Impact of HER2 gene and protein status on the treatment outcome of cisplatin-based chemoradiotherapy for locally advanced non-small cell lung cancer

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.

Deciphering the Impact of HER2 Alterations on Non-Small-Cell Lung Cancer: From Biological Mechanisms to Therapeutic Approaches

Despite the recent increase in the number of types of treatments, non-small-cell lung cancer (NSCLC) remains the major cause of death from cancer worldwide. So, there is an urgent need to develop new therapeutic strategies. The HER2 gene codes for tyrosine kinase receptor whose alterations are known to drive carcinogenesis. HER2 alterations, including amplification, mutations, and overexpression, have been mainly described in breast and gastric cancers, but up to 4% of NSCLC harbor actionable HER2 mutations. HER2-targeted therapy for NSCLC with trastuzumab, pertuzumab, and trastuzumab emtansine has failed to demonstrate an improvement in survival. Nevertheless, recent data from phase II trials have shed light on promising specific therapies for HER2-mutant NSCLC such as trastuzumab deruxtecan. Herein, we aimed to provide an updated review on the biology, epidemiology, molecular testing, and therapeutic strategies for NSCLC with HER2 molecular alterations.

HER2-Altered Non-Small Cell Lung Cancer: Biology, Clinicopathologic Features, and Emerging Therapies

Multiple oncogenic molecular alterations have been discovered that serve as potential drug targets in non-small cell lung cancer (NSCLC). While the pathogenic and pharmacological features of common targets in NSCLC have been widely investigated, those of uncommon targets are still needed to be clarified. Human epidermal growth factor receptor 2 (HER2, ERBB2)-altered tumors represent a highly heterogeneous group of diseases, which consists of three distinct situations including mutation, amplification and overexpression. Compared with breast and gastric cancer, previous studies have shown modest and variable results of anti-HER2 treatments in lung cancers with HER2 aberrations, thus effective therapies in these patients represent an unmet medical need. By far, encouraging efforts towards novel treatment strategies have been made to improve the clinical outcomes of these patients. In this review, we describe the biological and clinicopathological characteristics of HER2 alterations and systematically sum up recent studies on emerging therapies for this subset of patients.

Targeting HER2 in non-small-cell lung cancer (NSCLC): a glimpse of hope? An updated review on therapeutic strategies in NSCLC harbouring HER2 alterations

Non-small-cell lung cancer (NSCLC) harbouring HER2 alterations is now considered a distinct molecular subtype. The activation of HER2 in NSCLC occurs via three mechanisms, i.e. gene mutation (1%-4% of cases), gene amplification (2%-5%) and protein overexpression (2%-30%), with different prognostic and predictive outcomes. So far, non-selective tyrosine kinase inhibitors (TKIs) have shown a minor benefit in HER2-mutant NSCLC patients with objective response rates (ORRs) ranging from 0% to 19%. Trastuzumab-based chemotherapy was not found to be superior to chemotherapy alone [median progression-free survival (PFS) 6.1 versus 7 months, respectively] and dual HER2 antibody blockade with trastuzumab and pertuzumab had limited efficacy (ORR 13%-21%). In contrast, novel more selective HER2 TKIs such as poziotinib and pyrotinib have shown a promising activity in HER2-mutant pre-treated NSCLC patients, with response rates up to 38% and 44%, respectively. The most encouraging data come from phase II studies that evaluated the antibody–drug conjugates (ADCs) ado-trastuzumab–emtansine and trastuzumab–deruxtecan in patients with HER2-mutant NSCLC, with response rates of 50% and 62%, respectively. These agents are bringing hope to the management of HER2-altered NSCLC. Moreover, a paradigm shift from monotherapies towards combinations of agents with distinct mechanisms of action, such as ADCs with irreversible TKIs or immune checkpoint inhibitors, is already taking place and will change the therapeutic landscape of HER2-driven NSCLC. This paper provides a practical, concise and updated review on the therapeutic strategies in NSCLC with HER2 molecular alterations.

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Activation of Her2 in NSCLC occurs via gene mutation, amplification or protein overexpression.

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Selective Her2 TKIs like poziotinib and pyrotinib induced responses in up to 44% of pre-treated Her2-mutant NSCLC patients.

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ADCs trastuzumab–emtansine and trastuzumab–deruxtecan showed impressive response rates in 62% of Her2-mutant NSCLC patients.

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Ongoing studies evaluating combination strategies may help improve the therapeutic landscape in Her2-dependent NSCLC.

Antibody Drug Conjugates in Lung Cancer: State of the Current Therapeutic Landscape and Future Developments

While both targeted therapy and immunotherapy-based strategies have emerged as frontline standard-of-care for patients with advanced lung cancer, acquired resistance and disease progression remain inevitable in most cases. Chemotherapy is a common salvage option in this scenario, but is limited by a relatively narrow therapeutic index. The emergence of antibody-drug conjugates (ADCs) offer an appealing alternative. ADCs couple the specificity of a monoclonal antibody with the cytotoxic effects of chemotherapy to facilitate the targeted delivery of cytotoxic payloads directly to cancer cells. Here, we review the general structure and function of ADCs, followed by a discussion of emerging ADCs in lung cancer and the future applications of this increasingly relevant class of novel agents.

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.

