Common EGFR Research Articles

EXTH-72. INTEGRATED MULTIOMIC ANALYSIS OF ISOGENIC EGFRVIII MODELS OF GBM REVEALS EXPLOITABLE THERAPEUTIC VULNERABILITIES

Abstract Glioblastoma (GBM) is the most common primary malignant brain tumor with an abysmal 15-month median survival. Therefore, novel therapeutic interventions are urgently needed. EGFR is a receptor tyrosine kinase that is mutated in over 50% of GBM and is a logical target for precision oncology approaches. While aberrant EGFR signaling has been successfully targeted in other cancers, early attempts to target EGFR in GBM clinical trials have not been successful. Since these early trials, several studies have revealed that GBM EGFR biology is unique and cannot be generalized from other EGFR-driven neoplasms. To better understand EGFR biology in a GBM-specific context, we have characterized the GBM transcriptome with RNAseq, the epigenome with CUT&RUN, and the kinase proteome with Multiplexed inhibitor beads with Mass Spectrometry (MIB-MS), collectively referred to as ‘multiomics’, after modeling EGFR resistance. An isogenic mouse astrocyte (mAc) model of GBM was genetically engineered to overexpress EGFRvIII (CEv3), the most common EGFR mutation in GBM. Expression of EGFRvIII induces a unique multiomic profile that mediates many hallmark cancer phenotypes including proliferation and stemness. Chronic EGFR resistance was modeled both in vitro and in vivo through continuous exposure to erlotinib or gefitinib, EGFR tyrosine kinase inhibitors (TKI). Additionally, acute EGFR resistance was modeled using a single exposure to EGFR TKI afatinib or neratinib in vitro over a 48-hour time course. Preliminary multiomic characterization of these data has revealed several targets that can be further investigated for therapeutic exploitation. Further investigation into these targets using orthotopic allografts with CEv3 cells shows that combinatorial therapy with neratinib and abemacilib, a CDK inhibitor, significantly (p < 0.001, n= 20 mice per group) extends survival (56 days) compared to neratinib alone (31.5 days). Future integrated multiomic analysis aims to elucidate the synergistic relationship between neratinib and abemacilib.

Non-small cell lung carcinoma with co-expression of TTF1 and p40: a clinicopathological analysis of six cases

Objective: To investigate the clinicopathological features, molecular pathology characteristics, and prognosis of non-small cell lung carcinoma (NSCLC) exhibiting co-expression of p40 and thyroid transcription factor1 (TTF1). Methods: Clinical and pathological data of six NSCLC cases with co-expression of p40 and TTF1 diagnosed at the First People's Hospital of Xiaoshan District, Hangzhou, China from January 2016 to December 2023 were collected. Relevant literature was also reviewed. Results: NSCLC with co-expression of p40 and TTF1 commonly occurred in male smokers and had been in stage Ⅲ-Ⅳ when diagnosis. Microscopic examination revealed that the tumor cells were arranged in solid nests and sheets with marked atypia and visible mitotic figures. There was no prominent evidence of keratinization or glandular formation. The tumor cells diffusely co-expressed p40 and TTF1, exhibiting a dual immunophenotype characteristic of both squamous cell carcinoma and adenocarcinoma. Molecular testing of four NSCLC co-expressing p40 and TTF1 revealed the presence of common EGFR mutations, as well as mutations of NRAS (mutation rate of 2.09%), EML4-ALK (mutation rate of 24.77%), and PIK3CA (exon 10 c.1658 G>C p.S553T, mutation rate of 4.32%). All six tumors were poorly differentiated, highly invasive, and associated with poor prognosis. Four of the six patients experienced widespread metastasis and died within 7 to 30 months after the diagnosis or initial treatment. Conclusions: NSCLC with co-expression of p40 and TTF1 exhibits distinct clinicopathological features, immunophenotypes, molecular alterations, and clinical outcomes, characterized by rapid progression and poor prognosis. Pathologists should be vigilant in recognizing this entity to avoid misdiagnosis and missed diagnosis.

A real‑world study of clinical characteristics, treatment sequence and outcomes of patients with non-small cell lung cancer and EGFR exon 20 insertion mutations.

EGFR exon 20 insertion (EGFRex20ins) mutations are found in up to 4% of all patients with non-small cell lung cancer (NSCLC). These patients are often insensitive to EGFR-tyrosine kinase inhibitors (TKIs) and have worse prognosis than patients with more common EGFR mutations. In this multicenter, retrospective, real-world study, we sought to determine whether the administration of recently approved treatments that specifically target EGFRex20ins mutations could significantly improve outcomes in this patient population. We evaluated the clinical features of 41 patients diagnosed with NSCLC and EGFRex20ins mutations, their evolution, and response to treatments received across 7 hospitals in the Valencian Community, Spain, between 31st December 2012 and 31st December 2022. 32 patients (72%) developed metastatic disease, and 29 (71%) of them received oncological treatment. We found that administering a targeted therapy against EGFRex20ins mutations (amivantamab, mobocertinib and/or sunvozertinib) at some point during the course of treatment, significantly increased the median OS of metastatic patients from 8months (95% CI 0-21.7) to 30months (95% CI 11.1-48.8; Hazard ratio = 0.297, p = 0.02). Our findings contribute to the evolving standard of care for this specific population and highlight the clinical benefits of targeted cancer therapies.

