Generation Epidermal Growth Factor Receptor Tyrosine Kinase Inhibitors Research Articles

Biochemical analysis of EGFR exon20 insertion variants insASV and insSVD and their inhibitor sensitivity

Somatic mutations in the epidermal growth factor receptor (EGFR) are a major cause of non-small cell lung cancer. Among these structurally diverse alterations, exon 20 insertions represent a unique subset that rarely respond to EGFR tyrosine kinase inhibitors (TKIs). Therefore, there is a significant need to develop inhibitors that are active against this class of activating mutations. Here, we conducted biochemical analysis of the two most frequent exon 20 insertion variants, V769_D770insASV (insASV) and D770_N771insSVD (insSVD) to better understand their drug sensitivity and resistance. From kinetic studies, we found that EGFR insASV and insSVD are similarly active, but have lower Km, ATP values compared to the L858R variant, which contributes to their lack of sensitivity to 1st-3rd generation EGFR TKIs. Biochemical, structural, and cellular studies of a diverse panel of EGFR inhibitors revealed that the more recently developed compounds BAY-568, TAS6417, and TAK-788 inhibit EGFR insASV and insSVD in a mutant-selective manner, with BAY-568 being the most potent and selective versus wild-type (WT) EGFR. Cocrystal structures with WT EGFR reveal the binding modes of each of these inhibitors and of poziotinib, a potent but not mutantselective inhibitor, and together they define interactions shared by the mutant-selective agents. Collectively, our results show that these exon20 insertion variants are not inherently inhibitor resistant, rather they differ in their drug sensitivity from WT EGFR. However, they are similar to each other, indicating that a single inhibitor should be effective for several of the diverse exon 20 insertion variants.

Assessing platelet-lymphocyte ratio in EGFR-mutated non-small cell lung cancer patients treated with tyrosine kinase inhibitors: An analysis across TKI generations.

Introduction : The prognostic utility of laboratory markers in patients with non-small cell lung cancer (NSCLC) harboring EGFR mutations treated with tyrosine kinase inhibitors (TKIs) is an ongoing area of research. The utility of the platelet-lymphocyte ratio (PLR) in patients treated with osimertinib is undetermined. Methods : 151 patients treated with EGFR TKIs in Los Angeles were grouped into one of two groups according to generation of TKI. Differences in progression free survival (PFS) by stratification by PLR was determined using Kaplan-Meier analysis. Differences in median change in laboratory markers by generation of TKI was analyzed using Mann-Whitney tests. Cox Hazard Regression was used to perform multivariate analysis. Results : Median PFS of those managed with 1st or 2nd generation TKIs was significantly lower in patients with a PLR ≥ 180 (10.5 months) compared to those with PLR < 180 (16.6 months, p = 0.0163). Median PFS was comparable in those treated with osimertinib regardless of PLR. Patients managed with osimertinib had a significant decrease in absolute lymphocyte count (ALC) at 6 weeks and in platelets at 6 weeks and 3 months compared to those managed with 1st or 2nd generation TKIs. Discussion : The prognostic value of PLR was more apparent in patients treated with 1st or 2nd generation TKIs compared to those treated with osimertinib. Third generation EGFR TKIs may be more efficacious in treating patients with laboratory findings previously shown to predict poor survival. The significant changes in peripheral cell counts suggest variability tumor microenvironment changes dependent on the generation of TKI received.

EGFR T790M mutation detection in NSCLC patients resistant to tyrosine kinase inhibitor therapy.

The finding of mutations that activate epidermal growth factor receptor (EGFR) in people with lung adenocarcinoma resulted in the creation of a new class of biological treatments called tyrosine kinase inhibitors (TKI). These medications have changed how patients with EGFR mutations are clinically managed, nearly doubling their survival rate compared to standard chemotherapy. Though 1st and 2nd generation EGFR TKIs are initially highly effective, typically within 9-14 months all tumors with the mutation progress due to secondary resistance mutations involving alternative molecular pathways. In most cases (up to 60%), this is due to the T790M mutation emerging in the EGFR gene. The study included 85 patients with NSCLC with progression of the disease after treatment with TKI 1st and 2nd generation. The T790M mutation was determined by digital polymerase chain reaction (PCR) on the QIAcuity One 5plex digital PCR system and traditional real-time PCR. Real-time PCR analysis of the presence of the T790M mutation was performed using the Therascreen EGFR Plasma RGQ PCR Kit (Qiagen). Using a digital PCR system in QIAcuity One (Qiagen) nanoplanets, the T790M mutation was analysed by digital PCR. The age of the patients ranged from 37 to 85 years. Of 85 patients with NSCLC with disease progression after TKI treatment, T790M mutations were detected during digital PCR in 30 of 85 patients, which is 35.2% of the sample, and with traditional real-time PCR, positive mutations came out only in 3 out of 85 patients.

Repeated rebiopsy for detection of EGFR T790M mutation in patients with advanced-stage lung adenocarcinoma: Associated factors and treatment outcomes of Osimertinib.

