Patients Harboring EGFR Mutations Research Articles

The impact of postoperative adjuvant therapy on EGFR-mutated stage IA lung adenocarcinoma with micropapillary pathological subtypes

BackgroundMicropapillary (MPP) adenocarcinoma is considered one of the most aggressive pathological types of lung adenocarcinoma (LADC). This retrospective study aimed to evaluate the prognostic significance and benefit of postoperative adjuvant therapy (PAT) in stage IA LADC patients with different proportions of MPP components.Materials and methodsWe retrospectively examined clinical stage IA LADC patients who underwent surgical resection between August 2012 and December 2019. In terms of the proportion of MPP components (TPM), the tumors were reclassified into three categories: MPP patterns absent (TPMN); low proportions of MPP components (TPML); and high proportions of MPP components (TPMH). The dates of recurrence and metastasis were identified based on physical examinations and were confirmed by histopathological examination.ResultsOverall, 505 (TPMN, n = 375; TPML, n = 92; TPMH, n = 38) patients harboring EGFR mutations were enrolled in the study. Male sex (P = 0.044), high pathological stage (P < 0.001), and MPP pathological subtype (P < 0.001) were more frequent in the TPM-positive (TPMP) group than in the TPM-negative (TPMN) group. Five-year disease-free survival (DFS) rates were significantly lower in the TPMP group than in the TPMN group (84.5% vs. 93.4%, P = 0.006). In addition, patients with high proportions (greater than 10%) of MPP components had worse overall survival (OS) (91.0% vs. 98.9%, P = 0.025) than those with low proportions (5%≤ TPM ≤ 10%). However, postoperative EGFR tyrosine kinase inhibitors (TKIs) or adjuvant chemotherapy (ACT) cannot improve DFS and OS between EGFR-mutated patients with different proportions of MPP components.ConclusionMPP was related to earlier recurrence and shortened survival time, even in stage IA. Further research needs a larger sample size to clarify that EGFR-mutated stage IA patients with MPP components obtain survival benefits from adjuvant therapy.

EGFR Mutation and TKI Treatment Promote Secretion of Small Extracellular Vesicle PD-L1 and Contribute to Immunosuppression in NSCLC.

In Asian populations with non-small-cell lung cancer (NSCLC), EGFR mutations are highly prevalent, occurring in roughly half of these patients. Studies have revealed that individuals with EGFR mutation typically fare worse with immunotherapy. In patients who received EGFR tyrosine kinase inhibitor (TKI) treatment followed by anti-PD-1 therapy, poor results were observed. The underlying mechanism remains unclear. We used high-resolution flow cytometry and ELISA to detect the circulating level of small extracellular vesicle (sEV) PD-L1 in NSCLC individuals with EGFR mutations before and after receiving TKIs. The secretion amount of sEV PD-L1 of lung cancer cell lines with EGFR mutations under TKI treatment or not were detected using high-resolution flow cytometry and Western blotting. The results revealed that patients harboring EGFR mutations exhibit increased levels of sEV PD-L1 in circulation, which inversely correlated with the presence of CD8+ T cells in tumor tissues. Furthermore, tumor cells carrying EGFR mutations secrete a higher quantity of PD-L1-positive sEVs. TKI treatment appeared to amplify the levels of PD-L1-positive sEVs in the bloodstream. Mutation-induced and TKI-induced sEVs substantially impaired the functionality of CD8+ T cells. Importantly, our findings indicated that EGFR mutations and TKI therapies promote secretion of PD-L1-positive sEVs via distinct molecular mechanisms, namely the HRS and ALIX pathways, respectively. In conclusion, the increased secretion of PD-L1-positive sEVs, prompted by genetic alterations and TKI administration, may contribute to the limited efficacy of immunotherapy observed in EGFR-mutant patients and patients who have received TKI treatment.

Bioinformatics-driven discovery of novel EGFR kinase inhibitors as anti-cancer therapeutics: In silico screening and in vitro evaluation.

Epidermal growth factor receptor EGFR inhibitors are widely used as first line therapy for the treatment of non-small-cell lung cancer (NSCLC) in patients harboring EGFR mutation. However, the acquisition of a second-site mutation (T790 M) limited the efficacy and developed resistance. Therefore, discovery and development of specific drug target for this mutation is of urgent needs. In our study we used the ChemDiv diversity database for receptor-based virtual screening to secure EGFR-TK inhibitors chemotherapeutics. We identified four compounds that bind to the ATP-binding region of the EGFR-TK using AutoDock 4.0 and AutoDock Vina1.1.2 and post-docking investigations. The ligand showed hydrophobic interactions to the hydrophobic region of the binding site and engaged in hydrogen bonding with Met793. The ligands also explored π-cation interactions between the π-system of the ligand-phenyl ring and the positive amino group of Lys745. Molecular mechanics Poisson-Boltzmann surface area MM/PBSA per-residue energy decomposition analyses revealed that Val726, Leu792, Met793, Gly796, Cys797, Leu798, and Thr844 contributed the most to the binding energy. Biological evaluation of the retrieved hit compounds showed suppressing activity against EGFR auto phosphorylation and selective apoptosis-induced effects toward lung cancer cells harboring the EGFR L858R/T790M double mutation. Our work anticipated into novel and specific EGFR-TKIs and identified new compounds with therapeutic potential against lung cancer.

