Uncommon EGFR mutations in a cohort of Chinese NSCLC patients and outcomes of first-line EGFR-TKIs and platinum-based chemotherapy

Efficacy and safety outcomes of emerging EGFR‑TKIs for patients with non‑small cell lung cancer with EGFR exon 20 insertion mutations: A systematic review and meta‑analysis

Lung cancer remains a leading cause of mortality worldwide, with non-small cell lung cancer (NSCLC) accounting for ~85% of all lung cancer cases. Epidermal growth factor receptor (EGFR) exon 20 insertion mutant NSCLC is rare and associated with poor outcomes. Several novel generations (third-generation) of EGFR-tyrosine kinase inhibitors (TKIs) have been developed for the treatment of NSCLC and have shown antitumour potential. Therefore, the present study reviewed their efficacy and safety outcomes for this condition. A thorough literature searching was performed using the Cochrane Library, Web of Science, PubMed and Embase databases. Clinical trials published in English and reporting overall response rate (ORR), disease control rate (DCR), progression-free survival (PFS), overall survival (OS) and treatment relevant adverse events (TRAEs) of grade ≥3 were included for further analysis. A total of 13 studies were included. All included studies reported ORRs with a pooled ORR of 0.486 [95% confidence interval (CI), 0.369-0.602]. Subgroup analysis revealed the following ORRs: 0.731 (95% CI, 0.560-0.901; I2=0%) for YK-029A; 0.608 (95% CI, 0.511-0.705; I2=0%) for sunvozertinib; 0.602 (95% CI, 0.440-0.764; I2=80.2%) for furmonertinib; 0.602 (95% CI, 0.486-0.718; I2=84.5%) for befotertinib; 0.566 (95% CI, 0.236-0.896; I2=96.3%) for amivantamab; 0.444 (95% CI, 0.215-0.674; I2=0%) for BEBT-109; and 0.256 (95% CI, 0.178-0.334; I2=75.0%) for poziotinib. The pooled DCR, median PFS and median OS were 0.843 (95% CI, 0.740-0.946), 10.11 months (95% CI, 9.58-10.64 months; I2=78.8%; P<0.001) and 23.00 months (95% CI, 20.30-25.69 months; I2=44.8; P=0.178), respectively. The pooled incidence of TRAEs of grade ≥3 was 0.458 (95% CI, 0.336-0.580; I2=96.9%; P<0.001), with the incidence of the three most reported TRAEs (diarrhoea, thrombocytopenia and anaemia) demonstrated to be 0.112 (95% CI, 0.060-0.164), 0.065 (95% CI, -0.012-0.141) and 0.040 (95% CI, 0.005-0.076), respectively. In conclusion, the emerging EGFR-TKIs for NSCLC with EGFR exon 20 insertion have a promising treatment outcome with a manageable safety profile. However, further analysis is needed when more clinical data are released.

Unraveling Survival Determinants in Patients with Advanced Non-Small-Cell Lung Cancer with EGFR Exon 20 Insertions

BACKGROUND

Lung cancer is the leading cause of cancer-related death in Taiwan. It is often associated with mutations in the epidermal growth factor receptor (EGFR) gene, with common mutations accounting for approximately 85% of all EGFR-related cases. However, the remaining 15% are caused by uncommon mutations in EGFR, mainly insertions in exon 20 (about 4%). The response to EGFR tyrosine kinase inhibitors (TKIs) can vary markedly with exon 20 insertions. However, few prior large-scale studies have examined patients with these EGFR mutations.

METHODS

This study combines the databases of several large hospitals in Taiwan to analyze the effects and clinical significance of rare EGFR mutations on responses to EGFR-TKIs, considering the changes in medication.

RESULTS

This study enrolled 38 patients with non-small-cell lung cancer and EGFR exon 20 insertions. It assessed the correlations of various predictors with progression-free survival (PFS) and overall survival (OS). It showed that among those with EGFR exon 20 insertions, the median PFS was 5.15 months, and OS reached 13 months. The median PFS was 5.4 months for afatinib, 5.7 months for chemotherapy, and 4.3 months for first-generation EGFR-TKIs.

CONCLUSIONS

EGFR-TKIs may be considered as an alternative treatment option for patients with EGFR exon 20 insertions in cases where the currently recommended therapies, such as chemotherapy with or without amivantamab, are either unavailable or intolerable. The potential use of afatinib for specific patients in this context depends on the precise characteristics of their mutation and remains to be determined.

[Advances in Diagnosis and Targeted Therapy of G719X/L861Q/S768I Mutant Non-small Cell Lung Cancer]

Lung cancer accounts for the highest proportion of cancer deaths in the world and poses a great threat to human health. About 30% to 40% of non-small cell lung cancer (NSCLC) is caused by point mutations, exon insertion and exon deletion of the epidermal growth factor receptor (EGFR). In addition to the common exon 19 deletion mutation and exon 21 L858R mutation, exon 18 G719X mutation, exon 21 L861Q mutation and exon 20 S768I mutation are the most important rare mutations. At present, the diagnostic methods for major rare mutations are mainly next-generation sequencing (NGS), digital polymerase chain reaction (dPCR), droplet digital PCR (ddPCR), etc. Regarding the targeted therapy of G719X/L861Q/S768I mutant NSCLC, the first generation EGFR-tyrosine kinase inhibitors (TKIs) have poor efficacy, while the second and third generation EGFR-TKIs have similar efficacy. The novel third generation EGFR-TKIs and combination therapy show a good therapeutic prospect. This article summarized the progress in the diagnosis and targeted therapy of G719X/L861Q/S768I mutant NSCLC, so as to provide reference for subsequent clinical drug use and research.
.

