Clinical and molecular characteristics of non-small-cell lung cancer (NSCLC) harboring EGFR mutation: results of the nationwide French Cooperative Thoracic Intergroup (IFCT) program

Activity of osimeRTInib in non-small-cell lung Cancer with UNcommon epidermal growth factor receptor mutations: retrospective Observational multicenter study (ARTICUNO)

BACKGROUND

Osimertinib represents the standard of care for the treatment of advanced non-small-cell lung cancer (NSCLC) harboring classical epidermal growth factor receptor (EGFR) mutations, constituting 80%-90% of all EGFR alterations. In the remaining cases, an assorted group of uncommon alterations of EGFR (uEGFR) can be detected, which confer variable sensitivity to previous generations of EGFR inhibitors, overall with lower therapeutic activity. Data on osimertinib in this setting are limited and strongly warranted.

PATIENTS AND METHODS

The ARTICUNO study retrospectively evaluated data on osimertinib activity from patients with advanced NSCLC harboring uEGFR treated in 21 clinical centers between August 2017 and March 2023. Data analysis was carried out with a descriptive aim. Investigators collected response data according to RECIST version 1.1 criteria. The median duration of response, progression-free survival (mPFS), and overall survival were estimated by the Kaplan-Meier method.

RESULTS

Eighty-six patients harboring uEGFR and treated with osimertinib were identified. Patients with 'major' uEGFR, that is, G719X, L861X, and S768I mutations (n = 51), had an overall response rate (ORR) and mPFS of 50% and 9 months, respectively. Variable outcomes were registered in cases with rarer 'minor' mutations (n = 27), with ORR and mPFS of 31% and 4 months, respectively. Among seven patients with exon 20 insertions, ORR was 14%, while the best outcome was registered among patients with compound mutations including at least one classical EGFR mutation (n = 13). Thirty patients presented brain metastases (BMs) and intracranial ORR and mPFS were 58% and 9 months, respectively. Amplification of EGFR or MET, TP53 mutations, and EGFR E709K emerged after osimertinib failure in a dataset of 18 patients with available rebiopsy.

CONCLUSION

The ARTICUNO study confirms the activity of osimertinib in patients with uEGFR, especially in those with compound uncommon-common mutations, or major uEGFR, even in the presence of BMs. Alterations at the E709 residue of EGFR are associated with resistance to osimertinib.

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.

Efficacy and safety of dacomitinib in treatment-naïve patients with advanced NSCLC harboring uncommon EGFR mutation: an ambispective cohort study

BACKGROUND

About 10% of non-small cell lung cancer (NSCLC) patients with epidermal growth factor receptor (EGFR) mutations are harbored as uncommon mutations. This study aimed to explore the efficacy and safety of dacomitinib, a second-generation EGFR tyrosine kinase inhibitor (EGFR-TKIs), in treating uncommon EGFR-mutated advanced NSCLC.

METHODS

Treatment-naïve advanced NSCLC patients treated with dacomitinib at Hunan Cancer Hospital with uncommon EGFR mutations were evaluated. The primary endpoint was progression-free survival (PFS). Secondary end points included overall survival (OS), objective response rate (ORR), disease control rate (DCR) and safety.

RESULT

Between December 2019 and December 2021, a total of 16 patients was included. Median PFS was 14.0 (95% CI 4.32-23.7) months, and median OS was not reached. ORR was 68.8% (95% CI 41.3 to 89.0%) and DCR was 93.8% (95%CI 69.8 to 99.8%), including three achieving complete remission (CR) and eight achieving partial remission (PR). Median PFS for patients with brain metastasis was 9.0 (95%CI 6.9 to 11.1) months. Intracranial ORR was 100%, including 2 CR and 4 PR. Major treatment-related adverse events (TRAEs) included rash (87.5%), paronychia (62.5%), oral ulcers (50.0%), and diarrhea (50.0%), none of which were ≥ grade 3 TRAEs.

CONCLUSIONS

Dacomitinib showed good activity and manageable toxicity in NSCLC patients with uncommon EGFR mutations.

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.

EGFR-mutated non-small lung cancer brain metastases and radiosurgery outcomes with a focus on leptomeningeal disease

PURPOSE

Patients with EGFR-mutated NSCLC represent a unique subset of lung cancer patients with distinct clinical and molecular characteristics. Previous studies have shown a higher incidence of brain metastases (BM) in this subgroup of patients, and neurologic death has been reported to be as high as 40% and correlates with leptomeningeal disease (LMD).

METHODS

Between 2012 and 2021, a retrospective review of our prospective registry identified 606 patients with BM from NSCLC, with 170 patients having an EGFR mutation. Demographic, clinical, radiographic, and treatment characteristics were correlated to the incidence of LMD and survival.

RESULTS

LMD was identified in 22.3% of patients (n = 38) at a median follow-up of 19 (2-98) months from initial SRS. Multivariate regression analysis showed targeted therapy and a cumulative number of metastases as significant predictors of LMD (p = 0.034, HR = 0.44), (p = .04, HR = 1.02). The median survival time after SRS of the 170 patients was 24 months (CI 95% 19.1-28.1). In a multivariate Cox regression analysis, RPA, exon 19 deletion, and osimertinib treatment were significant predictors of overall survival. The cumulative incidence of neurological death at 2 and 4 years post initial stereotactic radiosurgery (SRS) was 8% and 11%, respectively, and correlated with LMD.

CONCLUSION

The study shows that current-generation targeted therapy for EGFR-mutated NSCLC patients may prevent the development and progression of LMD, leading to improved survival outcomes. Nevertheless, LMD is associated with poor outcomes and neurologic death, making innovative strategies to treat LMD essential.

Efficacy and safety of EGFR-TKIs in combination with angiogenesis inhibitors as first-line therapy for advanced EGFR-mutant non-small-cell lung cancer: a systematic review and meta-analysis

BACKGROUND

For patients with advanced non-small-cell lung cancer (NSCLC) with EGFR mutations, the suggested course of action is epidermal growth factor receptor-tyrosine kinase inhibitors (EGFR-TKIs). Even with a high disease control rate, a majority of patients develop acquired EGFR-TKIs resistance and eventually advance. To increase the benefits of treatment, clinical trials are increasingly exploring the value of EGFR-TKIs combined with angiogenesis inhibitors as a first-line treatment in advanced NSCLC carrying EGFR mutations.

METHOD

Using PubMed, EMBASE and Cochrane Library, to locate published full-text articles in print or online, a thorough literature search was done from the database's inception to February 2021. Additionally, oral presentation RCTs from ESMO and ASCO were obtained. We sifted out RCTs that used EGFR-TKIs along with angiogenesis inhibitors as first-line therapy for advanced EGFR-mutant NSCLC. ORR, AEs, OS, and PFS were the endpoints. Review Manager version 5.4.1 was used for data analysis.

RESULTS

One thousand eight hundred twenty-one patients were involved in 9 RCTs. According to the results, combining EGFR-TKIs with angiogenesis inhibitors therapy prolonged PFS of advanced EGFR-mutation NSCLC patients on the whole [HR:0.65 (95%CI: 0.59~0.73, P<0.00001)]. No significant statistical difference was identified between the combination group and single drug group in OS(P=0.20) and ORR (P=0.11). There are more adverse effects when EGFR-TKIs are used in combination with angiogenesis inhibitors than when used alone.

CONCLUSION

The combination of EGFR-TKIs and angiogenesis inhibitors prolonged PFS in patients with EGFR-mutant advanced NSCLC, but the OS and ORR benefit was not significant, and the risk of adverse events was higher, more pronounced with hypertension and proteinuria; PFS in subgroups suggested that the combination was associated with better PFS in the smoking, liver metastasis, and no brain metastasis groups, and the included studies suggested that the smoking group , liver metastasis group, and brain metastasis group may have a potential OS benefit.

The Resistance to EGFR-TKIs in Non-Small Cell Lung Cancer: From Molecular Mechanisms to Clinical Application of New Therapeutic Strategies

Almost 17% of Western patients affected by non-small cell lung cancer (NSCLC) have an activating epidermal growth factor receptor (EGFR) gene mutation. Del19 and L858R are the most-common ones; they are positive predictive factors for EGFR tyrosine kinase inhibitors (TKIs). Currently, osimertinib, a third-generation TKI, is the standard first-line therapy for advanced NSCLC patients with common EGFR mutations. This drug is also administered as a second-line treatment for those patients with the T790M EGFR mutation and previously treated with first- (erlotinib, gefitinib) or second- (afatinib) generation TKIs. However, despite the high clinical efficacy, the prognosis remains severe due to intrinsic or acquired resistance to EGRF-TKIs. Various mechanisms of resistance have been reported including the activation of other signalling pathways, the development of secondary mutations, the alteration of the downstream pathways, and phenotypic transformation. However, further data are needed to achieve the goal of overcoming resistance to EGFR-TKIs, hence the necessity of discovering novel genetic targets and developing new-generation drugs. This review aimed to deepen the knowledge of intrinsic and acquired molecular mechanisms of resistance to EGFR-TKIs and the development of new therapeutic strategies to overcome TKIs' resistance.

