EGFR T790M Mutation Research Articles

RLP system: A single-tube two-step approach with dual amplification cascades for rapid identification of EGFR T790M

BackgroundThe detection of cancer gene mutations in biofluids plays a pivotal role in revolutionizing disease diagnosis. The presence of a large background of wild-type sequences poses a challenge to liquid biopsy of tumor mutation genes. Suppressing the detection of wild-type sequences can reduce their interference, however, due to the minimal difference between mutant and wild-type sequences (such as single nucleotide variants differing by only one nucleotide), how to suppress the detection of wild-type sequences to the greatest extent without compromising the sensitivity of mutant sequence detection remains to be explored. SignificanceThe RLP system addresses the incompatibility between RPA and RT-PCR reactions through a physical separation strategy. Besides, due to the remarkable flexibility of locked nucleic acid probes, the RLP system emerges as a potent tool for detecting mutations across diverse genes. It excels in sensitivity and speed, tolerates plasma matrix, and is cost-effective. This bodes well for advancing the field of precision medicine. ResultsThe recombinase-assisted locked nucleic acid (LNA) probe-mediated dual amplification biosensing platform (namely RLP), which combines recombinase polymerase amplification (RPA) and LNA clamp PCR method in one tube, enabling highly sensitive and selective detection of EGFR T790M mutation under the help of well-designed LNA probes. This technique can quantify DNA targets with a limit of detection (LoD) at the single copy level and identify point mutation with mutant allelic fractions as low as 0.007 % in 45 min. Moreover, RLP has the potential for the direct detection of plasma samples without the need for nucleic acid extraction and the cost of a single test is less than 1USD. Furthermore, the RLP system is a cascading dual amplification reaction conducted in a single tube, which eliminates the risk of cross-contamination associated with opening multiple tubes and ensures the reliability of the results.

Droplet Digital PCR as a Molecular Tool for the Detection of the EGFR T790M Mutation in NSCLC Patients with the EGFR Activating Mutations.

Almost 50% of NSCLC patients who initially show a successful response to tyrosine kinase inhibitors targeted therapy (TKI therapy) eventually develop acquired EGFR T790M mutation. The T790M secondary mutation can cause resistance to the targeted therapy and disease relapse. Since this mutation can be present at very low frequencies in liquid biopsy samples, droplet digital PCR (ddPCR), due to its high sensitivity, has opened the possibility for minimally invasive monitoring of the disease during TKI targeted therapy. For this study, a total of 45 plasma samples from NSCLC patients with previously detected EGFR-activating mutations were analyzed. Extracted circulating free DNA was amplified and examined for the presence of T790M mutation using ddPCR technology. For the data analysis, QuantaSoft Software was used. Of 45 tested plasma samples, a total of 14 samples were identified as positive for the T790M mutation. The same samples eventually showed the presence of T790M mutation in FFPE. Droplet digital PCR showed its great advantage in high sensitivity detection of rare allele variants. Our ddPCR assay detected T790M mutant allele in frequencies from 0.1%. The average number of droplets generated by ddPCR was 9571. Monitoring of the T790M mutation has an important role in the examination of the effects of the prescribed TKI therapy. Since monitoring of potential changes during TKI therapy requires repeated sampling, our results showed that ddPCR technology has made it possible to use liquid biopsy as an adequate minimally invasive alternative for single nucleotide polymorphisms (SNP) detection.

Liquid biopsy in clinical outcomes and detection of T790M mutation in metastatic non-small cell lung cancer after progression to EGFR-TKI.

Liquid biopsy (LB) is used to detect epidermal growth factor receptor (EGFR) mutations in non-small cell lung cancer (NSCLC) and has been demonstrated to have prognostic and predictive value. To associate the rates of EGFR and T790M mutations detected by LB during disease progression after first- or second-generation EGFR-TKIs with clinical characteristics and survival outcomes. From January 2018 to December 2021, 295 patients with advanced EGFR mutant (EGFRm) NSCLC treated with first- or second-generation EGFR-TKIs were retrospectively analyzed. LB was collected at the time of progression. The frequency of EGFRT790M mutations, overall survival (OS), and the clinical characteristics associated with LB positivity were determined. The prevalence of EGFRT790M mutation detected using LB was 44%. In patients with negative vs. positive LB, the median OS was 45.0 months vs. 25.0 months (p= 0.0001), respectively. Patients with a T790M mutation receiving osimertinib had a median OS of 44 months (95% CI [33.05-54.99]). Clinical characteristics associated with positive LB at progression extra-thoracic involvement, > 3 metastatic sites, and bone metastases. Our findings showed that LB positivity was associated with worse survival outcomes and specific clinical characteristics. This study also confirmed the feasibility and detection rate of T790M mutation in a Latin American population.