Proteogenomic analysis of air-pollution-associated lung cancer reveals prevention and therapeutic opportunities

Air pollution significantly impacts lung cancer progression, but there is a lack of a comprehensive molecular characterization of clinical samples associated with air pollution. Here, we performed a proteogenomic analysis of lung adenocarcinoma (LUAD) in 169 female never-smokers from the Xuanwei area (XWLC cohort), where coal smoke is the primary contributor to the high lung cancer incidence. Genomic mutation analysis revealed XWLC as a distinct subtype of LUAD separate from cases associated with smoking or endogenous factors. Mutational signature analysis suggested that Benzo[a]pyrene (BaP) is the major risk factor in XWLC. The BaP-induced mutation hotspot, EGFR-G719X, was present in 20% of XWLC which endowed XWLC with elevated MAPK pathway activations and worse outcomes compared to common EGFR mutations. Multi-omics clustering of XWLC identified four clinically relevant subtypes. These subgroups exhibited distinct features in biological processes, genetic alterations, metabolism demands, immune landscape, and radiomic features. Finally, MAD1 and TPRN were identified as novel potential therapeutic targets in XWLC. Our study provides a valuable resource for researchers and clinicians to explore prevention and treatment strategies for air-pollution-associated lung cancers.

Proteogenomic analysis of air-pollution-associated lung cancer reveals prevention and therapeutic opportunities.

Air pollution significantly impacts lung cancer progression, but there is a lack of a comprehensive molecular characterization of clinical samples associated with air pollution. Here, we performed a proteogenomic analysis of lung adenocarcinoma (LUAD) in 169 female never-smokers from the Xuanwei area (XWLC cohort), where coal smoke is the primary contributor to the high lung cancer incidence. Genomic mutation analysis revealed XWLC as a distinct subtype of LUAD separate from cases associated with smoking or endogenous factors. Mutational signature analysis suggested that Benzo[a]pyrene (BaP) is the major risk factor in XWLC. The BaP-induced mutation hotspot, EGFR-G719X, was present in 20% of XWLC which endowed XWLC with elevated MAPK pathway activations and worse outcomes compared to common EGFR mutations. Multi-omics clustering of XWLC identified four clinically relevant subtypes. These subgroups exhibited distinct features in biological processes, genetic alterations, metabolism demands, immune landscape, and radiomic features. Finally, MAD1 and TPRN were identified as novel potential therapeutic targets in XWLC. Our study provides a valuable resource for researchers and clinicians to explore prevention and treatment strategies for air-pollution-associated lung cancers.

EP.06C.06 Outcome and Clinical Profile of Common and Uncommon EGFR Mutations in NSCLC: Retrospective Analysis from an Argentinean Cancer Center

EP.06C.06 Outcome and Clinical Profile of Common and Uncommon EGFR Mutations in NSCLC: Retrospective Analysis from an Argentinean Cancer Center

The Factors Associated With Mutant Epidermal Growth Factor Receptor Positivity in Patients With Lung Cancer: A Study From a Tertiary Care Center in Pakistan.

Objective In this study, we sought to elucidate the relationship between demographic and clinical factors and epidermal growth factor receptor tyrosine kinase (EGFR-TK) positivity in patients with advanced-stage lung cancer at a tertiary care center in Pakistan. Methods This analytical cross-sectional study was conducted from February 2020 to July 2023 at Shaikh Zayed Hospital, Lahore, Pakistan, in collaboration with the Centre of Excellence in Molecular Biology (CEMB), University of the Punjab. The study included 70 consecutive patients with advanced-stage lung cancer, and aimed to identify common EGFR mutations (Exon 19 deletion and Exon 21 L858R mutation), determine their frequency, and correlate EGFR-TK mutation positivity with clinical and non-clinical factors. Tissue acquisition and processing involved bronchoscopy, pleuroscopy, or percutaneous ultrasound-guided lung mass biopsy, followed by molecular analysis using polymerase chain reaction (PCR) extraction, amplification, and sequencing. The study employed convenient sampling and included adults aged over 18 years with histologically confirmed lung cancer. Results We enrolled 70 lung cancer patients, with a mean age of 60.87 years, and a male-to-female ratio of 1.4:1. The majority (61.4%) had adenocarcinoma, and 34.3% harbored a mutant EGFR-TK. EGFR mutations were more common in adenocarcinoma (91.7%) and associated with female non-smokers. Binary logistic regression analysis revealed that age <50 years and adenocarcinoma type were significant predictors of EGFR mutations. We found no significant associations with gender, smoking status, or other variables. These findings have implications for personalized treatment approaches in lung cancerpatients. Conclusions Our study reveals a high frequency of occult EGFR mutations (Exon 19 deletion and Exon 21 L858R mutation) in non-small cell lung cancer (NSCLC) patients, particularly among male smokers and female non-smokers. These findings emphasize the importance of routine EGFR mutation testing to identify patients who may benefit from targeted therapies, ultimately improving treatment outcomes.

