and immunotherapies, the realm of precision medicine has demonstrated remarkable efficacy in malignancies such as breast and gastric cancers, characterized by notable HER2 overexpression rates. In the context of biliary tract cancer, significant HER2 alterations are observed, particularly within eCCA and GBC, heightening the interest in precision medicine. Various anti-HER2 therapies, including trastuzumab, pertuzumab, trastuzumab-deruxtecan, zanidatamab and neratinib, have undergone investigation. The objective of this review is to summarize the current evidence and outline future directions of targeted HER2 treatment therapy in patients with biliary tract tumors, specially extrahepatic cholangiocarcinoma and gallbladder cancer.

Molecular diagnostics and biomarkers in cholangiocarcinoma

Regardless of anatomic origin, cholangiocarcinoma is generally an aggressive malignancy with a relatively high case fatality. Surgical resection with curative intent remains the best opportunity to achieve meaningful long-term survival. Most patients present, however, with advanced disease and less than 20% of patients are candidates for surgical resection. Unfortunately, even patients who undergo resection have a 5-year survival that ranges from 20 to 40%. Biomarkers are indicators of normal, pathologic, or biologic responses to an intervention and can range from a characteristic (i.e., blood pressure reading which can detect hypertension) to specific genetic mutations or proteins (i.e., carcinoembryonic antigen level). Novel biomarkers and improved molecular diagnostics represent an attractive opportunity to improve detection as well as to identify novel therapeutic targets for patients with cholangiocarcinoma. We herein review the latest advances in molecular diagnostics and biomarkers related to the early detection and treatment of patients with cholangiocarcinoma.

Molecular-driven treatment for biliary tract cancer: the promising turning point

INTRODUCTION

In the past, targeted therapies have not shown positive results as they have been used without adequate molecular selection of patients with biliary tract cancer (BTC). This has led to an expansion of research on characteristics and molecular selection to identify new effective strategies in this setting. Improved knowledge of the molecular biology of these neoplasms has highlighted their extraordinary heterogeneity and has made it possible to identify targetable gene alterations, including fibroblast growth factor receptor (FGFR) 2 gene fusions, and isocitrate dehydrogenase (IDH) mutations. The FDA recently approved ivosidenib and pemigatinib for the treatment of BTCs.

AREAS COVERED

We review data in the literature regarding targeted therapies for the treatment of BTCs, as well as on the prospects deriving from the extraordinary molecular heterogeneity of these neoplasms.

EXPERT OPINION

At present, it is essential to evaluate the expression of the genetic alterations expressed by these neoplasms to offer patients an increasingly personalized therapeutic approach. Studies are needed to better define the limits and potentials of targeted therapies and their role in the therapeutic algorithm to improve the poor prognosis of these patients.

Targeted therapies for gallbladder cancer: an overview of agents in preclinical and clinical development

Introduction: Gallbladder cancer (GC) is a rare malignancy with a dismal prognosis. When diagnosed early enough, it can be cured by surgical removal. Unfortunately, only few GC patients can be amenable to surgery, though, with a high relapse rate. Conventional chemotherapy remains the golden standard for unresectable or metastatic GC, both in the first and second-line settings, even if leading to a fair outcome improvement.Areas covered: In recent years, according to the concept of 'precision medicine', new potential molecular targets have been examined. We provided a general outline of the current first- and second-line chemotherapies. New therapeutic possibilities are also reviewed, particularly HER2, EGFR, VEGF, TKI, MEK and BRAF inhibitors, and immunotherapy. Furthermore, published clinical trials are utilized to analyze the principal drug effectiveness in GC.Expert opinion: GC is characterized by vast cancer heterogeneity and individual's efficacy to different drugs. The ongoing trials have the potentiality of reshaping the landscape of systemic treatments for GC in the very next years. Nowadays, amongst therapeutic combinations, the addition of ICIs to chemotherapy has yielded encouraging results needing confirmation. In the next future, systematic implementation of gene profiling and further explorations of combination therapies will likely change the treatment scenario.

