Molecular targeting of HER2-overexpressing biliary tract cancer cells with trastuzumab emtansine, an antibody–cytotoxic drug conjugate

Quantitative systems pharmacology modeling of HER2-positive metastatic breast cancer for translational efficacy evaluation and combination assessment across therapeutic modalities

HER2-positive (HER2+) metastatic breast cancer (mBC) is highly aggressive and a major threat to human health. Despite the significant improvement in patients' prognosis given the drug development efforts during the past several decades, many clinical questions still remain to be addressed such as efficacy when combining different therapeutic modalities, best treatment sequences, interindividual variability as well as resistance and potential coping strategies. To better answer these questions, we developed a mechanistic quantitative systems pharmacology model of the pathophysiology of HER2+ mBC that was extensively calibrated and validated against multiscale data to quantitatively predict and characterize the signal transduction and preclinical tumor growth kinetics under different therapeutic interventions. Focusing on the second-line treatment for HER2+ mBC, e.g., antibody-drug conjugates (ADC), small molecule inhibitors/TKI and chemotherapy, the model accurately predicted the efficacy of various drug combinations and dosing regimens at the in vitro and in vivo levels. Sensitivity analyses and subsequent heterogeneous phenotype simulations revealed important insights into the design of new drug combinations to effectively overcome various resistance scenarios in HER2+ mBC treatments. In addition, the model predicted a better efficacy of the new TKI plus ADC combination which can potentially reduce drug dosage and toxicity, while it also shed light on the optimal treatment ordering of ADC versus TKI plus capecitabine regimens, and these findings were validated by new in vivo experiments. Our model is the first that mechanistically integrates multiple key drug modalities in HER2+ mBC research and it can serve as a high-throughput computational platform to guide future model-informed drug development and clinical translation.

Ex vivo liver resection and auto-transplantation and special systemic therapy in perihilar cholangiocarcinoma treatment

This editorial contains comments on the article "Systematic sequential therapy for ex vivo liver resection and autotransplantation: A case report and review of literature" in the recent issue of World Journal of Gastrointestinal Surgery. It points out the actuality and importance of the article and focuses primarily on the role and place of ex vivo liver resection and autotransplantation (ELRAT) and systemic therapy, underlying molecular mechanisms for targeted therapy in perihilar cholangiocarcinoma (pCCA) management. pCCA is a tough malignancy with a high proportion of advanced disease at the time of diagnosis. The only curative option is radical surgery. Surgical excision and reconstruction become extremely complicated and not always could be performed even in localized disease. On the other hand, ELRAT takes its place among surgical options for carefully selected pCCA patients. In advanced disease, systemic therapy becomes a viable option to prolong survival. This editorial describes current possibilities in chemotherapy and reveals underlying mechanisms and projections in targeted therapy with kinase inhibitors and immunotherapy in both palliative and adjuvant settings. Fibroblast grow factor and fibroblast grow factor receptor, human epidermal growth factor receptor 2, isocitrate dehydrogenase, and protein kinase cAMP activated catalytic subunit alpha (PRKACA) and beta (PRKACB) pathways have been actively investigated in CCA in last years. Several agents were introduced and approved by the Food and Drug Administration. They all demonstrated meaningful activity in CCA patients with no global change in outcomes. That is why every successfully treated patient counts, especially those with advanced disease. In conclusion, pCCA is still hard to treat due to late diagnosis and extremely complicated surgical options. ELRAT also brings some hope, but it could be performed in very carefully selected patients. Advanced disease requires systemic anticancer treatment, which is supposed to be individualized according to the genetic and molecular features of cancer cells. Targeted therapy in combination with chemo-immunotherapy could be effective in susceptible patients.