1263P Biomarker analysis of plasma samples in YAMATO study: A randomized phase II trial comparing switching treatment of osimertinib following 8 months of afatinib (A) and osimertinib alone (B) in untreated advanced NSCLC patients with common EGFR mutation (TORG1939/WJOG12919L)

1263P Biomarker analysis of plasma samples in YAMATO study: A randomized phase II trial comparing switching treatment of osimertinib following 8 months of afatinib (A) and osimertinib alone (B) in untreated advanced NSCLC patients with common EGFR mutation (TORG1939/WJOG12919L)

Clinicopathological and prognostic implications of EGFR mutations subtypes in Moroccan non-small cell lung cancer patients: A first report.

Non-small cell lung cancer (NSCLC) remains a significant global health concern, with EGFR mutations playing a pivotal role in guiding treatment decisions. This prospective study investigated the prevalence and clinical implications of EGFR mutations in Moroccan NSCLC patients. A cohort of 302 NSCLC patients was analyzed for EGFR mutations using multiple techniques. Demographic, clinical, and pathological characteristics were assessed, and overall survival (OS) outcomes were compared among different EGFR mutation subtypes. EGFR mutations were present in 23.5% of patients, with common mutations (81.69%) dominating. Common mutations showed strong associations with female gender and non-smoking status, while rare mutations were associated with a positive smoking history. Patients with EGFR mutations receiving tyrosine kinase inhibitors (TKIs) had significantly improved OS compared to wild-type EGFR patients. Notably, patients with common EGFR mutations had the highest OS, while those with rare mutations had a shorter survival period, albeit not statistically significant. This study highlights the relevance of EGFR mutation status in NSCLC patients, particularly in therapeutic decision-making. The association between smoking history and rare mutations suggests the need for tailored approaches. The survival advantage for patients with common EGFR mutations underscores the significance of personalized treatment strategies.

Mutation pattern of EGFR gene in Peruvian patients with non-small cell lung cancer.

e20615 Background: The correct characterization of EGFR mutations is crucial to the proper management of NSCLC patients due to the possibility to treat these patients with specific targeted therapies. Herein we report the incidence, mutation pattern and novel mutations of EGFR mutation in Peruvian NSCLC patients. Methods: Between 2016 and 2023 a total of 1489 NSCLC patients from public and private centers were referred to ONCOGENOMICS laboratory for somatic mutation testing. Next Generation Sequencing (NGS) was performed using the Ampliseq for Illumina FOCUS or Custom panel and run on the Illumina MiSeq. Raw data were processed automatically on the BaseSpace Sequence Hub (Illumina) and aligned to the hg19 reference genome The default limit of detection (LOD) was set at 5% allelic frequency (VAF) in tissue samples and 0.5% VAF in cfDNA samples. Results: The study included 1401 NSCLC patients, 61.8% were women. Clinical stages were distributed III (22.5%), IV (77.5%). All tumors were adenocarcinoma. Incidence of EGFR-mutated NSCLC was 33.4% (450), 68.9% were women. We found 519 EGFR mutations in 450 tumors. Classical or common EGFR mutations; L858R or ex19del corresponded to 86.4% with 331 and 383 cases, respectively and L858R or ex19del + T790M corresponded to 13.6% with 2 cases onset and 50 cases in progression. EGFR T790M de novo mutations were found in 4 cases onset. In one case at diagnosis was detected a T790M-like 3R mutant EGFR p.(C797S); c.2390G &gt; C, a drug resistance point mutation in ex20.Non-classical or atypical EGFR mutations corresponded to 14.0% (63/450) of cases. Non-classical EGFR mutations were categorized as follows according to Janning et al.: (i) More frequent uncommon EGFR mutations - 39.7% (25/63) including G719X, S768I, E709X and L861Q (22/25); G719X + S768I (1/25); and combinations with classical EGFR mutation L858R + S768I (2/25). (ii) EGFR exon 20 insertions - 44.5% (28/63), including a novel mutation EGFR p.(769_770VDinsGFV);c.2308_2309ins. All were located in the loop following the C-helix. And (iii) very rare mutations - 15.9% (10/63) including very rare point mutations in ex19 (1/10), ex18del (4/10), ex19ins (1/10) and complex mutations (ex19del + very rare point mutation in ex19 (4/10).Two point mutation no reported previously were found, EGFR, ex19, p.(S752F);c.2255C &gt; T and EGFR, ex19, p.(T751P);c.2251A &gt; C, both as co-mutations with classical EGFR ex19del mutation. Conclusions: The present study underscores the value of NGS to optimally address EGFR mutations, specially the rare and novel ones due to its higher sensitivity and specificity compared to other techniques. This approach is particularly important for the Latin American population which is underrepresented in genomic databases. Clinical correlation of this genomic findings is ongoing.

