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

From Rarity to Reality: Osimertinib's Promising Horizon in Treating Uncommon EGFR Mutations in Non-Small Cell Lung Cancer

In the realm of advanced non-small cell lung cancer (NSCLC) harboring epidermal growth factor receptor (EGFR) therapy with tyrosine kinase inhibitors (TKI), addressing optimal treatment for uncommon EGFR mutations like G719X in exon 18, S768I in exon 20, and L861Q in exon 21 remains a pivotal yet challenging frontier. Contrary to the well-established efficacy of EGFR-TKIs in common EGFR mutations, these uncommon alterations pose unmet medical needs due to a lack of comprehensive evidence. While afatinib, a second-generation EGFR-TKI, has received FDA approval for patients with these uncommon EGFR mutations, the approval was based on a post-hoc analysis of randomized clinical trials. Recent developments include multiple clinical trials investigating the efficacy of both second- and third-generation EGFR-TKIs in patients with uncommon EGFR mutations. A noteworthy example is a prospective phase II trial of osimertinib including the landmark UNICORN study, which has shown promising results in treating uncommon EGFR mutations. Despite various reports on the efficacy of afatinib and osimertinib in treating uncommon EGFR mutations, the appropriate use of these TKIs remains unclear. This review aims to consolidate the findings from the latest clinical trials focused on uncommon EGFR mutations, outlining variations in the therapeutic efficacy of these TKIs based on the specific genetic mutation. By synthesizing these findings, we aim to guide oncologists toward more informed decisions in employing TKIs for NSCLC with uncommon EGFR mutations other than exon 20 insertion. Additionally, we explore potential treatment strategies tailored to these patient populations to address the challenges posed by these mutations.

Identification of potential inhibitors for drug-resistant EGFR mutations in non-small cell lung cancer using whole exome sequencing data

Epidermal growth factor receptor (EGFR) gene mutations are prevalent in about 50% of lung adenocarcinoma patients. Highly effective tyrosine kinase inhibitors (TKIs) targeting the EGFR protein have revolutionized treatment for the prevalent and aggressive lung malignancy. However, the emergence of new EGFR mutations and the rapid development of additional drug resistance mechanisms pose substantial challenge to the effective treatment of NSCLC. To investigate the underlying causes of drug resistance, we utilized next-generation sequencing data to analyse the genetic alterations in different tumor genomic states under the pressure of drug selection. This study involved a comprehensive analysis of whole exome sequencing data (WES) from NSCLC patients before and after treatment with afatinib and osimertinib with a goal to identify drug resistance mutations from the post-treatment WES data. We identified five EGFR single-point mutations (L718A, G724E, G724K, K745L, V851D) and one double mutation (T790M/L858R) associated with drug resistance. Through molecular docking, we observed that mutations, G724E, K745L, V851D, and T790M/L858R, have negatively affected the binding affinity with the FDA-approved drugs. Further, molecular dynamic simulations revealed the detrimental impact of these mutations on the binding efficacy. Finally, we conducted virtual screening against structurally similar compounds to afatinib and osimertinib and identified three compounds (CID 71496460, 73292362, and 73292545) that showed the potential to selectively inhibit EGFR despite the drug-resistance mutations. The WES-based study provides additional insight to understand the drug resistance mechanisms driven by tumor mutations and helps develop potential lead compounds to inhibit EGFR in the presence of drug resistance mutations.

Clinicopathological and prognostic implications of EGFR mutations subtypes in Moroccan non-small cell lung cancer patients: A first report

BACKGROUND

Non-small cell lung cancer (NSCLC) remains a significant global health concern, with EGFR mutations playing a pivotal role in guiding treatment decisions. This prospective study investigated the prevalence and clinical implications of EGFR mutations in Moroccan NSCLC patients.

METHODS

A cohort of 302 NSCLC patients was analyzed for EGFR mutations using multiple techniques. Demographic, clinical, and pathological characteristics were assessed, and overall survival (OS) outcomes were compared among different EGFR mutation subtypes.

RESULTS

EGFR mutations were present in 23.5% of patients, with common mutations (81.69%) dominating. Common mutations showed strong associations with female gender and non-smoking status, while rare mutations were associated with a positive smoking history. Patients with EGFR mutations receiving tyrosine kinase inhibitors (TKIs) had significantly improved OS compared to wild-type EGFR patients. Notably, patients with common EGFR mutations had the highest OS, while those with rare mutations had a shorter survival period, albeit not statistically significant.