Overall survival in advanced epidermal growth factor receptor mutated non-small cell lung cancer using different tyrosine kinase inhibitors in The Netherlands: a retrospective, nationwide registry study

Background

Clinical guidelines advise osimertinib as preferred first line treatment for advanced epidermal growth factor receptor (EGFR) mutated non-small cell lung cancer (NSCLC) with deletions in exon 19 (del19) or exon 21 L858R mutation. However, for first-line osimertinib the real world overall survival (OS) in mutation subgroups remains unknown. Therefore, the aim of this study was to evaluate the real-world OS of those patients treated with different generations of EGFR-tyrosine kinase inhibitors (TKI), and to identify predictors of survival.

Methods

Using real-world data from the Netherlands Cancer Registry (NCR) we assessed patients diagnosed with stage IV NSCLC with del19 or L858R mutation between January 1, 2015, and December 31, 2020, primarily treated with then regularly available TKIs (including osimertinib).

Findings

Between January 1, 2015, and December 31, 2020, 57,592 patients were included in the NCR. Within this cohort we identified 1109 patients, 654 (59%) with del19 and 455 (41%) with L858R mutations, respectively; 230 (21%) patients were diagnosed with baseline brain metastases (BM). Patients were treated with gefitinib (19%, 213/1109), erlotinib (42%, 470/1109), afatinib (15%, 161/1109) or osimertinib (24%, 265/1109). Median OS was superior for del19 versus L858R (28.4 months (95% CI 25.6-30.6) versus 17.7 months (95% CI 16.1-19.5), p < 0.001. In multivariable analysis, no difference in survival was observed between various TKIs in both groups. Only in the subgroup of patients with del19 and baseline BM, a benefit was observed for treatment with osimertinib.

Interpretation

In this nationwide real-world cohort, survival of Dutch patients with advanced NSCLC and an EGFR del19 mutation was superior versus those harboring an L858R mutation. Osimertinib performed only better as first-line treatment in patients with del19 and BM.

Funding

None.

Overview of the multifaceted resistances toward EGFR-TKIs and new chemotherapeutic strategies in non-small cell lung cancer

The role of epidermal growth factor receptor (EGFR) in non-small cell lung cancer (NSCLC) has been vastly studied over the last decade. This has led to the rapid development of many generations of EGFR tyrosine kinase inhibitors (EGFR-TKIs). However, patients treated with third-generation TKIs (osimertinib, avitinib and rociletinib) targeting the EGFR T790M mutation have shown emerging resistances and relapses. Therefore, further molecular understanding of NSCLC mutations, bypass signalling, tumour microenvironment and the existence of cancer stem cells to overcome such resistances is warranted. This will pave the way for designing novel and effective chemotherapies to improve patients' overall survival. In this review, we provide an overview of the multifaceted mechanism of resistances towards EGFR-TKIs, as well as the challenges and perspectives that should be addressed in strategising chemotherapeutic treatments to overcome the ever evolving and adaptive nature of NSCLC.

Real-world outcomes, treatment patterns and T790M testing rates in non-small cell lung cancer patients treated with first-line first- or second-generation epidermal growth factor receptor tyrosine kinase inhibitors from the Slovenian cohort of the REFLECT study

BACKGROUND

Epidermal growth factor receptor (EGFR) tyrosine kinase inhibitors (TKIs) are effective treatments for EGFR mutation-positive (EGFRm) non-small cell lung cancer (NSCLC). However, routine clinical practice is different between countries/institutions.

PATIENTS AND METHODS

The REFLECT study (NCT04031898) is a retrospective medical chart review that explored real-life treatment and outcomes of EGFRm NSCLC patients receiving first-line (1L) first-/second-generation (1G/2G) EGFR TKIs in 8 countries. This study included adult patients with documented advanced/metastatic EGFRm NSCLC with 1L 1G/2G EGFR TKIs initiated between Jan 2015 - Jun 2018. We reviewed data on clinical characteristics, treatments, EGFR/T790M testing patterns, and survival outcomes. Here, we report data from 120 medical charts in 3 study sites from Slovenia.

RESULTS

The Slovenian cohort (median age 70 years, 74% females) received 37% erlotinib, 32% afatinib, 31% gefitinib. At the time of data collection, 94 (78%) discontinuations of 1L TKI, and 89 (74%) progression events on 1L treatment were reported. Among patients progressing on 1L, 73 (82%) were tested for T790M mutation yielding 50 (68%) positive results, and 62 (85%) received 2L treatment. 82% of patients received osimertinib. Attrition rate between 1L and 2L was 10%. The median (95% CI) real-world progression free survival on 1L EGFR TKIs was 15.6 (12.6, 19.2) months; median overall survival (95% CI) was 28.9 (25.0, 34.3) months.

CONCLUSIONS

This real-world study provides valuable information about 1G/2G EGFR TKIs treatment outcomes and attrition rates in Slovenian EGFRm NSCLC patients. The reduced attrition rate and improved survival outcomes emphasize the importance of 1L treatment decision.

PET/CT Radiomic Features: A Potential Biomarker for EGFR Mutation Status and Survival Outcome Prediction in NSCLC Patients Treated With TKIs

Backgrounds

Epidermal growth factor receptor (EGFR) mutation profiles play a vital role in treatment strategy decisions for non–small cell lung cancer (NSCLC). The purpose of this study was to evaluate the predictive efficacy of baseline ¹⁸F-FDG PET/CT-based radiomics analysis for EGFR mutation status, mutation site, and the survival benefit of targeted therapy.

Methods

A sum of 313 NSCLC patients with pre-treatment ¹⁸F-FDG PET/CT scans and genetic mutations detection were retrospectively studied. Clinical and PET metabolic parameters were incorporated into independent predictors of determining mutation status and mutation site. The dataset was randomly allocated into the training and the validation sets in a 7:3 ratio. Three-dimensional (3D) radiomics features were extracted from each PET- and CT-volume of interests (VOI) singularly, and then a radiomics signature (RS) associated with EGFR mutation profiles is built by feature selection. Three different prediction models based on support vector machine (SVM), decision tree (DT), and random forest (RF) classifiers were established. Furthermore, nomograms for estimation of overall survival (OS) and progression-free survival (PFS) were established by integrating PET/CT radiomics score (Rad-score), metabolic parameters, and clinical factors. Predictive performance was assessed by the receiver operating characteristic (ROC) analysis and the calibration curve analysis. The decision curve analysis (DCA) was applied to estimate and compare the clinical usefulness of nomograms.

Results

Three hundred thirteen NSCLC patients were classified into a training set (n=218) and a validation set (n=95). Multivariate analysis demonstrated that SUVmax and sex were independent indicators of EGFR mutation status and mutation site. Eight CT-derived RS, six PET-derived RS, and two clinical factors were retained to develop integrated models, which exhibited excellent ability to distinguish between EGFR wild type (EGFR-WT), EGFR 19 mutation type (EGFR-19-MT), and EGFR 21 mutation type (EGFR-21-MT). The SVM model outperformed the RF model and the DT model, yielding training area under the curves (AUC) of EGFR-WT, EGFR-19-WT, and EGFR-21-WT, with 0.881, 0.851, and 0.849, respectively, and validation AUCs of 0.926, 0.805 and 0.859, respectively. For prediction of OS, the integrated nomogram is superior to the clinical nomogram and the radiomics nomogram, with C-indexes of 0.80 in the training set and 0.83 in the validation set, respectively.

Conclusions

The PET/CT-based radiomics analysis might provide a novel approach to predict EGFR mutation status and mutation site in NSCLC patients and could serve as useful predictors for the patients’ survival outcome of targeted therapy in clinical practice.

Uncommon EGFR mutations in lung carcinoma: features and treatment outcomes in a retrospective French cohort

Background

The best management for rare epidermal growth factor receptor (EGFR) mutations in advanced non-small cell lung carcinoma (NSCLC) remains uncertain. The literature indicates that response to usual treatment could differ in certain subgroups such as exon 20 insertion/duplication (E20ID), other single uncommon mutation (OSUM), and EGFR complex mutation (ECM).

Methods

In this observational, regional, multi-center, retrospective study, we gathered data on uncommon EGFR mutations in NSCLC from 2007 to 2021. We analyzed patient characteristics, prognostic factors and treatment outcomes [objective response rate (ORR), disease control rate (DCR), progression free survival (PFS) and overall survival (OS)].