A Phase Ib Study of NUC-1031 in Combination with Cisplatin for the First-Line Treatment of Patients with Advanced Biliary Tract Cancer (ABC-08)

BACKGROUND

Cisplatin/gemcitabine is standard first-line treatment for patients with advanced biliary tract cancer (ABC). NUC-1031 (phosphoramidate transformation of gemcitabine) is designed to enhance efficacy by maximizing intratumoral active metabolites.

METHODS

Patients with untreated ABC, Eastern Cooperative Oncology Group performance status 0-1 received NUC-1031 (625 or 725 mg/m2 ) and cisplatin (25 mg/m2 ) on days 1 and 8, every 21 days. Primary objectives were safety and maximum tolerated dose; secondary objectives were objective response rate (ORR), pharmacokinetics, progression-free survival (PFS), and overall survival (OS).

RESULTS

Twenty-one patients (median age 61 years, n = 13 male; 17 cholangiocarcinoma, 2 ampullary, and 2 gallbladder cancer) received NUC-1031 625 mg/m2 (n = 8 and expansion n = 7; median six cycles) or 725 mg/m2 (n = 6; median 7.5 cycles). Treatment was well tolerated; most common treatment-emergent grade 3-4 adverse events occurring in more than one patient with 625 mg/m2 NUC-1031 were increased gamma-glutamyl transferase (GGT), 40%; alanine aminotransferase, 20%; bilirubin, 13%; neutropenia, 27%; decreased white cell count, 20%; thrombocytopenia, 13%; nausea, 13%; diarrhea, 13%; fatigue, 13%; and thrombus, 20% and with 725 mg/m2 , increased GGT, 67%, and fatigue, 33%. NUC-1031 725 mg/m2 was selected as the recommended dose with cisplatin in ABC. ORR was 33% (one complete response, six partial responses), DCR was 76%, median PFS was 7.2 months (95% confidence interval [CI], 4.3-10.1), and median OS was 9.6 months (95% CI, 6.7-13.1). The median estimates of area under the plasma concentration-time curve from time 0 to last measurable time and maximum concentration were highest for NUC-1031 (218-324 μg•h/mL and 309-889 μg/mL, respectively) and lowest for di-fluoro-deoxycytidine (0.47-1.56 μg•h/mL and 0.284-0.522 μg/mL, respectively).

CONCLUSION

This is the first study reporting on the combination of NUC-1031 with cisplatin in ABC and demonstrated a favorable safety profile; 725 mg/m2 NUC-1031 in combination with cisplatin is undergoing phase III trial evaluation in ABC. (ClinicalTrials.gov ID: NCT02351765; EudraCT ID: 2015-000100-26).

IMPLICATIONS FOR PRACTICE

The prognosis for patients with advanced biliary tract cancer (ABC) is approximately 1 year, and new treatment options are required. The cisplatin/gemcitabine combination is standard first-line treatment for patients with ABC. NUC-1031 is a phosphoramidate transformation of gemcitabine and is designed to enhance efficacy by maximizing intratumoral active metabolites. This phase Ib study (ABC-08) demonstrated a favorable safety profile of NUC-1031 in combination with cisplatin for the first-line treatment of patients with ABC, and 725 mg/m2 NUC-1031 was recommended in combination with cisplatin for phase III trial evaluation; the NuTide:121 global randomized study is currently enrolling.

Current and New Biomarkers for Early Detection, Prognostic Stratification, and Management of Gallbladder Cancer Patients

Gallbladder cancer (GBC) is an aggressive disease that shows evident geographic variation and is characterized by a poor prognosis, mainly due to the late diagnosis and ineffective treatment. Genetic variants associated with GBC susceptibility, including polymorphisms within the toll-like receptors TLR2 and TLR4, the cytochrome P450 1A1 (CYP1A1), and the ATP-binding cassette (ABC) transporter ABCG8 genes, represent promising biomarkers for the stratification of patients at higher risk of GBC; thus, showing potential to prioritize cholecystectomy, particularly considering that early diagnosis is difficult due to the absence of specific signs and symptoms. Similarly, our better understanding of the gallbladder carcinogenic processes has led to identify several cellular and molecular events that may influence patient management, including HER2 aberrations, high tumor mutational burden, microsatellite instability, among others. Despite these reports on interesting and promising markers for risk assessment, diagnosis, and prognosis; there is an unmet need for reliable and validated biomarkers that can improve the management of GBC patients and support clinical decision-making. This review article examines the most potentially significant biomarkers of susceptibility, diagnosis, prognosis, and therapy selection for GBC patients, highlighting the need to find and validate existing and new molecular biomarkers to improve patient outcomes.