CONCLUSION

This study highlights the relevance of EGFR mutation status in NSCLC patients, particularly in therapeutic decision-making. The association between smoking history and rare mutations suggests the need for tailored approaches. The survival advantage for patients with common EGFR mutations underscores the significance of personalized treatment strategies.

Emerging paradigms and recent progress in targeting ErbB in cancers

The epidermal growth factor receptor (EGFR) family is a class of transmembrane proteins, highly regarded as anticancer targets due to their pivotal role in various malignancies. Standard cancer treatments targeting the ErbB receptors include tyrosine kinase inhibitors (TKIs) and monoclonal antibodies (mAbs). Despite their substantial survival benefits, the achievement of curative outcomes is hindered by acquired resistance. Recent advancements in anti-ErbB approaches, such as inhibitory peptides, nanobodies, targeted-protein degradation strategies, and bispecific antibodies (BsAbs), aim to overcome such resistance. More recently, emerging insights into the cell surface interactome of the ErbB family open new avenues for modulating ErbB signaling by targeting specific domains of ErbB partners. Here, we review recent progress in ErbB targeting and elucidate emerging paradigms that underscore the significance of EGF domain-containing proteins (EDCPs) as new ErbB-targeting pathways.

Radiomics of metastatic brain tumor as a predictive image biomarker of progression-free survival in patients with non-small-cell lung cancer with brain metastasis receiving tyrosine kinase inhibitors

BACKGROUND AND OBJECTIVE

Epidermal growth factor receptor (EGFR)-targeted tyrosine kinase inhibitors (TKIs) are the first-line therapy for EGFR-mutant non-small-cell lung cancer (NSCLC). Early prediction of treatment failure in patients with brain metastases treated with EGFR-TKIs may help in making decisions for systemic drug therapy or local brain tumor control. This study examined the predictive power of the radiomics of both brain metastasis tumors and primary lung tumors. We propose a deep learning based CoxCC model based on quantitative brain magnetic resonance imaging (MRI), a prognostic index and clinical data; the model can be used to predict progression-free survival (PFS) after EGFR-TKI therapy in advanced EGFR-mutant NSCLC.

METHODS

This retrospective single-center study included 271 patients receiving first-line EGFR-TKI targeted therapy in 2018-2019. Among them, 72 patients who had brain metastases before receiving first-line EGFR-TKI treatment. Three radiomic features were extracted from pretreatment brain MRI images. A CoxCC model for the progression risk stratification of EGFR-TKI treatment was proposed on the basis of MRI radiomics, clinical features, and a prognostic index. We performed time-dependent PFS predictions to evaluate the performance of the CoxCC model.

RESULTS

The CoxCC model based on a prognostic index, clinical features, and radiomic features of brain metastasis exhibited higher performance than clinical features combined with indexes previously proposed for determining the prognosis of brain metastasis, including recursive partitioning analysis, diagnostic-specific graded prognostic assessment, graded prognostic assessment for lung cancer using molecular markers (lung-molGPA), and modified lung-molGPA, with c-index values of 0.75, 0.67, 0.66, 0.65, and 0.65, respectively. The model achieved areas under the curve of 0.88, 0.73, 0.92, and 0.90 for predicting PFS at 3, 6, 9 and 12 months, respectively. PFS significantly differed between the high- and low-risk groups (p < 0.001).

CONCLUSIONS

For patients with advanced-stage NSCLC with brain metastasis, MRI radiomics of brain metastases may predict PFS. The CoxCC model integrating brain metastasis radiomics, clinical features, and a prognostic index provided reliable multi-time-point PFS predictions for patients with advanced NSCLC and brain metastases receiving EGFR-TKI treatment.

Hope and Challenges: Immunotherapy in EGFR-Mutant NSCLC Patients

EGFR tyrosine kinase inhibitors (TKIs) are the preferred initial treatment for non-small cell lung cancer (NSCLC) patients harboring sensitive EGFR mutations. Sadly, remission is transient, and no approved effective treatment options are available for EGFR-TKI-advanced EGFR-mutant NSCLCs. Although immunotherapy with immune checkpoint inhibitors (ICIs) induces sustained cancer remission in a subset of NSCLCs, ICI therapy exhibits limited activity in most EGFR-mutant NSCLCs. Mechanistically, the strong oncogenic EGFR signaling in EGFR-mutant NSCLCs contributes to a non-inflamed tumor immune microenvironment (TIME), characterized by a limited number of CD8+ T cell infiltration, a high number of regulatory CD4+ T cells, and an increased number of inactivated infiltrated T cells. Additionally, EGFR-mutant NSCLC patients are generally non-smokers with low levels of PD-L1 expression and tumor mutation burden. Promisingly, a small population of EGFR-mutant NSCLCs still durably respond to ICI therapy. The hope of ICI therapy from pre-clinical studies and clinical trials is reviewed in EGFR-mutant NSCLCs. The challenges of application ICI therapy in EGFR-mutant NSCLCs are also reviewed.

