Targeting HER2 aberrations as actionable drivers in lung cancers: phase II trial of the pan-HER tyrosine kinase inhibitor dacomitinib in patients with HER2-mutant or amplified tumors

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.

Treatment of Rare Mutations in Patients with Lung Cancer

Lung cancer is a worldwide prevalent malignancy. This disease has a low survival rate due to diagnosis at a late stage challenged by the involvement of metastatic sites. Non-small-cell lung cancer (NSCLC) is presented in 85% of cases. The last decade has experienced substantial advancements in scientific research, leading to a novel targeted therapeutic approach. The newly developed pharmaceutical agents are aimed towards specific mutations, detected in individual patients inflicted by lung cancer. These drugs have longer and improved response rates compared to traditional chemotherapy. Recent studies were able to identify rare mutations found in pulmonary tumors. Among the gene alterations detected were mesenchymal epithelial transition factor (MET), human epidermal growth factor 2 (HER2), B-type Raf kinase (BRAF), c-ROS proto-oncogene (ROS1), rearranged during transfection (RET) and neurotrophic tyrosine kinase (NTRK). Ongoing clinical trials are gaining insight onto possible first and second lines of medical treatment options intended to enable progression-free survival to lung cancer patients.

Efficacy and Resistance of Afatinib in Chinese Non-Small Cell Lung Cancer Patients With HER2 Alterations: A Multicenter Retrospective Study

Background

Non-small cell lung cancer (NSCLC) patients with HER2 mutations and amplification may benefit from HER2-targeted therapy, including afatinib. However, the data regarding the clinical activity of afatinib in Chinese patients with NSCLC harboring HER2 alterations are limited.

Patients and methods

We retrospectively included metastatic NSCLC patients harboring HER2 alterations who treated with afatinib. The clinical outcomes included overall response rate (ORR), progression-free survival (PFS) and overall survival (OS). The genomic profiling data after progression on afatinib were analyzed.

Results

We included 54 patients harboring HER2 mutations and 12 patients harboring HER2 amplification. The ORR was 24% (95% CI, 16–36%), the median PFS was 3.3 months (95% CI, 2.2–4.4), and the median OS was 13.9 months (95% CI, 11.4–16.5). Patients with HER2 exon 20 mutations had numerically worse ORR (17% vs 42%), shorter PFS (2.6 vs 5.8 months, HR, 2.5; 95% CI, 1.2–5.5; P = 0.015) and OS (12.9 vs 33.3 months, HR, 4.4; 95% CI, 1.3–14.8; P = 0.009) than patients with other mutations. For HER2-amplified patients, the ORR was 33% (95% CI, 14–61%), the median PFS was 3.3 months (95% CI, 2.6–4.0), and the median OS was 13.4 months (95% CI, 0–27.6). The most frequently mutated genes in afatinib-resistant patients were TP53 (44%) and EGFR (33%). Three afatinib-resistant patients harbored secondary HER2 alterations.

Conclusions

Our results suggest that afatinib has a promising anti-tumor activity in patients with NSCLC harboring HER2 alterations. To our knowledge, this is the largest retrospective study about the clinical activity of afatinib in NSCLC patients with HER2 alterations.

Morphological, immunohistochemical, and genetic analyses of bronchiolar adenoma and its putative variants

We collected 26 cases of bronchiolar adenoma (BA) and its variants, and performed a comprehensive characterization using a combination of morphological, immunohistochemical, and genetic assessments. Of these 26, 13 were classic bilayered cases, including 10 proximal and 3 distal-type BAs. Of note, we also identified 13 cases that lacked a continuous basal cell layer. In five cases, the adenomas were partially classic bilayered, leaving a single layer of columnar or cuboidal epithelial cells in some areas of the lesion (BA with monolayered cell lesions). In the other eight cases, the glandular or papillary structures were entirely composed of monolayered columnar or cuboidal epithelial cells, which were morphologically identical to the luminal epithelial cells of classic BA (monolayered BA-like lesions). Immunohistochemical analysis revealed thyroid transcription factor 1 expression by ciliated columnar epithelial cells, basal cells, and nonciliated columnar and cuboidal epithelial cells. Basal cells also expressed p40 and p63. Twenty-five cases underwent next-generation sequencing using a 422-cancer-gene panel (GeneseeqPrime). Oncogenic driver mutations were detected in 23 cases, including 13 (52%) with EGFR mutations, 4 (16%) with KRAS G12D/V mutations, 3 (12%) with BRAF V600E mutations, 2 (8%) with ERBB2 exon 20 insertions, and 1 (4%) with a RET fusion. EGFR exon 20 insertions were present in 100% of BAs with monolayered cell lesions, 37.5% of monolayered BA-like lesions, and 8% of classic BA (Fisher's exact test, p = 0.002, false discovery rate = 0.014). Collectively, our study revealed a gradual morphological transition between BA and its variants. The genetic composition of BAs with monolayered structures differed significantly from those of classic BAs or lung adenocarcinoma.

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

Objective

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

Materials and Methods

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

Results

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

Conclusions

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

Poziotinib for EGFR and HER2 exon 20 insertion mutation in advanced NSCLC: Results from the expanded access program

BACKGROUND

The treatment of metastatic non-small-cell lung cancer (mNSCLC) patients with EGFR/HER2 exon 20 insertion mutation (i-mut) remains an unmet clinical need. Poziotinib, a new generation tyrosine kinase inhibitor, is currently under investigation as a potential targeted therapy. This compassionate study of its use aims to describe the activity/toxicity of poziotinib in mNSCLC with EGFR/HER2-exon-20-i-mut.

PATIENTS AND METHODS

NSCLC patients who were treated either with EGFR or HER2 exon 20-i-mut within an expanded access program were included in this study. Poziotinib (16 mg or less) was administrated orally quaque die (QD). The primary end-point was the overall response rate (ORR) assessed by central review using RECIST v1.1, and secondary end-points were median progression free survival (PFS), disease control rate (DCR), median overall survival (OS) and toxicity.

RESULTS

The median age of all the 30 patients was 58 years (25-80 years), most of them were females (73%); ECOG 0-1 (83%), EGFR i-mut (73%) and pre-treated (83%). 73% started with poziotinib at a dose of 16 mg. At data cut-off, 22 of 33 patients (73%) experienced a progress in the disease and 12 of 30 (40%) died. Median PFS was 5.6 months (95% CI: 3.6-6.7 months) and the mOS 9.5 months (95% CI: 5.3 - not-reached months). The ORR was 30% (EGFR/HER2: 23/50%) and DCR 80%. G3 AEs were reported in 66% of the patients and were found with skin rash (50%), diarrhoea (17.6%), mucositis (7%) and paronychia (3%). G5, possibly associated with pneumonitis might also have occurred.