A randomized phase II trial of 8 months of afatinib switching to osimertinib (A) versus osimertinib alone (B) as first-line treatment in advanced NSCLC patients with common EGFR mutation: YAMATO study (TORG1939/WJOG12919L).

8574 Background: NSCLC with common EGFR mutation (L858R or exon 19 deletion (Del19)) is known to originally comprise small portion of uncommon and compound EGFR variant cells including T790M-mutant ones albeit treatment-naïve. To overcome concomitant heterogeneous EGFR mutations, we planned a randomized phase II trial to assess the strategy of switching to osimertinib following 8 months of afatinib compared with osimertinib alone. Methods: YAMATO study is an open-label, multi-center, randomized phase II study. Patients with newly diagnosed stage III/IV/recurrent NSCLC harboring EGFR activating mutations (L858R or Del19) were randomized in a 1:1 ratio to receive up-front 8 months of afatinib (30 mg or 40 mg QD) followed by osimertinib (80 mg QD) (arm A) or osimertinib (80mg QD) alone (arm B) until disease progression or intolerable toxicity. The primary endpoint is 2-year progression free survival (PFS) rate with threshold rate of 22% and expected rate of 40% (one-tailed alpha of 0.1, beta of 0.2). Secondary endpoints are objective response rate (ORR), PFS, time to treatment failure, overall survival and adverse events. Results: Between May 2020 and Apr 2021, 113 patients were enrolled from 27 institutions (A/B 56/57). Patient characteristics were as follows: median ages, 73.5/71 years (range 41-85/41-92 years); proportion of males, 42.9/35.1%; EGFR mutation types, L858R/Del19 59/41% in A, 58/42% in B. The difference of two-year PFS rate was not observed statistically significant between groups (37.3% [80% CI, 29.0 to 45.5] in arm A vs 47.4% [80% CI, 38.5 to 55.7] in arm B; p=0.44; HR:1.28 [80% CI, 0.95-1.73]). The ORR was 82% in arm A and 87% in arm B. With the median follow-up of 27.5 months, median PFS was 16.8 months in arm A, and 22.2 months in arm B (HR: 1.280, p = 0.29). Severe pneumonitis occurred in 7% in arm A, most of which developed after switching to osimertinib, and 1.8% in arm B. Conclusions: YAMATO study failed to demonstrate the superiority of EGFR-TKI switching therapy of 8 months afatinib to osimertinib over osimertinib alone in terms of 2-year PFS rate in untreated advanced NSCLC patients with common EGFR mutations. Clinical trial information: 031200021 .

High-dose furmonertinib in combination with intraventricular chemotherapy for EGFR exon 20 insertion mutated lung adenocarcinoma with leptomeningeal metastasis.

e20555 Background: Leptomeningeal metastasis (LM) is a severe complication of advanced lung adenocarcinoma (LUAD) and always has a dismal prognosis. EGFR exon 20 insertion ( EGFR 20ins) is the third most common EGFR mutations; however, there are currently no reports focusing on LM with EGFR 20ins, and the optimal therapy for these patients remains unclear. This retrospective study aimed to evaluate the efficacy and safety of high-dose furmonertinib in combination with intraventricular chemotherapy in EGFR 20ins mutated LUAD patients with LM. Methods: Weretrospectively enrolled 10 LUAD patients with LM who had failed multiline treatment between May 2021 and June 2023 at Nanjing Chest Hospital. All of them had confirmed EGFR 20ins by next generation sequencing. All patients received furmonertinib in combination with intraventricular chemotherapy via the Ommaya reservoir. Furmonertinib was taken at 160 mg once daily. The chemotherapy regimen consisted of 30mg pemetrexed and 5 mg dexamethasone administered twice weekly for 2 weeks during the consolidation phase, followed by a maintenance phase every 3-4 weeks until disease progression or unacceptable toxicity, or patient refusal. Results: The median age was 53.5 years (range: 39-66), and six (60%) were males. Four patients (40%) had an ECOG of 3, and six patients (60%) had an ECOG of 4. The intracranial ORR (iORR) was 60% (6/10) and intracranial DCR (iDCR) was 90% (9/10). The ECOG PS improved in 80% patients after treatment. With a median follow-up of 9.3 months, the median intracranial progression-free survival (iPFS) was 7.3 months (95% CI, 3.3-NR) and the median overall survival (OS) was 8.8 months (95% CI, 4.9-NR), respectively. Treatment related adverse events of ≥ grade 3 occurred in only 2 patients, which were nausea and rash. Conclusions: Furmonertinib in combination with intraventricular chemotherapy is a tolerable treatment with breakthrough clinical efficacy for LUAD patients with LM harboring EGFR 20ins.