Tissue and Plasma-Based Highly Sensitive Blocker Displacement Amplicon Nanopore Sequencing for EGFR Mutations in Lung Cancer.

The epidermal growth factor receptor (EGFR) mutation is a widely prevalent oncogene driver in non-small cell lung cancer (NSCLC) in East Asia. The detection of EGFR mutations is a standard biomarker test performed routinely in patients with NSCLC for the selection of targeted therapy. Here, our objective was to develop a portable new technique for detecting EGFR (19Del, T790M, and L858R) mutations based on Nanopore sequencing. The assay employed a blocker displacement amplification (BDA)-based polymerase chain reaction (PCR) technique combined with Nanopore sequencing to detect EGFR mutations. Mutant and wild-type EGFR clones were generated from DNA from H1650 (19Del heterozygous) and H1975 (T790M and L858R heterozygous) lung cancer cell lines. Then, they were mixed to assess the performance of this technique for detecting low variant allele frequencies (VAFs). Subsequently, formalin-fixed, paraffin-embedded (FFPE) tissue and cell-free DNA (cfDNA) from patients with NSCLC were used for clinical validation. The assay can detect low VAF at 0.5% mutant mixed in wild-type EGFR. Using FFPE DNA, the concordance rates of EGFR 19Del, T790M, and L858R mutations between our method and Cobas real-time PCR were 98.46%, 100%, and 100%, respectively. For cfDNA, the concordance rates of EGFR 19Del, T790M, and L858R mutations between our method and droplet digital PCR were 94.74%, 100%, and 100%, respectively. The BDA amplicon Nanopore sequencing is a highly accurate and sensitive method for the detection of EGFR mutations in clinical specimens.

Inhibiting G6PD by quercetin promotes degradation of EGFR T790M mutation

EGFRT790M mutation causes resistance to the first-generation tyrosine kinase inhibitors (TKIs) in patients with non-small cell lung cancer (NSCLC). However, the therapeutic options for sensitizing first TKIs and delaying the emergence of EGFRT790M mutant are limited. In this study, we show that quercetin directly binds with glucose-6-phosphate dehydrogenase (G6PD) and inhibits its enzymatic activity through competitively abrogating NADP+ binding in the catalytic domain. This inhibition subsequently reduces intracellular NADPH levels, resulting in insufficient substrate for methionine reductase A (MsrA) to reduce M790 oxidization of EGFRT790M and inducing the degradation of EGFRT790M. Quercetin synergistically enhances the therapeutic effect of gefitinib on EGFRT790M-harboring NSCLCs and delays the acquisition of the EGFRT790M mutation. Notably, high levels of G6PD expression are correlated with poor prognosis and the emerging time of EGFRT790M mutation in patients with NSCLC. These findings highlight the potential implication of quercetin in overcoming EGFRT790M-driven TKI resistance by directly targeting G6PD.

P2.09-33 A Phase II Trial of Anlotinib Plus Osimertinib in Advanced NSCLC with EGFR T790M Mutation After Failure of Prior EGFR TKIs

P2.09-33 A Phase II Trial of Anlotinib Plus Osimertinib in Advanced NSCLC with EGFR T790M Mutation After Failure of Prior EGFR TKIs

EP12.01-14 First-line Aumolertinib Treatment in Non-Small Cell Lung Cancer (NSCLC) with Primary EGFR T790M Mutation: A Report of two Cases

EP12.01-14 First-line Aumolertinib Treatment in Non-Small Cell Lung Cancer (NSCLC) with Primary EGFR T790M Mutation: A Report of two Cases

In vivo evaluation of the pharmacokinetic interactions between almonertinib and rivaroxaban, almonertinib and apixaban.

