A Novel EGFR Mutation in Exon 19 Showed Stable Disease After TKI Treatment

Genomic features of lung cancer patients in Indonesia's national cancer center

INTRODUCTION

Advances in molecular biology bring advantages to lung cancer management. Moreover, high-throughput molecular tests are currently useful for revealing genetic variations among lung cancer patients. We investigated the genomics profile of the lung cancer patients at the National Cancer Centre of Indonesia.

METHODS

A retrospective study enrolled 627 tissue biopsy samples using real time polymerase chain reaction (RT-PCR) and 80 circulating tumour DNA (ctDNA) liquid biopsy samples using next-generation sequencing (NGS) from lung cancer patients admitted to the Dharmais Cancer Hospital from January 2018 to December 2022. Data were obtained from medical records. Data statistically analysed with p < 0.05 is considered significant.

RESULT

The EGFR test results revealed by RT-PCR were wild type (51.5%), single variant (38.8%), double variant (8.3%), and triple variant (1.4%), with 18.66% L85R, 18.22% Ex19del, and 11.08% L861Q variant. Liquid biopsy ctDNA using NGS showed only 2.5% EGFR wild type, 62.5% single variant and 35% co-variant, with EGFR/TP53 and EGFR/PIK3CA as the highest.

CONCLUSION

EGFR variants are the most found in our centre. Liquid biopsy with ctDNA using NGS examination could detect broad variants and co-variants that will influence the treatment planning.

Case Report: Afatinib Sensitivity in Rare EGFR E746_L747delinsIP Mutated LUAD With Peritoneal Metastases

Patients with non-small cell lung cancer harboring the epidermal growth factor receptor (EGFR)-sensitive mutations are known to benefit significantly from EGFR tyrosine kinase inhibitors (TKIs), such as erlotinib, gefitinib, icotinib, or afatinib. However, the efficacy of EGFR-TKIs against rare mutations has not yet been well investigated. Here, we report a female patient with advanced lung adenocarcinoma (LUAD), carrying a rare mutation of EGFR Exon19 E746_L747delinsIP, who was administered first-generation EGFR-TKIs as the first-line treatment. The patient continued to progress slowly until peritoneal metastases have occurred. Subsequently, the patient was treated with anlotinib for 5 months until disease progression. Given the finding of the same EGFR rare mutation in peritoneal effusion without other EGFR-TKI resistance mutations, the patient received afatinib with a tremendous response. Our results may be of clinical relevance for patients with LUAD carrying this rare mutation, and these findings warrant further investigation.

The Lifted Veil of Uncommon EGFR Mutation p.L747P in Non-Small Cell Lung Cancer: Molecular Feature and Targeting Sensitivity to Tyrosine Kinase Inhibitors

Objectives

The uncommon p.L747P mutation in epidermal growth factor receptor (EGFR) exon 19 reveals to alter the response to tyrosine kinase inhibitors (TKIs) in patients diagnosed with advanced non-small cell lung cancer (NSCLC). However, the underlying mechanism is still not clear. This study aimed to investigate the clinical outcomes, binding affinities, and modes of action of currently available EGFR TKIs towards p.L747P mutation.

Materials and Methods

Clinical data of NSCLC patients harboring p.L747P mutation who had received different generations of EGFR TKIs were collected from medical records. Computational structure of p.L747P was constructed and in vitro cellular kinase inhibition assay and mice xenograft experiment were performed to predict and confirm the binding affinities and antitumor activities of diverse EGFR TKIs.

Results

A total of five metastatic NSCLC patients with p.L747P mutation were included in the final analysis. Patients treated with second-generation (2G) TKI afatinib achieved numerically longer progression-free survival (range 2.4-8.5 months) than that with first-generation (1G, range 1.4-5.5 months) or third-generation (3G, range 1.6-7.5 months) TKIs. None of the patients administered 1G or 3G TKIs achieved tumor response, but two-thirds of them treated with afatinib achieved partial response. Dynamics simulation predicted that 2G TKIs presented the best binding affinity to p.L747P mutation. The cellular kinase inhibition assay and mice xenograft experiment confirmed that afatinib could potently inhibit p.L747P-mutant cells and significantly reduce p.L747P-mutant tumor growth (P< 0.001), together with reduced phosphorylation of EGFR and its downstream signalings.

Conclusions

The uncommon p.L747P mutation in EGFR exon 19 resulted in a poor response to first-generation EGFR TKIs. Afatinib revealed a better clinical response and binding affinity compared with osimertinib for this specific alteration.