CONCLUSIONS

Poziotinib exhibited effects in mNSCLC patients with EGFR/HER2-exon 20-i-mut. The toxicity rate was high leading to frequent dose interruption and reduction, thereby reducing mPFS in patients with good ORR/DCR. ZENITH20 trial is now being used to evaluate the low dose and new scheduled dose (e.g. bis in die (BID)).

Evidence for frequent concurrent DCUN1D1, FGFR1, BCL9 gene copy number amplification in squamous cell lung cancer

Non-small cell lung cancer (NSCLC) targeted therapies are mostly based on activating mutations and rearrangements which are rare events in Lung Squamous Cell Carcinomas (LUSC). Recently advances in immunotherapy have improved the therapeutic repository for LUSC, but there is still an urgent need for novel targets and biomarkers. We examined 73 cases of LUSC for relative copy number amplification of DCUN1D1, BCL9, FGFR1 and ERBB2 genes and searched for correlations with molecular alterations and clinicopathological characteristics. In our cohort BCL9 gene was amplified in 57.5 % of the cases, followed by DCUN1D1 in 37 %, FGFR1 in 19 % whereas none of the cases were amplified in ERBB2 gene. The majority of the samples exhibited amplification in at least one gene while half of them displayed concurrent amplification of two/three genes. Interestingly, 93 % of the FGFR1 amplified cases were also found co amplified with DCUN1D1 and/or BCL9 genes. Linear correlations were found between BCL9 and DCUN1D1 as well as BCL9 and FGFR1 gene amplification. BCL9 and DCUN1D1 genes' amplification was correlated with poorly differentiated tumors (p = 0.035 and p = 0.056 respectively), implying their possible role in tumor aggressiveness. This is the first study, to the best of our knowledge that examines the correlation of DCUN1D1 and BCL9 genes relative copy number amplification with molecular alterations and clinicopathologic characteristics of squamous cell lung cancer tissue samples. Our findings show concurrent amplification of genes in different chromosomes, with possible involvement in tumor aggressiveness. These results support the complexity of LUSC tumorigenesis and imply the necessity of multiple biomarkers / targets for a more effective therapeutic result in LUSC.

Uncommon targets in non-small cell lung cancer: Everyone wants a slice of cake

Target therapies completely changed the clinical approach in EGFR mutated and ALK rearranged non-small cell lung cancer, ensuring these patients exceptional outcomes with a better toxicity profile compared to conventional chemotherapy. In recent years, beyond EGFR and ALK alterations, new data are emerging about less common alterations, new drugs have been already approved and others agents have been recently investigated or are currently under investigation. In this review we will discuss some uncommon alterations in non-small cell lung cancer such as ROS1, BRAF, RET, HER2, NTRK, MET and other targets that are in an early evaluation phase. We will summarize the characteristics of patients harboring these alterations, the already approved or under investigation therapies and the related resistance mechanisms.

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.

Targeted Therapy in Advanced and Metastatic Non-Small Cell Lung Cancer. An Update on Treatment of the Most Important Actionable Oncogenic Driver Alterations

Due to groundbreaking developments and continuous progress, the treatment of advanced and metastatic non-small cell lung cancer (NSCLC) has become an exciting, but increasingly challenging task. This applies, in particular, to the subgroup of NSCLC with oncogenic driver alterations. While the treatment of epidermal growth factor receptor (EGFR)-mutated and anaplastic lymphoma kinase (ALK)-rearranged NSCLC with various tyrosine kinase inhibitors (TKIs) is well-established, new targets have been identified in the last few years and new TKIs introduced in clinical practice. Even for KRAS mutations, considered for a long time as an "un-targetable" alteration, promising new drugs are emerging. The detection and in-depth molecular analysis of resistance mechanisms has further fueled the development of new therapeutic strategies. The objective of this review is to give a comprehensive overview on the current landscape of targetable oncogenic alterations in NSCLC.

Studies on the Safety and Efficacy of Pyrotinib in the Treatment of HER2- Positive Advanced Solid Tumors Excluding Breast Cancer

Background

Human epidermal growth factor receptor 2 (H ER2) is a member of the ErbB family and is a key proto-oncogene in solid tumors. This pilot study investigated the safety and efficacy of pyrotinib in HER2-positive non-breast advanced solid tumors.

Patients and Methods

Twenty-five patients with HER2-positive advanced solid tumors excluding breast cancer were enrolled to receive pyrotinib-based therapy. The primary end point was progression-free survival (PFS).

Results

The median PFS and overall survival (OS) were 3.5 months (95% CI: 2.2-5.0 months) and 9.6 months (95% CI: 4.4-9.9 months), respectively. Ten patients with lung cancer and 9 patients with gastric cancer had a median PFS of 2.5 months (95% CI: 0.97-6.53 months) and 2.9 months (95% CI: 1.50-7.17 months), respectively. The median OS was 9.9 months (95% CI: 4.4-9.9 months) in patients with lung cancer and 5.9 months (95% CI: 4.0-9.6 months) in patients with gastric cancer. No statistical significance of a median OS was observed, nonetheless, patients receiving > 3 lines had a numerically lower median OS than those receiving ≤ 3 lines of treatment (9.9 vs 5.1 months, P = 0.706). All 23 patients were available for efficacy evaluation. The objective response rate (ORR) was 52.17% and disease control rate (DCR) was 91.3%. The ORR for lung cancer was 44.4% and for gastric cancer was 50%. In addition, the DCR for lung cancer was 77.8% and for stomach cancer was 100%. Moreover, patients receiving ≤3 lines of treatment had a numerically higher DCR than those receiving >3 lines of treatment (94.1% vs 83.3%, P = 0.462). The most common treatment-related adverse events (TRAEs) were diarrhea (92%), but only 5 (20%) patients reported grade 3 diarrhea which could be well controlled.

Conclusion

Pyrotinib-based therapy demonstrates promising efficacy for HER2-positive advanced solid tumors excluding breast cancer and toxicities could be well controlled. The study is a pilot study motivating larger studies to elucidate the safety and efficacy of pyrotinib in non-breast solid tumors.

Tarloxotinib Is a Hypoxia-Activated Pan-HER Kinase Inhibitor Active Against a Broad Range of HER-Family Oncogenes

PURPOSE

Approved therapies for EGFR exon 20, ERBB2 mutations, and NRG1 fusions are currently lacking for non-small cell lung cancer and other cancers. Tarloxotinib is a prodrug that harnesses tumor hypoxia to generate high levels of a potent, covalent pan-HER tyrosine kinase inhibitor, tarloxotinib-effector (tarloxotinib-E), within the tumor microenvironment. This tumor-selective delivery mechanism was designed to minimize the dose-limiting toxicities that are characteristic of systemic inhibition of wild-type EGFR.