Promising Highly Targeted Therapies for Cholangiocarcinoma: A Review and Future Perspectives

To overcome the poor prognosis of cholangiocarcinoma (CCA), highly targeted therapies, such as antibody-drug conjugates (ADCs), photodynamic therapy (PDT) with/without systemic chemotherapy, and experimental photoimmunotherapy (PIT), have been developed. Three preclinical trials have investigated the use of ADCs targeting specific antigens, namely HER2, MUC1, and glypican-1 (GPC1), for CCA. Trastuzumab emtansine demonstrated higher antiproliferative activity in CCA cells expressing higher levels of HER2. Similarly, "staphylococcal enterotoxin A-MUC1 antibody" and "anti-GPC1 antibody-monomethyl auristatin F" conjugates showed anticancer activity. PDT is effective in areas where appropriate photosensitizers and light coexist. Its mechanism involves photosensitizer excitation and subsequent reactive oxygen species production in cancer cells upon irradiation. Hematoporphyrin derivatives, temoporfin, phthalocyanine-4, talaporfin, and chlorine e6 derivatives have mainly been used clinically and preclinically in bile duct cancer. Currently, new forms of photosensitizers with nanotechnology and novel irradiation catheters are being developed. PIT is the most novel anti-cancer therapy developed in 2011 that selectively kills targeted cancer cells using a unique photosensitizer called "IR700" conjugated with an antibody specific for cancer cells. PIT is currently in the early stages of development for identifying appropriate CCA cell targets and irradiation devices. Future human and artificial intelligence collaboration has potential for overcoming challenges related to identifying universal CCA cell targets. This could pave the way for highly targeted therapies for CCA, such as ADC, PDT, and PIT.

Ado-tratuzumab emtansine beyond breast cancer: therapeutic role of targeting other HER2-positive cancers

Ado-trastuzumab emtansine (T-DM1) is an antibody-drug conjugate approved by the FDA in 2013 for advanced HER2-positive breast cancer treatment exhibiting promising clinical benefits. However, HER2 overexpression and gene amplification have also been reported in other cancers like gastric cancer, non-small cell lung cancer (NSCLC), and colorectal cancer. Numerous preclinical studies have also revealed the significant antitumor effect of T-DM1 on HER2-positive tumors. With the advancement in research, several clinical trials have been conducted to investigate the antitumor effect of T-DM1. In this review, we briefly introduced the pharmacological effects of T-DM1. We reviewed its preclinical and clinical studies, especially on other HER2-positive cancers, establishing what has been encountered between its preclinical and clinical studies. In clinical studies, we found that T-DM1 has a therapeutic value on other cancers. An insignificant effect was observed on gastric cancer and NSCLC, inconsistent with the preclinical studies.

Effectiveness of Trastuzumab Combined With Capecitabine Treatment in a Patient With Hilar Cholangiocarcinoma Complicated by Liver Metastases With an ERBB2-Activating Mutation: A Case Report

The identification of ERBB2 (HER2) alteration in some solid tumors has become critically important due to the actionable events predictive of response to anti-HER2 therapy. However, the efficacy of ERBB2 mutated hilar cholangiocarcinoma (hCCA) against ERBB2 is rarely reported. Here we report a 76-year-old female diagnosed with hCCA complicated by liver metastases after radical resection. The next-generation sequencing assay showed that the tumor had an ERBB2 mutation. Then, the patient was treated with trastuzumab plus capecitabine. After 2 months of treatment, she had a partial response. Until now, the patient is still alive. This study has shown the potential of trastuzumab combined with capecitabine as an effective treatment for hilar cholangiocarcinoma complicated by liver metastases harboring ERBB2 alterations.