Background: Almonertinib, a third-generation epidermal growth factor receptor tyrosine kinase inhibitor (EGFR-TKI), is commonly used as a first-line treatment for non-small cell lung cancer (NSCLC) patients with EGFR T790M mutations. Rivaroxaban and apixaban are a selective, direct factor Xa inhibitor used to treat venous thromboembolism (VTE), which is a frequent complication of NSCLC. Rivaroxaban and apixaban are substrates of CYP3A4, P-gp and BCRP, whereas almonertinib is an inhibitor of P-gp and BCRP. Rivaroxaban or apixaban are often prescribed together with almonertinib in NSCLC patients, but clear information on pharmacokinetic drug interaction is lacking. Therefore, this study aimed to unravel the extent of interactions between almonertinib-rivaroxaban and almonertinib apixaban in rats, and whether the pharmacokinetic interaction can be mitigated by rivaroxaban and apixaban dose adjustment. Methods: Rats were divided into ten groups (n = 6) that received rivaroxaban (2mg/kg) (group 1), apixaban (0.5mg/kg) (group 2), almonertinib (15mg/kg) (group 3, group 4), almonertinib with rivaroxaban (2mg/kg) (group 5), almonertinib with rivaroxaban (1mg/kg) (group 6), almonertinib with apixaban (0.5mg/kg) (group 7), almonertinib with apixaban (0.25mg/kg) (group 8), rivaroxaban (2mg/kg) with almonertinib (group 9), apixaban (0.5mg/kg) with almonertinib (group 10). The concentrations of drugs were determined by an ultra-performance liquid chromatography tandem mass spectrometry (UPLC-MS/MS). The levels of messenger RNA were determined using quantitative real-time polymerase chain reaction (qRT-PCR). Results and Discussion: The results indicate that almonertinib increased the Cmax and AUC0-t of 2mg/kg rivaroxaban by 3.30 and 3.60-fold, 1mg/kg rivaroxaban by 1.28 and 1.90-fold. Almonertinib increased the Cmax and AUC0-t of 0.5mg/kg apixaban by 2.69 and 2.87-fold, 0.25mg/kg apixaban by 2.19 and 2.06-fold. In addition, rivaroxaban also increased systemic exposure to almonertinib. The results of qRT-PCR showed that almonertinib reduced the expression of Cyp3a1 in liver and intestine, and Abcb1a, Abcg2 in intestine and kidney. The pharmacokinetic results suggest that it is important to take special care of the interactions of these drugs in clinical applications.

Design and synthesis of 4th generation EGFR inhibitors against human triple (Del19/T790M/C797S) mutation

Epidermal growth factor receptor (EGFR)-targeted therapy is used to treat EGFR mutation-induced non-small cell lung cancer (NSCLC). However, its efficacy does not last beyond a certain period due to the development of primary and secondary resistance. First and second-generation inhibitors (e.g., gefitinib, erlotinib, and afatinib) induce EGFR T790M mutations, while third-generation inhibitors (e.g., osimertinib) induce C797S as a major target resistance mutation. Therefore, the C797S mutation is being actively researched. In this study, we investigated the structure-activity relationship of several synthesized compounds as fourth-generation inhibitors against the C797S mutation. We identified a compound 13k that displayed nanomolar potency and high selectivity. Moreover, we used a triple mutant xenograft mouse model to evaluate the in vivo efficacy of 13k in inhibiting EGFR C797S, which demonstrated exceptional profiles and satisfactory EGFR C797S inhibition efficacy. Based on its excellent in vitro and in vivo profiles, compound 13k can be considered a promising candidate for treating EGFR C797S mutations.

Befotertinib: First Approval.

Befotertinib (Surmana®) is an orally administered, highly selective, third-generation epidermal growth factor receptor (EGFR) tyrosine kinase inhibitor (TKI) being developed by Betta Pharmaceuticals and InventisBio for the treatment of non-small cell lung cancer (NSCLC). In May 2023, befotertinib was approved in China for the second-line treatment of patients with locally advanced or metastatic NSCLC who have received EGFR TKI therapy and have disease progression with positive EGFR T790M mutation. Befotertinib is under regulatory review for the first-line treatment of NSCLC in China. Clinical studies assessing befotertinib as an adjuvant therapy after surgery for early EGFR-mutant NSCLC (phaseIII) and in combination with icotinib for advanced or metastatic EGFR-mutant NSCLC (phaseII) are currently underway in China. This article summarizes the milestones in the development of befotertinib leading to this first approval for the second-line treatment of EGFR T790M-mutated locally advanced or metastatic NSCLC.