This study was performed to investigate the detection rate of EGFR T790M mutation by repeated rebiopsy, to identify the clinical factors related to repeated rebiopsy, and to assess survival outcomes according to the methods and numbers of repeated rebiopsies in patients with lung adenocarcinoma who received sequential osimertinib after failure of previous 1st or 2nd generation EGFR-tyrosine kinase inhibitors. This retrospective study included patients with advanced-stage lung adenocarcinoma who were confirmed to have EGFR T790M mutation and to have received osimertinib from January 2020 to February 2021 at Samsung Medical Center. The presence of T790M mutation was assessed based on either plasma circulating tumor DNA (ctDNA) or tissue specimens. Results A total of 443 patients underwent rebiopsy, with 186 (42.0%) testing positive for the T790M mutation by the sixth rebiopsy. The final analysis included 143 eligible patients. Progression-free survival was not significantly different in terms of the methods (tissue: 13.3 months, 95% confidence interval [CI]: [9.4, 23.5] vs plasma: 11.1 months, 95% CI: [8.1, 19.4], p = 0.33) and numbers (one: 13.4 months, 95% CI: [9.4, 23.5] vs two or more: 11.0 months, 95% CI: [8.1, 14.8], p = 0.51) of repeated rebiopsies. Longer overall survival (OS) was found in patients in whom T790M was detected by tissue specimens rather than by plasma ctDNA (2-year OS rate: 81.7% for tissue vs 63.9% for plasma, p = 0.0038). Factors related to the lower numbers of rebiopsies included age and bone metastasis. Factor associated with T790M detection in tissue rather than in plasma was pleural metastasis, while advanced tumor stage was related to T790M confirmation in plasma rather than in tissue. Repeated rebiopsy for T790M detection in patients with NSCLC can increase the detection rate of the mutation. Detection of T790M by plasma ctDNA might be related to poor survival outcomes.

Advances in Diagnosis and Targeted Therapy of G719X/L861Q/S768I Mutant Non-small Cell Lung Cancer

Lung cancer accounts for the highest proportion of cancer deaths in the world and poses a great threat to human health. About 30% to 40% of non-small cell lung cancer (NSCLC) is caused by point mutations, exon insertion and exon deletion of the epidermal growth factor receptor (EGFR). In addition to the common exon 19 deletion mutation and exon 21 L858R mutation, exon 18 G719X mutation, exon 21 L861Q mutation and exon 20 S768I mutation are the most important rare mutations. At present, the diagnostic methods for major rare mutations are mainly next-generation sequencing (NGS), digital polymerase chain reaction (dPCR), droplet digital PCR (ddPCR), etc. Regarding the targeted therapy of G719X/L861Q/S768I mutant NSCLC, the first generation EGFR-tyrosine kinase inhibitors (TKIs) have poor efficacy, while the second and third generation EGFR-TKIs have similar efficacy. The novel third generation EGFR-TKIs and combination therapy show a good therapeutic prospect. This article summarized the progress in the diagnosis and targeted therapy of G719X/L861Q/S768I mutant NSCLC, so as to provide reference for subsequent clinical drug use and research. .

Real-world efficacy of low dose osimertinib as second-line treatment in patients with epidermal growth factor receptor-mutated advanced non-small cell lung cancer.

Response rates of epidermal growth factor receptor (EGFR)-mutated advanced non-small cell lung cancer (NSCLC) to lower doses of osimertinib [20 mg once daily (OD) and 40 mg OD] are similar to those of the recommended dose of 80 mg OD, but there is a lack of real-world evidence on the effect of the lower doses of osimertinib on survival outcomes. We conducted this study to assess the efficacy and safety of lower osimertinib doses for patients with EGFR-mutated advanced NSCLC whose disease had progressed on earlier generation EGFR tyrosine kinase inhibitors (TKIs) in a real-world clinical practice. This multicenter, retrospective study included patients with EGFR-mutated advanced NSCLC treated with low doses of osimertinib after failing first- or second-generation EGFR TKIs due to acquired T790M mutation. Data on demographics, staging, treatment history, best overall response rate (ORR) based on RECIST 1.1, and adverse events (AEs) were collected from the patients' case notes. Descriptive data were described in percentages and medians. Progression-free survival (PFS) and overall survival (OS) were calculated using the Kaplan-Meier method. Of the 22 patients studied [males =8 and females =14; Eastern Cooperative Oncology Group (ECOG) 1 or 2 =7 and ECOG 3 or 4 =15], 45.5% were on 40 mg OD, 31.8% were on 80 mg every other day (EOD), and 22.7% on 40 mg EOD. First-line EGFR TKIs used included afatinib, erlotinib, and gefitinib. The ORR with lower doses of second-line osimertinib was 77.3%. Overall, the median PFS was 10.0 months [95% confidence interval (CI): 8.6-11.4] and median OS was 13.0 months (95% CI: 9.4-16.6). In patients with ECOG 1 or 2, the median PFS was 18.0 months (95% CI: 5.8-30.2) and the median OS was not reached at the time of analysis. In patients with poor ECOG performance status of 3 and 4, good survival outcomes were also seen with a median PFS of 7.0 months (95% CI: 4.7-9.3) and median OS of 10.0 months (95% CI: 7.5-12.5). All AEs except one case of paronychia were Grade 1. There were no Grade 3 or 4 AEs. Treatment with low dose osimertinib demonstrated good efficacy and tolerability in EGFR-mutated advanced NSCLC patients who failed first-line treatment with first- or second-generation EGFR TKIs due to T790M mutation.