Anti-Glypican-1 Antibody-drug Conjugate as Potential Therapy Against Tumor Cells and Tumor Vasculature for Glypican-1-Positive Cholangiocarcinoma

Cholangiocarcinoma is a highly malignant cancer. Many patients need systemic chemotherapy to prevent tumor development and recurrence; however, their prognosis is poor due to the lack of effective therapy. Therefore, a new treatment option is urgently required. We recently identified glypican-1 (GPC1) as a novel cancer antigen of esophageal squamous cell carcinoma. We also demonstrated the efficacy and safety of GPC1-targeted ADC (GPC1-ADC) conjugating anti-GPC1 mAb possessing high internalization activity with monomethyl auristatin F (MMAF), which is a potent tubulin polymerizing inhibitor. In this study, we confirmed that GPC1 was highly expressed in cholangiocarcinoma cells and tissues. IHC analysis of 49 extrahepatic cholangiocarcinoma patient tumor specimens revealed high expression of GPC1 in 47% of patients. These patients demonstrated significantly poorer prognosis compared with the low-expression group in terms of disease-free survival and overall survival (P < 0.05). GPC1 was also expressed in tumor vessels of cholangiocarcinoma, but not on the vessels of nontumor tissues. MMAF-conjugated GPC1-ADC showed potent tumor growth inhibition against GPC1-positive cholangiocarcinoma cells in vitro and in vivo In a GPC1 knockout xenograft model, GPC1-ADC partially inhibited tumor growth. Vascular endothelial cells in tumor tissues of GPC1-negative xenograft mice expressed GPC1 and were arrested in the G₂-M phase of cell cycle by GPC1-ADC. GPC1-ADC exhibits direct as well as indirect antitumor effects via inhibition of tumor angiogenesis. Our preclinical data highlight GPC1-ADC as a promising therapy for GPC1-positive cholangiocarcinoma.

Promising Molecular Targets for the Targeted Therapy of Biliary Tract Cancers: An Overview

Biliary tract cancer (BTC) is a leading cause of cancer-related death, due to the limited benefits of current systematic therapies and the heterogeneity of the tumor itself. High heterogeneity means that the clinical and molecular features vary between different subtypes of BTC, while the underlying molecular mechanisms remain unclear. Targeted therapy, where inhibitors are developed to selectively combine with targeted molecules in order to block abnormal signaling pathways in BTC, has shown promise as an emerging form of treatment for various types of cancer. In this article, a comprehensive review is conducted to examine potential molecular targets for BTC targeted therapy and their mechanisms. Furthermore, preliminary data published from clinical trials is utilized to analyze the main drugs used to combat BTC. The collective information presented in this article has provided useful insights into the current understanding of BTC.

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.

Combination efficacy of pertuzumab and trastuzumab for trastuzumab emtansine-resistant cells exhibiting attenuated lysosomal trafficking or efflux pumps upregulation

Purpose

Trastuzumab emtansine (T-DM1) is the standard treatment in the current second-line therapy of human epidermal growth factor receptor 2 (HER2)-positive metastatic breast cancer. However, a useful therapy after T-DM1 resistance has not been established. In this study, we established two different HER2-positive T-DM1-resistant cancer cells and evaluated the antitumor effect of trastuzumab in combination with pertuzumab (TRAS + PER).

Methods

Single-cell-cloned OE19 and BT-474 cells were cultured with increasing concentrations of T-DM1 to generate T-DM1-resistant OE19bTDR and BT-474bTDR cells, respectively. HER2 expression was assessed by immunohistochemistry. Multidrug resistance proteins (MDR1 and MRP1) were evaluated by real-time polymerase chain reaction and western blotting. Intracellular trafficking of T-DM1 was examined by flow cytometry and immunofluorescence staining. Efficacy of TRAS + PER was evaluated by cell proliferation assay, HER3 and AKT phosphorylation, caspase 3/7 activity, and antitumor activity.

Results

HER2 expression of both resistant cells was equivalent to that of the parent cells. Overexpression of MDR1 and MRP1 was observed and affected the T-DM1 sensitivity in the OE19bTDR cells. Abnormal localization of T-DM1 into the lysosomes was observed in the BT-474bTDR cells. In BT-474bTDR cells, TRAS + PER inhibited the phosphorylation of AKT involved in HER2–HER3 signaling, and apoptosis induction and cell proliferation inhibition were significantly higher with TRAS + PER than with the individual drugs. TRAS + PER significantly suppressed tumor growth in the OE19bTDR xenograft model compared with each single agent.

