The force of HER2 - A druggable target in NSCLC?

Strategies for enhancing non-small cell lung cancer treatment: Integrating Chinese herbal medicines with epidermal growth factor receptor-tyrosine kinase inhibitors therapy

Non-small cell lung cancer (NSCLC) poses a global health threat, and epidermal growth factor receptor-tyrosine kinase inhibitors (EGFR-TKIs) such as gefitinib, afatinib, and osimertinib have achieved significant success in clinical treatment. However, the emergence of resistance limits the long-term efficacy of these treatments, necessitating urgent exploration of novel EGFR-TKIs. This review provides an in-depth summary and exploration of the resistance mechanisms associated with EGFR-TKIs, with a specific focus on representative drugs like gefitinib, afatinib, and osimertinib. Additionally, the review introduces a therapeutic strategy involving the combination of Chinese herbal medicines (CHMs) and chemotherapy drugs, highlighting the potential role of CHMs in overcoming NSCLC resistance. Through systematic analysis, we elucidate the primary resistance mechanisms of EGFR-TKIs in NSCLC treatment, emphasizing CHMs as potential treatment medicines and providing a fresh perspective for the development of next-generation EGFR-TKIs. This comprehensive review aims to guide the application of CHMs in combination therapy for NSCLC management, fostering the development of more effective and comprehensive treatment modalities to ultimately enhance patient outcomes.

Quantitative Measurement of HER2 Expression in Non-Small Cell Lung Cancer With a High-Sensitivity Assay

Recently, low human epidermal growth factor receptor 2 (HER2) protein expression has been proposed as a predictive biomarker for response to the antibody-drug conjugate trastuzumab deruxtecan (T-DXd) in metastatic breast cancer. HER2 expression in non-small cell lung cancer (NSCLC) patients has never been carefully measured, and little is known about the frequency of cases with unamplified but detectable levels of the protein. Although some HER2-targeted therapies have been studied in NSCLC patients, they have been restricted to those with genomic ERBB2 gene alterations, which only represent relatively rare cases of NSCLC. Still, emerging investigations of T-DXd in NSCLC have shown promise in patients with unamplified HER2. Taken together, we hypothesize that there may be many cases of NSCLC with levels of HER2 protein expression comparable with levels seen in breast cancer that benefit from T-DXd. Here, we used a previously validated, analytic, quantitative immunofluorescence (QIF) assay that is more sensitive than legacy clinical HER2 immunohistochemistry assays. We measured HER2 protein levels in NSCLC cases to determine the proportion of cases with detectable HER2 expression. Using cell line calibration microarrays alongside our QIF method enabled us to convert HER2 signal into units of attomoles per mm2. We found that over 63% of the 741 analyzed NSCLC cases exhibited HER2 expression above the limit of detection, with more than 17% of them exceeding the lower limit of quantification. Although the threshold for response to T-DXd in breast cancer is still unknown, many cases of NSCLC have expression in a range comparable to breast cancer cases with immunohistochemistry scores of 1+ or 2+. Our assay could potentially select NSCLC cases with a detectable target (ie, HER2) that might benefit from HER2 antibody-drug conjugates, irrespective of ERBB2 genomic alterations.

Immunohistochemistry of Lung Cancer Biomarkers

Immunohistochemical (IHC) staining represents a comparatively inexpensive testing method that is attractive as a potential alternative to molecular sequencing methods or fluorescence in situ hybridization for pulmonary biomarker testing. While a variety of IHC tests directed at actionable genetic alterations have been developed and evaluated since the advent of targeted therapy, specific antibody clones for anaplastic lymphoma kinase, ROS-1, and potentially neurotrophic tropmyosin receptor kinase have been the primary antibodies that provide sufficiently robust results to be utilized as either a primary testing or screening method to direct targeted therapy. Antibodies for a variety of other targets such as epidermal growth factor receptors, for example, have lacked sufficient sensitivity and specificity to cover the range of mutations that may occur and are generally not recommended in lieu of molecular testing with the exception of limited resource settings. IHC is also used as a predictive marker for response to immunotherapy through evaluation of programmed death ligand 1 expression. In addition, multiple antibody-drug conjugates (ADCs) are under investigation, designed to deliver drugs directly to tumor cells through binding to specific target antigens. Some ADCs have already received accelerated FDA approval, and IHC was incorporated in many clinical trials evaluating ADC efficacy. As such, it is anticipated that ADCs may have a companion diagnostic IHC to guide patient selection.

Enhanced anti-tumor effects by combination of tucatinib and radiation in HER2-overexpressing human cancer cell lines

BACKGROUND

Tucatinib (TUC), a HER2-directed tyrosine kinase inhibitor, is the first targeted drug demonstrating intracranial efficacy and significantly prolonged survival in metastatic HER2-positive breast cancer (BC) patients with brain metastases. Current treatments for brain metastases often include radiotherapy, but little is known about the effects of combination treatment with TUC. Therefore, we examined the combined effects of irradiation and TUC in human HER2-overexpressing BC, non-small cell lung cancer (NSCLC), and colorectal cancer (CRC) cell lines. For the latter two, a standard therapy successfully targeting HER2 is yet to be established.

METHODS

Nine HER2-overexpressing (BC: BT474, ZR7530, HCC1954; CRC: LS411N, DLD1, COLO201; NSCLC: DV90, NCI-H1781) and three control cell lines (BC: MCF7, HCC38; NSCLC: NCI-H2030) were examined. WST-1 assay (metabolic activity), BrdU ELISA (proliferation), γH2AX assay (DNA double-strand breaks (DSB), Annexin V assay (apoptosis), and clonogenic assay (clonogenicity) were performed after treatment with TUC and/or irradiation (IR). The relevance of the treatment sequence was analyzed exemplarily.

RESULTS

In BC, combinatorial treatment with TUC and IR significantly decreased metabolic activity, cell proliferation, clonogenicity and enhanced apoptotis compared to IR alone, whereby cell line-specific differences occurred. In the PI3KCA-mutated HCC1954 cell line, addition of alpelisib (ALP) further decreased clonogenicity. TUC delayed the repair of IR-induced DNA damage but did not induce DSB itself. Investigation of treatment sequence indicated a benefit of IR before TUC versus IR after TUC. Also in CRC and NSCLC, the combination led to a stronger inhibition of metabolic activity, proliferation, and clonogenic survival (only in NSCLC) than IR alone, whereby about 10-fold higher concentrations of TUC had to be applied than in BC to induce significant changes.

CONCLUSION

Our data indicate that combination of TUC and IR could be more effective than single treatment strategies for BC. Thereby, treatment sequence seems to be an important factor. The lower sensitivity to TUC in NSCLC and particularly in CRC (compared to BC) implicates, that tumor promotion there might be less HER2-related. Combination with inhibitors of other driver mutations may aid in overcoming partial TUC resistance. These findings are of high relevance to improve long-time prognosis especially in brain-metastasized situations given the intracranial activity of TUC.

