Epidermal Growth Factor Receptor T790 Research Articles

EGFR-T790M mutation associated with acquired resistance to first-generation EGFR tyrosine kinase inhibitors in Vietnamese Non-Small-Cell Lung Cancer patients

Background: non-small cell lung cancer (NSCLC) patients who had epidermal growth factor receptor (EGFR) mutations sensitive to EGFR tyrosine kinase inhibitors (TKIs) had a high response rate to target therapies. Epidermal growth factor receptor (EGFR) T790M mutation is the most common mechanism of acquired resistance to first-generation EGFR TKIs. Objective: The aim of this study was to analyze the incidence of EGFR T790 mutation, the progression-free survival (PFS) in the patients who progress on the first‑ generation EGFR‑TKIs. This study also investigates the correlation between T790M mutation and clinical, subclinical features, progression-free survival of NSCLC Vietnamese patients.
 Patients and methods: We analyzed 66 NSCLC patients who had acquired resistance to first-generation EGFR-TKIs. The clinical data, PFS and the mechanism of acquired resistance were obtained. The Kaplan-Meier method and the log-rank test were used to analyze the PFS and compare between subgroups of patient characteristics. The correlations between the patient’s characteristics and EGFR-T790M mutation status were analyzed by Chi-square and Fisher’s exact tests.
 Results: At the progressive period, EGFR T790M mutation was detected in 54.5% of patients. The median PFS were 14.48 ± 3.9 months (range: 8- 26 months). Patients who were older than 60 years old or had comorbidities had significantly shorter PFS than the subgroups without (P≤0.05). The age, gender, smoking status, comorbidities, pathological features were not significantly correlated with the development of EGFR-T790M (P > 0.05). The average PFS was not significantly different between the EGFR-T790M group and the non-EGFR-T790M group (P=0.642).
 Conclusion: In our cohort study, more than half of all patients had T790M mutation after being treated with first-generation EGFR TKIs. Age and comorbidities were associated with PFS but the EGFR-T790M mutation was not correlated with PFS.

Osimertinib 80 mg EOD? Does this work?

Osimertinib is a third-generation thyroxine kinase inhibitor (TKI) used in treating advanced non-small cell lung cancer (NSCLC) patients with epidermal growth factor receptor (EGFR) mutation. Osimertinib is used as a second line treatment for patients who develop EGFR T790 M resistance mutation rather than first line due to financial constraints. We present a case of a 60-year-old Chinese gentleman who diagnosed as stage 4 adenocarcinoma with EGFR Exon 19 deletion. His disease progressed after a year of treatment with afatinib. His plasma T790 M was negative and due to delay in tissue biopsy, he was empirically started on osimertinib. However, in view of financial concerns, he opted a dose reduction of 80 mg every alternate day rather than the conventional dose of 80 mg daily. Serial CT Thorax showed partial response based on RECIST 1.1 criteria and he has 9 months of progression free survival. This case report shows that Osimertinib in reduced dose may achieve good partial response and progression free survival in patients.

Rational design of EGFR dimerization-disrupting peptides: A new strategy to combat drug resistance in targeted lung cancer therapy

Although a variety of tyrosine kinase inhibitors (TKIs) have been developed to target human epidermal growth factor receptor (EGFR) for lung cancer therapy, many patients treated with first-line small-molecule TKIs are clinically observed to eventually establish drug-resistant mutations T790 M and C797S around kinase active site, which play a primary role in development of acquired drug resistance to first-generation reversible and second-generation irreversible TKIs, respectively. Here, instead of developing small-molecule drugs to directly target the active site, we attempt to derive self-inhibitory peptides (SIPs) from the EGFR:EGFR asymmetric dimerization interface, where is separated from kinase active site and has a relatively low conservation as compared to the active site. It is found that the dimerization is a typical peptide-mediated protein interaction, where the first EGFR N-lobe adopts an N-terminal binding sequence (nBS) to interact with the dimerization interface of second EGFR C-lobe. A core binding sequence (nCBS, 676NQALLRILKE68) is identified in the nBS region as hotspot segment, which is then rationally optimized to generate a number of SIPs. Consequently, three designed SIPs are determined as promising candidates; they have high affinity to EGFR kinase domain, strong competitive potency with native nBS peptide for the dimerization interface, and effective cytotoxicity on human lung cancer cell lines. It is also demonstrated that these peptides are insensitive to drug-resistant EGFR T790 M/C797S mutation at molecular and cellular levels, and exhibit a good selectivity for EGFR over HER2 at molecular level.

