Mutation Variants and Co-Mutations as Genomic Modifiers of Response to Afatinib in HER2-Mutant Lung Adenocarcinoma

Prevalence and treatment of human epidermal growth factor receptor 2-altered non-small cell lung cancer: a retrospective analysis and systematic literature review

Human epidermal growth factor receptor 2 (HER2) is known for its oncogenic activities in diverse cancers, including non-small cell lung cancer (NSCLC). However, the prevalence of HER2 alterations in Malaysian NSCLC patients remains unreported. This study examined the prevalence and characteristics of HER2 mutations and amplification in a Malaysian cohort. Additionally, a systematic review was conducted to evaluate the global prevalence of HER2 alterations in NSCLC, as well as the efficacy of HER2-targeted therapies observed in clinical trials. NSCLC tumour samples received from October 2019 to December 2022 for next-generation sequencing diagnostics were included in the retrospective analysis. In this patient cohort, HER2 alteration was present in 5.8% of patients; 3.9% had HER2 mutations, 1.5% had HER2 amplifications and 0.4% were both HER2-mutated and amplified. HER2 exon 20 insertions were the most common HER2 variants, detected in 47/59 (79.7%) of HER2-mutated patients. Among cases with HER2 exon 20 insertions, the Y772_A775dup variant was found in 34 patient samples. HER2-mutated patients were significantly younger than non-HER2-mutants (61 versus 64 years old; p = 0.046) and were inclined to be female and never-smokers, albeit not statistically significant. Patients with HER2 amplification were more likely to have progressed post-tyrosine kinase inhibitor therapy (p = 0.015). The systematic review highlighted a global variation in the prevalence of HER2 alterations in NSCLC, ranging from 0.3% to 9.1% for mutations and 0.2% to 19% for amplification. Finally, phase II clinical trials involving HER2-altered NSCLC patients demonstrated promising treatment outcomes with trastuzumab deruxtecan, trastuzumab emtansine, pyrotinib, pyrotinib + apatinib and trastuzumab + pertuzumab + docetaxel. In conclusion, the prevalence of HER2 alteration among Malaysian NSCLC patients falls within the global range. A systematic review of clinical trials revealed promising treatment outcomes and Malaysian NSCLC patients with HER2 alterations are anticipated to similarly benefit from HER2-targeted therapies.

A-to-I RNA co-editing predicts clinical outcomes and is associated with immune cells infiltration in hepatocellular carcinoma

Aberrant RNA editing has emerged as a pivotal factor in the pathogenesis of hepatocellular carcinoma (HCC), but the impact of RNA co-editing within HCC remains underexplored. We used a multi-step algorithm to construct an RNA co-editing network in HCC, and found that HCC-related RNA editings are predominantly centralized within the network. Furthermore, five pairs of risk RNA co-editing events were significantly correlated with the overall survival in HCC. Based on presence of risk RNA co-editings resulted in the categorization of HCC patients into high-risk and low-risk groups. Disparities in immune cell infiltrations were observed between the two groups, with the high-risk group exhibiting a greater abundance of exhausted T cells. Additionally, seven genes associated with risk RNA co-editing pairs were identified, whose expression effectively differentiates HCC tumor samples from normal ones. Our research offers an innovative perspective on the etiology and potential therapeutics for HCC.

HER2-Altered Non-Small Cell Lung Cancer: A Journey from Current Approaches to Emerging Strategies

For patients diagnosed with advanced HER2-altered non-small cell lung cancer (NSCLC), the current standard of care is represented by a platinum-pemetrexed-based chemotherapy, eventually in combination with immunotherapy. Different pan-HER tyrosine kinase inhibitors have been evaluated in limited phase II trials, yielding generally unsatisfactory outcomes, although certain genotypes demonstrated some clinical benefit. Conversely, antibody-drug conjugates (ADCs) targeting HER2, particularly trastuzumab-deruxtecan, have shown promising results against HER2-mutant disease, including a great intracranial activity in patients with brain metastasis. Based on the results obtained from DESTINY-Lung01 and DESTINY-Lung02 trials, trastuzumab deruxtecan received regulatory approval as the first targeted therapy for pre-treated, HER2-mutant, advanced NSCLC patients. More recently, the Food and Drug Administration (FDA) granted the accelerated approval of trastuzumab deruxtecan for advanced, pre-treated HER2-positive solid tumours with no other treatment options. In this scenario, emerging evidence is increasingly pointing towards the exploration of combination regimens with synergistic effects in the advanced disease. In this review, we provide a detailed summary of current approaches and emerging strategies in the management of HER2-altered NSCLC, also focusing on unmet needs, including the treatment of patients with brain metastases.

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.

Progress of PD-1/PD-L1 inhibitor combination therapy in immune treatment for HER2-positive tumors

BACKGROUND

Patients with HER2-positive cancers often face a poor prognosis, and treatment regimens containing anti-HER2 have become the first-line treatment options for breast and gastric cancers. However, these approaches are faced with significant challenges in terms of drug resistance. Hence, it is crucial to explore precise treatment strategies aimed at improving survival outcomes.

ADVANCEMENTS IN TREATMENT

Over the past few years, there has been rapid advancement in the realm of tumor therapy, particularly with the swift progress of immune checkpoint inhibitors, including PD-1/PD-L1 inhibitors. They exert anti-tumor effects by disrupting immune-suppressive factors within the tumor microenvironment. However, monotherapy with PD-1/PD-L1 inhibitors has several limitations. Consequently, numerous studies have explored combinatorial immunotherapeutic strategies and demonstrated highly promising avenues of development.

OBJECTIVE

This article aims to review the clinical trials investigating PD-1/PD-L1 inhibitor combination therapy for HER2-positive tumors. Additionally, it provides a summary of ongoing trials evaluating the efficacy and safety of these combined treatments, with the intention of furnishing valuable insights for the clinical management of HER2-positive cancer.

CONCLUSION

Combinatorial immunotherapeutic strategies involving PD-1/PD-L1 inhibitors hold considerable promise in the treatment of HER2-positive tumors. Continued research efforts and clinical trials are warranted to elucidate optimal treatment regimens that maximize therapeutic benefits while minimizing adverse effects.

Mechanisms of resistance to targeted therapy and immunotherapy in non-small cell lung cancer: promising strategies to overcoming challenges

Resistance to targeted therapy and immunotherapy in non-small cell lung cancer (NSCLC) is a significant challenge in the treatment of this disease. The mechanisms of resistance are multifactorial and include molecular target alterations and activation of alternative pathways, tumor heterogeneity and tumor microenvironment change, immune evasion, and immunosuppression. Promising strategies for overcoming resistance include the development of combination therapies, understanding the resistance mechanisms to better use novel drug targets, the identification of biomarkers, the modulation of the tumor microenvironment and so on. Ongoing research into the mechanisms of resistance and the development of new therapeutic approaches hold great promise for improving outcomes for patients with NSCLC. Here, we summarize diverse mechanisms driving resistance to targeted therapy and immunotherapy in NSCLC and the latest potential and promising strategies to overcome the resistance to help patients who suffer from NSCLC.