Progress in Treatment of Non-Small Cell Lung Cancer Harboring HER2 Aberrations

Epidermal growth factor receptor 2 (HER2/ErbB2/neu), a member of ErbB receptor tyrosine kinase family, forms homo- or heterodimers with ErbB1 (HER1/EGFR), ErbB3 (HER3), or ErbB4 (HER4), to activate signal transduction pathways and promote proliferation, differentiation and tumorigenesis. Preliminary clinical trials of monoclonal antibodies, antibody conjugates and small-molecule tyrosine kinase inhibitors targeting HER2 have indicated that HER2 is a potential therapeutic target in non-small cell lung cancer (NSCLC). HER2 aberrations in NSCLC patients mainly include mutation, amplification, and overexpression. While there are significant differences in the outcome of NSCLC with these HER2 changes, no consensus has been reached for the incidence, detection method and targeted treatments for the three types of HER2 aberration. HER2 mutation is generally considered to have more clinical relevance and response to HER2-targeted therapies. In this review, we discuss HER2 alterations in NSCLC, including diagnostic challenges and treatment strategies particular to the HER2 mutation.

Gefitinib induction followed by chemoradiotherapy in EGFR-mutant, locally advanced non-small-cell lung cancer: LOGIK0902/OLCSG0905 phase II study

Background

The role of epidermal growth factor receptor (EGFR)-tyrosine kinase inhibitor (TKI) induction coupled with standard concurrent chemoradiotherapy (CRT) is unclear in unresectable, stage III, EGFR-mutant non-small-cell lung cancer (NSCLC). Therefore, a phase II trial was conducted to evaluate the efficacy and safety of gefitinib induction followed by CRT in this disease setting.

Patients and methods

Patients with unresectable, EGFR-mutant, stage III NSCLC were administered gefitinib monotherapy (250 mg/day) for 8 weeks. Subsequently, patients without disease progression during induction therapy were administered cisplatin and docetaxel (40 mg/m² each) on days 1, 8, 29, and 36 with concurrent radiotherapy at a total dose of 60 Gy. The primary endpoint was the 2-year overall survival (OS) rate, which was hypothesized to reach 85%, with a threshold of the lower limit of 60%.

Results

Twenty patients (median age: 66 years; male/female: 9/11; histology: 20 adenocarcinoma; stage IIIA/IIIB: 9/11; and exon 19/21: 10/10) were enrolled. The 2-year OS rate was 90% (90% confidence interval: 71.4% to 96.8%), indicating that this trial met the primary objective. The overall response rate and 1- and 2-year progression-free survival rates were 85.0%, 58.1%, and 36.9%, respectively. Grade ≥3 adverse events (>10%) included hepatic toxicity during the induction phase and neutropenia and febrile neutropenia in the CRT phase. Radiation pneumonitis grade ≥3 or treatment-related death did not occur.

Conclusions

This is the first prospective study to demonstrate the favorable efficacy and safety of EGFR-TKI induction followed by standard CRT in EGFR-mutant, stage III NSCLC. Further confirmatory studies are needed.

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This is the first prospective study evaluating gefitinib induction followed by CRT in EGFR-mutated, locally advanced NSCLC.

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The 2-year OS rate was 90% (90% confidence interval: 71.4% to 96.8%), indicating that this trial met the primary objective.

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The objective response rate throughout the treatment protocol was 85.0% (17 of 20).

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The safety findings were consistent with the known safety profiles of all agents administered.

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Our results might raise a critical point that needs to be evaluated in further studies to improve the cure rate.

Efficacy of Combination Chemo-Immunotherapy as a First-Line Treatment for Advanced Non-Small-Cell Lung Cancer Patients With HER2 Alterations: A Case Series

Objective

Although the treatment of non-small-cell lung cancer (NSCLC) patients with human epidermal growth factor receptor 2 (HER2) alterations has been studied for years, the overall response rate (ORR) of these patients is still unsatisfactory, and more therapeutic strategies are needed. Little is known about the combination of chemo- and immunotherapy in HER2-altered lung cancer treatment.

Materials and Methods

We report five cases of advanced NSCLC with HER2 insertion mutation or amplification treated with immunotherapy combined with chemotherapy as the first-line treatment. The HER2 alteration type, duration of treatment and survival were also analyzed.

Results

The five advanced NSCLC patients, three with HER2 mutations and two with HER2 amplifications, received chemo-immunotherapy as the first-line treatment. The average patient age was 54.6 years. Three patients were females, and two were males. Among all the patients, only one had a smoking history. The immunotherapies used were as follows: two patients were treated with sintilimab, and three patients were treated with pembrolizumab. Only one patient had squamous carcinoma, and she was also the only patient with a complete response (CR). The progression-free survival (PFS) ranged from 2-12 months, with a median PFS of 8.0 months.

Conclusions

Chemo-immunotherapy may be a promising first-line treatment option for NSCLC patients with HER2 alterations. Further clinical trials are required to confirm this therapeutic option.

Differential Second Primary Malignancy Occurrence After Breast Cancer According to HER2 Status: A Population-Based Study

PURPOSE

Our study aims to analyze the association between HER2 status of breast cancer (BC) and second primary malignancy (SPM) occurrence.

MATERIALS AND METHODS

Based on BC patients registered between 2010 and 2018 in the NCI SEER database, we utilized standardized incidence ratio (SIR) and Poisson regression to quantify SPM occurrence compared with the general population. Then, adjusted for competing death risk, cumulative incidence function and Gray's test were adopted to estimate the probability of SPM. Subsequent proportional subdistribution hazards regression was executed to identify the HER2 status impact on SPM risk. Finally, survival analysis was performed.