Dacomitinib exhibits promising activity against the rare HER2 exon 20 insertion M774delinsWLV in lung cancer: A case report and literature review

A775_G776insYVMA, the typical and predominant HER2 exon 20 insertion variant in non-small cell lung cancer, exhibits relative insensitivity to covalent HER2-targeted tyrosine kinase inhibitors. However, other less common insertions have shown better responses to HER2-targeted inhibitors. M774delinsWLV is a rare HER2 exon 20 insertion subtype and its clinical sensitivity to HER2-targeted inhibitors remains unclear. Furthermore, there is a lack of current studies to elucidate its structure and predict its sensitivity to HER2-targeted tyrosine kinase inhibitors. Herein, we presented a case of non-small cell lung cancer harboring M774delinsWLV who derived favorable response and significant survival benefit from HER2-targeted tyrosine kinase inhibitors. A 60-year-old male with metastatic lung adenocarcinoma carrying M774delinsWLV received pyrotinib monotherapy as first-line treatment. After rapid disease progression at three months, sequential combination therapy with pyrotinib and bevacizumab yielded promising antitumor activity and sustained progression-free survival benefits for nearly a year. Subsequent dacomitinib monotherapy displayed significant activity against this uncommon insertion, resulting in a rapid decrease in tumor markers and partial response, along with progression-free survival of one year. The molecular simulation revealed no significant differences in the overall protein structure and binding pocket region between M774delinsWLV and the HER2 wild type. Drug binding dynamics simulation indicated that dacomitinib exhibited the most potent binding activity compared to afatinib, pyrotinib and poziotinib. Conclusively, dacomitinib exhibited promising efficacy against the rare HER2 exon 20 insertion M774delinsWLV. Extensive investigation is needed to elucidate the effects of HER2-targeted tyrosine kinase inhibitors on non-small cell lung cancer with different HER2 insertion subtypes.

Novel therapeutic strategies for rare mutations in non-small cell lung cancer

Lung cancer is still the leading cause of cancer-related mortality. Over the past two decades, the management of non-small cell lung cancer (NSCLC) has undergone a significant revolution. Since the first identification of activating mutations in the epidermal growth factor receptor (EGFR) gene in 2004, several genetic aberrations, such as anaplastic lymphoma kinase rearrangements (ALK), neurotrophic tropomyosin receptor kinase (NTRK) and hepatocyte growth factor receptor (MET), have been found. With the development of gene sequencing technology, the development of targeted drugs for rare mutations, such as multikinase inhibitors, has provided new strategies for treating lung cancer patients with rare mutations. Patients who harbor this type of oncologic driver might acquire a greater survival benefit from the use of targeted therapy than from the use of chemotherapy and immunotherapy. To date, more new agents and regimens can achieve satisfactory results in patients with NSCLC. In this review, we focus on recent advances and highlight the new approval of molecular targeted therapy for NSCLC patients with rare oncologic drivers.

Targeted therapeutic options in early and metastatic NSCLC-overview

The complex therapeutic strategy of non-small cell lung cancer (NSCLC) has changed significantly in recent years. Disease-free survival increased significantly with immunotherapy and chemotherapy registered in perioperative treatments, as well as adjuvant registered immunotherapy and targeted therapy (osimertinib) in case of EGFR mutation. In oncogenic-addictive metastatic NSCLC, primarily in adenocarcinoma, the range of targeted therapies is expanding, with which the expected overall survival increases significantly, measured in years. By 2021, the FDA and EMA have approved targeted agents to inhibit EGFR activating mutations, T790 M resistance mutation, BRAF V600E mutation, ALK, ROS1, NTRK and RET fusion. In 2022, the range of authorized target therapies was expanded. With therapies that inhibit KRASG12C, EGFR exon 20, HER2 and MET. Until now, there was no registered targeted therapy for the KRAS mutations, which affect 30% of adenocarcinomas. Thus, the greatest expectation surrounded the inhibition of the KRAS G12C mutation, which occurs in ∼15% of NSCLC, mainly in smokers and is characterized by a poor prognosis. Sotorasib and adagrasib are approved as second-line agents after at least one prior course of chemotherapy and/or immunotherapy. Adagrasib in first-line combination with pembrolizumab immunotherapy proved more beneficial, especially in patients with high expression of PD-L1. In EGFR exon 20 insertion mutation of lung adenocarcinoma, amivantanab was registered for progression after platinum-based chemotherapy. Lung adenocarcinoma carries an EGFR exon 20, HER2 insertion mutation in 2%, for which the first targeted therapy is trastuzumab deruxtecan, in patients already treated with platinum-based chemotherapy. Two orally administered selective c-MET inhibitors, capmatinib and tepotinib, were also approved after chemotherapy in adenocarcinoma carrying MET exon 14 skipping mutations of about 3%. Incorporating reflex testing with next-generation sequencing (NGS) expands personalized therapies by identifying guideline-recommended molecular alterations.

Drug conjugates for the treatment of lung cancer: from drug discovery to clinical practice

A drug conjugate consists of a cytotoxic drug bound via a linker to a targeted ligand, allowing the targeted delivery of the drug to one or more tumor sites. This approach simultaneously reduces drug toxicity and increases efficacy, with a powerful combination of efficient killing and precise targeting. Antibody‒drug conjugates (ADCs) are the best-known type of drug conjugate, combining the specificity of antibodies with the cytotoxicity of chemotherapeutic drugs to reduce adverse reactions by preferentially targeting the payload to the tumor. The structure of ADCs has also provided inspiration for the development of additional drug conjugates. In recent years, drug conjugates such as ADCs, peptide‒drug conjugates (PDCs) and radionuclide drug conjugates (RDCs) have been approved by the Food and Drug Administration (FDA). The scope and application of drug conjugates have been expanding, including combination therapy and precise drug delivery, and a variety of new conjugation technology concepts have emerged. Additionally, new conjugation technology-based drugs have been developed in industry. In addition to chemotherapy, targeted therapy and immunotherapy, drug conjugate therapy has undergone continuous development and made significant progress in treating lung cancer in recent years, offering a promising strategy for the treatment of this disease. In this review, we discuss recent advances in the use of drug conjugates for lung cancer treatment, including structure-based drug design, mechanisms of action, clinical trials, and side effects. Furthermore, challenges, potential approaches and future prospects are presented.

HER2 Alterations in Non-Small Cell Lung Cancer: Biologico-Clinical Consequences and Interest in Therapeutic Strategies

Lung cancer stands as the first cause of death by cancer in the world. Despite the improvement in patients' outcomes in the past decades through the development of personalized medicine approaches, a substantial portion of patients remains ineligible for targeted therapies due to the lack of a "druggable" molecular target. HER2, a receptor tyrosine kinase member of the EGFR/ErbB family, is known to show oncogenic properties. In this review, we focus on the different HER2 dysregulation mechanisms that have been observed in non-small cell lung cancer (NSCLC): gene mutation, gene amplification, protein overexpression and protein hyper-phosphorylation, the latter suggesting that HER2 dysregulation can occur independently of any molecular aberration. These HER2 alterations inevitably have consequences on tumor biology. Here, we discuss how they are not only involved in abnormal proliferation and survival of cancer cells but also potentially in increased angiogenic properties, mesenchymal features and tumor immune escape. Finally, we review the impact of these HER2 alterations in various therapeutic approaches. While standard chemotherapy and groundbreaking immunotherapy seem rather ineffective for HER2-altered NSCLCs, the development of HER2-targeted therapies such as tyrosine kinase inhibitors, anti-HER2 antibodies and especially antibody-drug conjugates could provide new hopes for patients.

