Wild-type Epidermal Growth Factor Receptor Research Articles

Real-world outcomes of chemotherapy for lung cancer patients undergoing hemodialysis: A multicenter retrospective cohort study (NEJ-042)

IntroductionMalignant tumors are the major cause of death in hemodialysis patients. Management of these patients remains challenging as there is no evidence that chemotherapy is beneficial, and a lack of information about actual clinical practice. MethodsThis multicenter retrospective study included hemodialysis patients who were diagnosed with lung cancer from January 2002 to June 2018. We reviewed their clinical information including patient characteristics associated with lung cancer and end-stage renal disease, regimen, efficacy and safety of chemotherapy, and outcomes. ResultsA total of 162 patients from 22 institutions in Japan were registered. Of 158 eligible patients, 91 received chemotherapy (80 as palliative chemotherapy and 11 as chemoradiotherapy) and 67 received best supportive care only regardless of cancer stage. In small cell lung cancer (SCLC) and non-small cell lung cancer (NSCLC) patients who received cytotoxic chemotherapy, the objective response rates (ORR) and median overall survival (OS) were 68.1 %, 12.3 months and 37.0 %, 8.5 months, respectively. The ORR and median OS in patients with EGFR-mutant NSCLC treated with EGFR-tyrosine kinase inhibitors (TKI) were 44.4 % and 38.6 months. The treatment-related adverse events (Grade 3 or higher) induced by cytotoxic chemotherapy were myelosuppression and febrile neutropenia; treatment-related death (TRD) was observed in one patient. TRD occurred in 3 of 18 patients who received EGFR-TKI. ConclusionChemotherapy should be considered for hemodialysis patients with EGFR-mutant NSCLC and SCLC. However, the survival benefits of chemotherapy for NSCLC patients with EGFR-wild type are unclear; physicians should carefully consider whether to offer chemotherapy to this patient subset.

Comparative Clinical Outcomes Between EGFR Ex20ins and Wildtype NSCLC Treated with Immune Checkpoint Inhibitors

IntroductionThe activity of immune checkpoint inhibitors (ICIs) in NSCLC harboring EGFR exon 20 insertion mutations (ex20ins) has not been closely examined due to the frequent exclusion of patients with EGFR mutations from large immunotherapy-based NSCLC trials. Patients and MethodsA real-world, retrospective study was conducted to compare outcomes of ICI-treated patients with EGFR ex20ins and wildtype NSCLC (wt-NSCLC; defined as EGFR and ALK test negative). Patients with advanced NSCLC from the Flatiron Health database (2015-2020) were included in the analysis. Real-world time to next therapy (rwTTNT) and overall survival (rwOS), stratified by ICI initiation line of therapy, were the prespecified primary and secondary endpoints, respectively. ResultsAmong 59 patients with EGFR ex20ins NSCLC and 5365 with wt-NSCLC, ICI treatment was received as first-line therapy in 25% and 39%, respectively. Patients with EGFR ex20ins had a 58% increased risk of shorter time to next-line therapy compared with wt-NSCLC (adjusted hazard ratio of 1.58 [95% confidence interval [CI], 1.2-2.1]; P = .0012). The median rwTTNT for first ICI line was 3.7 months (95% CI, 3.0-4.9) for EGFR ex20ins NSCLC compared with 5.8 months (95% CI, 5.6-6.0) for wt-NSCLC. No meaningful difference in rwOS between the groups was observed. ConclusionsICI therapy may be less effective for patients with EGFR ex20ins compared with wt-NSCLC. Consistent with prior data on exon 19 deletion and L858R substitution, tumors harboring ex20ins appear to be less responsive to immune checkpoint inhibition than wt-NSCLC.

Inhibition of Epidermal Growth Factor Receptor Signaling by Antisense Oligonucleotides as a Novel Approach to Epidermal Growth Factor Receptor Inhibition.

We report a novel method to inhibit epidermal growth factor receptor (EGFR) signaling using custom morpholino antisense oligonucleotides (ASOs) to drive expression of dominant negative mRNA isoforms of EGFR by ASO-induced exon skipping within the transmembrane (16) or tyrosine kinase domains (18 and 21). In vivo ASO formulations induced >95% exon skipping in several models of nonsmall cell lung cancer (NSCLC) and were comparable in efficacy to erlotinib in reducing colony formation, cell viability, and migration in EGFR mutant NSCLC (PC9). However, unlike erlotinib, ASOs maintained their efficacy in both erlotinib-resistant subclones (PC9-GR) and wild-type overexpressing EGFR models (H292), in which erlotinib had no significant effect. The most dramatic ASO-induced phenotype resulted from targeting the EGFR kinase domain directly, which resulted in maximal inhibition of phosphorylation of EGFR, Akt, and Erk in both PC9 and PC9GR cells. Phosphoproteomic mass spectrometry confirmed highly congruent impacts of exon 16-, 18-, and 21-directed ASOs compared with erlotinib on PC9 genome-wide cell signaling. Furthermore, EGFR-directed ASOs had no impact in EGFR-independent NSCLC models, confirming an EGFR-specific therapeutic mechanism. Further exploration of synergy of ASOs with existing tyrosine kinase inhibitors may offer novel clinical models to improve EGFR-targeted therapies for both mutant and wild-type NSCLC patients.