Co-expression of IL-21-Enhanced NKG2D CAR-NK cell therapy for lung cancer

BACKGROUND

Adoptive cell therapy has achieved great success in treating hematological malignancies. However, the production of chimeric antigen receptor T (CAR-T) cell therapy still faces various difficulties. Natural killer (NK)-92 is a continuously expandable cell line and provides a promising alternative for patient's own immune cells.

METHODS

We established CAR-NK cells by co-expressing natural killer group 2 member D (NKG2D) and IL-21, and evaluated the efficacy of NKG2D-IL-21 CAR-NK cells in treating lung cancer in vitro and in vivo.

RESULTS

Our data suggested that the expression of IL-21 effectively increased the cytotoxicity of NKG2D CAR-NK cells against lung cancer cells in a dose-dependent manner and suppressed tumor growth in vitro and in vivo. In addition, the proliferation of NKG2D-IL-21 CAR-NK cells were enhanced while the apoptosis and exhaustion of these cells were suppressed. Mechanistically, IL-21-mediated NKG2D CAR-NK cells function by activating AKT signaling pathway.

CONCLUSION

Our findings provide a novel option for treating lung cancer using NKG2D-IL-21 CAR-NK cell therapy.

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.

Efficacy and safety of a pyrotinib-based regimen in non-small cell lung cancer patients harboring HER2 alterations: A real-world retrospective study

BACKGROUND

Pyrotinib, a novel irreversible pan-HER tyrosine kinase inhibitor, has been approved for the treatment of HER2-positive metastatic breast cancer in China. The aim of this study was to evaluate the efficacy and safety of pyrotinib in advanced nonsmall cell lung cancer (NSCLC) patients with HER2 alterations in real-world practice.

MATERIALS AND METHODS

A retrospective analysis of advanced NSCLC with HER2 mutations or amplifications who received pyrotinib-based treatment at the Qilu Hospital in Shandong University was performed. The primary end points were objective response rate and safety. The secondary end points were progression-free survival, disease control rate, and overall survival.

RESULTS

Twenty three eligible patients from a single center were enrolled between June 2019 and March 2023; among them, 21 had HER2 mutation and two harbored HER2 amplification. Evaluation of the efficacy in 21 patients revealed an objective response rate of 28.6% (6/21; 95% confidence interval [CI]: 7.5%-49.6%) and disease control rate of 85.7% (18/21). The median progression-free survival and overall survival were 7.7 months (95% CI: 6.07-9.33) and 20.8 months (95% CI: 8.42-33.18), respectively. The most common adverse events (AEs) included diarrhea (n = 14, 60.9%), nausea (n = 5, 21.7%), and liver dysfunction (n = 5, 21.7%). Seven patients (7/23, 30.4%) had grade 3-4 AE; no grade 5 AE was observed. Furthermore, one patient (1/23, 4.3%) experienced dose withdrawal and two (2/23, 8.7%) presented with dose reduction symptoms.

CONCLUSION

Pyrotinib-based therapy showed promising antitumor activity and acceptable safety in advanced NSCLC patients with HER2 alterations.

Immunotherapy as a later-line option for HER2-altered advanced non-small-cell lung cancer: taxane might be a favorable partner

Aim: To assess the effectiveness of different types of taxanes, including nab-paclitaxel, paclitaxel and docetaxel, and further compare the effectiveness of taxane-based chemotherapy, taxane-based chemotherapy plus angiogenesis inhibitors or taxane-based chemotherapy plus immune checkpoint inhibitors in HER2-altered non-small-cell lung cancer in the second- or third-line setting. Materials & methods: A total of 52 patients were included in the study. Progression-free survival was compared between subgroups. Results: A clinically meaningful improvement in progression-free survival was observed among patients in the nab-paclitaxel group compared with the docetaxel group. Taxane-based chemotherapy plus immune checkpoint inhibitors achieved longer progression-free survival than taxane-based chemotherapy. There was no difference between taxane-based chemotherapy plus immune checkpoint inhibitors and taxane-based chemotherapy plus angiogenesis inhibitors. Conclusion: Nab-paclitaxel appears to be a reasonable alternative to docetaxel. Chemotherapy plus immune checkpoint inhibitors might yield more survival benefits than chemotherapy alone.

Development of a Somatic Variant Registry in a National Cancer Center: towards Molecular Real World Data preparedness

The Biomedical Research field is currently advancing to develop Clinical Trials and translational projects based on Real World Evidence. To make this transition feasible, clinical centers need to work toward Data Accessibility and Interoperability. This task is particularly challenging when applied to Genomics, that entered in routinary screening in the last years via mostly amplicon-based Next-Generation Sequencing panels. Said experiments produce up to hundreds of features per patient, and their summarized results are often stored in static clinical reports, making critical information inaccessible to automated access and Federated Search consortia. In this study, we present a reanalysis of 4620 solid tumor sequencing samples in five different histology settings. Furthermore, we describe all the Bioinformatics and Data Engineering processes that were put in place in order to create a Somatic Variant Registry able to deal with the large biotechnological variability of routinary Genomics Profiling.

A review of recent advances in the novel therapeutic targets and immunotherapy for lung cancer

Lung cancer is amongst the most pervasive malignancies having high mortality rates. It is broadly grouped into non-small-cell lung cancer (NSCLC) and small-cell lung cancer (SCLC). The concept of personalized medicine has overshadowed the conventional chemotherapy given to all patients with lung cancer. The targeted therapy is given to a particular population having specific mutations to help in the better management of lung cancer. The targeting pathways for NSCLC include the epidermal growth factor receptor, vascular endothelial growth factor receptor, MET (Mesenchymal epithelial transition factor) oncogene, Kirsten rat sarcoma viral oncogene (KRAS), and anaplastic lymphoma kinase (ALK). SCLC targeting pathway includes Poly (ADP-ribose) polymerases (PARP) inhibitors, checkpoint kinase 1 (CHK 1) pathway, WEE1 pathway, Ataxia Telangiectasia and Rad3-related (ATR)/Ataxia telangiectasia mutated (ATM), and Delta-like canonical Notch ligand 3 (DLL-Immune checkpoint inhibitors like programmed cell death protein 1 (PD-1)/ programmed death-ligand 1 (PD-L1) inhibitors and Cytotoxic T-lymphocyte-associated antigen-4 (CTLA4) blockade are also utilized in the management of lung cancer. Many of the targeted therapies are still under development and require clinical trials to establish their safety and efficacy. This review summarizes the mechanism of molecular targets and immune-mediated targets, recently approved drugs, and their clinical trials for lung cancer.

