Generation Epidermal Growth Factor Receptor Tyrosine Kinase Inhibitors Research Articles

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.

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.

A Phase II Study of Osimertinib in Patients with Advanced-Stage Non-Small Cell Lung Cancer following Prior Epidermal Growth Factor Receptor Tyrosine Kinase Inhibitor (EGFR TKI) Therapy with EGFR and T790M Mutations Detected in Plasma Circulating Tumour DNA (PLASMA Study).

Epidermal growth factor receptor (EGFR) T790M mutations drive resistance in 50% of patients with advanced non-small cell lung cancer (NSCLC) who progress on first/second generation (1G/2G) EGFR tyrosine kinase inhibitors (TKIs) and are sensitive to Osimertinib. Tissue sampling is the gold-standard modality of T790M testing, but it is invasive. We evaluated the efficacy of Osimertinib in patients with EGFR mutant NSCLC and T790M in circulating tumour DNA (ctDNA). PLASMA is a prospective, open-label, multicentre single-arm Phase II study. Patients with advanced NSCLC harbouring sensitizing EGFR and T790M mutations in plasma at progression from ≥one 1G/2G TKI were treated with 80 mg of Osimertinib daily until progression. The primary endpoint was the objective response rate (ORR); the secondary endpoints included progression-free survival (PFS), overall survival (OS), disease control rate (DCR) and toxicities. Plasma next-generation sequencing was performed to determine Osimertinib resistance mechanisms and assess serial ctDNA. A total of 110 patients from eight centres in five countries were enrolled from 2017 to 2019. The median follow-up duration was 2.64 (IQR 2.44-3.12) years. The ORR was 50.9% (95% CI 41.2-60.6) and the DCR was 84.5% (95% CI 76.4-90.7). Median PFS was 7.4 (95% CI 6.0-9.3) months; median OS was 1.63 (95% CI 1.35-2.16) years. Of all of the patients, 76% had treatment-related adverse events (TRAEs), most commonly paronychia (22.7%); 11% experienced ≥ Grade 3 TRAEs. The ctDNA baseline load and dynamics were prognostic. Osimertinib is active in NSCLC harbouring sensitizing EGFR and T790M mutations in ctDNA testing post 1G/2G TKIs.

Knowledge-based mechanistic modeling accurately predicts disease progression with gefitinib in EGFR-mutant lung adenocarcinoma

Lung adenocarcinoma (LUAD) is associated with a low survival rate at advanced stages. Although the development of targeted therapies has improved outcomes in LUAD patients with identified and specific genetic alterations, such as activating mutations on the epidermal growth factor receptor gene (EGFR), the emergence of tumor resistance eventually occurs in all patients and this is driving the development of new therapies. In this paper, we present the In Silico EGFR-mutant LUAD (ISELA) model that links LUAD patients’ individual characteristics, including tumor genetic heterogeneity, to tumor size evolution and tumor progression over time under first generation EGFR tyrosine kinase inhibitor gefitinib. This translational mechanistic model gathers extensive knowledge on LUAD and was calibrated on multiple scales, including in vitro, human tumor xenograft mouse and human, reproducing more than 90% of the experimental data identified. Moreover, with 98.5% coverage and 99.4% negative logrank tests, the model accurately reproduced the time to progression from the Lux-Lung 7 clinical trial, which was unused in calibration, thus supporting the model high predictive value. This knowledge-based mechanistic model could be a valuable tool in the development of new therapies targeting EGFR-mutant LUAD as a foundation for the generation of synthetic control arms.

Enhanced detection and characterization of targetable EGFR and ERBB2 exon20 insertion mutations in urothelial carcinoma.