Discovery of BLU-945, a Reversible, Potent, and Wild-Type-Sparing Next-Generation EGFR Mutant Inhibitor for Treatment-Resistant Non-Small-Cell Lung Cancer.

While epidermal growth factor receptor (EGFR) tyrosine kinase inhibitors (TKIs) have changed the treatment landscape for EGFR mutant (L858R and ex19del)-driven non-small-cell lung cancer (NSCLC), most patients will eventually develop resistance to TKIs. In the case of first- and second-generation TKIs, up to 60% of patients will develop an EGFR T790M mutation, while third-generation irreversible TKIs, like osimertinib, lead to C797S as the primary on-target resistance mutation. The development of reversible inhibitors of these resistance mutants is often hampered by poor selectivity against wild-type EGFR, resulting in potentially dose-limiting toxicities and a sub-optimal profile for use in combinations. BLU-945 (compound 30) is a potent, reversible, wild-type-sparing inhibitor of EGFR+/T790M and EGFR+/T790M/C797S resistance mutants that maintains activity against the sensitizing mutations, especially L858R. Pre-clinical efficacy and safety studies supported progression of BLU-945 into clinical studies, and it is currently in phase 1/2 clinical trials for treatment-resistant EGFR-driven NSCLC.

A rare case of Exon 19 deletion transforming to Exon 20 insertion in a case of adenocarcinoma of lung

Epidermal growth factor receptor (EGFR) gene mutations play an important role in the presentation, prognosis, and management of non-small cell lung cancer (NSCLC) patients. Several clinical studies claimed the incidence of EGFR Exon 20 insertion mutations in NSCLC and have similar clinical characteristics to those with common EGFR mutations but poorer prognosis. Insertion mutations within the Exon 20 of the EGFR gene are typically located after the C-helix of the tyrosine kinase to result in the domain of EGFR and have been reported to increase the kinase activity of the protein. This eventually leads to the ligand-independent activation of several downstream pathways such as mitogen activated protein kinase (MAPK) and phosphatidylinositol-3-kinase (Pi3K)-(mTOR) mammalian target of rapamycin pathways, which are involved in several cellular processes such as cell proliferation, metastasis, and migration while preventing apoptosis. Thus, EGFR exon insertion mutations are gain of function mutations. Specific EGFR and frame-in insertions occur in 3–7% of NSCLC and are known to predict primary resistance to treatment with all clinically available EGFR-tyrosine kinase inhibitors (TKIs). Many clinical and preclinical studies have reported significant antitumor activity with various first and second-generation EGFR TKIs such as Erlotinib, Gefitinib, and Afatinib and have led to prolonged survival in EGFR mutated patients, as compared to wild-type EGFR tumors with chemotherapy. In addition, third-generation EGFR TKIs, such as Osimertinib, have shown encouraging results in metastatic NSCLC patients harboring EGFR mutations including EGFR, p. Thr790Met-mutations, that have shown to confer resistance to first and second-generation EGFR TKIs and who have progressed on prior TKI therapy. Drugs such as Afatinib, Dacomitinib, Erlotinib, Gefitinib, and Osimertinib have already gained FDA approval for use in EGFR-mutated metastatic NSCLC patients. Here, we report the case of a 47-year-old man who is a non-smoker with an EGFR Exon 19 positive NSCLC treated with Gefitinib developed an EGFR Exon 20 insertion positive brain metastasis initiated on Afatinib as the targeted therapy and responded well to the treatment.

Diverse Mechanisms of Resistance against Osimertinib, a Third-Generation EGFR-TKI, in Lung Adenocarcinoma Cells with an EGFR-Activating Mutation.

Osimertinib, a third-generation epidermal growth factor receptor (EGFR) tyrosine kinase inhibitor (TKI), is used as a first-line treatment for patients with EGFR-mutant non-small cell lung cancer (NSCLC). However, the mechanisms underlying its anticancer activity, particularly the subsequent development of acquired resistance, are unclear. Herein, we investigated the mechanisms underlying the development of osimertinib resistance by treating NSCLC PC-9 cells (harboring an EGFR-activating mutation) with osimertinib, thereby developing five resistant cell lines, i.e., AZDR3, AZDR6, AZDR9, AZDR11, and AZDR14. The amplification of wild-type EGFR in AZDR3 cells and wild-type EGFR and KRAS in AZDR6 cells was also studied. AZDR3 cells showed dependence on EGFR signaling, in addition to afatinib sensitivity. AZDR9 cells harboring KRASG13D showed sensitivity to MEK inhibitors. Furthermore, combination treatment with EGFR and IGF1R inhibitors resulted in attenuated cell proliferation and enhanced apoptosis. In AZDR11 cells, increased Bim expression could not induce apoptosis, but Bid cleavage was found to be essential for the same. A SHP2/T507K mutation was also identified in AZDR14 cells, and, when associated with GAB1, SHP2 could activate ERK1/2, whereas a SHP2 inhibitor, TNO155, disrupted this association, thereby inhibiting GAB1 activation. Thus, diverse osimertinib resistance mechanisms were identified, providing insights for developing novel therapeutic strategies for NSCLC.