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.

Chemotherapy outcomes in EGFR-TKI resistant patients with common and uncommon EGFR mutation: An exploratory retrospective cohort study

BACKGROUND

Some prospective studies have shown that second-generation tyrosine kinase inhibitors (TKIs) provide better control in patients with non-small cell lung cancer (NSCLC) with uncommon epidermal growth factor receptor (EGFR) mutations. However, studies comparing second-line chemotherapy efficacy between NSCLC patients with common and uncommon EGFR mutations remain rare. This retrospective study compared treatment outcomes in these patients.

METHODS

Patients with EGFR-mutated advanced-stage NSCLC who received first-line EGFR-TKIs in a tertiary referral center were retrospectively reviewed between January 2010 and August 2022. Patients with a negative T790M test at disease progression who received second-line chemotherapy were enrolled. We compared progression-free (PFS) and overall (OS) survival between advanced NSCLC patients with common and uncommon EGFR mutations using Kaplan-Meier and log-rank tests.

RESULTS

In total, 209 (54.8%) patients had a negative T790M mutation test and received second-line chemotherapy, of which 192 (91.8%) had a common EGFR mutation (exon 19 deletion or exon 21 L858R substitution), and 17 (8.2%) had an uncommon EGFR mutation. Patients with common EGFR mutations had significantly longer PFS than those with uncommon EGFR mutations (4.57 vs. 2.57 months, p = 0.031). A Cox proportional hazard regression analysis controlling for potential confounding factors indicated that an uncommon EGFR mutation was an independent prognostic factor for PFS.

CONCLUSION

This study suggests that patients with uncommon EGFR mutations have poorer chemotherapy responses and shorter survival than those with common EGFR mutations. The development of new treatment strategies for these patients remains an unmet need.

Afatinib for the Treatment of NSCLC with Uncommon EGFR Mutations: A Narrative Review

Afatinib, the world's first irreversible ErbB family (containing four different cancer cell epidermal growth factor receptors, including EGFR, HER2, ErbB3, and ErbB4) inhibitor, is a second-generation oral epidermal growth factor receptor tyrosine kinase inhibitor (EGFR-TKI). It can be used as a first-line treatment for locally advanced or metastatic non-small-cell lung cancer (NSCLC) with an EGFR-sensitive mutation or for patients with locally advanced or metastatic squamous lung cancer whose disease progresses during or after platinum-containing chemotherapy. Currently, with the use of third-generation EGFR-TKIs, afatinib is no longer clinically indicated as the first choice for patients with NSCLC who have EGFR-sensitive mutations. However, afatinib showed a considerable inhibitory effect in NSCLC patients with uncommon EGFR mutations (G719X, S768I, and L861Q) according to a combined post hoc analysis of the LUX-Lung2/3/6 trials. With the development of genetic testing technology, the detection rate of uncommon EGFR mutations is increasing. The aim of this paper is to describe in detail the sensitivity of rare EGFR mutations to afatinib and to provide information and a reference for those suffering from advanced NSCLC who have uncommon EGFR mutations.

Adaptive therapy to circumvent drug resistance to tyrosine kinase inhibitors in cancer: is it clinically relevant?

INTRODUCTION

Cancer is highly adaptable and is constantly evolving against current targeted therapies such as tyrosine kinase inhibitors. Despite advances in recent decades, the emergence of drug resistance to tyrosine kinase inhibitors constantly hampers therapeutic efficacy of cancer treatment. Continuous therapy versus intermittent clinical regimen has been a debate in drug administration of cancer patients. An ecologically-inspired shift in cancer treatment known as 'adaptive therapy' intends to improve the drug administration of drugs to cancer patients that can delay emergence of drug resistance.

AREAS COVERED

We discuss improved understanding of the concept of drug resistance, the basis of continuous therapy, intermittent clinical regimens, and adaptive therapy will be reviewed. In addition, we discuss how adaptive therapy provides guidance for future cancer treatment.

EXPERT OPINION

The current understanding of drug resistance in cancer leads to poor prognosis and limited treatment options in patients. Fighting drug resistance mutants is constantly followed by new forms of resistance. In most reported cases, continuous therapy leads to drug resistance and an intermittent clinical regimen vaguely delays it. However, adaptive therapy, conceptually, exploits multiple parameters that can suppress the growth of drug resistance and provides safe treatment for cancer patients in the future.