In silico screening combined with bioactivity evaluation to identify AMI-1 as a novel anticancer compound by targeting AXL

Recently, some studies have proven that AXL plays a crucial role in the drug resistance of tumors. At present, no AXL inhibitors on the market and it is essential to discover novel compounds targeting AXL to overcome resistance. In this work, based on the anchor structure, 21,313 compounds were obtained by substructure search from more than 400,000 compounds. Then, the Qvina and Ledock were selected for virtual screening to obtain 17 compounds. Next, four compounds (ARRY614, AMI-1, NG25, and Butein) were selected for bioactivity evaluation after hydrogen bond and cluster analysis. Further activity evaluation suggested that the compound AMI-1 is a novel AXL inhibitor with an IC50 value of 1.13 uM. In addition, molecular dynamics simulation demonstrated that compound AMI-1 contained lower binding energy and more key residues than the other three compounds, showing the best inhibitory activity against AXL. Finally, further MM/PBSA prediction showed that AMI-1 is more sensitive to mutant protein 3IKA than wildtype protein 1M17, which means that the AMI-1 may be helpful to overcome the resistance of EGFRT790M mutations. In conclusion, this work successfully discovered a novel compound with moderate inhibitory activity against AXL by a drug discovery workflow, which also could be applied to discover active compounds for other targets quickly. Communicated by Ramaswamy H. Sarma

Real-world clinical evidence of lazertinib use in acquired EGFR T790M mutated non-small cell lung cancer.

Lazertinib is a third generation epidermal growth factor receptor (EGFR) tyrosine kinase inhibitor (TKI) designed to overcome EGFR T790M mutation. Currently, lazertinib is approved for usage in the acquired EGFR T790M mutation population based on promising clinical and safety profiles. In this study, we evaluated the clinical outcomes of lazertinib in acquired EGFR T790M mutated non-small cell lung cancer (NSCLC) patients in a real-world clinical setting. Clinical outcomes of 103 patients treated with lazertinib, from July 2021 to August 2022, for NSCLC with acquired EGFR T790M mutation were retrospectively analyzed. EGFR T790M mutation was confirmed using either a cell-free EGFR test (48.5%) or a tissue-based test (51.5%). The median follow-up duration was 11.4 months [95% confidence interval (CI): 10.4-13.1], and 58.3% of patients remained on treatment at the time point of data analysis. The objective response rate was 72.8%. The median progression-free survival (PFS) was not reached, and the PFS rates at 6 and 12 months were 81.7% and 65.1%, respectively. The median PFS in a subgroup treated with lazertinib based on T790M-positive tissue was significantly longer than that in a subgroup treated based on T790M-positive plasma (not reached vs. 14.5 months) (hazard ratio, 0.43; 95% CI: 0.21-0.87). Related to adverse events, there was no treatment-related mortality. However, the lazertinib dose was adjusted in 39 patients (37.9%), including 10 patients (9.7%) with permanent discontinuation. Peripheral sensory-motor related adverse events were observed in 65 patients (63.1%) (paresthesia: n=58; muscle cramping: n=24), leading to dose reduction and permanent discontinuation in 17 (16.5%) and 5 (4.9%) patients, respectively. There was no difference in PFS between the groups with and without dose-adjustment (P=0.40). Our result demonstrates the real-world clinical efficacy of lazertinib in acquired EGFR T790M mutation. Although dose reduction due to adverse events was not uncommon, it did not impair clinical efficacy of lazertinib.

