EGFR-mutated Non-small Cell Lung Carcinoma Research Articles

Antibody-Drug Conjugates as Novel Therapeutic Agents for Non-Small Cell Lung Carcinoma with or without Alterations in Oncogenic Drivers.

Antibody-drug conjugates (ADCs) are an emerging class of therapeutics for lung cancer, and several are currently in development for this malignancy. The structure of these molecules is based on an antibody that targets a protein on the lung cancer cell surface and a cytotoxic payload attached by a linker. Many protein targets, including TROP2, c-MET, CEACAM5, HER2, and HER3 have been identified. In metastatic non-small cell lung carcinoma (NSCLC) without alterations in oncogenic drivers, platinum-based chemotherapy and immune checkpoint inhibitors (ICIs) targeting the programmed death-1/programmed death-ligand 1 (PD1/PDL1) interaction are the standard first-line treatments. In patients with EGFR-mutated or ALK-rearranged NSCLC, tyrosine kinase inhibitors (TKIs) are recommended. However, although the prognosis of patients with metastatic NSCLC differs between such with and without alterations in oncogenic drivers, most patients eventually experience disease progression. A novel therapeutic class is needed in routine practice to overcome the mechanisms of resistance to ICIs and EGFR/ALK TKIs. Several ADCs have already been approved for other cancers, such as breast cancer and urothelial carcinoma. This review summarizes the knowledge about the efficacy and tolerance profiles of ADCs targeting TROP2, HER2, HER3, CEACAM5 and c-MET in metastatic NSCLC with and without alterations in oncogenic drivers.

A destabilizing Y891D mutation in activated EGFR impairs sensitivity to kinase inhibition

EGFR tyrosine kinase inhibitors (TKIs) have transformed the treatment of EGFR-mutated non-small cell lung carcinoma (NSCLC); however, therapeutic resistance remains a clinical challenge. Acquired secondary EGFR mutations that increase ATP affinity and/or impair inhibitor binding are well-described mediators of resistance. Here we identify a de novo EGFR Y891D secondary alteration in a NSCLC with EGFR L858R. Acquired EGFR Y891D alterations were previously reported in association with resistance to first generation EGFR TKIs. Functional studies in Ba/F3 cells demonstrate reduced TKI sensitivity of EGFR L858R + Y891D, with the greatest reduction observed for first and second generation TKIs. Unlike other EGFR mutations associated with TKI resistance, Y891D does not significantly alter ATP affinity or promote steric hindrance to inhibitor binding. Our data suggest that the Y891D mutation destabilizes EGFR L858R, potentially generating a population of misfolded receptor with preserved signaling capacity but reduced sensitivity to EGFR inhibitors. These findings raise the possibility of protein misfolding as a mechanism of resistance to EGFR inhibition in EGFR-mutated NSCLC.

A Prospective Cohort Study Assessing the Relationship between Plasma Levels of Osimertinib and Treatment Efficacy and Safety.

Osimertinib is a standard treatment for patients with EGFR-mutated non-small cell lung carcinoma (NSCLC). We evaluated the relationship between plasma osimertinib concentrations and treatment outcome in patients with NSCLC for this cohort study. The plasma levels of osimertinib and its metabolite AZ5104 were measured a week after the start of treatment (P1). The primary endpoint was to evaluate the correlation between plasma concentration and adverse events (AEs). The correlation with treatment efficacy was one of the secondary endpoints. In patients with CNS metastases, the concentration in the cerebrospinal fluid was also measured. Forty-one patients were enrolled. The frequency of AEs was highest for rash, followed by anorexia and thrombocytopenia. Thirty-eight cases provided measurements for P1. The median plasma concentration of osimertinib was 227 ng/mL, and that of AZ5104 was 16.5 ng/mL. The mean CNS penetration rate of two cases was 3.8%. The P1 in the group with anorexia was significantly higher than that in the group without anorexia (385.0 ng/mL vs. 231.5 ng/mL, p = 0.009). Divided into quartiles by P1 trough level, Q2 + Q3 (164-338 ng/mL) had longer PFS, while Q1 and Q4 had shorter PFS. An appropriate plasma level of osimertinib may avoid some adverse events and induce long PFS. Further large-scale trials are warranted.

Association of PD-L1 tumor proportion score ≥20% with early resistance to osimertinib in patients with EGFR-mutated NSCLC.