Targeting Transient Receptor Potential Melastatin-2 (TRPM2) Enhances Therapeutic Efficacy of Third Generation EGFR Inhibitors against EGFR Mutant Lung Cancer.

There is an urgent need to fully understand the biology of third generation EGFR-tyrosine kinase inhibitors (EGFR-TKIs), particularly osimertinib, and to develop mechanism-driven strategies to manage their acquired resistance. Transient receptor potential melastatin-2 (TRPM2) functions as an important regulator of Ca2+ influx, but its role in mediating therapeutic efficacies of EGFR-TKIs and acquired resistance to EGFR-TKIs has been rarely studied. This study has demonstrated a previously undiscovered role of suppression of TRPM2 and subsequent inhibition of Ca2+ influx and induction of ROS and DNA damage in mediating apoptosis induction and the therapeutic efficacy of osimertinib against EGFR mutant NSCLC. The rebound elevation represents a key mechanism accounting for the emergence of acquired resistance to osimertinib and other third generation EGFR-TKIs. Accordingly, targeting TRPM2 is a potentially promising strategy for overcoming and preventing acquired resistance to osimertinib, warranting further study in this direction including the development of cancer therapy-optimized TRPM2 inhibitors.

EGFR-TKI as neoadjuvant treatment in patients with NSCLC with EGFR sensitive mutation: A retrospective real-world analysis.

8081 Background: This study aimed to evaluate the efficacy and outcome of Epidermal growth factor receptor-tyrosine kinase inhibitors (EGFR-TKIs) as preoperative neoadjuvant treatment in patients with NSCLC and EGFR sensitive mutation. Methods: A retrospective analysis was conducted. Patients with resectable stage I-III NSCLCs and received neoadjuvant treatment with any generation of EGFR-TKI before surgical resection were enrolled. The primary endpoint were major pathological response (MPR) and objective response rate (ORR), the second endpoints included diseases down staging, surgical outcomes, disease-free survival (DFS) and overall survival (OS). Results: A total of 58 patients were enrolled. Female accounted for 62.1% and most of them (77.6%) were never-smoker. Forty-five (77.6%) patients received the first generation of EGFR-TKI and 11 received the third. The median duration of EGFR-TKI before surgery was 3.6 months (0.7-19.5m). Nine (15.5%) patients achieved MPR and one patient (1.71%) achieved pathological complete response (pCR). The ORR was 60.3% (35/58) according to RECIST v1.1. Eighteen patients achieved TNM downstaging with T downstaging occurred in 44.8% of patients and N downstaging was about 32.8%. Majority of patients (96.6%) underwent thoracoscopic surgery and the rate of R0 resection was 82.8% (48/58). The DFS and OS of the whole cohort was 25.7months and not reached respectively. Patients with MPR had statistically improved outcomes than those without. What noticeable was that patients with tumor regression grade 3 (13/58) (residual viable tumor cells counts for 10% to 50%) also demonstrated a significant benefit from EGFR-TKI preoperative treatment than those with TRG4 or 5 (residual viable tumor cells&gt;50%) (p = 0.01). We define patients with TRG1 to TRG3 as deep pathological regression (DPR) and the rest as non-DPR, and the DPR cohort showed significantly prolonged DFS than those with non-DPR (median DFS, 60.9 vs 16.7 months; HR, 0.29 (95%CI: 0.11-0.74), p = 0.006), the data of OS was not mature. Subgroup analysis validated DPR was an independent predictive factor for DFS. Conclusions: EGFR-TKI as neoadjuvant therapy had good effect on tumor pathological regression and disease downstaging, DPR patients were more likely to achieve long-term disease-free survival. Patients with NDPR should be closely followed up and appropriate adjuvant therapy was necessary after surgery due to the high risk of reccurence.

OSIRAM-1/TORG1833: Overall survival results of a randomized phase II study of osimertinib plus ramucirumab versus osimertinib alone as initial chemotherapy for EGFR mutation-positive non-squamous non-small cell lung cancer.