Experimental HER2- targeted therapies for biliary tract cancer

Introduction: Biliary tract cancers (BTCs) constitute a heterogeneous group of poor-prognosis solid tumors with limited treatment options. In the last decade, global efforts have tried to identify therapeutic targets by genomic profiling of BTC, unveiling several genetic aberrations that could play a prognostic and/or a predictive role in these malignancies.Areas covered: In this review, we will present an overview regarding the role of HER2 targeted therapies in BTC, with a particular focus on clinical studies carried out in this field to date and ongoing trials. A literature search was conducted in August 2020 of Pubmed/Medline, Cochrane library and Scopus databases for published preclinical and clinical studies; moreover, abstract of international cancer meetings (AACR, ASCO, and ESMO) were reviewed.Expert opinion: Despite recent advances in medical oncology, the overall survival of BTC patients remains low and there is an urgent need for novel and more effective treatments. Although HER2 blockade has been suggested to induce durable tumor responses in selected subjects with BTC, controversial results have been reported so far and data from ongoing prospective clinical trials are awaited to further clarify the role of anti-HER2 therapies in BTC.

Molecular Profiling in Daily Clinical Practice: Practicalities in Advanced Cholangiocarcinoma and Other Biliary Tract Cancers

BACKGROUND

Molecular profiling is becoming increasingly relevant in the management of patients with advanced cancer; to identify targetable aberrations and prognostic markers to enable a precision medicine strategy.

METHODS

Eligible patients were those diagnosed with advanced biliary tract cancer (BTC) including intrahepatic (iCCA) and extrahepatic cholangiocarcinoma (eCCA), gallbladder cancer (GBC), and ampullary carcinoma (Amp) who underwent molecular profiling between April 2017 and June 2020 based on analysis of either tumour samples (FoundationOne CDx®/Oncomine® platforms) or ctDNA (FoundationOne Liquid® platform (Foundation Medicine, Cambridge, MA, USA)). Baseline patient characteristics and molecular profiling outcomes were extracted. The primary aim was to describe sample failure rate. Secondary aims included description of reason for sample failure, summary of findings derived from molecular profiling, and assessment of concordance between paired tissue and ctDNA samples.

RESULTS

A total of 149 samples from 104 individual patients diagnosed with advanced BTC were identified and eligible for this analysis: 68.2% iCCA, 100% advanced stage; 94.2% received palliative therapy. The rate of sample failure was 26.8% for tissue and 15.4% for ctDNA; p-value 0.220, predominantly due to insufficient (defined as <20%) tumour content in the sample (the reason for 91.2% of tissue sample failure). Of the 112 samples successfully analysed, pathological molecular findings were identified in the majority of samples (88.4%) and identification of pathological findings using ctDNA, was possible regardless of whether the patient was on active treatment at time of blood acquisition or not (p-value 1.0). The rate of targetable alterations identified was 40.2% across all successfully-analysed samples (39 iCCA; 6 non-iCCA): IDH1 mutations (19.1% of individual patients), FGFR2 alterations (10.1% and 5.6% of individual patients had FGFR2 fusions and mutations, respectively); 10.6% of all patients (12.4% of patients with successfully analysed samples) entered trials with matched targeted therapies as a consequence. Concordance of findings for paired tissue and paired tissue-ctDNA was high (3/3; 100% and 6/6; 100%, respectively). Twelve ctDNA samples were taken prior to palliative treatment initiation, median maximum mutant allele frequency (MAF) was 0.47 (range 0.21-19.8); no significant association between reported maximum MAF and progression-free survival (PFS) or overall survival (OS) (all Cox regression p-values > 0.273). A total of 15 patients (16.6%) harboured alterations in DNA damage repair (DDR) genes; when treated with platinum-based chemotherapy, there was a trend towards increased partial response rate (21.4% vs. 15.9%; p-value 0.653), radiological benefit rate (64.3% vs. 36.2%; p-value 0.071), and longer OS (median OS 20.4 months (95% CI 7.9-26.7) vs. 13.3 (95 CI 11.0-16.4); Cox Regression HR 0.79 (95% CI 0.39-1.61), p-value 0.527).