RESULTS

A total of 409,796 first BC patients were included and 18,283 were identified with at least one SPM. The SIR of SPM after HER2+ BC was significantly lower than HER2- BC (1.03 vs 1.13; RR, 0.92; 95% CI, 0.88-0.96; p<0.001). The predominantly declining SPM risk was only observed for second BC (RR, 0.89; 95% CI, 0.82-0.96; p=0.003) and lung cancer (RR, 0.84; 95% CI, 0.74-0.95; p=0.007). Furthermore, competing risk analysis verified the protective effect of HER2 positivity status on SPM occurrence. The 5-year cumulative incidence of SPM following HER2+ and HER2- BC were 4.09% and 5.16%, respectively (p<0.001). In addition, among patients suffering from SPM, HER2 positivity status contributed to better overall survival.

CONCLUSION

It is demonstrated that HER2+ BC patients had lower SPM incidence, which was remarkable for second BC and lung cancer.

Targeting HER2 Alterations in Non–Small-Cell Lung Cancer: A Comprehensive Review

PURPOSE

HER2 is a critical gene that drives various solid tumors in addition to those of breast cancer. For example, HER2 plays a role in non–small-cell lung cancer (NSCLC). Overexpression, amplification, and point mutations in HER2 have been described in patients with NSCLC; however, the potential roles of these alterations remain unclear.

METHODS

We summarize the evidence regarding the distinct impacts of different HER2 aberrations on antitumor agents. Also, we update the therapeutic efficacy of HER2-targeted agents, including anti-HER2 antibodies, antibody-drug conjugates, and small-molecule tyrosine kinase inhibitors, tested in HER2-aberrant NSCLC.

RESULTS

Although these drugs are not yet standard treatments, certain patients may benefit from these therapies. In this review, we aim to provide an improved understanding of HER2 aberrations in NSCLC, including NSCLC biology and the impacts of each aberration on prognosis and standard treatment. We also highlight the potential of novel anti-HER2 therapies approved by regulatory bodies and those in clinical development.

CONCLUSION

Compared with HER2 amplification or overexpression, HER2 mutations, especially HER2 exon 20 mutations, are emerging as the most clear targetable driver for HER2-directed therapies in lung cancer. De novo and inducible HER2 pathway activation need to be differentially managed. Further investigations with new strategies are needed.

The force of HER2 - A druggable target in NSCLC?

Since several years targeted therapy has been part of treatment in NSCLC in subsets of patients with specific genetic alterations. One of these alterations involves HER2, a member of the ERBB family of tyrosine kinase receptors. Despite that HER2 alterations in NSCLC have been studied for years, there is still no consensus about subgroup definitions. In this review HER2 alterations in NSCLC are discussed, including diagnostic challenges and treatment strategies. Three principal mechanisms of HER2 alterations can be identified: HER2 protein overexpression, HER2 gene amplification and HER2 gene mutations. There are several methods for the detection of HER2 "positivity" in NSCLC, but no gold standard has been established. Laboratory methods for assessment of HER2 positivity in NSCLC include immunohistochemistry (IHC) for protein overexpression and fluorescent in situ hybridization (FISH) and next generation sequencing (NGS) for genetic alterations. Many trials testing HER2 targeted therapy in HER2 altered NSCLC has not lead to a renewed standard of care for this group of patients. Therefore, today the (re)search on how to analyse, define and treat HER2 alterations in NSCLC continues. Still there is no consensus about HER2 subgroup definitions and results of the many trials studying possible treatment strategies are inconclusive. Future research should focus on the most important missing link, whether all HER2 alterations are relevant oncogenic drivers and whether it should be considered as a therapeutic target in NSCLC.

Immune Checkpoint Inhibitors for the Treatment of Unresectable Stage III Non-Small Cell Lung Cancer: Emerging Mechanisms and Perspectives

There has been no improvement in outcome for patients with unresectable locally advanced (stage III) non-small cell lung cancer (NSCLC) for more than 10 years. The standard treatment for these patients is definitive concurrent chemotherapy and radiation (CCRT). Although the goal of treatment in this setting is to achieve a cure, most patients progress and their prognosis is poor, with a 5-year survival rate of 15-30%. There is thus an urgent need for the development of novel anticancer treatments in this patient population. Recent advances in cancer immunotherapy have led to a marked improvement in clinical outcome for advanced NSCLC. Such immunotherapy mainly consists of the administration of immune checkpoint inhibitors (ICIs) such as antibodies to cytotoxic T lymphocyte-associated protein-4 (CTLA-4) or to either programmed cell death-1 (PD-1) or its ligand PD-L1. Durvalumab (MEDI4736) is a high-affinity human immunoglobulin G1 monoclonal antibody that blocks the binding of PD-L1 on tumor cells or antigen-presenting cells to PD-1 on T cells. The PACIFIC study recently evaluated consolidation immunotherapy with durvalumab versus placebo administered after concurrent chemoradiotherapy (CCRT) in patients with unresectable stage III NSCLC. It revealed a significant improvement in both progression-free and overall survival with durvalumab, and this improvement was associated with a favorable safety profile. This achievement has made durvalumab a standard of care for consolidation after CCRT in patients with unresectable stage III NSCLC, and it has now been approved in this setting by regulatory agencies in the United States, Canada, Japan, Australia, Switzerland, Malaysia, Singapore, India, and the United Arab Emirates. In this review, we briefly summarize the results of the PACIFIC trial, including those of post hoc analysis, and we address possible molecular mechanisms, perspectives, and remaining questions related to combined treatment with CCRT and ICIs in this patient population.