Survival benefit and biomarker analysis of pyrotinib or pyrotinib plus capecitabine for patients with HER2-positive metastatic breast cancer: a pooled analysis of two phase I studies

BACKGROUND

Pyrotinib, a novel irreversible tyrosine kinase inhibitor (TKI), has demonstrated promising antitumor activity to improve the overall response rate and progression-free survival (PFS) in patients with HER2-positive metastatic breast cancer (MBC). However, the survival data of pyrotinib or pyrotinib plus capecitabine in HER2-positive MBC remains scarce. Thus, we summarized the updated individual patient data from the phase I trials of pyrotinib or pyrotinib plus capecitabine, to provide a cumulative assessment on long-term outcomes and associated biomarker analysis of irreversible TKIs in HER2-positive MBC patients.

METHODS

We performed a pooled analysis of the phase I trials for pyrotinib or pyrotinib plus capecitabine based on the updated survival data from individual patients. Next-generation sequencing was performed on circulating tumor DNA for predictive biomarkers.

RESULTS

A total of 66 patients were enrolled, including 38 patients from the phase Ib trial for pyrotinib and 28 patients from the phase Ic trial for pyrotinib plus capecitabine. The median follow-up duration was 84.2 months (95% CI: 74.7-93.7 months). The estimated median PFS in the entire cohort was 9.2 months (95% CI: 5.4-12.9 months) and median OS was 31.0 months (95% CI: 16.5-45.5 months). The median PFS was 8.2 months in the pyrotinib monotherapy cohort and 22.1 months in the pyrotinib plus capecitabine group, while the median OS was 27.1 months in the pyrotinib monotherapy group and 37.4 months in the pyrotinib plus capecitabine group. Biomarker analysis suggested that the patients harbored concomitant mutations from multiple pathways in HER2-related signaling network (HER2 bypass signaling pathways, PI3K/Akt/mTOR pathway and TP53) were observed with significantly poorer PFS and OS when compared to those with none or one genetic alteration (median PFS, 7.3 vs. 26.1 months, P = 0.003; median OS, 25.1 vs. 48.0 months, P = 0.013).

CONCLUSIONS

The updated survival results based on individual patient data from the phase I trials of pyrotinib-based regimen revealed promising PFS and OS in HER2-positive MBC. Concomitant mutations from multiple pathways in HER2-related signaling network may be a potential efficacy and prognosis biomarker for pyrotinib in HER2-positive MBC.

TRIAL REGISTRATION

ClinicalTrials.gov. (NCT01937689, NCT02361112).

Molecular pathways, resistance mechanisms and targeted interventions in non-small-cell lung cancer

Lung cancer is the leading cause of cancer-related mortality worldwide. The discovery of tyrosine kinase inhibitors effectively targeting EGFR mutations in lung cancer patients in 2004 represented the beginning of the precision medicine era for this refractory disease. This great progress benefits from the identification of driver gene mutations, and after that, conventional and new technologies such as NGS further illustrated part of the complex molecular pathways of NSCLC. More targetable driver gene mutation identification in NSCLC patients greatly promoted the development of targeted therapy and provided great help for patient outcomes including significantly improved survival time and quality of life. Herein, we review the literature and ongoing clinical trials of NSCLC targeted therapy to address the molecular pathways and targeted intervention progress in NSCLC. In addition, the mutations in EGFR gene, ALK rearrangements, and KRAS mutations in the main sections, and the less common molecular alterations in MET, HER2, BRAF, ROS1, RET, and NTRK are discussed. The main resistance mechanisms of each targeted oncogene are highlighted to demonstrate the current dilemma of targeted therapy in NSCLC. Moreover, we discuss potential therapies to overcome the challenges of drug resistance. In this review, we manage to display the current landscape of targetable therapeutic patterns in NSCLC in this era of precision medicine.

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.

Targeting the EGF receptor family in non-small cell lung cancer-increased complexity and future perspectives

Lung cancer remains the leading cause of cancer-associated mortality worldwide, but with the emergence of oncogene targeted therapies, treatment options have tremendously improved. Owing to their biological relevance, members of the ERBB receptor family, including the EGF receptor (EGFR), HER2, HER3 and HER4, are among the best studied oncogenic drivers. Activating EGFR mutations are frequently observed in non-small cell lung cancer (NSCLC), and small molecule tyrosine kinase inhibitors (TKIs) are the established first line treatment option for patients whose tumors bear "typical/classical" EGFR mutations (exon 19 deletions, L858R point mutations). Additionally, new TKIs are rapidly evolving with better efficacy to overcome primary and secondary treatment resistance (e.g., that due to T790M or C797S resistance mutations). Some atypical EGFR mutations, such as the most frequent exon 20 insertions, exhibit relative resistance to earlier generation TKIs through steric hindrance. In this subgroup, newer TKIs, such as mobocertinib and the bi-specific antibody amivantamab have recently been approved, whereas less frequent atypical EGFR mutations remain understudied. In contrast to EGFR, HER2 has long remained a challenging target, but better structural understanding has led to the development of newer generations of TKIs. The recent FDA approval of the antibody-drug conjugate trastuzumab-deruxtecan for pretreated patients with HER2 mutant NSCLC has been an important therapeutic breakthrough. HER3 and HER4 also exert oncogenic potential, and targeted treatment approaches are being developed, particularly for HER3. Overall, strategies to inhibit the oncogenic function of ERBB receptors in NSCLC are currently evolving at an unprecedented pace; therefore, this review summarizes current treatment standards and discusses the outlook for future developments.

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.

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.

Phase II Study of Afatinib in Patients With Tumors With Human Epidermal Growth Factor Receptor 2-Activating Mutations: Results From the National Cancer Institute-Molecular Analysis for Therapy Choice ECOG-ACRIN Trial (EAY131) Subprotocol EAY131-B

PURPOSE

National Cancer Institute-Molecular Analysis for Therapy Choice is a multicohort trial that assigns patients with advanced cancers to targeted therapies on the basis of central tumor genomic testing. Arm B evaluated afatinib, an ErbB family tyrosine kinase inhibitor, in patients with ERBB2-activating mutations.

METHODS

Eligible patients had selected ERBB2 single-nucleotide variants or insertions/deletions detected by the National Cancer Institute-Molecular Analysis for Therapy Choice next-generation sequencing assay. Patients had performance status ≤ 1, left ventricular ejection fraction > 50%, grade ≤ 1 diarrhea, and no prior human epidermal growth factor receptor 2 (HER2) therapy. Patients received afatinib 40 mg once daily in 28-day cycles. The primary end point was objective response rate (ORR). Secondary end points were 6-month progression-free survival, overall survival, toxicity, and molecular correlates.