Survival benefit in EGFR-wild and ALK negative NSCLC patients who participate in clinical trials compared to standard-of-care: Propensity-matched analysis

ObjectivesAdvanced non-small cell lung cancer patients harboring EGFR mutation or ALK fusion have achieved significant survival benefit with targeted agents. In contrast, EGFR-wild type and ALK negative lung adenocarcinoma still have poor survival outcome. This study assessed the impact of participating in clinical trials on clinical outcomes in patients with EGFR-wild-type and ALK-negative lung adenocarcinoma. Materials and methodsThis study included patients with advanced EGFR-wild-type and ALK-negative lung adenocarcinoma who received systemic treatment between March 2017 and June 2022. We compared clinical outcomes between patients who participated in clinical trials and those treated with standard-of-care (SOC) using propensity score matching (PSM). ResultsOverall, 1,686 patients with EGFR-wild-type and ALK-negative advanced lung adenocarcinoma were included in the final analysis. Of these, 1,380 (81.9 %) received SOC only and 306 (18.1 %) patients were enrolled in at least one clinical trial during their cancer journey. After PSM (1:1), 612 patients were matched to the SOC (n = 306) and clinical trial (n = 306) groups. Among those who participated in clinical trials, 27.8 % and 72.2 % were included in clinical trials involving targeted therapy and immunotherapy respectively. In the clinical trial group, more patients received targeted therapy (31.7 % vs. 5.5 %, p < 0.001) and immunotherapy (88.6 % vs. 62.8 %, p < 0.001) compared to the SOC group. The median overall survival was 17.1 months (95 % confidence interval [CI], 13.2–21.4) in the SOC group and 27.3 months (95 % CI, 22.1–32.4) in the clinical trial group (hazard ratio = 0.71, [95 % CI, 0.58–0.88, P = 0.002]). ConclusionsThis study demonstrated that participating in clinical trials resulted in a survival benefit that reduced the risk of death by 29.6% compared to receiving SOC in EGFR-wild-type and ALK-negative lung adenocarcinoma.

NEAT1_1 confers gefitinib resistance in lung adenocarcinoma through promoting AKR1C1-mediated ferroptosis defence

Gefitinib is one of the most extensively utilized epidermal growth factor receptor-tyrosine kinase inhibitors (EGFR-TKIs) for treating advanced lung adenocarcinoma (LUAD) patients harboring EGFR mutation. However, the emergence of drug resistance significantly compromised the clinical efficacy of EGFR-TKIs. Gaining further insights into the molecular mechanisms underlying gefitinib resistance holds promise for developing novel strategies to overcome the resistance and improve the prognosis in LUAD patients. Here, we identified that the inhibitory efficacy of gefitinib on EGFR-mutated LUAD cells was partially dependent on the induction of ferroptosis, and ferroptosis protection resulted in gefitinib resistance. Among the ferroptosis suppressors, aldo-keto reductase family 1 member C1 (AKR1C1) exhibited significant upregulation in gefitinib-resistant strains of LUAD cells and predicted poor progression-free survival (PFS) and overall survival (OS) of LUAD patients who received first-generation EGFR-TKI treatment. Knockdown of AKR1C1 partially reversed drug resistance by re-sensitizing the LUAD cells to gefitinib-mediated ferroptosis. The decreased expression of miR-338-3p contributed to the aberrant upregulation of AKR1C1 in gefitinib-resistant LUAD cells. Furthermore, upregulated long non-coding RNA (lncRNA) nuclear paraspeckle assembly transcript 1_1 (NEAT1_1) sponged miR-338-3p to neutralize its suppression on AKR1C1. Dual-luciferase reporter assay and miRNA rescue experiment confirmed the NEAT1_1/miR-338-3p/AKR1C1 axis in EGFR-mutated LUAD cells. Gain- and loss-of-function assays demonstrated that the NEAT1_1/miR-338-3p/AKR1C1 axis promoted gefitinib resistance, proliferation, migration, and invasion in LUAD cells. This study reveals the effects of NEAT1_1/miR-338-3p/AKR1C1 axis-mediated ferroptosis defence in gefitinib resistance in LUAD. Thus, targeting NEAT1_1/miR-338-3p/AKR1C1 axis might be a novel strategy for overcoming gefitinib resistance in LUAD harboring EGFR mutation.