EXPERIMENTAL DESIGN

Novel and existing patient-derived cell lines and xenografts harboring EGFR exon 20 insertion mutations, ERBB2 mutations and amplification, and NRG1 fusions were tested in vitro and in vivo with tarloxotinib to determine its impact on cancer cell proliferation, apoptosis, and cell signaling.

RESULTS

Tarloxotinib-E inhibited cell signaling and proliferation in patient-derived cancer models in vitro by directly inhibiting phosphorylation and activation of EGFR, HER2, and HER2/HER3 heterodimers. In vivo, tarloxotinib induced tumor regression or growth inhibition in multiple murine xenograft models. Pharmacokinetic analysis confirmed markedly higher levels of tarloxotinib-E in tumor tissue than plasma or skin. Finally, a patient with lung adenocarcinoma harboring an ERBB2 exon 20 p.A775_G776insYVMA mutation demonstrated a dramatic clinical response to tarloxotinib.

CONCLUSIONS

Experimental data with tarloxotinib validate the novel mechanism of action of a hypoxia-activated prodrug in cancer models by concentrating active drug in the tumor versus normal tissue, and this activity can translate into clinical activity in patients.

[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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Targeting Infrequent Driver Alterations in Non-Small Cell Lung Cancer

The discovery of oncogenic driver mutations led to the development of targeted therapies with non-small cell lung cancer (NSCLC) being a paradigm for precision medicine in this setting. Nowadays, the number of clinical trials focusing on targeted therapies for uncommon drivers is growing exponentially, emphasizing the medical need for these patients. Unfortunately, similar to what is observed with most targeted therapies directed against a driver oncogene, the clinical response is almost always temporary and acquired resistance to these drugs invariably emerges. Here, we review the biology of infrequent genomic actionable alterations in NSCLC as well as the current and emerging therapeutic options for these patients. Mechanisms leading to acquired drug resistance and future challenges in the field are also discussed.

Dacomitinib induces objective responses in metastatic brain lesions of patients with EGFR-mutant non-small-cell lung cancer: A brief report

OBJECTIVE

Dacomitinib is a potent, irreversible and pan-HER tyrosine kinase inhibitor (TKI) of epidermal growth factor receptor (EGFR) mutant non-small cell lung cancer (NSCLC). Currently, evidence of its activity on brain metastasis is lacking.

MATERIALS AND METHODS

NSCLC patients diagnosed at Hunan Cancer Hospital between July, 2019 and July, 2020 with enhanced MRI-detected brain metastasis prior to treatment and laboratory-confirmed EGFR mutations were reviewed. In total, 14 EGFR-mutant NSCLC patients with brain metastasis were treated with first-line dacomitinib. The first radiographic review of chest CT and brain MRI was after one month and thereafter every 2 months. The objective response rate (ORR) and the depth of the brain metastasis response were determined via RECIST 1.1 and RANO-LM criteria.

RESULTS

In total, 14 of 59 EGFR-mutant advanced NSCLC patients who received first-line dacomitinib therapy had brain metastasis before treatment. Among these patients, 5 were given a dacomitinib starting dose of 45 mg once daily, while 9 received 30 mg daily until disease progression or unbearable toxicity. Eight patients harbored EGFR 19del, 5 had EGFR L858R, and one patient had EGFR G719A and I706 T co-mutations. The median duration of follow-up was 4.5 months. All patients received at least one review. The ORR was 92.9 % (13/14) and the disease control rate (DCR) was 100 %. A measurable response of the intracranial metastases was observed in 12 of 14 patients (85.7 %), including 12 of 13 (92.3 %) with brain parenchymal metastasis, but the one patient with meningeal metastasis did not respond well. All patients (100 %) had grade 1-2 adverse effects, but none discontinued treatment or required a dosage adjustment.

CONCLUSIONS

This case series study of 14 patients has shown that dacomitinib has potent efficacy for central nervous system (CNS) metastasis in EGFR-positive NSCLC. More data are required to confirm its advantages and optimize its clinical application.

Beneficial effect of erlotinib and trastuzumab emtansine combination in lung tumors harboring EGFR mutations

Epidermal growth factor receptor-tyrosine kinase inhibitors (EGFR-TKIs) is the standard therapy for non-small cell lung cancer (NSCLC) harboring EGFR mutations, but the resistance is inevitable. The drug-tolerant persister cancer cells are thought to be involved in the resistance. We recently reported that HER2 expression had a negative impact on time-to-treatment-failure in patients with EGFR mutant NSCLC. In this study, we hypothesized that HER2 might be a potential target for alternative combination therapy in NSCLC harboring EGFR mutations. In vitro study showed that the level of HER2 expression had no correlation with the sensitivity to EGFR-TKI, erlotinib but showed some correlation with HER2-inhibitor, ado-trastuzumab emtansine (T-DM1) in multiple EGFR-mutant lung cancer cell lines. In addition, HER2 expression was increased in persister cancer cells in 11-18 cell line harboring EGFR L858R or HCC827 cell line harboring EGFR exon 19 deletion after the exposure to erlotinib in vitro and in vivo. The combination of erlotinib and T-DM1 showed a superior inhibitory effect on cell proliferation compared with those of the erlotinib or T-DM1 alone in either 11-18 or HCC827 cells in vitro. The combination therapy also induced a significantly greater inhibitory effect on tumor growth in xenograft model in mice transplanted with either 11-18 or HCC827 cells compared with erlotinib alone or T-DM1 alone. No body weight loss was observed in these mice. These results suggested that the combination therapy with EGFR-TKI and T-DM1 might be a potentially promising strategy for treating lung cancer harboring EGFR mutations.

Advances in Treatment of Locally Advanced or Metastatic Non-Small Cell Lung Cancer: Targeted Therapy

The treatment of metastatic non-small cell lung cancer (NSCLC) is constantly evolving. Although the advent of immunotherapy has played an important role in the treatment of patients with NSCLC, the identification of driver mutations and the subsequent specific treatment of these targets often lead to durable responses while maintaining quality of life. This review delves into targeted therapies available for epidermal growth factor receptor, anaplastic lymphoma kinase, ROS1, neurotrophic tropomyosin receptor kinase, and BRAF- mutated NSCLC patients, as well as other mutations with promising novel drugs under clinical investigation.

