Epidermal growth factor receptor exon 20 insertions in advanced lung adenocarcinomas: Clinical outcomes and response to erlotinib

Novel EGFR mutations in diffuse midline gliomas using cost-effective strategies: A report of 2 cases

Background

Diffuse midline gliomas (DMGs) are malignant tumors predominantly affecting children, often leading to poor outcomes. The 2021 World Health Organization classification identifies 3 subtypes of DMGs, all characterized by the loss of H3K27 trimethylation. Here, we report 2 cases of DMG with Epidermal Growth Factor Receptor (EGFR) mutations within exon 20, contributing to the understanding of the molecular complexity of these pediatric brain tumors.

Methods

An economical immunohistochemical panel was designed to aid in the diagnosis of most DMGs in resource-constrained regions. Sanger sequencing was employed to identify rare EGFR mutations in exon 20 of 2 cases.

Results

Molecular analyses of 2 cases of DMG revealed novel EGFR mutations within exon 20. These mutations were identified using cost-effective diagnostic approaches. The presence of EGFR mutations expands the molecular landscape of DMGs and highlights the genetic heterogeneity within this tumor entity.

Conclusions

These findings underscore the molecular heterogeneity of DMGs and the significance of identifying novel mutations, such as EGFR mutations in exon 20. Further research into the molecular mechanisms underlying DMGs is warranted to advance therapeutic strategies and improve outcomes for pediatric patients.

First-in-human phase I study of BEBT-109 in previously treated EGFR exon 20 insertion-mutated advanced non-small cell lung cancer

BACKGROUND

BEBT-109 is an oral pan-mutant-selective inhibitor of epidermal growth factor receptor (EGFR) that demonstrated promising antitumor potency in preclinical models.

METHODS

This first-in-human study was a single-arm, open-label, two-stage study. Phase Ia dose-escalation study evaluated the safety and pharmacokinetics of BEBT-109 in 11 patients with EGFR T790M-mutated advanced non-small cell lung cancer (aNSCLC). Phase Ib dose-expansion study evaluated the safety and efficacy of BEBT-109 in 18 patients with EGFR exon 20 insertion (ex20ins)-mutated treatment-refractory aNSCLC. The primary outcomes were adverse events and antitumor activity. Clinical trial registration number CTR20192575.

FINDINGS

The phase Ia study demonstrated no dose-limiting toxicity, no observation of the maximum tolerated dose, and no new safety signals with BEBT-109 in the dose range of 20-180 mg/d, suggesting that BEBT-109 had an acceptable safety profile among patients with EGFR T790M-mutated aNSCLC. Plasma pharmacokinetics of BEBT-109 showed a dose-proportional increase in the area under the curve and maximal concentration, with no significant drug accumulation. The dose-expansion study demonstrated that BEBT-109 treatment was tolerable across the three dose levels. The three most common treatment-related adverse events were diarrhea (100%; 22.2% ≥Grade 3), rash (66.7%; 5.6% ≥Grade 3), and anemia (61.1%; 0% ≥Grade 3). The objective response rate was 44.4% (8 of 18). Median progression-free survival was 8.0 months (95% confidence intervals, 1.33-14.67).

CONCLUSION

Preliminary findings showed that BEBT-109 had an acceptable safety profile and favorable antitumor activity in patients with refractory EGFR ex20ins-mutated aNSCLC.

FUNDING

National Natural Science Foundation of China.

Current status and breakthroughs in treating advanced non-small cell lung cancer with EGFR exon 20 insertion mutations

Recently, targeted therapy and immunotherapy have emerged as effective treatment options for non-small cell lung cancer (NSCLC). This progress has been facilitated by the rapid development of diagnostic and therapeutic technologies and the continuous research and development of new drugs, leading to a new era in precision medicine for NSCLC. This is a breakthrough for patients with common mutations in the human epidermal growth factor receptor (EGFR) gene in NSCLC. Consequently, the use of targeted drugs has significantly improved survival. Nevertheless, certain rare genetic mutations are referred to as EGFR exon 20 insertion (ex20ins) mutations, which differ in structure from conventional EGFR gene mutations, namely, exon 19 deletion mutations (19-Del) and exon 21 point mutations. Owing to their distinct structural characteristics, patients harboring these EGFR ex20ins mutations are unresponsive to traditional tyrosine kinase inhibitor (TKI) therapy. This particular group of patients did not fall within the scope of their applicability. However, the activating A763_Y764insFQEA mutation elicits a more pronounced response than mutations in the near and far regions of the C-helix immediately following it and should, therefore, be treated differently. Currently, there is a lack of effective treatments for EGFR ex20ins mutations NSCLC. The efficacy of chemotherapy has been relatively favorable, whereas the effectiveness of immunotherapy remains ambiguous owing to inadequate clinical data. In addition, the efficacy of the first- and second-generation targeted drugs remains limited. However, third-generation and novel targeted drugs have proven to be effective. Although novel EGFR-TKIs are expected to treat EGFR ex20ins mutations in patients with NSCLC, they face many challenges. The main focus of this review is on emerging therapies that target NSCLC with EGFR ex20ins and highlight major ongoing clinical trials while also providing an overview of the associated challenges and research advancements in this area.

Clinical outcomes in patients with non-small cell lung cancer harboring EGFR Exon20 in-frame insertions in the near-loop and far-loop: Results from LC-SCRUM-Asia

OBJECTIVES

In this study, we explored the clinical outcomes of non-small cell lung cancer (NSCLC) patients with EGFR Exon20 in-frame insertions (Exon20ins), and the impact of the location of Exon20ins on these clinical outcomes.

MATERIALS AND METHODS

The efficacies of current systemic therapies in NSCLC patients harboring Exon20ins were investigated using a large-scale clinico-genomic database of LC-SCRUM-Asia, and compared with that of amivantamab in the CHRYSALIS trial.

RESULTS

Of the 11,397 patients enrolled in LC-SCRUM-Asia, Exon20ins were detected in 189 patients (1.7 %). Treatment with classical EGFR tyrosine-kinase inhibitors (classical TKIs) was associated with a significantly shorter progression-free survival (PFS) in NSCLC patients with Exon20ins as compared with Exon19 deletions and L858R. Post platinum-based chemotherapy, classical TKIs and immune checkpoint inhibitors (ICIs) were associated with a shorter PFS than with docetaxel in patients with Exon20ins (HR [95 % CI]; TKIs vs docetaxel, 2.16 [1.35-3.46]; ICIs vs docetaxel, 1.49 [1.21-1.84]). Patients treated with amivantamab in the CHRYSALIS trial showed a risk reduction in PFS and overall survival as compared with LC-SCRUM-Asia patients treated with docetaxel, classical TKIs, or ICIs. Among the 189 patients, Exon20ins were classified as near-loop or far-loop insertions in 115 (61 %) and 56 (30 %) patients, respectively. Treatment with osimertinib was associated with a longer PFS in patients with Exon20ins in near-loop as compared with far-loop (median, 5.6 vs. 2.0 months; HR [95 % CI], 0.22 [0.07-0.64]).

CONCLUSIONS

After platinum-based chemotherapy, classical TKIs and ICIs are less effective in NSCLC patients with Exon20ins, and amivantamab may be a promising targeted therapy. There is a possibility that the location of Exon20ins has an impact on the efficacy of TKIs.

The association of EGFR amplification with aberrant exon 20 insertion report using the cobas EGFR Mutation Test v2

Determining the exact type of epidermal growth factor receptor (EGFR) exon 20 insertion (ex20ins) mutation in lung cancer has become important. We found that not all ex20ins mutations reported by cobas EGFR test v2 could be validated by Sanger sequencing even using surgical specimens with high tumor contents. This study aimed to validate the ex20ins results reported by the cobas test and to determine whether there were clinicopathological factors associated with aberrant cobas ex20ins report. In total, 123 cobas-reported cases with ex20ins were retrospectively collected and validated by Sanger sequencing and Idylla assay. Clinicopathological features between ex20ins cobas+/Sanger+ group (n = 71) and cobas+/Sanger- group (n = 52) were compared. The Idylla assay detected ex20ins in 82.6% of cobas+/Sanger+ cases but only in 4.9% of cobas+/Sanger- cases. The cobas+/Sanger- group was significantly associated with higher tumor contents, poorly differentiated patterns, tumor necrosis, and a lower internal control cycle threshold value reported by the Idylla which suggesting the presence of increased EGFR gene copy numbers. EGFR fluorescence in situ hybridization (FISH) revealed the majority of cobas+/Sanger- group had EGFR high copy number gain (16%) or amplification (76%) according to the Colorado criteria. Among cases reported to have concomitant classic EGFR and ex20ins mutations by the cobas, the classic EGFR mutations were all detected by Sanger sequencing and Idylla, while the ex20ins mutations were undetected by Sanger sequencing (0%) or rarely reported by Idylla assay (3%). FISH revealed high EGFR copy number gain (17.9%) and amplification (79.5%) in cases reported having concomitant classic EGFR and ex20ins mutations by the cobas. This study demonstrated an unusually high frequency of EGFR amplification in cases with aberrant cobas ex20ins report which could not be validated by Sanger sequencing or Idylla assay. Ex20ins reported by the cobas test should be validated using other methods especially those reported having concomitant ex20ins and classic EGFR mutations.