8613 Background: Dual inhibition of the EGFR/VEGF pathways has demonstrated superior efficacy with 1st generation EGFR tyrosine kinase inhibitor (TKI) in patients with non-small cell lung cancer (NSCLC) harboring EGFR mutations. This study aims to evaluate the efficacy and safety of combining osimertinib (Osi), a 3rd generation TKI considered the standard of care, with ramucirumab (Ram). We have previously shown the result of progression free survival (PFS) as a primary endpoint, the median PFS was 20.0 months for Osi+Ram and 24.0 months for Osi, hazard ratio of 1.054 (95% CI 0.674-1.648). In further analyses, we aimed to examine the effects of this combination therapy on overall survival (OS). Methods: Previously untreated EGFR mutation-positive advanced non-squamous NSCLC patients with a performance status of 0 or 1 were eligible. Asymptomatic and/or treated brain metastases were included. Eligible patients were randomized at a 1:1 ratio to receive Osi (80mg) every day either without or with Ram (10mg/kg) every 2 weeks until disease progression or unacceptable toxicity, stratified according to gender and the type of EGFR mutation (exon 19 deletion, L858R). The primary endpoint was PFS assessed by the independent blinded radiologic reviewer. Secondary endpoints included PFS assessed locally, objective response rate (ORR), disease control rate (DCR), duration of response (DOR), OS and safety. Results: Between November 2018 and April 2020, 122 patients (Osi+Ram: 59, Osi: 63) were enrolled. The patients' characteristics were well balanced. 59% were females, and 61% had an exon 19 deletion. Median age was 70 years old (range, 29-86). With a median follow up of 36.0 months, the median OS was 43.4 months (95% CI 36.5-N.R.) for Osi+Ram and N.R. (95% CI 41.3-N.R.) for Osi, resulting in a hazard ratio of 1.159 (95% CI 0.645-2.083, p = 0.62). Median treatment duration for Ram was 140 (14-1239) days. Ram was discontinued in 45 patients (76%) by the treatment related adverse effects. Common reasons for Ram discontinuation were platelet count decreased (n=14), proteinuria (n=12), neutrophil count decreased (n=11), pneumonitis (n=3), bleeding (n=3) and infection (n=3). Pneumonitis was observed in 16% in Osi, 9% in Osi+Ram, with grade 3 observed in 2% of both arms. Conclusions: Both treatment arms demonstrated sustained OS over 43 months. However, this study did not show an advantage of biweekly Ram administration with Osi in terms of PFS and OS. Notably, there was surpassed increase of early discontinuation of Ram due to higher adverse events. Clinical trial information: 2080224085 .

Abstract CT055: Efficacy of YK-029A, a novel EGFR TKI, in advanced NSCLC patients with acquired T790M mutation

Abstract In the multicenter, dose-escalation and dose-expansion phase 1 clinical trial (NCT05767866), we evaluated safety and tolerability of YK-029A in various EGFR mutated non-small-cell lung cancer (NSCLC). We have reported efficacy of YK-029A in untreated NSCLC with EGFR ex20ins mutation[1]. This time we report efficacy of YK-029A in patients with acquired EGFR T790M mutation after failure of first or second generation EGFR tyrosine kinase inhibitors (TKIs). Method: This dose-escalation and dose-expansion phase 1 trial recruited previously treated NSCLC patients with EGFR T790M mutation or patients with EGFR ex20ins or EGFR 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 EGFR rare mutations were enrolled. The primary objective was safety. Dose-limiting toxicity (DLT) and maximum tolerated dose (MTD) were explored. Efficacy of YK-029A in EGFR T790M mutated NSCLC was assessed by the investigators. Results: A total of 114 patients were recruited into the study. Safety profile of the first 108 patients was reported previously[1]. By the cut-off date on Sep 12, 2023, 38 patients harbored EGFR T790M mutation were included in efficacy analysis. All these patients were previously treated with first or second generation EGFR-TKIs. The objective response rate (ORR; RECIST 1.1) was 65.8% (95%CI: 48.6%-80.4%) and disease control rate (DCR) was 84.2% (95%CI: 68.7%-94.0%). With a median follow-up time of 8.2 months,the median progression free survival (PFS) was 11.0 months (95%CI: 7.75-NR). The median overall survival (OS) was not reached. Among the 8 patients with measurable brain metastases, intracranial ORR was 75% (95%CI: 35.6%-95.6%) . Conclusions: YK-029A has promising activity in previously treated NSCLC patients harboring EGFR T790M mutation. Reference[1] DUAN J, WU L, YANG K, et al. Safety, Tolerability, Pharmacokinetics, and Preliminary Efficacy of YK-029A in Treatment-Naive Patients With Advanced NSCLC Harboring EGFR Exon 20 Insertion Mutations: A Phase 1 Trial [J]. J Thorac Oncol, 2023. Citation Format: Rui Wan, Yi Fung Chau, Jun Zhao, Zhe Liu, Mingfang Zhao, Yanqiu Zhao, Xiumei Dai, Yueyin Pan, Zhihong Zhang, Yu Yao, Kunyu Yang, Lin Wu, Yanyan Xie, Bi Chen, Yixuan Yang, Yongqi Guo, Jie Wang, Jianchun Duan. Efficacy of YK-029A, a novel EGFR TKI, in advanced NSCLC patients with acquired T790M mutation [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 2 (Late-Breaking, Clinical Trial, and Invited Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(7_Suppl):Abstract nr CT055.