The relationship between epidermal growth factor receptor tyrosine kinase inhibitor (EGFR-TKI) resistance, including osimertinib, and programmed cell death-ligand 1 (PD-L1) expression status in EGFR-mutated non-small cell lung carcinoma (NSCLC) remains unclear. We retrospectively analyzed 64 patients with unresectable advanced or metastatic NSCLC carrying EGFR exon 19 deletions (ex19del) or EGFR exon 21 L858R substitutions (L858R) who received osimertinib as the first-line treatment. We compared progression-free survival (PFS) between eligible patients with PD-L1 tumor proportion scores (TPS) ≥20% and PD-L1 TPS <20% using the Kaplan-Meier survival plots with a log-rank test. Multivariate analysis was performed to examine the poor prognostic factors of PFS. The PD-L1 TPS ≥20% group included 22 cases (median [range] age: 70.5 [33-86] years; 10 women [45.5%]; 11 current or ex-smokers [50%]); ECOG performance status (PS) of 0-1/2/3/4 was noted in 16/4/1/1 patients, respectively. The PD-L1 TPS <20% group included 42 patients (median [range] age 73 [43-88] years; 29 women [69%]; 12 current or ex-smokers [28.6%]); ECOG PS of 0-1/2/3/4 was noted in 33/6/3/0 cases, respectively. The median PFS was 9.1 and 28.1 months in the PD-L1 TPS ≥20% and PD-L1 TPS <20% groups, respectively (log-rank p = 0.013). Multivariate analysis revealed that PD-L1 TPS ≥20% was associated with PFS (hazard ratio: 2.35, 95% confidence interval: 1.09-5.08, p = 0.030). PD-L1 TPS ≥20% in patients with EGFR-mutated NSCLC may be associated with early resistance to osimertinib.

Undertreatment with Osimertinib in patient with multiple chemical sensitivity. A case report.

Multiple chemical sensitivity (MCS), is a syndrome characterised by increased sensitivity to the exposure of environmental chemicals (1). There are considerable difficulties in reaching a good estimate of the prevalence of disease and the main pathogenetic hypotheses take into account both the organic and psychiatric/psychological factors. Treatment with epidermal growth factor tyrosine kinase receptor inhibitors (tkis), like Osimertinib, results in improved progression-free survival (PFS) compared to chemotherapy, in Non-small-cell lung carcinoma (NSCLC) with epidermal growth factor receptor (EGFR) mutation (2). We describe the case of a 74 year old woman with history of MCS and fibromyalgia in treatment with Osimertinib for EGFR-mutated NSCLC. Patient initially refused any form of active therapy for lung cancer, but thanks to teamwork and the important support of the psychologist, the patient decided to start treatment with Osimertinib at a reduced dose, not 80 mg but 40 mg. Subsequently, after few days , of his own free will and without informing the staff physicians, the patient changed the treatment schedule by taking one quarter of the dose of the medicine every other day, justifying this choice in therapeutic modification because of her fear and intolerance to any type of medicine and/ or chemical substance, being influenced by MCS. Despite the changes in the treatment plan, a PET scan performed after two months showed a sigificative lung response and the stability of bone metastases. Discussion. Our case describes a significative response with Osimertinib despite the change in dosage and schedule in a patient with MCS. Our experience deserves to be considered in the light of its particularity and uniqueness as it shows an excellent response to treatment with Osimertinib despite the change made to the dosage and schedule, in a patient presenting in her medical history this rare pathological condition: MCS syndrome.

Cellular plasticity and immune microenvironment of malignant pleural effusion are associated with EGFR-TKI resistance in non–small-cell lung carcinoma

Malignant pleural effusion (MPE) is a complication of lung cancer that can be used as an alternative method for tissue sampling because it is generally simple and minimally invasive. Our study evaluated the diagnostic potential of non-small-cell lung carcinoma (NSCLC)-associated MPE in terms of understanding tumor heterogeneity and identifying response factors for EGFR tyrosine kinase inhibitor (TKI) therapy. We performed a single-cell RNA sequencing analysis of 31,743 cells isolated from the MPEs of 9 patients with NSCLC (5 resistant and 4 sensitive to EGFR TKI) with EGFR mutations. Interestingly, lung epithelial precursor-like cells with upregulated GNB2L1 and CAV1 expression were enriched inthe EGFR TKI-resistant group. Moreover, GZMK upregulated transitional effector Tcells, and plasmacytoid dendritic cells were significantly enriched in the EGFR TKI-resistant patients. Our results suggest that cellular plasticity and immunosuppressive microenvironment in MPEs are potentially associated with the TKI response of patients with EGFR-mutated NSCLC.