Drug Resistance and Novel Targets for Cancer Therapy: An Overview of Recent Findings

The complex nature of cancer cells poses a challenge to the scientific community [...].

A phase 2 trial combining afatinib with cetuximab in patients with EGFR exon 20 insertion-positive non-small cell lung cancer

BACKGROUND

Epidermal growth factor receptor (EGFR) exon 20 insertion (ex20ins) mutations are the third most common EGFR mutations in patients with non-small cell lung cancer (NSCLC) and are associated with primary resistance to EGFR tyrosine kinase inhibitors (TKIs). There is evidence of activity of combining EGFR TKIs with monoclonal antibodies. This study reports on the efficacy and safety of afatinib in combination with cetuximab.

METHODS

In this single-arm phase 2 trial, patients with advanced NSCLC harboring an EGFR ex20ins mutation were treated with afatinib 40 mg once daily in combination with cetuximab 500 mg/m2 every 2 weeks. The primary end point was disease control rate (DCR) at 18 weeks of treatment.

RESULTS

Thirty-seven patients started treatment, with a median age of 65 years (range, 40-80 years), 78% female, and 95% White. The study achieved its primary end point with a DCR of 54% at 18 weeks, an overall response rate (ORR) of 43%, and a 32% confirmed ORR. Best responses were partial (n = 16), stable (n = 16), progressive disease (n = 2), or not evaluable (n = 3). Median progression-free survival was 5.5 months (95% CI, 3.7-8.3 months) and median overall survival was 16.8 months (95% CI, 10.7-25.8 months). The most common treatment-related adverse events (TRAEs) were diarrhea (70%), rash (65%), dry skin (59%), paronychia (54%), and erythema (43%). Grade 3 TRAEs were reported in 54% of all patients.

CONCLUSIONS

Combination treatment with afatinib and cetuximab demonstrated antitumor activity with a DCR of 54% at 18 weeks and a 32% confirmed ORR. Toxicity was significant, although manageable, after dose reduction.

Transcription factor ZNF263 enhances EGFR-targeted therapeutic response and reduces residual disease in lung adenocarcinoma

EGF receptor (EGFR) tyrosine kinase inhibitors (TKIs) have achieved clinical success in lung adenocarcinoma (LUAD). However, tumors often show profound but transient initial response and then gain resistance. We identify transcription factor ZNF263 as being significantly decreased in osimertinib-resistant or drug-tolerant persister LUAD cells and clinical residual tumors. ZNF263 overexpression improves the initial response of cells and delays the formation of persister cells with osimertinib treatment. We further show that ZNF263 binds and recruits DNMT1 to the EGFR gene promoter, suppressing EGFR transcription with DNA hypermethylation. ZNF263 interacts with nuclear EGFR, impairing the EGFR-STAT5 interaction to enhance AURKA expression. Overexpressing ZNF263 also makes tumor cells with wild-type EGFR expression or refractory EGFR mutations more susceptible to EGFR inhibition. More importantly, lentivirus or adeno-associated virus (AAV)-mediated ZNF263 overexpression synergistically suppresses tumor growth and regrowth with osimertinib treatment in xenograft animal models. These findings suggest that enhancing ZNF263 may achieve complete response in LUAD with EGFR-targeted therapies.

First report of furmonertinib as a first-line treatment in advanced lung adenocarcinoma patients harboring EGFR exon 20 insertion mutations after the kinase domain αC-helix: Two case reports and a literature review

RATIONALE

Many studies have shown that first- and second-generation epidermal growth factor receptor tyrosine kinase inhibitors are less effective in patients with epidermal growth factor receptor (EGFR) exon 20 insertion (ex20ins) mutations. The efficacy of third-generation epidermal growth factor receptor tyrosine kinase inhibitors is still under investigation. Although new targeted tyrosine kinase inhibitors and monoclonal antibody-based agents have made significant advances in the treatment of epidermal growth factor receptor exon 20 insertion (EGFR ex20ins) mutation, the efficacy of these novel agents is not quite satisfactory. Platinum- and pemetrexed-based chemotherapy remains the standard first-line treatment for patients harboring EGFR ex20ins mutation.

PATIENT CONCERNS

We report for the first time 2 Chinese patients diagnosed with advanced lung adenocarcinoma with EGFR ex20ins mutations after analysis of the αC-helix sequence by next-generation sequencing. Both patients were treated with furmonertinib as the first-line therapy.

INTERVENTIONS

The first case included a 38-year-old female who had an EGFR ex20ins mutation (p.S768_D770dupSVD). After 1 month of treatment with furmonertinib, her symptoms of pain and cough were significantly alleviated. She achieved a partial response according to response evaluation criteria in solid tumors.[1] The final progression-free survival was 8.13 months. The second case included a 40-year-old male who had an EGFR ex20ins mutation (p.N771_P772insVal). He had a good response to furmonertinib and exhibited stable disease according to response evaluation criteria in solid tumors with a progression-free survival of 10.90 months.

OUTCOMES

Both patients experienced significant improvement in symptoms and prolonged survival after furmonertinib was used as first-line treatment. Side effects were limited but manageable.

CONCLUSION

The present study indicates that furmonertinib may be a first-line treatment option for patients with non-small cell lung cancer harboring EGFR ex20ins mutation.

Epidemiological characteristics and therapeutic advances of EGFR exon 20 insertion mutations in non-small cell lung cancer

The third most prevalent type of epidermal growth factor receptor (EGFR) mutation, EGFR exon 20 insertions (EGFRex20ins), involves 2%-12% of all cases of EGFR-positive non-small cell lung cancer (NSCLC). Approximately 90% of the mutations occur within the loop structure region, and the most frequently reported subtypes are A767_V769dup and S768_D770dup, which together account for almost 50% of instances. Apart from the unique subtype of A763_Y764insFQEA, NSCLCs with EGFRex20ins are resistant to approved EGFR tyrosine kinase inhibitors (TKIs) and are also insensitive to chemotherapy or immunotherapy. A new modality of treatment for NSCLC patients with EGFRx20ins has been established with the approval of mobocertinib and amivantamab. There are also numerous novel targeted treatments for NSCLC with EGFRex20ins in development, which are anticipated to improve this patient population's survival even further. This review provides a reference for the clinical management of these patients by summarizing the most recent epidemiological, and clinicopathological characteristics, diagnostic techniques, and therapeutic advances of EGFRex20ins in NSCLC.

EGFR exon20 insertion mutations in non-small cell lung cancer: Clinical implications and recent advances in targeted therapies

The advent of targeted therapies for oncogenic mutations has led to a major paradigm shift in the management of non-small cell lung cancer (NSCLC). Molecular targets, such as epidermal growth factor receptor (EGFR)-activating mutations in the region of exons 18 through 21 are the most common oncogenic driver in NSCLC. Classical activating mutations, such as in-frame deletions in exon 19 and point mutations in exon 21 (L858R), are strong predictors for good clinical response to the approved EGFR-tyrosine kinase inhibitors (EGFR-TKIs). However, low frequency mutations occurring within exon 20 (ex20ins) have poorer responses to first/second generation EGFR-TKIs. Moreover, patients with NSCLC harboring EGFR ex20ins are known to have poorer prognosis than those with other EGFR-TKI sensitive mutations, leading to unmet clinical need of novel specific therapeutic options. Rapid changes in molecular diagnostics identifying specific causes have hastened the translation of diagnostic recommendations into clinical practice. Emergence of treatment strategies targeting EGFR ex20ins, such as newer EGFR-TKIs with increased specificity and novel approaches using bispecific monoclonal antibodies, may hold promising therapeutic options in the near future. In this review, we describe the structural, molecular characteristics, and detection strategies of EGFR ex20ins mutations and summarize the latest clinical data on approved treatments and emerging therapies for patients with NSCLC harboring EGFR ex20ins mutations. Further, we will discuss the response heterogeneity of ex20ins mutations to new drugs and acquired drug resistance mechanisms.

Real-World Response and Outcomes in Patients With NSCLC With EGFR Exon 20 Insertion Mutations

Introduction

This study describes treatment patterns and outcomes in patients with NSCLC with EGFR exon 20 insertions (EGFRex20ins) in the United States.

Methods

The Flatiron Health electronic health record database was used to select three cohorts among patients diagnosed with NSCLC with EGFRex20ins (January 1, 2011-February 29, 2020): (1) first-line (1L) or patients receiving 1L therapy after documented EGFRex20ins; (2) second or later-line (≥2L) or patients receiving ≥2L therapy after documented EGFRex20ins; and (3) ≥2L postplatinum trial-aligned, or ≥2L patients previously treated with platinum chemotherapy whose baseline characteristics aligned with key eligibility criteria (initiating new treatment after documented EGFRex20ins and ≥1 previous treatment excluding mobocertinib or amivantamab) of the mobocertinib trial NCT02716116. Real-world end points were confirmed overall response rate, overall survival, and progression-free survival.