Conclusions

The results suggest that the TRAS + PER combination may be effective in T-DM1-resistant cancer cells where HER2 overexpression is maintained.

Electronic supplementary material

The online version of this article (10.1007/s00280-020-04138-5) contains supplementary material, which is available to authorized users.

Recent Progress in the Systemic Treatment of Advanced/Metastatic Cholangiocarcinoma

Cholangiocarcinomas (CCAs) comprise of a heterogeneous group of cancers arising in the biliary tract (intrahepatic or iCCA, perihilar or pCCA and distal or dCCA; the latter are known under the collective term of eCCA), each subtype having its own particularities in carcinogenesis, management and prognosis. The increasing incidence in recent decades, limited treatment options and high mortality rates, even in the early stages, have led to an imperious need for more in-depth understanding and development of tailored treatments for this type of aggressive tumour. The wide use of molecular profiling has increased the understanding of biology and identified key molecular drivers, for example, IDH1 mutations or FGFR2 fusions for iCCA, or BRAF mutations in eCCA. Most recently, the FDA approved pemigatinib, an FGFR inhibitor and ivosidenib, an IDH1 inhibitor, but even though progress has been made to better understand the mechanisms of tumorigenesis, genetic make-up, and tumour resistance to standard chemotherapy and targeted therapies, cholangiocarcinomas still represent an important challenge in the daily clinical practice of oncology. The purpose of this review is to highlight the recent progress in the systemic treatment of advanced/metastatic CCAs with a focus on targeted drugs and their biomarkers currently evaluated in early-phase clinical trials.

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.

Update on targeted cancer therapies, single or in combination, and their fine tuning for precision medicine

BACKGROUND

Until recently, patients who have the same type and stage of cancer all receive the same treatment. It has been established, however, that individuals with the same disease respond differently to the same therapy. Further, each tumor undergoes genetic changes that cause cancer to grow and metastasize. The changes that occur in one person's cancer may not occur in others with the same cancer type. These differences also lead to different responses to treatment. Precision medicine, also known as personalized medicine, is a strategy that allows the selection of a treatment based on the patient's genetic makeup. In the case of cancer, the treatment is tailored to take into account the genetic changes that may occur in an individual's tumor. Precision medicine, therefore, could be defined in terms of the targets involved in targeted therapy.

METHODS

A literature search in electronic data bases using keywords "cancer targeted therapy, personalized medicine and cancer combination therapies" was conducted to include papers from 2010 to June 2019.

RESULTS

Recent developments in strategies of targeted cancer therapy were reported. Specifically, on the two types of targeted therapy; first, immune-based therapy such as the use of immune checkpoint inhibitors (ICIs), immune cytokines, tumor-targeted superantigens (TTS) and ligand targeted therapeutics (LTTs). The second strategy deals with enzyme/small molecules-based therapies, such as the use of a proteolysis targeting chimera (PROTAC), antibody-drug conjugates (ADC) and antibody-directed enzyme prodrug therapy (ADEPT). The precise targeting of the drug to the gene or protein under attack was also investigated, in other words, how precision medicine can be used to tailor treatments.

CONCLUSION

The conventional therapeutic paradigm for cancer and other diseases has focused on a single type of intervention for all patients. However, a large literature in oncology supports the therapeutic benefits of a precision medicine approach to therapy as well as combination therapies.

Applied precision cancer medicine in metastatic biliary tract cancer

INTRODUCTION

Advanced therapy-refractory biliary tract cancer (BTC) has poor prognosis and constitutes a major challenge for adequate treatment strategies. By mapping the molecular profiles of advanced BTC patients, precision cancer medicine may provide targeted therapies for these patients.