Patients harboring uncommon EGFR exon 19 deletion-insertion mutations respond well to first-generation EGFR inhibitors and osimeritinib upon acquisition of T790M

Background

In the existing next generation sequencing (NGS) system, epidermal growth factor receptor (EGFR) exon 19 deletion-insertion (19delins) is still interpreted into the category of EGFR exon 19 deletion (19del). However, the controversy exists whether the two mutation types have the similar responses and resistant mechanisms to first-generation EGFR tyrosine kinase inhibitor (TKI) in non-small cell lung cancer (NSCLC) patients.

Methods

We successively and retrospectively reviewed the NGS data of 3054 patients diagnosed as advanced NSCLC from November 2017 to September 2020. Finally, 41 patients with EGFR 19delins mutation and 41 patients with EGFR 19del mutation who received first-generation EGFR TKIs as first-line therapy were included in the study.

Results

A total of 17 genotypes were identified in this study, including L747_P753delinsS (10/41), L747_A750delinsP (9/41), L747_T751delinsP (6/41) and E746_S752delinsV (3/41). Under the same baseline characteristics, the population of EGFR 19delins respond well to first line EGFR TKIs as well as those of EGFR 19del, with little difference in median progression-free survival (mPFS): 10.4 months vs. 13.1 months, p = 0.1076). Interestingly, patients with L747_T751delinsP seem to have a better mPFS than others (18.7 months vs. 13.1 months, p = 0.035). After the disease progression, both EGFR 19delins and EGFR 19del had similar rates of developing EGFR T790M mutation resistance (45.8% vs. 57.8%), and those receiving osimeritinib as second-line treatment obtain the similar survival benefits (mPFS: 12.0 months vs. 12.2 months (p = 0.97).

Conclusions

This retrospective cohort study furnish the evidence that therapeutic responses and survival of untreated NSCLC population with EGFR 19delins mutation are equal to those with common EGFR 19del mutation after administration of EGFR TKIs therapy.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12885-021-08942-x.

Microsecond-timescale MD simulation of EGFR minor mutation predicts the structural flexibility of EGFR kinase core that reflects EGFR inhibitor sensitivity

Approximately 15–30% of patients with lung cancer harbor mutations in the EGFR gene. Major EGFR mutations (>90% of EGFR-mutated lung cancer) are highly sensitive to EGFR tyrosine kinase inhibitors (TKIs). Many uncommon EGFR mutations have been identified, but little is known regarding their characteristics, activation, and sensitivity to various EGFR-TKIs, including allosteric inhibitors. We encountered a case harboring an EGFR-L747P mutation, originally misdiagnosed with EGFR-del19 mutation using a routine diagnostic EGFR mutation test, which was resistant to EGFR-TKI gefitinib. Using this minor mutation and common EGFR-activating mutations, we performed the binding free energy calculations and microsecond-timescale molecular dynamic (MD) simulations, revealing that the L747P mutation considerably stabilizes the active conformation through a salt-bridge formation between K745 and E762. We further revealed why several EGFR inhibitors, including the allosteric inhibitor, were ineffective. Our computational structural analysis strategy would be beneficial for future drug development targeting the EGFR minor mutations.

A rare EGFR mutation L747P conferred therapeutic efficacy to both gefitinib and osimertinib: A case report

EGFR mutations, primarily sensitizing mutations such as exon 19 deletion and exon 21 point mutations, have been proven to act as predictive biomarkers for the response to tyrosine kinase inhibitors (TKIs). How patients harboring EGFR L747 P (a rare mutation located in exon 19) respond to EGFR-TKI is controversial. Some studies have described EGFR L747 P as providing intrinsic resistance to EGFR-TKIs, but others support this rare mutation as a sensitive mutation. Hence, we reported a patient with advanced lung adenocarcinoma harboring an EGFR L747 P who benefited from first-line treatment with gefitinib. This patient achieved stable disease (SD) and had a progression-free survival (PFS) of 18 months. After disease progression, this patient was subsequently administered osimertinib and responded, as evidenced by a significant reduction in nodular lesions. This case revealed that EGFR L747 P rendered both gefitinib and osimertinib therapeutically efficacious.

Afatinib is effective in the treatment of lung adenocarcinoma with uncommon EGFR p.L747P and p.L747S mutations

OBJECTIVES

Epidermal growth factor receptor (EGFR) tyrosine kinase inhibitors (TKIs) are used as first-line standard treatment for advanced lung adenocarcinoma with mutant EGFR. Nevertheless, few studies have demonstrated the efficacy of first- and second-generation EGFR TKIs in patients harboring the uncommon p.L747P and p.L747S mutations in exon 19 of EGFR.