EGFR-TKI acquired resistance in lung cancers harboring EGFR mutations in immunocompetent C57BL/6J mice

ObjectivesLung cancers harboring epidermal growth factor receptor (EGFR) mutations inevitably develop resistance to EGFR tyrosine-kinase inhibitors (EGFR-TKIs). Therefore, we sought to establish clinically relevant lung-cancer mouse models to achieve deep remission of cancers. Materials and methodsWe previously established two transgenic lung-cancer mouse models harboring human EGFR exon 21 L858R substitution (hLR) and mouse Egfr exon 19 deletion (mDEL) in the C57BL/6 J background. Lung tumors from these two transgenic mouse strains were transplanted subcutaneously into BALB/c-nunu mice or C57BL/6 J mice. ResultsThe transplanted tumors developed the ability to grow on the subcutaneous tissue, peritoneum, or lung of C57BL/6 J mice. While hLR tumors could grow only in C57BL/6 J mice carrying the transgene, mDEL tumors could grow in wild-type C57BL/6 J mice. The tumors maintained EGFR-dependency, and, thus, the EGFR-TKI gefitinib inhibited tumor growth; however, similar to human lung cancers, hLR and mDEL tumors acquired resistance in 60 and 200 days, respectively, following gefitinib administration. Secondary EGFR T790 M mutation in hLR tumors and secondary Egfr T792I mutation in mDEL tumors developed; however, no MET activation was detected. Accordingly, the third-generation EGFR-TKI osimertinib effectively inhibited gefitinib-resistant tumors in vivo. Furthermore, gefitinib-resistant tumors developed resistance to osimertinib in 100 days. ConclusionThese syngeneic lung-cancer mouse models harboring EGFR mutations are suitable for studying the drug-resistance mechanisms and the role of the tumor microenvironment. Further investigation with these mouse models is warranted for developing next-generation treatment strategies for lung cancer.

Afatinib helped overcome subsequent resistance to osimertinib in a patient with NSCLC having leptomeningeal metastasis baring acquired EGFR L718Q mutation: a case report

BackgroundThe epidermal growth factor receptor (EGFR)-mutated advanced non-small-cell lung cancer has been successfully treated with tyrosine kinase inhibitors (TKIs). Acquired resistance becomes a tough issue when patients fail to respond to the third-generation TKI osimertinib. This study aimed to report a case baring acquired EGFR L858R/L718Q mutation in the central nervous system induced by osimertinib, which was successfully overcome using afatinib.Case presentationA 65-year-old female patient was diagnosed with stage IV non-small-cell lung adenocarcinoma with synchronic brain metastasis in February 2015. Before and during treatment, 416 tumor-related genes were monitored dynamically by liquid biopsies using next-generation sequencing, and the treatment strategy was decided according to the gene status. At baseline, an EGFR L858R mutation in exon 21 was detected, so treatment with icotinib was started. After 8 months, she experienced disease progression with leptomeningeal metastasis and switched to osimertinib based on an acquired EGFR T790 M mutation. After 9 months, her disease progressed and an EGFR L718Q mutation was found in the cerebrospinal fluid. The patient was then challenged with afatinib, and her disease was under control for 4 months. In January 2017, the patient passed away, with an overall survival time of 23 months, 15 months after leptomeningeal metastasis.ConclusionThe acquired EGFR L718Q mutation in the cerebrospinal fluid resulted in subsequent resistance to osimertinib and could be partly overcome using afatinib, indicating a promising treatment option in the clinic.

Safety, tolerability, and anti-tumor activity of olmutinib in non-small cell lung cancer with T790M mutation: A single arm, open label, phase 1/2 trial