Results

Of 237 patients with EGFRex20ins-mutated NSCLC, 129 and 114 patients were included in the 1L and ≥2L cohorts, respectively. In 1L patients, platinum chemotherapy plus nonplatinum chemotherapy (31.0%) and EGFR tyrosine kinase inhibitors (28.7%) were the most common regimens. In ≥2L patients, immuno-oncology monotherapy (28.1%) and EGFR tyrosine kinase inhibitors (17.5%) were the most common index treatments. For any 1L, ≥2L, and ≥2L postplatinum trial-aligned patients, the confirmed overall response rate was 18.6%, 9.6%, and 14.0%, respectively; the median overall survival was 17.0, 13.6, and 11.5 months; the median progression-free survival was 5.2, 3.7, and 3.3 months, respectively.

Conclusions

The outcomes for patients with NSCLC with EGFRex20ins were poor. This real-world study provides a benchmark on treatment outcomes in this patient population and highlights the unmet need for improved therapeutic options.

Structural Mechanism and Inhibitors Targeting EGFR Exon 20 Insertion (Ex20ins) Mutations

Epidermal growth factor receptor (EGFR) targeted therapy is one of the most important and effective strategies to combat EGFR mutant nonsmall-cell lung cancer (NSCLC). However, a substantial number of patients bearing EGFR exon 20 insertion (Ex20ins) mutations respond poorly to common EGFR targeted therapies. This clinical need remained unmet until recently, when the EGFR Ex20ins mutation inhibitor mobocertinib was approved by the FDA. Despite this progress, the structural mechanisms of EGFR Ex20ins mutation resistance and characterization of inhibitor binding modes have not been systematically summarized. Herein, we analyze the structural mechanisms for ligand binding and resistance and summarize recent developments for the reported inhibitors of EGFR Ex20ins mutations. Furthermore, this Perspective aims to provide insights for the design of the next generation of EGFR Ex20ins inhibitors.

Discovery of YK-029A, a novel mutant EGFR inhibitor targeting both T790 M and exon 20 insertion mutations, as a treatment for NSCLC

Although traditional EGFR-TKIs have advanced the treatment landscape of NSCLC with sensitive driver mutations (del19 or L858R), some NSCLC patients with EGFR exon 20 insertion mutations have been left with few effective therapies. The development of novel TKIs is still in progress. Herein, we describe the structure-guided design of a novel selective and orally bioavailable inhibitor, YK-029A, which could overcome both the T790 M mutations and exon 20 insertion of EGFR. YK-029A inhibited EGFR signaling, suppressed sensitive mutations and ex20ins of EGFR-driven cell proliferation, and was largely effective with oral administration in vivo. Furthermore, YK-029A exhibited significant antitumor activity in EGFRex20ins-driven patients-derived xenograft (PDX) models, preventing tumor progression or causing tumor regression at well-tolerated dosages. Based on the outcomes of preclinical efficacy and safety studies, YK-029A will enter phase Ⅲ clinical trials for the treatment of EGFRex20ins NSCLC.

Comparative Effectiveness of Mobocertinib and Standard of Care in Patients with NSCLC with EGFR Exon 20 Insertion Mutations: An Indirect Comparison

INTRODUCTION

Mobocertinib is a novel, first-in-class, irreversible, oral epidermal growth factor receptor (EGFR) tyrosine kinase inhibitor (TKI) designed to selectively target in-frame EGFR exon 20 insertions (ex20ins). Comparative effectiveness data for mobocertinib versus real-world treatments are lacking in this rare population. This study compared data for mobocertinib reported in a Phase I/II single-arm clinical trial with an external control group consisting of patients who received available treatment in the real-world setting in the United States (US).

MATERIALS AND METHODS

The mobocertinib group included platinum-pretreated patients with advanced EGFR ex20ins non-small cell lung cancer (NSCLC) receiving mobocertinib 160 mg QD in an ongoing, single-arm, phase 1/2 clinical trial (NCT02716116; n = 114). The real-world data (RWD) group included platinum-pretreated patients with advanced EGFR ex20ins-mutant NSCLC from the Flatiron Health database (n = 50). Inverse probability treatment weighting based on the propensity score method controlled for potential confounding between groups. Confirmed overall response rate (cORR), progression-free survival (PFS), and overall survival (OS) were compared between groups.

RESULTS

After weighting, baseline characteristics were balanced. Patients in the RWD group received EGFR TKI (20 %), immuno-oncology therapy (40 %), or any regimens containing chemotherapy (40 %) in the second- or later-line setting. In the mobocertinib and RWD groups, respectively, cORR was 35.1 % and 11.9 % (odds ratio: 3.75 [95 % confidence interval (CI): 2.05, 6.89]); median PFS was 7.3 and 3.3 months (hazard ratio [HR]: 0.57 [95 % CI: 0.36, 0.90]); and median OS was 24.0 and 12.4 months (HR: 0.53 [95 % CI: 0.33, 0.83]) after weighting.

DISCUSSION

Mobocertinib showed substantially improved outcomes versus an external control group using available therapies in platinum-pretreated patients with EGFR ex20ins-mutant NSCLC. In the absence of comparative evidence from randomized trials, these findings help elucidate potential benefits of mobocertinib in this rare population.

Rare molecular subtypes of lung cancer

Oncogenes that occur in ≤5% of non-small-cell lung cancers have been defined as 'rare'; nonetheless, this frequency can correspond to a substantial number of patients diagnosed annually. Within rare oncogenes, less commonly identified alterations (such as HRAS, NRAS, RIT1, ARAF, RAF1 and MAP2K1 mutations, or ERBB family, LTK and RASGRF1 fusions) can share certain structural or oncogenic features with more commonly recognized alterations (such as KRAS, BRAF, MET and ERBB family mutations, or ALK, RET and ROS1 fusions). Over the past 5 years, a surge in the identification of rare-oncogene-driven lung cancers has challenged the boundaries of traditional clinical grade diagnostic assays and profiling algorithms. In tandem, the number of approved targeted therapies for patients with rare molecular subtypes of lung cancer has risen dramatically. Rational drug design has iteratively improved the quality of small-molecule therapeutic agents and introduced a wave of antibody-based therapeutics, expanding the list of actionable de novo and resistance alterations in lung cancer. Getting additional molecularly tailored therapeutics approved for rare-oncogene-driven lung cancers in a larger range of countries will require ongoing stakeholder cooperation. Patient advocates, health-care agencies, investigators and companies with an interest in diagnostics, therapeutics and real-world evidence have already taken steps to surmount the challenges associated with research into low-frequency drivers.

Amivantamab-Vmjw: A Novel Treatment for Patients with NSCLC Harboring EGFR Exon 20 Insertion Mutation after Progression on Platinum-Based Chemotherapy

OBJECTIVE

This study is a comprehensive review of the clinical pharmacology, pharmacokinetics, efficacy, safety, and clinical applicability of amivantamab-vmjw for metastatic non-small cell lung cancer (NSCLC) with epidermal growth factor receptor (EGFR) exon 20 insertion (exon20ins) mutation.

DATA SYNTHESIS

The literature search to identify clinical trials returned only the CHRYSALIS phase 1 study. In a phase I trial, amivantamab-vmjw was associated with an overall response rate (ORR) of 40% (95% CI, 29-51) in the EGFR exon20ins NSCLC patient population (n = 81) after platinum-based chemotherapy. There were 3 complete responses (CRs) and 29 partial responses (PRs). The median duration of response (DOR) was 11.1 months (95% CI, 6.9-not reached; NR). The median progression-free survival (PFS) was 8.3 months (95% CI, 6.5-10.9), and overall survival (OS) was 22.8 months (95% CI, 14.6-NR).

APPLICATION TO CLINICAL PRACTICE

This review summarizes the pharmacology, clinical evidence, and use of amivantamab-vmjw for patients with locally advanced or metastatic NSCLC with EGFR exon20ins mutation.

CONCLUSION

The FDA approval of amivantamab-vmjw, the first bispecific antibody to target the exon20ins mutation, represents an important advancement in the treatment of patients with NSCLC with limited effective treatment options. The initial findings of the CHRYSALIS trial demonstrate an overall tumor response benefit with an acceptable safety profile.

Osimertinib in NSCLC With Atypical EGFR-Activating Mutations: A Retrospective Multicenter Study

Introduction

EGFR mutations drive a subset of NSCLC. Patients harboring the common EGFR mutations, deletion of exon 19 and L858R, respond well to osimertinib, a third-generation tyrosine kinase inhibitor. Nevertheless, the effect of osimertinib on NSCLC with atypical EGFR mutations is not well described. This multicenter retrospective study evaluates the efficacy of osimertinib among patients with NSCLC harboring atypical EGFR mutations.

Methods

Patients with metastatic NSCLC treated with osimertinib, harboring at least one atypical EGFR mutation, excluding concurrent deletion of exon 19, L858R, or T790M mutations, from six U.S. academic cancer centers were included. Baseline clinical characteristics were collected. The primary end point was the time to treatment discontinuation (TTD) of osimertinib. Objective response rate by the Response Evaluation Criteria in Solid Tumors version 1.1 was also assessed.

