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

Clinicopathologic and Molecular Characteristics of HER2 (ERBB2)-Altered Non-Small Cell Lung Cancer: Implications for Precision Medicine

The heterogeneous relationship between protein expression, amplification, and mutations in human epidermal growth factor receptor 2 (HER2) in non-small cell lung cancer (NSCLC) and the optimal methods for detecting these alterations remain unclear. We aimed to elucidate the clinicopathological and molecular characteristics of HER2-altered NSCLC and investigate practical approaches for identifying patients who might benefit from HER2-targeted therapies. Using next-generation sequencing data from 1680 individuals, we searched for patients with HER2-altered NSCLCs, including amplifications and mutations. Clinicopathological data and tissue slides were reviewed. Immunohistochemistry (IHC) and silver in situ hybridization were performed according to the American Society of Clinical Oncology/College of American Pathologists guidelines. Our analysis identified 89 (5.3%) patients with HER2-altered NSCLCs, comprising 30 (1.8%) with amplification and 59 (3.6%) mutations, and they were compared with 165 control patients. Of the 59 HER2-mutated cases, 52 harbored tyrosine kinase domain (TKD) mutations, primarily HER2 exon 20 insertions. HER2 TKD alterations were associated with younger age, female sex, nonsmoking status, adenocarcinoma with a micropapillary pattern, lung-to-lung metastasis, and poor overall survival. The 33 patients with TKD mutations and 3 with non-TKD point mutations showed incomplete or complete membranous HER2 immunoreactivity (1+ and 2+, 61.07%). Six patients exhibiting amplifications had an IHC score of ≤2+ despite their high copy numbers and concomitantly displayed other actionable EGFR, KRAS, SMARCA4, and other HER2 mutations. These HER2-altered NSCLCs with molecular coalterations showed heterogeneous patterns through HER2 IHC and silver in situ hybridization. Therefore, next-generation sequencing should be used to identify HER2 mutations in patients with NSCLC who present with concomitant alterations. In addition, the above clinicopathological characteristics and HER2 IHC results can be valuable determinants for identifying patients with HER2-altered NSCLC. These insights hold promise for the development of more effective diagnostic and therapeutic strategies for this complex subset of NSCLC 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.

Evaluation of fluorine-18-fluorodeoxyglucose PET/computed tomography and human epithelial growth factor receptor 2 expression in treatment-naive patients with lung adenocarcinoma

OBJECTIVE

Human epithelial growth factor receptor 2 (HER2) is overexpressed in several types of cancers. The correlation between tumor glucose activity and HER2 expression can vary. This study is a retrospective investigation of fluorine-18-fluorodeoxyglucose PET/computed tomography (18F-FDG PET/CT) and HER2 expression status in patients with lung adenocarcinoma.

METHODS

The maximum standard uptake value (SUVmax) of 18F-FDG PET/CT was compared with the HER2 expression status in pretreated patients with lung adenocarcinoma. Moreover, clinicopathological characteristics, including age, gender, smoking, serum tumor markers, tumor location, size, stage and genetic mutation, were also evaluated in groups with different HER2 expressions. Patients' progression-free survival (PFS) and overall survival (OS) were also analyzed.

RESULTS

Ninety-six patients with HER2 expression, including 54 patients with HER2 overexpression and 30 patients without HER2 expression were enrolled in this study. The primary pulmonary lesion was single in all patients, and all lesions were FDG-avid on PET/CT. SUVmax had no significant association with HER2 expression or overexpression in lung adenocarcinoma. Moreover, elevated serum CYFRA211 levels were obviously associated with HER2 expression but not associated with HER2 overexpression. There were no significant differences in other clinicopathological characteristics in groups with different HER2 expressions. Furthermore, multivariate Cox regression analysis revealed that SUVmax, HER2 expression and tumor node metastasis stage were independent predictors of PFS, and SUVmax, CYFRA211 and epidermal growth factor receptor mutation were independent predictors of OS.

CONCLUSION

SUVmax had no significant association with the HER2 expression status in lung adenocarcinoma. 18F-FDG PET/CT and HER2 expression could provide valuable prognostic information for treatment-naive patients with lung adenocarcinoma.