High-efficiency EGFR genotyping using cell-free DNA in bronchial washing fluid.

EGFR mutation testing is required for treatment of lung adenocarcinoma using epidermal growth factor receptor-tyrosine kinase inhibitor. However, the amounts of tumor tissue or tumor cells obtained by bronchoscopy are often insufficient. Bronchial washing fluid, obtained by lavage with saline after tumor biopsy or brushing, and the supernatant of bronchial washing fluid are thought to contain cell-free DNA that would be potentially applicable for EGFR testing. From among patients with suspected adenocarcinoma or non-small cell lung carcinoma diagnosed from biopsy or surgical specimens at the University of Tsukuba Hospital between 2015 and 2019, cell-free DNAs from 80 specimens of supernatant of bronchial washing fluid (50 with EGFR mutation and 30 with wild type EGFR) and 8 blood serum samples were examined for EGFR mutation using droplet digital PCR. Among the 50 patients harboring EGFR mutation, the rate of positivity for cell-free DNA extracted from supernatant of bronchial washing fluid was 80% (40/50). In nine of the EGFR mutation-positive cases, tumor cells were not detected by either biopsy or cytology, but the mutation was detected in four cases (4/9, 44%). Comparison of the cell-free DNA mutation detection rate between supernatant of bronchial washing fluid and blood serum in six cases showed that mutations were detected from the former in all cases (6/6, 100%), but from the latter in only one case (1/6, 17%). Using supernatant of bronchial washing fluid samples, the detection rate of EGFR mutation was high, and EGFR mutations were detectable even when no tumor cells had been detectable by biopsy or cytology. Supernatant of bronchial washing fluid might be an effective sample source for EGFR mutation testing.

Revealing distinct immune landscape in EGFR mutant and EGFR wild type lung adenocarcinoma by using single-cell RNA sequencing.

e21008 Background: Non-small cell lung cancer (NSCLC) with EGFR mutations displays heterogeneity in the extent of intratumoral immunocytes infiltration compared to those with EGFR wild types, which may explain their variable responsiveness to PD-1 blockade. Here, we performed single-cell RNA sequencing (scRNA-seq) to unveil the immunescape and heterogeneity of lung adenocarcinoma (LUAD) between EGFR mutant (EGFR-mut) patients and wild type (EGFR-wt) patients. Methods: Eleven EGFR-mut and 7 EGFR-wt NSCLC tumor samples were analyzed. Immune cells (CD45+) were enriched through fluorescence-activated cell sorting (FACS) and subjected to single-cell RNA sequencing (scRNA-seq) using the 10X Genomics platform. Sequencing reads were normalized and analyzed using the R/Seurat package. Cellular components of each sample were determined based on known marker genes. Wilcox test was used to compare promotion by subtype composition and immune cell infiltrates. Results: Different immune cell compositions were observed between EGFR-mut and EGFR-wt LUAD tumor samples. We found EGFR-wt tumors are marked by an enrichment of CCL15+ tumor-associated macrophages(TAMs), which display pro-inflammatory properties and high expressions of TNF-a-signaling genes. In contrast, EGFR-mut tumors exhibit enrichment of SPARCL1+TAMs, which are involved in epithelial-mesenchymal transition (EMT) and angiogenesis. EGFR-wt tumors exhibited enrichment of CD8-Teff-MX1 and Gamma delta T cells, both of which displayed higher cytotoxic and naive features. Moreover, the high expression of Gamma delta T corresponds with a better clinical prognosis. In contrast, CD8-Teff-XCL1 and NKT-FGFBP2 were found enriched in EGFR-mut tumors, both of which contributed to higher exhaustion and decreased cytotoxic function. Additionally, NK-IL32 was found enriched in EGFR-mut tumors, showing a downregulated T cell receptor signaling and stronger exhausted features. The high expression of this subcluster correlated with poor outcomes in LUAD patients harboring EGFR mutation. Conclusions: Our study provided a deeper understanding of the immune landscape of EGFR-mut and EGFR-wt LUAD and gained better insights into the immunological mechanisms involved in the response to ICIs. The results of our study could be instructive for the development of future immunotherapy strategies for NSCLC patients harboring EGFR mutations.

The Additional Exclusions of ROS1 Fusions (In Addition to EGFR Mutation and ALK Fusions) in the Cemiplimab NSCLC FDA Indication (EMPOWER-Lung 1 and -Lung 3). Catching Up with Current Scientific View of Immunotherapy in Never-Smoker Predominant Actionable Driver Mutation Positive NSCLC?