Pilot evaluation of a HER2 testing in non-small-cell lung cancer

AIMS

HER2-positivity pattern in the specimens of immunohistochemistry (IHC) and fluorescence in situ hybridisation (FISH) has been hardly reported in non-small-cell lung cancer (NSCLC).

METHODS

We evaluated the characteristics of HER2-positivity pattern in formalin-fixed paraffin-embedded samples using IHC and FISH in 15 patients enrolled in a larger prospective cohort study to survey a HER2-positive NSCLC.

RESULTS

As for the immunostaining pattern, most specimens (79%) demonstrated incomplete or mixed-typed membranous immunoreactivity with heterogeneity, resembling that observed in gastric cancer rather than breast cancer. Concordance between IHC-positivity and FISH-positivity was 87.5% according to the criteria for breast cancer scoring system. On application of the gastric cancer scoring system to the examined tumours, the IHC score increased in the seven (43.8%) specimens, and the concordance between IHC positivity and FISH positivity rose to 93.8%.

CONCLUSIONS

In our pilot series, the pattern of IHC reactivity closely resembled that observed in gastric cancer rather than breast cancer.

TRIAL REGISTRATION NUMBER

000017003.

A Prospective Cohort Study to Define the Clinical Features and Outcome of Lung Cancers Harboring HER2 Aberration in Japan (HER2-CS STUDY)

BACKGROUND

Human epidermal growth factor 2 (HER2) is a potential driver oncogene. Although HER2-targeted precision therapy has been tested in non-small cell lung cancer (NSCLC), the demographic characteristics of HER2-positive NSCLC have not been systematically defined.

METHODS

Patients with pathologically confirmed stage IIIB/IV or recurrent NSCLC, Eastern Cooperative Oncology Group performance status 0 to 2, were prospectively registered. HER2 immunohistochemistry (IHC) and fluorescence in situ hybridization (FISH) assays were performed to screen patients. HER2 mutations were identified by using direct gene sequencing. The aim of this study was to clarify the frequency, characteristics, and outcome of HER2-positive NSCLC. HER2 was defined as positive if the tumor harbored IHC3+, IHC2+/FISH+, or exon 20 insertion mutations.

RESULTS

Of the 1,126 tumors screened, 34 (3.0%) were IHC3+, and 34 (3.0%) were IHC2+/FISH+. Among the 724 epidermal growth factor receptor wild-type tumors, 21 (2.9%) were HER2-mutant tumors, including A775-G776insYVMA (n = 15). Interestingly, the IHC3+ tumors and mutant tumors were entirely exclusive. Female patients had HER2-mutant tumors more frequently, whereas both IHC3+ and IHC2+/FISH+ tumors were detected more often in male subjects and smokers. Patients with an HER2-aberrant tumor had a significantly worse prognosis than those with epidermal growth factor receptor-positive and anaplastic lymphoma kinase-positive tumors, possibly due to the low proportion that received HER2-targeted therapies (n = 15 [26%]) and low response rates of 0% and 14% in patients with HER2-overexpressing and HER2-mutant tumors, respectively.

CONCLUSIONS

This prospective large-scale cohort study is the first to show comprehensively the frequency and clinical demographic characteristics of those with HER2-positive advanced lung tumors in detail, providing critical historical data for future drug development against HER2-positive NSCLC. Future treatment strategies would be developed stratified according to the types of HER2 aberrations.

TRIAL REGISTRY

UMIN Registration No. 000017003; URL: https://upload.umin.ac.jp/cgi-open-bin/ctr_e/ctr_view.cgi?recptno=R000019691.

Recent trends in the treatment of unresectable stage III non-small-cell lung cancer

Approximately 20-25% of non-small-cell lung cancer (NSCLC) is diagnosed when the disease has progressed to clinical stage III. At this stage, and even if the cancer is considered unresectable, the treatment strategy should aim to achieve a cure. At the time of the initial diagnosis, it is necessary for medical oncologists to devise the best treatment strategy for each patient by composing a multidisciplinary treatment team including thoracic surgeons and radiation oncologists. In this review, we summarize prior pivotal clinical trials in unresectable clinical stage III NSCLC. Furthermore, we review very recent clinical trials evaluating the efficacy of immune checkpoint inhibitors in the treatment of NSCLC.

S-1-based concurrent chemoradiotherapy in the treatment of locally advanced non-small cell lung cancer: A systematic review and meta-analysis protocol

BACKGROUND

Lung cancer is the leading cause of cancer-related deaths in the world, and non-small cell lung cancer accounts for > 75% of all lung cancer cases. Cisplatin-based concurrent chemoradiotherapy has become the standard treatment for locally advanced non-small cell lung cancer (NSCLC). Third-generation chemotherapy agents plus cisplatin have been most commonly used in concurrent chemoradiotherapy, which is also associated with more adverse effects and acute toxicities. S-1 as an oral chemotherapeutic agent exhibits higher antitumor activity, less adverse effects, and better biological availability. Recently, studies illustrated S-1-based concurrent chemoradiotherapy also had excellent effects in the treatment of locally advanced NSCLC.

METHODS

A systematic literature search will be performed through February 2018 using MEDLINE, EMBASE, the Cochrane Central Register of Controlled Trials, and Google Scholar for relevant articles published in any language. Randomized controlled trials and prospective comparative studies will be included. All meta-analyses will be performed using Review Manager software. The quality of the studies will be evaluated using the guidelines listed in the Cochrane Handbook. The Preferred Reporting Items for Systematic Reviews and Meta-Analyses statements will be followed until the findings of the systematic review and meta-analysis are reported.