RESULTS

A total of 59 patients were assigned and 40 were enrolled. The median age was 62 years, 78% were female, 68% had performance status = 1, and 58% had received > 3 prior therapies. The confirmed ORR was 2.7% (n = 1 of 37; 90% CI, 0.14 to 12.2), and 6-month progression-free survival was 12.0% (90% CI, 5.6 to 25.8). A confirmed partial response occurred in a patient with adenocarcinoma of extra-mammary Paget disease of skin who progressed after cycle 6. Two unconfirmed partial responses were observed (low-grade serous gynecological tract and estrogen receptor-positive/HER2-negative immunohistochemistry breast ductal carcinoma). Of 12 patients with breast cancer, 1 additional patient with lobular carcinoma (estrogen receptor-positive/HER2 fluorescent in situ hybridization) had a 51% reduction in target lesions but progressed because of a new lesion at cycle 6. The most common (> 20%) treatment-related adverse events were diarrhea (68%), mucositis (43%), fatigue (40%), acneiform rash (30%), dehydration (27%), vomiting (27%), nausea (27%), anemia (27%), and anorexia (22%). Four patients (11%) discontinued because of adverse events.

CONCLUSION

Although afatinib did not meet the prespecified threshold for antitumor activity in this heavily pretreated cohort, the response in a rare tumor type is notable. The safety profile of afatinib was consistent with prior studies.

Characterization of ERBB2 (HER2) Alterations in Metastatic Non-small Cell Lung Cancer and Comparison of Outcomes of Different Trastuzumab-based Regimens

INTRODUCTION

About 3%-5% of mNSCLC have ERBB2 (HER2) alterations, but currently, there are no FDA-approved targeted therapies for this indication. We compared treatment response between trastuzumab-based and non-targeted regimens in ERBB2-mutant mNSCLC.

METHODS

This retrospective, single-institution study included patients with mNSCLC with ERBB2 alterations identified by next-generation sequencing. Best overall response was determined using Response Evaluation Criteria in Solid Tumors 1.1.

RESULTS

We identified 3 groups of patients: ERBB2-mutant/EGFR-wildtype mNSCLC (n = 33), ERBB2-amplified/EGFR-wildtype mNSCLC without concurrent ERBB2 mutations (n = 6), and ERBB2-altered/EGFR-mutant mNSCLC (n = 8). Observed mutations included A775_G776insYVMA (n = 23), Gly778_Pro780dup (n = 4), Ser310Phe (n = 3), and others (n = 5). Among the 33 with ERBB2-mutant/EGFR-wildtype mNSCLC, those with and without A775_G776insYVMA had significantly different median overall survival (OS) of 17.7 and 52.9 months, respectively (Cox regression multivariable HR: 5.03, 95% CI: 1.37-18.51, P = .02). In those with mNSCLC with A775_G776insYVMA, trastuzumab-based therapies were associated with greater OS (20.3 vs. 9.8 months; multivariable HR: 0.19, 95% CI: 0.04-0.87, P = .032). Objective response and disease control rates (median tumor size change) in the 33 patients with ERBB2-mutant/EGFR-wildtype mNSCLC were 40.0% and 80.0% (-35.8%), respectively, for patients treated with trastuzumab deruxtecan; 0% and 30.0% (-5.2%) for trastuzumab emtansine; and 7.1% and 50.0% (-13.0%) for trastuzumab/chemotherapy combinations.

CONCLUSION

In ERBB2-mutant/EGFR-wildtype mNSCLC, while most trastuzumab-based regimens had modest activity in this real-world analysis, trastuzumab deruxtecan had highest response rates and best tumor size reduction. Receipt of any trastuzumab-based regimen was associated with greater OS with A775_G776insYVMA. There remains an unmet need for approved targeted therapies for ERBB2-mutant/EGFR-wildtype NSCLC.

Associations of HER2 Mutation With Immune-Related Features and Immunotherapy Outcomes in Solid Tumors

Background

HER2 is one of the most extensively studied oncogenes in solid tumors. However, the association between tumor microenvironment (TME) and HER2 mutation remains elusive, and there are no specific therapies for HER2-mutated tumors. Immune checkpoint inhibitors (ICIs) have been approved for some tumor subgroups that lack targeted therapies, while their effects are still unclear in HER2-mutated tumors. We examined whether HER2 mutation impacts treatment outcomes of ICIs in solid tumors via its association with anticancer immunity.

Methods

Multi-omics data of solid tumors from The Cancer Genome Atlas (TCGA), the Asian Cancer Research Group and the Affiliated Hospital of Jiangsu University were used to analyze the association between HER2 mutations and tumor features. Data of patients with multiple microsatellite-stable solid tumors, who were treated by ICIs including antibodies against programmed cell death-1 (PD-1), programmed cell death ligand-1 (PD-L1), or cytotoxic T lymphocyte-associated protein 4 (CTLA-4) in eight studies, were collected to investigate the effects of HER2 mutations on immunotherapy outcomes.

Results

The mutation rate of HER2 varied in solid tumors of TCGA, with an overall incidence of 3.13%, ranged from 0.39% to 12.2%. Concurrent HER2 mutations and amplifications were rare (0.26%). HER2 mutation was not associated with HER2 protein expression but was positively associated with microsatellite instability, tumor mutation and neoantigen burdens, infiltrating antitumor immune cells, and signal activities of antitumor immunity. Of 321 ICI-treated patients, 18 carried HER2 mutations (5.6%) and showed improved objective response rates compared with those with HER2 wild-type (44.4% vs. 25.7%, p=0.081), especially in the anti-PD-1/anti-PD-L1 subgroup (62.5% vs. 28.4%, p=0.04). Heterogeneity was observed among tumor types. Patients with HER2 mutations also had superior overall survival than those with HER2 wild-type (HR=0.47, 95%CI: 0.23-0.97, p=0.04), especially in the presence of co-mutations in ABCA1 (HR = 0.23, 95% CI: 0.07-0.73, p=0.013), CELSR1 (HR = 0.24, 95% CI: 0.08-0.77, p=0.016), LRP2 (HR = 0.24, 95% CI: 0.07-0.74, p=0.014), or PKHD1L1 (HR = 0.2, 95% CI: 0.05-0.8, p=0.023).

Conclusions

HER2 mutations may improve the TME to favor immunotherapy. A prospective basket trial is needed to further investigate the impacts of HER2 mutations on immunotherapy outcomes in solid tumors.