Cemiplimab is one of seven immune checkpoint inhibitors (ICIs) approved for the first-line (1L) treatment of advanced NSCLC in the US based on EMPOWER-Lung 1 and -Lung 3 trials. In addition to exclusion of NSCLC patients harboring EGFR mutations and ALK fusion from 1L treatment with ICIs, exclusion of ROS1 fusion is an additional unique exclusion the use of criterion for cemiplimab in the US FDA indication based on the design of the EMPOWER lung trials. We review the effectiveness of ICIs in never-smoker predominant NSCLC with driver mutations (EGFR, ALK, ROS1, RET, HER2) and question whether exclusion of ROS1 fusion would put cemiplimab at a competitive disadvantage given the requirement for insurance to prove ROS1 fusion negativity. We further discuss whether the US FDA as a regulatory authority has the right and responsibility to harmonize the use of ICIs in these actionable driver mutations to standardize community practice for the benefit of patients and to advance the development of next-generation treatment for these driver mutations.

Epidermal Growth Factor Receptor Mutation Status and the Impact on Clinical Outcomes in Patients with Non-Small Cell Lung Cancer.

Epidermal growth factor receptor (EGFR) mutation status differs according to ethnicity, gender, smoking history, and histology types. The present study aimed to evaluate EGFR mutation status in patients with non-small cell lung cancer (NSCLC) and further explore its association with clinical characteristics and prognosis in advanced NSCLC patients (Stage IIIB-IV). 238 NSCLC patients were enrolled in this study from October 2016 through December 2019. Patient characteristics and clinical data including age, gender, smoking history, histology types, tumor stage, survival status, and time were collected via electronic medical record system or telephone. 21 somatic mutations which spanned exons 18-21 of EGFR were detected using the amplification refractory mutation system-polymerase chain reaction (ARMS-PCR) method, followed by analysis of links to clinical characteristics, progression-free survival (PFS) and overall survival (OS). 103 patients were detected harboring EGFR mutations among the 238 cases tested (43.3%), and exons 19 and 21 were the highest mutation frequencies, with 20.6% and 19.3% respectively. The EGFR mutation rate was much higher in female versus male (57.4% vs 31.5%, p <0.001), in non-smokers compared to smokers (56.8% vs 25.9%, p <0.001), and in those with adenocarcinoma than other histology types (48.3% vs 3.7%, p <0.001). For patients in advanced stage, median PFS was 11 months in patients harboring EGFR mutations, versus 4 months in patients with wild type EGFR (p <0.001); median OS was 24 versus 12 months (p <0.001). Never smoking (p = 0.042) and adenocarcinoma (p = 0.007) were independent favorable factors for EGFR mutations. Our data strengthen the findings of high prevalence of EGFR mutations in Asian patients with NSCLC. Mutations are prevalent in those patients who are female, adenocarcinoma, and have never smoked. Moreover, advanced EGFR mutation-positive patients have better PFS and OS than those with wild type EGFR.

Novel CDK12/13 Inhibitors AU-15506 and AU-16770 Are Potent Anti-Cancer Agents in EGFR Mutant Lung Adenocarcinoma with and without Osimertinib Resistance.

Osimertinib is a third-generation epidermal growth factor receptor and tyrosine kinase inhibitor (EGFR-TKI) approved for the treatment of lung adenocarcinoma patients harboring EGFR mutations. However, acquired resistance to this targeted therapy is inevitable, leading to disease relapse within a few years. Therefore, understanding the molecular mechanisms of osimertinib resistance and identifying novel targets to overcome such resistance are unmet needs of cancer patients. Here, we investigated the efficacy of two novel CDK12/13 inhibitors, AU-15506 and AU-16770, in osimertinib-resistant EGFR mutant lung adenocarcinoma cells in culture and xenograft models in vivo. We demonstrate that these drugs, either alone or in combination with osimertinib, are potent inhibitors of osimertinib-resistant as well as -sensitive lung adenocarcinoma cells in culture. Interestingly, only the CDK12/13 inhibitor in combination with osimertinib, although not as monotherapy, suppresses the growth of resistant tumors in xenograft models in vivo. Taken together, the results of this study suggest that inhibition of CDK12/13 in combination with osimertinib has the potential to overcome osimertinib resistance in EGFR mutant lung adenocarcinoma patients.