e16500 Background: EGFR and ERBB2 exon 20 insertion (exon20ins) driver mutations are well described in non-small cell lung cancer due to their resistance to early generation EGFR tyrosine kinase inhibitors. This has led to the development and ultimate approval of exon20ins specific inhibitors, such as mobocertinib. Previous studies have reported EGFR and ERBB2 exon20ins mutations in 0.15%-1.91% of urothelial carcinoma (UC) patients, but this is likely an underrepresentation as indel variants are often under detected by commonly used NGS-variant analysis tools. Additionally, little is known about the biological consequences of EGFR and ERBB2 exon20ins mutations in UC. In this study, we aimed to: 1) characterize the prevalence of EGFR and ERBB2 exon20ins mutations in UC; 2) assess how EGFR and ERBB2 exon20ins mutations impact malignant transformation; and 3) evaluate the sensitivity of UC cell lines with the exon20ins to mobocertinib. Methods: UC patient datasets were realigned using the indel caller, ABRA2, then EGFR and ERBB2 exon20ins frequencies were calculated. Next, parental KT1970 urothelial cells expressing either EGFR WT, ERBB2 WT, or exon20ins mutation constructs (EGFRinsH [insH] or ERBB2insYVMA [YVMA]) were generated and in vitro transformation assays were performed. Anchorage-independent growth was assessed with soft agar assay. Engineered urothelial organoids with various exon20ins variants were created to assess for their ability to differentiate. Finally, sensitivity to erlotinib and mobocertinib was determined. Results: ABRA2 identified a prevalence of ERBB2 and EGFR Exon20ins mutations in 2.5% (7/275) of urothelial tumors in the IMVigor210 patient cohort. ERBB2 insYVMA expressing organoids had the highest basal marker (KRT5) expression in proliferation media which decreased in differentiation media. In the soft agar assay, YVMA cells had a 9.26 fold increase in colony formation (CF) compared to the ERBB2 WT counterpart and insH had a 6.02 fold increase in CF over the EGFR WT counterpart. The IC50 for mobocertinib (M) was significantly lower than erlotinib (E) in the exon20ins cell lines (insH M: 0.123 uM, E:10.69 uM / YVMA M: 0.57 uM, E: 13.54 uM). The difference in IC50 values for mobocertinib vs erlotinib in the WT cells was less pronounced. Conclusions: The prevalence of EFGR and ERBB2 exon20 insertion mutations is likely unrepresented in urothelial carcinoma by current variant calling pipelines. The ERBB2 YVMA mutation showed a more aggressive phenotype and possible basal pattern in vitro which may have implications in terms of prognosis and treatment considerations. Both EGFR and ERBB2 exon20ins urothelial cells were more sensitive to mobocertinib. This study provides evidence that exon20ins specific inhibitors could offer additional targeted therapy options for patients with urothelial cancer who have EGFRinsH and ERBB2insYVMA mutations.

Osimertinib then chemotherapy in EGFR-mutated lung cancer with osimertinib third-line rechallenge (OCELOT).

TPS9160 Background: The results of the FLAURA study established osimertinib as the new first-line standard of care for patients with the two ‘common’ types of epidermal growth factor receptor mutation-positive (EGFR+) advanced non-small-cell lung cancer (aNSCLC). Second-line (2L) treatment is typically platinum pemetrexed chemotherapy and the standard third-line (3L) treatment is docetaxel throughout much of the globe, which has a modest response rate of 7 – 15%. Previously, when first generation (1G) EGFR tyrosine kinase inhibitor (TKIs) were standard of care in the first-line setting, a number of prospective and retrospective studies examined 3L rechallenge with the same 1G EGFR TKI following 2L chemotherapy, with varying levels of success. Osimertinib is a well-tolerated EGFR TKI which is active against the T790M resistance mutation, which would have limited the efficacy of rechallenge with 1G EGFR TKIs. Methods: This is a multicentered international phase II investigator-initiated study of osimertinib in the 3L rechallenge of patients with EGFR+ aNSCLC, following 1L treatment with osimertinib and 2L therapy with platinum pemetrexed chemotherapy. A maximum of 255 patients will be enrolled. Patients with ‘common’ EGFR exon 19 deletions or L858R mutations will enroll at the start of 2L chemotherapy or 3L osimertinib rechallenge. The primary objective is 3L objective response rate (ORR) in the first 100 evaluable patients, according to RECIST 1.1. Secondary objectives include disease control rate (DCR), progression free survival (PFS), time to treatment failure, overall survival and toxicity for 3L osimertinib rechallenge. Exploratory objectives include assessment of osimertinib resistance based on serial ctDNA samples collected from all participants. The OCELOT study, NCT04335292, is actively enrolling participants. Clinical trial information: NCT04335292 .