Radiomic Signatures for Predicting EGFR Mutation Status in Lung Cancer Brain Metastases.

BackgroundLung cancer is the most common primary tumor metastasizing to the brain. A significant proportion of lung cancer patients show epidermal growth factor receptor (EGFR) mutation status discordance between the primary cancer and the corresponding brain metastases, which can affect prognosis and therapeutic decision-making. However, it is not always feasible to obtain brain metastases samples. The aim of this study was to establish a radiomic model to predict the EGFR mutation status of lung cancer brain metastases.MethodsData from 162 patients with resected brain metastases originating from lung cancer (70 with mutant EGFR, 92 with wild-type EGFR) were retrospectively analyzed. Radiomic features were extracted using preoperative brain magnetic resonance (MR) images (contrast-enhanced T1-weighted imaging, T1CE; T2-weighted imaging, T2WI; T2 fluid-attenuated inversion recovery, T2 FLAIR; and combinations of these sequences), to establish machine learning-based models for predicting the EGFR status of excised brain metastases (108 metastases for training and 54 metastases for testing). The least absolute shrinkage selection operator was used to select informative features; radiomics models were built with logistic regression of the training cohort, and model performance was evaluated using an independent test set.ResultsThe best-performing model was a combination of 10 features selected from multiple sequences (two from T1CE, five from T2WI, and three from T2 FLAIR) in both the training and test sets, resulting in classification area under the curve, accuracy, sensitivity, and specificity values of 0.85 and 0.81, 77.8% and 75.9%, 83.7% and 73.1%, and 73.8% and 78.6%, respectively.ConclusionsRadiomic signatures integrating multi-sequence MR images have the potential to noninvasively predict the EGFR mutation status of lung cancer brain metastases.

Discovery of potent and selective HER2 inhibitors with efficacy against HER2 exon 20 insertion-driven tumors, which preserve wild-type EGFR signaling.

Oncogenic alterations in human epidermal growth factor receptor 2 (HER2) occur in approximately 2% of patients with non-small cell lung cancer and predominantly affect the tyrosine kinase domain and cluster in exon 20 of the ERBB2 gene. Most clinical-grade tyrosine kinase inhibitors are limited by either insufficient selectivity against wild-type (WT) epidermal growth factor receptor (EGFR), which is a major cause of dose-limiting toxicity or by potency against HER2 exon 20 mutant variants. Here we report the discovery of covalent tyrosine kinase inhibitors that potently inhibit HER2 exon 20 mutants while sparing WT EGFR, which reduce tumor cell survival and proliferation in vitro and result in regressions in preclinical xenograft models of HER2 exon 20 mutant non-small cell lung cancer, concomitant with inhibition of downstream HER2 signaling. Our results suggest that HER2 exon 20 insertion-driven tumors can be effectively treated by a potent and highly selective HER2 inhibitor while sparing WT EGFR, paving the way for clinical translation.

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.

Structural dynamics and kinase inhibitory activity of three generations of tyrosine kinase inhibitors against wild-type, L858R/T790M, and L858R/T790M/C797S forms of EGFR

Mutations in the tyrosine kinase domain of epidermal growth factor receptor (EGFR), including L858R/T790M double and L858R/T790M/C797S triple mutations, are major causes of acquired resistance towards EGFR targeted drugs. In this work, a combination of comprehensive molecular modeling and in vitro kinase inhibition assay was used to unravel the mutational effects of EGFR on the susceptibility of three generations of EGFR tyrosine kinase inhibitors (erlotinib, gefitinib, afatinib, dacomitinib, and osimertinib) in comparison with the wild-type EGFR. The binding affinity of all studied inhibitors towards the double and triple EGFR mutations was in good agreement with the experimental data, ranked in the order of osimertinib > afatinib > dacomitinib > erlotinib > gefitinib. Three hot-spot residues at the hinge region (M790, M793, and C797) were involved in the binding of osimertinib and afatinib, enhancing their inhibitory activity towards mutated EGFRs. Both double and triple EGFR mutations causing erlotinib and gefitinib resistance are mainly caused by the low number of H-bond occupations, the low number of surrounding atoms, and the high number of water molecules accessible to the enzyme active site. According to principal component analysis, the molecular complexation of osimertinib against the two mutated EGFRs was in a closed conformation, whereas that against wild-type EGFR was in an open conformation, resulting in drug resistance. This work paves the way for further design of the novel EGFR inhibitors to overcome drug resistance mechanisms.

State-of-the-Art Molecular Oncology of Lung Cancer in Taiwan.