Management of HER2 alterations in non-small cell lung cancer - The past, present, and future

HER2 mutations, which account for 2-4% of non-small cell lung cancer (NSCLC), are distinct molecular alterations identified via next generation sequencing (NGS). Previously, treatment outcomes in HER2-mutant metastatic NSCLC were dismal, showing limited clinical benefit with platinum-based chemotherapy with or without immunotherapy. In contrast to HER2-altered breast and gastric cancer, HER2-mutant NSCLC does not benefit from HER2 targeting agents such as trastuzumab or TDM1. HER2 mutations are also inherently different from HER2 overexpression and amplification. Currently, trastuzumab deruxtecan, a HER2 targeting antibody drug conjugate (ADC) is the first and only approved treatment option for patients with HER2-mutant metastatic NSCLC after failure with standard treatment. In this review, we summarized the biology of HER2 and detection of HER2 overexpression, amplification and mutations, as well as general landscape of landmark and ongoing clinical trials encompassing from chemotherapy to targeted agents, including tyrosine kinase inhibitors (TKIs), ADCs and investigational agents.

Liquid biopsy comprehensive genomic profiling of lung cancer in the Italian population: A real-world experience

OBJECTIVES

Liquid biopsy with next-generation sequencing (NGS) has emerged as a promising tool for tumor mutation profiling. In this study, we describe the genomic profile of Italian lung cancer patients tested with blood-based comprehensive genomic profiling (CGP) to assess the genomic landscape complexity and its impact on enhancing treatment options for patients.

MATERIALS AND METHODS

Between January 2021 and December 2021, a total of 229 lung cancer patients were profiled by FoundationOne®Liquid CDx (F1LCDx®) assay on circulating tumor DNA (ctDNA). F1LCDx® reports alterations across 324 cancer-related genes and genomic signatures, including tumor fraction (TF) and blood-based tumor mutational burden (bTMB). Detected variants were classified according to the ESMO Scale of Clinical Actionability for molecular Targets (ESCAT).

RESULTS

90.4% of patients had at least one detectable alteration in plasma. The most frequently mutated genes were TP53 (47.6%), DNMT3A (33.2%), EGFR (20.1%), and KRAS (15.7%). Elevated TF was detected in 18.3% of patients, suggesting high reliability of test results. According to the ESCAT classification, potentially actionable alterations (Tier I-II) were identified in 27.1% of samples. An additional 5.2% harbored an alteration for which an approved drug is available in other cancer types (Tier III). Furthermore, 13.1% of tumors exhibited high bTMB, which may predict response to immunotherapy. Overall, 156 (68.1%) patients were eligible for enrolment in clinical trials.

CONCLUSION

Liquid biopsy NGS is a viable and valuable approach to guide personalized therapy. The use of blood-based CGP may help identify a larger number of actionable mutations and increase chances of enrolment in clinical trials.

Exploration on the first-line treatment of ERBB2-altered advanced non-small cell lung cancer: A multicenter retrospective study

BACKGROUND

Although the treatment of ERBB2-altered non-small cell lung cancer (NSCLC) has been studied for many years, there are no comprehensive studies to evaluate the benefits of various therapies as first-line treatment. Through the development of immunotherapy, more and more different combination treatments were applicated in clinical practice, therefore, we conducted a multicenter retrospective study to evaluate the efficacy of different treatments.

METHODS

We enrolled patients with ERBB2-altered NSCLC who had undergone at least one-line systemic anticancer treatment to evaluate the efficacy of first-line chemotherapy alone (Chemo), anti-ERBB2 tyrosine kinase inhibitor (TKI), chemotherapy plus immunotherapy (Chemo + Immuno), chemotherapy plus anti-angiogenesis therapy (Chemo + Antiangio) and chemotherapy combined with immunotherapy and anti-angiogenesis therapy (Chemo + Immuno + Antiangio). The clinical outcomes included objective response rate (ORR), disease control rate (DCR), median progression-free survival (mPFS), one-year and three-year survival rate.

RESULTS

We enroll 36 patients harboring ERBB2 mutation and 29 with ERBB2 amplification. The overall ORR was 30.8%, DCR was 69.2% and mPFS was 5.7 months. Chemo + Immuno and Chemo + Antiangio both achieved longer mPFS than TKI (7.8 vs 3.6 months, HR: 0.24, 95 %CI: 0.09-0.64, P = 0.002; 5.9 vs 3.6 months, HR: 0.36, 95 %CI: 0.15-0.88, P = 0.019; respectively), while there was no significant difference in mPFS between Chemo + Immuno or Chemo + Antiangio and Chemo (both P > 0.05), the mPFS of the first two was longer. For ERBB2-mutant patients, the mPFS was 5.9 months, and Chemo + Immuno and Chemo + Antiangio both achieved longer mPFS than TKI (12.9 vs 2.9 months, HR: 0.15, 95 %CI: 0.03-0.68, P = 0.005; 7.1 vs 2.9 months, HR: 0.50, 95 %CI: 0.29-0.88, P = 0.009, respectively). In the same therapies, patients with ERBB2 mutation or ERBB2 amplification showed no statistical significance in PFS (both P > 0.05).

CONCLUSIONS

In the first-line treatment of ERBB2-altered NSCLC, chemotherapy combined with immunotherapy or anti-angiogenesis therapy may have greater survival benefits than ERBB2-target therapy, but the efficacy may not be better than that of chemotherapy.

Antibody-Drug Conjugates in Lung Cancer: Recent Advances and Implementing Strategies

Antibody-drug conjugates (ADCs) are one of the fastest-growing oncology therapeutics, merging the cytotoxic effect of conjugated payload with the high specific ability and selectivity of monoclonal antibody targeted on a specific cancer cell membrane antigen. The main targets for ADC development are antigens commonly expressed by lung cancer cells, but not in normal tissues. They include human epidermal growth factor receptor 2, human epidermal growth factor receptor 3, trophoblast cell surface antigen 2, c-MET, carcinoembryonic antigen-related cell adhesion molecule 5, and B7-H3, each with one or more specific ADCs that showed encouraging results in the lung cancer field, more in non-small-cell lung cancer than in small-cell lung cancer histology. To date, multiple ADCs are under evaluation, alone or in combination with different molecules (eg, chemotherapy agents or immune checkpoint inhibitors), and the optimal strategy for selecting patients who may benefit from the treatment is evolving, including an improvement of biomarker understanding, involving markers of resistance or response to the payload, besides the antibody target. In this review, we discuss the available evidence and future perspectives on ADCs for lung cancer treatment, including a comprehensive discussion on structure-based drug design, mechanism of action, and resistance concepts. Data were summarized by specific target antigen, biology, efficacy, and safety, differing among ADCs according to the ADC payload and their pharmacokinetics and pharmacodynamics properties.

Detailed curriculum vitae of HER2-targeted therapy

With the booming development of precision medicine, molecular targeted therapy has been widely used in clinical oncology treatment due to a smaller number of side effects and its superior accuracy compared to that of traditional strategies. Among them, human epidermal growth factor receptor 2 (HER2)-targeted therapy has attracted considerable attention and has been used in the clinical treatment of breast and gastric cancer. Despite excellent clinical effects, HER2-targeted therapy remains in its infancy due to its resulting inherent and acquired resistance. Here, a comprehensive overview of HER2 in numerous cancers is presented, including its biological role, involved signaling pathways, and the status of HER2-targeted therapy.