BDTX-189, a novel tyrosine kinase inhibitor, inhibits cell activity via ERK and AKT pathways in the EGFR C797S triple mutant cells

The tertiary mutation C797S in the structural domain of the EGFR kinase is a common cause of resistance to third-generation EGFR tyrosine kinase inhibitors (TKIs). In this study, we used a potent, selective and irreversible inhibitor, BDTX-189, to target EGFR C797S triple mutant cells for cell activity. The study constructed the H1975–C797S (EGFR L858R/T790 M/C797S) cell line using the Lentiviral infection/Cas9 method and investigated its potential as a fourth-generation tyrosine kinase inhibitor via chemosensitivity approach. The results demonstrated its ability to induce cytotoxic effects, and inhibit EGFR L858R/T790 M/C797S cell growth and proliferation in a dose-dependent manner. Meanwhile, BDTX-189 reduces the protein phosphorylation levels of EGFR, ERK, and AKT, promoting apoptosis. Furthermore, BDTX-189 not only inhibits common EGFR triple mutations but also effectively inhibits EGFR L858R mutation and EGFR L858R/T790 M mutation. These findings support the cytotoxic effect of BDTX-189 and its inhibitory effect on cell division and proliferation with the EGFR C797S triple mutation.

Abstract CT282: MK-2870-004: A phase 3 study of MK-2870 (SKB264) versus chemotherapy for previously treated advanced or metastatic nonsquamous non-small-cell lung cancer (NSCLC) with EGFR mutations or other genomic alterations

Abstract Background: Trophoblast cell-surface antigen 2 (TROP2), a cell surface glycoprotein involved in the regulation of tumor growth and invasion, is broadly expressed and upregulated in several cancers, including NSCLC. MK-2870 (SKB264) is an antibody-drug conjugate (ADC) composed of the humanized anti-TROP2 monoclonal antibody, a hydrolytically cleavable linker, and the cytotoxic drug KL610023. MK-2870 has demonstrated encouraging antitumor activity and manageable toxicity in phase 1 and 2 studies of patients with solid tumors, including heavily pretreated EGFR-mutant NSCLC. We describe the design of the ongoing phase 3 MK-2870-004 study (NCT06074588) that will evaluate the efficacy and safety of MK-2870 vs chemotherapy for previously treated advanced or metastatic nonsquamous NSCLC with EGFR mutations or other genomic alterations. Trial design: The global, randomized, open-label, phase 3 MK-2870-004 study will enroll ~556 patients, including 456 with exon 19del or L858R EGFR mutations, and 100 with other genomic alterations. Eligible patients are aged ≥18 years with histologically or cytologically documented advanced (stage III not eligible for resection or curative radiation) or metastatic nonsquamous NSCLC with exon 19del or exon 21 L858R EGFR mutations or other genomic alterations in ALK, ROS1, BRAF V600E, NTRK, MET exon 14 skipping, or RET and those with less common EGFR mutations (exon 20 S768I, exon 21 L861Q, and/or exon 18 G719X). Patients must have progressive disease on or after 1 or 2 lines of prior tyrosine kinase inhibitor (TKI) therapy and a platinum-based therapy (may contain anti-PD-[L]1), measurable disease per RECIST v1.1, an available tumor sample, and adequate organ function. Prior EGFR TKI therapy must include a third-generation TKI for patients with T790M EGFR-mutant NSCLC. Patients with active central nervous system metastases or carcinomatous meningitis are ineligible, although those with previously treated and untreated stable brain metastasis are eligible for enrollment. Patients will be randomized (1:1) to MK-2870 4 mg/kg Q2W on Days 1, 15, and 29 of every 6-week cycle, or chemotherapy (docetaxel 75 mg/m2 Q3W or pemetrexed 500 mg/m2 Q3W) on Days 1 and 22 of every 6-week cycle. Randomization will be stratified by EGFR mutations with prior third generation TKI vs EGFR mutations with no prior third generation TKI vs other genomic alterations, brain metastasis (yes vs no), and TROP2 expression (low vs medium vs high). Dual primary endpoints are PFS (per RECIST v1.1 by blinded independent central review) and OS in patients with EGFR-mutant NSCLC. Key secondary endpoints include PFS and OS in all patients with NSCLC, ORR, DOR, patient-reported outcomes, and safety. Enrollment started in November 2023 and is currently ongoing. Citation Format: Federico Cappuzzo, Edward B. Garon, Myung-Ju Ahn, Shun Lu, Terufumi Kato, Enriqueta Felip, Parneet Cheema, Nicolas Girard, Mark Shamoun, Guoqing Wang, Bin Zhao, Rina Hui. MK-2870-004: A phase 3 study of MK-2870 (SKB264) versus chemotherapy for previously treated advanced or metastatic nonsquamous non-small-cell lung cancer (NSCLC) with EGFR mutations or other genomic alterations [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 CT282.