OBJECTIVE

In this analysis, we aimed to show the potential of PCM in metastatic BTC.

METHODS

In this single-center, real-world retrospective analysis of our PCM platform, we describe the molecular profiling of 30 patients diagnosed with different types of metastatic BTC. Tumor samples of the patients were examined using a 161-gene next-generation sequencing panel, immunohistochemistry (IHC), and fluorescence in situ hybridization for chromosomal translocations.

RESULTS

In total, we identified 35 molecular aberrations in 30 patients. The predominant mutations were KRAS (n = 8), TP53 (n = 7), IDH2 (n = 4), and IDH1 (n = 3) that accounted for the majority of all molecular alterations (62.86%). BRAF mutations were observed in two patients. Less frequent alterations were noted in ARID1A, CTNNB1, ESR1, FBXW7, FGFR2, MET, NOTCH2, PIK3CA, PTCH1, SMAD4, and SRC1, each in one case. FGFR fusion gene was detected in one patient. No mutations were detected in eight patients. IHC revealed EGFR and p-mTOR expression in 28 patients. Applying these results to our patients, targeted therapy was recommended for 60% of the patients (n = 18). One patient achieved stable disease.

CONCLUSIONS

PCM is a feasible treatment approach and may provide molecular-guided therapy recommendations for metastatic BTC.

Pharmacotherapeutic options for biliary tract cancer: current standard of care and new perspectives

Introduction: Biliary tract cancer (BTC), which comprises gallbladder cancer, ampullary cancer, and cholangiocarcinoma, is a rare and heterogeneous entity, with limited approved therapeutic options. However, interest in this disease has grown exponentially in recent years, as a mounting body of evidence has shed light on the complex molecular and microenvironmental background of BTC, and clinical investigations have explored a variety of new agents and combinations, with promising results.Areas covered: This review describes the standard of care in advanced BTC and summarizes the most recent evidence available on the pharmacological treatment of resected and advanced disease, focusing on chemotherapy, targeted therapy, and immunotherapy.Expert opinion: The therapeutic armamentarium of BTC has made radical progress after almost a decade of very few positive results. Phase-III evidence now supports the use of adjuvant capecitabine after resection of localized disease, while investigations into improved regimens in the advanced setting are underway, exploring alternative options to the standard gemcitabine-cisplatin doublet. The first positive phase-III trial supports the use of the mFOLFOX6 regimen as a second-line chemotherapy. Targeted therapy against specific genomic alterations can combine with chemotherapy in specific subsets of patients. Despite recent advancements, conducting clinical trials for BTC is still a real challenge.

HER2-targeted therapies - a role beyond breast cancer

HER2 is an established therapeutic target in a large subset of women with breast cancer; a variety of agents including trastuzumab, pertuzumab, lapatinib, neratinib and trastuzumab emtansine (T-DM1) have been approved for the treatment of HER2-positive breast cancer. HER2 is also overexpressed in subsets of patients with other solid tumours. Notably, the addition of trastuzumab to first-line chemotherapy has improved the overall survival of patients with HER2-positive gastric cancer, and has become the standard-of-care treatment for this group of patients. However, trials involving pertuzumab, lapatinib and T-DM1 have failed to provide significant improvements in the outcomes of patients with HER2-positive gastric cancer. HER2-targeted therapies are also being tested in patients with other solid tumours harbouring HER2 overexpression, and/or amplifications or other mutations of the gene encoding HER2 (ERBB2), including biliary tract, colorectal, non-small-cell lung and bladder cancers. The experience with gastric cancer suggests that the successes observed in HER2-positive breast cancer might not be replicated in these other tumour types, owing to differences in the level of HER2 overexpression and other aspects of disease biology. In this Review, we describe the current role of HER2-targeted therapies beyond breast cancer and also highlight the potential of novel HER2-targeted agents that are currently in clinical development.