Novel HER2-Targeted Peptide for NIR-II Imaging of Tumor

Molecular targets serve a crucial role in drug development. Herein, we discovered a novel peptide that can specifically target the human epidermal growth factor receptor 2 (HER2) and thus named it Herceptide. In our study, Herceptide was conjugated to the near-infrared fluorescent dye indocyanine green (ICG) to obtain a probe, ICG-Herceptide. Importantly, specific binding to HER2 was revealed by molecular docking, surface plasmon resonance analysis, and competition assays. The probe showed high binding affinity (K_D = 1.03 nM) and fast binding property (k_on = 0.44 min^-1). In vivo near-infrared window two (NIR-II, 1000-1700 nm) imaging in HER2-overexpressed SKOV3 tumor-bearing mice demonstrated a high tumor-to-normal tissue signal ratio (T/N = 7.3) at 8 h postinjection. In the blocking study, ICG-Herceptide coinjected with Herceptide only showed a weak tumor signal. In other HER2 high-expression tumors, such as non-small-cell lung cancer A549 and gastric cancer MKN45, the tumor-to-normal tissue signal ratios (T/N) were 4.1 and 4.7, respectively. In contrast, HER2 low-expression tumor MDAMB231 shows no imaging contrast between the tumor and normal tissues. Furthermore, tumor resection was successfully performed under the guidance of the ICG-Herceptide-based NIR-II imaging in subcutaneous SKOV3 mice models. The biocompatibility study indicated that the probe had no observable toxicity to cells and tissues. Overall, these results demonstrate that ICG-Herceptide is a promising optical probe for the diagnosis and localization of HER2-overexpressing tumors. Moreover, Herceptide is a novel HER2-targeting peptide and can be further used for developing theranostic agents.

Mutant forms of EGFR promote HER2 trafficking through efficient formation of HER2-EGFR heterodimers

INTRODUCTION

Human epidermal growth factor receptor 2 (HER2) forms homodimers and is retained at the surface of cancer cells positive for HER2 amplification. The dimerization, internalization, and intracellular trafficking of HER2 in cancer cells without HER2 amplification have remained uncharacterized, however.

MATERIALS AND METHODS

HER2 homodimers and heterodimers were detected in various cell lines with the use of an in situ proximity ligation assay. The effects of wild-type or mutant forms of epidermal growth factor receptor (EGFR) on intracellular trafficking of HER2 were examined by live-cell imaging. The sensitivity of cell lines without HER2 amplification to ado-trastuzumab emtansine (T-DM1), an anti-HER2 (trastuzumab)-cytotoxic drug conjugate (ADC) was also investigated.

RESULTS

HER2 preferentially formed heterodimers with EGFR rather than homodimers and was rapidly internalized together with EGFR in cells without HER2 amplification. HER2-EGFR heterodimers were more abundant and HER2 was more efficiently transferred to lysosomes in such cells with than in those without EGFR activating mutations. T-DM1 showed a high cytotoxic efficacy in the cells with EGFR mutations, suggesting that mutant forms of EGFR promote the transfer of HER2-bound T-DM1 to lysosomes through efficient formation of HER2-EGFR heterodimers.

CONCLUSION

Our findings reveal that HER2 trafficking is affected by EGFR, especially by mutant forms of the receptor, and they provide a rationale for the use of HER2-targeting ADCs in the treatment of EGFR-mutated lung cancer.

Chinese expert consensus on the diagnosis and treatment of HER2-altered non-small cell lung cancer

Human epidermal growth factor receptor 2 (HER2) possesses tyrosine kinase activity and participates in cell growth, differentiation and migration, and survival. Its alterations, mainly including mutations, amplifications, and overexpression are associated with poor prognosis and are one of the major drivers in non-small cell lung cancer (NSCLC). Several clinical trials had been investigating on the treatments of HER2-altered NSCLC, including conventional chemotherapy, programmed death 1 (PD-1) inhibitors, tyrosine kinase inhibitors (TKIs) and antibody-drug conjugates (ADCs), however, the results were either disappointing or encouraging, but inconsistent. Trastuzumab deruxtecan (T-DXd) was recently approved by the Food and Drug Administration as the first targeted agent for treating HER2-mutant NSCLC. Effective screening of patients is the key to the clinical application of HER2-targeted agents such as TKIs and ADCs. Various testing methods are nowadays available, including polymerase chain reaction (PCR), next-generation sequencing (NGS), fluorescence in situ hybridization (FISH), immunohistochemistry (IHC), etc. Each method has its pros and cons and should be reasonably assigned to appropriate patients for diagnosis and guiding treatment decisions. To help standardize the clinical workflow, our expert group reached a consensus on the clinical management of HER2-altered NSCLC, focusing on the diagnosis and treatment strategies.

HER2 in Non-Small Cell Lung Cancer: A Review of Emerging Therapies

Simple Summary

There are growing data on targeting HER2 alterations, which include gene mutations, gene amplifications, and protein overexpression, for non-small cell lung cancer (NSCLC). Currently, there are limited targeted therapies approved for NSCLC patients with HER2 alterations, and this remains an unmet clinical need. There has been an influx of research on antibody–drug conjugates, monoclonal antibodies, and tyrosine kinase inhibitors. This review discusses the diagnostic challenges of HER2 alterations in NSCLC and summarizes recent progress in HER2 targeted drugs for both clinicians and researchers treating this patient population.

Abstract

Human epidermal growth factor receptor 2 (HER2), a member of the ERBB family of tyrosine kinase receptors, has emerged as a therapeutic target of interest for non-small cell lung cancer (NSCLC) in recent years. Activating HER2 alterations in NSCLC include gene mutations, gene amplifications, and protein overexpression. In particular, the HER2 exon 20 mutation is now a well clinically validated biomarker. Currently, there are limited targeted therapies approved for NSCLC patients with HER2 alterations. This remains an unmet clinical need, as HER2 alterations are present in 7–27% of de novo NSCLC and may serve as a resistance mechanism in up to 10% of EGFR mutated NSCLC. There has been an influx of research on antibody–drug conjugates (ADCs), monoclonal antibodies, and tyrosine kinase inhibitors (TKIs) with mixed results. The most promising therapies are ADCs (trastuzumab-deruxtecan) and novel TKIs targeting exon 20 mutations (poziotinib, mobocertinib and pyrotinib); both have resulted in meaningful anti-tumor efficacy in HER2 mutated NSCLC. Future studies on HER2 targeted therapy will need to define the specific HER2 alteration to better select patients who will benefit, particularly for HER2 amplification and overexpression. Given the variety of HER2 targeted drugs, sequencing of these agents and optimizing combination therapies will depend on more mature efficacy data from clinical trials and toxicity profiles. This review highlights the challenges of diagnosing HER2 alterations, summarizes recent progress in novel HER2-targeted agents, and projects next steps in advancing treatment for the thousands of patients with HER2 altered NSCLC.