HER2 Aberrations in Non-Small Cell Lung Cancer: From Pathophysiology to Targeted Therapy

While human epidermal growth factor receptor 2 (HER2) aberrations have long been described in patients with non-small cell lung cancer (NSCLC), they have only recently been effectively targeted. Unlike patients with breast cancer, NSCLC patients can harbor either HER2-activating mutations or HER2 amplification coupled with protein overexpression. The latter has also been the case for patients with acquired resistance to epidermal growth factor receptor (EGFR) tyrosine kinase inhibitors (TKIs). As preclinical data continue to accumulate, clinical trials evaluating novel agents that target HER2 have produced promising preliminary results. Here, we review existing data on HER2 aberrations in NSCLC. Starting from HER2 biology in normal and disease processes, we summarize discrepancies in HER2 diagnostic assays between breast cancer and NSCLC. Finally, to dissect the therapeutic implications of HER2-activating mutations versus gene amplification and/or protein overexpression, we present data from prospective clinical trials that have employed distinct classes of agents to target HER2 in patients with NSCLC.

Spotlight on Trastuzumab Deruxtecan (DS-8201,T-DXd) for HER2 Mutation Positive Non-Small Cell Lung Cancer

Human epidermal growth factor receptor 2 (HER2) is a proto-oncogene that, when mutated or overexpressed, plays an important role in oncogenesis. The landscape of HER2-positive breast cancer has changed dramatically over the past 2 decades with the FDA approval of a growing number of agents (antibodies, tyrosine kinase inhibitors, and antibody-drug conjugates) targeting the HER2 receptor. HER2 inhibition has also been approved for HER2-positive gastric cancer. HER2 is amplified in 9% and mutated in 3% of lung cancer. Historically, HER2-targeted therapy for lung cancer with trastuzumab, pertuzumab, and trastuzumab emtansine has failed to demonstrate a survival benefit. Trastuzumab deruxtecan (T-DXd) is a novel antibody–drug conjugate with a tetrapeptide linker, which delivers a topoisomerase I inhibitor with a drug-to-antibody ratio of 7~8. The potency of the active payload, as well as its significant bystander effect, resulted in significant anti-tumor activity. The DESTINY-Lung01 trial evaluated T-DXd in HER2-positive non-squamous non-small cell lung cancer (NSCLC) and reported a progression-free survival of 14 months in HER2-mutated NSCLC, earning its breakthrough designation by the FDA. In this review, we will discuss the structural characteristics, pharmacodynamics, and pharmacokinetics of T-DXd. We will also shed light on the preclinical and ongoing clinical trials of T-DXd along with future directions in the management of HER2 positive 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.

What Is New in Biomarker Testing at Diagnosis of Advanced Non-Squamous Non-Small Cell Lung Carcinoma? Implications for Cytology and Liquid Biopsy

The discovery and clinical validation of biomarkers predictive of the response of non-squamous non-small-cell lung carcinomas (NS-NSCLC) to therapeutic strategies continue to provide new data. The evaluation of novel treatments is based on molecular analyses aimed at determining their efficacy. These tests are increasing in number, but the tissue specimens are smaller and smaller and/or can have few tumor cells. Indeed, in addition to tissue samples, complementary cytological and/or blood samples can also give access to these biomarkers. To date, it is recommended and necessary to look for the status of five genomic molecular biomarkers (EGFR, ALK, ROS1, BRAFV600, NTRK) and of a protein biomarker (PD-L1). However, the short- and more or less long-term emergence of new targeted treatments of genomic alterations on RET and MET, but also on others’ genomic alteration, notably on KRAS, HER2, NRG1, SMARCA4, and NUT, have made cellular and blood samples essential for molecular testing. The aim of this review is to present the interest in using cytological and/or liquid biopsies as complementary biological material, or as an alternative to tissue specimens, for detection at diagnosis of new predictive biomarkers of NS-NSCLC.

[ISH-based HER2 diagnostics]

A prerequisite for all HER2 directed therapies is the demonstration of HER2 receptor protein overexpression and/or gene amplification by in situ hybridization (ISH). ASCO and CAP have published several HER2 test guidelines over the past 15 years for both breast and gastric cancer. The latest version for breast cancer (2018) focuses on special issues of ISH related to the definitions of special diagnostic groups (1-5). The guidelines for gastroesophageal adenocarcinoma (2017), essentially based on ToGA trial data, are now also being used for other tumors such as pancreas, gallbladder, and non-small-cell lung cancer. For colorectal cancer, a modified testing procedure has been proposed. Recently, besides overexpression and amplification, a third type of HER gene alteration, namely mutation, has gained much interest. Next-generation sequencing (NGS) allows detection of both amplification and mutation of the HER2 gene providing new options of therapy especially in the case of activating mutations.

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.

