Afatinib as first-line treatment for advanced lung adenocarcinoma patients harboring HER2 mutation: A case report and review of the literature

Discovery of potent and selective HER2 inhibitors with efficacy against HER2 exon 20 insertion-driven tumors, which preserve wild-type EGFR signaling

Oncogenic alterations in human epidermal growth factor receptor 2 (HER2) occur in approximately 2% of patients with non-small cell lung cancer and predominantly affect the tyrosine kinase domain and cluster in exon 20 of the ERBB2 gene. Most clinical-grade tyrosine kinase inhibitors are limited by either insufficient selectivity against wild-type (WT) epidermal growth factor receptor (EGFR), which is a major cause of dose-limiting toxicity or by potency against HER2 exon 20 mutant variants. Here we report the discovery of covalent tyrosine kinase inhibitors that potently inhibit HER2 exon 20 mutants while sparing WT EGFR, which reduce tumor cell survival and proliferation in vitro and result in regressions in preclinical xenograft models of HER2 exon 20 mutant non-small cell lung cancer, concomitant with inhibition of downstream HER2 signaling. Our results suggest that HER2 exon 20 insertion-driven tumors can be effectively treated by a potent and highly selective HER2 inhibitor while sparing WT EGFR, paving the way for clinical translation.

New Axially Chiral Molecular Scaffolds with Antibacterial Activities against Xanthomonas oryzae pv. oryzae for Protection of Rice

A new class of axially chiral thiazine molecules were constructed and showed promising antibacterial activities against the plant pathogen Xanthomonas oryzae pv. oryzae (Xoo). The axial chiralities of these compounds (R- or S-atropisomer) showed clear impacts on the in vitro inhibitory activities against Xoo. An optimal molecule of this class with the (S)-axially chiral configuration was identified to exhibit inhibitory activity against Xoo with an EC₅₀ value of 4.18 μg/mL. This inhibition efficiency is superior to that of two commercial antibacterial agrochemicals, thiodiazole-copper and bismerthiazol, as the positive controls. This hit compound also performed better than the controls in our in vivo studies. Preliminary mechanistic studies via scanning electron microscopy images showed that our hit compound at a concentration of 10 μg/mL destroyed the bacterial integrity of Xoo. Label-free quantitative proteomics analysis indicated that a total of 366 differentially expressed proteins of the rice plants were significantly influenced in the presence of our hit molecule.

Treatment of Resectable Gallbladder Cancer

Gallbladder cancer (GBC) is the most common biliary tract cancer worldwide and its incidence has significant geographic variation. A unique combination of predisposing factors includes genetic predisposition, geographic distribution, female gender, chronic inflammation, and congenital developmental abnormalities. Today, incidental GBC is the most common presentation of resectable gallbladder cancer, and surgery (minimally invasive or open) remains the only curative treatment available. Encouragingly, there is an important emerging role for systemic treatment for patients who have R1 resection or present with stage III-IV. In this article, we describe the pathogenesis, surgical and systemic treatment, and prognosis.

Identification of Recurrent Insertions and Deletions in Exon 18 and 19 of Human Epidermal Growth Factor Receptor 2 as Potential Drivers in Non-Small-Cell Lung Cancer and Other Cancer Types

PURPOSE

Human epidermal growth factor receptor 2 (HER2) belongs to the same family as epidermal growth factor receptor (EGFR) and is known as an important cancer driver gene. Insertions and deletions (indels) are frequent driver mutations in both EGFR and HER2. The most common HER2 indels are the exon 20 insertions within the kinase domain, while others are rarely reported. Our study aimed to investigate other indels of HER2 that may act as driver mutations in Chinese patients with different cancer types.

METHODS

In this retrospective study, patient samples were subjected to targeted sequencing covering HER2 and other cancer-related genes. Mutation profiles of patients harboring HER2 exon 18/19 indels were described. Identified HER2 exon 18/19 indels in our study were compared with external data from COSMIC. In silico and in vitro analyses were performed on selected indels of HER2 exon 18 and 19, respectively.

RESULTS

A total of 25 indels in HER2 exon 18/19, 17 of which being recurrent, were identified in 20 of 53,591 patients with lung cancer (0.037%), two of 5,888 patients with colorectal cancer (0.034%), two of 3,774 patients with breast cancer (0.053%), and one of 14 patients with urothelial carcinoma of the renal pelvis (7.1%). Most patients harboring HER2 exon 18/19 indels were absent of known driver mutations. In lung cancer, mutation profiles were comparable between patients carrying HER2 exon 18/19 indels and the two established HER2 drivers (exon 20 insertions and S310 mutations). The in silico and in vitro analyses suggested an activated state conferred by HER2 exon 18/19 indels, which could be targeted by different tyrosine kinase inhibitors.

CONCLUSION

Our study revealed a class of rare but unique indels in HER2 exon 18/19, which may act as driver mutations in several cancer types.

HER2 exon 18/19 indels identified in a small subset of patients may act as a novel class of cancer drivers.

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.