1249P Pharmacokinetic and dose finding study of osimertinib in patients with impaired renal function and low body weight

This dose-finding study of osimertinib aimed to investigate the safety, pharmacokinetics (PK), and recommended dose (RD) for EGFR-mutated non-small cell lung carcinoma (NSCLC) patients with impaired renal function and low body weight.

Efficacy and Safety of Combination Treatment With Apatinib and Osimertinib After Osimertinib Resistance in Epidermal Growth Factor Receptor-Mutant Non-small Cell Lung Carcinoma-A Retrospective Analysis of a Multicenter Clinical Study.

Currently, there are limited treatment options for patients who developed resistance to osimertinib, a third-generation epidermal growth factor receptor (EGFR) inhibitor. Resistance to EGFR inhibitors is frequently associated with enhanced vascular endothelial growth factor (VEGF) levels. This multicenter, retrospective study aimed to evaluate the efficacy of the combination treatment with apatinib and osimertinib in 39 patients with EGFR-mutant non-small cell lung carcinoma (NSCLC) who developed osimertinib resistance. The patients received the combination of oral apatinib 250 mg qd and osimertinib 80 mg qd. The efficacy was evaluated after the first month then every 2 months thereafter. The primary endpoint was progression-free survival (PFS). The overall response rate (ORR) and the disease control rate (DCR) of the combination of apatinib and osimertinib was 12.8% (5/39) and 79.5% (31/39), respectively. The median PFS was 4 months [95% confidence interval (CI): 3.5–4.5 months]. Fourteen patients were administered with at least 6 months of combination therapy, and 11 of them remained on treatment programs. The 6-month PFS rate was 38%. Nine patients underwent biopsies after failing osimertinib treatment, and five of six patients with TP53 mutations had PFS of less than 3 months. The spectrum of resistance to osimertinib mechanisms included c-mesenchymal-epithelial transition factor (c-Met) amplification, phosphatidylinositol-4,5-bisphosphate 3-kinase catalytic subunit alpha (PIK3CA) gain-of-function mutation, phosphatase and tensin homolog (PTEN) loss-of-function mutation, Erb-B2 receptor tyrosine kinase 2 (ERBB2) amplification, and insulin-like growth factor 1 receptor (IGF1R) mutation. The most common adverse events were hypertension (30.7%, 12/39), diarrhea (15.4%, 6/39), and proteinuria (12.8%, 5/39). The combination of apatinib and osimertinib improved the ORR and the DCR of patients with osimertinib-refractory EGFR-positive NSCLC, thus making it a reasonable treatment choice after the development of osimertinib resistance.

EGFR and PDL1: A Match (Not) Made in Heaven-A Real-World Retrospective Analysis of PDL1 Expression in EGFR-Mutated NSCLC.

EGFR (epidermal growth factor receptor) mutant NSCLC (non-small cell lung carcinoma) comprises 35-40% of cases in the Asian NSCLC cohort, compared to 15-20% in the rest of the world. Improved response rates have been observed in terms of PFS (progression-free survival) and ORR (overall response rate) when treated with EGFR TKIs (tyrosine kinase inhibitors). However, resistance eventually ensues regardless of the generation of TKI used. Preclinical studies have reported that PDL1 (programmed death ligand1) is a downstream target of EGFR and is interposed by IL-6/JAK/STAT3 (interleukin-6/Janus kinase/signal transducer and activator of transcription3), NF-κB (nuclear factor kappa beta), and p-ERK1/2/p-c-Jun pathways. Hence, it may potentially be repressed by EGFR TKIs. In this retrospective exploratory analysis, we studied whether PDL1 expression affects efficacy of EGFR TKIs and clinical outcome in patients with untreated metastatic EGFR-mutated lung adenocarcinoma. This single-center retrospective, exploratory analysis was performed between January 2015 and December 2019. Among 1350 cases of NSCLC, 470 were EGFR mutant, of which PDL1 expression testing was done in 193 patients who were included in this study. Median age was 60years (range 24-87years). A total of 116 patients (60.1%) had inframe deletion in exon19, 52 (26.9%) had L858R, and 25 (13%) had uncommon mutations. The number of patients with PDL1 tumour proportion score (TPS) < 1% was 109 (56.5%); 1-49%, 57 (29.5%); and ≥ 50%, 27 (14%). Comparing clinical characteristics among various PDL1 groups, there were no statistically significant correlations obtained. However, patients with PDL1 > 50% were smokers, and showed a trend for higher disease burden at diagnosis. Median PFS of PDL1 < 1% was 10.14months, compared to 9.4months in the PDL1 > 1% group; however, the values did not reach statistical significance. The current study was an exploratory retrospective study; however, the results add to the growing body of evidence that PDL1 expression in EGFR-mutated NSCLC does not have any prognostic significance. Also the efficacy of EGFR TKIs is not influenced by variations in PDL1 TPS.