Results

A total of 50 patients with NSCLC with uncommon EGFR mutations were identified. The most frequent EGFR mutations were L861Q (40%, n = 18), G719X (28%, n = 14), and exon 20 insertion (14%, n = 7). The median TTD of osimertinib was 9.7 months (95% confidence interval [CI]: 6.5-12.9 mo) overall and 10.7 months (95% CI: 3.2-18.1 mo) in the first-line setting (n = 20). The objective response rate was 31.7% (95% CI: 18.1%-48.1%) overall and 41.2% (95% CI: 18.4%-67.1%) in the first-line setting. The median TTD varied among patients with L861Q (17.2 mo), G719X (7.8 mo), and exon 20 insertion (1.5 mo) mutations.

Conclusions

Osimertinib has activity in patients with NSCLC harboring atypical EGFR mutations. Osimertinib activity differs by the type of atypical EGFR-activating mutation.

TAS2940, a novel brain-penetrable pan-ERBB inhibitor, for tumors with HER2 and EGFR aberrations

Genetic alterations in human epidermal growth factor receptor type 2 (HER2)/epidermal growth factor receptor (EGFR) are commonly associated with breast and lung cancers and glioblastomas. Cancers with avian erythroblastosis oncogene B (ERBB) deregulation are highly metastatic and can cause primary brain tumors. Currently, no pan-ERBB inhibitor with remarkable brain penetration is available. Here, TAS2940, a novel irreversible pan-ERBB inhibitor with improved brain penetrability, was evaluated for its efficacy against several ERBB aberrant cancer models. The selectivity of TAS2940 was evaluated by enzymatic kinase assays. The inhibitory effects of TAS2940 against ERBB genetic alterations were examined using MCF10A cells expressing various HER2 or EGFR mutations and other generic cell lines harboring deregulated ERBB expression. In vivo efficacy of TAS2940 was examined following oral treatment in subcutaneous or intracranial xenograft cancer models. TAS2940 was highly potent against cells harboring HER2/EGFR alterations. TAS2940 could selectively inhibit phosphorylation of targets and the growth of cancer cells with ERBB aberrations in vitro. TAS2940 also inhibited tumor growth in xenograft mouse models with ERBB aberrations: HER2 amplification, HER2/EGFR exon 20 insertions, and EGFR vIII mutation. TAS2940 was effective in the intracranial xenograft models of HER2/EGFR cancers and improved the survival of these mice. TAS2940 has promising therapeutic effects in preclinical study against cancers harboring HER2/EGFR mutations, especially metastatic and primary brain tumors. Our results highlight potential novel strategies against lung cancers with brain metastases harboring HER2/EGFR exon 20 insertions and glioblastomas with EGFR aberrations.

Advances in the management of non-small-cell lung cancer harbouring EGFR exon 20 insertion mutations

Epidermal growth factor receptor (EGFR) mutation is one of the key oncogenic mutations in non-small-cell lung cancer with adenocarcinoma histology. Exon 19 deletions and exon 21 L858R substitutions account for 90%, while EGFR exon 20 insertions constitute 4-10% of EGFR mutations and are the third most prevalent activating EGFR mutations. EGFR exon 20 insertions are associated with decreased sensitivity to EGFR tyrosine kinase inhibitors and, until recently, effective targeted therapy against these tumours remained an unmet clinical need and chemotherapy was the only treatment of choice available. The approval of amivantamab and mobocertinib for patients who have progressed after chemotherapy represents an important step forward in the management of these patients. Here in this review, we summarize the epidemiology, structure and the tumour microenvironment of EGFR exon 20 insertion and also review the systemic treatments, including targeted therapies and ongoing clinical trials in EGFR exon 20 insertion mutations, as well as detection methods for EGFR exon 20 insertion. Lastly, resistant mechanisms and future directions are addressed.

Structure-Guided Strategies of Targeted Therapies for Patients with EGFR-Mutant Non-Small Cell Lung Cancer

Oncogenic mutations within the EGFR kinase domain are well-established driver mutations in non-small cell lung cancer (NSCLC). Small-molecule tyrosine kinase inhibitors (TKIs) specifically targeting these mutations have improved treatment outcomes for patients with this subtype of NSCLC. The selectivity of these targeted agents is based on the location of the mutations within the exons of the EGFR gene, and grouping mutations based on structural similarities has proved a useful tool for conceptualizing the heterogeneity of TKI response. Structure-based analysis of EGFR mutations has influenced TKI development, and improved structural understanding will inform continued therapeutic development and further improve patient outcomes. In this review, we summarize recent progress on targeted therapy strategies for patients with EGFR-mutant NSCLC based on structure and function analysis.

Discovery of mobocertinib, a potent, oral inhibitor of EGFR exon 20 insertion mutations in non-small cell lung cancer

In the treatment of non-small cell lung cancer (NSCLC), patients harboring exon 20 insertion mutations in the epidermal growth factor receptor (EGFR) gene (EGFR) have few effective therapies because this subset of mutants is generally resistant to most currently approved EGFR inhibitors. This report describes the structure-guided design of a novel series of potent, irreversible inhibitors of EGFR exon 20 insertion mutations, including the V769_D770insASV and D770_N771insSVD mutants. Extensive structure-activity relationship (SAR) studies led to the discovery of mobocertinib (compound 21c), which inhibited growth of Ba/F3 cells expressing the ASV insertion with a half-maximal inhibitory concentration of 11 nM and with selectivity over wild-type EGFR. Daily oral administration of mobocertinib induced tumor regression in a Ba/F3 ASV xenograft mouse model at well-tolerated doses. Mobocertinib was approved in September 2021 for the treatment of adult patients with advanced NSCLC with EGFR exon 20 insertion mutations with progression on or after platinum-based chemotherapy.

Targeting exon 20 insertion mutations in lung cancer

PURPOSE OF REVIEW

The application of tyrosine kinase inhibitor (TKI) has successfully changed the standard of care in epidermal growth factor receptor ( EGFR ) positive non-small cell lung cancer. However, clinical survivals for patients with EGFR exon 20 insertions have failed to improve over the long period and the mutation appeared resistant to EGFR -TKIs. This overview focused on the current treatment strategies, summarized the emerging regimens for patients with EGFR exon 20 insertions, and demonstrated historical challenges and future development.

RECENT FINDING

Current clinical trials suggested that several regimens selectively-targeted EGFR exon 20 insertions presented potent antitumor activity, like mobocertinib and the bispecific anti- EGFR-MET monoclonal antibody amivantamab and were approved by Food and Drug Administration (FDA) in patients progressed beyond first-line treatment. Novel treatments, including DZD9008, CLN-081, revealed modest clinical efficacy as well and clinical trials are underway, which may lead to improvement of survival outcomes.

SUMMARY

Recent clinical evidence indicates that targeted therapies could improve survival benefits to some extent. More efforts on drug development are underway to bring higher response rates both extracranial and intracranial, sustained clinical remission, and better survival benefits.

Review of novel and supplemental approvals of the targeted cancer drugs by the Food and Drug Administration in 2021

OBJECTIVE

This review aims to present the most recent results from clinical trials of targeted cancer drugs that led to the Food and Drug Administration approval in 2021 and reflect the changing treatment landscape of solid malignancies.

DATA SOURCES

Novel approvals and supplemental approvals in 2021 were retrieved from the official web page of the Food and Drug Administration (Drugs@FDA). This review did not include approvals for generics, biosimilars, imaging, and diagnostics agents.

DATA SUMMARY

This review included 10 novel drugs approved for 11 indications and 10 already-approved drugs approved for 21 indications by the Food and Drug Administration in 2021. Novel approvals mainly were related to treating an orphan disease. In addition, one-third of the supplemental approvals were given for neoadjuvant or adjuvant treatment, while the number of indications for each tumor site was as follows: gastrointestinal (7), genitourinary (5), skin (3), lung (2), breast (2), thyroid (1), and cervix (1).

CONCLUSIONS

Targeted cancer treatments are gaining more importance than ever in treating malignant diseases. As the approval of targeted cancer drugs provides a possibility for patients and this trend is expected to continue in the future, it remains vital for healthcare providers to stay up-to-date with newer therapeutic options.

Kinase Inhibitors Involved in the Regulation of Autophagy: Molecular Concepts and Clinical Implications

All cells and intracellular components are remodeled and recycled in order to replace the old and damaged cells. Autophagy is a process by which damaged, and unwanted cells are degraded in the lysosomes. There are three different types of autophagy: macroautophagy, microautophagy, and chaperone-mediated autophagy. Autophagy has an effect on adaptive and innate immunity, suppression of any tumour, and the elimination of various microbial pathogens. The process of autophagy has both positive and negative effects, and this pertains to any specific disease or its stage of progression. Autophagy involves various processes which are controlled by various signaling pathways, such as Jun N-terminal kinase, GSK3, ERK1, Leucine-rich repeat kinase 2, and PTEN-induced putative kinase 1 and parkin RBR E3. Protein kinases are also important for the regulation of autophagy as they regulate the process of autophagy either by activation or inhibition. The present review discusses the kinase catalyzed phosphorylated reactions, the kinase inhibitors, types of protein kinase inhibitors and their binding properties to protein kinase domains, the structures of active and inactive kinases, and the hydrophobic spine structures in active and inactive protein kinase domains. The intervention of autophagy by targeting specific kinases may form the mainstay of treatment of many diseases and lead the road to future drug discovery.