Abstract 1961: Discovery of a highly potent and brain penetrant fourth generation EGFR tyrosine kinase inhibitor

Abstract Third generation EGFR tyrosine kinase inhibitors (TKIs) such as Osimertinib have emerged as first-line standard of care therapy to treat non-small cell lung cancer (NSCLC) patients with activating EGFR mutations (del19, L858R or T790M). However, within 12 to 18 months following treatment, 15-20% of the patients develop C797S mutation, which drives resistance to these drugs; with the progression of disease brain metastasis is observed in 40-70% of the EGFRm+ NSCLC patients. Here, we report a highly potent and brain penetrant fourth generation EGFR-TKI ACE-34237307, designed to overcome C797S mutation (del19/C797S and L858R/C797S), and common single point mutations (del19 and L858R). ACE-34237307 is also designed to potently inhibit the more prevalent non-canonical EGFR mutations such as G719S and L861Q. ACE-34237307 showed robust anti-proliferative activity against EGFR double mutations in Ba/F3 (EGFR-del19/C797S and EGFR-L858R/C797S) cell lines with IC50 values of 0.1 and 0.23 nM, respectively. In phospho-EGFR assay, ACE-34237307 demonstrates over 79-fold selectivity against A431 (EGFR-WT) cell line when compared to PC-9 (EGFR-del 19) cell line. ACE-34237307 is highly brain penetrant with B/P ratio of 2.3 in rat and 1.2 in mouse. It has an excellent pharmacokinetic profile in rat, mouse and dog with good bioavailability, a flat PK curve and reduced Cmax, which will translate to a better safety profile. The in vivo anti-tumor efficacy was evaluated in Osimertinib resistant double mutant Ba/F3-EGFR-del19/C797S and L858R/C797S as well as del19 and L858R single mutant xenograft models. It has been shown that ACE-34237307 at doses of ≥ 0.6 mg/kg induces complete tumor regression or eradication in all tumor models tested. In brain tumor models with Ba/F3 (EGFR-del19/C797S) and PC-9 (EGFR-del19), ACE-34237307 showed complete inhibition or eradication of brain tumors and drastically extended animal survival at ≥ 0.6 mg/kg. In summary, ACE-34237307 is a potent fourth generation EGFR-TKI with high WT selectivity, excellent brain penetration, highly favorable DMPK profile, outstanding in vivo efficacy in subcutaneous and brain tumor models and low projected human dose amenable to QD dosing. Citation Format: sanjeev kumar, junmei wang, wenqian li, weitao pan, zhiming wen, Kuo-Long yu, Genshi Zhao, tinggui yin. Discovery of a highly potent and brain penetrant fourth generation EGFR tyrosine kinase inhibitor [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 1961.

Abstract 4756: Targeting DNA topoisomerase II to manage acquired resistance to third generation EGFR tyrosine kinase inhibitors in the treatment of EGFR mutant NSCLC

Abstract Development of effective strategies to manage the inevitable acquired resistance to osimertinib, a 3rd generation EGFR inhibitor with proven clinical efficacy in prolonging survival of patients with EGFR mutant (EGFRm) non-small cell lung cancer (NSCLC), is an urgent and critical area of unmet need in the clinic. Effort toward this direction led us to find that the DNA topoisomerase II (Topo II) inhibitors, doxorubicin and etoposide (VP-16), but not other chemotherapeutic agents, synergistically decreased the survival of osimertinib-resistant cell lines when combined with osimertinib. The combination of osimertinib with either doxorubcin or VP-16 effectively induced DNA damage and apoptosis in osimertinib-resistant cells, suppressed the growth of osimertinib-resistant tumors, and delayed the emergence of acquired resistance to osimertinib. Mechanistic studies found that osimertinib as well other EGFR-TKIs effectively decreased Topo IIα levels in EGFRm NSCLC cells by facilitating its proteasomal degradation and induced DNA damage; these effects were lost in cell lines with osimertinib acquired resistance that possessed elevated basal levels of Topo IIα. In the majority of EGFRm NSCLC tissues relapsed from EGFR-TKI treatment, Topo IIα levels were substantially increased. Enforced expression of ectopic TOP2A genes in sensitive EGFRm NSCLC cells conferred resistance to osimertinib in inducing DNA damage and apoptosis, whereas knockdown of TOP2A in osimertinib-resistant cell lines restored their responses to undergo osimertinib-induced DNA damage and apoptosis. Together, these results reveal a previously undiscovered essential role of Topo IIα modulation in regulating the responses of EGFRm NSCLC cells to osimertinib, providing scientific rationale for targeting Topo II to manage acquired resistance to osimertinib and possibly other third generation EGFR-TKIs, thus warranting clinical validation of this strategy. (This study was supported by NIH/NCI R01 CA223220 and UG1 CA233259 and Emory Winship Cancer Institute lung cancer research pilot funds). Citation Format: Zhen Chen, Karin A. Vallega, Dongsheng Wang, Zihan Quan, Songqing Fan, Qiming Wang, Ticiana A. Leal, Suresh S. Ramalingam, Shi-Yong Sun. Targeting DNA topoisomerase II to manage acquired resistance to third generation EGFR tyrosine kinase inhibitors in the treatment of EGFR mutant NSCLC [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 4756.