Unveiling the Landscape of Uncommon EGFR Mutations in NSCLC-A Systematic Review

Uncommon EGFR mutations represent a rare subgroup of NSCLC. Data on the efficacy of different generations of tyrosine kinase inhibitors (TKIs) in these rare mutations are scattered and limited to mostly retrospective small cohorts because these patients were usually excluded from clinical trials. This was a systematic review on the efficacy of TKIs in patients harboring uncommon EGFR mutations, defined as mutations other than exon 20 insertions mutations or T790M. Response rates (RRs) for different generations of TKIs were determined for individual uncommon mutations, compound mutations, and according to classical-like and P-loop alpha helix compressing mutations classes. This study was conducted in accordance with the 2009 Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. A total of 1836 patients from 38 studies were included in the final analysis. Most available data (92.6%) were from patients treated with first- or second-generation TKIs. G719X, S768I, E709X, L747X, and E709-T710delinsD showed RRs ranging from 47.8% to 72.3% to second-generation TKIs, generally higher than for first- or third-generation TKIs. L861Q mutation exhibited 75% (95% confidence interval [CI]: 56.6%-88.5%) RRs to third-generation TKIs. Compound mutations with G719X, E709X, or S768I consistently showed RRs above 50% to second- and third-generation TKIs, although fewer data were available for third generations. For classical-like mutations, RRs were 35.4% (95% CI: 27.2%-44.2%), 51.9% (95% CI: 44.4%-59.3%), and 67.9% (95% CI: 47.6%-84.1%) to first-, second-, and third-generation TKIs, whereas for P-loop alpha helix compressing mutations classes mutations, RRs were 37.2% (95% CI: 32.4%-42.1%), 59.6% (95% CI: 54.8%-64.3%), and 46.3% (95% CI: 32.6%-60.4%), respectively. This systematic review supports the use of second-generation TKI afatinib for G719X, S768I, E709X, and L747X mutations and for compound uncommon mutations. For other uncommon mutations such as L861Q, third-generation TKI, such as osimertinib, could also be considered, given its activity and toxicity profile.

Current management of uncommon EGFR mutations in non-small cell lung cancer

Epidermal growth factor receptor (EGFR) mutations are frequently implicated in non-small cell lung cancer (NSCLC). Though these typically involve exon 19 in-frame deletions or L858R mutations in exon 21, uncommon EGFR mutations comprise 10-15 % of all EGFR mutations. These most frequently include G719X mutations in exon 18, L861Q mutations in exon 21, S768I mutations in exon 20, and in-frame insertions and/or duplications in exon 20. It is crucial to understand these distinct variants and their specific responses to active treatment options to optimize care. In this review, we discuss these uncommon mutations in depth and dissect the current literature regarding their treatment outcomes and subsequent evidence-based management guidelines.

Cerebrospinal fluid ctDNA testing shows an advantage over plasma ctDNA testing in advanced non-small cell lung cancer patients with brain metastases

Background

Brain metastases (BM), including brain parenchyma metastases (BPM) and leptomeningeal metastases (LM), are devastating metastatic complications in advanced cancer patients. Next-generation sequencing (NGS) is emerging as a new promising tool for profiling cancer mutation, which could facilitate the diagnosis of cancer. This retrospective study aimed to investigate the molecular genetic characteristics of non-small cell lung cancer (NSCLC) patients with BPM and LM using NGS.

Methods

Cerebrospinal fluid (CSF) samples and paired plasma samples were collected from 37 patients of NSCLC-BM. We profiled genetic mutation characteristics using NGS from NSCLC-BM by comparing CSF circulating tumour DNA (ctDNA) with plasma ctDNA and primary tumour tissues.

Results

Among the 37 patients with NSCLC-BM, 28 patients had LM with or without BPM, while 9 patients only had BPM. Driver and drug-resistant mutations in primary tumours with LM included: EGFR L858R (10, 35.7%), EGFR 19del (6, 21.4%), EGFR L858R+MET (1, 3.6%), EGFR L858R+S768I (1, 3.6%), ALK (2, 7.1%), ROS1 (1, 3.6%), negative (5, 17.9%), and unknown (2, 7.1%). In patients with NSCLC-LM, the detection rate and abundance of ctDNA in the CSF were significantly higher than those in paired plasma. The main driver mutations of NSCLC-LM remained highly consistent with those of the primary tumours, along with other unique mutations. Circulating tumour DNA was negative in the CSF samples of BPM patients. Patients with BMP had a higher ratio of EGFR 19del than L858R mutation (55.6% vs 11.1.%), whereas NSCLC patients with LM had a higher ratio of EGFR L858R than 19del mutation (50.0% vs 25.0%). Most patients with positive plasma ctDNA results were male (p = 0.058) and in an unstable state (p = 0.003).

Conclusion

Our study indicated that the CSF ctDNA detected by NGS may reflect the molecular characteristics and heterogeneity of NSCLC-LM. Timely screening of patients with NSCLC for CSF ctDNA, especially for patients with positive plasma ctDNA, may facilitate the early detection of LM. Furthermore, patients with the EGFR 19del may have a higher risk of developing BPM.

Treatment of Non-Small Cell Lung Cancer with Atypical EGFR Mutations

OPINION STATEMENT

EGFR tyrosine kinase inhibitors (TKI) should always be considered when treating advanced/metastatic non-small cell lung cancer (NSCLC) with atypical EGFR mutations. The first choice of TKI depends on the specific mutation(s) present and its effect on structure and function of the EGFR protein. Afatinib is the only EGFR TKI currently FDA approved for atypical EGFR mutations and has the strongest data to support its use in PACC mutations, a subgroup of atypical EGFR mutations which includes G719X and S7681. Dacomitinib may also be an option for these mutations given similar efficacy to afatinib. In contrast, for classical-like mutations such as L861Q, osimertinib should be considered the first choice given that their behavior mimics that of the classical mutations exon 19 deletion and L858R. Osimertinib should also be utilized in the setting of a concurrent T790M mutation. Superior CNS penetrance and well managed toxicity profile may also be reasons to consider osimertinib. Given that the choice of TKI may depend on the specific mutation, it is crucial that every patient diagnosed with NSCLC undergo comprehensive sequencing to identify these mutations.