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

PURPOSE

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

METHODS

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

RESULTS

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

CONCLUSION

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

Efficacy of Pyrotinib in a Heavily Pretreated Patient with Lung Adenocarcinoma Harboring HER2 Amplification and Exon 20 Insertions: A Case Report

The clinical benefits of HER2 inhibitors in patients with non-small cell lung cancer (NSCLC) have been limited. There is a paucity of effective therapies in NSCLC after developing resistance to initial anti-HER2 therapy. Herein, we presented the clinical benefit of pyrotinib in a 53-year-old patient with advanced lung adenocarcinoma whose circulating tumor DNA (ctDNA) analysis of pleural effusion revealed the coexistence of HER2 exon 20 p.Y772_A775dup (mutation ratio: 38.86%) and HER2 amplification (copy number: 4.5) following failures of multiple therapies including afatinib and ado-trastuzumab emtansine (T-DM1). Notably, pyrotinib treatment induced rapid and marked improvement of clinical symptoms, and partial response was observed after 8 weeks. CtDNA monitoring during the treatment showed that the mutation ratio of HER2 decreased to 7.99%, and the amplification disappeared. The patient achieved a progression-free survival of 7.5 months after treatment with pyrotinib. Thus, pyrotinib may be a new treatment strategy for the subgroup of lung adenocarcinoma patients, with coexistence of HER2 exon 20 p.Y772_A775dup and HER2 amplification even after failures of multiple anti-HER2 therapies. It also indicated the value of capture-based next-generation sequencing to monitor and guide therapy.

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.

Retrospective analysis of real-world data to determine clinical outcomes of patients with advanced non-small cell lung cancer following cell-free circulating tumor DNA genomic profiling

OBJECTIVES

Liquid biopsy and comprehensive genomic profiling (CGP) of circulating tumor DNA (ctDNA) are increasingly used for detection of targetable genomic alterations (GA) in non-small cell lung cancer (NSCLC). To examine the clinical outcomes for patients following CGP using liquid biopsy versus tissue biopsy, receipt of matched targeted therapy post-CGP and associated outcomes were evaluated in the real-world setting.

METHODS

6491 patients with NSCLC and liquid biopsy (N = 937 tests) and/or tissue (N = 5582 tests) CGP were included in a de-identified commercial clinico-genomic database. Targetable GAs included National Comprehensive Cancer Network NSCLC guideline biomarkers. Clinical characteristics, real-world progression, and real-world response (rwR) were obtained via technology-enabled abstraction of clinician notes and radiology/pathology reports.

RESULTS

At the time of liquid biopsy CGP, 53% (496/937) of patients were documented to have received ≥1 line of prior therapy (tissue CGP: 13%, 735/5582). 90% (832/928) of liquid biopsy cases had evidence of ctDNA. A targetable GA was detected in 20% (188/937) of liquid biopsy and 22% (1215/5582) of tissue CGP cases. Use of matched targeted therapy overall was similar post-liquid biopsy or post-tissue CGP but varied considerably across emerging (25%, 79/317) versus standard of care (SOC) (74%, 475/640) GA. Real-world-progression free survival for patients receiving SOC first line matched targeted therapy administered following liquid biopsy (n = 33) and tissue (n = 229) CGP were similar (13.8 vs 10.6 months; aHR = 0.68 [0.36-1.26]). Among patients evaluated for rwR, overall response rate (partial/complete response) to matched targeted therapy post-liquid biopsy CGP was 75% (39/52) versus 66% post-tissue CGP (254/385, P = 0.51).

CONCLUSION

Retrospective analysis of real-world clinico-genomic data demonstrated that clinical outcomes on matched targeted therapy were similar following liquid biopsy and tissue CGP in NSCLC, which suggests routine clinical use of liquid biopsy CGP can reliably guide therapy selection.

Next-Generation Sequencing at High Sequencing Depth as a Tool to Study the Evolution of Metastasis Driven by Genetic Change Events of Lung Squamous Cell Carcinoma

Background: The aim of this study is to report tumoral genetic mutations observed at high sequencing depth in a lung squamous cell carcinoma (SqCC) sample. We describe the findings and differences in genetic mutations that were studied by deep next-generation sequencing methods on the primary tumor and liver metastasis samples. In this report, we also discuss how these differences may be involved in determining the tumor progression leading to the metastasis stage.

Methods: We followed one lung SqCC patient who underwent FDG-PET scan imaging, before and after three months of treatment. We sequenced 26 well-known cancer-related genes, at an average of ~6,000 × sequencing coverage, in two spatially distinct regions, one from a primary lung tumor metastasis and the other from a distal liver metastasis, which was present before the treatment.

Results: A total of 3,922,196 read pairs were obtained across all two samples' sequenced locations. Merged mapped reads showed several variants, from which we selected 36 with high confidence call. While we found 83% of genetic concordance between the distal metastasis and primary tumor, six variants presented substantial discordance. In the liver metastasis sample, we observed three de novo genetic changes, two on the FGFR3 gene and one on the CDKN2A gene, and the frequency of one variant found on the FGFR2 gene has been increased. Two genetic variants in the HRAS gene, which were present initially in the primary tumor, have been completely lost in the liver tumor. The discordant variants have coding consequences as follows: FGFR3 (c.746C>G, p. Ser249Cys), CDKN2A (c.47_50delTGGC, p. Leu16Profs^*9), and HRAS (c.182A>C, p. Gln61Pro). The pathogenicity prediction scores for the acquired variants, assessed using several databases, reported these variants as pathogenic, with a gain of function for FGFR3 and a loss of function for CDKN2A. The patient follow-up using imaging with 18F-FDG PET/CT before and after four cycles of treatment shows discordant tumor progression in metastatic liver compared to primary lung tumor.

Conclusions: Our results report the occurrence of several genetic changes between primary tumor and distant liver metastasis in lung SqCC, among which non-silent mutations may be associated with tumor evolution during metastasis.

The efficacy of ado-trastuzumab emtansine in patients with ERBB2-aberrant non-small cell lung cancer: a systematic review

BACKGROUND

ERBB2 aberrations are oncogenic alterations in lung cancer. However, the reported therapeutic efficacy of ado-trastuzumab emtansine (T-DM1) varied. We therefore evaluated the efficacy and safety of T-DM1 in treating different types of ERBB2 aberrations.

METHODS

We conducted a systematic search for original articles and meeting abstracts about ERBB2-aberrant lung cancer treating with T-DM1 in PubMed and EMBASE databases from inception to June, 2020. Statistical analysis was carried out in R software.

RESULTS

A total of 120 patients with various ERBB2 aberrations were identified in five studies. ERBB2 upregulation (gene amplification and/or protein overexpression) was more common in smokers with adenocarcinoma, whereas mutations were more common in female non-smokers with adenocarcinoma. The overall objective response rate (ORR) for ERBB2 aberrations was 29% [95% confidence interval (CI): 15-56%]. Subgroup analysis showed an ORR of 41% (95% CI: 11-70%) for ERBB2 gene mutation, 66% (95% CI: 11-100%) for ERBB2 gene amplification, and 3% (95% CI: 0-9%) for ERBB2 protein overexpression. Notably, the ORR was 44% (95% CI: 25-63%) upon concomitant ERBB2 upregulation and mutation. Furthermore, the ORR was 26% (95% CI: 0-54%) for protein overexpression plus gene mutation but up to 80% (95% CI: 50-100%) for triple aberrations: gene amplification plus protein overexpression and gene mutation.