Impact of HER2 expression on EGFR-TKI treatment outcomes in lung tumors harboring EGFR mutations: A HER2-CS study subset analysis

ObjectivesEpidermal growth factor receptor (EGFR)-tyrosine kinase inhibitors (TKIs) are standard treatment for EGFR-mutated non-small-cell lung carcinoma (NSCLC); however, a biomarker to predict their efficacy has not been established. Although human epidermal growth factor receptor-2 (HER2) aberrations constitute a potential mechanism for acquired resistance to EGFR-TKIs, the impact of HER2 on EGFR-TKI treatment outcomes has not been systematically evaluated. In this post-hoc subgroup study, we examined the impact of HER2 on the effect of EGFR-TKIs in patients with NSCLC harboring EGFR mutations. Materials and MethodsOf 1126 patients with NSCLC enrolled into a prospective cohort study (HER2-CS study), we analyzed data of 356 (32 %) patients with EGFR-mutant tumors. HER2 protein expression levels were determined by immunohistochemistry (IHC) with the gastric cancer criteria. Patients were divided either to an HER2-P group (HER2-IHC2+/3+) or an HER2-N group (HER2-IHC0/1+). We primarily assessed differences in the time-to-treatment failure (TTF) of EGFR-TKI between the groups. ResultsThe HER2 scoring was as follows: IHC0 (n = 76, 21 %), IHC1+ (n = 199, 56 %), IHC2+ (n = 72, 20 %), and IHC3+ (n = 9, 3 %). The patients’ demographics were similar in the HER2-P and HER2-N groups. The HER2-P group showed a significantly shorter EGFR-TKI TTF than the HER2-N group (hazard ratio [HR]: 1.657, 95 % confidence interval [CI]: 1.076–2.552; median: 13.3 vs. 19.1 months). The magnitude of the negative impact of TTF was especially dependent on performance status (PS). HER2 expression significantly deteriorated the TTF in the subgroup with PS 2 (HR: 5.497, 95 % CI: 1.510–20.02), but not in that with better PS (HR: 1.437, 95 % CI: 0.899–2.298) (pinteraction = 0.015). ConclusionIn the current cohort, HER2 protein expression in EGFR-mutant NSCLC may have a negative impact on the effect of EGFR-TKIs, the effect of which was PS dependent.

Endothelin-1-Mediated Drug Resistance in EGFR-Mutant Non-Small Cell Lung Carcinoma.

Progression on therapy in non-small cell lung carcinoma (NSCLC) is often evaluated radiographically, however, image-based evaluation of said therapies may not distinguish disease progression due to intrinsic tumor drug resistance or inefficient tumor penetration of the drugs. Here we report that the inhibition of mutated EGFR promotes the secretion of a potent vasoconstrictor, endothelin-1 (EDN1), which continues to increase as the cells become resistant with a mesenchymal phenotype. As EDN1 and its receptor (EDNR) is linked to cancer progression, EDNR-antagonists have been evaluated in several clinical trials with disappointing results. These trials were based on a hypothesis that the EDN1-EDNR axis activates the MAPK-ERK signaling pathway that is vital to the cancer cell survival; the trials were not designed to evaluate the impact of tumor-derived EDN1 in modifying tumor microenvironment or contributing to drug resistance. Ectopic overexpression of EDN1 in cells with mutated EGFR resulted in poor drug delivery and retarded growth in vivo but not in vitro. Intratumoral injection of recombinant EDN significantly reduced blood flow and subsequent gefitinib accumulation in xenografted EGFR-mutant tumors. Furthermore, depletion of EDN1 or the use of endothelin receptor inhibitors bosentan and ambrisentan improved drug penetration into tumors and restored blood flow in tumor-associated vasculature. Correlatively, these results describe a simplistic endogenous yet previously unrealized resistance mechanism inherent to a subset of EGFR-mutant NSCLC to attenuate tyrosine kinase inhibitor delivery to the tumors by limiting drug-carrying blood flow and the drug concentration in tumors. SIGNIFICANCE: EDNR antagonists can be repurposed to improve drug delivery in VEGFA-secreting tumors, which normally respond to TKI treatment by secreting EDN1, promoting vasoconstriction, and limiting blood and drug delivery.