Abstract 6511: BPI-520105, a highly potent, CNS-penetrant 4th generation EGFR inhibitor overcoming major EGFR resistance mutations in NSCLC

Abstract EGFR activating mutations are prevalent in 10-50% of NSCLC patients. The most common EGFR mutations, L858R (L) and Del19 (D), initially respond to first-, second-, or third-generation (1G, 2G and 3G) EGFR-TKIs. However, on-target resistance, primarily by T790M (T) and C797X(C), inevitably emerges post-treatment and leads to disease progression. Different treatment sequence give rise to different complex mutations. In patients resistant to the 3G TKI osimertinib, double mutations L858R/C797X or Del19/C797X (LC or DC) were observed at a frequency of up to 12% after first-line osimertinib, and triple mutations L858R/T790M/C797S or Del19/T790M/C797S (LTC or DTC) were up to 20% after second-line osimertinib. There are no approved targeted therapy options for these complex resistant mutations. In this study, we developed BPI-520105, a 4th generation EGFR inhibitor capable of targeting all aforementioned major forms of EGFR activating and resistance mutations in NSCLC. It might be an optimal way to address this urgent medical need. In vitro, BPI-520105 potently inhibited the activity of a variety of EGFR kinases, as well as inhibited the proliferation and EGFR phosphorylation in cell lines bearing relative mutations, including single (D, L), double (DT, LT, and DC, LC) and triple (LTC, DTC) mutations. Meanwhile, BPI-520105 exhibited relative weakness towards wild type EGFR and IGF1R, demonstrating good selectivity in kinase and cell-based assays. Despite being a reversible EGFR inhibitor, BPI-520105 sustained the inhibition of pEGFR and pERK for up to 24 hours in the western blot assay. In vivo, oral administration of BPI-520105 displayed significant dose-dependent antitumor effect in multiple EGFR mutant xenograft models, including HCC827 (D), NCI-H1975 (LT), BaF3-EGFR-LC/DC, and BaF3-EGFR-LTC models. Remarkably, BPI-520105 significantly prolonged the lifespan of mice with brain orthotropic BaF3-EGFR-DTC-Luc2 allografts, demonstrating its activity towards brain metastasis. Additionally, BPI-520105 exhibited favorable ADME properties, with high oral exposure across various preclinical species. In summary, BPI-520105 is a highly potent, CNS-penetrant, wide type sparing, and orally bioavailable 4th generation EGFR inhibitor, holding promise for the treatment of NSCLC patients with resistance mutations post 3G progression or even at front line. Citation Format: Jing Guo, Lijia Liu, Xiangyong Liu, Bang Fu, Guangcan Bai, Changyong Qiu, Wei Ren, Xiaodong Song, Guolong Du, Xiao Sun, Yongchun Zhang, Weidong Cai, Pingping Wang, Haibo Chen, Xiaoyun Liu, Zhengyao Zou, Jiayu Zhao, Xuepeng Jv, Hong Lan, Lieming Ding, Jiabing Wang. BPI-520105, a highly potent, CNS-penetrant 4th generation EGFR inhibitor overcoming major EGFR resistance mutations in 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 6511.

Abstract 1945: Mechanisms of acquired resistance to EGFR tyrosine kinase inhibitor osimertinib and KRAS-G12C inhibitor sotorasib in lung cancer

Abstract A series of molecular targeted drugs have been developed for the treatment of non-small cell lung cancer (NSCLC) harboring driver gene alterations. Although the use of these drugs has substantially improved the clinical outcomes of patients with the genetically altered NSCLC, these patients ultimately develop resistance to the drugs. Various molecular mechanisms of resistance to the molecular target therapies have been reported, it is still a crucial challenge to overcome the drug resistance. Osimertinib, the most used third-generation EGFR tyrosine kinase inhibitor to target both common EGFR mutations and secondary T790M mutation, and sotorasib, a recently developed KRAS inhibitor to target KRAS G12C mutation, are no exception. In this study, we aimed to investigate the mechanisms of acquired resistance to osimertinib and sotorasib in NSCLC by profiling drug-resistant lung cancer cell lines, which were established from EGFR-mutant HCC827(del E756_A750) and KRAS G12C-mutant H23 through exposure to each of the molecular targeted drugs. Phospho-RTK array and western blot analyses revealed MET overexpression and phosphorylation in the osimertinib-resistant HCC827 (HCC827OR) as previous studies reported. Notably in our study, HCC827OR cells were incompletely sensitive to a selective MET inhibitor savolitinib without osimertinib, suggesting that HCC827OR partially lost its dependency on mutant EGFR and got addiction to MET signaling. When sotolasib was administered to the sotolasib-resistant H23 (H23SR) cells, KRAS-GTP, and the downstream ERK and AKT phosphorylation were suppressed. To identify novel mechanisms of the resistance, we performed epigenomic profiling of active enhancer in those cells and found a candidate transcription factor, at whose gene locus H3K27 acetylation signal was increased in H23SR cells compared to parent H23 cells. Immunoblotting showed that protein expression of the gene was indeed higher in H23SR cells than the parent cells. To confirm the involvement of this gene to the resistance, further investigation is warranted. Citation Format: Yuri Yagami, Takashi Sato, Hiroki Yamamoto, Masayuki Shirasawa, Yoshiro Nakahara, Watanabe Hideo, Naoki Katsuhiko. Mechanisms of acquired resistance to EGFR tyrosine kinase inhibitor osimertinib and KRAS-G12C inhibitor sotorasib in lung cancer [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 1945.