Abstract 3886: Analysis of concomitant genetic alterations in advanced EGFR-mutated lung adenocarcinoma by targeted NGS: A multicenter prospective and real world study

Abstract Background:The response of 1st-line EGFR-TKI treatment in advanced EGFR-mutated lung adenocarcinoma patients are highly effective, but its sustainability and clinical course are quite variable from patient to patient. In this study, we investigated the clinical impact of concomitant genetic mutations analyzed by targeted NGS on PFS and acquired resistance in advanced EGFR-mutated lung adenocarcinoma patients. Methods: Eighty-five advanced NSCLC patients harboring EGFR mutations were enrolled prospectively in multi-centers from 2019 to 2022 (NCT04122833). We performed the targeted next generation sequencing on 324 cancer-related genes by Foundation One CDx with pre-treated tumor samples. First- or second-generation EGFR-TKIs(gefitinib, afatinib, or erlotinib) were administered in 1st-line setting. After the progression, tissue re-biopsy or plasma liquid biopsy (FoundationOne Liquid CDx) for NGS if tissue biopsy is difficult or risk was performed. Results: Of the 85 patients (70.6% of female, 65.8% of nonsmoker, 56.4% of E19del and 38.8% of E21 L858R mutation), 50 patients experienced a disease progression in November, 2022. The median PFS was 20 months (95 %CI: 15.2-24.8). The most frequent co-mutations were TP53 (47.1%), CDKN2A/B loss (34.1%), MTAP loss (20%), NKX2-1amp(15.3%), MDM2amp (14.1%), RMB10, CCNE/CCND1 amp, NFKB1 amp (11.8%) and CDK4/6 amp (10.6%). Patients with TP53, CDK4/6 amp and MYC amp were independently associated with shorter PFS. In a multivariate analysis, tumors with copy number alterations such as CDK4/6 amp or Myc amp were also independently associated with shorter PFS. However, the CDKN2A/2B loss, MTAP loss, and MDM amp were not related with the PFS. In the number of co-mutations, patients harboring ≥5 co-mutations identified by NGS had shorter median PFS than patients with 0-1 or 2-4 co-mutations. (mPFS 0-1: 2-4: ≥5 co-mutations=35: 18: 9.3 months, p&amp;lt;0.001). At progression, 22 patients harbored an acquired T790M mutation (25.8%). Before TKI treatment, patients with CDKN2A/B loss, MTP loss or CCND/CCNE1 amp in pretreatment tumor have more acquired T790M mutation after progression significantly (p&amp;lt;0.05) Conclusion: We have demonstrated that concomitant mutations detected by targeted NGS analysis provide significant impact on the drug response and clinical course of advanced EGFR-mutated adenocarcinoma patients treated by 1st-line EGFR-TKIs. It is suggested that targeted NGS along with PCR-based detection will be necessary for precision medicine-based individualized practice of 1st-line EGFR-TKI-based combination treatment. Citation Format: In Ae Kim, Seung Joon Kim, Sung Yong Lee, Chang Min Choi, Jae Cheol Lee, Tae Won Jang, Seung Hun Jang, Chan Kwon Park, Wan Seop Kim, Jae Young Hur, Hee Joung Kim, Young Whan Kim, Key Young Lee. Analysis of concomitant genetic alterations in advanced EGFR-mutated lung adenocarcinoma by targeted NGS: A multicenter prospective and real world study. [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 3886.

Abstract 2232: The identification of novel autophagy flux-related molecules closely linked to the acquired resistance to EGFR TKIs in NSCLC patients harboring EGFR mutations

Abstract Introduction: Non-small cell lung cancer (NSCLC) patients with activating EGFR mutations (mEGFR) well respond to EGFR TKIs, but the majority of patients eventually acquire drug resistance, leading to treatment failure. Recently, intracellular potential autophagy in addition to primary genetic alterations implicates the acquired drug resistance to targeted drugs in various carcinomas such as melanoma, pancreas, and breast cancer. We aimed to identify autophagy flux-related signal molecules which may be closely linked to acquired resistance in mEGFR NSCLC. Methods: We constructed the TMA composed of 579 surgically resected tumor tissues from lung adenocarcinoma patients and evaluated protein expression of autophagy flux-related signal molecules including CAGE, p-Beclin1, LC3B, p-AMPK, ULK1, p62, and ATG5 using immunohistochemistry (IHC). We established H1975OSI (166-folds) and PC9ERL (3,650-folds) resistant sub cell lines through the prolonged exposure of Osimertinib and Erlotinib to H1975 (L858R/T790M) and PC9 (Del19) cells, respectively. We also explored genes that induce autophagy flux activity using mRNA seq and qRT-PCR. Results: H-score of CAGE ( 95.6±7.9, 70±5.5), p-AMPK (73.4±7.8, 32±5.6) and p-Beclin1 (44.4±16.1, 19.7±5.5), ULK1( 57.4±4.9, 41.9±4.9) were significantly higher in mEGFR, compared to those of wild type EGFR NSCLC (P &amp;lt;0.001). According to EGFR mutation subtype, the expressions of CAGE (98±11.2, 70±5.5) and ULK1(60.7±5.0, 41.9±4.9) were significantly higher in Del19 (P&amp;lt;0.001), while the expressions of CAGE(93.2±5.6, 70±5.5,), p-AMPK(82.9±5.7, 32±5.6), and p-Beclin1(45.6±16.7, 19.7±5.5) were significantly higher in L858R (P&amp;lt;0.001). In advanced/metastatic mEGFR NSCLC patients treated with EGFR TKIs, p-Beclin1(13.0±10.9, 59±7.2) expression was significantly increased, when comparing before treatment and at treatment failure (P&amp;lt;0.018). As results of mRNA seq and qRT-PCR in H1975 parental cells and H1975OSI cells, we identified autophagy flux-related signal molecules including BECLIN1, GABAR1, NBR1, PINK1, ULK1 which were significantly increased more than 10 times. Conclusion: Taken together, our results strongly support the evidence that autophagy flux-related signal molecules as well as known genetic alterations are closely connected to the acquired resistance during period of EGFR TKI treatment in mEGFR NSCLC patients. Now, we are undergoing additional RNA profiling and function study of identified novel autophagy-related genes to examine a possibility as potential target to overcome EGFR TKI resistance. Citation Format: Jeong-Oh Kim, Jung-Young Shin, Min-Young Kim, Mi-Ran Lee, Seoree Kim, Hankyu Lee, Doyong Jeon, Seung Ryel Baek, Kim Joo Il, Kyoungjune Lee, Youn Soo Lee, Jin-Hyoung Kang. The identification of novel autophagy flux-related molecules closely linked to the acquired resistance to EGFR TKIs in NSCLC patients harboring EGFR mutations [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 2232.