Retrospective analysis of osimertinib re-challenge after osimertinib-induced interstitial lung disease in patients with EGFR-mutant non-small cell lung carcinoma.

Osimertinib is a third-generation epidermal growth factor receptor (EGFR) tyrosine kinase inhibitor (TKI) that has exhibited efficacy in patients with EGFR-mutant non-small cell lung cancer (NSCLC). Interstitial lung disease (ILD) is a fatal adverse event of osimertinib treatment, and it requires treatment discontinuation. There are few reports regarding the safety and efficacy of osimertinib re-challenge in patients who experienced osimertinib-induced ILD. This retrospective study assessed this treatment option. We retrospectively collected data for patients treated with osimertinib who developed ILD at Shizuoka Cancer Center from April 2016 to March 2020. ILD was diagnosed by two doctors based on imaging tests and blood tests to exclude other causes. Among 215 patients treated with osimertinib, 28 developed ILD. The median age of patients with ILD was 69.5years (range, 39.0-80.0). In addition, 29% of patients were men, and 46% had a history of smoking. Eleven patients were re-administered EGFR TKIs, including eight patients treated with osimertinib and three patients treated with alternative EGFR TKIs. Among patients re-challenged with osimertinib, none who previously experienced grade 1 ILD exhibited ILD relapse, even with the same osimertinib dose and without the concurrent administration of systemic steroids. Meanwhile, one of the four patients who previously exhibited grade 2 ILD experienced despite a dose reduction for osimertinib and systemic steroid administration. For patients with EGFR-mutant NSCLC who experience grade 1 ILD during osimertinib therapy, osimertinib re-challenge may be suitable when no other treatments are available.

23P DAB2IP inhibits metastasis in NSCLC by governing cell-matrix and cell-cell adhesions

Metastasis is a critical factor for the high mortality in Non-small-cell lung carcinoma (NSCLC), but the mechanism is still not completely understood. DAB2IP, as a Ras GTPase-activating protein and novel scaffold protein, is involved in the progression of various cancers. Previously, it was reported that DAB2IP methylation status in circulating DNA could predict response to erlotinib in EGFR-mutated NSCLC patients. However, the role of DAB2IP in NSCLC has rarely been investigated.

Propensity score analysis of overall survival between first- and second-generation EGFR-TKIs using real-world data.

We constructed a data set of EGFR‐mutant non–small‐cell lung carcinoma (NSCLC) patients, and compared the overall survival of first‐generation (1G), and second‐generation (2G) EGFR‐tyrosine kinase inhibitors (TKIs) in clinical practice using a propensity score. We reviewed the clinical data of consecutive EGFR‐mutated NSCLC patients who received EGFR‐TKI therapy between January 2008 and August 2017 at 11 institutions in Japan. The primary endpoint was overall survival (OS). When comparing OS between 1G and 2G EGFR‐TKIs, propensity score analyses were performed using 2 methods: matching and inverse probability of treatment weighting (IPTW). (Clinical Trial information: UMIN000030121) In total, 1400 patients from 11 institutions were enrolled in this study, and the data from the 1366 patients who received only EGFR‐TKI therapy were analyzed (gefitinib [GEF], N = 732; erlotinib [ERL], N = 416; afatinib, N = 218). Median OS times (months [95%CI]) were 29.7 [27.5‐33.5] in the 1G group (gefitinib, 32.0 [28.1‐35.8]; erlotinib, 27.5 [23.9‐31.7]), and 38.6 [32.2‐NR] in the 2G group (afatinib), respectively. The trend of longer OS for afatinib against 1G EGFR‐TKIs remained, even after adjusted by propensity score. (unadjusted, hazard ratio [HR] 0.676, P = .0023; adjusted by IPTW, HR 0.685 P < .0001; adjusted by matching, HR 0.725, P = .0418). Exploratory analysis showed that OS using the 2G EGFR‐TKI was superior to that of the 1G EGFR‐TKIs, suggesting the potential of sequential therapy of 2G EGFR‐TKI followed by osimertinib. (HR 0.419, P = .0519) Real‐world data analysis using 1354 data records, using propensity scoring, indicated that 2G EGFR‐TKI had a trend of longer OS compared with 1G EGFR‐TKIs.