CONCLUSIONS

Collectively, T-DM1 might be a critical agent targeting ERBB2 mutated or/and amplified lung cancers.

HER2 Exon 20 Insertion Mutations in Lung Adenocarcinoma: Case Series and Response to Pyrotinib

HER2 mutations have emerged as oncogenic driver gene mutations in non-small cell lung cancer (NSCLC), which have not been described in detail like other driver gene mutations. Here, 295 patients with advanced lung adenocarcinoma were retrospectively screened for HER2 mutations using next-generation sequencing (NGS), and the positive cases were validated by Sanger sequencing. We identified five cases with HER2 exon 20 insertions, representing 1.7% of 295 lung adenocarcinomas. Among them, four different subtypes of HER2 exon 20 insertions were identified, including a rare subtype G778_S779insCPG never reported before with a partial response (PR) to pyrotinib and progression-free survival (PFS) of 12.8 months. Our findings reveal that HER2 exon 20 insertion mutations were detected in a small subset of lung adenocarcinomas. Given the different drug sensitivities, determining the mutation subtype by next-generation sequencing at the time of diagnosis might make sense.

Afatinib in patients with advanced non-small cell lung cancer harboring HER2 mutations, previously treated with chemotherapy: A phase II trial

BACKGROUND

Despite 1-4 % of NSCLC tumors harboring mutations in the HER2 gene, there are no approved HER2-pathway-targeted treatments available. We report an open-label, single-arm, multicenter phase II study investigating the efficacy and safety of afatinib in Asian patients with HER2-mutation positive (HER2m+) NSCLC.

METHODS

Eligible patients for Part A had confirmed stage IIIb/IV HER2m + NSCLC, had failed one or two prior lines of chemotherapy, and were EGFR/HER2-inhibitor naïve. Patients received oral afatinib 40 mg/day in continuous 28-day cycles, until disease progression or intolerable adverse events (AEs). Patients qualified for Part B if they had > 12 weeks' clinical benefit and Eastern Cooperative Oncology Group performance status ≤ 2. In Part B, patients were to receive afatinib at the last received dose, plus paclitaxel 80 mg/m² weekly, until disease progression or intolerable AEs. The primary endpoint in Part A was objective response (OR); secondary endpoints included disease control (DC), progression-free survival (PFS), and overall survival (OS). Further exploratory endpoints were OR, DC, and PFS in Part B.

RESULTS

Eighteen patients received afatinib in Part A. No patient achieved an OR; 11 patients (61.1 %) achieved stable disease, and six patients (33.3 %) had progressive disease. DC rate was therefore 61.1 % (95 % confidence interval [CI]: 35.7, 82.7). A decrease in tumor size from baseline of > 0 to < 30 % was observed in eight patients. At the time of analysis, 16 patients (88.9 %) had progressed or died. Median PFS was 2.76 months (95 % CI: 1.87, 4.60) and median OS was 10.02 months (95 % CI: 8.47, 10.08). All patients experienced ≥ 1 AE, most commonly diarrhea (66.7 %) and rash (33.3 %). No patients met the inclusion criteria for Part B, and recruitment was slow; therefore, the study was terminated.

CONCLUSIONS

This study found no clinical benefit of afatinib for EGFR TKI-naïve patients with HER2m + NSCLC.

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

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

Molecular therapeutic targets in non-small cell lung cancer

INTRODUCTION

Several targetable genetic alterations have been identified in non-small cell lung cancers (NSCLC) and drugs targeting these alterations have been approved for the management of advanced NSCLC patients. Driver mutations with emerging clinical trial data include EGFR exon 20 insertion mutations, MET amplification, KRAS G12 C point mutations, RET rearrangements, HER2 amplification and mutations, and FGFR amplification and translocations.

AREAS COVERED

We reviewed English-language articles indexed in Medline and PubMed up to the 1^st of June 2020. In addition, the proceedings of major conferences were reviewed for relevant abstracts. We report data published regarding targeted therapies which are currently approved and for those which are emerging in advanced or metastatic NSCLC.

EXPERT REVIEW

While these drugs have been shown to be efficacious and tolerable, resistance almost always develops. Though next-generation tyrosine kinase inhibitors (TKIs) have been developed, the appropriate sequencing of these drugs is not clear. Evaluating combination therapies to prevent or delay the onset of resistance and understanding mechanisms of resistance are critical areas of emerging research.

Pyrotinib in HER2-Mutant Advanced Lung Adenocarcinoma After Platinum-Based Chemotherapy: A Multicenter, Open-Label, Single-Arm, Phase II Study

PURPOSE

Targeted therapies against non-small-cell lung cancer (NSCLC) harboring HER2 mutations remain an unmet need. In this study, we assessed the efficacy and safety of pyrotinib in patients with HER2-mutant advanced NSCLC in a prospective, multicenter, open-label, single-arm, phase II study.

PATIENTS AND METHODS

Patients with stage IIIB or IV HER2-mutant lung adenocarcinoma who were previously treated with platinum-based chemotherapy were enrolled to receive pyrotinib at a dose of 400 mg/d for 21-day cycles. The primary end point was objective response rate per independent review committee (IRC).

RESULTS

Between October 20, 2016, and December 10, 2018, 60 patients received pyrotinib monotherapy. At baseline, 58 (96.7%) were stage IV, and 25 (41.7%) received at least 2 lines of prior chemotherapy. As of data cutoff on June 20, 2019, IRC-assessed objective response rate was 30.0% (95% CI, 18.8% to 43.2%). All subgroups of patients with different HER2 mutation types showed a favorable objective response rate. The objective response rates were similar between patients with and without brain metastases (25.0% v 31.3%). The median duration of response was 6.9 months (95% CI, 4.9 to 11.1 months). The median progression-free survival was 6.9 months (95% CI, 5.5 to 8.3 months) per IRC. The median overall survival was 14.4 months (95% CI, 12.3 to 21.3 months). Treatment-related adverse events of grade 3 or 4 occurred in 28.3% of patients, with the most common being diarrhea (20.0%; all grade 3). No treatment-related deaths were reported.

CONCLUSION

Pyrotinib showed promising antitumor activity and an acceptable safety profile in chemotherapy-treated patients with HER2-mutant NSCLC.

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.

Successful treatment of pyrotinib for bone marrow metastasis induced pancytopenia in a patient with non-small-cell lung cancer and ERBB2 mutation

ERBB2 mutations are found in about 2% of patients with non‐small cell lung cancer (NSCLC). A recent study reported that pyrotinib (an irreversible pan ErbB inhibitor) had superior antitumor effect compared to other tyrosine kinase inhibitor therapies in patients with ERBB2 mutations. Bone marrow metastasis is rare in lung adenocarcinoma, and has been reported to be associated with poor prognosis. Here, we report the case of a 62‐year‐old female diagnosed with lung adenocarcinoma and bone marrow metastasis. ERBB2 exon 20 insertion mutation was confirmed by next‐generation sequencing (NGS) of lung tissue as well as bone marrow. The patient achieved stable disease and recovery of pancytopenia after two months of pyrotinib therapy. This is the first report of homogenous mutations of ERBB2 detected in bone marrow, as well as a good response of bone marrow to pyrotinib therapy.