Abstract 7203: Anti-HDGF antibody attenuates the rise of resistance to EGFR tyrosine kinase inhibitor in NSCLC patient-derived xenograft tumors

Abstract Mutant epidermal growth factor receptor (EGFR), a major oncogenic driver in non-small cell lung cancer (NSCLC), is found in the tumors of 15% (western countries) to 50% (Asian countries) of patients. EGFR-targeted therapy using tyrosine kinase inhibitors (TKIs) is a standard of care for those patients who developed metastatic or recurrent diseases. However, despite having an 80% initial response rate, most patients had partial tumor regression and their disease would progress when acquired resistance emerges. Thus, developing more effective treatment is an unmet need. The clinical response of these patients can be recapitulated in mouse models of patient-derived xenograft (PDX) tumor bearing sensitizing EGFR mutations. In this study, treating established PDX tumors with osimertinib, a third generation EGFR TKI, induced partial tumor regression (50% to 70% size reduction from baseline) followed by progression with a median progression-free survival (PFS) of 26 to 28 days. Interestingly, co-administering an antibody against hepatoma-derived growth factor (HDGF) with osimertinib resulted in enhanced tumor regression (98% to 100% size reduction from baseline) which translated into significantly extended animal survival with a median PFS of 103 or 135 days. Immunohistochemical and western blot examination of tumors collected at different treatment timepoints indicated that AKT/mTOR and MAPK pathways were reactivated after initial suppression in TKI monotherapy arm despite persistent EGFR inhibition. Since AKT/mTOR and MAPK pathways are key survival and proliferative signaling pathways, their reactivation can promote TKI tolerance of tumor cells and the emergence of TKI resistance. However, blocking HDGF attenuated the reactivation of these pathways which could partially explain the enhanced efficacy of osimertinib plus anti-HDGF antibody combination treatment seen in this study. Our results suggest tumor-derived HDGF could play a crucial role in the rise of acquired resistance to osimertinib. Identifying the exact cells and molecular pathways utilized by HDGF to promote tumor cell tolerance to TKI will help us understand how TKI sensitive tumor cells survive EGFR blockade and emerge as resistant cells. Citation Format: Cindy Q. Zhou, Ariel Li, Kaoru Ri, Ahmed Sultan, Hening Ren. Anti-HDGF antibody attenuates the rise of resistance to EGFR tyrosine kinase inhibitor in NSCLC patient-derived xenograft tumors [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 7203.

Abstract 946: Landscape of HRD aberration in EGFR mutated lung cancer and the role of PARP-inhibitor in EGFR mutated lung cancer with HRD aberration

Abstract Introduction: Olaparib, an oral poly polymerase (PARP) inhibitor has received approval for treating malignancies displaying homologous recombination deficiency (HRD). Current data is insufficient in establishing the role of PARP inhibitors in non-small cell lung cancer (NSCLC) in the setting of third generation EGFR tyrosine kinase inhibitor (TKI) use. Preclinical investigation suggests heightened PARP inhibitor sensitivity of TKI-resistant EGFR mutant NSCLC cells compared to TKI-sensitive cells. Methods: We utilized The Cancer Genome Atlas (TCGA) to investigate the prevalence of HRD gene mutations in patients with NSCLC harboring EGFR mutations. We also present a case demonstrating a favorable response to the dual therapy of olaparib and osimertinib in NSCLC harboring EGFR, RAD50, and ARID1A mutations that progressed on osimertinib. Results: There were 2298 patients in the NSCLC cohort (MSKCC database). Among 687 patients with EGFR mutations, 24 patients (3.5%) exhibited ARID1A mutations, 8 patients (1.2%) had BRCA1 mutations, 11 patients (1.6%) had BRCA2 mutations, and 5 (0.7%) had RAD50 mutations. A 71-year-old female presented with stage IV adenocarcinoma of the lung. She had recurrent malignant pericardial effusion requiring pericardiocentesis for previous cardiac tamponade. Computed tomography (CT) of the chest revealed a 3cm irregular left hilar mass with bilateral mediastinal and hilar lymph nodes. Tissue next generation sequencing (NGS) at baseline identified EGFR exon19 deletion along with RAD50 R726H which is a HRD pathway gene. Circulating tumor DNA (ct-DNA) NGS (Guardant360) showed EGFR E746_A750del 4.8%. The patient achieved partial response to osimertinib for 28 months. Follow-up CT showed disease progression. Olaparib 200mg twice daily was added to osimertinib based on repeat ct-DNA NGS indicating a new ARID1A alteration (splice site SNV) along with the known BRCA1 mutation. Follow up scans currently have consistently demonstrated ongoing partial response for 19 months. Combining olaparib with osimertinib can be effective in an osimertinib-resistant NSCLC patient with EGFR mutation and HRD aberration. The favorable response could be attributed not only to pre-existing RAD50 mutation but also to acquired mutations in ARID1A HRD genes. Conclusion: HRD aberrations are uncommon in EGFR mutated lung cancer patients. Further investigation on the role of PARP inhibitor in EGFR mutated lung cancer is warranted. Citation Format: Jinah Kim, Horyun Choi, Liam Il-Young Chung, Young Kwang Chae. Landscape of HRD aberration in EGFR mutated lung cancer and the role of PARP-inhibitor in EGFR mutated lung cancer with HRD aberration [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 946.