The novel EGFR mutations (p.E746_S752delinsI, p.T751_I759delinsG, p.L747_S752delinsAA) in patients with non-small cell lung cancer and the clinical treatment strategy: three case reports

Epidermal growth factor receptor (EGFR) is an established driver gene in non-small cell lung cancer (NSCLC) and the common Exon 19 del mutation (p.E746_A750 del) has exhibited remarkable responses for EGFR tyrosine kinase inhibitors (TKIs). However, there is even less comprehension of the treatment strategy in NSCLC patients harboring uncommon Exon 19 delins mutation. Here, we identified three novel EGFR Exon 19 mutations (p.E746_S752delinsI, p.T751_I759delinsG, p.L747_S752delinsAA), and described the clinical treatment process. To our knowledge, the EGFR p.E746_S752delinsI mutation of the patient with advanced NSCLC could benefit from the treatment with Icotinib. Otherwise, for the NSCLC patients with early-stage, one harboring p.T751_I759delinsG mutation had an excellent recovery and the other harboring p.L747_S752delinsAA experienced a relapse after receiving horacoscopic radical resection, which means the patients with different Exon 19 delins mutation might have different prognosis. Our study also demonstrated that next-generation sequencing (NGS) is a crucial tool in guiding clinical treatment decisions in NSCLC. Furthermore, the real incidence of these mutation is not known, the routinely use of NGS surely will increase the detection of EGFR del-ins respect to the old tools used to screen for EGFR mutations.

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.

Comprehensive profiling of EGFR mutation subtypes reveals genomic-clinical associations in non-small-cell lung cancer patients on first-generation EGFR inhibitors

Common sensitizing mutations in epidermal growth factor receptor (cEGFR), including exon 19 deletions (19-Del) and exon 21 L858R substitution, are associated with high sensitivity to EGFR-TKIs in NSCLC patients. The treatment for NSCLC patients with uncommon EGFR (uEGFR) mutations remains a subject of debate due to heterogeneity in treatment responses. In this manuscript, the targeted next-generation sequencing (NGS) data of a large cohort of EGFR-mutated NSCLC patients was assessed to elucidate genomic profiles of tumors carrying cEGFR or uEGFR mutations. The results showed that NSCLC patients with uEGFR mutations were more likely to harbor co-occurring genetic alterations in the Hippo pathway and a higher TMB compared with cEGFR-positive patients. Smoking-related mutations were found to significantly enriched in uEGFR-positive patients. Subgroup analyses were performed to identify potential prognostic biomarkers in patients harboring various EGFR subtype mutations. L858R-positive patients with co-existing ARID2 mutations had shorter progression-free survival (PFS) than those who were L858R- or 19-Del-positive but ARID2-negative (median: 2.3 vs. 12.0 vs. 8.0 months, P = 0.038). Furthermore, mutational profiles, such as top frequently mutated genes and mutational signatures of patients with various EGFR subtype mutations were significantly different. Our study analyzed the mutational landscape of NSCLC patients harboring cEGFR and uEGFR mutations, revealing specific genomic characteristics associated with uEGFR mutations that might explain the poor prognosis of first-generation EGFR-TKIs.

Molecular characteristics and prognostic factors of leptomeningeal metastasis in non-small cell lung cancer

BACKGROUND

Non-small cell lung cancer with leptomeningeal metastasis (NSCLC-LM) is emerging as a new management challenge for oncologists and is associated with poor prognosis. This study aimed to investigate the molecular characteristics and prognostic factors of NSCLC-LM.

METHODS

This retrospective study included 97 patients with NSCLC-LM between January 2015 and October 2021. Progression-free survival (PFS) and overall survival (OS) were evaluated. Gene mutations were detected by next-generation sequencing (NGS).

RESULTS

The median PFS and OS were 8.4 (95 % confidence interval [CI]: 4.839-11.901) and 14.0 (95 % CI: 9.254-18.746) months, respectively. Sixty-seven patients harboured epidermal growth factor receptor-mutated (EGFRm): L858R (34), 19del (29), T790M (13), and G719C with L861Q (1). Other mutations included ALK (5), ROS1 (3), KRAS (1), TP53 (14), MET amplification (6). The detection rate and types of circulating tumour DNA (ctDNA) in the cerebrospinal fluid (CSF) samples were higher than the paired plasma samples. Patients with EGFR mutations had a longer median OS than those without mutations (19.0 vs. 13.0 months, P = 0.015). Patients with gene mutations had shorter median OS than those without mutations, such as ALK (11.8 vs. 19.9 months, P = 0.014), ROS1 (12.7 vs. 19.8 months, P = 0.014), KRAS (4.0 vs. 19.0 months, P = 0.005), TP53 (15.0 vs. 19.0 months, P = 0.014), and MET amplification (6.0 vs. 19.0 months, P = 0.003). Multivariate analysis indicated that MET amplification was an independent predictor of poor survival. Along with Eastern Cooperative Oncology Group Performance Status (ECOG PS) ≥ 3, LM accompanied with brain parenchymal metastasis (BPM), extracranial disease, and seizures were independent predictors of poor survival, whereas intrathecal chemotherapy, and third-generation EGFR-TKIs were independent predictors of favorable survival.

CONCLUSIONS

CSF ctDNA detected using NGS had a high sensitivity for NSCLC-LM, showing high potential in detecting driver and drug-resistant gene mutations. Genomic profiles, combined with clinically relevant prognostic factors, will guide individualised treatments and improve the outcomes of NSCLC-LM patients.