Response of Leptomeningeal Metastasis of Breast Cancer With a HER2/neu Activating Variant to Tucatinib: A Case Report

Metastatic breast cancer demonstrates HER2/neu amplification approximately 15% of the time. However, HER2 mutations, which often stimulate tumor growth, occur in only 3% to 5% of patients, and are seen more frequently in metastatic versus primary tumors. They are more frequent in lobular carcinoma, including triple-negative lobular cancer. Many of these variants are resistant to trastuzumab and lapatinib. However, neratinib can be efficacious, and recent data suggest that antibody-drug conjugates (ADCs) such as ado-trastuzumab emtansine (T-DM1) and trastuzumab deruxtecan may also be helpful. Laboratory and clinical data raise the possibility that simultaneous treatment with ADCs plus neratinib may be even more efficacious. Tucatinib, which has demonstrated significant activity in the central nervous system, has also been shown in vitro to be active against a number of these HER2 variants. This report describes a patient with metastatic estrogen receptor-positive, HER2-nonamplified breast cancer with an activating HER2 mutation whose tumor became resistant to neratinib as well as capecitabine, but whose subsequent leptomeningeal disease had a dramatically successful response to tucatinib plus capecitabine. As the frequency of HER2 mutations increases during the evolution of metastatic breast cancer, it is important to obtain genomic evaluation on these tumors with either repeat tissue or liquid biopsy as they progress over time.

Cancer mutation profiles predict ICIs efficacy in patients with non-small cell lung cancer

Although immune checkpoint inhibitors (ICIs) have produced remarkable responses in non-small cell lung cancer (NSCLC) patients, receivers still have a relatively low response rate. Initial response assessment by conventional imaging and evaluation criteria is often unable to identify whether patients can achieve durable clinical benefit from ICIs. Overall, there are sparse effective biomarkers identified to screen NSCLC patients responding to this therapy. A lot of studies have reported that patients with specific gene mutations may benefit from or resist to immunotherapy. However, the single gene mutation may be not effective enough to predict the benefit from immunotherapy for patients. With the advancement in sequencing technology, further studies indicate that many mutations often co-occur and suggest a drastic transformation of tumour microenvironment phenotype. Moreover, co-mutation events have been reported to synergise to activate or suppress signalling pathways of anti-tumour immune response, which also indicates a potential target for combining intervention. Thus, the different mutation profile (especially co-mutation) of patients may be an important concern for predicting or promoting the efficacy of ICIs. However, there is a lack of comprehensive knowledge of this field until now. Therefore, in this study, we reviewed and elaborated the value of cancer mutation profile in predicting the efficacy of immunotherapy and analysed the underlying mechanisms, to provide an alternative way for screening dominant groups, and thereby, optimising individualised therapy for NSCLC patients.

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.

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.

First-line immunotherapy or angiogenesis inhibitor plus chemotherapy for HER2-altered NSCLC: a retrospective real-world POLISH study

Background:

There have been no comprehensive large-scale studies that have evaluated the benefits of chemotherapy-based regimens in addressing HER2-altered advanced non-small-cell lung cancer (NSCLC) in a first-line setting. Data on HER2 alteration subtypes and concomitant alterations are also limited. Accordingly, our retrospective, real-world POLISH study assesses the efficacy of first-line chemotherapy alone (C) as well as combinations with immune checkpoint inhibitors (C + I) or angiogenesis inhibitors (C + A) for HER2-altered NSCLC; molecular features are also reported.

Methods:

HER2-altered NSCLC patients who received a first-line treatment between November 2015 and September 2021 were screened. Patients treated with C, C + I, or C + A were included in our final efficacy analysis. Progression-free survival (PFS) was compared between the subgroups. A Kyoto Encyclopedia of Genes and Genomes (KEGG) analysis was performed to evaluate concomitant alterations.

Results:

A total of 293 patients were screened, with an identification of HER2 amplification and 37 distinct HER2 mutations, and 210 cases treated with C, C + I, or C + A were ultimately included. C + A achieved longer PFS than C (5.63 vs 4.03 months, hazard ratio: 0.64, 95% confidence interval [CI]: 0.46–0.88, p = 0.006). C + I did not improve median PFS compared to C + A or C (both p > 0.05), despite the programmed cell death ligand-1 (PD-L1) expression or tumor mutational burden. KEGG analysis revealed that concomitant upregulation of PI3 K/AKT pathway signaling was common in HER2-altered NSCLC.

Conclusion:

Chemotherapy plus angiogenesis inhibitors may yield a greater survival benefit than chemotherapy alone in a first-line setting for HER2-altered NSCLC, whereas an immune-based combination therapy may not be superior to a sole chemotherapy regimen. Activation of PI3 K/AKT signaling may mediate immunosuppression in HER2-altered NSCLC.

Poziotinib in Non-Small-Cell Lung Cancer Harboring HER2 Exon 20 Insertion Mutations After Prior Therapies: ZENITH20-2 Trial

PURPOSE

Insertion mutations in Erb-b2 receptor tyrosine kinase 2 gene (ERBB2 or HER2) exon 20 occur in 2%-5% of non-small-cell lung cancers (NSCLCs) and function as an oncogenic driver. Poziotinib, a tyrosine kinase inhibitor, was evaluated in previously treated patients with NSCLC with HER2 exon 20 insertions.

METHODS

ZENITH20, a multicenter, multicohort, open-label phase II study, evaluated poziotinib in patients with advanced or metastatic NSCLC. In cohort 2, patients received poziotinib (16 mg) once daily. The primary end point was objective response rate evaluated by independent review committee (RECIST v1.1); secondary outcome measures were disease control rate, duration of response, progression-free survival, and safety and tolerability. Quality of life was assessed.

RESULTS

Between October 2017 and March 2021, 90 patients with a median of two prior lines of therapy (range, 1-6) were treated. With a median follow-up of 9.0 months, objective response rate was 27.8% (95% CI, 18.9 to 38.2); 25 of 90 patients achieved a partial response. Disease control rate was 70.0% (95% CI, 59.4 to 79.2). Most patients (74%) had tumor reduction (median reduction 22%). Median progression-free survival was 5.5 months (95% CI, 3.9 to 5.8); median duration of response was 5.1 months (95% CI, 4.2 to 5.5). Clinical benefit was seen regardless of lines and types of prior therapy, presence of central nervous system metastasis, and types of HER2 mutations. Grade 3 or higher treatment-related adverse events included rash (48.9%), diarrhea (25.6%), and stomatitis (24.4%). Most patients had poziotinib dose reductions (76.7%), with median relative dose intensity of 71.5%. Permanent treatment discontinuation because of treatment-related adverse events occurred in 13.3% of patients.

CONCLUSION

Poziotinib demonstrates antitumor activity in previously treated patients with HER2 exon 20 insertion NSCLC.