Clinical Features of Patients with an Epidermal Growth Factor Receptor T790M Mutation Detected in Circulating Tumor DNA

Background: Osimertinib, a third-generation epidermal growth factor receptor (EGFR)-tyrosine kinase inhibitor (TKI), is effective against EGFR-mutated non-small cell lung carcinoma resistant to first- or second-generation EGFR-TKIs in patients in whom an EGFR T790M mutation has been detected. Detection of the T790M mutation using circulating tumor DNA (ctDNA) is less invasive than a tissue re-biopsy, including a transbronchial lung biopsy; however, the prognostic implications of the T790M mutation in ctDNA have not been fully elucidated. Methods: We retrospectively reviewed the clinical features of non-small cell lung carcinoma patients in whom an EGFR T790M mutation had been detected at our hospital and assessed the clinical outcomes of osimertinib for these patients in terms of detection sites. Results: An EGFR T790M mutation was detected in 32 non-small cell lung carcinoma patients, of whom 21 (65.6%) underwent osimertinib treatment after detection of the mutation. The mutation was detected using plasma samples in 10 patients (47.6%; liquid biopsy group), while it was detected using tissue samples in 11 patients (52.4%; tissue biopsy group). Liver and bone metastases were more frequently observed in patients in the liquid biopsy group than in the tissue biopsy group (30.0 vs. 0% and 60.0 vs. 18.2%, respectively). The median progression-free survival time was significantly shorter in the liquid biopsy group (132.0 days) than in the tissue biopsy group (682.0 days). The median overall survival time in the liquid biopsy group was 376.0 days, whereas that in the tissue biopsy group was not reached during our observation period. Conclusions: Non-small cell lung carcinoma patients in whom an EGFR T790M mutation was detected in plasma samples demonstrated a poorer response to osimertinib than those in whom the mutation was detected in tissue specimens.

EGFR exon 20 insertion mutations and response to osimertinib in non-small-cell lung cancer

BackgroundEpidermal growth factor receptor exon 20 insertion (EGFRex20ins) mutations represent approximately 4–12% of EGFR mutations and are generally refractory to the 1st and 2nd generation EGFR tyrosine kinase inhibitors (TKIs). Development of effective therapies for patients with EGFRex20ins mutant non-small-cell lung carcinoma (NSCLC) represents a great unmet need. Preclinical models have shown that osimertinib is active in NSCLC harboring EGFRex20ins, while the antitumor activity of osimertinib remains to be evaluated in patients with EGFRex20ins mutations.MethodsTumor genotyping was performed in 2316 Chinese NSCLC cases with targeted next generation sequencing (NGS) covering the whole exons of EGFR gene. The frequency and genetic characteristics of EGFRexon20ins mutations were analyzed. Furthermore, six patients with specific EGFRexon20ins mutations and receiving osimertinib 80 mg once daily were retrospectively included to assess the antitumor activity and safety of monotherapy osimertinib.ResultsEGFRex20ins mutations were identified in 4.8% (53/1095) of EGFR mutant NSCLC and 2.3% (53/2316) of all NSCLC cases. The most frequently identified EGFRexon20ins is A767_V769dup (17/53,32.1%). We found that the genetic characteristics of EGFRex20ins mutations in Chinese patients with NSCLC were comparable to those reported in Caucasian patients. Four patients with osimertinib therapy achieved partial response and the rest stable disease. Median progression free survival (PFS) was 6.2 months (95% confidence interval 5.0–12.9 months; range 4.9–14.6 months). The most common adverse events (AEs) were diarrhea (2/6), pruritis (2/6), stomatitis (1/6) and nausea (1/6). No grade 3 or more AEs were documented.ConclusionsThis study revealed that the genetic characteristics of EGFRex20ins mutations in Chinese patients with NSCLC were comparable to those reported in Caucasian patients. Furthermore, our study firstly demonstrated promising antitumor activity of osimertinib in certain EGFRex20ins mutant advanced NSCLC patients, indicating that osimertinib treatment for EGFRex20ins positive patients deserves further study.