Results

Among 119 patients with an uncommon EGFR mutant, 34 harbored E20ID, 23 ECM, and 62 OSUM. There were significantly more non-smokers in E20ID. Female gender and performance status <2 were associated with a better prognosis. Among the 97 metastatic patients with available data for 1st line treatment, median estimated OS was 21 months (95% CI: 18-31 months), with better non-significant OS for ECM. Median estimated PFS was 7 months (95% CI: 4-9 months). We found significant differences in ORR, DCR and PFS favoring 1st line chemotherapy for E20ID, whereas the outcomes for OSUM and ECM were more favorable for tyrosine kinase inhibitor (TKI) (mainly 2nd and 3rd generation).

Conclusions

There were variations in treatment outcomes among subgroups in our cohort. Exon 20 insertions showed better ORR and PFS with 1st line chemotherapy compared to TKI. Conversely, other rare EGFR mutations including ECM had better ORR and PFS with TKI than chemotherapy. There was no significant difference in OS among treatment groups overall or within rare mutation subgroups.

Insight into Targeting Exon20 Insertion Mutations of the Epidermal Growth Factor Receptor with Wild Type-Sparing Inhibitors

Despite the clinical efficacy of epidermal growth factor receptor (EGFR) inhibitors, a subset of patients with non-small cell lung cancer displays insertion mutations in exon20 in EGFR and Her2 with limited treatment options. Here, we present the development and characterization of the novel covalent inhibitors LDC8201 and LDC0496 based on a 1H-pyrrolo[2,3-b]pyridine scaffold. They exhibited intense inhibitory potency toward EGFR and Her2 exon20 insertion mutations as well as selectivity over wild type EGFR and within the kinome. Complex crystal structures with the inhibitors and biochemical and cellular on-target activity document their favorable binding characteristics. Ultimately, we observed tumor shrinkage in mice engrafted with patient-derived EGFR-H773_V774insNPH mutant cells during treatment with LDC8201. Together, these results highlight the potential of covalent pyrrolopyridines as inhibitors to target exon20 insertion mutations.

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.

Lung squamous cell carcinoma with rare epidermal growth factor receptor mutation G719X: a case report and literature review

Asians who develop non-small cell lung cancer (NSCLC) have a chance of approximately 50% of harboring the epidermal growth factor receptor (EGFR) mutation. The G719X mutation in EGFR has 3 subtypes (i.e., G719A, G719C, or G719S), all of them being classified as uncommon EGFR mutations. The EGFR mutation G719X is most often associated with lung adenocarcinoma. Conversely, its occurrence in lung squamous cell carcinoma is rare. Its response to tyrosine kinase inhibitor (TKI) treatment remains unknown. A 50-year-old Asian male with no smoking history was admitted to our hospital (Affiliated Hospital of Qingdao University) with an irritating dry cough and 1 month of progressive dyspnea. The patient was diagnosed with lung squamous cell carcinoma (cT4N3M0, stage IIIC). Lung biopsy revealed the presence of EFGR G719X mutation. The patient received a tracheobronchial stent, targeted therapy, chemotherapy, seed implantation and radiotherapy, and survived for 25.4 months following diagnosis. It is crucial that gene mutation analysis is performed in non-smoking male squamous cell carcinoma patients. Compared to lung adenocarcinoma patients with rare G719X mutation, this lung squamous cell carcinoma patient with G719X-mutant tumor had a higher sensitivity to 2^nd-generation EGFR-TKI treatment, but similar progression-free survival. Importantly, the patient clearly benefited from the used comprehensive treatment plan. This article seeks to shed light on the treatment of lung squamous cell carcinoma patients with the uncommon EGFR G719X mutation.

Afatinib for the treatment of advanced non-small-cell lung cancer harboring an epidermal growth factor receptor exon 18 E709_T710delinsD mutation: a case report

BACKGROUND

The discovery of epidermal growth factor receptor oncogenic driver mutations has changed the therapeutic landscape of advanced non-small cell lung cancer in the past decade. Since the introduction of next-generation sequencing, uncommon epidermal growth factor receptor mutations are more frequently discovered. Because seldom evaluated in clinical trials, their clinical significance and response on tyrosine kinase inhibitors are less well known.

CASE PRESENTATION

A 58-year-old Caucasian woman with no smoking history presented with advanced non-small cell lung cancer. Liver biopsy revealed an adenocarcinoma with a programmed death ligand-1 tumor proportion score of 30% and no common oncogenic driver mutations. A combination of chemotherapy and immunotherapy was started as first-line treatment. However, treatment was ceased after 18 weeks because of immune-related renal failure and disease progression. In the meantime, the next-generation sequencing results of the liver biopsy had revealed an exon 18 E709_T710delinsD mutation. Therefore, afatinib was administered, which was moderately tolerated with grade 2 paronychia and acneiform skin eruption. After 6 months, a partial response with ongoing decrease of the liver metastasis was retained.

CONCLUSION

Because of the lack of clinical trials, tumor heterogeneity, and a tyrosine kinase inhibitor affinity related to the different mutation types, it is difficult to predict the clinical outcome of tyrosine kinase inhibitor in uncommon mutations. Therefore, a therapeutic trial with tyrosine kinase inhibitor has to be considered, but the expected clinical response is lower than for common mutations.

Epidermal growth factor receptor exon 20 insertion variants in non-small cell lung cancer patients

Epidermal growth factor receptor (EGFR) exon 20 insertions occur rarely among different cancer types, with the highest frequency reported among non-small-cell lung cancer (NSCLC) patients, particularly adenocarcinomas (ADCs). Exon 20 insertions fall back in the tyrosine kinase domain, and can be clustered into two principal groups represented by in frame insertions and three to 21 bp (corresponding to 1-7 amino acids) duplications within amino acids 762 and 774. The identification of these alterations is key for an adequate management of NSCLC patients due to the possibility to treat these patients with specific targeted therapies. Next generation sequencing (NGS) technology, able to detect several hotspot gene mutations for different patients simultaneously, is the best detection approach due to its higher sensitivity and specificity compared to other techniques. Here we reviewed the principal biological characteristics, the main detection technologies and treatment options for NSCLC patients harbouring EGFR exon 20 insertions.

Therapeutic exploration of uncommon EGFR exon 20 insertion mutations in advanced non-small cell lung cancer: breaking through brambles and thorns

BACKGROUND

EGFR exon 20 insertion (EGFR ex20ins) mutations account for about 10-12% of all EGFR-mutated tumors, which are usually associated with primary drug resistance to conventional EGFR-TKI therapy and worse survival outcomes, and are currently a major problem for clinicians in clinical management. In recent years, with the rapid improvement of sequencing technology and careful review of clinical data, investigators have gained a deeper understanding and clearer cognition of the clinicopathological features and molecular mechanisms of these EGFR ex20ins mutations.

PURPOSE

The aim of this study was to systemically review the molecular structure and clinical characteristics of EGFR ex20ins mutations, and focus on summarizing the latest data of emerging therapies (including novel small-molecule EGFR-TKI drugs, specific monoclonal antibodies, novel drugs targeting other mechanisms, and immunotherapy) for those patients.

CONCLUSION

Advances in overcoming these systemic challenges have greatly accelerated the development of new drugs targeting EGFR ex20ins, and are committed to designing more rational combination therapies to overcome or delay the emergence of drug resistance, ultimately improve the prognosis of such uncommon mutant populations.

[Current Advance in Targeted Treatment and Immunotherapy for BRAF-mutant Advanced Non-small Cell Lung Cancer]

随着精准医学的发展，靶向驱动基因的治疗显著改善了晚期非小细胞肺癌（non-small cell lung cancer, NSCLC）患者的预后和生活质量。其中鼠类肉瘤病毒癌基因同源物B1（v-raf murine sar-coma viral oncogene homolog B1, BRAF）基因突变的NSCLC较为罕见，传统治疗遵循无驱动基因突变NSCLC的治疗方案，远远没有满足临床需求。近年来，针对BRAF V600E突变NSCLC的靶向治疗疗效显著，其他BRAF突变亚型靶向治疗仍在探索阶段。免疫疗法在BRAF V600E和非V600E亚型的NSCLC中也显示出积极的抗肿瘤活性。本文就BRAF阳性NSCLC患者的靶向和免疫治疗研究进展作一综述。

Molecular Mechanism of EGFR-TKI Resistance in EGFR-Mutated Non-Small Cell Lung Cancer: Application to Biological Diagnostic and Monitoring

Non-small cell lung cancer (NSCLC) is the most common cancer in the world. Activating epidermal growth factor receptor (EGFR) gene mutations are a positive predictive factor for EGFR tyrosine kinase inhibitors (TKIs). For common EGFR mutations (Del19, L858R), the standard first-line treatment is actually third-generation TKI, osimertinib. In the case of first-line treatment by first (erlotinib, gefitinib)- or second-generation (afatinib) TKIs, osimertinib is approved in second-line treatment for patients with T790M EGFR mutation. Despite the excellent disease control results with EGFR TKIs, acquired resistance inevitably occurs and remains a biological challenge. This leads to the discovery of novel biomarkers and possible drug targets, which vary among the generation/line of EGFR TKIs. Besides EGFR second/third mutations, alternative mechanisms could be involved, such as gene amplification or gene fusion, which could be detected by different molecular techniques on different types of biological samples. Histological transformation is another mechanism of resistance with some biological predictive factors that needs tumor biopsy. The place of liquid biopsy also depends on the generation/line of EGFR TKIs and should be a good candidate for molecular monitoring. This article is based on the literature and proposes actual and future directions in clinical and translational research.