Therapeutic strategies for EGFR-mutated non-small cell lung cancer patients with osimertinib resistance

Epidermal growth factor receptor tyrosine kinase inhibitors (EGFR-TKIs) are the preferential options for advanced non-small cell lung cancer (NSCLC) patients harboring EGFR mutations. Osimertinib is a potent irreversible third-generation EGFR-TKI targeting EGFR mutations but has little effect on wild-type EGFR. In view of its remarkable efficacy and manageable safety, osimertinib was recommended as the standard first-line treatment for advanced or metastatic NSCLC patients with EGFR mutations. However, as the other EGFR-TKIs, osimertinib will inevitably develop acquired resistance, which limits its efficacy on the treatment of EGFR-mutated NSCLC patients. The etiology of triggering osimertinib resistance is complex including EGFR-dependent and EGFR-independent pathways, and different therapeutic strategies for the NSCLC patients with osimertinib resistance have been developed. Herein, we comprehensively summarized the resistance mechanisms of osimertinib and discuss in detail the potential therapeutic strategies for EGFR-mutated NSCLC patients suffering osimertinib resistance for the sake of the improvement of survival and further achievement of precise medicine.

A potential treatment option for transformed small-cell lung cancer on PD-L1 inhibitor-based combination therapy improved survival

ObjectivesTransformed small-cell lung cancer (T-SCLC) has an extremely poor prognosis, and no remedies based on immunotherapy have been evaluated among T-SCLC patients. We retrospectively analysed the efficacy and safety of combining atezolizumab with chemotherapy for T-SCLC. MethodsForty-seven patients harbouring EGFR mutations who developed T-SCLC were enrolled. Eleven patients who used immunotherapy were defined as the I/O group, and the remaining 36 were defined as the Non-I/O group. Clinical characteristics, pathological data, and survival outcomes were collected. RNA sequencing and whole-exome sequencing (WES) were performed for in-depth analysis. ResultsAll patients received at least one line of EGFR-TKI before rebiopsy to confirm T-SCLC. Nine patients received atezolizumab-bevacizumab-carboplatin-paclitaxel (albumin-bound) (ABCP), and the remaining 2 received atezolizumab-etoposide-carboplatin (ECT) in the I/O group. The objective response rate was 73 % (8/11). The median progression-free survival (mPFS) of T-SCLC on post-transformation therapy with I/O group and Non-I/O group was 5.1 m and 4.1 m, respectively. The median post-T-SCLC overall survival of the I/O group was significantly longer than that Non-I/O group (20.2 m vs 7.9 m, P ＜ 0.01). T-SCLC harbouring EGFR L858R tended to be longer than EGFR 19del (mPFS: not reached vs 3.7 m, P = 0.11). Positive PD-L1 status was also associated with PFS benefits (mPFS: 6.0 m vs 3.7 m, P = 0.20). Furthermore, RNA sequencing revealed that expression of SFTPA1 is significantly higher in the durable clinical benefit group. WES showed that STC2 mutation is more frequently observed at the time-point immunotherapy acquired resistance. Combination therapy based on a PD-L1 inhibitor was well tolerated, and the safety profile was consistent with previously reported studies. ConclusionOur study first demonstrated that a PD-L1 inhibitor combined with chemotherapy ± bevacizumab could be a potential safe option for specific SCLC-transformed patients. Subsequent studies with more patients are essential to verify the efficacy and potential biomarkers.