Lung cancers are life-threatening malignancies that cause great healthcare burdens in Taiwan and worldwide. The 5-year survival rate for Taiwanese patients with lung cancer is approximately 29%, an unsatisfactorily low number that remains to be improved. We first reviewed the molecular epidemiology derived from a deep proteogenomic resource in Taiwan. The nuclear factor erythroid 2-related factor 2 (NRF2)antioxidant mechanism was discovered to mediate the oncogenesis and tumor progression of lung adenocarcinoma. Additionally, DNA replication, glycolysis and stress response are positively associated with tumor stages, while cell-to-cell communication, signaling, integrin, G protein coupled receptors, ion channels and adaptive immunity are negatively associated with tumor stages. Three patient subgroups were discovered based on the clustering analysis of protein abundance in tumors. The first subgroup is associated with more advanced cancer stages and visceral pleural invasion, as well as higher mutation burdens. The second subgroup is associated with EGFR L858R mutations. The third subgroup is associated with PI3K/AKT pathways and cell cycles. Both EGFR and PI3K/AKT signaling pathways have been shown to induce NRF2 activation and tumor cell proliferation. We also reviewed the clinical evidence of patient outcomes in Taiwan given various approved targeted therapies, such as EGFR-tyrosine kinase inhibitors and anaplastic lymphoma kinase (ALK)inhibitors, in accordance with the patients’ characteristics. Somatic mutations occurred in EGFR, KRAS, HER2 and BRAF genes, and these mutations have been detected in 55.7%, 5.2%, 2.0% and 0.7% patients, respectively. The EGFR mutation is the most prevalent targetable mutation in Taiwan. EML4-ALK translocations have been found in 9.8% of patients with wild-type EGFR. The molecular profiling of advanced NSCLC is critical to optimal therapeutic decision-making. The patient characteristics, such as mutation profiles, protein expression profiles, drug-resistance profiles, molecular oncogenic mechanisms and patient subgroup systems together offer new strategies for personalized treatments and patient care.

Association Between EGFR and ALK Mutation Status on Patient-Reported Symptoms After Palliative Radiation for Bone Pain in NSCLC

IntroductionAfter palliative radiotherapy for bone metastases from NSCLC, up to 30% of patients may derive no symptomatic benefit, and there are a lack of biological predictors for this. The purpose was to investigate whether EGFR and ALK genetic rearrangements were associated with greater rates of pain response to palliative radiotherapy. MethodsPatients were identified from a prospectively collected patient-reported outcomes database for all patients with lung cancer treated with conventional palliative radiotherapy for bone metastases from 2013 to 2016 in the province of British Columbia. Patients were divided on the basis of mutational status into the following: EGFR and ALK wild type (WT), EGFR mutation present (EGFR+), or ALK mutation present (ALK+). Patient-reported outcomes of global pain severity were collected before and after radiotherapy and on an ordinal scale of 0 to 4, with 0 representing no bone pain and 4 representing the maximal possible bone pain. The primary outcome was the rate of partial pain response (any improvement in score), and the secondary outcome was the rate of complete pain response (final pain score of 0). Stepwise, multivariable logistic analysis was used to compare response rates between treatment courses for different mutational statuses. ResultsThe final cohort consisted of 388 treatment courses for 329 unique patients. For the WT, EGFR+, and ALK+ groups, there were 180, 63, and nine treatment courses, respectively. There were 92 patients with no ALK and EGFR testing. The most common treatment fractionations were 8 Gy in one fraction (188 of 388) and 20 Gy in five fractions (160 of 388), and use of multifraction radiotherapy did not differ between mutation status groups (p = 0.3). Partial pain response rates were as follows: WT 63%, EGFR+ 75%, and ALK+ 78%. On multivariable analysis, rates of partial response were higher for EGFR+ (OR = 5.4, p < 0.001) and for ALK+ (OR = 12.8, p = 0.008) in comparison to WT. Complete response rates were as follows: WT 20.5%, EGFR+ 35%, and ALK+ 67%. On multivariable analysis, complete response was not significantly increased in EGFR+ compared with WT (OR = 1.6, p = 0.127). ALK+ mutation status was associated with a higher rate of complete response compared with WT (OR = 5.2, p = 0.031). ConclusionsThere was an association between EGFR+ and ALK+ tumors and increased rates of partial pain response to palliative radiotherapy.

S645C Point Mutation Suppresses Degradation of EGFR to Promote Progression of Glioblastoma.

BackgroundThe tightly controlled activity of EGFR is important for the homeostasis of self-renewal of human tissue. Mutations in the extracellular domain of EGFR are frequent and function as a novel mechanism for oncogenic EGFR activation in GBM, and impact the response of patients to small-molecule inhibitors.MethodsWe constructed glioblastoma cell lines stably expressing wild-type EGFR and the mutant of EGFR S645C. We detected cell growth in vitro and in vivo. We evaluated the anti-tumor activity and effectiveness of gefitinib and osimertinib in cells.ResultsIn the present study, we identified an oncogenic substituted mutation of EGFR—S645C. The mutation can promote the proliferation and colony formation of glioblastoma in vitro and in vivo. Mechanistically, the EGFR S645C mutation potentially changes the formation of hydrogen bonds within dimerized EGFR and inhibits the degradation of EGFR to prolong downstream signaling. The mutation induces resistance to gefitinib but presents an opportunity for osimertinib treatment.ConclusionThe study indicated a novel oncogenic mutation and advises on the precise treatment of individual patients with the EGFR S645C mutation.