Real-world clinical outcomes in a U.S. Asian population with stage IV NSCLC treated with osimertinib (Osi) stratified by EGFR subtype.

e21128 Background: EGFR mutations are observed in 40-50% of Asian populations with NSCLC compared to 10-15% in Caucasian populations, with EGFR exon 19 deletion (ex19del) and exon 21 L858R as the most common activating mutations. The FLAURA trial demonstrated PFS and OS benefit of osi, a 3rd generation tyrosine kinase inhibitor (TKI), compared to earlier generation TKIs with a median PFS (mPFS) of 19 months (mos) and overall survival (OS) of 38.6 mos. Subgroup analysis, however, suggested this survival benefit was not seen in Asian patients (pts) or in pts with the L858R mutation. Further analysis of the 322 Asian pts enrolled at Asian sites demonstrated a mPFS of 16.5 mos (HR 0.54, p &lt; 0.0001) with osi compared to 11.0 mos with SOC EGFR TKI, but no difference on two-year OS (2y OS) (HR 0.65, 95% CI 0.42-1.02). We evaluated the 2y OS in Asian pts treated in the U.S. with stage IV NSCLC with first-line (1L) osi. We further explored the 2y OS of Asian pts who received an earlier generation EGFR TKI prior to osi. Methods: We conducted a single institution IRB-approved retrospective study of Asian pts treated at NYU Perlmutter Cancer Center with stage IV NSCLC with EGFR ex19del or L858R mutations treated with osi from 1/1/2010 – 2/1/2021. 2y OS was compared based on EGFR mutations and receipt of 1L osi vs an earlier generation EGFR TKI prior to osi (TKI-pretreated). Log-rank test was used to calculate the P values of Kaplan-Meier curves subgroups. Cox proportional-hazards model was used to investigate the association between the survival time of pts and multiple predictor variables including age, sex, EGFR subtypes (L858R or ex19del) and smoking status. Results: Of 117 total cases: 85 (73%) were female, 32 (36%) were male. 57 (49%) had ex19del and 60 (51%) had L858R. 94 (80%) were nonsmokers. Age range at diagnosis with stage IV disease was 31-96 years. The analysis revealed no significant difference in 2y OS observed between the 1L osi vs. TKI-pretreated groups (HR 1.90, 95%CI 0.93-3.89). However, the subgroup analysis showed that the 2y OS was inferior in the 1L osi group compared to the TKI-pretreated group in pts with ex19del (HR 2.99, 95%CI 1.12 -7.96), but not in those with L858R (HR 1.29, 95%CI 0.43-3.86). No significant effect on 2y OS was observed from age (p = 0.19), sex (p = 0.50), EGFR subtype (p = 0.19) or smoking status (p = 0.67). Conclusions: In accordance with the FLAURA data, our real-world analysis revealed that Asian pts treated with 1L osi was comparable to pts treated with 1st- or 2nd- generation TKIs. Furthermore, our data showed that the use of 1L osi had a lower 2y OS in Asian pts with ex19del compared to those pre-treated with TKIs, but this was not the case with L858R. Although small numbers, the results suggest that ex19del and L858R should be considered differently when considering 1L treatment options and further investigation into alternative options, such as combination therapies, warrants exploration.

Abstract 933: Real world treatment patterns and outcomes in patients with advanced non-small cell lung cancer (aNSCLC) post-EGFR tyrosine kinase inhibitor (TKI) therapy