EGFR Exon 18 Mutations in Advanced Non-Small Cell Lung Cancer: A Real-World Study on Diverse Treatment Patterns and Clinical Outcomes

Background

Approximately 3–5% of patients with epidermal growth factor receptor (EGFR) mutation-positive non-small cell lung cancer (NSCLC) harbor exon 18 mutations. The appropriate treatment for such patients has not been clarified. The aim of this study was to investigate the response of patients with NSCLC harboring EGFR exon 18 mutations to different therapeutic options.

Methods

Between May 2014 and September 2020, the clinical outcomes of 82 patients harboring EGFR exon 18 mutations who received first-generation (1G) EGFR-tyrosine kinase inhibitor (TKI), second-generation (2G) EGFR-TKI afatinib, chemotherapy, and 1G TKI in combination with chemotherapy as the initial therapy were retrospectively analyzed.

Results

A total of 82 NSCLC patients harboring EGFR 18 mutations with whose treatment and survival outcomes were available were analyzed. The median age was 59 years, and 47 (57.3%) were female. The most common kind of EGFR exon 18 mutation was G719X (75.6%), followed by E709X (15.9%), E709_T710delinsD (3.6%), and other subtypes (4.9%). There was a significant difference in median progression-free survival (mPFS) by therapeutic strategy (P = 0.017). The mPFS of 1G TKI, 2G TKI afatinib, chemotherapy, and 1G TKI in combination with chemotherapy were 7.7 (95% CI, 4.2–11.2), 11.3 (95% CI, 5.6–17.0), 5.0 (95% CI, 2.3–17.7), and 11.1 (95% CI, 5.9–16.4) months, respectively. No significant difference in PFS was observed between afatinib and 1G TKI in combination with chemotherapy (P = 0.709).

Conclusions

Like afatinib, 1G TKI in combination with chemotherapy might be an effective treatment option for patients harboring EGFR exon 18 mutations.

Pembrolizumab and chemotherapy in non-small cell lung cancer with EGFR ex20ins mutation: A case report

The efficacy of immunotherapy in non‐small cell lung cancer (NSCLC) with uncommon epidermal growth factor receptor (EGFR) mutations is not well clarified, even though immunotherapy has brought revolutionary improvements in EGFR wild‐type NSCLC. In addition, pseudoprogression has increased the difficulty in immunotherapy management and data on the incidence of pseudoprogression in patients with EGFR exon 20 insertions (ex20ins) is rarely reported. Here, we discuss the case of an advanced lung adenocarcinoma patient with EGFR ex20ins alteration. The patient received pembrolizumab plus chemotherapy as first‐line therapy and disease control was achieved. Progression‐free survival (PFS) was 9 months. The patient was subsequently treated with pembrolizumab plus docetaxel and bevacizumab as second‐line therapy and the disease remained stable. After two cycles of first‐line treatment, the patient showed improvement in performance and the primary left upper lung lesion was stable; however, there was an increase in size as well as number of small diffuse bilateral pulmonary nodules. Therapy was maintained with the original regimen and complete regression of the bilateral lung nodules was achieved after a third cycle of treatment. Pseudoprogression was diagnosed. In the case reported here, we advocate the use of a PD‐L1 inhibitor plus conventional chemotherapy in advanced NSCLC patients harboring EGFR ex20ins mutation and hope that our experience might be beneficial to other clinicians in distinguishing pseudoprogression from true progression.

c-Src Increases the Sensitivity to TKIs in the EGFR-Mutant Lung Adenocarcinoma

c-Src and the epidermal growth factor receptor (EGFR) are key apical kinases that govern cell responses to microenvironmental cues. How c-Src affects EGFR-related signaling and targeted therapy remains elusive. Initially, caspase-8 phosphorylated at tyrosine 380 by c-Src predominantly enhancing c-Src activation to facilitate metastasis through attaining epithelial-mesenchymal transition (EMT) phenotype in lung adenocarcinoma. Mechanistically, the linkage of c-Src SH2 domain with phosphotyrosine 380 of caspase-8 and SH3 domain with “PDEP” motif of caspase-8 overactivates c-Src as compared with other c-Src-partner proteins. c-Src is incapable of triggering EGFR-related signaling. This is reflected by the levels of phosphotyrosine 1068, 1086, and 1145, which have no impact on c-Src activation. Tyrosine kinase inhibitors (TKIs) suppress EGFR-related signaling to yield cell deaths of lung adenocarcinoma by both necroptosis and intrinsic apoptosis. Given that c-Src activation is frequent in lung adenocarcinoma, blocking c-Src activation through dasatinib can seal the survival-signaling-related phosphotyrosines of EGFR by its SH2 domain, which in turn increases the antitumor activity of TKIs in EGFR-mutant lung adenocarcinoma. Collectively, c-Src inactivation by dasatinib administration sensitizes EGFR-mutant lung adenocarcinoma to TKIs.

The treatment of advanced lung adenocarcinoma with activating EGFR mutations

INTRODUCTION

Lung adenocarcinomas account for approximately 40-50% of all NSCLC (Non-Small Cell Lung Cancer) cases. In addition, lung adenocarcinomas can harbor several different genetic mutations, EGFR (Epidermal Growth Factor Receptor) being the most frequent one, accounting for approximately 5-15% of all the mutations in western patients and for approximately 40-55% in Asian patients; on the other hand, EGFR mutations are uncommon in squamous histology. Approximately 90% of EGFR mutations are represented by exon 19 in-frame deletion and by the L858R exon 21-point mutation, that confer sensitivity to EGFR TKI (Tyrosine Kinase Inhibitors) treatment.

AREAS COVERED

The authors comprehensively review the current state of the art with reference to EGFR+ NSCLC treatment and to discuss the possible future developments.

EXPERT OPINION

Osimertinib must be considered the preferred first-line agent in EGFR+ advanced NSCLC patients thanks to its superior performances. With respect to acquired resistance mechanisms to osimertinib, the currently ongoing clinical trials will surely help us to better understand and tackle them. Globally, we strongly believe that a biomarker-driven sequential treatment algorithm is key in order to provide personalized, effective and durable therapies in the increasingly complex landscape of EGFR+ advanced NSCLC.

A Nationwide Study on the Impact of Routine Testing for EGFR Mutations in Advanced NSCLC Reveals Distinct Survival Patterns Based on EGFR Mutation Subclasses

EGFR mutation analysis in non-small-cell lung cancer (NSCLC) patients is currently standard-of-care. We determined the uptake of EGFR testing, test results and survival of EGFR-mutant NSCLC patients in the Netherlands, with the overall objective to characterize the landscape of clinically actionable EGFR mutations and determine the role and clinical relevance of uncommon and composite EGFR mutations. Non-squamous NSCLC patients diagnosed in 2013, 2015 and 2017 were identified in the Netherlands Cancer Registry (NCR) and matched to the Dutch Pathology Registry (PALGA). Overall, 10,254 patients were included. Between 2013-2017, the uptake of EGFR testing gradually increased from 72.7% to 80.9% (p < 0.001). Multi-gene testing via next-generation sequencing (increased from 7.8% to 78.7% (p < 0.001), but did not affect the number of detected EGFR mutations (n = 925; 11.7%; 95% confidence interval (CI), 11.0-12.4) nor the distribution of variants. For patients treated with first-line EGFR inhibitors (n = 651), exon 19 deletions were associated with longer OS than L858R (HR 1.58; 95% CI, 1.30-1.92; p < 0.001) or uncommon, actionable variants (HR 2.13; 95% CI, 1.60-2.84; p < 0.001). Interestingly, OS for patients with L858R was similar to those with uncommon, actionable variants (HR 1.31; 95% CI, 0.98-1.75; p = 0.069). Our analysis indicates that grouping exon 19 deletions and L858R into one class of 'common' EGFR mutations in a clinical trial may mask the true activity of an EGFR inhibitor towards specific mutations.