ObjectivesThe aim of this phase 1/2 study was to evaluate the safety, tolerability, pharmacokinetics and antitumor activity of olmutinib in patients with epidermal growth factor receptor (EGFR)-mutated non-small cell lung cancer (NSCLC) who had failed ≥ 1 previous line of EGFR-tyrosine kinase inhibitor (TKI) therapy. Materials and methodsPhase 1 consisted of dose-escalation and four dose-expansion parts (1: olmutinib 300 mg once daily; 2A: 800 mg once daily [EGFR T790 M mutation-positive patients]; 2B: 500 mg twice daily [EGFR T790 M mutation-positive]; 3: 800 mg once daily [EGFR T790 M mutation-negative]). In phase 2, EGFR T790 M mutation-positive patients received olmutinib 800 mg once daily. Data from expansion part 2A and phase 2 were integrated (`pooled phase 2′). Each olmutinib cycle was 21 days. Outcomes included: tumor response, treatment-emergent adverse events (TEAEs), pharmacokinetic parameters. ResultsOverall, 272 patients received at least one olmutinib dose: dose-escalation (n = 66), expansion parts (n = 165), phase 2 (n = 41). In pooled phase 2, the overall objective response rate, confirmed by independent review, was 55.1% (38/69 evaluable patients; 95% CI, 42.6–67.1). All responses were partial responses; 23 patients had stable disease. Estimated median progression-free survival was 6.9 (95% CI, 5.6–9.7) months; estimated median overall survival was not reached. The most frequent treatment-related AEs were diarrhea (59.2% of patients), pruritus (42.1%), rash (40.8%), and nausea (39.5%). ConclusionOlmutinib showed effective clinical activity with a manageable safety profile, indicating therapeutic potential for T790M-positive NSCLC patients who have failed ≥ 1 previous line of EGFR-TKI therapy.

P3.01-60 A Novel MET D1246H Mutation After Progression of EGFR-TKI/MET Inhibitor Combined Therapy in a NSCLC Patient with Acquired MET Amplification

MET amplification was the second common acquired resistance mechanism to epidermal growth factor receptor (EGFR) tyrosine kinase inhibitor (TKI) in patients with advanced non-small cell lung cancer (NSCLC). It may be benefited by combinations of EGFR TKIs and the MET inhibitor. However, the acquired resistance mechanism to this combination therapy remains to be identified. A patient with advanced lung adenocarcinoma harboring both EGFR L858R mutation and acquired MET amplification, progressed after the combination of MET inhibitor gefitinib and EGFR-TKI crizotinib. The next generation sequencing (NGS) based circulating tumor DNA (ctDNA) assay was performed. Results were applied to discover a novel mutation after resistance to target therapy. A 52-year-old Chinese never-smoking woman with EGFR L858R mutant adenocarcinoma had systemic progression after gefitinib, pemetrexed/platinum-pemetrexed maintenance, and SBRT local progressed lung metastasis. The NGS-based ctDNA analysis revealed that the MET amplification was found besides continually present EGFR L858R mutation. The patient started treatment with crizotinib (250mg Bid) and gefitinib (250mg/d). The NGS was performed after progression of this combined therapy. It revealed two novel mutations of MET D1246H (MAF 0.9%) and EGFR T790M mutation (MAF 0.2%), in addition to the initial presence of EGFR L858R mutation (MAF 9.8%) and MET amplification (LR 6.7). The patient started to receive osimertinib (80mg/d) and cabozantinib (20mg/d and later increased to 40mg/d). The patient tolerated this combination well while the symptoms did not relief. After 8 weeks, the re-scan CT showed pulmonary lesions progressed. The NGS-based ctDNA assay performed again and it showed that L858R mutation (MAF 11.4%) and MET amplification (LR 4.9) presented while the EGFR T790 mutation and MET D1246H disappeared. Then the patient received osimertinib (80mg/d) and crizotinib (250mg Bid). The patient felt symptoms improved greatly after 1 week’s administration and CT scan after 2 months showed good response. However, one more month later, the patient felt deteriorative symptoms of dyspnea and chest X-ray showed increasing pleural effusion, progressing pulmonary lesions. The NGS-based ctDNA assay at that time revealed that MET D1246H (MAF 14.4%) appeared again, in addition to the initial presence of EGFR L858R mutation (MAF 22.4%) and MET amplification (LR 8.2) while the EGFR T790 mutation was not existed. However, the patient died because of respiratory failure. MET mutations might be a potential acquired resistance mechanism after progression during EGFR-TKI /MET inhibitor combined therapy in advanced NSCLC patient with primary EGFR mutation and secondary acquired MET amplification.