RESULTS

The results of this systematic review and meta-analysis will be published in a peer-reviewed journal.

CONCLUSION

Our study will draw an objective conclusion of the efficacy and safety of S-1-based chemoradiotherapy in the treatment of locally advanced unresectable NSCLC and provides level I evidence for clinical decision makings.

A Phase II Study of Trastuzumab Emtansine in HER2-Positive Non-Small Cell Lung Cancer

Trastuzumab emtansine (T-DM1), an anti-erb-b2 receptor tyrosine kinase 2 (HER2) antibody-drug conjugate, has been shown to significantly improve survival in HER2-positive breast cancer. We report a phase II trial of T-DM1 monotherapy in relapsed NSCLC with documented HER2 positivity (an immunohistochemistry [IHC] score of 3+, both an IHC score of 2+ and fluorescence in situ hybridization positivity, or exon 20 mutation). This study was terminated early because of limited efficacy. The demographic characteristics in the 15 assessable patients were as follows: median age, 67 years; male sex, 47%; performance status of 0 to 1, 80%; HER2 status IHC 3+, 33%; HER status IHC 2+/fluorescence in situ hybridization-positive, 20%; and exon 20 mutation, 47%. The median number of delivered cycles was 3 (range 1-11). One patient achieved a partial response with an objective response rate of 6.7% (90% confidence interval: 0.2-32.0). With a median follow-up time of 9.2 months, the median progression-free survival time and median survival time were 2.0 and 10.9 months, respectively. Grade 3 or 4 adverse events included thrombocytopenia (40%) and hepatotoxicity (20%) without any treatment-related deaths. T-DM1 had a limited efficacy for HER2-positive NSCLC in our cohort. Applying the concept of precision medicine to tumors appears challenging; thus, additional molecular approaches are warranted.

Precision medicine approaches to lung adenocarcinoma with concomitant MET and HER2 amplification

BACKGROUND

Patient-derived xenograft (PDX) models are important tools in precision medicine and for the development of targeted therapies to treat cancer patients. This study aimed to evaluate our precision medicine strategy that integrates genomic profiling and preclinical drug-screening platforms, in order to personalize cancer treatments using PDX models.

METHODS

We performed array-comparative genomic hybridization, microarray, and targeted next-generation sequencing analyses, in order to determine the oncogenic driver mutations. PDX cells were obtained from PDXs and subsequently screened in vitro with 17 targeted agents.

RESULTS

PDX tumors recapitulated the histopathologic and genetic features of the patient tumors. Among the samples from lung cancer patients that were molecularly-profiled, copy number analysis identified unique focal MET amplification in one sample, 033 T, without RTK/RAS/RAF oncogene mutations. Although HER2 amplification in 033 T was not detected in the cancer panel, the selection of HER2-amplified clones was found in PDXs and PDX cells. Additionally, MET and HER2 overexpression were found in patient tumors, PDXs, and PDX cells. Crizotinib or EGFR tyrosine kinase inhibitor treatments significantly inhibited cell growth and impaired tumor sphere formation in 033 T PDX cells.

CONCLUSIONS

We established PDX cell models using surgical samples from lung cancer patients, and investigated their preclinical and clinical implications for personalized targeted therapy. Additionally, we suggest that MET and EGFR inhibitor-based therapy can be used to treat MET and HER2-overexpressing lung cancers, without receptor tyrosine kinase /RAS/RAF pathway alterations.

Lung adenocarcinoma harboring concomitant SPTBN1-ALK fusion, c-Met overexpression, and HER-2 amplification with inherent resistance to crizotinib, chemotherapy, and radiotherapy

Crizotinib is a multi-targeted tyrosine kinase inhibitor (TKI) with activity against mesenchymal-epithelial transition factor (MET) and anaplastic lymphoma kinase (ALK). However, the concomitant oncogenic drivers may affect the sensitivity of crizotinib. Herein, we present a 69-year-old never-smoker Chinese male with advanced lung adenocarcinoma harboring concomitant spectrin beta non-erythrocytic 1 (SPTBN1)-ALK fusion, c-Met overexpression, and human epidermal growth factor receptor-2 (HER-2) amplification with inherent resistance to crizotinib, chemotherapy, and radiotherapy. Although the patient received timely and comprehensive treatment, the overall survival was only 8 months. Therefore, c-Met overexpression, HER-2 gene amplification, and SPTBN1-ALK gene fusion can coexist in lung adenocarcinoma and may become a potential biomarker of cancer refractory to crizotinib, chemotherapy, and radiotherapy as well as of a relatively poor prognosis. In addition, the novel SPTBN1-ALK fusion gene may become a potential target for anti-tumor therapy.