Abstract Background:Third generation EGFR TKIs have emerged as a first line treatment of choice for aNSCLC patients with qualifying EGFR mutations due to high and durable response rates; however most patients will progress on therapy and may receive further treatment. Second line (2L) options include other EGFR TKIs, chemotherapy (C) and chemoimmunotherapy (C-IO). An optimal treatment strategy and utility of biomarkers in this 2L setting remain uncharacterized. In this study, we aim to describe the real-world treatment patterns and outcomes of patients with aNSCLC after treatment with first line (1L) EGFR TKIs to elucidate the potential for biomarker-guided approaches. Methods:We selected patients with non-squamous aNSCLC treated with 1L EGFR TKIs on or after April 1, 2018 (based on 1L approval of osimertinib) within the US-based de-identified Flatiron Health-Foundation Medicine (FMI) real world clinico-genomic database. Real world overall survival (rwOS) and progression free survival (rwPFS) curves and estimates of median survival time were generated using the Kaplan-Meier method. PD-L1 and tumor mutational burden (TMB) were summarized overall and by 2L treatment regimen. Results:Among 428 patients who received 1L EGFR TKI treatment, 386 (90%) received osimertinib, 30 (7%) received afatinib and 11 (3%) received erlotinib. For patients with known 2L treatment information (n=139, 32%) most received EGFR TKI alone (n=43, 31%), followed by C-IO (n=38, 27%), and C alone (n=14, 10%). Median rwOS following 2L treatment with EGFR TKI, C-IO, and C was 21.0 (95% CI 17.4-28.7) months, 9.9 (95% CI 7.7-19.8) months, and 17.4 (95% CI 4.3-NA) months respectively. Median rwPFS for the EGFR-TKI, C-IO, and C cohorts was 5.1 (95% CI 3.4-12.5) months, 5.5 (95% CI 3.3-7.0) months, and 3.5 (95% CI 1.9-NA) months. 416 (97%) of 428 patients harbored an EGFR mutation detected by FoundationOne®CDx, including 361 (84%) patients with at least one EGFR mutation in NCCN Guidelines. Among patients with available PD-L1 status (n=254, 59%), PD-L1 positivity (≥1% tumor proportion score) was more common among patients who received 2L C-IO (88%) compared to patients overall (59%). 30 (7%) of 428 patients had high TMB (≥10 mut/Mb); prevalence of high TMB was similar regardless of 2L therapy choice. Conclusions:This real-world data analysis confirmed that among patients with aNSCLC treated with EGFR TKIs, the vast majority received 1L osimertinib. Among 2L treatment options, additional EGFR TKI use was the most common and patients in this cohort had robust outcomes, with a median rwOS of 21 mos. Further analyses will describe the clinical characteristics of patients receiving different 2L treatment strategies and evaluate the association of PD-L1 status and select EGFR mutations with outcomes across therapeutic classes. Citation Format: Ericka Ebot, Jie He, David Fabrizio, Ivy Altomare, Neha Jain, Davey Daniel, Thomas Stricker, Edward Arrowsmith. Real world treatment patterns and outcomes in patients with advanced non-small cell lung cancer (aNSCLC) post-EGFR tyrosine kinase inhibitor (TKI) therapy [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 933.

Abstract 3418: Alterations in PIK3CA/PTEN as resistance mechanisms in lung cancer patients progressing on first-line next generation EGFR/ALK tyrosine kinase inhibitors