Penetration of the blood–brain barrier by avitinib and its control of intra/extra-cranial disease in non-small cell lung cancer harboring the T790M mutation

BackgroundAvitinib is an oral, potent, irreversible epidermal growth factor receptor (EGFR) tyrosine kinase inhibitor selective for the EGFR T790 M mutation. We report the safety, intra-/extracranial efficacy, and the blood–brain barrier (BBB) penetration rate of avitinib (NCT02330367). MethodsNon-small cell lung cancer (NSCLC) patients with the EGFR T790 M mutation were orally administered avitinib (150–300 mg) twice daily for cycles of 28 continuous days. Blood and cerebrospinal fluid samples (2 ml each) were collected on day 29 in available patients with brain metastases, and the tumor response was assessed. ResultsSixteen NSCLC patients were included, of whom nine (60.0%) achieved a partial response, and five (33.3%) achieved stable disease. Median progression-free survival (PFS) and overall survival were 247 days (95% confidence interval (CI): 154.8–339.2) and 536 days (95%CI: 363.6–708.4), respectively. The median intracranial PFS of seven brain metastases patients was 142 days (95% CI 31.1–252.9). Blood and cerebrospinal fluid analysis of five brain metastases patients showed the BBB penetration rate to be 0.046%–0.146%. The most frequent adverse events were mild and reversible hepatic transaminases elevating (10/16, 62.5%) and diarrhea (4/16, 25.0%). ConclusionsAvitinib is well tolerated and efficacious in T790M-positive patients. Its penetrability to the BBB is weak, but it showed good control of asymptomatic brain metastases. Further studies are proceeding.

Discovery of novel 2,4-diarylaminopyrimidine derivatives as potent and selective epidermal growth factor receptor (EGFR) inhibitors against L858R/T790M resistance mutation

A series of novel 2,4-diarylaminopyrimidine derivatives of AZD9291 were discovered as L858R/T790M mutant selective epidermal growth factor receptor (EGFR) inhibitors. The majority of these compounds exhibited moderate to excellent EGFR T790 M/L858R inhibitory activities and comparable anti-proliferative activities against double mutant over-expressed NCI-H1975 cells to that of AZD9291. The most promising compounds 8a displayed an IC50 of 4.1 nM against EGFR L858R/T790M mutants. 8a also showed excellent cytotoxic effect against NCI-H1975 cells with an IC50 of 59 nM and 100-fold selectivity over wide-type EGFR over-expressed A431 cells. Compound 8a significantly inhibited tumor growth in NCI-H1975 xenograft models at a non-toxic dose. Docking study performed for 8a with ATP binding site of EGFR-TK showed the similar binding mode to that of AZD9291. All these results suggested that compound 8a was a potential mutant-selective EGFR inhibitor.

Design and synthesis of quinazolinones as EGFR inhibitors to overcome EGFR resistance obstacle

The epidermal growth factor receptor (EGFR) T790M mutant is found in about 50% of clinically acquired resistance to gefitinib among patients with non-small cell lung cancer (NSCLC). New derivatives of 4(3H)-quinazolinones were synthesized and evaluated for their inhibitory activity against NSCLC. The results of the study demonstrated that compound 79, 7-chloro-3-(5-(4-methoxyphenyl)-1,3,4-thiadiazol-2-yl)-2-phenylquinazolin-4(3H)-one was found to be the most potent compounds of the series with IC50 value of 0.031μM against mutant T790M/L858R EGFR. Compounds 15, 51, 73, 75, 78, 79 and 96 were less potent against A549 (WT EGFR and k-Ras mutation) and HT-29 (non-special gene type) cells, showing a high safety index. The obtained results showed that compounds 15, 51, 73, 75, 78, 79 and 96 could be the promising template to overcome drug resistance mediated by the EGFR T790 Mutant.

Molecular Targeting of Growth Factor Receptor Signaling in Radiation Oncology.

Ionizing radiation has been shown to activate and interact with multiple growth factor receptor pathways that can influence tumor response to therapy. Among these receptor interactions, the epidermal growth factor receptor (EGFR) has been the most extensively studied with mature clinical applications during the last decade. The combination of radiation and EGFR-targeting agents using either monoclonal antibody (mAb) or small-molecule tyrosine kinase inhibitor (TKI) offers a promising approach to improve tumor control compared to radiation alone. Several underlying mechanisms have been identified that contribute to improved anti-tumor capacity after combined treatment. These include effects on cell cycle distribution, apoptosis, tumor cell repopulation, DNA damage/repair, and impact on tumor vasculature. However, as with virtually all cancer drugs, patients who initially respond to EGFR-targeted agents may eventually develop resistance and manifest cancer progression. Several potential mechanisms of resistance have been identified including mutations in EGFR and downstream signaling molecules, and activation of alternative member-bound tyrosine kinase receptors that bypass the inhibition of EGFR signaling. Several strategies to overcome the resistance are currently being explored in preclinical and clinical models, including agents that target the EGFR T790M resistance mutation or target multiple EGFR family members, as well as agents that target other receptor tyrosine kinase and downstream signaling sites. In this chapter, we focus primarily on the interaction of radiation with anti-EGFR therapies to summarize this promising approach and highlight newly developing opportunities.