Structure-based inhibitory peptide design targeting peptide-substrate binding site in EGFR tyrosine kinase.

EGFR (epidermal growth factor receptor) plays the critical roles in the vital cell activities, proliferation, differentiation, migration and survival in response to polypeptide growth factor ligands. Aberrant activation of this receptor has been demonstrated in many human cancers, particularly in non-small cell lung carcinoma (NSCLC). L858R point mutation is the most common oncogenic mutation in EGFR tyrosine kinase domain in patients with EGFR-mutated NSCLC. A feedback inhibitor of EGFR is MIG6 molecule which binds peptide-substrate binding site of the receptor and leads to degradation of activated EGFR. In this in silico study, the peptide-substrate binding site of EGFRL858R mutant has been targeted to inhibit it using molecular docking, MD simulation and MM-PBSA method. Finally, physicochemical properties of the designed peptides have been evaluated. A peptide library was provided composed of 31 peptides which were designed based on the MIG6 structure. The results indicated that, two peptides were able to inhibit EGFRL858R mutant selectively. This computational study could be helpful in designing novel inhibitory peptides to inhibit oncogenic EGFR mutants which do not respond to available EGFR TKIs.

Impact of HER2 aberrations on EGFR-TKI treatment outcomes in lung tumors harboring EGFR mutations: A HER2-CS STUDY subset analysis.

9056 Background: Epidermal growth factor receptor (EGFR) tyrosine kinase inhibitors (TKIs) are a key treatment for EGFR-mutated non-small-cell lung carcinoma (NSCLC). To date, a biomarker to predict whether NSCLC will exhibit a short- or long-term response to first- or second-generation EGFR-TKIs has not been established for clinical use. Human epidermal growth factor receptor-2 (HER2) aberrations are mechanisms for acquired resistance to EGFR-TKIs; however, their impact on EGFR-TKI therapy outcomes in EGFR-mutant NSCLC has not yet been systematically evaluated. Methods: Patients with advanced NSCLC were prospectively registered from more than 35 institutes (HER2-CS STUDY UMIN 000017003). EGFR mutations or anaplastic lymphoma kinase gene translocations were assessed at each institution using a commercially approved test. HER2 protein expression levels were determined by immunohistochemistry (IHC) using the Ventana I-VIEW PATHWAY anti-HER-2/neu (4B5). The IHC status scoring system applied to gastric cancer was used. Results: Of 1,126 screened patients with NSCLC, 354 (31.8%) had EGFR-mutated tumors, and the HER2 protein statuses were as follows: IHC0 (n = 71, 26%), IHC1+ (n = 148, 53%), IHC2+ (n = 51, 18%), and IHC3+ (n = 7, 3%). The patients’ demographics were almost identical in those with lung tumors harboring EGFR mutations and HER2-IHC2+/3+ (group P) or EGFR mutations and HER2-IHC0/1 (group N). The EGFR-TKI response rates were not different between these groups (Table). However, group P showed significantly shorter time to EGFR-TKI treatment failure than group N (median 19.1 vs. 13.3 months; log rank p = 0.038). Conclusions: These data from a large prospective cohort show that HER2 protein expression in EGFR-mutant NSCLC may have a negative impact on the effect of EGFR-TKIs. A clinical trial of EGFR/HER2-TKIs (e.g., afatinib) is warranted for this population. [Table: see text]

The expression of circulating miR-504 in plasma is associated with EGFR mutation status in non-small-cell lung carcinoma patients