Consensus for HER2 alterations testing in non-small-cell lung cancer

Human epidermal growth factor receptor 2 (HER2) is a transmembrane glycoprotein receptor with intracellular tyrosine kinase activity. Its alterations, including mutation, amplification and overexpression, could result in oncogenic potential and have been detected in many cancers such as non-small-cell lung cancer (NSCLC). Such alterations are, in general, considered markers of poor prognosis. Anti-HER2 antibody-drug conjugates, e.g. trastuzumab deruxtecan (T-DXd, DS-8201) and disitamab vedotin (RC48), were recently approved for HER2-positive breast and gastric cancers. Meanwhile, several HER2-targeted drugs, such as T-DXd, neratinib, afatinib, poziotinib and pyrotinib, have been evaluated in patients with advanced NSCLC, with several of them demonstrating clinical benefit. Therefore, identifying HER2 alterations is pivotal for NSCLC patients to benefit from these targeted therapies. Recent guidelines on HER2 testing were developed for breast and gastric cancer, however, and have not been fully established for NSCLC. The expert group here reached a consensus on HER2 alteration testing in NSCLC with the focus on clinicopathologic characteristics, therapies, detection methods and diagnostic criteria for HER2-altered NSCLC patients. We hope this consensus could improve the clinical management of NSCLC patients with HER2 alterations.

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Human epidermal growth factor receptor 2 (HER2) alterations lead to poor prognosis in non-small-cell lung cancer (NSCLC).

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Identifying HER2 alterations is pivotal to guide the anti-HER2-targeted therapies in NSCLC.

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The requirements for HER2 mutation, amplification or expression testing are distinct in NSCLC.

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This consensus fills the gap in the criteria for HER2 alteration testing in NSCLC.

Efficacy and safety of pyrotinib in advanced lung adenocarcinoma with HER2 mutations: a multicenter, single-arm, phase II trial

BACKGROUND

There is currently a lack of effective treatments for non-small cell lung cancer (NSCLC) patients harboring HER2 mutations. We examined the efficacy and safety of, and potential resistance mechanism to, pyrotinib, a pan-HER inhibitor, in advanced NSCLC carrying HER2 mutations.

METHODS

In this multicenter, single-arm, phase II trial, stage IIIB-IV NSCLC patients harboring HER2 mutations, as determined using next-generation sequencing, were enrolled and treated with pyrotinib at a dose of 400 mg/day. The primary endpoint was 6-month progression-free survival (PFS) rate, and secondary endpoints were objective response rate (ORR), PFS, overall survival (OS), disease control rate (DCR), and safety. The impact of different HER2 mutation types on sensitivity to pyrotinib and the potential of utilizing mutational profile derived from circulating tumor DNA (ctDNA) to predict disease progression were also explored.

RESULTS

Seventy-eight patients were enrolled for efficacy and safety analysis. The 6-month PFS rate was 49.5% (95% confidence interval [CI], 39.2-60.8). Pyrotinib produced an ORR of 19.2% (95% CI, 11.2-30.0), with median PFS of 5.6 months (95% CI, 2.8-8.4), and median OS of 10.5 months (95% CI, 8.7-12.3). The median duration of response was 9.9 months (95% CI, 6.2-13.6). All treatment-related adverse events (TRAEs) were grade 1-3 (all, 91.0%; grade 3, 20.5%), and the most common TRAE was diarrhea (all, 85.9%; grade 3, 16.7%). Patients with exon 20 and non-exon 20 HER2 mutations had ORRs of 17.7% and 25.0%, respectively. Brain metastases at baseline and prior exposure to afatinib were not associated with ORR, PFS, or OS. Loss of HER2 mutations and appearance of amplification in HER2 and EGFR were detected upon disease progression.

CONCLUSIONS

Pyrotinib exhibited promising efficacy and acceptable safety in NSCLC patients carrying exon 20 and non-exon 20 HER2 mutations and is worth further investigation.

TRIAL REGISTRATION

Chinese Clinical Trial Registry Identifier: ChiCTR1800020262.

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.

Morphologic, Immunohistochemical, and Genetic Differences Between High-grade and Low-grade Fetal Adenocarcinomas of the Lung

Fetal adenocarcinoma of the lung (FLAC) is a rare lung tumor classified into low-grade fetal adenocarcinoma of the lung (LG-FLAC) and high-grade fetal adenocarcinoma of the lung (HG-FLAC). It remains debatable whether HG-FLAC is a subset of FLAC or a distinct subtype of the conventional lung adenocarcinoma (CLA). In this study, samples of 4 LG-FLAC and 2 HG-FLAC cases were examined, and the clinicopathologic, immunohistochemical (IHC), and mutational differences between the 2 subtypes were analyzed using literature review. Morphologically, LG-FLACs had a pure pattern with complex glandular architecture composed of cells with subnuclear and supranuclear vacuoles, mimicking a developing fetal lung. In contrast, HG-FLACs contained both fetal lung-like (FLL) and CLA components. With regard to IHC markers, β-catenin exhibited a nuclear/cytoplasmic staining pattern in LG-FLACs but a membranous staining pattern in HG-FLACs. Furthermore, p53 was expressed diffusely and strongly in HG-FLACs, whereas in LG-FLACs, p53 staining was completely absent. Using next-generation sequencing targeting a 1021-gene panel, mutations of CTNNB1 and DICER1 were detected in all 4 LG-FLAC samples, and a novel mutation, MYCN P44L, was discovered in 2 LG-FLAC samples. DNA samples of the FLL and CLA components of HG-FLACs were separately extracted and sequenced. The FLL component harbored no CTNNB1, DICER1, or MYCN mutations; moreover, the FLL genetic profile largely overlapped with that of the CLA component. The morphologic, IHC, and genetic features of HG-FLAC indicate that it is a variant of CLA rather than a subset of FLAC. Thus, HG-FLAC should be treated differently from LG-FLAC.

Targeting HER2 Exon 20 Insertion-Mutant Lung Adenocarcinoma with a Novel Tyrosine Kinase Inhibitor Mobocertinib

No targeted treatments are currently approved for HER2 exon 20 insertion-mutant lung adenocarcinoma patients. Mobocertinib (TAK-788) is a potent irreversible tyrosine kinase inhibitor (TKI) designed to target human epidermal growth factor receptor 2 (HER2/ERBB2) exon 20 insertion mutations. However, the function of mobocertinib on HER2 exon 20 insertion-mutant lung cancer is still unclear. Here we conducted systematic characterization of preclinical models to understand the activity profile of mobocertinib against HER2 exon 20 insertions. In HER2 exon 20 insertion-mutant cell lines, the IC₅₀ of mobocertinib was higher than poziotinib and comparable with or slightly lower than afatinib, neratinib, and pyrotinib. Mobocertinib had the lowest HER2 exon 20 insertion IC₅₀/wild-type (WT) EGFR IC₅₀ ratio, indicating that mobocertinib displayed the best selectivity profile in these models. Also, mobocertinib showed strong inhibitory activity in HER2 exon 20^YVMA allograft and patient-derived xenograft models. In genetically engineered mouse models, HER2 exon 20^G776>VC lung tumors exhibited a sustained complete response to mobocertinib, whereas HER2 exon 20^YVMA tumors showed only partial and transient response. Combined treatment with a second antibody-drug conjugate (ADC) against HER2, ado-trastuzumab emtansine (T-DM1), synergized with mobocertinib in HER2 exon 20^YVMA tumors. In addition to the tumor cell autonomous effect, sustained tumor growth control derived from M1 macrophage infiltration and CD4⁺ T-cell activation. These findings support the ongoing clinical development of mobocertinib (NCT02716116) and provide a rationale for future clinical evaluation of T-DM1 combinational therapy in HER2 exon 20^YVMA insertion-mutant lung adenocarcinoma patients. SIGNIFICANCE: This study elucidates the potent inhibitory activity of mobocertinib against HER2 exon 20 insertion-mutant lung cancer and the synergic effect of combined mobocertinib and T-DM1, providing a strong rationale for clinical investigation.