Advanced non-small-cell lung cancer: how to manage EGFR and HER2 exon 20 insertion mutation-positive disease

EGFR exon 20 insertion mutations (Ex20ins) and HER2 mutations characterize an oncogene-addicted subtype of non-small-cell lung cancer (NSCLC) typically associated with a never or light smoking history, female sex, and adenocarcinoma histology. Nevertheless, Ex20ins-mutant and HER2-mutant advanced NSCLCs are still difficult to treat for various reasons. First, there is a need for sophisticated diagnostic tools (e.g. next-generation sequencing) that could allow the identification of these relatively rare molecular drivers. Second, highly active targeted drugs that might support a significant change in patients' prognosis when used as first-line therapy are required. In fact, although a few targeted drugs have so far demonstrated antitumour activity for these patients, mainly selective human epidermal receptor-tyrosine kinase inhibitors such as poziotinib and mobocertinib (for both molecular alterations), monoclonal antibodies such as amivantamab (for Ex20ins), and antibody-drug conjugates such as trastuzumab deruxtecan (for HER2 mutants), they are mostly confined for clinical use in pretreated patients. Finally, Ex20ins-targeted or HER2-targeted drugs might be difficult to access in different countries or regions worldwide. In the present review, we provide a concise but comprehensive summary of the challenges that lie ahead as we move towards personalized treatment of Ex20ins-mutant and HER2-mutant advanced NSCLC, also suggesting a treatment algorithm that could be followed for patients with these genetic aberrations.

Trastuzumab and pertuzumab combination therapy for advanced pre-treated HER2 exon 20-mutated non-small cell lung cancer

INTRODUCTION

In 1-3% of non-small cell lung cancer (NSCLC) human epidermal growth factor 2 (HER2) mutations are identified as a genomic driver. Nevertheless, no HER2-targeted treatment is approved for NSCLC. In the Drug Rediscovery Protocol (DRUP), patients are treated with off-label drugs based on their molecular profile. Here, we present the results of the cohort 'trastuzumab/pertuzumab for HER2 exon20 mutation positive (HER2m+) NSCLC'.

METHODS

Patients with treatment refractory, advanced HER2m+ NSCLC with measurable disease (RECISTv1.1) were eligible. Treatment with intravenous trastuzumab combined with pertuzumab every 3 weeks was administered. The primary end-point was clinical benefit (CB: either objective response or stable disease ≥ 16 weeks). Patients were enrolled using a Simon-like 2-stage design, with 8 patients in stage 1 and up to 24 patients in stage 2 if at least 1 patient had CB in stage 1. At baseline, a biopsy for biomarker analysis, including whole genome sequencing, was obtained.

RESULTS

Twenty-four evaluable patients were enrolled and treated between May 2017 and August 2020. CB was observed in 9 patients (38%); including an objective response rate of 8.3% (2 patients had a partial response) and 7 patients with stable disease ≥ 16 weeks. The most frequently observed HER2 mutation was p.Y772_A775dup (71%, n = 20). Median follow-up was 13 months, median progression-free survival and overall survival 4 (95% CI 3-6) and 10 months (95% CI 4 - not reached), respectively. Whole genome sequencing data (available for 67% of patients) confirmed the inclusion mutation in all cases. No unexpected toxicity was observed.

CONCLUSION

Despite the fact that the study did meet its primary end-point, trastuzumab/pertuzumab was only marginally active in a subset of patients with heavily pre-treated HER2m+ NSCLC.

[Targeted Therapy and Mechanism of Drug Resistance in Non-small Cell Lung Cancer with Epidermal Growth Factor Receptor Gene Mutation]

Lung cancer is the sixth leading cause of death worldwide and one of the leading cause of death from malignant tumors. Non-small cell lung cancer (NSCLC) is the most common type of lung cancer. Epidermal growth factor receptor (EGFR) gene mutation is a common mutation in NSCLC. For advanced NSCLC patients with EGFR mutations, EGFR-tyrosine kinase inhibitors (EGFR-TKIs), such as Gefitinib, Afatinib, Oxitinib and other targeted therapies have become the first-line treatment recommended by many guidelines, but many patients develop acquired drug resistance after about 1 year of medication. Patients with drug resistance will have earlier disease progression than patients without drug resistance, which has an important impact on the prognosis of patients. At present, the main treatment for patients with acquired resistance is new target inhibition for resistant mutation. For example, if patients with T790M mutation are resistant to the first or second generation drugs such as Gefitinb and Afatinib, they can be treated with the third generation drugs (Osimertinib or Almonertinib), which can delay the progression of the disease. Therefore, the study of drug resistance mechanism and treatment of drug resistance patients are essential. This paper mainly reviews targeted therapy and drug resistance mechanism of EGFR-mutant NSCLC patients, in order to provide reference for clinical application of EGFR-TKIs.
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Multiplex Droplet Digital PCR Assay for Detection of MET and HER2 Genes Amplification in Non-Small Cell Lung Cancer

Non-small-cell lung cancer (NSCLC), a subtype of lung cancer, remains one of the most common tumors with a high mortality and morbidity rate. Numerous targeted drugs were implemented or are now developed for the treatment of NSCLC. Two genes, HER2 and MET, are among targets for these specific therapeutic agents. Alterations in HER2 and MET could lead to primary or acquired resistance to commonly used anti-EGFR drugs. Using current methods for detecting HER2 and MET amplifications is time and labor-consuming; alternative methods are required for HER2 and MET testing. We developed the first multiplex droplet digital PCR assay for the simultaneous detection of MET and HER2 amplification in NSCLC samples. The suitability of qPCR was assessed for the optimization of multiplex ddPCR. The optimal elongation temperature, reference genes for DNA quantification, and amplicon length were selected. The developed ddPCR was validated on control samples with various DNA concentrations and ratios of MET and HER2 genes. Using ddPCR, 436 EGFR-negative NSCLC samples were analyzed. Among the tested samples, five specimens (1.15%) showed a higher ratio of MET, and six samples (1.38%) showed a higher ratio of HER2. The reported multiplex ddPCR assay could be used for the routine screening of MET and HER2 amplification in NSCLC samples.

Specific HER2 Exon 20 Gly776 Deletion-Insertions in Non-Small Cell Lung Cancer: Structural Analysis and Sensitivity to HER2-Targeted Tyrosine Kinase Inhibitors

Background: HER2 exon 20 insertions remain a subset heterogeneous alterations in lung cancer, with currently unmet need for precision targeted therapy. G776delinsVC, a typical HER2 exon 20 deletion-insertion at codon Gly776, was reported to respond discrepantly to afatinib compared with the predominant insertion A775_G776insYVMA (YVMA). However, it lacks structural evidence to illustrate the possible mechanism and predict the binding activities of its similar variants over YVMA insertion to HER2-targered tyrosine kinase inhibitors (TKIs). Methods: Real-world cohort study was performed to investigate clinical outcomes with HER2-targeted TKI afatinib and pyrotinib, and structural analysis for exon 20 Gly776 deletion-insertions G776delinsVC, G776delinsLC and G776delinsVV, and YVMA by molecular dynamics simulation and cellular kinase inhibition assay were provided for full exploration. Results: Afatinib revealed low objective response rate (ORR) of 0-9.5% and short median progression-free survival (mPFS) of 2.8-3.2 months for YVMA, but with higher ORR of 20-28.6% and longer mPFS of 4.3-7.1 months for G776delinsVC. Pyrotinib presented significantly improved PFS benefit than afatinib for G776delinsVC and YVMA as first-line (median, 6.8 vs. 3.4 months, p = 0.010) or second-line therapy (median, 5.8 vs. 2.8 months, p < 0.001). No significant difference was observed on drug binding pocket and TKI binding activity between G776delinsVC, G776delinsLC and G776delinsVV, and both afatinib and pyrotinib showed favorable binding activity. YVMA insertion significantly affected the loop region with altering HER2 protein secondary structure and forming steric hindrance to binding of afatinib. Pyrotinib showed the best selectivity to HER2, with more favorable activity to YVMA than afatinib indicated by cellular inhibition assay. Conclusion: Both afatinib and pyrotinib showed favorable activity for NSCLC patients with HER2 exon 20 Gly776 deletion-insertions. Pyrotinib revealed more potent activity to A775_G776insYVMA insertion than afatinib due to the steric binding hindrance induced by YVMA.