Immunotherapy for EGFR-mutant advanced non-small-cell lung cancer: Current status, possible mechanisms and application prospects

Immune checkpoint inhibitors (ICIs) are effective against advanced and even perioperative non-small-cell lung cancer (NSCLC) and result in durable clinical benefit, regardless of programmed death ligand-1 (PD-L1) expression status in cancer. Existing clinical evidence shows that the effect of immunotherapy in patients with EGFR-mutant NSCLC after the development of tyrosine kinase inhibitor (TKI) resistance is not satisfactory. However, compared with monotherapy, ICIs combined with chemotherapy can improve the efficacy. Encouragingly, compared with that of patients with sensitive mutations, the progression-free survival of patients with rare mutations who were treated with ICIs was increased. Adequately maximizing the efficacy of ICIs in EGFR-mutant NSCLC patients is worth exploring. In this review, we described preclinical and clinical studies of ICIs or combined therapy for EGFR-mutant NSCLC. We further focused on EGFR mutations and the cancer immune response, with particular attention given to the role of EGFR activation in the cancer-immunity cycle. The mechanisms for the natural resistance to ICIs were explored to identify corresponding countermeasures that made more EGFR-mutant NSCLC patients benefit from ICIs.

Dacomitinib for Advanced Non-small Cell Lung Cancer Patients Harboring Major Uncommon EGFR Alterations: A Dual-Center, Single-Arm, Ambispective Cohort Study in China

Objective: Dacomitinib has been approved for non-small-cell lung cancer (NSCLC) patients harboring classical epidermal growth factor receptor (EGFR) mutations; however, clinical evidence of its activity on major uncommon EGFR mutations is currently limited.

Materials and methods: This was a dual-center, single-arm, ambispective cohort study in China. Patients with histologically confirmed metastatic or recurrent NSCLC harboring major uncommon EGFR mutations were eligible for the study. The objective response rate and disease control rate were determined by RECIST 1.1 every 1–2 months. Adverse events were assessed by CTCAE 5.0.

Results: In total, 32 NSCLC patients were enrolled between July 2020 and January 2022, and 18 (56.3%) patients received dacomitinib as first-line therapy. Median age was 64 years, and 20 (62.5%) were female. The mutations identified were G719X (n = 24; 75%), followed by L861X (n = 10; 31.3%), and S768I (n = 8; 25%). In the first-line setting, 72.2% of patients (13/18) had a confirmed partial response and 100% (18/18) had disease control, and the median progression-free survival (PFS) and overall survival (OS) were unreached. In the whole cohort, 56.3% of patients (18/32) had a confirmed partial response and 90.6% (29/32) had disease control, and the median PFS was 10.3 months (95% confidence interval, 6.1–14.5) and the median OS was 36.5 months. Except for one case not available for brain re-evaluation, control of the intracranial metastases was observed in 13 patients (13/14, 92.9%). No grade 4–5 adverse events (AEs) occurred, but all patients had grade 1–2 AEs, and 12.5% (4/32) patients required a dosage reduction due to intolerable AEs.

Conclusions: Dacomitinib demonstrated favorable activity with manageable toxicity in patients with NSCLC harboring major uncommon EGFR mutations.

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.

Prevalence of Epidermal Growth Factor Receptor Exon 20 Insertion Mutations in Non-small-Cell Lung Cancer in Europe: A Pragmatic Literature Review and Meta-analysis

Background

Information on the epidemiology of uncommon EGFR mutations including exon 20 insertions amongst non-small-cell lung cancer (NSCLC) is lacking.

Objective

The objective of this pragmatic literature review (PLR) and meta-analysis was to generate robust prevalence and incidence estimates based on ranges of exon 20 insertion mutations reported in the literature.

Materials and methods

Searches of MEDLINE, Embase, congresses and reference lists for articles published from 2013 in key European countries of interest (Belgium, France, Germany, Italy, The Netherlands, Spain, Sweden, Switzerland, United Kingdom) were performed. Articles were reviewed against pre-specified criteria and their quality was appraised using a published checklist. Prevalence estimates were synthesised by random-effects meta-analyses.