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.

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.

Targeting HER2 genomic alterations in non-small cell lung cancer

Oncogenic mutations and amplifications in the erythroblastic oncogene B (ERBB2), or human epidermal growth factor receptor 2 (HER2), have emerged as distinct oncogenic drivers and drug targets in non-small cell lung cancer (NSCLC). Each genomic alteration occurs in 2-4% of NSCLC by next generation sequencing and is associated with constitutive HER2 activation. The most common HER2 mutations in NSCLC are exon 20 mutation A775_G776insYVMA mutation in the kinase domain and S310F mutation in the extracellular domain. Unlike in breast and gastric cancer, HER2 protein overexpression in NSCLC is not validated to be a biomarker predictive of clinical response to HER2-targeted agents. High HER2 protein overexpression by immunohistochemistry (3+) only occurs in 2-4% of NSCLC. Until now HER2-targeted agents (such as afatinib and ado-trastuzumab emtansine) only demonstrate modest clinical activity in patients with HER2-mutant NSCLC. Retrospective studies show concern for inferior clinical benefit of immune checkpoint inhibitors in HER2-mutated NSCLC. Therefore, platinum-based chemotherapy with or without an anti-angiogenesis inhibitor remains the first line standard treatment for this patient population. In May 2020 trastuzumab deruxtecan (T-DXd) received the U.S. Food and Drug Administration breakthrough therapy designation for HER2-mutant metastatic NSCLC, and was added as an option for HER2-mutant NSCLC to the NCCN guidelines V1.2021. A global phase III study of pyrotinib compared to docetaxel as a second line therapy for advanced NSCLC harboring HER2 exon 20 mutations was just opened for enrollment in September 2020. In this review, we highlight the current knowledge and perspectives on targeting-HER2 genomic alterations in NSCLC.

A narrative review of advances in treatment and survival prognosis of HER2-positive malignant lung cancers

Human epidermal growth factor receptor 2 (HER2), as a receptor tyrosine kinase of EGF receptor family, whose mutation is often associated with even if less frequency but poor prognosis and shorter survival in pulmonary malignant tumor. HER2 status include mutation, overexpression, amplification and also some rare genotypes, detected by next generation sequencing (NGS), immunohistochemistry (IHC), and also fluorescence in situ hybridization (FISH). Different genotypes represent different therapeutic targets and indicate different clinical prognosis concluded by previous studies. Unfortunately, no standard guidelines for first-line treatment are widely recognized, and current therapeutic schedules include chemotherapy, radiotherapy, targeted therapy, and immunotherapy. Especially for patients with advanced metastasis, chemotherapy is based as a systemic therapy using studies of breast cancer or EGFR-positive lung adenocarcinoma as a template. Studies already explored treatment including EGFR tyrosine kinase inhibitors (TKIs) such as gefitinib and afatinib, and also trastuzumab and its conjugation like HER2-targeted antibody-drug conjugate trastuzumab emtansine (T-DM1) and conjugate trastuzumab deruxtecan (T-DXd). Also, he researches explored combination therapy with chemotherapy and TKIs or monoclonal antibodies. This review describes commonly used therapies for HER2-positive/HER2-overexpression patients and general relationship between genotypes of HER2, drug selection and final prognosis in order to provide suggestions for future diagnosis and treatment.

Non-small-cell lung cancer with ERBB2 mutation in non-tyrosine kinase domain benefits from pyrotinib: A case report

Tyrosine kinase domain (TKD) mutation and particularly exon 20 insertion mutations of erb‐b2 receptor tyrosine kinase 2 (ERBB2/HER2) have been extensively reported in non‐small cell lung cancer (NSCLC). Nevertheless, the clinical significance of non‐TKD mutations remains unknown. To date, no clinical trials have revealed that tyrosine kinase inhibitors are effective in NSCLC patients with non‐TKD ERBB2 mutations. Here we report a patient with advanced lung adenocarcinoma harboring non‐TKD mutation of ERBB2, S335C, without other actionable alterations benefited from pyrotinib. After first‐line treatment of pyrotinib monotherapy, a pan‐HER inhibitor, the patient achieved a durable partial response with good tolerance. This case powerfully illustrates that pyrotinib might be a promising first‐line treatment strategy for NSCLC patients with non‐TKD mutation of ERBB2.

Exon 20 YVMA insertion is associated with high incidence of brain metastasis and inferior outcome of chemotherapy in advanced non-small cell lung cancer patients with HER2 kinase domain mutations

BACKGROUND

Chemotherapy remains the standard care for HER2 mutated advanced non-small cell lung cancer (NSCLC) even though several targeted drugs showed promising results in preliminary stages. This study aimed to investigate the association of mutation variants with clinical features and the efficacy of chemotherapy in patients with HER2 mutated advanced NSCLC.

METHODS

ARMS-PCR was used to identify HER2 mutation in patients without common oncogenic alterations. Patients with detailed information were further enrolled for analysis of clinical features and efficacy of first line chemotherapy. Survival data was analyzed by Kaplan-Meier method and compared by log-rank test. Brain metastasis incidence was analyzed and compared by Gray's test.

RESULTS

YVMA insertion accounted for the majority (68.4%, 67/98) of HER2 mutation, and associated with significantly higher incidence of baseline extrathoracic metastasis (P=0.009), notably brain metastasis (P=0.004). Among 82 patients those received first line chemotherapy, YVMA insertion remarkably associated with inferior treatment outcomes, namely, a significantly shorter median progression free survival (PFS) and lower objective response rate (ORR) both in total patients (PFS: 5.2 vs. 7.7 m, P=0.038; ORR: 30.9% vs. 51.9%, P=0.09) and pemetrexed subgroup (PFS: 5.2 vs. 6.5 m, P=0.022; ORR: 31.8% vs. 60.0%, P=0.054). Multivariate analysis further established YVMA insertion as prognostic factor of worse PFS both for total patients (HR =1.578, 95% CI, 0.956-2.606) and patients received pemetrexed-based chemotherapy (HR =1.789, 95% CI, 1.013-3.160). In addition, YVMA insertion associated with higher incidence of lifetime brain metastasis (P=0.002) compared by Gray's test, with estimated 12-month brain metastasis incidence as 40.2% compared with 3.6% in the non-YVMA group.