Clinical Characteristics and Prognosis of HER2 Gene Phenotype in Patients with Non-Small Cell Lung Cancer

Introduction

We aim to investigate the relationship between HER2 gene phenotype and clinical characteristics, distribution and prognosis of non-small cell lung cancer (NSCLC) patients.

Methods

A total of 249 NSCLC patients admitted to the oncology department of our hospital from January 2015 to January 2018 were retrospectively analyzed. The clinicopathological information, CT signs, clinical efficacy and long-term prognosis were collected and compared.

Results

A total of 249 NSCLC patients underwent HER2 gene testing, 21 of them (8.43%) complied with HER2 alterations [HER2 (+)], and there were significant differences in tumor stages among patients with different HER2 phenotypes (P<0.05). Among 21 NSCLC patients with HER2 (+), HER2 gene mutation was found in 17 patients (81%), and HER2 gene amplification in 4 patients (19%). Among the HER2 mutations, 12 cases (57%) were 20 exon mutations, and 5 cases (19%) were other mutations. Analysis of CT signs showed that border lobulation/burr, necrosis sign and pleural depression were correlated with HER2 gene mutation (P<0.05). The incidence of EGRF mutation in HER (+) patients was significantly lower than that in HER (-) patients (P<0.05), but there was no significant difference in the incidence of ALK gene mutation among different HER phenotypes (P>0.05). The disease control rate of HER2 (+) patients was significantly lower than that of HER2 (-) patients, and the 12-month progression-free survival rate and survival rate of HER2 (+) patients were significantly higher than those of HER2 (-) patients (P<0.05). There was no significant difference in the incidence of ADR among HER2 patients with different phenotypes, but the incidence of ADR (adverse drug reaction) in HER2 (+) patients with Grade 3 or 4 was significantly higher than that in the control group (P<0.05).

Discussion

The incidence of HER2 gene mutations in NSCLC patients is relatively low, but it is far commoner in patients with stage IIIB~IV, among which exon 20 mutations are the most prevalent. In CT signs, the lesion lobulated sign/spiculated sign, necrosis signs, and pleural depression signs are related to HER2 gene mutations. In addition, HER2 gene mutations play a crucial role in the clinical prognosis and treatment safety of patients.

Pyrotinib in HER2 heterogeneously mutated or amplified advanced non-small cell lung cancer patients: a retrospective real-world study (PEARL)

Human epidermal growth factor receptor 2 (HER2) amplification or activating mutations are found in 1.6%-4% of non-small cell lung cancer (NSCLC). Pyrotinib has been reported to have better potency in NSCLC patients with HER2 exon 20 insertion (ex20ins) mutations; however, more clinical evidence is urgently needed to guide pyrotinib-based therapy in NSCLC with HER2 amplification or heterogeneous mutations. We retrospectively analyzed advanced NSCLC patients with HER2 amplification or mutations who were treated with pyrotinib-based therapy between September 25, 2018 and October 30, 2020 in our hospital. Molecular dynamics simulation was used to explore the bioactive conformation and binding mechanisms of pan-ErbB tyrosine kinase inhibitors (TKIs) including pyrotinib for different HER2 ex20ins variants. In this study, 79 eligible patients were included with 70 ex20ins variants, 6 missense mutations and 3 primary HER2 amplifications identified. A775_G776insYVMA insertion was the most common observed subtype. The median progression-free survival (mPFS) was 5.8 (95% CI: 4.1-7.4) months. Use of pyrotinib-based therapy in first-/second-line settings showed a significantly better prognosis than that observed in third-line settings or above (mPFS: 9.1 vs. 4.4 months; P = 0.0003). Compared with HER2 amplification and exon 20 non-YVMA insertion variants, patients with HER2 missense mutations had a visible mPFS benefit (12.2 vs. 6.8 vs. 5.2 months). Computational docking simulations revealed that pyrotinib failed to interact with the specific insertion variant P780_Y781insGSP. These results indicated that pyrotinib-based therapy exhibited good anti-tumor activity and acceptable safety profile in HER2-altered advanced NSCLC.

Afatinib combined with anlotinib in the treatment of lung adenocarcinoma patient with novel HER2 mutation: a case report and review of the literature

Background

HER2 is a member of the ERBB family of receptor tyrosine kinases, and HER2 mutations occur in 1–4% of non-small cell lung cancer (NSCLC) as an oncogenic driver mutation. We found a rare mutation of HER2 p.Asp769Tyr in NSCLC.

Case presentation

We presented a case of a 68-year-old nonsmoking male patient with brain metastasis from lung adenocarcinoma harboring a rare mutation of HER2 p.Asp769Tyr. After multiple lines of treatment, he obtained a durable response (10 months) to afatinib and anlotinib.

Conclusion

We reported for the first time that afatinib and anlotinib have successfully treated lung adenocarcinoma with HER2 p.Asp769Tyr mutation. This finding can provide an insight into the optimal treatment of lung adenocarcinoma patients with novel mutations. Additionally, we summarized the efficacy of targeted therapy for HER2 mutant lung cancer in this article.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12957-021-02444-7.

Pyrotinib in Patients with HER2-Amplified Advanced Non-Small Cell Lung Cancer: A Prospective, Multicenter, Single-Arm Trial

PURPOSE

In this study, we aimed to evaluate the efficacy and safety of pyrotinib, a pan-HER inhibitor, in HER2-amplified NSCLC patients.

PATIENTS AND METHODS

In this prospective, multicenter, single-arm trial (ChiCTR1800020262), advanced NSCLC patients with HER2 amplification, as determined by next-generation sequencing, were enrolled and administered pyrotinib orally at 400 mg per day. The primary endpoint was 6-month progression-free survival (PFS) rate. Other endpoints included objective response rate (ORR), disease control rate (DCR), PFS, overall survival (OS), and safety.

RESULTS

The enrolled cohort included twenty-seven patients with HER2 amplification. The 6-month PFS rate was 51.9% (95% confidence interval [CI] 34.0%-69.3%). The median PFS was 6.3 months (95%CI 3.0-9.6 months), and median OS was 12.5 months (95%CI 8.2-16.8 months). Pyrotinib elicited a confirmed ORR of 22.2% (95%CI 10.6%-40.8%). Patients administered pyrotinib as first-line treatment achieved an mPFS of 12.4 months. Moreover, 30.8% of the patients who had progressed on epidermal growth factor receptor (EGFR) tyrosine kinase inhibitor (TKI) responded to pyrotinib. Patients with brain metastases had an ORR of 40%. Treatment-related adverse events (TRAEs) occurred in all patients (grade 3, 22.2%), but no grade 4 or higher TRAEs were documented. Diarrhea was the most frequent TRAE (all, 92.6%; grade 3, 7.4%). Loss of HER2 amplification was detected upon disease progression.

CONCLUSIONS

Pyrotinib provided antitumor efficacy with a manageable safety profile in HER2-amplified NSCLC patients.