Trastuzumab Emtansine in HER2+ Recurrent Metastatic Non-Small-Cell Lung Cancer: Study Protocol

The treatment outcome has been unsatisfactory for patients with non-small-cell lung cancer (NSCLC) refractory to standard first-line chemotherapy. Trastuzumab emtansine (T-DM1), an anti-HER2 antibody conjugated with a vinca alkaloid, has been approved for clinical use in HER2+ breast cancer in many countries. Approximately 5% of NSCLC tumors possess HER2 alterations, and T-DM1 has shown excellent antitumor effects against HER2+ lung cancer cell lines in preclinical models. Therefore, we hypothesized that T-DM1 could significantly inhibit the growth of HER2+ lung cancers. We have launched a nonrandomized phase II trial of T-DM1 monotherapy for patients with HER2+ lung cancers. The major eligibility criteria are as follows: age ≥ 20 years, pathologically diagnosed NSCLC with documented HER2 positivity (immunohistochemistry 3+, both immunohistochemistry 2+ and fluorescence in situ hybridization positive, or exon 20 insertion mutation), and previous chemotherapy. Thirty patients will receive T-DM1 3.6 mg/kg every 3 weeks. The primary endpoint is the overall response rate. This trial will provide information on whether T-DM1 monotherapy is effective against HER2+ lung cancer.

[Role of HER2 in NSCLC]

过去几年中, 随着分子靶向药物的引入, 非小细胞肺癌(non-small cell lung cancer, NSCLC)的药物治疗策略发生了巨大变化, 向基于组织学和分子水平的治疗手段转变。表皮生长因子受体(epidermal growth factor receptor, EGFR)突变、Kirsten鼠肉瘤(Kirsten rat sarcoma, KRAS)癌基因突变、间变淋巴瘤激酶(anaplastic lymphoma kinase, ALK)重排等的发现, 影响着NSCLC治疗的发展。最近, 对人表皮生长因子受体2(human epidermal growth factor receptor 2, HER2)研究重燃兴趣, 这一基因改变与NSCLC对不同酪氨酸激酶抑制剂(tyrosine kinase inhibitors, TKIs)的敏感性相关, 其具有可能的预测作用, HER2扩增可能是EGFR突变肿瘤对EGFR-TKIs获得性耐药的机制之一。其次, HER2突变可能阐明一条新的靶向治疗NSCLC的策略。本文将对NSCLC中HER2异常调节发挥的作用做一简要介绍。

NSCLC and HER2: between lights and shadows

The therapeutic landscape of non-small-cell lung cancer (NSCLC) has dramatically changed in the last few years with the introduction of molecularly targeted agents, leading to unprecedented results in lung tumors with a paradigmatic shift from a "one size fits all" approach to an histologic and molecular-based approach. The discovery of epidermal growth factor receptor (EGFR) mutations in NSCLC in 2004 and the marked response to the EGFR tyrosine kinase inhibitor gefitinib, in a small subset of patients harboring these genetic abnormalities, stimulated the study of other kinase mutants involvement in NSCLC. The incredible story of ALK rearranged tumors, with the rapid Food and Drug Administration approval of Crizotinib after only 4 years from the discovery of EML4-ALK translocation in NSCLC, has profoundly influenced the concept of drug development in NSCLC, paving the way to a novel series of molecularly selected studies with specific inhibitors. The identification of these oncogenic drivers has dramatically changed the genetic landscape of NSCLC moving away from the old concept of a large indistinct histological entity to a combination of rare clinically relevant molecular subsets. Recently, a renewed interest has been emerging on the human epidermal growth factor-2 (HER2) pathway. Genetic aberrations of this signaling pathway have been reported over time to be associated in NSCLC with different sensitivity to the EGFR tyrosine kinase inhibitors, to have a possible prognostic role and more recently HER2 amplification has been emerged as a possible mechanism in EGFR-mutated tumors of acquired resistance to the EGFR tyrosine kinase inhibitors. In addition, dysregulation of the HER2 pathway, in particular HER2 mutations (mostly, in-frame exon 20 insertions), may represent a possible novel therapeutic target in NSCLC, paving the way for a new generation of targeted agents in NSCLC. Since anecdotal case reports of clinical activity of anti-HER2 agents in NSCLC patients with HER2 mutations, several targeted agents have been evaluated in HER2-mutated patients, generating a growing interest upon this oncogenic driver, leading to the design of molecularly selected trials with anti-HER2 compounds and the rediscover of hastily thrown out drugs, such as neratinib. The aim of this article is to provide an overview of the role of HER2 dysregulation in NSCLCs, trying to throw a light not only on the strengths but also the weaknesses of the studies conducted so far. It is a long way to the clinical implementation of these biomarkers and probably the increasing use of next generation sequencing techniques, the creation of large multi-institutional molecular testing platforms and the design of rationally based trials can get closer personalized medicine in NSCLC.

Targeting HER2 in the treatment of non-small cell lung cancer

Oncogenic driver mutations have emerged as major treatment targets for molecular therapies in a variety of cancers. HER2 positivity has been well-studied in breast cancer, but its importance is still being explored in non-small cell lung cancer (NSCLC). Laboratory methods for assessment of HER2 positivity in NSCLC include immunohistochemistry (IHC) for protein overexpression, fluorescent in situ hybridization (FISH) for gene amplification, and next generation sequencing (NGS) for gene mutations. The prognostic and predictive significance of these tests remain to be validated, with an emerging association between HER2 gene mutations and response to HER2 targeted therapies. Despite the assay used to determine the HER2 status of lung tumors, all patients with advanced HER2 positive lung adenocarcinoma should be evaluated for treatment with targeted agents. Several clinical approaches for inclusion of these drugs into patient treatment plans exist, but there is no defined algorithm specific to NSCLC.