Clinical outcomes of gefitinib and erlotinib in patients with NSCLC harboring uncommon EGFR mutations: A pooled analysis of 438 patients

BACKGROUND

The purpose of this study was to investigate the outcomes of gefitinib and erlotinib in patients with non-small cell lung cancer (NSCLC) with uncommon epidermal growth factor receptor (EGFR) mutations.

METHODS

Relevant researches were identified by a literature search of the PubMed database. Patients with EGFR mutations other than exon 19 deletion and L858R were eligible for the study. Clinical outcomes included objective response rate (ORR), progression free survival (PFS), and overall survival (OS). We categorized all uncommon EGFR mutations as: single uncommon EGFR mutations and compound mutations that containing 2 or more kinds of EGFR mutations. We also assessed outcomes in patients categorized by EGFR-TKIs: (1) gefitinib group; (2) erlotinib group.

RESULTS

A total of 438 patients with NSCLC harboring uncommon EGFR mutations were included in this study. The ORR for gefitinib and erlotinib was 43.8 %, with a median PFS (mPFS) of 6.00 months and a median OS (mOS) of 20.50 months. Patients with compound mutations had an ORR of 56.3 % and an mPFS of 8.10 months. Both of them were significantly better than these in patients with single uncommon EGFR mutation, which were 29.3 % and 3.90 months, respectively (odds ratio (ORa): 2.74, 95 % confidence interval (CI): 1.86-4.05, P < 0.001; hazard ratio (HR): 0.58, 95 % CI: 0.48-0.71, P < 0.001). Moreover, patients with compound mutations containing 19 deletion or L858R had a superior response and survival benefits compared to patients with other compound mutation patterns. In addition, the gefitinib group showed a favorable efficacy advantage (P = 0.003) and PFS benefit (P = 0.021) compared to the erlotinib group.

CONCLUSIONS

Uncommon EGFR mutations exhibit favorable but inconsistent treatment responses and survival outcomes to gefitinib and erlotinib, which are closely related to the mutation pattern, the cooccurring partner mutant genes, and the type of EGFR-TKIs received.

"Sandwich" Strategy to Intensify EGFR Blockade by Concurrent Tyrosine Kinase Inhibitor and Monoclonal Antibody Treatment in Highly Selected Patients

EGFR TKIs are not curative, and targeted resistance inevitably results in therapeutic failure. Additionally, there are numerous uncommon EGFR mutations that are insensitive to EGFR TKIs, and there is a lack of clinical strategies to overcome these limitations. EGFR TKI and mAbs target EGFR at different sites, and a combination regimen for delaying/preventing resistance to targeted therapy or obtaining more intensive inhibition for uncommon mutations at cellular, animal and human levels has been explored. This review critically focuses on a combination strategy for uncommon EGFR mutation-positive NSCLC, and discuss the preclinical data, clinical implications, limitations and future prospects of the combination strategy.

Targeting EGFR in melanoma - The sea of possibilities to overcome drug resistance

Melanoma is considered one of the most aggressive skin cancers. It spreads and metastasizes quickly and is intrinsically resistant to most conventional chemotherapeutics, thereby presenting a challenge to researchers and clinicians searching for effective therapeutic strategies to treat patients with melanoma. The use of inhibitors of mutated serine/threonine-protein kinase B-RAF (BRAF), e.g., vemurafenib and dabrafenib, has revolutionized melanoma chemotherapy. Unfortunately, the response to these drugs lasts a limited time due to the development of acquired resistance. One of the proteins responsible for this process is epidermal growth factor receptor (EGFR). In this review, we summarize the role of EGFR signaling in the multidrug resistance of melanomas and discuss possible applications of EGFR inhibitors to overcome the development of drug resistance in melanoma cells during therapy.

EGFR exon 20 insertion mutations in advanced non-small-cell lung cancer: current status and perspectives

Platinum-based chemotherapy was previously the first-choice treatment for lung cancer. The discovery of epidermal growth factor receptor (EGFR) gene mutations and the development of EGFR tyrosine kinase inhibitors (TKIs) marked the beginning of the targeted therapy era for non-small-cell lung cancer (NSCLC). Thirty percent of NSCLC patients carry EGFR gene mutations. For these advanced NSCLC patients, EGFR-TKIs are currently preferred for their superior activity and survival benefits over platinum-based chemotherapy. However, therapeutic efficacy is quite different in patients with EGFR exon 20 insertion (ex20ins) mutations versus common mutations. Patients with ex20ins mutations are insensitive to EGFR-TKIs and have poor prognosis. Some drugs targeting EGFR ex20ins mutations have been approved. Here, we systematically reviewed the recent clinical research of and treatments used for EGFR ex20ins mutations, summarized the latest data on emerging therapies, and discussed future prospects and treatments.

Clinical outcomes of advanced non-small cell lung cancer patients harboring distinct subtypes of EGFR mutations and receiving first-line tyrosine kinase inhibitors: brain metastasis and de novo T790M matters

Background

The clinical features, survival outcomes and patterns of treatment failure of advanced non-small cell lung cancer (NSCLC) patients harboring distinct subtypes of EGFR mutations and receiving first-line EGFR tyrosine kinases inhibitor (TKIs) are not fully understood.

Methods

Consecutive metastatic EGFR-mutant NSCLC patients receiving first-line EGFR-TKIs from October 2010 to March 2020 were enrolled and classified into two main groups based on the EGFR mutation subtypes: common mutation (L858R or exon 19 deletion), uncommon mutation (other EGFR mutations).