Efficacy of Atezolizumab for Advanced Non-Small Cell Lung Cancer Based on Clinical and Molecular Features: A Meta-Analysis.

ObjectiveAtezolizumab is becoming a significant therapy for non-small cell lung cancer (NSCLC), but its efficacy needs to be further improved. The aims of this study are to clarify the potency of atezolizumab-based therapy in advanced NSCLC patients with different clinical and molecular features, and to choose a better therapeutic regimen of atezolizumab to achieve more precise treatment in immunotherapy.MethodsRandomized clinical trials (RCTs) in the Cochrane Library, PubMed, Embase Science Direct, and Google Scholar, together with major oncology conferences that compared atezolizumab with chemotherapy-based treatment for individuals with advanced NSCLC published prior to February 2022, were searched. Studies, bias risk assessment, and data extraction were selected by two independent authors. We extracted the basic features of the included studies, together with the 95% confidence interval (CI) and hazard ratios (HRs), from all patients and subgroups. The combined treatment data were assessed using the inverse variance weighting method.ResultsSeven RCTs including 4,859 patients were included. Our meta-analysis findings indicated that atezolizumab substantially enhanced OS (HR 0.82; 95% CI, 0.77–0.88; p < 0.00001) and PFS (HR 0.72; 95% CI, 0.61–0.85; p < 0.0001) in patients with advanced NSCLC compared with chemotherapy-based treatment. Atezolizumab substantially enhanced OS in patients aged <65 years old and 65–74 years old, those with wild-type EGFR, those without liver metastases, active or previous smokers, white patients and those with TC3 or IC3, TC2/3 or IC2/3, TC1/2/3 or IC1/2/3, and TC0 and IC0, but not in patients aged ≥75 years, never smokers, those with liver metastases, those with EGFR mutant, Asians, Black or African Americans, or those with TC1/2 or IC1/2. Patients with advanced NSCLC who received atezolizumab showed OS improvement regardless of sex (male or female), histological type (non-squamous or squamous NSCLC), performance status (0 or 1), and line of treatment (1st-line therapy or ≥2nd-line therapy). Subgroup analysis revealed that male individuals, those with non-squamous NSCLC, those with PS 1, active or previous smokers, and those with wild-type EGFR, TC3 or IC3, and TC1/2/3 or IC1/2/3 achieved OS benefit from atezolizumab treatment not related to the treatment line and treatment regimen.ConclusionsAge group, smoking history, liver metastasis status, EGFR mutation status, race, and PD-L1 expression can be used to predict the potency of atezolizumab and provide a better treatment regimen for patients with advanced NSCLC to achieve accurate and personalized treatment.

PET/CT Radiomic Features: A Potential Biomarker for EGFR Mutation Status and Survival Outcome Prediction in NSCLC Patients Treated With TKIs.

BackgroundsEpidermal growth factor receptor (EGFR) mutation profiles play a vital role in treatment strategy decisions for non–small cell lung cancer (NSCLC). The purpose of this study was to evaluate the predictive efficacy of baseline 18F-FDG PET/CT-based radiomics analysis for EGFR mutation status, mutation site, and the survival benefit of targeted therapy.MethodsA sum of 313 NSCLC patients with pre-treatment 18F-FDG PET/CT scans and genetic mutations detection were retrospectively studied. Clinical and PET metabolic parameters were incorporated into independent predictors of determining mutation status and mutation site. The dataset was randomly allocated into the training and the validation sets in a 7:3 ratio. Three-dimensional (3D) radiomics features were extracted from each PET- and CT-volume of interests (VOI) singularly, and then a radiomics signature (RS) associated with EGFR mutation profiles is built by feature selection. Three different prediction models based on support vector machine (SVM), decision tree (DT), and random forest (RF) classifiers were established. Furthermore, nomograms for estimation of overall survival (OS) and progression-free survival (PFS) were established by integrating PET/CT radiomics score (Rad-score), metabolic parameters, and clinical factors. Predictive performance was assessed by the receiver operating characteristic (ROC) analysis and the calibration curve analysis. The decision curve analysis (DCA) was applied to estimate and compare the clinical usefulness of nomograms.ResultsThree hundred thirteen NSCLC patients were classified into a training set (n=218) and a validation set (n=95). Multivariate analysis demonstrated that SUVmax and sex were independent indicators of EGFR mutation status and mutation site. Eight CT-derived RS, six PET-derived RS, and two clinical factors were retained to develop integrated models, which exhibited excellent ability to distinguish between EGFR wild type (EGFR-WT), EGFR 19 mutation type (EGFR-19-MT), and EGFR 21 mutation type (EGFR-21-MT). The SVM model outperformed the RF model and the DT model, yielding training area under the curves (AUC) of EGFR-WT, EGFR-19-WT, and EGFR-21-WT, with 0.881, 0.851, and 0.849, respectively, and validation AUCs of 0.926, 0.805 and 0.859, respectively. For prediction of OS, the integrated nomogram is superior to the clinical nomogram and the radiomics nomogram, with C-indexes of 0.80 in the training set and 0.83 in the validation set, respectively.ConclusionsThe PET/CT-based radiomics analysis might provide a novel approach to predict EGFR mutation status and mutation site in NSCLC patients and could serve as useful predictors for the patients’ survival outcome of targeted therapy in clinical practice.