Single-cell quantitative HER2 measurement identifies heterogeneity and distinct subgroups within traditionally defined HER2-positive patients

Human epidermal growth factor receptor 2 (HER2) is an important biomarker for breast and gastric cancer prognosis and patient treatment decisions. HER2 positivity, as defined by IHC or fluorescent in situ hybridization testing, remains an imprecise predictor of patient response to HER2-targeted therapies. Challenges to correct HER2 assessment and patient stratification include intratumoral heterogeneity, lack of quantitative and/or objective assays, and differences between measuring HER2 amplification at the protein versus gene level. We developed a novel immunofluorescence method for quantitation of HER2 protein expression at the single-cell level on FFPE patient samples. Our assay uses automated image analysis to identify and classify tumor versus non-tumor cells, as well as quantitate the HER2 staining for each tumor cell. The HER2 staining level is converted to HER2 protein expression using a standard cell pellet array stained in parallel with the tissue sample. This approach allows assessment of HER2 expression and heterogeneity within a tissue section at the single-cell level. By using this assay, we identified distinct subgroups of HER2 heterogeneity within traditional definitions of HER2 positivity in both breast and gastric cancers. Quantitative assessment of intratumoral HER2 heterogeneity may offer an opportunity to improve the identification of patients likely to respond to HER2-targeted therapies. The broad applicability of the assay was demonstrated by measuring HER2 expression profiles on multiple tumor types, and on normal and diseased heart tissues.

Anterior gradient 2 overexpression in lung adenocarcinoma

The histologic subtyping of the 2 major histotypes of nonsmall-cell lung cancer, that is, adenocarcinoma (AdC) and squamous cell carcinoma (SCC), is crucial to therapeutic decision making, but making this distinction can be a challenge. Querying the Oncomine database pinpointed anterior gradient 2 (AGR2) as being upregulated in lung AdC. On applying both quantitative real-time polymerase chain reaction and immunohistochemistry, this study tested the reliability of AGR2 status as a histotype-specific marker of lung AdC. AGR2 immunohistochemistry expression was semiquantitatively assessed in 120 cases of lung cancer (60 AdCs, 60 SCCs); 35 additional tissue samples from non-neoplastic lungs were considered as normal controls. To further support our findings, the expression of AGR2 mRNA was tested by quantitative real-time polymerase chain reaction in 30 of the considered cases (10 AdCs, 10 SCCs, and 10 normal lungs). AGR2 was consistently expressed in normal bronchial/bronchiolar columnar cells. Cases of AdC always expressed the protein (staining moderately in 30% and strongly in 70%), whereas none of the SCC cases strongly expressed AGR2 (staining was negative in 55%, weak in 33%, and moderate in 12%). AGR2 mRNA was significantly overexpressed in AdCs by comparison with SCCs (P=0.003) or normal lung tissue (P=0.002). AGR2 is upregulated in lung AdC (by comparison with either SCC or normal bronchial/bronchiolar columnar cells). AGR2 protein expression may support the histologic subtyping of nonsmall-cell lung cancer and be of clinical value in differentiating lung AdC from SCC.

ErbB2 expression through heterodimerization with erbB1 is necessary for ionizing radiation- but not EGF-induced activation of Akt survival pathway

PURPOSE

ErbB1-dependent Akt phosphorylation improves post-irradiation cellular survival. In the present study, we investigated the contribution of erbB2 as a heterodimerization partner of erbB1 in activation of Akt survival signaling after irradiation or EGF treatment.

MATERIALS AND METHODS

Pattern of receptor dimerization and protein phosphorylation were investigated by Western and immunoblotting as well as immunoprecipitation techniques. Residual DNA double-strand breaks (DNA-DSB) and clonogenic activity were analyzed by γH2AX and standard clonogenic assay. To knocked erbB2 expression siRNA was used.

RESULTS

In lung carcinoma cell lines A549 and H661, the erbB1-tyrosine kinase (TK) inhibitor erlotinib blocked EGF as well as ionizing radiation (IR)-induced Akt and DNA-PKcs phosphorylation. Targeting Akt and erbB1 induced cellular radiation sensitivity while, the erbB2-TK inhibitor AG825 neither affected phosphorylation of Akt and DNA-PKcs nor induced radiosensitization. ErbB2-siRNA and the anti-erbB2 antibody trastuzumab blocked IR-induced, but not EGF-stimulated Akt phosphorylation and impaired the repair of DNA-DSB. Likewise, IR but not EGF enhanced erbB1/erbB2 heterodimerization and resulted in the release of phosphorylated erbB2 cleavage products p135 and p95. Trastuzumab prevented radiation-induced formation of an active erbB1/erbB2 heterodimer and increased cellular radiation sensitivity. ErbB1- but not erbB2-TK inhibition stabilized erbB2 (p185) through preventing its cleavage.

CONCLUSIONS

The data indicates that ErbB2 through heterodimerization with erbB1 is necessary for the activation of Akt signaling following irradiation but not following EGF treatment.

Correlation between epidermal growth factor receptor mutations and expression of female hormone receptors in East-Asian lung adenocarcinomas

INTRODUCTION

Epidermal growth factor receptor (EGFR) mutations are more common in lung adenocarcinoma and in female patients of East-Asian origin. We aimed to assess the expression of female hormone receptors in East-Asian lung adenocarcinomas, their correlation with EGFR mutations, and prognostic significance.

METHODS

Estrogen receptor (ER)alpha, ERbeta, progesterone receptor (PR), and Her-2 expression were examined using immunohistochemical methods on 109 lung adenocarcinoma cases. EGFR mutations were analyzed by partially denaturing high performance liquid chromatography. Association of hormone receptor with clinical factors was assessed using the Fisher's exact test. Associations with survival were assessed using the Cox proportional hazard model.