CONCLUSIONS

YVMA insertion is associated with a higher incidence of brain metastasis, and inferior outcomes to chemotherapy than non-YVMA variants in patients with advanced NSCLC and HER2 kinase domain mutations, which emphasized the unmet need of more potent anti-cancer therapies with high blood-brain barrier (BBB) penetration capacity for patients with YVMA insertion.

[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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Genomic characteristics of driver genes in Chinese patients with non-small cell lung cancer

BACKGROUND

The aim of this study was to determine the demographic profile of driver gene alterations, especially low-frequency gene alterations in Chinese patients with non-small cell lung cancer (NSCLC).

METHODS

A total of 7395 Chinese patients with NSCLC were enrolled in the study. Next-generation sequencing (NGS) was performed on formalin-fixed paraffin-embedded specimens collected via either surgical resection or biopsy.

RESULTS

The frequent genomic alterations found in the study were EGFR mutations (51.7%), KRAS mutations (13.1%), MET alterations (5.6%; 3.2% copy number gains and 0.5% exon 14 skipping mutation), HER2 alterations (7.0%; 2.0% copy number gains and 5.4% mutations), ALK alterations (7.2%; 3.9% rearrangements), RET rearrangements (1.4%), ROS1 rearrangements (0.9%), and NTRK rearrangements (0.6%). The EGFR mutation rate was found to be significantly higher in women than in men (69.1% vs. 38.5%, P < 0.001), while the KRAS mutation (17.5% vs. 7.3%, P < 0.001) and MET alteration rates (6.5% vs. 4.5%, P < 0.001) were significantly higher in men than in women. The EGFR mutation rate tended to decrease with age in the group aged >40 years, while the KRAS mutation rate tended to increase with age. The HER2 mutation (13.9% vs. 6.7%, P < 0.001) and ALK alteration rates (14.3% vs. 6.9%, P < 0.001) were significantly higher in the group aged <40 years than in groups aged 40 years or older.

CONCLUSIONS

The frequency of different driver genes was diverse in different age-gender groups, and the results of this study may assist clinicians in clinical decision-making and the development of public healthcare strategies in the future.

KEY POINTS

SIGNIFICANT FINDINGS OF THE STUDY: This study demonstrated that the frequency of different driver genes was diverse in different age-gender groups. What this study adds It may enable clinicians to make clinical decisions, and assist government, pharmaceutical researchers and insurance companies develop public healthcare strategies.

An ErbB2 splice variant lacking exon 16 drives lung carcinoma

Lung cancer causes more deaths annually than any other malignancy. A subset of non-small cell lung cancer (NSCLC) is driven by amplification and overexpression or activating mutation of the receptor tyrosine kinase (RTK) ERBB2 In some contexts, notably breast cancer, alternative splicing of ERBB2 causes skipping of exon 16, leading to the expression of an oncogenic ERBB2 isoform (ERBB2ΔEx16) that forms constitutively active homodimers. However, the broader implications of ERBB2 alternative splicing in human cancers have not been explored. Here, we have used genomic and transcriptomic analysis to identify elevated ERBB2ΔEx16 expression in a subset of NSCLC cases, as well as splicing site mutations facilitating exon 16 skipping and deletions of exon 16 in a subset of these lung tumors and in a number of other carcinomas. Supporting the potential of ERBB2ΔEx16 as a lung cancer driver, its expression transformed immortalized lung epithelial cells while a transgenic model featuring inducible ERBB2ΔEx16 specifically in the lung epithelium rapidly developed lung adenocarcinomas following transgene induction. Collectively, these observations indicate that ERBB2ΔEx16 is a lung cancer oncogene with potential clinical importance for a proportion of patients.

Clinical outcomes of patients with HER2-mutant advanced lung cancer: chemotherapies versus HER2-directed therapies

BACKGROUND

Lung cancer is now the leading cause of cancer mortality worldwide for both men and women. In non-small cell lung cancer (NSCLC), matching a specifically targeted drug to the identified driver mutation in each patient resulted in dramatically improved therapeutic efficacy, often in conjunction with decreased toxicity. Mutations in HER2 have been identified as an oncogenic driver gene for NSCLC. This retrospective study was conducted to better understand the clinical outcomes of advanced lung cancer patients harboring HER2 mutations treated with chemotherapies and HER2-targeted agents, as well as the optimal clinical choice.

METHODS

Patients who were diagnosed with advanced lung cancer (stage IIIB/IV) and had undergone molecular testing at Zhongshan Hospital, Fudan University, Shanghai, China from April 2016 to December 2018 were reviewed. For patients that had HER2 mutant advanced lung cancer, we analyzed their clinical and molecular features and clinical outcomes, including overall survival (OS), progression-free survival (PFS), disease control rate (DCR) and objective response rate (ORR).

RESULTS

We identified 44 patients harboring HER2 mutations. Their median age was 56 years, with the majority being women (n = 24), never smokers (n = 32), and having the adenocarcinoma genotype (n = 42). Amongst the HER2 mutations present, a 12 base pair in-frame insertion in exon 20 with p.771insAYVM was the most common subtype in patients with known detail variants of HER2 mutation (9/27). The median OS from the date of advanced disease diagnosis was 9.9 months with 24 deaths, and a median follow-up of 12.7 months for survivors. For patients with a known HER2 exon 20 insertion mutation, OS tended to be superior (though not statistically) in the first-line HER2-TKI group to that in the group receiving chemotherapy (10.8 versus 9.8 months, p = 0.40). However, patients that received first-line chemotherapy had a median PFS of 5.9 months, numerically longer than that of the HER2-TKI group (4.6 months, p = 0.63). Patients who received HER2-targeted therapy as first-line therapy had an improved OS (10.8 versus 10.1 months, p = 0.30) and PFS (4.6 versus 2.8 months, p = 0.36) relative to those who received HER2-targeted therapy as subsequent-line therapy, although they did not meet the threshold for statistical significance. Furthermore, patients with AYVM mutation were associated with poor clinical outcomes.

CONCLUSION

Pemetrexed-based chemotherapy remains an important component of care for patients with HER2-mutant NSCLC. HER2-TKI given as an initial therapy may bring more clinical benefits than when given as a subsequent-line therapy. Refining the patient population based on patterns of HER2 variants may help improve the efficacy of anti-HER2 treatment in lung cancer. Developing highly effective and tolerable HER2-targeted agents is urgently needed for this population.