Abstract 3342: Discovery of potent and selective next-generation EGFR inhibitors with activity against single, double, and triple mutant EGFR variants including T790M and C797S

Abstract Introduction: EGFR activating mutations are observed in 10-50% of NSCLC patients and the common mutations (L858R [L] and exon 19 deletions [D]) are initially sensitive to first-, second-, and third-generation EGFR inhibitors (eg erlotinib [1G], afatinib [2G], and osimertinib [3G], respectively). However, on-target resistance is observed in a substantial percentage of patients, with T790M (T) and C797S (C) observed most frequently (post-1G/2G and post-3G, respectively). We set out to identify a next-generation inhibitor with 1) potent activity against all 8 major single (L and D), double (LT, DT, LC, DC), and triple (LTC, DTC) mutant variants, 2) selectivity over wild type (WT) EGFR, and 3) ability to penetrate the central nervous system (CNS). Experimental Procedures: Drug activity was determined by assessing effects in kinase assays and on tumor and BaF3 cell lines expressing WT or mutant forms of EGFR. For efficacy studies, mice were dosed orally once daily at doses that did not exceed the maximum tolerated dose. Results: Here we report the identification of a series of compounds with potent and selective in vitro and in vivo activity against all major classes of EGFR activating and resistance mutations and with selectivity over WT EGFR. A representative member from this series (Cmpd A) potently inhibits the kinase activity of EGFR L, LT, and LTC variants with IC50s ≤0.2 nM, compared to IC50s for osimertinib of 0.4, 0.2, and 360 nM respectively. In engineered BaF3 cells, Cmpd A inhibited viability of all 8 EGFR single, double, and triple mutant variants with IC50s &amp;lt;7 nM, while erlotinib was inactive against LT, DT, LTC, and DTC, and osimertinib was inactive against LC, DC, LTC, and DTC. Cmpd A inhibited the activity of all 8 variants with 7- to 46-fold selectivity over WT EGFR, which compared favorably to the 7- to 10-fold selectivity erlotinib exhibited for L and D. In vivo, Cmpd A (30 mg/kg QD) induced tumor regression, or inhibited tumor growth by at least 90%, in models containing EGFR single (L), double (LT), and triple (LTC and DTC) mutant variants. Studies to examine the CNS penetration of compounds are underway. Conclusions: We have identified a series of next-generation EGFR inhibitors with potent in vitro and in vivo activity against single, double, and triple mutant EGFR variants including T790M and C797S. Citation Format: Wei-Sheng Huang, Sara Nadworny, Narayana Narasimhan, Charles J. Eyermann, David C. Dalgarno, Victor M. Rivera, William C. Shakespeare. Discovery of potent and selective next-generation EGFR inhibitors with activity against single, double, and triple mutant EGFR variants including T790M and C797S [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 3342.

Abstract 5461: H002: A wide spectrum, highly selective fourth-generation EGFR inhibitor overcoming resistance harboring C797S mutation in NSCLC