Results

Of the 1081 patients included, 74 (6.8%) harbored uncommon mutations. The baseline characteristics were generally balanced between the two groups, except that bone metastasis developed less frequently in patients with uncommon mutations (p = 0.02). No significant difference of survival outcomes was found between the two groups, except that among patients with baseline brain metastasis, the intracranial time to progression was significantly shorter in patients with uncommon mutations. Nine of the 17 patients with de novo T790M mutation received Osimertinib, whose overall survival tended to be longer than the remaining 8 patients without Osimertinib treatment (p = 0.08). The patterns of treatment failure were generally consistent between the two groups, except which patients with uncommon mutations had a higher risk developing progressive disease in the brain.

Conclusion

First-line EGFR-TKIs seemed to be less effective in controlling and preventing brain metastasis in patients with uncommon EGFR mutations and Osimertinib was associated with promising efficacy in patients with de novo T790M mutation, which warranted further validation.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12885-022-09245-5.

Structure-based classification predicts drug response in EGFR-mutant NSCLC

Epidermal growth factor receptor (EGFR) mutations typically occur in exons 18–21 and are established driver mutations in non-small cell lung cancer (NSCLC)^1–3. Targeted therapies are approved for patients with ‘classical’ mutations and a small number of other mutations^4–6. However, effective therapies have not been identified for additional EGFR mutations. Furthermore, the frequency and effects of atypical EGFR mutations on drug sensitivity are unknown^1,3,7–10. Here we characterize the mutational landscape in 16,715 patients with EGFR-mutant NSCLC, and establish the structure–function relationship of EGFR mutations on drug sensitivity. We found that EGFR mutations can be separated into four distinct subgroups on the basis of sensitivity and structural changes that retrospectively predict patient outcomes following treatment with EGFR inhibitors better than traditional exon-based groups. Together, these data delineate a structure-based approach for defining functional groups of EGFR mutations that can effectively guide treatment and clinical trial choices for patients with EGFR-mutant NSCLC and suggest that a structure–function-based approach may improve the prediction of drug sensitivity to targeted therapies in oncogenes with diverse mutations.

Structural classification of mutations in the epidermal growth factor receptor causing non-small cell lung cancer is a better predictor of patient outcomes following drug treatment than traditional exon-based classification.

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.

Improvement of EGFR Testing over the Last Decade and Impact of Delaying TKI Initiation

Background: Epidermal growth factor receptor (EGFR) is the most common oncogenic mutation in lung adenocarcinoma and tyrosine kinase inhibitors (TKIs) have been considered standard treatment for more than a decade. However, time to initiation of TKIs (TTIT) from diagnosis is often delayed and represents a challenge for clinicians. We aimed to assess the impact of TTIT on clinical outcomes and complications. Method: TTIT was defined as the time between confirmed advanced diagnosis and the initiation of a TKI. Complications during this pre-TKI period were retrospectively collected from all patients with EGFR-mutant non small cell lung cancer (NSCLC) in our institution. Results: 102 patients were diagnosed with EGFR mutated NSCLC between 2006 and 2019. The median PFS and OS were 12.9 and 22.5 months, respectively. TTIT was 5.7 months (95% CI 3.4–8) with a significant decrease in the latter years of this cohort. During the pre-TKI period, 23 patients received chemotherapy as first line treatment, of which 5 developed severe adverse events and 3 were not fit to receive TKI thereafter. Additionally, 29 patients had rapid clinical deterioration before initiation of first line TKI and 16 had to be hospitalized. Among the patients presenting a performance status deterioration, their prognosis was markedly affected compared to the remainder of the cohort (p = 0.01). Conclusion: Our real-world evidence study supports the concept that a delay to treat EGFR mutant NSCLC with TKIs is associated with adverse events, patient progression, hospitalization, and decreased overall survival. Rapid molecular diagnosis, including access to ctDNA technology may circumvent these deleterious delays.

Clinical Benefit of Tyrosine Kinase Inhibitors in Advanced Lung Cancer with EGFR-G719A and Other Uncommon EGFR Mutations

The optimal management of advanced non-small cell lung cancer (NSCLC) with noncanonical epidermal growth factor receptor (EGFR) mutations (i.e., exon 19 deletion and exon 21 L858R) is constrained by the heterogeneous behavior of individual uncommon mutations and limited prospective clinical data in this setting. Despite encouraging results with osimertinib from a recently published phase II trial from South Korea, afatinib remains the only currently approved drug for patients with tumors harboring uncommon EGFR mutations (i.e., S768I, L861Q, and/or G719X). When used at the standard dose of 40 mg daily, afatinib is associated with significant rates of treatment-related adverse events, leading to frequent dose reductions and treatment discontinuations. We report a case of a woman with advanced NSCLC harboring EGFR-G719A mutation treated with afatinib (at an off-label pulse dose strategy that merits further evaluation in prospective studies) with sustained partial response for 20 months with manageable expected toxicities. Subsequent disease progression was mediated by off-target pan-EGFR inhibitor (including osimertinib)-resistant KRAS mutation and not by acquisition of EGFR-T790M. We further present the current state of evidence in the literature behind use of first-, second-, and third-generation tyrosine kinase inhibitors and summarize the evolving spectrum of activity ascribed to osimertinib (and newer EGFR inhibitors with a more favorable therapeutic window and intracranial penetration) in this population of patients with advanced NSCLC and uncommon EGFR mutations. KEY POINTS: Uncommon EGFR mutations characterize a heterogeneous group of patients with advanced non-small cell lung cancer (NSCLC). Afatinib is the only currently U.S. Food and Drug Administration-approved drug for management of advanced NSCLC with uncommon EGFR mutations (S768I, L861Q, and/or G719X). Afatinib treatment at 40 mg daily is associated with high rates of adverse events and dose reductions; alternative strategies including pulse intermittent dosing should be evaluated prospectively. Osimertinib (with favorable safety profile and intracranial penetration) has shown promising results in this population in a phase II trial from South Korea; additional trials are ongoing.