MATERIALS AND METHODS

From 2005-2018, we identified patients with lung adenocarcinoma with EGFR p.L747P or p.L747S mutations using DNA and cDNA sequencing or commercial kits and recorded their clinical data. Published data pertaining to these mutations were also reviewed.

RESULTS

Twelve eligible patients were enrolled at National Taiwan University Hospital (NTUH), and ten additional patients were identified in published literature. In NTUH cohort, the direct DNA sequencing had a 60.0% (3 of 5 patients) false-negative rate, and use of commercial kits all caused misidentification of EGFR p.L747P or p.L747S. Of the 7 patients receiving EGFR TKI treatment, five stage-IV lung adenocarcinoma patients that received afatinib had a 80.0% objective response rate (ORR), while two patients administered gefitinib or erlotinib showed a 0% ORR. The median progression-free survival (PFS) rates were 11.97 and 0.92 months (P = 0.012) for afatinib and gefitinib/erlotinib, respectively. No patients (0%) acquired p.T790 M resistance after failure of afatinib (n = 3). Of 10 patients harboring EGFR p.L747P from published literature, six patients used first-generation EGFR TKIs as treatment also showed 0% ORR and 1.00 month median PFS.

CONCLUSIONS

Patients with the uncommon EGFR mutations p.L747P and p.L747S could be incorrectly classified as having wild-type EGFR or a 19DEL when using direct DNA sequencing or commercial kits. Moreover, use of afatinib may provide significantly improved PFS in patients with advanced lung adenocarcinoma with one of these two EGFR mutations.

Clinical Impact of Rare and Compound Mutations of Epidermal Growth Factor Receptor in Patients With Non-Small-Cell Lung Cancer

BACKGROUND

Standard therapy of advanced non-small-cell lung cancer harboring an activating mutation in the epidermal growth factor receptor (EGFR) gene is treatment with tyrosine kinase inhibitors (TKI). However, for rare and compound mutations of the EGFR gene, the clinical evidence of TKI therapy is still unclear.

PATIENTS AND METHODS

A total of 2906 lung cancer samples were analyzed for EGFR mutations during routine analysis between 2010 and 2017. The samples have been investigated by Sanger sequencing and since 2014 by next-generation sequencing.

RESULTS

We detected EGFR mutations in 408 specimens (14%). Among these, we found 41 samples with rare and 22 with compound mutations. In these 63 samples, 56 different rare EGFR mutations occurred. Information about the clinical outcome was available for 37. Among those with rare mutations, only one patient harboring the mutation p.G874D had disease that responded to first-generation TKI therapy. In contrast, the disease of all patients with compound mutations responded to first- or second-generation TKI therapy. Furthermore, we collected data on clinical relevance regarding TKI therapy from different databases and from an additional literature search, and only found data for 36 of the 56 detected rare mutations.

CONCLUSION

Information about the clinical outcome of patients with rare and compound EGFR mutations remains limited. At present, second- and third-generation TKIs are available, which may represent new treatment strategies for these patients. Therefore, it is becoming increasingly important to maintain databases concerning rare EGFR mutations.

Management of EGFR mutated nonsmall cell lung carcinoma patients

Tyrosine kinase inhibitors (TKIs) targeting the epidermal growth factor receptor (EGFR) are common in the therapeutic armentarium of lung cancer today. Initially tested in an unselected population, they have been of limited usefulness until the identification EGFR gene mutations. Activating mutations generate conformational changes that result in a shift toward an active state of the catalytic domain and are associated with sensitivity to first generation EGFR TKI. Other mutations have been associated with resistance to these drugs, but for rare mutations there is limited data concerning their role in predicting response to EGFR TKI. To date, four molecules have been approved for the treatment of EGFR mutated lung cancer. Gefitinib and/or erlotinib are available in almost all countries. Afatinib has been approved by the US Food and Drug Administration and by the European Medicines Agency, and icotinib has been approved only in China. Other, more active, third generation agents with a higher binding affinity for the receptor, or that are directed against specific mutations, are under development. EGFR TKIs have a favourable impact on progression-free survival when given as first line treatment in mutated patients, but may also have a moderate effect as a salvage therapy and in maintenance in an unselected population.