Abstract Introduction: Advent of targeted therapies has deeply changed treatment of advanced oncogene-addicted non-small cell lung cancer (NSCLC), but development of resistance remains a main issue. Given the efficacy of next generation tyrosine kinase inhibitors (TKIs) against on-target mutations, their first-line administration could increase the relevance of off-target resistance mechanisms. Activating PIK3CA mutations and PTEN loss have been described as putative off-target resistance mechanisms across generations of EGFR TKIs. The role of these alterations in the development of resistance to ALK TKIs has been less described. MATCH-R trial (NCT02517892) is an ongoing prospective study whose objective is to understand mechanisms of acquired resistance to cancer therapies and develop strategies to overcome it. Materials and methods: We collected clinical and molecular data of patients (pts) with NSCLC enrolled in the molecular target group (MTG) of MATCH-R trial. We identified pts with EGFR mutations or ALK rearrangements who developed PIK3CA/PTEN alterations in tissue biopsy and/or circulating tumor DNA upon progression to first-line osimertinib/alectinib. We established patient-derived cell lines (PDCL) from the identified MATCH-R pts and we engineered commercial cell lines (CCL) harboring EGFR mutation (PC9) or ALK fusion (H3122) to constitutively express PIK3CA mutations and/or to have a permanent loss of PTEN. Cell viability assays and Western blot studies with different EGFR/ALK/PI3K/mTOR inhibitors were performed. Results: Of the 186 pts with advanced NSCLC included in the MTG of MATCH-R, 110 (59.1%) harbored EGFR mutations (EGFR+) and 27 (14.5%) ALK rearrangements (ALK+). Among them, 19 received first-line osimertinib and seven first-line alectinib. Five and two pts developed PIK3CA/PTEN alterations in the EGFR+ and ALK+ groups, respectively. In the EGFR+ group, PIK3CA E545K (n=2), R108H, N345K and R357Q mutations were detected. PTEN mutations (F437fs*5 and Y27C) were concomitant with E545K and R357Q mutations, respectively. In both ALK+ pts, a PIK3CA E545K mutation was identified, together with PTEN exon 5 splicing in one case. We confirmed on CCL that PIK3CA E545K mutation, alone or in combination with PTEN loss, confers resistance to second-/third-generation EGFR/ALK TKIs. PTEN loss alone had a moderate impact on TKIs sensitivity. Overcoming strategies combining EGFR/ALK TKIs with PIK3CA/mTOR inhibitors are being evaluated and will be disclosed at the meeting. Conclusions: Activating PI3KCA mutations and molecular events leading to PTEN loss are frequent events at resistance to first-line EGFR/ALK TKIs, and can be detected concomitantly. Functional assays confirmed that these alterations act as resistance mechanisms. These observations are of interest as PI3KCA/mTOR inhibitors may have a role in overcoming resistance. Citation Format: Giorgia Guaitoli, Francesco Facchinetti, Juan David Flórez-Arango, Floriane Braye, Hayato Mizuta, Santiago Ponce-Aix, Damien Vasseur, Ken André Olaussen, Stefan Michiels, Mihaela Aldea, Jordi Remon, Fabrice Barlesi, Benjamin Besse, David Planchard, Luc Friboulet. Alterations in PIK3CA/PTEN as resistance mechanisms in lung cancer patients progressing on first-line next generation EGFR/ALK tyrosine kinase inhibitors [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 3418.

Overall survival in advanced epidermal growth factor receptor mutated non-small cell lung cancer using different tyrosine kinase inhibitors in The Netherlands: a retrospective, nationwide registry study.

Clinical guidelines advise osimertinib as preferred first line treatment for advanced epidermal growth factor receptor (EGFR) mutated non-small cell lung cancer (NSCLC) with deletions in exon 19 (del19) or exon 21 L858R mutation. However, for first-line osimertinib the real world overall survival (OS) in mutation subgroups remains unknown. Therefore, the aim of this study was to evaluate the real-world OS of those patients treated with different generations of EGFR-tyrosine kinase inhibitors (TKI), and to identify predictors of survival. Using real-world data from the Netherlands Cancer Registry (NCR) we assessed patients diagnosed with stage IV NSCLC with del19 or L858R mutation between January 1, 2015, and December 31, 2020, primarily treated with then regularly available TKIs (including osimertinib). Between January 1, 2015, and December 31, 2020, 57,592 patients were included in the NCR. Within this cohort we identified 1109 patients, 654 (59%) with del19 and 455 (41%) with L858R mutations, respectively; 230 (21%) patients were diagnosed with baseline brain metastases (BM). Patients were treated with gefitinib (19%, 213/1109), erlotinib (42%, 470/1109), afatinib (15%, 161/1109) or osimertinib (24%, 265/1109). Median OS was superior for del19 versus L858R (28.4 months (95% CI 25.6-30.6) versus 17.7 months (95% CI 16.1-19.5), p<0.001. In multivariable analysis, no difference in survival was observed between various TKIs in both groups. Only in the subgroup of patients with del19 and baseline BM, a benefit was observed for treatment with osimertinib. In this nationwide real-world cohort, survival of Dutch patients with advanced NSCLC and an EGFR del19 mutation was superior versus those harboring an L858R mutation. Osimertinib performed only better as first-line treatment in patients with del19 and BM. None.