Abstract BACKGROUND: Resistance to epidermal growth factor receptor (EGFR) tyrosine kinase inhibitors (TKIs) is a major challenge in non-small cell lung cancer (NSCLC) treatment. EGFR activating mutations, such as exon 19 deletions (Del19) and L858R substitution, have been reported in 10-50% of patients with NSCLC. Although these patients respond well to early generations of TKIs, acquired resistance by mechanisms such as T790M mutation compromises their efficacy. Recently, the C797S mutation in combination with Del19 or L858R, and with T790M, has emerged as one of the most common mechanisms underlying on-target resistance to a third generation EGFR TKI, osimertinib. We are developing a fourth-generation EGFR inhibitor, H002, with a wide spectrum and high selectivity to address the growing unmet needs in NSCLC patients harboring C797S mutation. METHODS: H002’s selectivity was assessed by KINOMEscan against more than 400 human kinases. A panel of 44 kinases was further evaluated to enable early identification of off-target effect. In vitro and in vivo anti-tumor efficacy was determined in drug-resistant mutant cell lines, CDX and PDX models. Single mutants (Del or L858R), double mutants (Del/T790M or L858R/T790M) and triple mutants (Del/T790M/C797S or L858R/T790M/C797S) as well as wild type EGFR were assessed. Drug metabolism and pharmacokinetic (DMPK) properties were further assessed. H002’s safety profile was evaluated in rats and beagle dogs, and by hERG potassium channel assay. Acute toxicity, and repeated dose GLP toxicity studies were also conducted in IND-enabling studies. RESULTS: High kinase selectivity and very low off-target effects were demonstrated by kinome-wide profiling and safety screening. H002 was highly active against all forementioned single, double or triple EGFR mutants (IC50 &amp;lt; 5 nM), and highly selective against wild type EGFR. H002 also exhibited potent anti-tumor effects in a dose-dependent manner in various CDX and PDX models. Excellent PK properties were observed in rats and beagle dogs with bioavailability over 70%. H002 was shown to cross the blood-brain barrier post i.g. administration in rats. No adverse effects of respiratory, cardiovascular and central nervous system were observed in safety studies. Repeated-dose toxicity studies only showed EGFR-related adverse reactions, such as gastrointestinal and liver toxicity, with high safety margin over 10-folds. CONCLUSION: H002 has been demonstrated as a promising next generation EGFR inhibitor, with high selectivity, a wide spectrum and potent anti-tumor activity against various EGFR activating mutations, favorable DMPK and safety profiles. It will be further developed as a fourth-generation EGFR inhibitor to overcome drug resistance in NSCLC. Citation Format: Wei Huang, Lin Zhu, Xiaoe Yan, Xin Huang, Jia Hao, Shan Li, Xiangyu Li, Zhiming Chen, Yunchuan Jia, Haibo Li, Jianming Zhang, Xianming Deng, Caihong Yun. H002: A wide spectrum, highly selective fourth-generation EGFR inhibitor overcoming resistance harboring C797S mutation in NSCLC [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 5461.

Abstract LB525: Discovery and characterization of ABSK111, a selective, CNS-penetrable, and broad-spectrum EGFR inhibitor targeting exon20 insertion, atypical and extracellular mutations

Abstract Epidermal growth factor receptor (EGFR) exon20 insertion mutations and atypical mutations account for about 9% and 20% of EGFR-mutated non-small cell lung cancer (NSCLC), respectively. Currently approved EGFR tyrosine kinase inhibitors (TKIs) have shown efficacy in NSCLC patients with exon20 insertion and atypical mutations, but with limited overall response and high rate of EGFR-related severe adverse events. This may be associated with the inhibition of wild-type (WT) EGFR. ABSK111 is a highly potent, selective, and CNS-penetrable EGFR inhibitor, targeting multiple EGFR and HER2 mutations, including exon20 insertion, atypical, and extracellular mutations. Here we describe the preclinical in vitro and in vivo characterization of ABSK111. ABSK111 potently inhibited the proliferation of BA/F3 cell lines harboring EGFR exon20, atypical and extracellular mutations with higher selectivity for WT EGFR than currently approved EGFR TKIs. ABSK111 also suppressed HER2 atypical and exon20 mutations. Further, ABSK111 potently blocked the phosphorylation of EGFR exon20 insertion mutations and EGFR variant III in BA/F3 cell lines, with less inhibition of WT EGFR signal than the approved TKIs. Moreover, pharmacokinetic and pharmacodynamic studies demonstrated sustained and exposure-dependent suppression of p-ERK in tumor tissue following a single oral dose of ABSK111. Finally, ABSK111 showed dose-dependent anti-tumor activity in BA/F3 tumor models with EGFR exon20 insertion mutations and EGFR variant III without significant body weight loss. Pharmacodynamic analysis of endpoint samples from efficacy study showed sustained inhibition of p-ERK, which was superior to the approved exon20 insertion inhibitor mobocertinib. Taken together, these results demonstrate the ability of ABSK111 to inhibit a broad spectrum of EGFR and HER2 mutations, including exon20 insertions, atypical and extracellular mutations, while sparing the WT form of EGFR. In addition to the application in NSCLC, the activity against EGFR extracellular mutations and the ability to penetrate into brain suggest the application of ABSK111 in glioblastoma multiforme (GBM). Citation Format: Cheng Dai, Juan Peng, Fei Yang, Haibing Deng, Yuan Zhao, Hongping Yu, Yaochang Xu, Zhui Chen, Shuqun Yang. Discovery and characterization of ABSK111, a selective, CNS-penetrable, and broad-spectrum EGFR inhibitor targeting exon20 insertion, atypical and extracellular mutations [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr LB525.