Key points

This is the first report of a homogenous mutation of ERBB2 detected in the bone marrow of an NSCLC patient with bone marrow metastasis.

Our patient with NSCLC ERBB2 mutation and bone marrow metastasis responded well to pyrotinib therapy.

Co-Occurring Alterations of ERBB2 Exon 20 Insertion in Non-Small Cell Lung Cancer (NSCLC) and the Potential Indicator of Response to Afatinib

Background: Human epidermal growth factor receptor 2 (ERBB2, HER-2) exon 20 insertion (ERBB2ex20ins) remains a refractory oncogenic driver in lung cancer. So far there is limited data showing the co-occurring mutation background of ERBB2ex20ins in Chinese lung cancer and its relationship with response to afatinib. Patients and Methods: A total of 112 Chinese patients with ERBB2ex20ins identified by next-generation sequencing from 17 hospitals were enrolled. The clinical outcomes of 18 patients receiving afatinib treatment were collected. Results: Among the 112 patients, insertion-site subtypes comprised of A775ins (71%; 79/112), G776indel (17%; 19/112), and P780ins (12%; 14/112). There were 66.1% (74/112) of patients carrying TP53 co-mutation and FOXA1 was the most prevalent co-amplified gene (5.5%, 3/55). The co-occurring genomic feature was similar among three insertional-site subtypes and had an overall strong concordance with the western population from the MSKCC cohort (R ² = 0.74, P < 0.01). For the prognosis, patients with co-occurring mutation in cell-cycle pathway especially TP53 showed shorter OS than patients without [median OS: 14.5 m (95% CI:12.7-16.3 m) vs. 30.3 m (95% CI: not reached), p = 0.04], while the OS was comparable among three subtypes. For the response to afatinib, ERBB2ex20ins as a subclonal variant was an independent factor relating to shorter PFS [median PFS: 1.2 m (95% CI: 0.8-1.6 m) vs. 4.3 m (95% CI: 3.3-5.3 m), p < 0.05]. Conclusion: Our data revealed co-occurring TP53 represent an unfavorable prognosis of patients with ERBB2ex20ins, emphasizing the more valuable role of the co-mutation patterns than insertion-site subtypes in predicting prognosis of this group of patients. Moreover, the clonality status of ERBB2ex20ins was identified as a potential indicator for response to afatinib.

Oncogene-Addicted Non-Small-Cell Lung Cancer: Treatment Opportunities and Future Perspectives

Before the introduction of tyrosine kinase inhibitors (TKIs) for a particular subgroup of patients, despite platinum-based combination chemotherapy, the majority of patients affected by non-small-cell lung cancer (NSCLC) did not live longer than one year. With deeper understanding of tumor molecular biology, treatment of NSCLC has progressively entered the era of treatment customization according to tumor molecular characteristics, as well as histology. All this information allowed the development of personalized molecular targeted therapies. A series of studies have shown that, in some cases, cancer cells can grow and survive as result of the presence of a single driver genomic abnormality. This phenomenon, called oncogene-addiction, more often occurs in adenocarcinoma histology, in non-smokers (except BRAF mutations, also frequent in smoking patients), young, and female patients. Several different driver mutations have been identified and many studies have clearly shown that upfront TKI monotherapy may improve the overall outcome of these patients. The greater efficacy of these drugs is also associated with a better tolerability and safety than chemotherapy, with fewer side effects and an extremely good compliance to treatment. The most frequent oncogene-addicted disease is represented by those tumors carrying a mutation of the epidermal growth factor receptor (EGFR). The development of first, second and third generation TKIs against EGFR mutations have dramatically changed the prognosis of these patients. Currently, osimertinib (which demonstrated to improve efficacy with a better tolerability in comparison with first-generation TKIs) is considered the best treatment option for patients affected by NSCLC harboring a common EGFR mutation. EML4-ALK-driven disease (which gene re-arrangement occurs in 3-7% of NSCLC), has demonstrated to be significantly targeted by specific TKIs, which have improved outcome in comparison with chemotherapy. To date, alectinib is considered the best treatment option for these patients, with other newer agents upcoming. Other additional driver abnormalities, such as ROS1, BRAF, MET, RET and NTRK, have been identified as a target mirroring peculiar vulnerability to specific agents. Oncogene-addicted disease typically has a low early resistance rate, but late acquired resistance always develops and therefore therapy needs to be changed when progression occurs. In this narrative review, the state of art of scientific literature about targeted therapy options in oncogene-addicted disease is summarized and critically discussed. We also aim to analyze future perspectives to maximize benefits for this subgroup of patients.

HER2-Mediated Internalization of Cytotoxic Agents in ERBB2 Amplified or Mutant Lung Cancers

Amplification of and oncogenic mutations in ERBB2, the gene encoding the HER2 receptor tyrosine kinase, promote receptor hyperactivation and tumor growth. Here we demonstrate that HER2 ubiquitination and internalization, rather than its overexpression, are key mechanisms underlying endocytosis and consequent efficacy of the anti-HER2 antibody-drug conjugates (ADC) ado-trastuzumab emtansine (T-DM1) and trastuzumab deruxtecan (T-DXd) in lung cancer cell lines and patient-derived xenograft models. These data translated into a 51% response rate in a clinical trial of T-DM1 in 49 patients with ERBB2-amplified or -mutant lung cancers. We show that cotreatment with irreversible pan-HER inhibitors enhances receptor ubiquitination and consequent ADC internalization and efficacy. We also demonstrate that ADC switching to T-DXd, which harbors a different cytotoxic payload, achieves durable responses in a patient with lung cancer and corresponding xenograft model developing resistance to T-DM1. Our findings may help guide future clinical trials and expand the field of ADC as cancer therapy. SIGNIFICANCE: T-DM1 is clinically effective in lung cancers with amplification of or mutations in ERBB2. This activity is enhanced by cotreatment with irreversible pan-HER inhibitors, or ADC switching to T-DXd. These results may help address unmet needs of patients with HER2-activated tumors and no approved targeted therapy.See related commentary by Rolfo and Russo, p. 643.This article is highlighted in the In This Issue feature, p. 627.