Spectrum of uncommon and compound epidermal growth factor receptor mutations in non-small-cell lung carcinomas with treatment response and outcome analysis: A study from India

INTRODUCTION

Mutations in the tyrosine kinase domain of the epidermal growth factor receptor gene (EGFR) are key driver alterations in lung adenocarcinomas (ADCAs). Exon 19 deletions (exon19del) and exon 21 L858R (L858R) mutations account for 70-90 % of all such alterations and predict sensitivity to EGFR tyrosine kinase inhibitors (TKIs). However, the predictive value of uncommon and compound EGFR mutations for TKIs has not been clearly established.

OBJECTIVE

To assess the spectrum of EGFR mutations in non-small-cell lung carcinoma (NSCLC), and to compare the treatment responses and outcomes among single common, single uncommon, and compound mutations.

METHOD

The study was of combined retrospective (January 2010-December 2015) and prospective (January 2016-February 2020) design spanning 10 years. Tumor samples from TKI-naive NSCLC patients were tested for EGFR mutations by a qPCR-based method. Objective response rates (ORRs) and survival outcomes were analyzed.

RESULT

In total, 1227 tumor samples were tested. EGFR mutations were detected in 391 samples (31.8 %), and included 79.5 % (311/391) single common (exon19del/L858R), 6.6 % (26/391) single uncommon (non-exon19del/L858R), and 13.8 % (54/391) compound mutations. Exon 20 T790M mutations were most prevalent among uncommon/compound mutations (40/391, 10.2 %). Overall, patients with single uncommon/compound mutations responded poorly to both EGFRTKI (47 % ORR) and chemotherapy (43 % ORR), with significantly shorter time to progression (median 7 months) compared to those with exon19del/L858R mutations (median 14.7 months). Patients with baseline T790M mutations (single/compound) were least responsive to EGFR TKIs (11 % ORR) and chemotherapy (27 % ORR) and showed the shortest progression-free survival compared to other uncommon and compound mutations.

CONCLUSION

Approximately one fifth of EGFR-mutant patients harbor uncommon and compound mutations. Unlike those with exon19del/L858R, these patients-particularly those with baseline T790M mutations-show significantly inferior response rates to treatment (EGFR TKI or chemotherapy) and early disease progression.

Clinical Activity of Afatinib in Patients With Non-Small-Cell Lung Cancer Harboring Uncommon EGFR Mutations: A Spanish Retrospective Multicenter Study

INTRODUCTION

Uncommon epidermal growth factor receptor (EGFR) mutations (u-EGFRm) are a heterogeneous group of molecular alterations and have also been reported as comutations with other EGFR mutations (complex mutations) in non-small-cell lung cancer (NSCLC). Afatinib has shown activity against some u-EGFRm, and we examined its efficacy in Spanish clinical practice.

PATIENTS AND METHODS

Data of 67 patients with advanced NSCLC with u-EGFRm treated with afatinib between 2012 and 2017 at 23 Spanish institutions were reviewed. u-EGFRm were analyzed as complex mutations (group A), EGFR exon 20 insertions (ins20; group B), or single mutations (group C). Efficacy was evaluated in terms of overall survival (OS) and tumor response.

RESULTS

Group A complex u-EGFRm consisted of double mutations of G719X+E709F, G719X+S768I, G719X+L861Q, L858R+T790M, L858R+S768I, L858R+S765I, del19+S768I, del19+L747S, or R776C+L861Q. No differences in clinical characteristics were found between groups A (n = 20), B (n = 23), and C (n = 24). Afatinib was administered as first-line therapy in 80% of patients. Median time of receipt of therapy was 4.2 months (range, 2.0-12.9 months). Median OS for the entire cohort was 19.9 months (95% confidence interval, 9.7, 30.1). Hazard ratios for OS were 0.26 (95% confidence interval, 0.10, 0.71; P = .008) and 0.40 (95% confidence interval, 0.17, 0.95; P = .037) for groups A and C compared to B, respectively. Response was significantly higher in groups A (70%) and C (54%) compared to B (13%; pairwise comparison P < .001 and .008, respectively).

CONCLUSION

In clinical practice, afatinib was active in patients with u-EGFRm NSCLC, particularly in complex and single mutations. Further strategies are needed for patients with ins20, a subgroup u-EGFRm with a lower clinical benefit with afatinib.

Clinical outcome of treatment of metastatic non-small cell lung cancer in patients harboring uncommon EGFR mutation

Background

Uncommon epidermal growth factor receptor (EGFR)-mutant non-small cell lung cancer (NSCLC) is a rare subset of NSCLC. The aim of this study was to investigate the prevalence, characteristics, and clinical outcomes of metastatic NSCLC harboring uncommon EGFR mutation at Thailand’s largest national tertiary hospital. The secondary objective was to compare treatment efficacy between EGFR-tyrosine kinase inhibitor (EGFR-TKI) and chemotherapy.

Methods

This retrospective chart review included patients that were tested for EGFR-mutation NSCLC during 2014–2018. Patient demographic and clinical data, treatment data, and outcome data were collected and analyzed.

Results

Of the 681 patients that were evaluated for EGFR mutation, 317 (47.0%) had EGFR-mutant NSCLC, and 28 (8.8%) of those harbored uncommon EGFR mutations. The median follow-up was 19.1 months. History of tobacco use was reported in 50% of patients. The most common single mutation among uncommon EGFR was exon 20 insertion (n = 6), followed by L861Q (n = 5) and G719X (n = 4). Thirteen (46%) patients had compound mutations. One hundred percent of male patients with G719X mutation were smokers. Sixteen of 28 patients were treated with EGFR-TKI. Most received first-generation EGFR-TKI, and 29% were treated with chemotherapy alone. The objective response rate was 37.5% in the EGFR-TKI group. Median progression-free survival (PFS) in the EGFR-TKI group was 10.2 months. Median PFS among the 8 patients in the chemotherapy group that received first-line platinum doublet was 6.5 months. Three-year overall survival (OS) among 28 patients was 34%. Three-year OS was significantly better in patients treated with EGFR-TKI.