Update on molecular pathology and role of liquid biopsy in nonsmall cell lung cancer

Personalised medicine, an essential component of modern thoracic oncology, has been evolving continuously ever since the discovery of the epidermal growth factor receptor and its tyrosine kinase inhibitors. Today, screening for driver alterations in patients with advanced lung adenocarcinoma as well as those with squamous cell carcinoma and no/little history of smoking is mandatory. Multiplex molecular platforms are preferred to sequential molecular testing since they are less time- and tissue-consuming. In this review, we present the latest updates on the nine most common actionable driver alterations in nonsmall cell lung cancer. Liquid biopsy, a simple noninvasive technique that uses different analytes, mostly circulating tumour DNA, is an appealing tool that is used in thoracic oncology to identify driver alterations including resistance mutations. Additional roles are being evaluated in clinical trials and include monitoring the response to treatment, screening for lung cancer in high-risk patients and early detection of relapse in the adjuvant setting. In addition, liquid biopsy is being tested in immune-oncology as a prognostic, predictive and pharmacodynamic tool. The major limitation of plasma-based assays remains their low sensitivity when compared to tissue-based assays. Ensuring the clinical validity and utility of liquid biopsy will definitely optimise cancer care.

The Value of Population Screening in Advancing Personalized Medicine in the Field of Lung Cancer

During the past decade, progress has been made in the field of lung cancer molecular biology and onco-immunology, leading to prolonged survival of patients. The combination of increased fundamental knowledge and the pharmaceutical pipeline has allowed the development of various tyrosine kinase inhibitors, targeting numerous molecular alterations. These drugs are now available in daily practice and have transformed survival outcomes for patients harboring EGFR, ALK or ROS1 alterations. Multiple clinical trials are now ongoing in order to increase the number of approved drugs, thus overcoming the issues of rare mutations and tyrosine kinase inhibitors resistance. Immune checkpoint inhibitors development has also changed lung cancer outcomes, but underwhelming response rates highlight the need for immune biomarkers. While PD-L1 expression was the first approved immune biomarker, it has shown several limitations and new biomarkers have to be identified to predict response or resistance to immune checkpoint inhibitors. Testing methods, molecular results and targeted therapeutic schedules will be harmonized in the coming years, with the help of dedicated molecular multidisciplinary boards.

Clinicopathologic features and treatment advances in cancers with HER2 alterations

HER2 is one of the most important proteins of the epidermal growth factor receptor (EGFR) family, whose alterations include amplification, overexpression and gene mutation. Growing attention has been given to HER2 as a biomarker for prognosis, an indicator for treatment response and a target for new drugs. Tumors with HER2 alterations have been well studied in multiple locations as distinct entities for treatment, especially breast cancer, gastric cancer, lung cancer and colorectal cancer. These four cancers are the leading causes of cancer incidence and cancer-related death worldwide. The present study details the landscape of HER2 amplification/overexpression and mutations and gives an up-to-date analysis of current clinical trials in the four cancers mentioned above. Different HER2-altered cancers not only respond differently to HER2-targeting therapies but also display diverse survival outcomes. Even in the same type of cancer, HER2 amplification/overexpression differs from HER2 mutation in terms of clinicopathologic features and treatment strategies. As an emerging strategy in cancer treatment, immune checkpoint inhibitors demonstrate distinct outcomes in HER2-altered breast cancer, gastric cancer and lung cancer.

Cytogenetic and Biochemical Genetic Techniques for Personalized Drug Therapy in Europe

For many authorized drugs, accumulating scientific evidence supports testing for predictive biomarkers to apply personalized therapy and support preventive measures regarding adverse drug reactions and treatment failure. Here, we review cytogenetic and biochemical genetic testing methods that are available to guide therapy with drugs centrally approved in the European Union (EU). We identified several methods and combinations of techniques registered in the Genetic Testing Registry (GTR), which can be used to guide therapy with drugs for which pharmacogenomic-related information is provided in the European public assessment reports. Although this registry provides information on genetic tests offered worldwide, we identified limitations regarding standard techniques applied in clinical practice and the information on test validity rarely provided in the according sections.

The rapidly evolving landscape of novel targeted therapies in advanced non-small cell lung cancer

Lung cancer is a highly heterogeneous disease often driven by well-characterized driver mutations. Although the best studied are common alterations in the epidermal growth factor receptor (EGFR) and anaplastic lymphoma kinase (ALK) oncogenes, rapid advances in molecular characterization has led to the development of novel therapeutics that inhibit additional oncogenic alterations in advanced NSCLC. The literature search identified 62 eligible phase I/II clinical trials or integrated analyses of assessing novel targeted agents against the following molecular alterations: ROS1-rearranged, BRAF V600E-mutant, NTRK-rearranged, MET-altered, uncommon EGFR-mutant, RET-rearranged, HER2-positive, KRAS G12C-mutant and NRG1-rearranged. This rapidly evolving field has produced many new targeted treatment options and promising outcomes have led to the FDA approval of seven novel agents for use in ROS1-rearranged, BRAF V600E-mutant, NTRK-rearranged, MET exon 14 skipping-mutant or RET-rearranged advanced NSCLC. Research continues at a rapid pace, with a number of phase III trials underway to fully evaluate new promising agents under development for improving outcomes in patients with NSCLC harboring distinct molecular subtypes. This review will provide a comprehensive summary of existing data as well as a user-friendly guide on the current status of novel targeted therapy in oncogene-driven advanced NSCLC.

Druggable targets meet oncogenic drivers: opportunities and limitations of target-based classification of tumors and the role of Molecular Tumor Boards

The therapeutic landscape of cancer is changing rapidly due to the growing number of approved drugs capable of targeting specific genetic alterations. This aspect, together with the development of noninvasive methods for the assessment of somatic mutations in the peripheral blood of patients, generated a growing interest toward a new tumor-agnostic classification system based on ‘predictive’ biomarkers. The current review article discusses this emerging alternative approach to the classification of cancer and its implications for the selection of treatments. It is suggested that different types of cancers sharing the same molecular profiles could benefit from the same targeted drugs. Although recent clinical trials have demonstrated that this approach cannot be generalized, there are also specific examples that demonstrate the clinical utility of this alternative vision. In this rapidly evolving scenario, a multidisciplinary approach managed by institutional Molecular Tumor Boards is fundamental to interpret the biological and clinical relevance of genetic alterations and the complexity of their relationship with treatment response.

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The identification of oncogenic drivers offers the opportunity to develop target-specific drugs.

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The inhibition of crucial pathways realizes the principle of druggable target to exploit cancer vulnerability.

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The approval of new anticancer agents based on target-based concept represents a paradigm shift in cancer therapy.

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However, only few drugs have been approved so far on an agnostic basis and the concept of biomarker cannot be generalized.

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Tumor Molecular Boards will have an increasing role in the identification of new therapeutic options in selected patients.

Targeting HER2 expression in cancer: New drugs and new indications

Functional activation of human epidermal growth factor receptor 2 (HER2) has been shown to strongly promote carcinogenesis, leading to the investigation of HER2-directed agents in cancers with HER2 genomic alterations. This has been best documented in the context of HER2 gene amplification in breast and gastric/gastroesophageal junction carcinomas for which several HER2-directed agents are available and have become a part of standard treatment regimens. Somatic HER2 gene mutations have been recently described at low frequency in a variety of human cancers and have emerged as a novel predictive biomarker for HER2-directed therapies. Preclinical data also indicate that activating HER2 mutations are potent oncogenic drivers in a manner that is analogous to HER2 amplification. HER2 mutations may clinically confer sensitivity to HER2-directed agents as recently shown in a phase II clinical trial with antibody-drug conjugate against HER2 trastuzumab deruxtecan in patients with non-squamous non-small cell lung carcinoma.