Emerging therapies for non-small cell lung cancer harboring EGFR exon 20 insertion mutations: narrative review

Background and Objective

Epidermal growth factor receptor (EGFR) exon 20 insertion mutations (ex20ins) are uncommon in non-small cell lung cancer (NSCLC). These mutations are generally resistant to first-generation EGFR tyrosine kinase inhibitors, unlike common EGFR mutations, including exon 19 deletions or exon 21 L858R point mutation. The development of effective targeted therapies for NSCLC harboring EGFR ex20ins has been eagerly anticipated over the years. Recently, the therapeutic landscape of this subgroup of EGFR-mutant NSCLC patients has rapidly evolved due to the emergence of new drugs. In 2021, several novel agents, such as amivantamab and mobocertinib, have been approved by the US Food and Drug Administration for patients with advanced platinum-resistant NSCLC harboring EGFR ex20ins. In this review, we mainly focus on emerging therapies targeting NSCLC with EGFR ex20ins, as well as important ongoing clinical trials.

Methods

Searches were conducted in PubMed and supplemented with recent conference proceedings in November 30th, 2021.

Key Content and Findings

Several novel emerging therapies showed favorable safety profile and promising anti-tumor activity in NSCLC patients with EGFR ex20ins in recent several clinical trials.

Conclusions

There is still room for improvement in the treatment results of NSCLC harboring EGFR ex20ins. Future research should focus on the molecular heterogeneity in the size and location of distinct EGFR ex20ins, the mechanisms of acquired resistance to novel EGFR inhibitors, effective treatment that have good central nervous system penetrance, and the potential role of combination strategy.

EGFR exon 20 insertion variants A763_Y764insFQEA and D770delinsGY confer favorable sensitivity to currently approved EGFR-specific tyrosine kinase inhibitors

Background: The EGFR exon 20 insertions (ex20ins) D770_N771insSVD and V769_D770insASV are most frequent in non-small-cell lung cancer (NSCLC) and are associated with intrinsic resistance to currently approved EGFR tyrosine kinase inhibitors (TKIs). A763_Y764insFQEA and D770delinsGY, respectively, account for 3%-8% and 2.0%-4.8% of EGFR ex20ins in NSCLC and are associated with a more favorable response to EGFR-specific TKIs as per case reports. The aim of this study was to elucidate the molecular structures of these mutants and their binding affinities to diverse EGFR TKIs and compare the clinical outcomes in NSCLC patients harboring these mutations. Methods: A real-world cohort study was conducted to evaluate and compare the clinical outcomes of EGFR TKIs among NSCLC patients with different EGFR ex20ins mutants in response to EGFR TKIs. The structures of A763_Y764insFQEA and D770delinsGY were also analyzed and drug binding simulations were performed. Results: With a median follow-up of 24.0 months, the first-line objective response rate (ORR), disease control rate (DCR), and median progression-free survival (PFS) were, respectively, 0 (0/16), 50.0% (8/16), and 2.07 months (95%CI, 0-6.25) in patients harboring D770_N771insSVD and V769_D770insASV variants and 33.3% (4/12), 83.3% (10/12), and 9.97 months (95%CI, 4.75-15.19) in patients with A763_Y764insFQEA and D770delinsGY variants. There was a significant difference between the PFS of these two subgroups (median, 9.97 vs.2.07 months, HR = 0.33, 95%CI, 0.13-0.85, p = 0.02). Similarly, the PFS was significantly longer after second-line treatment with EGFR TKIs in patients harboring A763_Y764insFQEA and D770delinsGY compared to those with other insertions (median, 6.77 vs.2.23 months, HR = 0.14, p < 0.001). Computational simulations indicated that A763_Y764insFQEA and D770delinsGY mutants were structurally similar to wild-type EGFR. In contrast, the C-helix and phosphate-binding loop of D770_N771insSVD and V769_D770insASV had shifted into the drug-binding pocket, resulting in significant steric hindrance and a lack of affinity for the currently approved EGFR inhibitors. Conclusion: NSCLC patients harboring A763_Y764insFQEA and D770delinsGY insertions of EGFR are responsive to the currently approved EGFR TKIs as opposed to patients with the D770_N771insSVD and V769_D770insASV variants. Therefore, A763_Y764insFQEA and D770delinsGY should be classified as active mutations among heterogeneous EGFR ex20ins subtypes and the carriers can be treated with the suitable EGFR TKIs.

Non-small Cell Lung Cancer with EGFR or HER2 Exon 20 Insertion Mutations: Diagnosis and Treatment Options

Molecular testing is performed upon diagnosis of non-small cell lung cancer (NSCLC) because of the large success of targeted therapies for oncogenic mutations. Epidermal growth factor receptor (EGFR) mutations are the most commonly identified mutation in NSCLC, and EGFR exon 20 insertion mutations (exon20ins) are the third most common mutation in EGFR following EGFR exon 19 deletions and exon 21 L858R mutations. EGFR exon20ins have regularly demonstrated resistance to classical EGFR inhibition. Two treatments-mobocertinib and amivantamab-have recently been the first drugs to be approved by the US Food and Drug Administration (FDA) for treatment of lung cancers with these mutations following platinum-based therapy. Research surrounding these two drugs demonstrates strong efficacy, but with an intense array of side effects. Another targetable driver mutation is the human epidermal growth factor receptor 2 (HER2) exon20ins, representing approximately 2-3% of NSCLC patients. This mutation has been heavily studied in vitro as well as clinically, and trastuzumab deruxtecan was just recently granted accelerated FDA approval based on the high efficacy demonstrated in the Destiny-Lung01 study. However, similar to their EGFR counterparts, HER2 inhibitors also have evidence of toxicity in clinical studies. In this paper, we discuss the limited response of EGFR and HER2 exon20ins to a wide range of standard treatment regimens, such as platinum-based chemotherapy and classic EGFR tyrosine kinase inhibitors, as well as immunotherapy. We also review recently approved and upcoming targeted therapeutic options, considering what research is presently being done regarding efficacy and the reduction of side effects, as well as the agents' risks and benefits for incorporation into an approved treatment regimen.

Discovery of mobocertinib, a new irreversible tyrosine kinase inhibitor indicated for the treatment of non-small-cell lung cancer harboring EGFR exon 20 insertion mutations

Epidermal growth factor receptor (EGFR) is essential for normal cellular functions. Mutations of EGFR’s kinase domain can cause dysregulation leading to non-small cell lung cancer (NSCLC). Exon 20 insertion (ex20ins) mutations in EGFR are one of the leading contributors to oncogenesis and confer insensitivity to most available therapeutics. Mobocertinib is a novel tyrosine kinase inhibitor (TKI) recently approved by the US FDA as a first-in-class small molecule therapeutic for EGFR ex20ins-positive NSCLC. When compared to osimertinib, a TKI indicated for the treatment of EGFR T790M-positive NSCLC, mobocertinib differs only by the presence of an additional C5-carboxylate isopropyl ester group on the middle pyrimidine core. Together with the acrylamide side chain that is responsible for irreversible inhibition, this additional C5-substituent affords mobocertinib high anticancer potency and specificity to EGFR ex20ins-positive lung cancer that is resistant to other EGFR TKIs. This review article provides an overview of the discovery of mobocertinib from osimertinib including their structure-activity relationships, mechanisms of action, preclinical pharmacology, pharmacokinetics, and clinical applications. The discovery and use of mobocertinib and other EGFR TKIs demonstrate the power of structure-based drug design and promising therapeutic outcomes of using precision medicine approaches in the management of molecularly defined tumors.

Case Report: A good response to furmonertinib second-line treatment of an advanced lung adenocarcinoma patient with a rare EGFR exon 20 N771_P772insH mutation: A case report and literature review

Background: Lung adenocarcinoma with the classical EGFR 19 deletion and exon 21 L858R point mutations has exhibited good responses to epidermal growth factor receptor tyrosine kinase inhibitors (EGFR-TKIs) treatment. However, the sensitivity of uncommon EGFR exon 20 insertion mutation to third-generation EGFR-TKIs has not been determined. Although emerging targeted therapies for EGFR exon 20 insertion mutation have been reported in recent years, such patients still have a poorer prognosis than those with typical or wild-type EGFR mutations.

Case summary: Here, we report the case of a 57-year-old man with advanced non-small cell lung cancer (NSCLC) with a rare EGFR exon 20 N771_P772insH mutation. The patient was treated with furmonertinib as second-line therapy. Although his pleural effusion was more than before that during treatment, various examination results showed that the pleural effusion was closely related to hypoproteinemia; thus, local progression was not considered. His cough was significantly alleviated, and the dose was well tolerated. The patient was evaluated for a remarkable progression-free survival (PFS) of 10.0 months, a duration of response (DOR) of 8.0 months, and an overall survival (OS) of 22.0 months, which had not previously been achieved.