Differential efficacy of tyrosine kinase inhibitors according to the types of EGFR mutations and agents in non-small cell lung cancer: a real-world study

BackgroundBoth first and second-generation EGFR-TKIs are recommended in advanced NSCLC with common EGFR mutations. However, there are few data on the difference in efficacy of EGFR-TKIs based on the type of EGFR mutation and agents.MethodsThis retrospective real-world study evaluated the outcomes and clinicopathologic characteristics, including the type of EGFR mutations, of 237 advanced NSCLC patients treated with first- or second-generation (afatinib) EGFR-TKIs as first-line therapy.ResultsThe median progression-free survival (PFS) and overall survival (OS) of all patients were 11 months (M) and 25M, respectively. In the univariate analysis, patients with exon 19 deletion (del) (n=130) had significantly longer median OS compared to those with other mutations (L858R: 84, others: 23) (30 vs. 22 M, p=0.047), without a difference in PFS (p=0.138). Patients treated with afatinib (n=60) showed significantly longer median OS compared to those treated with first-generation TKIs (gefitinib: 159, erlotinib: 18) (30 vs. 23 M, p=0.037), without a difference in PFS (p=0.179). In patients with exon 19 del, there was no significant difference in median PFS (p=0.868) or OS (p=0.361) between patients treated with afatinib and those treated with first-generation TKIs, while significantly better PFS (p=0.042) and trend in OS (p=0.069) were observed in patients receiving afatinib in other mutations. Exon 19 del was independently associated with favorable OS (p=0.028), while age >70 years (p=0.017), ECOG performance status ≥2 (p=0.001), primary metastatic disease (p=0.007), and synchronous brain metastasis (p=0.026) were independent prognostic factors of poor OS.ConclusionsThe EGFR exon 19 del was associated with favorable OS in advanced NSCLC patients receiving first-line EGFR-TKIs. Moreover, in patients with exon 19 del, first-generation TKIs seem to be a reasonable treatment option if osimertinib is unavailable.

Clinical and molecular characteristics associated with high PD-L1 expression in EGFR-mutated lung adenocarcinoma.

Recent evidence suggests that elevated levels of PD-L1 expression may be linked to early resistance to TKI and reduced survival in NSCLC with EGFR mutations. This study aimed to characterize the clinical and molecular features of EGFR-mutated lung adenocarcinomas and determine the prognostic significance associated with high PD-L1 expression. We conducted a retrospective chart review of 103 consecutive patients with advanced EGFR-mutated NSCLC, who received treatment between 01/01/2016 and 30/12/2020, at our institution. Among the tumors, 17% (n = 18) exhibited high PD-L1 expression (≥50% tumor proportion score), which was associated with a lower prevalence of common EGFR mutations (56% vs. 82%, p = 0.03) and a higher frequency of complex EGFR mutations (28% vs. 7%, p = 0.02). Univariate analysis did not reveal any significant differences in first-line response, progression-free survival, or overall survival between the PD-L1 ≥50% and <50% groups. However, multivariate analysis demonstrated that PD-L1 ≥50% was independently associated with shorter survival (HR = 2.57; 95%CI[1.20-5.55]; p = 0.02), along with male gender (HR = 2.77; 95%CI[1.54-4.19]; p<0.005), presence of liver metastases (HR = 5.80; 95%CI[2.86-11.75]; p<0.005) or brain metastases (HR = 1.99; 95%CI[1.13-3.52]; p = 0.02), and poor general condition at diagnosis (ECOG 3 and 4) (HR = 10.69; 95% CI[4.42-25.85]; p<0.005). Additionally, a trend towards a higher frequency of de novo resistance was observed in the PD-L1 >50% group (7% vs. 17%, p = 0.19). High PD-L1 expression was more commonly found in lung adenocarcinomas with uncommon and complex EGFR mutations. Furthermore, high PD-L1 expression independently predicted poor survival. These findings warrant validation through prospective studies.