The efficacy of afatinib in patients with HER2 mutant non-small cell lung cancer: a meta-analysis

BACKGROUND

Erb-b2 receptor tyrosine kinase 2 (ErbB2/HER2) mutation has been found in approximately 2-4% of non-small cell lung cancer (NSCLC) patients and has been identified as one of carcinogenic mutations. Afatinib, a member of irreversible HER family inhibitor, has been investigated by a number of literatures, yet whose therapeutic efficiency remains uncertain in NSCLC with HER2 mutation. To elucidate the clinical efficacy and safety of afatinib in treating HER2 mutant NSCLC, we integrated and reanalyzed the data from current available studies.

METHODS

We conducted a systematic literature search for published articles regarding afatinib treating HER2-mutant lung cancer. Eight studies met the inclusion and exclusion criteria. The main outcomes were the objective response rate (ORR) and disease control rate (DCR).

RESULTS

Ninety-five patients with HER2 mutations were identified from eight studies. The pooled ORR was 21% (95% CI: 11-34%) and the pooled DCR was 66% (95% CI: 57-76%). The patients harboring A775-G776ins YVMA mutation, the most common subtype of HER2 exon 20 mutation, derived greater clinical benefit. Most adverse events were grade 1-2, except a case of fatal acute renal injury, possibly related to afatinib.

CONCLUSIONS

Afatinib monotherapy demonstrated frustrating anti-tumor activity with tolerable toxicity in HER2 mutant NSCLC. Based on current available data, we do not recommend the regular application of afatinib in NSCLC with HER2 mutations unless the response heterogeneity with specific genomic variant of HER2 mutation was further clarified.

New Targets in Lung Cancer (Excluding EGFR, ALK, ROS1)

PURPOSE OF REVIEW

Over the last two decades, the identification of targetable oncogene drivers has revolutionized the therapeutic landscape of non-small cell lung cancer (NSCLC). The extraordinary progresses made in molecular biology prompted the identification of several rare molecularly defined subgroups. In this review, we will focus on the novel and emerging actionable oncogenic drivers in NSCLC.

RECENT FINDINGS

Recently, novel oncogene drivers emerged as promising therapeutic targets besides the well-established EGFR mutations, and ALK/ROS1 rearrangements, considerably expanding the list of potential exploitable genetic aberrations. However, the therapeutic algorithm in these patients is far less defined. The identification of uncommon oncogene drivers is reshaping the diagnostic and therapeutic approach to NSCLC. The introduction of novel highly selective inhibitors is expanding the use of targeted therapies to rare and ultra-rare subsets of patients, further increasing the therapeutic armamentarium of advanced NSCLC.

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.

A harmonized meta-knowledgebase of clinical interpretations of somatic genomic variants in cancer

Precision oncology relies on accurate discovery and interpretation of genomic variants, enabling individualized diagnosis, prognosis and therapy selection. We found that six prominent somatic cancer variant knowledgebases were highly disparate in content, structure and supporting primary literature, impeding consensus when evaluating variants and their relevance in a clinical setting. We developed a framework for harmonizing variant interpretations to produce a meta-knowledgebase of 12,856 aggregate interpretations. We demonstrated large gains in overlap between resources across variants, diseases and drugs as a result of this harmonization. We subsequently demonstrated improved matching between a patient cohort and harmonized interpretations of potential clinical significance, observing an increase from an average of 33% per individual knowledgebase to 57% in aggregate. Our analyses illuminate the need for open, interoperable sharing of variant interpretation data. We also provide a freely available web interface (search.cancervariants.org) for exploring the harmonized interpretations from these six knowledgebases.

Targeting HER2 with Trastuzumab Deruxtecan: A Dose-Expansion, Phase I Study in Multiple Advanced Solid Tumors

HER2-targeted therapies are approved only for HER2-positive breast and gastric cancers. We assessed the safety/tolerability and activity of the novel HER2-targeted antibody-drug conjugate trastuzumab deruxtecan (T-DXd) in 60 patients with pretreated, HER2-expressing (IHC ≥ 1+), non-breast/non-gastric or HER2-mutant solid tumors from a phase I trial (NCT02564900). Most common (>50%) treatment-emergent adverse events (TEAE) were nausea, decreased appetite, and vomiting. Two drug-related TEAEs were associated with fatal outcomes. The confirmed objective response rate (ORR) was 28.3% (17/60). Median progression-free survival (PFS) was 7.2 [95% confidence interval (CI), 4.8-11.1] months. In HER2-mutant non-small cell lung cancer (NSCLC), ORR was 72.7% (8/11), and median PFS was 11.3 (95% CI, 8.1-14.3) months. Confirmed responses were observed in six tumor types, including HER2-expressing NSCLC, colorectal cancer, salivary gland cancer, biliary tract cancer, endometrial cancer, and HER2-mutant NSCLC and breast cancer. Results suggest T-DXd holds promise for HER2-expressing/mutant solid tumors. SIGNIFICANCE: T-DXd demonstrated promising activity in a heterogeneous patient population with heavily pretreated HER2-expressing or HER2-mutant solid tumors, especially HER2-mutant NSCLC. The safety profile was generally acceptable. Interstitial lung disease can be severe and requires prompt monitoring and intervention. Further research of T-DXd is warranted to address these unmet medical needs.See related commentary by Rolfo and Russo, p. 643.This article is highlighted in the In This Issue feature, p. 627.

HER2 exon 20 insertions in non-small-cell lung cancer are sensitive to the irreversible pan-HER receptor tyrosine kinase inhibitor pyrotinib

BACKGROUND

Effective targeted therapy for non-small-cell lung cancer (NSCLC) patients with human epidermal growth factor receptor 2 (HER2) mutations remains an unmet need. This study investigated the antitumor effect of an irreversible pan-HER receptor tyrosine kinase inhibitor, pyrotinib.

PATIENTS AND METHODS

Using patient-derived organoids and xenografts established from an HER2-A775_G776YVMA-inserted advanced lung adenocarcinoma patient sample, we investigated the antitumor activity of pyrotinib. Preliminary safety and efficacy of pyrotinib in 15 HER2-mutant NSCLC patients in a phase II clinical trial are also presented.

RESULTS

Pyrotinib showed significant growth inhibition of organoids relative to afatinib in vitro (P = 0.0038). In the PDX model, pyrotinib showed a superior antitumor effect than afatinib (P = 0.0471) and T-DM1 (P = 0.0138). Mice treated with pyrotinib displayed significant tumor burden reduction (mean tumor volume, -52.2%). In contrast, afatinib (25.4%) and T-DM1 (10.9%) showed no obvious reduction. Moreover, pyrotinib showed a robust ability to inhibit pHER2, pERK and pAkt. In the phase II cohort of 15 patients with HER2-mutant NSCLC, pyrotinib 400 mg resulted in a objective response rate of 53.3% and a median progression-free survival of 6.4 months.

CONCLUSION

Pyrotinib showed activity against NSCLC with HER2 exon 20 mutations in both patient-derived organoids and a PDX model. In the clinical trial, pyrotinib showed promising efficacy.