Real-World Evidence of EGFR Targeted Therapy in NSCLC– A Brief Report of Decade Long Single Center Experience

The significance of EGFR targeted therapy in the lung adenocarcinoma is paramount. Several controlled clinical trials have reported considerable survival of EGFR mutation positive patients on receiving the EGFR tyrosine kinase inhibitor (TKI). However, the real-world evidence of benefits of EGFR TKI would be further useful to understand how the designated therapeutic regimen benefits the patients. In this study, we report a decade long real-world evidence of EGFR molecular testing in lung cancer at Tata Memorial Hospital (Mumbai, India). Laboratory and hospital records containing basic demographic details, clinical characteristics, treatment regimen, survival outcome were collected retrospectively. Statistical association and survival analysis were performed using the R programming. The cohort includes 9,053 lung cancer patients tested for EGFR mutations during 2011 to 2019. Baseline T790M and compound mutations were the only mutations observed co-occurring while all other EGFR mutations were mutually exclusive. Furthermore, the baseline T790M were also observed to be associated with TTF1 positivity, smoking and local metastasis. Overall survival of the patients harboring co-occurring compound mutations was significantly lesser than the other EGFR positive patients. Overall, our study suggests that EGFR TKI may provide real-world benefit to the lung cancer patients harboring mutually exclusive EGFR mutations. On the other hand, further systematic study is essential to develop better therapeutic regimen for co-occurring baseline EGFR T790M and other compound mutations.

SDPS-44 RAPID DETECTION OF MUTATIONS IN CSF-CFTNA WITH THE GENEXUS INTEGRATED SEQUENCER

Abstract Brain metastases commonly arise in patients with lung and breast carcinomas and pose distinctive clinical challenges. Genomic alterations are fundamental for diagnosis and therapy selection in cancer patients. However, the turn-around-time (TAT) of standard next generation sequencing (NGS) assays is a limiting factor in the timely delivery of genomic information for clinical decision making. The GenexusTM Sequencer automates the NGS workflow delivering results in less than 24hrs. The Oncomine Precision Assay (OPA) evaluates somatic mutations, copy number variations and fusions in hot-spot regions of 50 cancer-related genes. In this study, we evaluated genomic alterations in 46 cerebrospinal fluid (CSF) samples from 33 patients with metastatic lung cancer (mLC) (N=32) and metastatic breast cancer (mBC) (N=14) to the brain. Cell-free total nucleic acids, (cfTNA) were extracted using QIAamp Circulating Nucleic Acid kit with cfDNA concentrations ranging from 0.1-11.2(ng/ul) and 0.5-6.6 (ng/ul) for mLC and mBC samples, respectively. Median base coverage was 37,913X and 33,576.5X for mLC and mBC samples, respectively, with cfDNA input ranging from 2-20ng. Mutations were detected in 15/32 (46.8%) mLC and 8/14 (57.1%) mBC CSF samples. Among the samples with no mutations detected, 18/23 (78.2%) had suboptimal DNA input (<20ng). The EGFR exon 19 deletion was detected in 4 samples from one patient, with increasing mutant allele fraction in CSF over time, highlighting the potential of CSF-cfTNA analysis for monitoring patients. Moreover, the EGFR T790M mutation was detected in a patient with prior EGFR inhibitor treatment. In addition, ESR1 D538G and ESR1::CCDC170 alterations, associated with endocrine therapy resistance, were detected in 2 mBC patients. The average TAT from cfTNA-to-results was ~16hrs. In summary, our results indicate that CSF-cfTNA analysis with the OPA in the Genexus instrument can provide clinically relevant information in patients with brain metastases with a short TAT.

EGFR-T790M Mutation–Derived Interactome Rerouted EGFR Translocation Contributing to Gefitinib Resistance in Non-Small Cell Lung Cancer

Secondary mutation, T790M, conferring tyrosine kinase inhibitors (TKIs) resistance beyond oncogenic epidermal growth factor receptor (EGFR) mutations presents a challenging unmet need. Although TKI-resistant mechanisms are intensively investigated, the underlying responses of cancer cells adapting drug perturbation are largely unknown. To illuminate the molecular basis linking acquired mutation to TKI resistance, affinity purification coupled mass spectrometry was adopted to dissect EGFR interactome in TKI-sensitive and TKI-resistant non-small cell lung cancer cells. The analysis revealed TKI-resistant EGFR-mutant interactome allocated in diverse subcellular distribution and enriched in endocytic trafficking, in which gefitinib intervention activated autophagy-mediated EGFR degradation and thus autophagy inhibition elevated gefitinib susceptibility. Alternatively, gefitinib prompted TKI-sensitive EGFR translocating toward cell periphery through Rab7 ubiquitination which may favor efficacy to TKIs suppression. This study revealed that T790M mutation rewired EGFR interactome that guided EGFR to autophagy-mediated degradation to escape treatment, suggesting that combination therapy with TKI and autophagy inhibitor may overcome acquired resistance in non-small cell lung cancer.