Conclusions

Uncommon EGFR mutations was detected in 8.8% of EGFR-mutant NSCLC. Exon 20 insertion was the most common mutation, and 50% of patients had history of tobacco use. First- or second-generation EGFR-TKI demonstrated greater OS benefit than platinum-doublet chemotherapy among patients harboring uncommon EGFR-mutant NSCLC. Survival outcomes were comparable to those reported from previous large cohort studies.

Treatment of uncommon EGFR mutations in non-small cell lung cancer: new evidence and treatment

Sensitizing mutations in epidermal growth factor receptor (EGFR) are associated with positive responses to anti-EGFR-targeted therapy, leading to a new era of treatment for non-small cell lung cancer (NSCLC). Exon 19 deletions and exon 21 L858R substitutions are the most common mutations, accounting for approximately 90% mutations in NSCLC; these are termed classic mutations and result in high sensitivity to tyrosine kinase inhibitors (TKIs). Other EGFR mutations are termed uncommon EGFR mutations, of which G719X, S768I, L861Q, exon 20 insertions, and complex mutations are the most frequent. G719X, S768I, and L861Q are point mutations and those that exist with complex mutations are sensitive to first-generation TKIs. A prospective analysis demonstrated that afatinib, a second-generation TKI, led to a better prognosis in some patients with NSCLC compared to first-generation TKIs. Chemotherapy used to be the traditional choice for patients carrying exon 20 insertions; however, with the development of novel targeted drugs, the role of chemotherapy is changing. Tremendous progress has also been made in clinical trials on immunotherapy treatment of uncommon EGFR mutations. The treatment for patients with NSCLC harboring uncommon EGFR mutations remains a subject of debate and the sensitivity of uncommon EGFR mutations to TKIs is still unclear. Here, we summarized recent data in the literature and provide an overview of the clinical characteristics, incidence, and outcomes of patients harboring G719X, S768I, L861Q, exon 20 insertions, and complex mutations who were treated with TKIs, chemotherapy, or immunotherapy.

Genomic Signature of Driver Genes Identified by Target Next-Generation Sequencing in Chinese Non-Small Cell Lung Cancer

BACKGROUND

Non-small cell lung cancer (NSCLC) is one of the most common human malignancies and the leading cause of cancer-related death. Over the past few decades, genomic alterations of cancer driver genes have been identified in NSCLC, and molecular testing and targeted therapies have become standard care for lung cancer patients. Here we studied the unique genomic profile of driver genes in Chinese patients with NSCLC by next-generation sequencing (NGS) assay.

MATERIALS AND METHODS

A total of 1,200 Chinese patients with NSCLC were enrolled in this study. The median age was 60 years (range: 26-89), and 83% cases were adenocarcinoma. NGS-based genomic profiling of major lung cancer-related genes was performed on formalin-fixed paraffin-embedded tumor samples and matched blood.

RESULTS

Approximately 73.9% of patients with NSCLC harbored at least one actionable alteration recommended by the National Comprehensive Cancer Network guideline, including epidermal growth factor receptor (EGFR), ALK, ERBB2, MET, BRAF, RET, and ROS1. Twenty-seven patients (2.2%) harbored inherited germline mutations of cancer susceptibility genes. The frequencies of EGFR genomic alterations (both mutations and amplification) and ALK rearrangement were identified as 50.1% and 7.8% in Chinese NSCLC populations, respectively, and significantly higher than the Western population. Fifty-six distinct uncommon EGFR mutations other than L858R, exon19del, exon20ins, or T790M were identified in 18.9% of patients with EGFR-mutant NSCLC. About 7.4% of patients harbored both sensitizing and uncommon mutations, and 11.6% of patients harbored only uncommon EGFR mutations. The uncommon EGFR mutations more frequently combined with the genomic alterations of ALK, CDKN2A, NTRK3, TSC2, and KRAS. In patients <40 years of age, the ALK-positive percentage was up to 28.2%. Moreover, 3.2% of ALK-positive patients harbored multi ALK rearrangements, and seven new partner genes were identified.

CONCLUSION

More unique features of cancer driver genes in Chinese NSCLC were identified by next-generation sequencing. These findings highlighted that NGS technology is more feasible and necessary than other molecular testing methods, and suggested that the special strategies are needed for drug development and targeted therapy for Chinese patients with NSCLC.

IMPLICATIONS FOR PRACTICE

Molecular targeted therapy is now the standard first-line treatment for patients with advanced non-small cell lung cancer (NSCLC). Samples of 1,200 Chinese patients with NSCLC were analyzed through next-generation sequencing to characterize the unique feature of uncommon EGFR mutations and ALK fusion. The results showed that 7.4% of EGFR-mutant patients harbored both sensitizing and uncommon mutations and 11.6% harbored only uncommon mutations. Uncommon EGFR mutations more frequently combined with the genomic alterations of ALK, CDKN2A, NTRK3, TSC2, and KRAS. ALK fusion was more common in younger patients, and the frequency decreased monotonically with age. 3.2% of ALK-positive patients harbored multi ALK rearrangement, and seven new partner genes were identified.

Efficacy and long-term survival of advanced lung adenocarcinoma patients with uncommon EGFR mutations treated with 1st generation EGFR-TKIs compared with chemotherapy as first-line therapy

PURPOSE

This study aims to understand the effects and long-term survival of 1st generation epithelial growth factor receptor tyrosine kinase inhibitors(EGFR-TKI)or platinum-based chemotherapy as first-line therapy in advanced lung adenocarcinoma patients with uncommon EGFR mutations.