Investigating the Efficacy of EGFR-TKIs and Anti-VEGFR Combination in Advanced Non-Small Cell Lung Cancer: A Meta-Analysis.

The epidermal growth factor receptor tyrosine kinase inhibitors (EGFR-TKIs) in combination with anti-vascular endothelial growth factor receptor (VEGFR) agents have shown improved survival outcomes in recent studies. However, its efficacy related to survival outcomes as a first- or second-line agent and based on generations remains to be explored. This study estimated the survival outcomes of EGFR-TKIs plus anti-VEGFR in combination in defined populations of advanced non-small cell lung cancer (NSCLC) patients overall, as a first- or second line of treatment, with different generations of EGFR-TKIs and EGFR-TKIs plus bevacizumab combination as a subgroup. A literature search was conducted using PubMed, SCOPUS, Cochrane Library, and ClinicalTrials.gov databases through June 2023 to identify primary research reporting the survival outcomes of EGFR-TKIs in combination with anti-VEGFR agents in patients with advanced NSCLC. Studies that were single-arm, published in non-English languages, and had missing data on survival outcomes were excluded. A meta-analysis was conducted to generate pooled hazard ratios (HRs) with 95% confidence intervals (CI) for overall survival (OS) and progression-free survival (PFS). Methodological quality and risk of bias in studies were assessed using the Cochrane Handbook for Systematic Reviews of Interventions risk of bias tool. A total of 20 randomized controlled trials were included in the qualitative synthesis, and 11 (2182 participants) were included in the meta-analysis. Patients' median age ranged from 58 to 68 years; 36% to 70% of patients were female; most of them had IIIa/b to IV stage cancer. In meta-analyses, the EGFR-TKIs plus anti-VEGFR combination resulted in improved PFS (HR, 0.73; 95% CI: 0.61, 0.86; p < 0.00001) in patients with advanced NSCLC but had no impact on OS (HR, 0.93; 95% CI: 0.79, 1.10; p = 0.41). The first line of treatment and first-generation EGFR-TKIs with the combination also improved the PFS (HR, 0.64; 95% CI: 0.57, 0.71; p < 0.00001; HR, 0.63; 95% CI: 0.56, 0.71; p < 0.00001) respectively, however, had no impact on OS. Our meta-analysis indicated EGFR-TKIs with anti-VEGFR in combination not only improved overall PFS but also showed similar results to a first line and first-generation agent compared to EGFR-TKI alone.

Analysis of the effect of baseline detection and early clearance of ct-DNA, on survival outcomes among patients with advanced EGFR-mutant non-small cell lung cancer.

To determine if circulating tumor DNA (ct-DNA) dynamics of epidermal growth factor receptor (EGFR) mutation in plasma can identify asubset of patients with EGFR-mutant (EGFR- m) non-small cell lung cancer (NSCLC) with inferior survival outcomes, we analyzed and compared survival outcomes among patients with and without baseline presence and early clearance of EGFR ct-DNA in plasma. For 66patients newly dia-gnosed with EGFR- m NSCLC, plasma samples were collected at baseline and 1st response assessment at 12-24weeks for extraction of ct-DNA. Estimation of ct-DNA (EGFR exons 18, 19, 20and 21) was done using droplet digital polymerase chain reaction (dd-PCR) on the QX200ddPCR system (BioRad, USA). Patients with detectable EGFR ct-DNA at baseline (sample 1), with either undetectable or persistent detectable ct-DNA in sample 2were classified as clearers and non-clearers, respectively. Fifty-three patients received 1st/ 2nd generation EGFR tyrosine kinase inhibitors (TKIs) and 13received either 3rd generation TKI (osimertinib) or chemotherapy plus gefitinib. The baseline ct-DNA-positive group had more patients with extra thoracic disease (60.4vs. 48.5%). For the entire cohort, there was no difference in median progression-free survival (PFS) among baseline ct-DNA-negative (13.57months) vs. ct-DNA-positive patients (12.32months) (HR 0.74). There was asignificant improvement of PFS among early ct-DNA clearers vs. non-clearers (12.32vs. 9.92months; HR 0.57). For those treated with 1st/ 2nd generation EGFR TKIs, this improvement in median PFS among early ct-DNA clearers vs. non-clearers was more apparent (11.76vs. 6.8months; HR 0.34). Baseline detection of the presence of ct-DNA of EGFR mutation in plasma was not predictive of first-line PFS, but is associated with extra thoracic disease. Patients with EGFR mutation and persistence of ct-DNA at first follow-up have worse PFS and overall survival (OS) in comparison to those clearing the same in plasma, especially among those treated with 1st/ 2nd generation EGFR TKIs.