Diagnostic and therapeutic ERβ, HER2, BRCA biomakers in the histological subtypes of lung adenocarcinoma according to the IASLC/ATS/ERS classification

Several studies revealed that non-small cell lung cancers (NSCLCs) frequently express ER, PR, HER2 and carry BRCA mutation. However, these markers in histological subtypes of lung adenocarcinoma have not been thoroughly investigated. We retrospectively evaluated a total of 640 lung adenocarcinoma samples for ERα, ERβ, PR and HER2 expression by immunohistochemistry and western-blotting, for EGFR and BRCA mutation by real-time PCR and sequencing. Furthermore, HER2 amplification and mutation were explored in samples harboring immunopositivity HER2 using fluorescence in situ hybridization and real-time PCR, respectively. The micropapillary and invasive mucinous predominant adenocarcinoma were frequently detected the higher level of cytoplasmic ERβ (64.9% and 56.6%), HER2 (68.1% and 60.1%) protein expression. But, amplification of HER2 was detected in only three cases (3/110, 2.7%) and 26 HER2 mutations in 110 cases were identified (23.6%) in the HER2 immunopositivity patients. Logistic regression analysis showed that cytoplasmic ERβ (P = 0.032) and HER2 (P = 0.015) expression were independently associated with EGFR mutation. 8 patients (8/640, 1.25%) harbored pathogenic BRCA mutations, 6 with germline BRCA mutations and 2 with somatic BRCA1 mutations were detected with lacking ERβ, PR and HER2 expression. Acinar predominant adenocarcinoma had the higher percentage of BRCA mutations than other subtypes. A systematic examination of ERβ, HER2 and BRCA biomarkers could potentially be useful to diagnosis and identify patients with the histological subtypes of lung adenocarcinoma, who might benefit from the further individualized treatment of anti-hormone, anti-HER2 and/or PARP inhibitors therapeutics.

[Research Progress of Targeted Therapy for HER2 Gene in Advanced Non-small Cell Lung Cancer]

Lung cancer is the most common malignancy tumor. Non-small cell lung cancer (NSCLC) accounts for about 85% of lung cancer. Human epidermal growth factor receptor-2 (HER2) is a tyrosine kinase receptor in ERBB/HER family, which activates downstream signal transduction with other family members such as epidermal growth factor receptor (EGFR). HER2 gene mutation is closely related to the progression of many epithelial cell cancers. Tumors with high expression of HER2 show strong metastasis and invasion ability, poor sensitivity to chemotherapy, and are prone to relapse. At present, lung cancer driven gene targeted therapy has made rapid progress. Although the frequency of HER2 gene mutation in NSCLC is lower than that of EGFR, its driving mechanism in lung cancer is clear and partial targeted therapy is effective, which may become a new standard treatment in the future. This review focuses on the research progress of HER2 gene mutation in the treatment of NSCLC.
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Molecular testing and targeted therapy for non-small cell lung cancer: Current status and perspectives

Molecular testing has become a mandatory component of the non-small cell lung cancer (NSCLC) management. The detection of EGFR, BRAF and MET mutations as well as the analysis of ALK, ROS1, RET and NTRK translocations have already been incorporated in the NSCLC diagnostic standards, and the inhibitors of these kinases are in routine clinical use. There are emerging biomarkers, e.g., KRAS G12C substitutions and HER2 activating alterations, which are likely to enter NSCLC guidelines upon the approval of the corresponding drugs. In addition to genetic examination, NSCLCs are usually subjected to the analysis of PD-L1 protein expression in order to direct the use of immune checkpoint inhibitors. Comprehensive NSCLC testing for multiple predictive markers requires the analysis of distinct biological molecules (DNA, RNA, proteins) and, therefore, the involvement of different analytical platforms (PCR, DNA sequencing, immunohistochemistry, FISH). There are ongoing efforts aimed at the integration of multiple NSCLC molecular assays into a single diagnostic pipeline.

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.

A pan-cancer analysis of HER2 index revealed transcriptional pattern for precise selection of HER2-targeted therapy

Background

The prevalence of HER2 alterations in pan-cancer indicates a broader range of application of HER2-targeted therapies; however, biomarkers for such therapies are still insufficient and limited to breast cancer and gastric cancer.

Methods

Using multi-omics data from The Cancer Genome Atlas (TCGA), the landscape of HER2 alterations was exhibited across 33 tumor types. A HER2 index was constructed using one-class logistic regression (OCLR). With the predictive value validated in GEO cohorts and pan-cancer cell lines, the index was then applied to evaluate the HER2-enriched expression pattern across TCGA pan-cancer types.

Findings

Increased HER2 somatic copy number alterations (SCNAs) could be divided into two patterns, focal- or arm-level. The expression-based HER2 index successfully distinguished the HER2-enriched subtype from the others and provided a stable and superior performance in predicting the response to HER2-targeted therapies both in breast tumor tissue and pan-cancer cell lines. With frequencies varying from 12.0% to 0.9%, tumors including head and neck squamous tumors, gastrointestinal tumors, bladder cancer, lung cancer and uterine tumors exhibited high HER2 indices together with HER2 amplification or overexpression, which may be more suitable for HER2-targeted therapies. The BLCA.3 and HNSC.Basal were the most distinguishable subtypes within bladder cancer and head and neck cancer respectively by HER2 index, implying their potential benefits from HER2-targeted therapies.

Interpretation

As a pan-cancer predictive biomarker of HER2-targeted therapies, the HER2 index could help identify potential candidates for such treatment in multiple tumor types by combining with HER2 multi-omics features. The discoveries of our study highlight the importance of incorporating transcriptional pattern into the assessment of HER2 status for better patient selection.

Funding

The National Key Research and Development Program of China; Clinical Research and Cultivation Project of Shanghai ShenKang Hospital Development Center.

Is There a Role for Multiple Lines of Anti-HER2 Therapies Administered Beyond Progression in HER2-Mutated Non-Small Cell Lung Cancer? A Case Report and Literature Review

Oncogene-addicted non-small cell lung cancer (NSCLC) comprises a number of distinct disease subtypes, each of which is characterised by druggable genetic alterations. Among them, the receptor tyrosine kinase protein human epidermal receptor 2 (HER2) is occasionally found deregulated via gene mutation and/or amplification and/or protein overexpression. HER2 mutation, in particular, is a relatively rare condition which occurs in 1-4% of NSCLC patients, especially in those with adenocarcinoma histology and a never/light smoking history. However, the clinical relevance of a HER2 mutation in NSCLC relies on the fact that this genetic alteration has been associated with sensitivity to anti-HER2 therapies such as the monoclonal antibody trastuzumab or the pan-HER-tyrosine kinase inhibitor poziotinib. Here we describe the case of a NSCLC patient with an activating exon 20 G776VinsC mutation in the HER2 gene who responded well to multiple lines of trastuzumab-based therapies administered beyond progression and poziotinib given sequentially. In this specific case, the discovery of a druggable genetic alteration such as a mutation in the HER2 gene allowed for long-term control of the disease through the use of highly effective anti-HER2 therapies.