Cancer-elicited inflammation attenuates response and outcome in tyrosine kinase inhibitor naive patients with advanced NSCLC

OBJECTIVE

Cancer elicited inflammation is the main environmental cause leading to carcinogenesis and metastasis of non-small cell lung cancer (NSCLC). Roles of the inflammatory biomarker in predicting the clinical efficacy of tyrosine kinase inhibitor (TKI) and prognosis of naive patients with advanced NSCLC need to be determined, and the best inflammatory predicted biomarker remains unknown.

METHODS

A total of 178 eligible advanced NSCLC patients (124 and 54 cases within discovery and validation cohorts, respectively) who received first-line EGFR-TKI between July of 2014 and October of 2020 were enrolled in the present study. We detected circulating immune cell counting, albumin (Alb), pre-albumin (pAlb), ALP, AST, LDH, GGT, HDL-c, and fibrinogen (Fib) concentrations, and calculated 22 inflammatory ratios and scores. Logistic regression and Cox proportional hazards models were used to assess the impact of these ratios and scores on objective response and disease control rate (ORR and DCR) as well as progression-free survival (PFS) in these patients.

RESULTS

Twenty-five percentage and 24.07% of NSCLC patients were observed objective response to the treatment of first-line EGFR-TKI in discovery and validation cohort, respectively. Univariate and multivariate Cox regression showed that high PLR, NPS, SII, SIS, mSIS, GLR and FPR as well as low PNI were significantly associated with poor PFS in discovery cohort. However, only high SII and FPR were found to be associated with unsatisfactory outcome in validation cohort. Time-dependent areas under ROC of FPR were 0.702 (0.517-0.888) in discovery cohort, and 0.767 (0.613-0.921) in validation cohort, which were extremely higher than the other biomarkers. The patients with FPR-SII combined score 2 harbored worse prognosis compared to the combined score 0 in discovery (p_log-rank = 0.003, adjusted HR = 2.888, 95%CI = 1.500-5.560) and validation cohort (p_log-rank = 0.001, adjusted HR = 3.769, 95%CI = 1.676-8.478) as well as overall population (p_log-rank < 0.001, adjusted HR = 3.109, 95%CI = 1.878-5.147), and its time-dependent AUCs were 0.747 (0.594-0.900) and 0.815 (0.688-0.942) in the two cohorts, respectively, which were significantly higher than the single biomarker in the two cohorts. The patients with high FPR and FPR-SII score harbored worse DCR than the low patients in the two cohorts and overall population, respectively. Moreover, the similar poor survival was observed in advanced high-FPR NSCLC patients with different treatment options, however, the survival of low-FPR patients with treatment of single TKI, radiotherapy or chemotherapy or radio-chemotherapy combined TKI was good compared to the high-FPR patients with radio-chemotherapy combined TKI, and the survival differences were observed between TKI (p_log-rank < 0.001) or radiotherapy combined TKI (p_log-rank = 0.014) treated low-FPR patients and the high FPR patients. Additionally, FPR-SII combined score could monitor the progression of the disease in real-time, and the median month of the positive score appearance was significantly earlier than CT/MRI detection (p < 0.001 for 3 months vs. 13 months).

CONCLUSIONS

High-grade cancer elicited inflammation could attenuates response and outcome in tyrosine kinase inhibitor naive patients with advanced NSCLC. FPR-SII combined score was the best inflammatory biomarker to monitor and predict the progression of advanced NSCLC patients with treatment of TKI.

Real-World Treatment Patterns, Epidermal Growth Factor Receptor (EGFR) Testing and Outcomes in EGFR-Mutated Advanced Non-small Cell Lung Cancer Patients in Belgium: Results from the REVEAL Study

BACKGROUND

Treatment of patients with epidermal growth factor receptor-mutated (EGFRm) non-small cell lung cancer (NSCLC) continues to evolve expeditiously.

OBJECTIVES

This retrospective study investigated real-world treatment patterns and EGFR mutation testing in patients with EGFRm advanced NSCLC in Belgium.

METHODS

Data were extracted from medical records of adults diagnosed with EGFRm locally advanced/metastatic NSCLC between 1 September 2015 and 31 December 2017. Patients were followed retrospectively from diagnosis until 1 September 2018, end of clinical activity or death. Data on demographics, patient outcomes and disease characteristics, treatment patterns and EGFR mutation testing at diagnosis and progression were analyzed descriptively.

RESULTS

A total of 141 patients were enrolled. At diagnosis, median age was 69 years, 63.1% were female, 88.7% had metastatic disease, 94.3% had adenocarcinoma histology, 76.6% had ECOG 0/1, 70.9% had common EGFR mutations and 29.1% had only rare mutations. In first line, 73.8% of patients received first/second-generation EGFR-tyrosine kinase inhibitors (1G/2G EGFR-TKIs), while 21.9% received other systemic treatments. Among 61 patients progressing on and discontinuing a first 1G/2G EGFR-TKI, 45 (73.8%) received subsequent systemic treatment while 16 (26.2%) did not; 20 (32.8%) received osimertinib. Among 65 patients progressing on a first 1G/2G EGFR-TKI, 47 (72.3%) were tested for T790M, of whom 25 (53.2%) were positive.

CONCLUSION

These real-world data from Belgium show that a substantial fraction of patients with EGFRm NSCLC do not receive 1G/2G EGFR-TKIs in first line and do not receive subsequent systemic treatment after progression on 1G/2G EGFR-TKIs. Only a third receive osimertinib upon progression on 1G/2G EGFR-TKIs. These observations should be considered in first-line treatment decisions.

TRIAL REGISTRATION

ClinicalTrials.gov: NCT03761901-December 3, 2018.

EGFR Exon 20 Insertion Mutations: Clinicopathological Characteristics and Treatment Outcomes in Advanced Non-Small Cell Lung Cancer

BACKGROUND

Epidermal growth factor receptor gene (EGFR) exon 20 insertion (ex20-ins) mutations are an uncommon and heterogeneous group of non-small cell lung cancers (NSCLCs), resistant to conventional EGFR tyrosine kinase inhibitors (TKIs). Characteristics and outcomes of patients with EGFR ex20-ins have not been fully established; we sought to clarify them using a multinational patient database.

PATIENTS AND METHODS

Patients with NSCLC from six Australian institutions with EGFR exon 20 mutations (ex20-mut), excluding T790M, were retrospectively reviewed. Clinical characteristics and outcomes with systemic treatments were collected and analyzed using comparative statistics.

RESULTS

Among 109 patients with ex20-mut, 61% were females and 75% were Caucasians. More males presented with de novo metastatic disease (84% vs. 51%; P = .002). Central nervous system (48%) and liver (24%) metastases were common within metastatic patients (n = 86). Thirty-nine patients received platinum-based chemotherapy (PBC) and achieved a 43% objective response rate (ORR), median progression-free survival (mPFS) of 6.9 months, and median overall survival (mOS) of 31.0 months. Twenty-three of the patients with ex20-ins received conventional TKIs, resulting in an ORR of 13%, mPFS of 3.4 months (95% confidence interval [CI], 1.91-6.25), and mOS of 31.0 months (95% CI, 15.09-not reached). Nine patients with S786I mutations received TKIs, resulting in an ORR of 50%, mPFS of 18.2 months (2.79-not reached), and mOS of 33.4 months (95% CI, 16.14-not reached). Twenty-three patients received immune checkpoint inhibitor monotherapy (ICIm), resulting in an ORR of 4%, mPFS of 2.6 months (95% CI, 1.91-4.83), and mOS of 30.8 months (95% CI, 17.62-41.62).

CONCLUSION

Although phenotypically similar to patients with common EGFR mutations, patients with EGFR ex20-mut had worse survival, perhaps due to the lack of targeted therapies. Chemotherapy was superior to conventional EGFR TKIs in patients with EGFR ex20-ins, although there was moderate activity of TKIs in S768I mutations. ICIm was ineffective.

Tackling Drug Resistance in EGFR Exon 20 Insertion Mutant Lung Cancer

Insertion mutations in exon 20 (Ex20ins) of the epidermal growth factor receptor (EGFR) gene are the largest class of EGFR mutations in non-small cell lung cancer (NSCLC) for which there are currently no approved targeted therapies. NSCLC patients with these mutations do not respond to clinically approved EGFR tyrosine kinase inhibitors (TKIs) and have poor outcomes. A number of early phase clinical trials are currently underway to evaluate the efficacy of a new generation of TKIs that are capable of binding to and blocking Ex20ins. Although these agents have shown some clinical activity, patient responses have been restricted by dose-limiting toxicity or rapid acquisition of resistance after a short response. Here we review the current understanding of the mechanisms of resistance to these compounds, which include on-target EGFR secondary mutations, compensatory bypass pathway activation and acquisition of an EMT phenotype. Taking lessons from conventional EGFR inhibitor therapy in NSCLC, we also consider other potential sources of resistance including the presence of drug-tolerant persister cells. We will discuss therapeutic strategies which have the potential to overcome different forms of drug resistance. We conclude by evaluating recent technological developments in drug discovery such as PROTACs as a means to better tackle TKI resistance in NSCLC harbouring Ex20ins mutations.