Abstract C151: BLU-451 is a CNS-penetrant, wild-type-sparing EGFR inhibitor with broad coverage of uncommon EGFR mutations across structure-based subsets

Abstract Introduction: Uncommon EGFR mutations in non-small cell lung cancer (NSCLC), including exon 20 insertion and atypical mutations, are generally associated with poorer clinical outcomes than common EGFR mutations. Patients (pts) with these mutations have limited effective therapeutic options. Afatinib is the only approved agent for uncommon mutations but is associated with high rates of toxicity and limited central nervous system (CNS) penetration. Amivantamab and mobocertinib are approved for patients with relapsed EGFR exon 20 insertion NSCLC but are associated with limitations in efficacy and CNS activity. BLU-451 is an investigational, CNS-penetrant, EGFR-wild-type (WT)–sparing, selective inhibitor against exon 20 insertion and uncommon EGFR mutations that is currently being evaluated in the phase 1/2 CONCERTO study (NCT05241873). Here, we report on the prevalence of uncommon EGFR mutations from a single center, real-world data set (MD Anderson Cancer Center [MDACC]), and report preclinical activity of BLU-451 on a broad spectrum of uncommon EGFR mutations by structure classification. Methods: BLU-451 cellular activity was evaluated in engineered BaF3 cell lines expressing 62 EGFR kinase domain mutations as well as in cell lines dependent on WT EGFR, using the CellTiter-Glo® Luminescent Cell Viability Assay and a phosphorylation-specific EGFR AlphaLISA® assay. The MDACC Moon Shot™ Genomic Marker-Guided Therapy Initiative (GEMINI) database was searched for pts with NSCLC whose tumors harbored EGFR kinase domain mutations. Results: In the MDACC GEMINI database, a total of 1495 unique patients with NSCLC harboring EGFR mutations were identified, including 1025 with classical mutations (exon 19 deletion and L858R) with or without T790M, 223 with exon 20 insertion mutations, and 247 with only atypical mutations. In BaF3 cells, BLU-451 demonstrated nanomolar potency in multiple atypical and exon 20 insertion mutation cell lines with selectivity against WT EGFR. Conclusion: Atypical EGFR mutations represent a sizable NSCLC pt population, of similar magnitude to that of EGFR exon 20 insertion mutations. BLU-451 preclinical data in EGFR atypical and exon 20 insertion mutations showed broad, potent, and selective activity, supporting continued evaluation of BLU-451 in the phase 1/2 CONCERTO study in pts with advanced or metastatic NSCLC harboring uncommon EGFR mutations. Citation Format: Xiuning Le, Yves Millet, Monique Nilsson, Aditya Dhande, Jeffrey Keats, Holly Ponichtera, Joseph Kim, Junqin He, Yasir Y. Elamin, John V. Heymach, Chiara Conti, Stephanie Lee. BLU-451 is a CNS-penetrant, wild-type-sparing EGFR inhibitor with broad coverage of uncommon EGFR mutations across structure-based subsets [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 C151.

The Impact of On-Target Resistance Mediated by EGFR-T790M or EGFR-C797S on EGFR Exon 20 Insertion Mutation Active Tyrosine Kinase Inhibitors

IntroductionMechanisms of resistance to EGFR exon 20 insertion mutation active inhibitors have not been extensively studied in either robust preclinical models or patient-derived rebiopsy specimens. We sought to characterize on-target resistance mutations identified in EGFR exon 20 insertion-mutated lung cancers treated with mobocertinib or poziotinib and evaluate whether these mutations would or would not have cross-resistance to next-generation inhibitors zipalertinib, furmonertinib, and sunvozertinib. MethodsWe identified mechanisms of resistance to EGFR exon 20 insertion mutation active inhibitors and then used preclinical models of EGFR exon 20 insertion mutations (A767_V769dupASV, D770_N771insSVD, V773_C774insH) plus common EGFR mutants to probe inhibitors in the absence/presence of EGFR-T790M or EGFR-C797S. ResultsMobocertinib had a favorable therapeutic window in relation to EGFR wild type for EGFR exon 20 insertion mutants, but the addition of EGFR-T790M or EGFR-C797S negated the observed window. Zipalertinib had a favorable therapeutic window for cells driven by EGFR-A767_V769dupASV or EGFR-D770_N771insSVD in the presence or absence of EGFR-T790M. Furmonertinib and sunvozertinib had the most favorable therapeutic windows in the presence or absence of EGFR-T790M in all cells tested. EGFR-C797S in cis to all EGFR mutations evaluated generated dependent cells that were resistant to the covalent EGFR tyrosine kinase inhibitors mobocertinib, zipalertinib, furmonertinib, sunvozertinib, poziotinib, and osimertinib. ConclusionsThis report highlights that poziotinib and mobocertinib are susceptible to on-target resistance mediated by EGFR-T790M or -C797S in the background of the most prevalent EGFR exon 20 insertion mutations. Furmonertinib, sunvozertinib, and to a less extent zipalertinib can overcome EGFR-T790M compound mutants, whereas EGFR-C797S leads to covalent inhibitor cross-resistance—robust data that support the limitations of mobocertinib and should further spawn the development of next-generation covalent and reversible EGFR exon 20 insertion mutation active inhibitors with favorable therapeutic windows that are less vulnerable to on-target resistance.