MicroRNAs (miRNAs), key regulators of gene expression at the post-transcriptional level, are grossly misregulated in some human cancers, including non-small-cell lung carcinoma (NSCLC). The aberrant expression of specific miRNAs results in the abnormal regulation of key components of signalling pathways in tumour cells. MiRNA levels and the activity of the gene targets, including oncogenes and tumour suppressors, produce feedback that changes miRNA expression levels and indicates the cell’s genetic activity. In this study, we measured the expression of five circulating miRNAs (miR-195, miR-504, miR-122, miR-10b and miR-21) and evaluated their association with EPIDERMAL GROWTH FACTOR RECEPTOR (EGFR) mutation status in 66 NSCLC patients. Moreover, we examined the discriminative power of circulating miRNAs for EGFR mutant‐positive and -negative NSCLC patients using two different data normalisation approaches. We extracted total RNA from the plasma of 66 non-squamous NSCLC patients (31 of whom had tumours with EGFR mutations) and measured circulating miRNA levels using quantitative reverse transcription polymerase chain reaction (RT-qPCR). The miRNA expression levels were normalised using two endogenous controls: miR-191 and miR-16. We found significant associations between the expression of circulating miR-504 and EGFR-activating mutations in NSCLC patients regardless of the normalisation approach used (p = 0.0072 and 0.0236 for miR-16 and miR-191 normalisation, respectively). The greatest discriminative power of circulating miR-504 was observed in patients with EGFR exon 19 deletions versus wild-type EGFR normalised to miR-191 (area under the curve (AUC) = 0.81, p < 0.0001). Interestingly, circulating miR-504 levels were significantly reduced in the v-Ki-ras2 Kirsten rat sarcoma viral oncogene homolog (KRAS)-mutated subgroup compared to EGFR-mutated patients (p < 0.0030) and those with EGFR/KRAS wild-type tumours (p < 0.0359). Our study demonstrated the feasibility and potential diagnostic value of plasma miR-504 expression analysis to distinguish between EGFR-mutated and wild-type NSCLC patients. However, quality control and normalisation strategies are very important and have a major impact on the outcomes of circulating miRNA analyses.

144PD Leptomeningeal metastases in EGFR-mutated non-small cell lung carcinoma: Management after tyrosine kinase inhibitors

Background: Leptomeningeal metastases (LM) in non-small-cell lung carcinoma (NSCLC) are associated with poor outcome. Tyrosine kinase inhibitors (TKIs) are active in LM+ EGFR mutated (EGFRm) patients (pts), but optimal patient's management after failure of TKIs is unknown. Methods: We included consecutive pts with EGFRm NSCLC who had LM progression during first-line EGFR TKI, defined as diagnosis of LM during TKI treatment or progression of known LM after first-line TKI, treated in our institution. Clinical and pathological data were retrospectively collected. We evaluated overall survival (OS), progression-free survival (PFS), clinical response rate (CRR), and disease control rate (DCR) defined as clinical response or stable disease >2 months. Results: We included 66 pts treated between Apr. 2003 and Sept. 2016, with a median age of 54 years [26–79]; 51 (77%) were females; 56 (85%) non-smokers. Twenty-three tumors (35%) had exon 19 deletion, 23 (35%) L858R exon 21 mutation, 10 (15%) T790M mutation. Median number of previous lines was 2 [1–7], and 19 pts (29%) had additional intrathecal treatment. 2nd line TKI was given to 36 pts (55%): 19 (53%) received erlotinib, 10 (28%) high dose (HD) erlotinib (300 mg daily), 3 osimertinib, 4 other 1st/2nd generation TKI (3 gefitinib, 1 afatinib). Median PFS and OS from LM progression were 3 months (m) [CI95% 2–3] and 7 m [CI95% 3–16], respectively. CRR and DCR for 2nd-line TKI were 43% and 77%. Nine pts (25%) were alive at 10 m (6 erlotinib, 1 HD erlotinib, 2 osimertinib). Median OS for erlotinib, HD erlotinib, osimertinib and other 1st/2nd generation TKI were 8 m (CI 95% 7–16), 3 m (CI 95% 2-not reached (NR)), NR (CI 95% NR-NR), and 2.5 m (CI 95% 0-NR), respectively. Patients treated with erlotinib, of whom 79% received prior afatinib or gefitinib, had better OS compared to patients treated with other 1st/2nd generation TKI (8 m vs. 2.5 m, P = 0.04). CRR and DCR in patients with HD erlotinib were 40% and 60%, respectively, of whom 80% received prior erlotinib. Conclusions: 2nd-line TKI can increase survival in LM+ EGFRm NSCLC previously treated with TKI. Sequential erlotinib after prior gefitinib or afatinib seems to be a suitable strategy. Increasing erlotinib dose has demonstrated clinical benefit. Legal entity responsible for the study: Gustave Roussy Funding: Has not received any funding Disclosure: All authors have declared no conflicts of interest.