368P A special Imaging pattern of bilateral diffuse metastases in advanced lung adenocarcinoma harboring EGFR mutations was associated with a favorable prognosis to EGFR-TKIs

Bilateral diffuse metastatic lung adenocarcinoma (BLDM-LUAD) is a special imaging pattern of lung adenocarcinoma (LUAD), characterized by diffuse, innumerable, small metastatic lesions evenly distributed in bilateral lungs. We retrospectively assessed survival outcomes and co-mutation characteristics of BLDM-LUAD patients harboring EGFR mutations who were treated with EGFR-TKIs.

Impact of T790M Mutation Status on Later-Line Osimertinib Treatment in Non-Small Cell Lung Cancer Patients.

Simple SummaryOsimertinib is a third-generation epidermal growth factor receptor tyrosine kinase inhibitor (EGFR-TKI) designed to overcome acquired T790M resistance mutations in non-small cell lung cancer (NSCLC). A total of 172 patients with advanced NSCLC treated with osimertinib following frontline EGFR-TKIs were retrospectively reviewed and divided into three groups based on the T790M status (positive, negative, or unknown T790M). The study confirmed the greater efficacy of later-line osimertinib for NSCLC with acquired T790M mutation than for NSCLC without acquired T790M mutation. Detection of the T790M mutation after frontline treatment (first- and second-generation EGFR-TKI) is crucial for prolonging the survival of NSCLC patients harboring EGFR mutation. Osimertinib may be considered an option for NSCLC with unknown T790M mutations, as a certain subpopulation may benefit from osimertinib.Background: Osimertinib is a third-generation epidermal growth factor receptor tyrosine kinase inhibitor (EGFR-TKI) designed to overcome acquired T790M resistance mutations in non-small cell lung cancer (NSCLC). However, the efficacy of osimertinib in patients without acquired T790M mutations has not been well studied. This study aimed to evaluate the efficacy of osimertinib in patients treated with first- and second-generation EGFR-TKIs followed by later-line osimertinib treatment. Patients: The clinical data and survival outcomes of 172 patients with advanced NSCLC treated with osimertinib following frontline EGFR-TKIs at Chang Gung Memorial Hospital from 2014 to 2018 were retrospectively reviewed. T790M mutations were detected using tissue sequencing and/or liquid biopsy. Results: A total of 172 EGFR-mutated NSCLC patients treated with frontline EGFR-TKI therapy followed by later-line osimertinib were enrolled in the current study and divided into three groups based on the T790M status (positive, negative, or unknown T790M). Patients with NSCLC harboring acquired T790M mutation treated with osimertinib had the best objective response rate (ORR) (52.6%, 25.0%, and 32.0%, p = 0.044), disease control rate (DCR) (79.3%, 41.7%, and 68.0%, p = 0.011), and progression-free survival (PFS, median PFS, 12.6, 3.1, 10.4 months, p = 0.001) among the three groups (positive, negative, and unknown T790M, respectively). However, a marked difference was found between positive and negative T790M mutations but not between positive and unknown T790M mutations. Univariate analysis was performed to identify potential prognostic factors for PFS in 172 patients treated with osimertinib. Lung metastasis (p < 0.001), brain metastasis (p < 0.009), number of metastatic sites (p < 0.001), PFS with frontline EGFR-TKIs (p = 0.03), and T790M status (p = 0.006) were identified as prognostic factors for PFS with osimertinib. Multivariate analysis showed that lung metastasis (p < 0.001) and PFS with frontline EGFR-TKIs and T790M status were independent prognostic factors. Conclusion: This study confirmed the greater efficacy of later-line osimertinib for NSCLC with acquired T790M mutation than for NSCLC without acquired T790M mutation. Detection of the T790M mutation after frontline treatment (first- and second-generation EGFR-TKI) is crucial for prolonging the survival of NSCLC patients harboring EGFR mutation. Osimertinib may be considered an option for NSCLC with unknown T790M mutations, as a certain subpopulation may benefit from osimertinib.