Predictive molecular pathology in non-small cell lung cancer in France: The past, the present and the perspectives

The advent of molecular targets for novel therapeutics in oncology, notably for non-small cell lung carcinoma (NSCLC), led the French National Cancer Institute (INCa) to establish a national network of 28 hospital Molecular Genetics Centers for Cancer (MGCC) in 2007. In each University in France, laboratories were established to develop molecular biology testing to evaluate a few genomic alterations, initially a selection of genes, by using specific targeted polymerase chain reaction (PCR) assays. In a second phase, the number of studied genes was increased. In 2015, the MGCC benefited from an additional dedicated budget from the INCa to develop next-generation sequencing (NGS) technology. In the meantime, a new financial regulation for innovative testing has been established for the acts out of nomenclature. Consequently, all private and public laboratories in France have access to funding for molecular biology testing in oncology. The gene-based PCR assays or NGS tests have benefitted from reimbursement of cost testing by the INCa. Today, the laboratories consider this reimbursement to be only partial, and its use to be complex. In 2018, a strategic plan for medical genomic analyses (France Médecine Génomique 2025) was implemented to introduce more systematic sequencing into the health care pathway and oncology practice. The large panel of molecular tests should be centralized to a limited number of molecular genetic centers. This review describes the evolution of the different stages of implementation of molecular pathology testing for NSCLC patients over the last few years in France.

Clinical influence of switching companion diagnostic tests for EGFR-TKs from Therascreen to Cobas v2

Background

Several companion diagnostic (CDx) tests for epidermal growth factor receptor tyrosine kinase inhibitors (EGFR‐TKIs) have been approved. In our institute, the CDx test for EGFR‐TKIs was changed from the Therascreen test (Therascreen) to the Cobas EGFR v2 test (Cobas) because only Cobas was approved for the use of osimertinib in patients with EGFR‐mutated non‐small cell lung cancer (NSCLC) with T790M mutations. The clinical influence of switching the CDx test has not yet been examined comprehensively.

Methods

All serial patients with lung cancer tested for EGFR mutations with CDx tests between February 2014 and February 2016 at the Cancer Institute Hospital of the Japanese Foundation for Cancer Research (JFCR) were enrolled in this analysis.

Results

Therascreen was used as a CDx test for EGFR‐TKI therapy in 607 patients between February 2014 and January 2015, and Cobas was used in 621 patients between February 2015 and February 2016. EGFR mutations were detected in 218 patients (35.9%) and 244 patients (39.3%) tested with Therascreen and Cobas, respectively. At the initial diagnosis, 400 and 459 patients were tested with Therascreen and Cobas, respectively. EGFR mutation subtypes, including del19, L858R, and others, were detected in 13.0%, 17.0%, and 2.5% of patients using Therascreen and 17.4%, 14.4%, and 1.5% of patients using Cobas, respectively.

Conclusions

No significant impact of switching from Therascreen to Cobas as the CDx test for EGFR mutations in clinical practice was observed. However, the detection pattern of the EGFR mutation subtypes between the two CDx tests was slightly different.

Key points

Significant findings of the study

We examined the influence of changing the EGFR test in 1228 patients in total. The detection rate of EGFR mutations was similar. However, the detection pattern for EGFR subtype mutations was slightly different between the two tests.

What this study adds

Switching CDx tests from target polymerase chain reaction (PCR)‐ to next‐generation sequencing (NGS)‐based methods may lead to obvious changes in clinical practice. When the CDx test is required to change, the investigation of this influence is warranted in future studies.

Almonertinib-induced interstitial lung disease: A case report

RATIONALE

Epidermal growth factor receptor-tyrosine kinase inhibitors (EGFR-TKIs) have elicited favorable anti-tumor activity in non-small cell lung cancer especially the lung adenocarcinoma. Interstitial lung disease (ILD) is 1 of the fatal side effects of EGFR-TKIs. However, such type of side effect has not been observed in the follow-up during the treatment of the third-generation EGFR-TKI Almonertinib (also called HS-10296). Here, we first report an Almonertinib-induced ILD in an elderly female patient.

PATIENT CONCERNS

A 70-year-old female diagnosed with " lung adenocarcinoma with intracranial metastasis" harboring a mutation of EGFR 19DEL was administrated with Almonertinib 110 mg orally as the first-line treatment. However, she presented with chest tightness, and shortness of breath, accompanying with paroxysmal dry cough 3 months after the initiation of Almonertinib.

DIAGNOSES

Extensive relevant examinations did not provide conclusive results and the chest computed tomography showed a diffuse ILD in bilateral pulmonary.

INTERVENTIONS

The patient was diagnosed with Almonertinib-induced ILD in the absence of no other potential causes. She discontinued Almonertinib and was treated with oxygen uptaken and methylprednisolone.

OUTCOMES

The whole symptoms were eliminated and the chest computed tomography showed ILD got remission after the prescription of methylprednisolone.

LESSONS

Almonertinib has potential to cause the rare but severe interstitial lung disease. Clinicians should keep cautious of this when prescribing Almonertinib.

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.

Long term follow-up of EGFR mutated NSCLC cases

PURPOSE

A substantial fraction of all non-small cell lung cancers(NSCLC) carry a mutation in the EGFR gene for which an effective treatment with anti-tyrosine kinases(TKIs) is available. We studied the long term survival of these patients following the introduction of TKIs.

EXPERIMENTAL DESIGN

All consecutive cases of NSCLC newly diagnosed with advanced disease were referred for free tumor EGFR mutation testing at Clalit's national personalized medicine laboratory. Mutations and deletions in target codons 18-21 of EGFR were sought using RT-PCR and fragment analysis. Comprehensive EMRs were used to collect full data on treatments and clinical status.

RESULTS

A cohort of 3,062 advanced NSCLC cases, included 481(15.7%) somatic EGFR mutation carriers (17.5% of all adenocarcinomas, 26.7% of females with adenocarcinomas). TKIs treatment to EGFR mutation carriers was provided to 85% of all eligible. After a median follow up period of 15.9 months for EGFR mutated cases the hazard ratio for overall survival of EGFR-mutated NSCLC treated with TKIs was 0.55(0.49-0.63, p<0.0001) when compared with EGFR wild-type(WT) tumors under usual care. After adjusting for age, sex, ethnicity, smoking history and tumor histology, all of which had an independently significant effect on survival, the HR for TKI-treated, EGFR-mutated tumors, was 0.63 (0.55-0.71, p<0.0001). Treating EGFR-WT cases with TKIs yielded a high HR=1.32 (1.19-1.48).

CONCLUSIONS

TKIs given to EGFR mutated advanced NSCLC demonstrated a substantial survival benefit for at least five years. Squamous histology, smoking, male sex and Arab ethnicity were associated with higher NSCLC mortality hazard. Treating non-EGFR-mutated NSCLC with TKIs seems detrimental. Statement of Significance: • TKIs given to EGFR mutated advanced NSCLC demonstrated a substantial survival benefit for at least five years but not much longer. • Treating non-EGFR-mutated NSCLC with TKIs seems detrimental and should probably be avoided. • Squamous histology of non-small cell lung cancer, smoking history, male sex and Arab ethnicity were associated with altogether higher NSCLC mortality hazard.

Real world data of efficacy and safety of erlotinib as first-line TKI treatment in EGFR mutation-positive advanced non-small cell lung cancer: Results from the EGFR-2013-CPHG study

BACKGROUND

Phase III clinical trials have demonstrated the merits of epidermal growth factor receptor (EGFR)-tyrosine kinase inhibitors (TKI) in the treatment of non-small cell lung cancer (NSCLC) patients with EGFR-activating mutations. Using a cohort of unselected patients treated with erlotinib, we sought to further describe patient and tumour characteristics, and to evaluate their progression-free survival (PFS) and overall survival (OS).

METHODS

Overall, 44 pulmonologists included patients with the required characteristics as follows: Stage IIIB-IV NSCLC, EGFR-activating mutation, age≥18 years, and having to start erlotinib therapy or receiving erlotinib therapy as the first-line TKI, regardless of treatment-line. The analyses were performed using R software, with survival rates calculated according to the Kaplan-Meier method.