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

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

Machine Learning-Based Virtual Screening and Identification of the Fourth-Generation EGFR Inhibitors.

Epidermal growth factor receptor (EGFR) plays a pivotal regulatory role in treating patients with advanced nonsmall cell lung cancer (NSCLC). Following the emergence of the EGFR tertiary CIS C797S mutation, all types of inhibitors lose their inhibitory activity, necessitating the urgent development of new inhibitors. Computer systems employ machine learning methods to process substantial volumes of data and construct models that enable more accurate predictions of the outcomes of new inputs. The purpose of this article is to uncover innovative fourth-generation epidermal growth factor receptor tyrosine kinase inhibitors (EGFR-TKIs) with the aid of machine learning techniques. The paper's data set was high-dimensional and sparse, encompassing both structured and unstructured descriptors. To address this considerable challenge, we introduced a fusion framework to select critical molecule descriptors by integrating the full quadratic effect model and the Lasso model. Based on structural descriptors obtained from the full quadratic effect model, we conceived and synthesized a variety of small-molecule inhibitors. These inhibitors demonstrated potent inhibitory effects on the two mutated kinases L858R/T790M/C797S and Del19/T790M/C797S. Moreover, we applied our model to virtual screening, successfully identifying four hit compounds. We have evaluated these hit ADME characteristics and look forward to conducting activity evaluations on them in the future to discover a new generation of EGFR-TKI.

Research On Befortinib: Characteristics, Role, And Development of Fourth-Generation EGFR-Tkis

Lung cancer is one of the most common cancers in terms of morbidity and mortality. Among them, non-small cell lung cancer (NSCLC) accounts for 90% of lung cancer patients. Epidermal Growth Factor Receptor (EGFR) mutations are also the most common type of driver gene mutation in advanced NSCLC. In Chinese NSCLC patients, the proportion of EGFR mutations was 28.2%, and this proportion increased to 50.2% in lung adenocarcinoma. All three generations of Epidermal Growth Factor Receptor Tyrosine Kinase Inhibitors (EGFR-TKI) are effective therapeutics for lung cancer patients carrying EGFR-sensitive mutations or T790M mutations, each of which has its own advantages and characteristics, as well as its own limitations and adverse reactions. Befortinib, which is new to the market in 2023, has better Median progression-free survival (mPFS). However, three generations of EGFR-TKI cannot completely overcome the resistance mechanism of lung cancer. In addition to the T790M mutation, there are other mutations or mechanisms that cause lung cancer to become resistant to third-generation EGFR-TKI, such as C797S mutation, MET amplification, HER2 amplification, etc. At present, the fourth-generation of EGFR-TKI is still under continuous research and development.

Abstract B076: Discovery of BBT-176 as fourth generation EGFR tyrosine kinase inhibitor

Abstract Epidermal growth factor receptor (EGFR) tyrosine kinase inhibitors (TKIs) improve overall survival rate in patients with EGFR mutated non-small cell lung cancers (NSCLC). However, upon treatment with third-generation EGFR TKIs (Osmertinib) develops C797S resistance[KS1] [u2] in the 20 – 30% of the patients. To date, there is no approved drug for third-generation resistance NSCLC patients. There is an unmet medical need to develop fourth generation EGFR TKIs[KS3] targeting C797S mutation. Extensive structure–activity relationship (SAR) studies led to the discovery of BBT-176 as a reversible fourth generation EGFR TKI. BBT-176 shows promising results with highly potent and anti-cancer efficacy in Osmertinib-resistant in vitro and in vivo cell lines. In mouse models, BBT-176 exhibited potent inhibition of tumor growth, leading to tumor regression in certain cases. Furthermore, promising results were observed in the clinical trial, where two patients with EGFR Del[KS4] 19/T790M/C797S mutations in their blood demonstrated tumor shrinkage and improvements in radiological assessments. BBT-176, a fourth-generation EGFR inhibitor, demonstrates significant preclinical activity against non-small cell lung cancer (NSCLC) that is resistant to current EGFR tyrosine kinase inhibitors (TKIs). This promising compound has shown early signs of clinical efficacy and safety in initial trials. Citation Format: Krishna Babu Duggirala, Kwangho Lee. Discovery of BBT-176 as fourth generation EGFR tyrosine kinase inhibitor [abstract]. In: Proceedings of the AACR-NCI-EORTC Virtual International Conference on Molecular Targets and Cancer Therapeutics; 2023 Oct 11-15; Boston, MA. Philadelphia (PA): AACR; Mol Cancer Ther 2023;22(12 Suppl):Abstract nr B076.