PATIENTS AND METHODS

Specimens from 4276 advanced (IIIB/IV) patients were diagnosed with lung adenocarcinoma and underwent EGFR gene detection at the Affiliated Cancer Hospital of Zhengzhou University. The clinic characteristics, survival outcomes data, treatment outcomes and data of subsequent therapies after first-line treatment were collected of patients with uncommon EGFR mutations. The results were compared with common EGFR mutations.

RESULTS

For patients with uncommon EGFR mutations, EGFR-TKIs or platinum-based chemotherapy as first-line therapy, showed no difference in objective response rate (ORR 33% vs 27.1% P = 0.499) and disease control rate (DCR 76.5% vs 87.5%, P = 0.194). EGFR-TKIs showed a superior progression-free survival than chemotherapy (median PFS, 7.2 vs 4.9 mt, HR = 0.604; P = 0.0088). Interestingly, compared with chemotherapy, we found that overall survival (median OS, 14.3 vs 20.7 mts, HR = 1.759; P = 0.0336) was significantly worse in patients with EGFR-TKIs. Multivariate analysis showed that extra metastases (HR = 2.240, P = 0.001) and smoking history (HR = 2.048, P = 0.013) were independent prognostic factors for OS in lung adenocarcinoma patients with EGFR uncommon mutations.

CONCLUSIONS

Compared with chemotherapy, use of the 1st generation of EGFR-TKIs as first-line therapy can improve the short-term efficacy of patients with EGFR uncommon mutations advanced lung adenocarcinoma, but platinum-based chemotherapy showed a longer overall survival.

Outcome of uncommon EGFR mutation positive newly diagnosed advanced non-small cell lung cancer patients: a single center retrospective analysis

Background

The significance of uncommon EGFR mutations in newly diagnosed advanced non-small-cell lung cancer (NSCLC) patients is incompletely known. We aimed to analyze the demographic profile, outcome, and treatment attributes of these patients.

Patients and methods

We retrospectively surveyed 5,738 advanced NSCLC patients who underwent EGFR testing in our center from 2013 to 2017 by in-house primer probes on real time PCR platform. Descriptive data were accumulated from electronic medical records. Survival plot was calculated using Kaplan-Meier method and compared between groups using log-rank test.

Results

Out of 1,260 EGFR mutation-positive patients, 83 (6.58%) had uncommon mutations in isolation or in various combinations. Uncommon mutations were more frequent in men, never-smokers, and adenocarcinomas. Overall, exon 18 G719X, exon 20 insertion, exon 20 T790M, exon 20 S768I, and exon 21 (L858R/L861Q) were present in 9.6%, 19.3%, 12%, 3.6%, and 3.6% patients, respectively. Dual mutation positivity was found in 50.6% patients. On classifying patients as per tyrosine kinase inhibitor (TKI) sensitivity, it was found that majority of the patients had a combination TKI sensitive and insensitive mutations. The median duration of follow-up was 13 months. Five patients were lost to follow-up. Median progression-free survival on first line therapy was 6.7 months (95% CI: 4.8-8.5). Median overall survival (OS) of patients who received TKI during the course of their disease was 20.2 months (95% CI: 11.4-28.9). Median overall survival (mOS) of the entire cohort was 15.8 months (95% CI: 10.1-21.5). Among all uncommon mutations, patients with dual mutations did better, with an mOS time of 22.6 months (95% CI: 8.2-37.0, P=0.005). It was observed that TKI sensitive/TKI insensitive dual mutations had a superior OS of 28.2 months (95% CI: 15.2-41.2, P=0.039) as compared to TKI sensitive and TKI insensitive EGFR mutations.

Conclusion

Uncommon EGFR mutations constitute a heterogeneous group, hence, it is imperative to understand each subgroup more to define optimal treatment.

PD-L1 expression and its effect on clinical outcomes of EGFR-mutant NSCLC patients treated with EGFR-TKIs

Objective:

Epidermal growth factor receptor (EGFR) activation was reported to upregulate programmed death-ligand 1 (PD-L1) expression in lung cancer cells and subsequently contribute to immune escape, indicating its critical role in EGFR-driven lung tumors. This study characterized PD-L1 expression in patients with surgically resected EGFR-mutant non-small cell lung cancer (NSCLC). The effect of PD-L1 expression on clinical outcomes was also investigated in advanced EGFR-mutant NSCLC treated with EGFR-tyrosine kinase inhibitors (TKIs).

Methods:

In total, 73 patients with surgically resected NSCLC and EGFR mutations were identified. PD-L1 expression and CD8+ tumor-infiltrating lymphocyte (TIL) density were assessed by immunohistochemistry. A literature review of publications that assessed the predictive and prognostic value of PD-L1 expression in advanced EGFR-mutant NSCLC patients treated with EGFR-TKIs was performed.

Results:

Nineteen (26.0%) patients were positive for PD-L1 expression, which was significantly associated with concomitant KRAS mutation (P = 0.020) and marginally associated with higher CD8+ TILs density (P = 0.056). Positive PD-L1 expression was associated with markedly inferior overall survival (OS) in multivariate analysis (P = 0.032). The combination of PD-L1 and CD8+ TILs expression could be used to stratify the population into three groups with distinct prognoses. A meta-analysis of six publications showed that positive PD-L1 expression was not associated with OS [hazard ratio (HR) = 0.90; 95% confidence interval (CI), 0.42–1.38] or progression-free survival (HR = 1.03; 95 CI, 0.73–1.33) in advanced EGFR-mutant NSCLC patients receiving EGFR-TKIs.

Conclusions:

PD-L1 expression tended to correlate with CD8+ TIL expression, concomitant KRAS mutation, and poor survival in surgically resected EGFR-mutant NSCLC. PD-L1 expression was neither the predictive nor the prognostic factor in advanced EGFR-mutant NSCLC patients treated with EGFR-TKIs.