RESULTS

A total of 177 patients, aged 72 years on average, were enrolled over a 2-year period. The cohort included 123 women (69.5%), 158 Caucasians (89.3%), 112 non-smokers (63.2%), and 167 adenocarcinomas (94.3%), at either stage IIIB (21) or IV (156), with a good performance status (PS 0-1, 127). Overall, 40 exhibited brain metastases at baseline (22.6%), while 75 had undergone earlier treatment (42.4%). Median PFS was 11.7 months and OS 25.8 months, with respectively a 1-year rate of 48.6% and 74%. The risk of death correlated with ECOG status (PS=2, HR=4.48, P<0.001) but not with brain metastasis (HR=1.67, P=0.278).

CONCLUSIONS

This study has confirmed erlotinib's efficacy and safety for unselected patients, with PFS and OS comparable to those obtained in phase III trials.

Uncommon EGFR mutations in lung adenocarcinoma: features and response to tyrosine kinase inhibitors

Background

EGFR mutant non-small cell lung cancer (NSCLC) is a heterogeneous disease. The treatment for frequent EGFR mutations relies on tyrosine kinase inhibitors (TKIs); the clinical and therapeutic significance of uncommon EGFR mutations is uncertain.

Methods

This is a single-center retrospective study of patients with EGFR-mutant lung cancer (2009-2017). Molecular analyses of EGFR exons 18-21 were performed. Only patients with uncommon mutations were included (p.Glu709X, p.Gly719X, p.Ala767_Val769 dup, p.Ser768Ile, and p.Leu861Gln).

Results

Among 6,747 tumor samples, 95 out 820 patients (11.6%) harbored 113 uncommon EGFR mutations. There were 50 metastatic NSCLC patients for whom the median OS was 18.0 months (95% CI: 15, 32). In this population, the p.Leu861Gln uncommon exon 21 EGFR mutation was associated with poor prognosis (HR: 2.96, 95% CI: 1.39, 6.31; P=0.003). Among those harboring a single uncommon EGFR mutation, median OS was 27.6 months (95% CI: 10.8, not attained) in patients who were treated by chemotherapy only (n=13) versus 6.0 months (95% CI: 2.4, not attained) in patients exclusively treated with a first or second-EGFR-TKI (n=9; HR: 0.27, 95% CI: 0.09, 0.78; P=0.01. In patients with a single uncommon EGFR mutation, first-line chemotherapy was associated with a better overall survival than TKIs (HR: 0.31, 95% CI: 0.15, 0.68; P=0.002). In patients who received first or second-EGFR-TKI as first-line treatment (n=26), OS was significantly better for those with two uncommon EGFR mutations than those with a single uncommon mutation (HR: 0.07, 95% CI: 0.009, 0.54; P=0.001).

Conclusions

In conclusion, uncommon EGFR mutations may be associated with a poor outcome and the data challenge the use of first-generation TKI in such patients, however first-line TKI is more effective in cases of double uncommon mutations and such patients should be treated accordingly.

Detection of somatic TP53 mutation in surgically resected small-cell lung cancer by targeted exome sequencing: association with longer relapse-free survival

OBJECTIVES

Few reports have explored clinical biomarkers, including those identified by targeted exome sequencing (TES) of surgically resected small-cell lung cancer (SCLC) and correlation with patient survival.

PATIENTS AND METHODS

We collected formalin-fixed paraffin-embedded tumor samples from 127 patients with SCLC who had undergone surgery and analysed nonsynonymous somatic gene mutation profiles by TES of 26 cancer-related genes using next-generation sequencing (NGS) and web databases (UMIN Registration No. 000010117).

RESULTS

We detected 38 nonsynonymous somatic tumor protein p53 (TP53) mutations in 43 (54.4%) patients. Among these TP53 lesions, we identified clinically relevant mutations including those encoding Y220C, R248W, R249M, M237I, and R273L substitutions in the p53 protein. These mutations have been reported to be associated with certain clinical outcomes or biology in other types of malignancies but not in SCLC. Moreover, nonsynonymous somatic mutations of TP53 were positively associated with relapse-free survival (RFS) (median, 17.33 months [95% confidence interval (CI), 3.86-30.79] in a mutation-positive group vs 10.39 months (6.96-13.82) in a mutation-negative group, p = 0.042). Multivariate analysis revealed that nonsynonymous somatic TP53 mutation was an independent factor of prolongation of RFS (hazard ratio: 0.51, 95% CI: 0.29-0.89, p = 0.019) but not overall survival (OS).

CONCLUSION

These data suggested that TES may play a critical role for promoting reverse-translational studies, including investigations of the biology of TP53 mutations in different stages of SCLC. Accumulation of the data using cancer panels with a broader range of genes, including TP53, is expected to be useful for future clinical applications for patients with SCLC.

EGFR mutation-positive NSCLC: factors to consider when deciding first-line therapy

Introduction: Advanced non-small-cell lung cancers with EGFR mutation belong to the models of solid tumors which revealed the concept of oncogene addiction. For that reason, first, second and third generation EGFR tyrosine kinase inhibitors (TKIs) are the major anti-cancer drugs used in this indication. Translational research is currently focused on induced mechanisms of resistance and aims to define the best first therapeutic option and the best multiline strategy.Areas covered: EGFR TKIs, alone or in combination, i.e. anti-angiogenic drugs or chemotherapy, have demonstrated their ability to improve median PFS and OS in large randomized phase 3 trials. All these combinations, now available in first-line for EGFR mutated advanced NSLC, need to integrate multiple factors like patients characteristics (age, co-morbidities, eligibility to platinum-based chemotherapy), presence of brain metastasis at diagnosis, and type of EGFR mutation. This review has 2 aims: (1) to discuss the current knowledge of therapies available in non pre-treated EGFR-mutated NSCLC; (2) to propose the best therapeutic option according to multiple parameters, either clinical or biological.Expert commentary: In 2020, we can affirm that osimertinib the first choice for patients with EGFR-mutated NSCLC. However, this has to be balanced with patient characteristics, type of EGFR mutation and new therapeutic options.

Determining the appropriate treatment for different EGFR mutations in non-small cell lung cancer patients

Introduction: Epidermal growth factor receptor (EGFR) mutations occur in a significant fraction of non-small cell lung cancer (NSCLC) patients. Most common activating mutations are in-frame deletion in exon 19 and point mutation in exon 21. EGFR tyrosine kinase inhibitors (TKIs) represent standard of care of EGFR mutated patients bearing common mutations. Therapy for individuals carrying uncommon mutations, such as G719X, L861Q, S768I, is less defined and few options exist for individuals harboring EGFR exon 20 mutations. In all mutated patients, drug resistance remains the most critical clinical problem and new agents and strategies are under investigation.Areas covered: We have reviewed the current status of NSCLC EGFR mutated treatment by analyzing data from preclinical studies, clinical prospective and retrospective trials in order to analyze current and future options for patients harboring different EGFR mutations.Expert opinion: At the present time, available data demonstrated that osimertinib is the best EGFR-TKI for front-line therapy. Other agents, such as dacomitinib, and new drug combinations, such as regimens including anti-angiogenic agents or chemotherapy, demonstrated to significantly prolong progression-free survival or overall survival, representing potential alternative to osimertinib. Many questions remain opened, including best drug sequencing and needing of new therapeutic approaches extending patient survival and cure rate.

The significance of epidermal growth factor receptor uncommon mutations in non-small cell lung cancer: A systematic review and critical appraisal

Uncommon epidermal growth factor receptor (EGFR) mutations collectively account for 10% of EGFR mutations, harboring heterogeneous molecular alterations within exons 18-21 with clinically variable responses to EGFR tyrosine kinase inhibitors (TKIs) in advanced Non-Small Cell Lung Cancer (NSCLC) patients. In addition, with the introduction of different NGS gene approach an improvement of EGFR mutations detection was reported. Today, no specific studies have prospectively evaluated uncommon sensitizing mutations in detail and no firm standard of care has been established in the first-line setting. The aim of this comprehensive review is to critically consider the clinical role of uncommon EGFR mutations highlighting the results of several in vitro and in vivo studies, which singly evaluated the sensitivity of uncommon mutations to currently European of Medicines Agency (EMA)-approved EGFR TKIs in cell lines, xenograft models and humans, in order to obtain a practical guide for refining the clinical decision-making process.

Rapid detection of EGFR mutations in decalcified lung cancer bone metastasis

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Molecular status determination following decalcification procedures is challenging.

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The Idylla™ EGFR assay demonstrates good performance on decalcified bone samples.

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The choice of EGFR assay should be adapted to patient and sample specificities.

Detection of molecular alterations in lung cancer bone metastasis (LCBM) is particularly difficult when decalcification procedure is needed. The Idylla™ real-time (RT)-PCR is compared to the routine method used in our laboratory, which combines next generation and Sanger sequencing, for the detection of EGFR mutations in LCBM.