CLINICAL TRIAL REGISTRATION

NCT02535507.

Molecular Targets Beyond the Big 3

Lung cancer is a heterogeneous genomic disease. Smoking remains the primary cause. Genetic susceptibility and environmental exposures are responsible for 10% to 15% of cases. Targeted therapies improve survival in patients with tumors with oncogenic drivers. It is critical to expand our understanding of genetic alterations in non-small cell lung cancer to increase the available targeted therapies. Alterations beyond epidermal growth factor receptor (EGFR), ALK, and ROS1 exemplify lung cancer's complexity and the need for investments in precision therapy to extend patient survival and improve outcomes. This article covers genetic targets beyond EGFR, ALK and ROS1, their novel agents, challenges, and future directions.

Advanced Lung Adenocarcinoma Patient with ERBB2 Amplification Identified by Comprehensive Genomic Profiling Benefits from Trastuzumab

For non-small-cell lung cancer (NSCLC) patients without established actionable alterations in genes such as EGFR or ALK, options for targeted therapy remain limited in clinical practice. About 5% of lung adenocarcinoma patients have tumors with ERBB2 genetic alterations, with even fewer patients harboring ERBB2 amplification. Currently, clinical trials mainly use IHC, FISH, or mutation testing to identify potential responders to ERBB2-targeting agents. The use of next-generation sequencing (NGS) to detect ERBB2 alterations, including copy number variants, is rare. In this study, we present an EGFR- and ALK-negative advanced NSCLC case for which we conducted comprehensive tumor genomic profiling to identify potentially actionable alterations. The tumor harbored an ERBB2 amplification, and trastuzumab-based therapy resulted in an excellent response, with a necrotic regression of the patient's lung lesion. Although he developed brain metastasis four months after trastuzumab initiation, he survived for an additional period of eight months without local recurrence or other systemic metastasis. This case report shows that the use of comprehensive genetic testing enables the identification of rare actionable alterations in NSCLC patients without other options for targeted treatment.

The force of HER2 - A druggable target in NSCLC?

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

Novel drugs targeting EGFR and HER2 exon 20 mutations in metastatic NSCLC

Approximately 4% of epidermal growth factor receptor (EGFR)-mutated non-small cell lung cancer (NSCLC) present EGFR exon 20 in-frame insertions, accounting for 0.3 %-3.7 % of NSCLC. In addition, 2 %-4 % of patients with NSCLC harbor human epidermal growth factor receptor 2 gene (HER2) mutations, being the 90 % of them exon 20 insertions. These mutations confer intrinsic resistance to available EGFR tyrosine kinase inhibitors (TKIs) and anti-HER2 treatments, as they result in steric hindrance of the drug-binding pocket. Therefore, no targeted therapies have been approved for NSCLC patients with EGFR or HER2 exon 20- activating mutations to date and remain an unmet clinical need. Promising efforts to novel treatment development have been made. Early data provide encouraging activity of novel drugs targeting EGFR and HER2 mutations in metastatic NSCLC. In this review we will summarize all the data reported to date about these driver molecular alterations and potential targeted therapies.

Conformational Landscapes of HER2 Exon 20 Insertions Explain Their Sensitivity to Kinase Inhibitors in Lung Adenocarcinoma

INTRODUCTION

HER2 exon 20 insertion (ex20ins) is one of the most intractable problems in lung cancer. Most ex20ins are resistant to available EGFR or pan-HER tyrosine kinase inhibitors (TKIs), with the exception of a few mutants. However, the mechanism for TKI response and resistance of HER2 ex20ins remains poorly understood.

METHODS

Next-generation sequencing-based genomic profiling data of 4139 patients with lung cancer were interrogated for HER2 ex20ins. Structural modeling and molecular dynamics simulations of common HER2 ex20ins were carried out to provide insights into the mechanism of activation and response heterogeneity of ex20ins. Molecular docking was performed to predict affinity to TKIs. Therapeutic decisions for patients were made on the basis of the results of genomic profiling.

RESULTS

From 155 HER2-mutant lung cancer cases, Y772_A775dup and G778_P780dup were identified in 74 (47.7%) and 18 (11.6%) cases, respectively. Molecular dynamics simulations revealed that HER2 ex20ins led to ligand-independent kinase activation by changing the conformational landscape of HER2 kinase and restricting kinase conformation in the active state. G778_P780dup had a three-amino acid extension in the αC-β4 loop and retained the HER2-characteristic G776 and G778. Compared with Y772_A775dup, it had less restriction on kinase conformational sampling and higher affinity to afatinib, dacomitinib, pyrotinib, and poziotinib. Treating lung adenocarcinomas carrying G778_P780dup with these inhibitors led to sustained tumor responses in six of the 10 patients.

CONCLUSIONS

The kinase conformational landscape dictated by the length of the αC-β4 loop and residues at HER2 776 and 778 position explains TKI sensitivity in ex20ins. This finding could guide therapeutic decisions with currently available therapies and future drug development strategies.

Use of Ex Vivo Patient-Derived Tumor Organotypic Spheroids to Identify Combination Therapies for HER2 Mutant Non-Small Cell Lung Cancer

PURPOSE

Evaluating drug responses using primary patient-derived cells ex vivo represents a potentially rapid and efficient approach to screening for new treatment approaches. Here, we sought to identify neratinib combinations in HER2 mutant non-small cell lung cancer (NSCLC) patient xenograft-derived organotypic spheroids (XDOTS) using a short-term ex vivo system.

EXPERIMENTAL DESIGN

We generated two HER2-mutant NSCLC PDX models [DFCI359 (HER2 exon19 755_757LREdelinsRP) and DFCI315 (HER2 exon20 V777_G778insGSP)] and used the PDX tumors to generate XDOTS. Tumor spheroids were grown in a microfluidic device and treated ex vivo with neratinib-based drug combinations. Live/dead quantification was performed by dual-labeling deconvolution fluorescence microscopy. The most efficacious ex vivo combination was subsequently validated in vivo using the DFCI359 and DFCI315 PDXs and a HER2 ^YVMA genetically engineered mouse model.

RESULTS

Both neratinib and afatinib, but not gefitinib, induced cell death in DFCI359 XDOTS. The combinations of neratinib/trastuzumab and neratinib/temsirolimus enhanced the therapeutic benefit of neratinib alone in DFCI315 and DFCI359. The combination of neratinib and trastuzumab in vivo was more effective compared with single-agent neratinib or trastuzumab and was associated with more robust inhibition of HER2 and downstream signaling.

CONCLUSIONS

The XDOTS platform can be used to evaluate therapies and therapeutic combinations ex vivo using PDX tumors. This approach may accelerate the identification and clinical development of therapies for targets with no or few existing models and/or therapies.