Results

Eighty unique studies of moderate-to-high quality were included in the PLR. The meta-analysed prevalence for EGFR mutations was 12.5% (95% confidence interval [CI]: 11.0, 14.1) in any stage NSCLC and 14.8% (12.8, 17.1) in advanced/metastatic NSCLC. The prevalence of exon 20 insertions was 0.7% (0.4, 1.1) in any stage NSCLC and 6.1% (4.0, 9.4) in any stage EGFR-positive NSCLC. Mutation status was primarily measured using direct sequencing or a combination of methods. One study reporting exon 20 insertions in advanced/metastatic disease was identified, which reported a prevalence of 0.5% in overall NSCLC and 4.0% in EGFR-positive NSCLC.

Conclusions

EGFR exon 20 insertion mutations are rare in NSCLC. There is a high unmet need in patients with exon 20 insertions, including effective therapies. Prospective cohort studies are needed to better clinically characterise these patients.

Supplementary Information

The online version contains supplementary material available at 10.1007/s11523-022-00868-z.

Afatinib and osimertinib in lung adenocarcinoma harbored EGFR T751_I759delinsS mutation: A case report

Tyrosine kinase inhibitors (TKIs) of epidermal growth factor receptor (EGFR) are the standard treatment for lung cancer patients with activating EGFR mutation. The traditional direct polymerase chain reaction (PCR) has lower sensitivity in the detection of EGFR mutations in patient tissue samples. Whilst PCR amplification kits increase the sensitivity in detecting some types of EGFR mutations, not many types of rare mutations are found. Here, we report a patient who had lung adenocarcinoma harboring EGFR T751_I759delinsS mutation and had good response to afatinib initially and osimertinib after developing resistance to afatinib. This rare EGFR mutation was not detected by Scorpion and ARMS method but was found using the next‐generation sequencing method. There are less prospective trials in the treatment of lung adenocarcinoma with very rare EGFR mutations. Our case report could therefore provide clinical experience to the clinicians in the management of their patients.

Immunotherapy in Treating EGFR-Mutant Lung Cancer: Current Challenges and New Strategies

Lung cancer is the leading cause of cancer-related deaths worldwide. Immune checkpoint inhibitors, including monoclonal antibodies against programmed death-1 (PD-1) and programmed death ligand-1 (PD-L1), have dramatically improved the survival and quality of life of a subset of non-small cell lung cancer (NSCLC) patients. Multiple predictive biomarkers have been proposed to select the patients who may benefit from the immune checkpoint inhibitors. EGFR-mutant NSCLC is the most prevalent molecular subtype in Asian lung cancer patients. However, patients with EGFR-mutant NSCLC show poor response to anti-PD-1/PD-L1 treatment. While small-molecule EGFR tyrosine kinase inhibitors (TKIs) are the preferred initial treatment for EGFR-mutant NSCLC, acquired drug resistance is severely limiting the long-term efficacy. However, there is currently no further effective treatment option for TKIs-refractory EGFR-mutant NSCLC patients. The reasons mediating the poor response of EGFR-mutated NSCLC patients to immunotherapy are not clear. Initial investigations revealed that EGFR-mutated NSCLC has lower PD-L1 expression and a low tumor mutational burden, thus leading to weak immunogenicity. Moreover, the use of PD-1/PD-L1 blockade prior to or concurrent with osimertinib has been reported to increase the risk of pulmonary toxicity. Furthermore, emerging evidence shows that PD-1/PD-L1 blockade in NSCLC patients can lead to hyperprogressive disease associated with dismal prognosis. However, it is difficult to predict the treatment toxicity. New biomarkers are urgently needed to predict response and toxicity associated with the use of PD-1/PD-L1 immunotherapy in EGFR-mutated NSCLC. Recently, promising data have emerged to suggest the potentiation of PD-1/PD-L1 blockade therapy by anti-angiogenic agents and a few other novel therapeutic agents. This article reviews the current investigations about the poor response of EGFR-mutated NSCLC to anti-PD-1/PD-L1 therapy, and discusses the new strategies that may be adopted in the future.

Successful treatment of triple EGFR mutation T785A/L861Q/H297_E298 with afatinib

Patients with non‐small cell lung cancer (NSCLC) and uncommon epidermal growth factor receptor (EGFR) mutation are characterized by high heterogeneity, and globally considered to have a worse prognosis than patients with the two common mutations; exon 19 deletion, and exon 21 L858R. Nevertheless, some uncommon mutations do confer sensitivity to tyrosine kinase inhibitors (TKIs) which is comparable with common mutations. In particular, some compound EGFR mutations seem to be characterized by a favorable prognosis. Unfortunately, the rarity of complex EGFR mutations results in difficult clinical decision‐making. Herein, to the best of our knowledge, we report the first case of an NSCLC patient with an EGFR triple mutation containing T785A/L861Q/H297_E298 who was successfully treated with afatinib.