Epidermal Growth Factor Receptor T790M Mutation Testing in Non-Small Cell Lung Cancer: An International Collaborative Study to Assess Molecular EGFR T790M Testing in Liquid Biopsy.

The detection of the EGFR T790M (T790M) mutation in non-small cell lung cancer (NSCLC) patients who progressed under treatment with first- or second-generation EGFR-tyrosine kinase inhibitors (TKIs) is important to offer a subsequent therapy with a third-generation EGFR-TKI. Liquid biopsy is a powerful tool to determine the T790M mutation status. Several liquid biopsy platforms with varying degrees of accuracy are available to test for T790M mutations, and sensitivities may differ among these methods. As no standard exists for the testing of T790M mutation in liquid biopsy, we performed a collaborative study to describe and compare the sensitivity of different in-house liquid biopsy platforms for the detection of the T790M mutation, EGFR exon 19 deletion (del19) and EGFR L858R mutation (L858R) across multiple participating laboratories in seven Central and Eastern European countries. Of the 25 invited laboratories across Central and Eastern Europe, 21 centers participated and received 10 plasma samples spiked with cell-line DNA containing the T790M, del19, or L858R mutation in different concentrations. In-house PCR-based and NGS-based methods were used accordingly, and results were reported as in routine clinical practice. Two laboratories, which used the AmoyDx® EGFR 29 Mutations Detection Kit (AmoyDx) with Cobas® cfDNA Sample Preparation Kit and QX200 Droplet Digital PCR (ddPCR) with the QIAamp Circulating Nucleic Acid Kit identified all ten samples correctly. Cobas® EGFR Mutation Test v2 (Cobas), the NGS methods, and the IdyllaTM detection method used in this study performed within the known sensitivity range of each detection method. If a negative result was obtained from methods with lower sensitivity (e.g., Cobas), repeated liquid biopsy testing and/or tissue biopsy analysis should be performed whenever possible, to identify T790M-positive patients to allow them to receive the optimal second-line treatment with a third-generation EGFR TKI.

Clinical Utility of Mobocertinib in the Treatment of NSCLC - Patient Selection and Reported Outcomes.

Mobocertinib is an oral tyrosine kinase inhibitor (TKI) that selectively targets epidermal growth factor receptor exon 20 insertion (EGFRex20ins) mutations. It is a structural analog of the third-generation TKI osimertinib, which targets EGFR T790M mutant non-small cell lung cancer (NSCLC); however, mobocertinib gains selectivity for EGFRex20ins mutants over wild type (WT) by interacting with the C790 gatekeeper residue of EGFR. This is accomplished via a carboxylated isopropyl ester moiety at the C5-position of mobocertinib's central pyrimidine core. In Phase 1/2 dose-escalation and dose-expansion studies, mobocertinib was found to have an investigator-confirmed overall response rate (ORR) of 56% (9/16; 95% CI: 30-80%) and 25% (3/12; 95% CI: 5-57%) in patients without and with baseline brain metastasis, respectively. Median investigator-assessed progression-free survival (mPFS) was 10.2 months (95% CI: 5.6 - not reached) and 3.7 months (95% CI: 1.8-15.9) in patients without and with baseline brain metastasis, respectively. A third phase evaluated patients who had received pre-treatment with platinum-based chemotherapy (PPP) and included an extension cohort (EXCLAIM cohort) which evaluated patients treated previously with 1 or 2 lines of therapy. An Independent Review Committee (IRC) found both cohorts to have similar outcomes in terms of ORR, median time to response, mPFS, and disease progression or death. The treatment-emergent adverse events (TEAE) related to mobocertinib are similar to other EGFR inhibitors and are predominately gastrointestinal (eg diarrhea, nausea, vomiting) and cutaneous (eg rash). In September 2021, the FDA granted accelerated approval for mobocertinib in the treatment of patients with locally advanced or metastatic NSCLC with EGFRex20ins mutation whose disease progressed while on platinum-based chemotherapy. The present review describes data that led to the approval of mobocertinib.