Conclusion: The present study indicated that furmonertinib might be a good treatment option for first-line progressive NSCLC patients with EGFR exon 20 insertion mutation.

Clinical Validation of Companion Diagnostics for the Selection of Patients with Non-Small Cell Lung Cancer Tumors Harboring Epidermal Growth Factor Receptor Exon 20 Insertion Mutations for Treatment with Amivantamab

Amivantamab, an epidermal growth factor receptor (EGFR)-c-Met bispecific antibody, targets activating/resistance EGFR mutations and MET mutations/amplifications. In the ongoing CHRYSALIS study (ClinicalTrials.gov identifier NCT02609776), amivantamab demonstrated antitumor activity in patients with non-small cell lung cancer harboring EGFR exon 20 insertion mutations (ex20ins) that progressed on or after platinum-based chemotherapy, a population in which amivantamab use has been approved by the US Food and Drug Administration. This bridging study clinically validated two novel candidate companion diagnostics (CDx) tools for use in detecting EGFR ex20ins in plasma and tumor tissue, Guardant360 CDx and Oncomine Dx Target Test (ODxT), respectively. From the 81 patients in the CHRYSALIS efficacy population, 78 plasma and 51 tissue samples were tested. Guardant360 identified 62 positive (16 negative), and ODxT identified 39 positive (3 negative), samples with EGFR ex20ins. Baseline demographic and clinical characteristics were similar between the CHRYSALIS, Guardant360, and ODxT-identified populations. Agreement with local PCR/next-generation sequencing tests used for enrollment into CHRYSALIS demonstrated high adjusted negative (99.6% and 99.9%) and positive (100% for both) predictive values with the Guardant360 CDx and ODxT tests, respectively. Overall response rates were comparable between the CHRYSALIS, Guardant360 CDx, and ODxT populations. Both the plasma- and tissue-based diagnostic tests provided accurate, comprehensive, and complementary approaches to identifying patients with EGFR ex20ins who could benefit from amivantamab therapy.

Allele-specific activation, enzyme kinetics, and inhibitor sensitivities of EGFR exon 19 deletion mutations in lung cancer

Epidermal growth factor receptor (EGFR) mutations are detected in approximately 30% of all lung adenocarcinomas, and the most common EGFR mutation occurring in ∼50% of patients is termed “exon 19 deletion” (ex19del). Despite the existence of dozens of different genomic variants comprising what is generically referred to clinically as ex19del, clinicians currently do not distinguish between ex19del variants in considering treatment options, and differences between ex19del variants are largely unstudied in the broader scientific community. Herein, we describe functional differences between distinct EGFR ex19del variants attributable to the structural features of each variant. These findings suggest a possible explanation for observed differences in patient outcomes stratified by ex19del subtype and reinforce the need for allele-specific considerations in clinical treatment decision-making.

Oncogenic mutations within the epidermal growth factor receptor (EGFR) are found in 15 to 30% of all non–small-cell lung carcinomas. The term exon 19 deletion (ex19del) is collectively used to refer to more than 20 distinct genomic alterations within exon 19 that comprise the most common EGFR mutation subtype in lung cancer. Despite this heterogeneity, clinical treatment decisions are made irrespective of which EGFR ex19del variant is present within the tumor, and there is a paucity of information regarding how individual ex19del variants influence protein structure and function. Herein, we identified allele-specific functional differences among ex19del variants attributable to recurring sequence and structure motifs. We built all-atom structural models of 60 ex19del variants identified in patients and combined molecular dynamics simulations with biochemical and biophysical experiments to analyze three ex19del mutations (E746_A750, E746_S752 > V, and L747_A750 > P). We demonstrate that sequence variation in ex19del alters oncogenic cell growth, dimerization propensity, enzyme kinetics, and tyrosine kinase inhibitor (TKI) sensitivity. We show that in contrast to E746_A750 and E746_S752 > V, the L747_A750 > P variant forms highly active ligand-independent dimers. Enzyme kinetic analysis and TKI inhibition experiments suggest that E746_S752 > V and L747_A750 > P display reduced TKI sensitivity due to decreased adenosine 5′-triphosphate K_m. Through these analyses, we propose an expanded framework for interpreting ex19del variants and considerations for therapeutic intervention.

Optimizing diagnosis and treatment of EGFR exon 20 insertions mutant NSCLC

The Epidermal growth factor receptor (EGFR) exon (ex) 20 insertions (ins) has been considered as an "undruggable target" for a long time, with platinum-pemetrexed combination recommended as upfront standard treatment for newly diagnosed advanced non-small cell lung cancer (NSCLC) patients. Recent preliminary data from early phase clinical trials have demonstrated that pharmacological inhibition of EGFRex20ins is possible, offering new treatment opportunities to 1-2% of advanced NSCLC patients harboring such hard-to-treat molecular alteration. Among the different drugs under clinical investigation, both amivantamab and mobocertinib have received regulatory approval in the United States, by the Food and Drugs Administration (FDA), while amivantamab has been recently approved also in Europe, for the clinical treatment of advanced NSCLC patients harboring EGFRex20ins who failed at least one prior line of systemic therapy, representing a major breakthrough in lung cancer treatment over the last year. With novel effective targeted options on the horizon, there is a renewed interest on optimizing the molecular screening of advanced NSCLC, and next-generation sequencing (NGS)-based genotyping is currently considered the gold standard approach to profile advanced NSCLC patients, as recommended by international guidelines. Herein we provide an updated overview of the most recent findings and upcoming challenges regarding both molecular detection and therapeutic management of EGFR ex20ins mutant advanced NSCLC patients.

Poziotinib for EGFR exon 20-mutant NSCLC: Clinical efficacy, resistance mechanisms, and impact of insertion location on drug sensitivity

We report a phase II study of 50 advanced non-small cell lung cancer (NSCLC) patients with point mutations or insertions in EGFR exon 20 treated with poziotinib (NCT03066206). The study achieved its primary endpoint, with confirmed objective response rates (ORRs) of 32% and 31% by investigator and blinded independent review, respectively, with a median progression-free survival of 5.5 months. Using preclinical studies, in silico modeling, and molecular dynamics simulations, we found that poziotinib sensitivity was highly dependent on the insertion location, with near-loop insertions (amino acids A767 to P772) being more sensitive than far-loop insertions, an observation confirmed clinically with ORRs of 46% and 0% observed in near versus far-loop, respectively (p = 0.0015). Putative mechanisms of acquired resistance included EGFR T790M, MET amplifications, and epithelial-to-mesenchymal transition (EMT). Our data demonstrate that poziotinib is active in EGFR exon 20-mutant NSCLC, although this activity is influenced by insertion location.

First-line immunotherapy or angiogenesis inhibitor combined with chemotherapy for advanced non-small cell lung cancer with EGFR exon 20 insertions: Real-world evidence from China

BACKGROUND

Currently, survival benefit of immunotherapy in advanced non-small cell lung cancer (NSCLC) with EGFR exon 20 insertions (ex20ins) is controversial, though it generally indicates poor response and activity. Compared with standard chemotherapy in combination with bevacizumab, first-line chemotherapy plus immune checkpoint inhibitor (ICI) in advanced NSCLC with EGFR ex20ins remains elusive and lacks real-world evidence.

PATIENTS AND METHODS

A retrospective real-world study was conducted to evaluate clinical outcomes of chemotherapy alone (C), chemotherapy plus ICI (C + I), or chemotherapy plus angiogenesis inhibitors (C + A) as first-line strategies for advanced NSCLC patients with EGFR ex20ins. Investigator-assessed response and survival outcomes were compared between subgroups. Kyoto Encyclopedia of Genes and Genomes (KEGG) analysis was conducted to reveal concomitant alterations and explore the molecular landscape of ex20ins.

RESULTS

A total of 164 patients were screened, identifying 35 kinds of ex20ins, and 122 cases treated with C, C + I, and C + A were finally included in the first-line analysis. C + A achieved much better objective response rate (ORR, 38.1% vs. 18.2%) and significant progression-free survival (PFS) benefit compared with C (median, 7.73 vs.5.93 months, HR = 0.60, 95% CI: 0.40-0.90, p = 0.014), and it showed similar ORR (38.1% vs. 40.0%), but higher disease control rate (DCR, 96.8% vs. 80.0%) and numerically longer median PFS (7.73 vs. 6.53 months, HR = 0.83, 95% CI: 0.44-1.56, p = 0.30) than C + I. There was no PFS difference between C + I and C, despite of PD-L1 expression or tumor mutational burden. KEGG analysis revealed concomitant upregulation of PI3K/AKT signaling might mediate intrinsic resistance to ICI in ex20ins.

CONCLUSION

First-line chemotherapy plus angiogenesis inhibitors might yield more survival benefits than chemotherapy alone for NSCLC with EGFR ex20ins, whereas, it suggests that chemotherapy in combination with ICI might not obtain a better survival benefit for this subset of patients. Activation of PI3K/AKT signaling might mediate intrinsic immunosuppression in NSCLC with EGFR ex20ins.