Clinical efficacy and prognosis analysis of treatment regimens for EGFR mutant non-small cell lung cancer and brain metastasis: a retrospective study

BackgroundThe aims of the study were to evaluate potential differences among first-line treatment for EGFR mutant (m+) non-small cell lung cancer (NSCLC) patients with brain metastasis in China and to identify the factors influencing survival outcomes.MethodsIn this retrospective study, 172 EGFRm + patients with advanced NSCLC who received a 1st generation EGFR tyrosine kinase inhibitor (TKI) were divided into 4 groups: A, EGFR-TKI (n = 84); B, EGFR-TKI + pemetrexed + cisplatin/carboplatin chemotherapy (CT) (n = 55); C, EGFR-TKI + bevacizumab (n = 15); and D, EGFR-TKI + pemetrexed + cisplatin/carboplatin CT + bevacizumab (n = 18). Intracranial and extracranial progression-free survival (PFS), the overall survival (OS), objective remission rates (ORRs) and adverse events were analyzed.ResultsIntracranial PFS of groups C + D was longer than for groups A + B (18.9 m vs. 11.0 m, P = 0.027). Extracranial PFS were longer in group B in comparison with group A (13.0 m vs. 11.5 m, P = 0.039) and in groups C + D compared to groups A + B (18.9 m vs. 11.9 m, P = 0.008). Median OS in groups A and B were 27.9 m and 24.4 m, respectively, while groups C and D have not yet achieved median OS. Significant difference was found in intracranial ORR between groups A + B vs. C + D (31.0% vs. 65.2%, P = 0.002). Most patients suffered grade 1–2 treatment-related adverse events, which were relieved soon after symptomatic treatment.ConclusionsFirst-generation EGFR-TKI + bevacizumab treatment outperformed other regimens in EGFRm + NSCLC patients with brain metastasis. The therapy improved the control and delayed progression of intracranial lesions and prolonged survival times.

A Real-world Study on the Expression Characteristics of PD-L1 in Patients with Advanced EGFR Positive NSCLC and Its Relationship with the Therapeutic Efficacy of EGFR-TKIs

Epidermal growth factor receptor-tyrosine kinase inhibitors (EGFR-TKIs) is the first choice for first-line treatment of advanced patients with EGFR positive non-small cell lung cancer (NSCLC). For advanced NSCLC patients with negative drive gene and positive programmed cell death ligand 1 (PD-L1) or highly expressed NSCLC patients, the first-line treatment recommends immune checkpoint inhibitors (ICIs) monotherapy or ICIs combined chemotherapy. Therefore, the first-line treatment strategy for advanced NSCLC patients with EGFR positive at different PD-L1 expression levels is worth further exploring. Many previous studies have suggested that the expression of PD-L1 is obviously affected by EGFR mutation, and the expression of PD-L1 is likely to be related to the mechanism of EGFR-TKIs resistance. The purpose of this study was to analyze the expression characteristics of PD-L1 in patients with advanced EGFR positive NSCLC and its relationship with the efficacy of EGFR-TKIs. 159 patients with newly diagnosed advanced NSCLC with EGFR positive (including 141 patients with EGFR sensitive mutations) were enrolled to analyze the relationship between clinicopathological characteristics and PD-L1 expression. The factors affecting the therapeutic effect of EGFR-TKIs in 141 patients with EGFR sensitive mutations were also explored. The PD-L1 expression of the included patients was classified according to the tumor promotion score (TPS): negative (TPS<1%) accounted for 47.2%, low expression (1%≤TPS<50%) accounted for 32.1%, and high expression (TPS≥50%) accounted for 20.7%. Among them, patients with solid predominant cancer cell pathomorphology classification are more likely to have high expression of PD-L1, accounting for 52.9% (P<0.0001). The median progression-free survival (mPFS) of patients with PD-L1 negative expression, low expression and high expression who received first generation EGFR-TKIs treatment were 12.4 months, 10.5 months and 3.7 months, respectively, with significant statistical difference (P<0.0001). During the EGFR-TKIs treatment, patients with a history of radiotherapy for lung lesions have a longer PFS benefit than those without a history of radiotherapy (mPFS: 17.0 months vs 9.3 months, P<0.0001). The expression level of PD-L1 in advanced EGFR positive NSCLC patients was significantly correlated with the pathomorphology classification of cancer cells. The efficacy of EGFR-TKIs in patients with PD-L1 overexpression NSCLC was significantly poor. PFS can be significantly prolonged during targeted therapy combined with radiotherapy of lung lesions.