Osimertinib Induces the Opposite Effect of Proliferation and Migration in the Drug Resistance of EGFR-T790M Non-small Cell Lung Cancer Cells.

Lung cancer has become one of the leading causes of cancer incidence and mortality worldwide. Non-small cell lung carcinoma (NSCLC) is the most common type among all lung cancer cases. NSCLC patients contained high levels of activating epidermal growth factor receptor (EGFR) mutations, such as exon 19 deletion, L858R and T790M. Osimertinib, a third-generation of EGFR tyrosine kinase inhibitor (EGFR-TKI), has therapeutic efficacy on the EGFR-T790M mutation of NSCLC patients; however, treatment of osimertinib still can induce drug resistance in lung cancer patients. Therefore, investigation of the drug resistance mechanisms of osimertinib will provide novel strategies for lung cancer therapy. The H1975OR osimertinib-resistant cell line was established by prolonged exposure with osimertinib derived from the H1975 cells. The cell proliferation ability was evaluated by the cell viability and cell growth assays. The cell migration ability was determined by the Boyden chamber assays. The differential gene expression profile was analyzed by genome-wide RNA sequencing. The protein expression and location were analyzed by western blot and confocal microscopy. In this study, we established the osimertinib-resistant H1975 (T790M/L858R) cancer cells, named the H1975OR cell line. The cell growth ability was decreased in the H1975OR cells by comparison with the H1975 parental cells. Conversely, the cell migration ability was elevated in the H1975OR cells. We found the differential gene expression profile of cell proliferation and migration pathways between the H1975OR and H1975 parental cells. Interestingly, the protein levels of phospho-EGFR, PD-L1, E-cadherin and β-catenin were decreased, but the survivin and N-cadherin proteins were increased in the H1975OR drug-resistant cells. Osimertinib induces the opposite effect of proliferation and migration in the drug resistance of EGFRT790M lung cancer cells. We suggest that differential gene and protein expressions in the cell proliferation and migration pathways may mediate the drug resistance of osimertinib in lung cancer cells. Understanding the molecular drugresistant mechanisms of proliferation and migration pathways of osimertinib may provide novel targets and strategies for the clinical treatment of EGFR-TKIs in lung cancer patients.

Safety and preliminary efficacy of YK-029A, a novel EGFR TKI, in patients with advanced NSCLC harboring ex20ins, T790M or rare mutations.

9014 Background: This study aimed to evaluate the safety and preliminary efficacy of YK-029A, a novel third-generation epidermal growth factor receptor (EGFR) tyrosine kinase inhibitor, in treated or untreated patients with advanced NSCLC. Methods: This dose-escalation and dose-expansion phase 1 trial recruited previously untreated or treated patients with EGFR ex20ins mutant locally advanced or metastatic NSCLC and previously treated patients with EGFR T790M or rare mutations. In dose-escalation phase, patients with EGFR T790M mutation were enrolled. YK-029A was given at doses of 50, 100, 150, 200 to 250 mg/day (3+3 design). In dose-expansion phase, patients with EGFR T790M, EGFR ex20ins, or rare mutations were enrolled. The primary objective was safety. Dose-limiting toxicity (DLT) and maximum tolerated dose (MTD) were explored. In the treatment-naïve cohort of EGFR ex20ins mutant NSCLC, patients were administered oral YK-029A 200 mg once daily in a 28-day cycle, and efficacy was assessed by the independent review committee. The study was registered (chinadrugtrials.org.cn,CTR20180350). Results: A total of 108 were included in the safety analysis set. DLT did not occur in dose-escalation phase. MTD was not reached. Treatment-emergent adverse events (TEAEs) of any grade and grade≥3 occurred in 106 (98.1%) and 41 (38.0%) patients, respectively. Treatment-related adverse events (TRAEs) of any grade and grade≥3 occurred in 102 (94.4%) and 30 (27.8%) patients, respectively. One patient had liver abscess related to YK-029A and died. Three patients terminated the treatment because of TEAEs. The most common TRAEs were diarrhea (46.3%), anemia (38.0%), and rash (32.4%). For the treatment-naïve EGFR ex20ins mutant cohort, 26 patients were included in the efficacy analysis set. Most patients were adenocarcinoma (96.4%) and at stage IV (85.7%). At the cut-off date on October 30, 2022, 19 patients (73.1%) had partial remission, five patients (19.2%) had stable disease, and two patients (7.7%) developed disease progression. The confirmed objective response rate achieved 73.1% (95% confidence interval [CI], 52.21% to 88.43%). The median progression-free survival was 9.3 months (95% CI, 5.85 to not evaluated). Conclusions: YK-029A was well tolerated and showed preliminary efficacy in treatment-naïve EGFR ex20ins mutant patients with locally advanced or metastatic NSCLC. [Table: see text]