ARID1A deficiency reverses the response to anti-PD(L)1 therapy in EGFR-mutant lung adenocarcinoma by enhancing autophagy-inhibited type I interferon production

IntroductionEGFR mutations in non-small cell lung cancer (NSCLC) are associated with a poor response to immune checkpoint inhibitors (ICIs), and only 20% of NSCLC patients harboring EGFR mutations benefit from immunotherapy. Novel biomarkers or therapeutics are needed to predict NSCLC prognosis and enhance the efficacy of ICIs in NSCLC patients harboring EGFR mutations, especially lung adenocarcinoma (LUAD) patients, who account for approximately 40–50% of all NSCLC cases.MethodsAn ARID1A-knockdown (ARID1A-KD) EGFR-mutant LUAD cell line was constructed using lentivirus. RNA-seq and mass spectrometry were performed. Western blotting and IHC were used for protein expression evaluation. Effects of 3-MA and rapamycin on cells were explored. Immunofluorescence assays were used for immune cell infiltration examination.ResultsARID1A expression was negatively associated with immune cell infiltration and immune scores for ICIs in LUAD with EGFR mutations. In vitro experiments suggested that ARID1A-KD activates the EGFR/PI3K/Akt/mTOR pathway and inhibits autophagy, which attenuates the inhibition of Rig-I-like receptor pathway activity and type I interferon production in EGFR-mutant LUAD cells. In addition, 3-MA upregulated production of type I interferon in EGFR-mutant LUAD cells, with an similar effect to ARID1A-KD. On the other hand, rapamycin attenuated the enhanced production of type I interferon in ARID1A-KD EGFR-mutant LUAD cells. ARID1A function appears to influence the tumor immune microenvironment and response to ICIs.ConclusionARID1A deficiency reverses response to ICIs in EGFR-mutant LUAD by enhancing autophagy-inhibited type I interferon production.4p38v18Tik7_Gskdth_SehVideo

EP08.02-021 A Phase II Trial of Upfront Aumolertinib (HS-10296) plus Radiotherapy for EGFR Mutated Non-small-cell Lung Cancer Patients with Brain Metastases

Epidermal growth factor receptor tyrosine kinase inhibitor (EGFR-TKI) remains a standard treatment option for advanced non-small-cell lung cancer (NSCLC) patients harboring EGFR mutation. Aumolertinib, a third-generation EGFR-TKI, has shown to be highly effective and well-tolerated in first-line treatment for EGFR mutated advanced NSCLC patients with a median progression-free survival(PFS) reaching 19.3 months compared with 9.3 months for gefitinib. Radiotherapy, especially stereotactic radiosurgery(SRS) is proved to be a critical method for limited number of brain metastases.

EP08.02-120 MET Alterations at Presentation in NSCLC Patients Harboring EGFR Mutations and ALK, RET and ROS1 fusions

Although EGFR-mut and ALK, RET and ROS1 fusion-positive NSCLC patients are treated first-line with tyrosine kinase inhibitors (TKIs), some present intrinsic resistance and could benefit from combined treatments.To determine the frequency of MET gene amplification, MET mutations and MET mRNA high expression baseline in a large cohort of EGFR-mut and ALK, ROS1 and RET fusion-positive NSCLC patients; (ii) To analyze paired biopsies of EGFR and fusion positive patients showing MET amplification at progression to targeted therapies.

Mutant-Allele Tumor Heterogeneity, a Favorable Biomarker to Assess Intra-Tumor Heterogeneity, in Advanced Lung Adenocarcinoma.

BackgroundIntra-tumor heterogeneity (ITH) plays a vital role in drug resistance and recurrence of lung cancer. We used a mutant-allele tumor heterogeneity (MATH) algorithm to assess ITH and investigated its association with clinical and molecular features in advanced lung adenocarcinoma.MethodsTissues from 63 patients with advanced lung adenocarcinoma were analyzed by next-generation sequencing (NGS) using a panel targeting 520 cancer-relevant genes. We calculated the MATH values from NGS data and further investigated their correlation with clinical and molecular characteristics.ResultsAmong the 63 patients with advanced lung adenocarcinoma, the median value of MATH was 33.06. Patients with EGFR mutation had higher level of MATH score than those with wild-type EGFR status (P = 0.008). Patients with stage IV disease showed a trend to have a higher MATH score than those with stage III (P = 0.052). MATH was higher in patients with disruptive TP53 mutations than in those with non-disruptive mutations (P = 0.036) or wild-type sequence (P = 0.023), but did not differ between tumors with non-disruptive mutations and wild-type TP53 (P = 0.867). High MATH is associated with mutations in mismatch repair (MMR) pathway (P = 0.026) and base excision repair (BER) pathway (P = 0.008). In addition, MATH was found to have a positive correlation with tumor mutational burden (TMB) (Spearman ρ = 0.354; P = 0.004). In 26 patients harboring EGFR mutation treated with first generation EGFR TKI as single-agent therapy, the objective response rate was higher in the Low-MATH group than in the High-MATH group (75% vs. 21%; P = 0.016) and Low-MATH group showed a significantly longer progression-free survival than High-MATH group (median PFS: 13.7 months vs. 10.1 months; P = 0.024).ConclusionsFor patients with advanced lung adenocarcinoma, MATH may serve as a clinically practical biomarker to assess intratumor heterogeneity.