Abstract 5652: Activation of FGF2-FGFR1 pathway in EGFR-mutant lung cancer cell line with long-term gefitinib exposure.

Abstract Many of the patients with non-small cell lung cancer (NSCLC) with sensitive epidermal growth factor receptor (EGFR)-mutation who initially responded well to EGFR-tyrosine kinase inhibitors (TKIs) eventually relapse. In spite of many studies over the last few years to elucidate this mechanism of acquired resistance to EGFR-TKIs, approximately 30% of the mechanisms of acquired resistance are still unknown. Recently autocrine signaling of fibroblast growth factors (FGFs) and their receptors (FGFRs) has been demonstrated in NSCLC cell lines. And several studies suggest that the FGF-FGFR autocrine growth pathway could be an important mechanism for intrinsic resistance to EGFR-TKIs in NSCLC cell lines with wild-type EGFR. But until now, no report has clarified the role of FGF-FGFR pathway in acquired resistance to EGFR-TKIs in NSCLC cell lines with sensitive EGFR mutations. We have established a gefitinib-resistant cell line (PC9 GR), by serial exposure of gefitinib to PC9, an originally gefitinib-sensitive lung cancer cell line (PC9 na). We confirmed that these cell lines did not harbor two well-known EGFR-TKI resistance mechanisms, the second mutation in the EGFR gene itself, EGFR T790 and the amplification of the MET oncogene. We collected total RNA from both PC9 na and PC9 GR and examined mRNA expression profile, by using cDNA microarray analysis. We found the expressions of FGFR1 and FGF2 were increased in PC9 GR compared to in PC9 na. The growth of PC9 GR cells was inhibited either by PD173074 (inhibitors of FGFRs) or knocking down of FGFR1 or FGF2 by siRNA in combination with gefitinib. FACS analysis revealed that the combination treatment with PD173074 and gefitinib induced apoptosis more efficiently in PC9 GR cells compared to gefitinib alone. PC9 na cells and PC9 GR cells did not show any change in the proportion of apoptotic cells after treatment with PD173074 alone. To further investigate how FGF2-FGFR1 pathway affects resistance to gefitinib in these cell lines, the downstream targets of EGFR signaling including the MEK-ERK and PI3K-AKT pathways were examined. In PC9 na cells, the phosphorylation of EGFR, ERK, and AKT was efficiently inhibited by gefitinib alone. On the other hand, in PC9 GR cells, the phosphorylation of ERK and AKT was not efficiently inhibited by gefitinib alone. However, the inhibition of phosphorylation of ERK was completely and AKT was less efficiently rescued by gefitinib and PD173074 combination therapy. In conclusion, these data suggest the activation of FGF2-FGFR1 signaling pathway contributes to the gefitinib resistance in PC9 GR. FGF2-FGFR1 pathway will be a therapeutic target for a subset of NSCLC that acquires EGFR-TKI resistance. Citation Format: Hideki Terai, Kenzo Soejima, Katsuhiko Naoki, Hiroyuki Yasuda, Ryosuke Satomi, Sohei Nakayama, Satoshi Yoda, Shinnosuke Ikemura, Takashi Sato, Kota Ishioka, Daisuke Arai, Keiko Ohgino, Tetsuo Tani, Aoi Kuroda, Junko Hamamoto, Tomoko Betsuyaku. Activation of FGF2-FGFR1 pathway in EGFR-mutant lung cancer cell line with long-term gefitinib exposure. [abstract]. In: Proceedings of the 104th Annual Meeting of the American Association for Cancer Research; 2013 Apr 6-10; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2013;73(8 Suppl):Abstract nr 5652. doi:10.1158/1538-7445.AM2013-5652