Treatment Strategies for Non-Small Cell Lung Cancer Harboring Common and Uncommon EGFR Mutations: Drug Sensitivity Based on Exon Classification, and Structure-Function Analysis

Simple Summary

The advent of epidermal growth factor receptor (EGFR) tyrosine kinase inhibitors (EGFR-TKIs) has led to a dramatic improvement in the prognosis of patients having advanced EGFR-mutant non-small cell lung cancer (NSCLC). NSCLCs harboring “common” EGFR mutations, including exon 19 deletions and exon 21 L858R mutation substitutions, are sensitive to EGFR-TKIs. However, NSCLCs harboring “uncommon” EGFR mutations have poor sensitivity to EGFR-TKIs, and patients harboring uncommon mutations often experience poor outcomes. Here, we review the current EGFR-TKI therapy and the development of treatment strategies, including combined treatment and the exploration of new drugs. In addition, we discuss EGFR-TKI sensitivity based on structure-function analysis.

Abstract

The identification of epidermal growth factor receptor (EGFR) mutations and development of EGFR tyrosine kinase inhibitors (EGFR-TKIs) have dramatically improved the prognosis of advanced EGFR-mutated non-small cell lung cancer (NSCLC), setting a landmark in precision oncology. Exon 19 deletions and exon 21 L858R substitutions, which comprise the majority of common EGFR mutations, are predictors of good sensitivity to EGFR-TKIs. However, not all cancers harboring EGFR mutations are sensitive to EGFR-TKIs. Most patients harboring uncommon EGFR mutations demonstrate a poorer clinical response than those harboring common EGFR mutations. For example, cancers harboring exon 20 insertions, which represent approximately 4–12% of EGFR mutations, are generally insensitive to first- and second-generation EGFR-TKIs. Although understanding the biology of uncommon EGFR mutations is essential for developing treatment strategies, there is little clinical data because of their rarity. Moreover, clarifying the acquired resistance of EGFR-mutated NSCLC may lead to more precise treatments. Sequencing and structure-based analyses of EGFRmutated NSCLC have revealed resistance mechanisms and drug sensitivity. In this review, we discuss the strategies in development for treating NSCLC harboring common and uncommon EGFR mutations. We will also focus on EGFR-TKI sensitivity in patients harboring EGFR mutations based on the structural features.

Non-Small Cell Lung Cancer, Version 3.2022, NCCN Clinical Practice Guidelines in Oncology

NCCN Clinical Practice Guidelines in Oncology (NCCN Guidelines) for Non-Small Cell Lung Cancer (NSCLC) provide recommended management for patients with NSCLC, including diagnosis, primary treatment, surveillance for relapse, and subsequent treatment. Patients with metastatic lung cancer who are eligible for targeted therapies or immunotherapies are now surviving longer. This selection from the NCCN Guidelines for NSCLC focuses on targeted therapies for patients with metastatic NSCLC and actionable mutations.

Targeting Acquired and Intrinsic Resistance Mechanisms in Epidermal Growth Factor Receptor Mutant Non-Small-Cell Lung Cancer

Over the past 2 decades, rapid advances in molecular profiling and the development of targeted therapies have dramatically improved the clinical course of advanced non-small-cell lung cancer (NSCLC). Mutations in the epidermal growth factor receptor (EGFR) gene are found in about a third of patients with advanced NSCLC, and the approval of first-generation EGFR targeted kinase inhibitors significantly improved survival when compared with platinum-based doublet chemotherapy (PBC), the previous standard of care. Inevitably, selective pressure from first-generation EGFR inhibitors led to acquired resistance mechanisms, such as the T790M mutation. The advent of third-generation EGFR inhibitors (e.g., osimertinib) successfully overcame the T790M resistance mechanism, and osimertinib subsequently became the first-line therapy for EGFR mutant NSCLC. Currently, research in EGFR mutant NSCLC is primarily focused on targeting resistance mechanisms to osimertinib. Over the past several years, many important acquired and intrinsic mechanisms of resistance to osimertinib have been identified. Acquired resistance mechanisms include C797X, mesenchymal epithelial transition factor (MET) amplification, HER2/HER3 amplification, phosphoinositide 3-kinase (PI3K) pathway mutations, RAS/mitogen-activated protein kinase (MAPK) pathway mutations, cell-cycle gene alterations, oncogenic fusions, and histologic transformations. An important intrinsic resistance mechanism to osimertinib is the EGFR exon 20 insertion mutation, which is sensitive to the newly Food and Drug Administration (FDA)-approved tyrosine kinase inhibitor mobocertinib and the EGFR/MET bispecific antibody amivantamab. This review article aims to (1) summarize the advances in the treatment of EGFR mutant NSCLC, (2) delineate known resistance mechanisms to the current first-line therapy, osimertinib, and (3) describe the development of targeted drugs that aim to overcome these resistance mechanisms.

Sunvozertinib, a selective EGFR inhibitor for previously treated non-small cell lung cancer with EGFR exon 20 insertion mutations

Epidermal growth factor receptor exon 20 insertion mutations (EGFR exon20ins) are detected in approximately 2% of patients with non-small cell lung cancer (NSCLC). Due to lack of effective therapy, the prognosis of these patients was poor. Sunvozertinib (DZD9008) was designed as an oral, potent, irreversible and selective EGFR tyrosine kinase inhibitor, showing activity against EGFR exon20ins and other mutations. In both cell lines and xenograft models, sunvozertinib shows potent antitumor activity. In the two ongoing phase 1 clinical studies, sunvozertinib was tolerated up to 400 mg once daily. The most common drug-related adverse events included diarrhea and skin rash. Antitumor efficacy was observed at the doses of 100 mg and above in patients with EGFR exon20ins NSCLC across different subtypes, with prior amivantamab treatment as well as with baseline brain metastasis. The median duration of response (DoR) has not been reached.

Pediatric High Grade Glioma Classification Criteria and Molecular Features of a Case Series

Pediatric high-grade gliomas (pHGGs) encompass a heterogeneous group of tumors. Three main molecular types (H3.3 mutant, IDH mutant, and H3.3/IDH wild-type) and a number of subtypes have been identified. We provide an overview of pHGGs and present a mono-institutional series. We studied eleven non-related pHGG samples through a combined approach of routine diagnostic tools and a gene panel. TP53 and H3F3A were the most mutated genes (six patients each, 54%). The third most mutated gene was EGFR (three patients, 27%), followed by PDGFRA and PTEN (two patients each, 18%). Variants in the EZHIP, MSH2, IDH1, IDH2, TERT, HRAS, NF1, BRAF, ATRX, and PIK3CA genes were relatively infrequent (one patient each, 9%). In one case, gene panel analysis documented the presence of a pathogenic IDH2 variant (c.419G>A, p.Arg140Gln) never described in gliomas. More than one-third of patients carry a variant in a gene associated with tumor-predisposing syndromes. The absence of constitutional DNA did not allow us to identify their constitutional origin.

EGFR exon 20 Insertion NSCLC and Response to Platinum-Based Chemotherapy

INTRODUCTION

In classical EGFR mutant non-small-cell lung cancer (NSCLC), EGFR tyrosine kinase inhibitor (TKI) therapy yields better outcomes than platinum-based chemotherapy. However, EGFR exon 20 insertion (ex20ins) NSCLC is relatively resistant to currently available EGFR TKIs. Though platinum-based chemotherapy is the frontline standard of care for EGFR ex20ins NSCLC, its efficacy is not fully described.

STUDY DESIGN

A retrospective, single-center, case series METHODS: Patients were identified through an electronic research database at a single institution and included if they had advanced EGFR ex20ins NSCLC, received platinum-based chemotherapy for metastatic disease, and had scans evaluable for response. Each patient's demographics, tumor characteristics, and clinical course were recorded. Treatment response was evaluated using RECIST v1.1 criteria, and the PFS was calculated by the Kaplan-Meier method.

RESULTS

Among 27 patients identified with EGFR ex20ins NSCLC at our institution, 18 (67%) received platinum-based chemotherapy for metastatic disease and had scans evaluable for response. These patients received platinum-based chemotherapy in the first-line (N = 17, 94%) and second-line settings (N = 1, 6%). The objective response rate (ORR) to platinum-based chemotherapy was 39% (7 of 18 patients; 95% confidence interval [CI] 16-61). The median PFS with platinum-based chemotherapy was 7.1 months (95% CI, 6.3 -13.7), and the median overall survival was 3.2 years (95% CI, 1.92 - NR).

CONCLUSIONS

The efficacy of platinum-based chemotherapy in EGFR ex20ins NSCLC is similar to that expected for TKI sensitive EGFR mutant NSCLC. Novel agents designed to specifically target ex20ins mutant EGFR should additionally improve outcomes.