Concomitant ALK translocation and EGFR mutation in lung cancer: a comparison of direct sequencing and sensitive assays and the impact on responsiveness to tyrosine kinase inhibitor

BACKGROUND

Epidermal growth factor receptor (EGFR) mutation and anaplastic lymphoma kinase (ALK) translocation are considered mutually exclusive in nonsmall-cell lung cancer (NSCLC). However, sporadic cases having concomitant EGFR and ALK alterations have been reported. The present study aimed to assess the prevalence of NSCLCs with concomitant EGFR and ALK alterations using mutation detection methods with different sensitivity and to propose an effective diagnostic and therapeutic strategy.

PATIENTS AND METHODS

A total of 1458 cases of lung cancer were screened for EGFR and ALK alterations by direct sequencing and flourescence in situ hybridization (FISH), respectively. For the 91 patients identified as having an ALK translocation, peptide nucleic acid (PNA)-clamping real-time PCR, targeted next-generation sequencing (NGS), and mutant-enriched NGS assays were carried out to detect EGFR mutation.

RESULTS

EGFR mutations and ALK translocations were observed in 42.4% (612/1445) and 6.3% (91/1445) of NSCLCs by direct sequencing and FISH, respectively. Concomitant EGFR and ALK alterations were detected in four cases, which accounted for 4.4% (4/91) of ALK-translocated NSCLCs. Additional analyses for EGFR using PNA real-time PCR and ultra-deep sequencing by NGS, mutant-enriched NGS increased the detection rate of concomitant EGFR and ALK alterations to 8.8% (8/91), 12.1% (11/91), and 15.4% (14/91) of ALK-translocated NSCLCs, respectively. Of the 14 patients, 3 who were treated with gefitinib showed poor response to gefitinib with stable disease in one and progressive disease in two patients. However, eight patients who received ALK inhibitor (crizotinib or ceritinib) showed good response, with response rate of 87.5% (7/8 with partial response) and durable progression-free survival.

CONCLUSIONS

A portion of NSCLC patients have concomitant EGFR and ALK alterations and the frequency of co-alteration detection increases when sensitive detection methods for EGFR mutation are applied. ALK inhibitors appear to be effective for patients with co-alterations.

A cautionary lesson on the use of targeted methods for EGFR mutation analysis: a case report

Epidermal growth factor receptor (EGFR) mutation analysis is recommended for lung cancer patients prior to the prescription of first-line EGFR tyrosine kinase inhibitors in order to predict response to treatment. There are many methods available to identify mutations in the EGFR gene; a large number of clinical laboratories use the therascreen EGFR RGQ PCR kit (Qiagen). We report a case where this kit detected an exon 19 deletion, predicting sensitivity to tyrosine kinase inhibitors (TKIs), which on further analysis was found to be a 2 bp indel (c.2239_2240delinsCC, p.(Leu747Pro)). Two of four published cases with this mutation were found to be associated with resistance to EGFR TKI. The sample was also tested using two other commercial kits, one of which indicated a deletion. This is a rare mutation making the erroneous detection of a deletion unlikely; however, it is important that clinical laboratories are aware of the potential failings of two commercial kits for EGFR mutation analysis.

Efficiency of the Therascreen® RGQ PCR kit for the detection of EGFR mutations in non-small cell lung carcinomas

BACKGROUND

Activating mutations of the EGFR gene in lung carcinoma are associated with response to tyrosine kinase inhibitors. Therefore, a rapid, sensitive assay for mutation detection using routine pathological specimens is mandatory in clinical practice.

METHODS

We have compared our in-house procedure to the Therascreen® EGFR RGQ PCR kit (Qiagen). This assay, based on allele-specific amplification, is approved in the United States, in Europe, Japan and China.

RESULTS

We first selected a series of 209 that were representative of our routine practice during the last 2years. Using our assays, EGFR mutations were detected in 36 (17.4%) of these patients (18 p.L858R mutations and 18 exon 19 deletions). All these alterations were also detected using the Therascreen® kit. In addition, this kit allowed us to detect 7 additional alterations: one exon 19 alteration (c.2239_2240TT>CC, p.L747P), 3 p.G719X mutations and 3 p.S768L mutations. In the second part of our study, we selected 81 samples that were identified as deleted for exon 19 using our assay. Eighteen different deletions were described following sequencing. All these samples were tested positive with the Therascreen® kit.

CONCLUSION

The Therascreen® EGFR RGQ kit was found to be very powerful (sensitivity 100%; specificity 100%) for the detection of the most frequent EGFR alterations that are clearly associated with response to tyrosine kinase inhibitors.