Mining Drug-Target Associations in Cancer: Analysis of Gene Expression and Drug Activity Correlations

Cancer is a complex disease affecting millions of people worldwide, with over a hundred clinically approved drugs available. In order to improve therapy, treatment, and response, it is essential to draw better maps of the targets of cancer drugs and possible side interactors. This study presents a large-scale screening method to find associations of cancer drugs with human genes. The analysis is focused on the current collection of Food and Drug Administration (FDA)-approved drugs (which includes about one hundred chemicals). The approach integrates global gene-expression transcriptomic profiles with drug-activity profiles of a set of 60 human cell lines obtained for a collection of chemical compounds (small bioactive molecules). Using a standardized expression for each gene versus standardized activity for each drug, Pearson and Spearman correlations were calculated for all possible pairwise gene-drug combinations. These correlations were used to build a global bipartite network that includes 1007 gene-drug significant associations. The data are integrated into an open web-tool called GEDA (Gene Expression and Drug Activity) which includes a relational view of cancer drugs and genes, disclosing the putative indirect interactions found for FDA-approved drugs as well as the known targets of these drugs. The results also provide insight into the complex action of pharmaceuticals, presenting an alternative view to address predicted pleiotropic effects of the drugs.

Mutational landscape and characteristics of ERBB2 in non-small cell lung cancer

BACKGROUND

Tyrosine kinase domain (TKD) mutation and particularly exon 20 insertion mutations of ERBB2 have been extensively reported in non-small cell lung cancer (NSCLC). Due to the increased accessibility of next-generation sequencing, more ERBB2 mutations within the non-TKD can be detected in clinical practice. Nevertheless, the clinical significance of non-TKD mutations remains unknown. Hence, this study was designed to comprehensively outline the landscape and characteristics of ERBB2 mutations in NSCLC.

METHODS

A total of 1934 patients with NSCLC from cBioPortal were included in the study. An ERBB2 mutation cohort was identified, while subsequent analyses revealed clinical and genomic characteristics.

RESULTS

The frequency of ERBB2 mutation was 4.5%, and it was determined to be more likely to occur in never-smokers. ERBB2 mutations occurring in the non-TKD accounted for 57.5% of ERBB2 mutations. In the non-TKD, missense mutation was the most recurrent mutation type, and S310F was the most recurrent mutation variant. ERBB2 mutations within non-TKD also had a strong oncogenic ability where up to 37.5% of ERBB2 oncogenic mutations were within non-TKD. The co-mutation of EGFR or KRAS was higher in the non-TKD mutation compared to the TKD mutation. Shorter overall survival was observed in ERBB2-mutant patients compared with ERBB2 wild-type patients. There was no significant difference in overall survival between patients with non-TKD mutations and TKD mutations.

CONCLUSIONS

The present study showed that a considerable portion of non-TKD mutations were oncogenic. ERBB2 mutation was a poor prognostic factor. The non-TKD mutation might also be used as a therapeutic target in ERBB2-directed target therapy.

KEY POINTS

• Significant findings of the study ERBB2 mutations were more abundant within a nontyrosine domain than those within the tyrosine domain. Up to 37.5% of ERBB2 oncogenic mutations were within the nontyrosine domain. ERBB2 mutation was a poor prognostic factor. • What this study adds The frequency of EGFR or KRAS co-mutations were significantly higher in ERBB2 mutations within the nontyrosine kinase domain compared to ERBB2 mutations within the tyrosine kinase domain. Nontyrosine domain mutations confer equal overall survival to tyrosine domain mutations.

Response to Afatinib in a Patient with Non-Small Cell Lung Cancer Harboring HER2 R896G Mutation: A Case Report

Purpose

HER2 mutations are identified in approximately 2% of non-small-cell lung cancer (NSCLC) cases; however, until now, there are no approved standard targeted therapy for NSCLC patients harboring HER2 mutations.

Case presentation

We present a 63-year-old male with a long smoking history, who was diagnosed with stage IV squamous cell lung cancer. After the failures of two lines of treatment with carboplatin plus gemcitabine and nidaplatin plus docetaxel, in turn, the patient received a next-generation sequencing of circulating tumor DNA to seek for potential treatment opportunities. A HER2 R896G mutation was identified with an allelic fraction of 50.77%. The patient received afatinib 40 mg a day and reached a partial response after two months of treatment. The progression-free survival was more than 14 months and the treatment of afatinib was ongoing. During the treatment, treatment-related paronychia and stomatitis occurred and relieved without any management.

Conclusion

This is the first case report describing a NSCLC patient harboring a rare HER2 R896G mutation who responds to afatinib. This case suggests that afatinib might be efficacious in NSCLC patients harboring HER2 R896G mutations, and these results need to be further studied in prospective clinical trials.

Prevalence and role of HER2 mutations in cancer

HER2 activating mutations act as oncogenic drivers in various cancer types. In the clinic, they can be identified by next generation sequencing (NGS) in either tumor biopsies or circulating cell-free DNA (cfDNA). Preclinical data indicate that HER2 "hot spot" mutations are constitutively active, have transforming capacity in vitro and in vivo and show variable sensitivity to anti-HER2 based therapies. Recent clinical trials also revealed activity of HER2-targeted drugs against a variety of tumors harboring HER2 mutations. Here, we review the prevalence and type of HER2 mutations identified in different human cancers, their biochemical and biological characterization, and their sensitivity to anti HER2-based therapies in both preclinical and clinical settings.