A nation-wide genomic screening project for further development of targeted therapies in treatment-refractory non–small-cell lung cancer (LC-SCRUM-TRY).

9097 Background: Targeted therapies based on oncogenic drivers demonstrate dramatic and durable response in patients with non-small cell lung cancer (NSCLC). However, acquired resistance inevitably develop by diverse genomic resistance mechanisms. Genotype-matched targeted therapies to overcome treatment-resistance have not been established, except osimertinib against EGFR T790M mutation. Methods: We established a nation-wide genomic screening project in treatment-resistant NSCLC (LC-SCRUM-TRY; UMIN000041957) in September 2020 to identify the genetic resistant alterations, and to promote clinical therapeutic development. Enrolled patients have been screened for genetic alterations using a rapid next-generation sequencing (NGS) system, Oncomine Precision Assay (OPA) for tissue samples, and Guardant 360 (G360) or OPA for plasma samples. MET amplification was also evaluated by FISH for NSCLC post EGFR-TKI treatment. Results: As of January 2023, 129 institutions in Japan were participating, and 1252 patients had been enrolled. Sample types were tissue (84%), and plasma (16%), respectively. Turn-around-time (median [interquartile range]) of OPA and G360 was 5 (4-6), and 9 (8-10.5) days, respectively. Of these, a total of 711 (57%) were already identified to have oncogenic driver at enrollment ( EGFR, 556 [43%]; ALK, 70 [6%]; RET, 22 [2%]; ROS1, 21 [2%]; KRAS, 15 [1%]; ERBB2 exon 20 insertion [ex20ins], 8 [0.6%]; MET exon 14 skipping [ex14skip], 8 [0.6%]; BRAF V600E, 7 [0.6%]; NTRK3, 2 [0.2%]; others, 2 [0.2%]). Of 556 EGFR-mutated NSCLC, 537 (97%) were enrolled post EGFR-TKIs. EGFR mutation subtypes were exon 19 deletion (52%), L858R (41%), ex20ins (1%), others (6%), respectively. Of 537 EGFR-TKI resistant tumors, 326 (40%) had at least one genetic alteration related with drug resistance, including EGFR alterations (amplification [13%], C797S [4%], A750P [3%], E709X [2%], L792X [1%], L718Q [1%]), MET amp (16%), and other driver mutation/rearrangement (8%). Through this screening, 37 (7%) of patients resistant to EGFR-TKI were enrolled into clinical trials, with 16/102 (16%) patients with targetable alterations ( MET amp or EGFR C797S). In addition, of 541 NSCLC without oncogenic drivers at enrollment, 116 (21%) were identified to have actionable oncogenic drivers with FDA-approved drug (KRAS G12C, 23 [4%]; ERBB2 ex20ins, 23 [4%]; RET, 13 [2%]; MET ex14skip, 13 [2%]; EGFR except ex20ins, [4%]; EGFR ex20ins, 10[2%]; ALK, 6 [1%]; ROS1, 5 [1%]). Conclusions: LC-SCRUM-TRY contributes to the clinical development of precision medicine to overcome drug resistance, especially for EGFR-mutated NSCLC resistant to EGFR-TKI. This screening platform also help to practice precision medicine for patients initially diagnosed as driver-negative. Clinical trial information: UMIN000041957 .