CONCLUSIONS

Molecular profiling is of use for identification of novel therapeutic strategies for patients with advanced BTC (mainly iCCA). One in four archived tissue samples may have insufficient tumour content for molecular profiling; ctDNA-based approaches may overcome these obstacles.

Circulating Tumor DNA in Biliary Tract Cancer: Current Evidence and Future Perspectives

Peripheral blood of cancer patients "physiologically" presents cells and cellular components deriving from primary or metastatic sites, including circulating tumor cells (CTCs), circulating free DNA (cfDNA) and exosomes containing proteins, lipids and nucleic acids. The term circulating tumor DNA (ctDNA) indicates the part of cfDNA which derives from primary tumors and/or metastatic sites, carrying tumor-specific genetic or epigenetic alterations. Analysis of ctDNA has enormous potential applications in all stages of cancer management, including earlier diagnosis of cancer, identification of driver alterations, monitoring of treatment response and detection of resistance mechanisms. Thus, ctDNA has the potential to profoundly change current clinical practice, by moving from tissue to peripheral blood as a source of information. Herein, we review current literature regarding the potential role for ctDNA in biliary tract cancer (BTC) patients, with a particular focus on state-of-the-art techniques and future perspectives of this highly aggressive disease.

ErBb Family Proteins in Cholangiocarcinoma and Clinical Implications

The erythroblastic leukemia viral oncogene homolog (ErBb) family consists of the receptor tyrosine kinases (RTK) epidermal growth factor receptor (EGFR; also called ERBB1), ERBB2, ERBB3, and ERBB4. This family is closely associated with the progression of cholangiocarcinoma (CC) through the regulation of cellular networks, which are enhanced during tumorigenesis, metastasis, and chemoresistance. Additionally, the constitutive activation of cellular signaling by the overexpression and somatic mutation-mediated alterations conferred by the ErBb family on cholangiocarcinoma and other cancers enhances tumor aggressiveness and chemoresistance by contributing to the tumor microenvironment. This review summarizes the recent findings on the molecular functions of the ErBb family and their mutations during the progression of cholangiocarcinoma. It also discusses the developments and applications of various devising strategies for targeting the ErBb family through different inhibitors in various stages of clinical trials, which are essential for improving targeted clinical therapies.

Molecular targeted therapies: Ready for "prime time" in biliary tract cancer

The prognosis for patients with biliary tract cancers (cholangiocarcinoma and gallbladder cancer) is poor, while the incidence of these cancers is increasing. Most patients are diagnosed with advanced disease when treatment options are limited to palliative approaches, mainly focused on chemotherapy. In recent years, novel treatment targets of relevance to biliary tract cancers, mainly present in patients with intrahepatic cholangiocarcinoma, have been identified and are rapidly changing the field. These include fibroblast growth factor receptor (FGFR) fusions and isocitrate dehydrogenase (IDH)-1 and -2 mutations which are each present in around 10-20% of patients with intrahepatic cholangiocarcinoma. In addition, inhibition of other pathways/molecules is currently being explored, including human epidermal growth factor receptor (HER) family members, the Wnt pathway, neurotropic tyrosine kinase receptor (NTRK) fusions and BRAF mutations. The IDH1 inhibitor ivosidenib has already been tested in a phase III clinical trial in pretreated cholangiocarcinoma and showed benefit in terms of progression-free survival. Multiple FGFR inhibitors have consistently shown high response rates in phase II/III trials, especially for patients harbouring FGFR2 fusions. Herein, we provide an overview of the status of targeted therapies in biliary tract cancers, discussing the current clinical development of IDH and FGFR inhibitors in detail, as well as reviewing current caveats and future steps.