LCBM subjected to EDTA or formic acid decalcification were analysed for EGFR mutational status using two methods: first, the Ion Torrent Ampliseq next generation sequencing (NGS) assay +/- Sanger sequencing was used prospectively; then, the fully-automated, RT-PCR based molecular testing system Idylla™ EGFR Mutation Test was applied retrospectively.

Out of the 34 LCBM assayed, 14 (41.2%) were unsuitable for NGS analysis and five remained unsuitable after additional Sanger EGFR sequencing (5/34, 14.7%). Using Idylla™, valid results were observed for 33/34 samples (97.1%). The concordance between the NGS +/- Sanger sequencing method and the RT-PCR method was 89.7% (26/29), one false positive EGFR S768I mutation and two false negative results were observed using Idylla™; one of these false negative cases was diagnosed by Sanger sequencing with a rare exon 19 EGFR mutation not covered by the Idylla™ EGFR Mutation Test design.

Detection of EGFR mutations in decalcified LCBM is challenging using NGS, more than half of samples showing invalid results. Alternative methods should thus be preferred to spare clinical samples and decrease delay. The Idylla™ EGFR Mutation Test shows a good performance on decalcified bone samples and could be used as a first step. In case of negative results, a sequencing approach is mandatory to check the presence of rare EGFR mutations sensitive to EGFR tyrosine kinase inhibitors.

Efficacy of early combination of local radiotherapy and GM-CSF for advanced non-small cell lung cancer treated with icotinib

BACKGROUND

Lung cancer is a disease that severely endangers human health. Non-small cell lung cancer (NSCLC) accounts for approximately 4/5 of lung cancers.

AIMS

To investigate the efficacy of early combination of local radiotherapy and granulocyte macrophage colony-stimulating factor (GM-CSF) for advanced NSCLC treated with icotinib.

METHODS

Forty-two patients with stage IV NSCLC complicated with EGFR gene mutation were selected and randomly divided into two groups, with 21 patients in each group. Patients in control group were treated with icotinib, and patients in experimental group were treated with icotinib combined with local radiotherapy and subcutaneous injection of GM-CSF. One-year progression free survival between two groups was compared.

RESULTS

Three months after treatment, the efficacy in experimental group was significantly better than that in control group, and objective response rate was 95.24% in experimental group, which was higher than the 71.43% in control group. Patients in experimental group had no differences in white blood cell and neutrophil, but had significantly lower carcino-embryonic antigen and neuron-specific enolase levels and higher CD3+, CD4+, and CD4+/CD8+ than those in control group and before treatment. There were no differences in the proportion of patients with adverse reactions between two groups. One-year progression free survival was significantly better in experimental group than in control group.

CONCLUSIONS

Early combination of local radiotherapy and GM-CSF has a significant efficacy for advanced NSCLC accounts for approximately 4/5 of lung cancers treated with icotinib, and it can improve patients' autoimmunity and lengthen progression free survival.

Clinicopathologic Characteristics, Treatment Outcomes, and Acquired Resistance Patterns of Atypical EGFR Mutations and HER2 Alterations in Stage IV Non-Small-Cell Lung Cancer

BACKGROUND

The clinicopathologic characteristics, acquired resistance patterns, and outcomes among patients with atypical EGFR mutations and HER2 alterations remain underexplored.

PATIENTS AND METHODS

A single-center retrospective review was conducted. Oncogenes assessed include typical EGFR (t-EGFR; exon 19 del and L858R), atypical EGFR (a-EGFR; G719X, exon 20, L861Q), HER2 (exon 19, exon 20, amplifications), gene fusions (ALK, ROS1, RET), RAS (KRAS, NRAS), and RAF (BRAF V600E). Progression-free survival (PFS), overall survival (OS), disease control rate, and objective response rate (Response Evaluation Criteria in Solid Tumors 1.1) were collected.

RESULTS

Among 570 patients, we found 55 a-EGFR mutations (13 G719X, 38 exon 20, 4 L861Q) and 31 HER2 alterations (2 exon 19 mutations, 27 exon 20 insertions, 2 amplifications). Patients with EGFR and HER2 alterations had increased lung and bone metastases relative to patients with gene fusions, RAS/RAF mutations, and no identified driver oncogenes (P < .001). Patients with EGFR exon 20 insertions had a median PFS to EGFR tyrosine kinase inhibitors (TKIs) of 5 months and an OS of 16 months-significantly worse than exon 19 del and L858R (Bonferroni correction; P < .001), but not G719X or L861Q. Relative to t-EGFR mutations, T790M and MET amplification occurred less frequently as acquired resistance mechanisms among a-EGFR samples (P < .001). Ten patients with a-EGFR mutations and HER2 alterations received single-agent immune checkpoint inhibitors (ICIs) with no radiographic responses and a median PFS of 2 months.

CONCLUSION

EGFR and HER2-mutated NSCLC have a high rate of synchronous lung and bone metastases. Patients with a-EGFR mutations have inferior responses to EGFR-directed therapies with lower rates of acquired T790M and MET amplification. Responses to ICIs are uniformly poor. Novel therapeutic approaches are needed.

Independent prognostic value of ultra-sensitive quantification of tumor pre-treatment T790M subclones in EGFR mutated non-small cell lung cancer (NSCLC) treated by first/second generation TKI, depends on variant allele frequency (VAF): Results of the French cooperative thoracic intergroup (IFCT) biomarkers France project

OBJECTIVES

T790M mutations inEGFR-mutated non-small cell lung cancer (NSCLC) account for nearly 50% of acquired resistance mechanisms to EGFR-TKIs. Earlier studies suggested that tumor T790M could also be detected in TKI-naïve EGFR-mutated NSCLC. The aim of the study is to assess the prevalence and clinical significance of quantification of tumor pre-treatment T790M subclones.

MATERIALS AND METHODS

We analyzed 366 EGFR-mutated NSCLC patients of the real-life IFCT Biomarkers France study with available pre-treatment formalin-fixed paraffin-embedded (FFPE) tumor DNA before treatment by first/second-generation EGFR-TKI. We used ultra-sensitive Droplet Digital Polymerase Chain Reaction (ddPCR) QX200 (BIO-RAD®, Hercules, CA, USA). All samples were tested in duplicate.

RESULTS

ddPCR identified T790M in 19/240 specimens (8%). T790M-positive and T790M-negative populations were not different for clinical baseline characteristics. T790M Variant Allele Frequency (VAF) was > 0.01% <0.1%, > 0.1% <1%, > 1% <10%, and >10% in five (26.3%), six (31.6%), six (31.6%), and two (10.5%) patients, respectively. T790M VAF was >0.1% in 11/13 (84%) patients with rapid (<3 months) or usual progression (3-20 months) compared to 0/3 with low progression (>20 months) (p = 0.02). In a Cox model, T790M mutation positivity was correlated with overall survival (OS) and progression-free survival (PFS) for 10% > VAF >1% (hazard ratio [HR] = 2.83, 95% confidence interval [CI] 1.13-7.07, p = 0.03; HR=3.62, 95%CI 1.43-4.92, p = 0.007, respectively) and for VAF >10% (HR = 19.14, 95%CI 4.35-84.26, p < 0.001; HR = 17.89, 95%CI 2.21-144.86, p = 0.007, respectively).

CONCLUSION

Ultra-sensitive detection of tumor T790M mutation concerned 8% of EGFR-mutated TKI-naïve NSCLC patients and has a negative prognostic value only for T790M VAF over 1%.

Detection of rare and novel EGFR mutations in NSCLC patients: Implications for treatment-decision

OBJECTIVES

Mutations in the gene that encodes epidermal growth factor receptor (EGFR) are biomarkers that predict how non-small cell lung cancer (NSCLC) patients respond to EGFR-targeted therapies collectively known as tyrosine kinase inhibitors (TKIs). Thus, EGFR genotyping provides crucial information for treatment decision. Both Sanger sequencing and real-time PCR methodologies are used for EGFR genotyping. However, methods based on real-time PCR have limitations, as they may not detect rare or novel mutations. The aim of this study was to determine the prevalence of rare mutations in the tyrosine kinase domain (exons 18-21) of the EGFR gene not targeted by the most frequently used real-time PCR approaches, i.e., the cobas® EGFR Mutation Test, and the Idylla™ EGFR Mutation Assay.

METHODS

A total of 1228 NSCLC patients were screened for mutations in exons 18-21 of the EGFR gene using Sanger sequencing.

RESULTS

We observed that 252 patients (∼20%) had at least one mutation in the EGFR gene, and 38 (∼3%) carried uncommon genetic alterations that would not be identified by the cobas® or the Idylla™ tests. We further found six new single mutations and seven previously unreported compound mutations. Clinical information and patient outcome are presented for these cases.

CONCLUSIONS

This study highlights the value of sequencing-based approaches to identify rare mutations. Our results add to the inventory of known EGFR mutations, thus contributing to improved lung cancer precision treatment.