RESULTS

Using scoring criteria routinely used for breast cancer, there were four (4%) ERalpha, one (1%) ERbeta, six (6%) PR, and one (1%) Her-2 positive cases. Considering any staining as positive, 14 (14%) ERalpha, 10 (9%) ERbeta, 12 (12%) PR, and 26 (24%) Her-2 cases were positive. Thirty-nine patients (39%) had EGFR mutations. ERalpha positivity was significantly associated with ERbeta and PR positivity. There were more EGFR mutations seen in tumors with ERbeta positivity (60%) compared with those with negative expression (37.9%), and there was a trend toward a poorer outcome for patients with tumor that were positive for ERbeta and Her-2.

CONCLUSIONS

We found that ERalpha, ERbeta, PR, and Her-2 expression in lung adenocarcinoma are present but limited. This suggests that hormonal influence may not be an important factor to account for the high prevalence of lung cancer among the East-Asian women.

Targeted therapy for nonsmall cell lung cancer: focusing on angiogenesis, the epidermal growth factor receptor and multikinase inhibitors

Chemotherapy used to be the only available option to fight advanced nonsmall cell lung cancer. Platinum-based medication combined with taxanes, vinca alkaloids, and antimetabolites improved patient survival rates. Unfortunately, neoplasmatic diseases remain a global killer because chemotherapy benefits have reached a plateau and most patients are diagnosed at the metastatic stage. The urgent need for therapeutic agents, along with advances in the knowledge of the molecular events of oncogenesis, has resulted in the development of medication that specifically targets processes and pathways critical for tumor growth, such as angiogenesis and the epidermal growth factor receptor. Initially, inhibiting these pathways managed to prolong patient survival, although not to the extent desired. Moreover, targeted therapy combined with conventional cytotoxic agents has shown no superiority to chemotherapy alone in terms of patient survival. Hence, numerous multidynamic agents have appeared in the hope that they might help fight nonsmall cell lung cancer. However, no group of patients who will hopefully gain maximum benefit from such interventions has been clearly identified yet. This paper presents current evidence with regard to such novel agents and angiogenesis and epidermal growth factor inhibitors.

The effect of HER2 expression on cisplatin-based chemotherapy in advanced non-small cell lung cancer patients

Introduction

The prognostic value of HER2 expression in patients with advanced non-small cell lung cancer remains controversial. The relationship between HER2 expression, and platinum resistance and patient survival, was investigated.

Methods

Seventy-three consecutive patients (median age, 61 years) with stage IIIB and IV non-small cell lung cancer, admitted between February 2004 and December 2006, were included in this study. Sixty-one patients received gemcitabine, given as two 1250 mg/m² doses on days 1 and 8 and, cisplatin, given as a 75 mg/m² dose on day 8. Twelve patients received vinorelbine, given as two 25 mg/m² doses on day 1 and 8, and cisplatin, given as a 75 mg/m² dose on day 1. Both treatment paradigms were repeated on a 21-day cycle. Tumor response was evaluated by comparing tumor size on computerized tomography scans before and after three cycles of chemotherapy. HER2 status was examined by immunohistochemical analysis of paraffin-embedded specimens.

Results

HER2 was positive in 21 of 73 patients (28.8%). Of the 21 patients with HER2 positivity, 13 (61.9%) responded to chemotherapy with either a complete response, partial remission, or evidence of stable disease. Of 52 HER2-negative patients, 48 (92.3%) exhibited a response to chemotherapy. The difference in response to therapy between HER2-positive and -negative patients was statistically significant (p = 0.003). The median overall survival duration for all patients was 13 months. Median overall survival time was 14 months for HER2-negative patients and 10 months for HER2-positive patients (log-rank p = 0.007).

Conclusion

Non-small cell lung cancer patients with high expression of HER2 exhibited resistance to cisplatin-based chemotherapies that are the standard treatment for this disease. Our results indicate that HER2 status may be a predictive and prognostic factor for cisplatin- based therapy response and disease survival.

Inhibition of non-small cell lung cancer cell proliferation and tumor growth by vector-based small interfering RNAs targeting HER2/neu

Amplification and over-expression of HER2/neu oncogene is found in diverse types of human cancers, and is closely related to tumor occurrence, metastasis, angiogenesis and chemotherapy resistance. Therapeutic agents targeting HER2/neu have been intensively addressed over the past decades. In non-small cell lung cancers (NSCLCs), the prevalence of HER2/neu activation, its role in prognosis, and its possible implications as a therapeutic target, are still to be elucidated. Here we show that the abundant or moderate over-expression of HER2/neu could be detected in both pulmonary adenocarcinoma and pulmonary large cell carcinoma cell lines. Stable knockdown of HER2/neu expression in the NSCLC cell line SPC-A-1 was achieved by vector-based small interfering RNAs (siRNAs), which consequently caused significant decrease in cell proliferation and clone forming efficiency, as well as cell cycle arrest at G(1) phase. Compared with the parental NSCLC cells, HER2/neu knockdown cells exhibited attenuated capacities in developing tumors in nude mice, and the growth tumors xenografts derived from these cells were dramatically regressed. These data provided direct evidence that HER2/neu signaling is essential for tumorigenicity of NSCLC cells, and suggested that siRNAs targeted to HER2/neu may provide a novel therapeutic strategy in the treatment of NSCLC, especially when combined with traditional therapeutics or via development of vector-based siRNAs of multiple targets that synergistically contribute to carcinogenesis, e.g. EGFR and HER2/neu.