Abstract LB042: Sorting nexin-dependent therapeutic targeting of oncogenic epidermal growth factor receptor

Abstract Overexpression and/or overactivation of the Epidermal Growth Factor Receptor (EGFR) is oncogenic in several tumor types yet targeting the kinase domain of wildtype EGFR has had limited success. EGFR has numerous kinase-independent roles, one of which is accomplished through the Sorting Nexin-dependent retrotranslocation of EGFR to the nucleus, which is observed in some metastatic cancers and therapeutically resistant disease. Here, we have utilized the BAR domain of Sorting Nexin 1 to create a peptide-based therapeutic (cSNX1.3) that promotes cell death in EGFR-expressing cancer. We evaluated the efficacy of cSNX1.3 in tumor-bearing WAP-TGFα transgenic mice (an EGFR-dependent model of breast cancer), where cSNX1.3 treatment resulted in significant tumor regression without observable toxicity. Evaluation of remaining tumor tissues found evidence of increased PARP cleavage, suggesting apoptotic tumor cell death. To evaluate the mechanism of action for cSNX1.3, we found that cSNX1.3 binds the C-terminus of the EGFR kinase domain at an interface site opposite the ATP binding domain with a K d of ~4.0 µM. In vitro analysis found that cSNX1.3 inhibits both long-term EGF-dependent AKT and ERK activation, as well as nuclear localization of EGFR. To determine specificity, we evaluated cancer cell lines expressing wildtype EGFR (MDA-MB-468, BT20 and A549), mutant EGFR (H1975) and non-transformed lines (CHO and MCF10A). Only transformed lines expressing wildtype EGFR responded to cSNX1.3, while mutant EGFR and normal cells responded better to the EGFR kinase inhibitor (Sapitinib). Phenotypically, cSNX1.3 inhibits EGF-, NRG-, and HGF-dependent migration, but not HA-dependent migration. Together, these data indicate that targeting retrotranslocation of EGFR may be a potent therapeutic for RTK-active cancer. Citation Format: Ben Atwell. Sorting nexin-dependent therapeutic targeting of oncogenic epidermal growth factor receptor [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr LB042.

Abstract 5457: QLH11811, a selective 4th-generation EGFR inhibitor for osimertinib-resistant EGFR-mutant NSCLC

Abstract Background: The 3rd-generation epidermal growth factor receptor (EGFR) tyrosine kinase inhibitors (TKI), like osimertinib, provide marked clinical benefit for EGFR-mutant non-small cell lung cancer (NSCLC) patients with extended overall survival vs former EGFR TKIs (e.g., gefitinib). Approximate 10%-24% of NSCLC patients acquired C797S mutation when treated with osimertinib. Unfortunately, limited treatments are available for patients after osimertinib resistance. QLH11811 is a new generation EGFR TKI designed to target the EGFR with ex19del/L858R/T790M/C797S mutations. Here, we disclosed its preclinical data to support its clinical development in EGFR-mutant NSCLC. Methods: The inhibitory activity of QLH11811 on mutated and wild-type EGFR was tested in engineered cell lines and patient-derived organoid (PDO). The in vivo antitumor activity of QLH11811 was evaluated in the patient-derived xenograft (PDX) model with cis EGFR ex19del/T790M/C797S triple mutations, and the H1975 (cis EGFR L858R/T790M/C797S and cis EGFR ex19del/T790M/C797S), PC-9 (EGFR ex19del), and Ba/F3 (EGFR ex19del/C797S) cell line-derived xenograft (CDX) models. The pharmacokinetic (PK) profile was investigated in animals, and the human PK profile was projected using allometric scaling method. Results: QLH11811 displayed potent anti-proliferation activity against Ba/F3 (EGFR ex19del/T790M/C797S, L858R/T790M/C797S, ex19del/C797S, or L858R/C797S), PC-9 (EGFR ex19del/T790M/C797S), H1975 (EGFR L858R/T790M/C797S, L858R/T790M), H3255 (L858R) and HCC827 (ex19del) with IC50 of 2.6, 3.1, 2.4, 4.1, 51, 50, 27, 21, and 11 nM, respectively. QLH11811 also showed excellent selectivity when compared the above values with its IC50 against Ba/F3 (EGFR wild-type, 61 nM) and A431 (EGFR wild-type, 440nM). QLH11811 demonstrated excellent inhibitory activities against seven osimertinib-resistant PDO models. Daily oral QLH11811 significantly inhibited tumor growth at all doses tested (P &amp;lt;0.001) in the PDX model, the H1975, PC-9, and Ba/F3 CDX models. QLH11811 had good PK profile in mice, rats, dogs, and monkeys, with the absolute bioavailability at 71%, 29%, 80% and 42%. The human PK parameters were obtained by allometric scaling method, and the efficacious dose in human was projected to 103 mg, daily. Conclusion: The in vitro and in vivo preclinical data demonstrated QLH11811 is a highly potent and selective 4th-generation EGFR TKI with activity against the osimertinib-resistant NSCLC with EGFR C797S mutation. The preclinical PK data supported the efficacious dose of QLH11811 in human would be 103 mg. Citation Format: Shansong Zheng, Wei Deng, Qingmei Zheng, Yingying Yang, Na Li, Tan Pang, Xueying Feng, Simon Taylor, Lina Ma, Yaqiong Wu, Ziwei Zhao. QLH11811, a selective 4th-generation EGFR inhibitor for osimertinib-resistant EGFR-mutant NSCLC [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 5457.