ISH-based HER2 diagnostics

A prerequisite for all HER2 directed therapies is the demonstration of HER2 receptor protein overexpression and/or gene amplification by in situ hybridization (ISH). ASCO and CAP have published several HER2 test guidelines over the past 15 years for both breast and gastric cancer. The latest version for breast cancer (2018) focuses on special issues of ISH related to the definitions of special diagnostic groups (1-5). The guidelines for gastroesophageal adenocarcinoma (2017), essentially based on ToGA trial data, are now also being used for other tumors such as pancreas, gallbladder, and non-small-cell lung cancer. For colorectal cancer, a modified testing procedure has been proposed. Recently, besides overexpression and amplification, a third type of HER gene alteration, namely mutation, has gained much interest. Next-generation sequencing (NGS) allows detection of both amplification and mutation of the HER2 gene providing new options of therapy especially in the case of activating mutations.

HER2 Mutated and Nonmutated Non-small Cell Lung Carcinomas Can Harbor Heterogeneous HER2 Gene Amplification and HER2 Protein Expression

Molecular analyses have become mandatory for treatment choices in patients with advanced non-small cell lung cancers (NSCLC). Among them, HER2 gene mutation, HER2 gene amplification, and HER2 protein expression consist in potential targets of various treatments. Tumor heterogeneity and overlapping of molecular alterations may cause dilemmas in treatment choices but to date there are few that reported about HER2 with discrepant data. We led a retrospective study evaluating HER2 protein expression and HER2 gene/chromosome 17 copy number variations across different tumor areas and samples from patients with advanced NSCLC harboring HER2 gene mutations and other oncogenic mutations. Among patients with HER2-mutated (10 patients) and nonmutated lung adenocarcinomas (10 patients), we observed frequent heterogeneous HER2 protein expression with no correlation with HER2 gene copy number variations. HER2 gene amplification was observed in 6 patients (3 HER2-mutated and 3 HER2-nonmutated), but with intrasample heterogeneity in 2 cases and intersample heterogeneity in another case. Our small case series emphasizes the potential overlapping and spatial heterogeneity of HER2 alterations in NSCLC, which must be taken into account as a limitation in building predictive strategies accompanying the development of anti-HER2 therapeutic strategies in patients with advanced NSCLC.

Impact of HER2 expression on EGFR-TKI treatment outcomes in lung tumors harboring EGFR mutations: A HER2-CS study subset analysis

OBJECTIVES

Epidermal growth factor receptor (EGFR)-tyrosine kinase inhibitors (TKIs) are standard treatment for EGFR-mutated non-small-cell lung carcinoma (NSCLC); however, a biomarker to predict their efficacy has not been established. Although human epidermal growth factor receptor-2 (HER2) aberrations constitute a potential mechanism for acquired resistance to EGFR-TKIs, the impact of HER2 on EGFR-TKI treatment outcomes has not been systematically evaluated. In this post-hoc subgroup study, we examined the impact of HER2 on the effect of EGFR-TKIs in patients with NSCLC harboring EGFR mutations.

MATERIALS AND METHODS

Of 1126 patients with NSCLC enrolled into a prospective cohort study (HER2-CS study), we analyzed data of 356 (32 %) patients with EGFR-mutant tumors. HER2 protein expression levels were determined by immunohistochemistry (IHC) with the gastric cancer criteria. Patients were divided either to an HER2-P group (HER2-IHC2+/3+) or an HER2-N group (HER2-IHC0/1+). We primarily assessed differences in the time-to-treatment failure (TTF) of EGFR-TKI between the groups.

RESULTS

The HER2 scoring was as follows: IHC0 (n = 76, 21 %), IHC1+ (n = 199, 56 %), IHC2+ (n = 72, 20 %), and IHC3+ (n = 9, 3 %). The patients' demographics were similar in the HER2-P and HER2-N groups. The HER2-P group showed a significantly shorter EGFR-TKI TTF than the HER2-N group (hazard ratio [HR]: 1.657, 95 % confidence interval [CI]: 1.076-2.552; median: 13.3 vs. 19.1 months). The magnitude of the negative impact of TTF was especially dependent on performance status (PS). HER2 expression significantly deteriorated the TTF in the subgroup with PS 2 (HR: 5.497, 95 % CI: 1.510-20.02), but not in that with better PS (HR: 1.437, 95 % CI: 0.899-2.298) (p_interaction = 0.015).

CONCLUSION

In the current cohort, HER2 protein expression in EGFR-mutant NSCLC may have a negative impact on the effect of EGFR-TKIs, the effect of which was PS dependent.