Case Report: Partial Response Following Nivolumab Plus Docetaxel in a Patient With EGFR Exon 20 Deletion/Insertion (p.N771delinsGF) Mutant Lung Adenocarcinoma Transdifferentiated From Squamous Cell Carcinoma

The histological transformation from lung squamous cell carcinoma (LUSC) to lung adenocarcinoma (LUAD) and p. N771delinsGF mutations in EGFR exon 20 (ex20) are exceedingly rare in non–small cell lung carcinoma (NSCLC). EGFR ex20 mutations are insensitive to EGFR tyrosine kinase inhibitors in NSCLC. Here, we present a 76-year-old male smoker harboring LUAD with a novel p. N771delinsGF deletion/insertion mutation in EGFR ex20 transdifferentiating from advanced LUSC after chemoradiotherapy. The patient presented reduced hydrothorax and relieved tightness with the treatment of nivolumab plus docetaxel and carboplatin after the failure of second-line chemotherapy. The case highlights the importance of rebiopsy and molecular retesting after the progression of lung cancer and supports the idea that the combination of immune checkpoint blockade and chemotherapy may be an attractive option for patients with EGFR ex20 mutations associated with LUSC–LUAD transformation.

Structural Insight and Development of EGFR Tyrosine Kinase Inhibitors

Lung cancer has a high prevalence, with a growing number of new cases and mortality every year. Furthermore, the survival rate of patients with non-small-cell lung carcinoma (NSCLC) is still quite low in the majority of cases. Despite the use of conventional therapy such as tyrosine kinase inhibitor for Epidermal Growth Factor Receptor (EGFR), which is highly expressed in most NSCLC cases, there was still no substantial improvement in patient survival. This is due to the drug’s ineffectiveness and high rate of resistance among individuals with mutant EGFR. Therefore, the development of new inhibitors is urgently needed. Understanding the EGFR structure, including its kinase domain and other parts of the protein, and its activation mechanism can accelerate the discovery of novel compounds targeting this protein. This study described the structure of the extracellular, transmembrane, and intracellular domains of EGFR. This was carried out along with identifying the binding pose of commercially available inhibitors in the ATP-binding and allosteric sites, thereby clarifying the research gaps that can be filled. The binding mechanism of inhibitors that have been used clinically was also explained, thereby aiding the structure-based development of new drugs.

EGFR Exon 20 Insertion Mutations in Sinonasal Squamous Cell Carcinoma

Recurrent epidermal growth factor receptor (EGFR)-activating mutations have been identified in a rare form of head and neck cancer known as sinonasal squamous cell carcinoma (SNSCC), a malignant disease with a 5-year mortality rate of ~40%. Interestingly, the majority of EGFR mutations identified in patients with primary SNSCC are exon 20 insertions (Ex20ins), which is in contrast to non-small-cell lung cancer (NSCLC), where the EGFR exon 19 deletion and L858R mutations predominate. These studies demonstrate that EGFR Ex20ins mutations are not exclusive to lung cancer as previously believed, but are also involved in driving SNSCC pathogenesis. Here we review the landscape of EGFR mutations in SNSCC, with a particular focus on SNSCC associated with inverted sinonasal papilloma (ISP), a benign epithelial neoplasm. Taking lessons from NSCLC, we also discuss potential new treatment options for ISP-associated SNSCC harbouring EGFR Ex20ins in the context of targeted therapies, drug resistance and precision cancer medicine. Moving forward, further basic and translational work is needed to delineate the biology of EGFR Ex20ins in SNSCC in order to develop more effective treatments for patients with this rare disease.

Amivantamab for the treatment of EGFR exon 20 insertion mutant non-small cell lung cancer

INTRODUCTION

Amivantamab is a monoclonal bispecific anti-EGFR-MET antibody that is the first targeted therapy to be approved for non-small cell lung cancer (NSCLC) patients harboring EGFR exon 20 insertion mutations following progression on chemotherapy, marking a watershed moment for a class of mutations which is generally associated with poor outcomes.

AREAS COVERED

In this article, we outline the drug profile of amivantamab compared with EGFR kinase inhibitors under evaluation in EGFR exon 20 insertion mutant NSCLC. We also review the efficacy and safety data reported from the CHRYSALIS phase I trial, which forms the basis of the recent approval of amivantamab.

EXPERT OPINION

Unlike small molecule EGFR kinase inhibitors, amivantamab has an extracellular mode of action and dual activity against EGFR and MET. It remains to be determined what role MET inhibition plays in toxicity and efficacy and whether dual target inhibition can delay the onset of drug resistance in these cancers. Due to its large molecular size, amivantamab is expected to have poor activity to treat brain metastases. Building on the clinical data so far, future trials that will evaluate combination treatments with brain-penetrant EGFR kinase inhibitors will be critical to move the drug toward a first-line treatment.

EGFR-D770>GY and Other Rare EGFR Exon 20 Insertion Mutations with a G770 Equivalence Are Sensitive to Dacomitinib or Afatinib and Responsive to EGFR Exon 20 Insertion Mutant-Active Inhibitors in Preclinical Models and Clinical Scenarios

Epidermal growth factor receptor (EGFR) exon 20 insertion mutations account for a tenth of all EGFR mutations in lung cancers. An important unmet clinical need is the identification of EGFR exon 20 insertion mutants that can respond to multiple classes of approved EGFR-TKIs. We sought to characterize variants involving EGFR-D770 to EGFR-G770 position equivalence changes that structurally allow for response to irreversible 2nd generation EGFR-TKIs. Our group used preclinical models of EGFR exon 20 insertion mutations to probe representative 1st (erlotinib), 2nd (afatinib, dacomitinib), 3rd generation (osimertinib) and EGFR exon 20 insertion mutant-active (poziotinib, mobocertinib) TKIs; we also queried the available clinical literature plus our institutional database to enumerate clinical outcomes. EGFR-D770>GY and other EGFR insertions with a G770 equivalence were identified at a frequency of 3.96% in separate cohorts of EGFR exon 20 insertion mutated lung cancer (n = 429). Cells driven by EGFR-D770>GY were insensitive to erlotinib and osimertinib, displayed sensitivity to poziotinib and dacomitinib and were uniquely sensitive to afatinib and dacomitinib in comparison with other more typical EGFR exon 20 insertion mutations using proliferation and biochemical assays. Clinical cases with EGFR-G770 equivalence from the literature and our center mirrored the preclinical data, with radiographic responses and clinical benefits restricted to afatinib, dacomitinib, poziotinib and mobocertinib, but not to erlotinib or osimertinib. Although they are rare, at <4% of all exon 20 insertion mutations, EGFR-G770 equivalence exon 20 insertion mutations are sensitive to approved 2nd generation EGFR TKIs and EGFR exon 20 insertion mutant-active TKIs (mobocertinib and poziotinib). EGFR-D770>GY and other insertions with a G770 equivalence join EGFR-A763_Y764insFQEA as exon 20 insertion mutationsresponsive to approved EGFR TKIs beyond mobocertinib; this data should be considered for clinical care, genomic profiling reports and clinical trial elaboration.

Uncommon EGFR mutations in non-small-cell lung cancer: A systematic literature review of prevalence and clinical outcomes

Mutations in exons 18-21 of the epidermal growth factor receptor gene (EGFR) can confer sensitivity to EGFR-tyrosine kinase inhibitors (EGFR-TKIs) in patients with non-small-cell lung cancer (NSCLC). Deletions in exon 19 or the exon 21 L858R substitution comprise approximately 85% of mutations, but comparatively few data are available on the remaining "uncommon" mutations. We conducted a systematic literature review to identify evidence on uncommon EGFR mutations in locally advanced/metastatic NSCLC (PROSPERO registration number: CRD42019126583). Electronic screening and congress searches identified studies published in 2012-2020 including patients with locally advanced/metastatic NSCLC and uncommon EGFR mutations (excluding T790M). We assessed the prevalence of uncommon mutations (in studies using direct sequencing of exons 18-21), and compared response to treatment and progression-free survival (PFS) in patients with common versus uncommon mutations and in those with exon 20 mutations versus other uncommon mutations. We identified 64 relevant studies. Uncommon mutations constituted 1.0-18.2% of all EGFR mutations, across 10 studies. The most frequently reported uncommon mutations were G719X (0.9-4.8% of all EGFR mutations), exon 20 insertions (Ex20ins; 0.8-4.2%), L861X (0.5-3.5%), and S768I (0.5-2.5%). Patients with common mutations typically experienced better treatment response and longer PFS on EGFR-TKIs than patients with uncommon mutations; Ex20ins mutations were associated with less favourable outcomes than other uncommon mutations. This review shows that uncommon mutations may comprise a clinically significant proportion of the EGFR mutations occurring in NSCLC, and highlights disparities in EGFR-TKI sensitivity between different uncommon mutations.

Hitting the Right Spot: Advances in the Treatment of NSCLC With Uncommon EGFR Mutations

An understanding of the biology of uncommon epidermal growth factor receptor (EGFR) mutations in non-small cell lung cancer (NSCLC) is evolving. These mutations are important for the selection of targeted therapy and the development of resistance. The advent of genomic profiling has led to guideline-recommended molecular testing to identify patients with NSCLC who carry uncommon EGFR mutations to aid in the selection of appropriate targeted therapy. This article discusses the efficacy and safety of current and emerging targeted therapies for the treatment of uncommon EGFR mutations in NSCLC to aid in developing patient-specific treatment plans.