Generation Epidermal Growth Factor Receptor Tyrosine Kinase Inhibitors Research Articles

1055P The gene landscape of lung adenocarcinoma patients with progressive disease of the leptomeninges

The epidermal growth factor receptor tyrosine kinase inhibitors (EGFR-TKIs) provide a better prognosis in EGFR-mutant non-small cell lung cancer (NSCLC). Still, the outcome of leptomeningeal metastasis (LM) remains poor. In addition, due to the limited access to intracranial tumor tissue, gene alterations associated with leptomeningeal metastasis from lung adenocarcinoma (LM-LUAD) are unclear. 45 LM-LUAD from May 2019 to June 2021 in the Guangdong Sanjiu Brain Hospital enrolled in this study. 75% (34/45) of patients with LM harboring EGFR mutation, patients with progressive disease (PD) of LM have 3rd generation EGFR-TKI therapy, defined as Cohort 1; without 3rd generation, EGFR-TKI therapy, defined as Cohort 2. Next-generation targeted panel sequencing (NGS) was performed in each cerebrospinal fluid (CSF) sample of the two cohorts, and 9/45 LM-LUAD patients have matched plasma (PLA). The common gene alterations discovered in CSF of LM-LUAD were EGFR mutation (34/45, 75%), TP53 (25/45, 56%), CDKN2A (9/45, 20%), ALK (7/45, 16%), CTNNB1 (6/45, 13%), MET (5/45, 11%), APC (4/45, 9%), FGF4 (4/45, 9%), FGF3 (4/45, 9%), ERBB2 (4/45, 9%), PIK3CG (4/45, 9%). Co-occurring mutations of TP53 and EGFR were found in 49% (22/45) patients and correlated with poor prognosis. CDKN2A mutation was identified in 20% (9/45) patients and presented slightly shorter OS than those without (OS, 7.1 versus 8.8 months, p=0.2). Cohort 1 has more genes associated with poor prognosis, consisting of CDK4, CDKN2A, PIK3CG, or PIK3CA, and YES1 and MET were more likely to be detected in cohort 2. The alternation of EGFR was comparable between CSF and matched PLA. Incidences of gene alterations such as (CDK4, CDKN2A, MET, APC, KRAS, FGFR3, JAK2, BRAF, PIK3CG) more likely identified in CSF. All the mutant allele frequency (MAF) were much higher in CSF compared to matched PLA. CSF could be a potential candidate for the genetic profiling of LM-LUAD, demonstrating the genetic characteristic of LM in EGFR-mutated lung adenocarcinoma on diversity EGFR-TKI therapy.

EP08.02-038 Study of First-Line Aumolertinib Plus Bevacizumab and Pemetrexed Treated NSCLC with EGFR Mutation and Brain Metastasis

Brain metastases (BMs) are common among patients with lung cancer and have been associated with treatment failure and limited survival. Approximately 25% of NSCLC patients present with BMs at first diagnosis. Patients treated with 3rd generation EGFR-tyrosine kinase inhibitors (TKIs), including aumolertinib and osimertinib, showed a lower risk of progression and better responses with EGFRm NSCLC and BMs. Studies suggested EGFR-TKI plus bevacizumab had PFS benefits for patients with CNS metastases, and combination strategies of chemotherapeutic agents and TKI also demonstrated the potential to improve survival.

A Multicenter Two-arm, Phase II Trial Assessing the Safety and Efficacy of First-line Lazertinib and Locally Ablative Radiotherapy in Patients With Synchronous Oligo-metastatic EGFR-mutant Non-small Cell Lung Cancer (ABLATE, KCSG-LU21-11)

BackgroundThe current standard treatment of advanced non-small cell lung cancer (NSCLC) patients with epidermal growth factor receptor (EGFR) mutation is upfront EGFR targeted therapy. However, patients invariably experience disease progression at primary tumors or metastatic sites. Adding stereotactic body radiation therapy (SBRT) to systemic therapy can improve progression-free survival (PFS) and overall survival (OS). This multicenter, 2-arm, phase II study aims to evaluate the efficacy and safety of lazertinib, a third generation EGFR tyrosine kinase inhibitor, combined with upfront locally ablative radiotherapy in EGFR-mutant NSCLC patients with synchronous oligometastatic disease (ClinicalTrials.gov: NCT05167851). Patients and MethodsKey inclusion criteria are biopsy-proven EGFR-mutated adenocarcinoma with synchronous, oligometastatic (≤5 metastases) NSCLC. Patients will be randomized 1:1 to receive lazertinib or lazertinib + SBRT to the primary tumor and metastatic sites. The primary endpoint is PFS according to RECIST: Response Evaluation Criteria in Solid Tumor version 1.1, and the secondary endpoints are OS, objective response rate, and safety. ResultsPatient enrolment began in January 2021 and is ongoing at 7 sites in the Republic of Korea. ConclusionThis trial will provide valuable information on the efficacy and safety of lazertinib in combination with SBRT in patients with synchronous, oligometastatic EGFR-mutant NSCLC.

Genotyping of cerebrospinal fluid in lung cancer patients with leptomeningeal metastasis.

BackgroundThe prognosis of non–small‐cell lung cancer (NSCLC) with leptomeningeal metastasis (LM) is poor. Detection of cell‐free DNA (cfDNA) by next generation sequencing (NGS) in cerebrospinal fluid (CSF) may facilitate diagnosis of LM and identification of drug resistance mechanisms, yet its clinical use needs to be further verified.MethodsWe performed a retrospective cohort study to assess the genetic profiles of paired CSF and plasma samples in lung cancer patients with LM. Of 17 patients screened, a total of 14 patients with LM and paired NGS tests were enrolled.ResultsAll patients harbor driver gene mutations, including 12 epidermal growth factor receptor (EGFR) activating mutations, 1 anaplastic lymphoma kinase (ALK) rearrangement, and 1 ROS‐1 fusion. Genetic mutations were detected in CSF cfDNA from 92.9% patients (13/14), which was significantly higher than that from the plasma (9/14, 64.2%). The mutations were highly divergent between CSF and plasma cfDNA, with a concordance rate of 24.38% and 10 mutations shared by the two media. CSF cfDNA could also benefit the analysis of resistance mechanisms to targeted therapies. In five patients who experienced progression on 1st or 2nd generation EGFR‐tyrosine kinase inhibitors (TKIs), RB1 mutation, and amplification of MET and EGFR were detected in CSF cfDNA only. In eight patients with LM progression on osimertinib resistance, EGFR amplification was detected in CSF cfDNA from four patients, whereas no CNVs were detected in the matched plasma samples.ConclusionsIn conclusion, CSF could be superior to plasma in providing a more comprehensive genetic landscape of LM to find out drug resistance mechanisms and guide subsequent treatments.

Structural basis for the selectivity of 3rd generation EGFR inhibitors: a molecular dynamics study

Activating mutations in the EGFR kinase domain are known to be a common cause of Non-Small Cell Lung Cancer (NSCLC) and are thus targeted for treatment. First generation Tyrosine Kinase Inhibitors (TKIs) were used to treat NSCLC patients with the known activating mutations L858R and exon 19 deletion but were resisted by a second mutation T790M in the active site of the kinase domain. Second generation members of TKIs have an electrophilic moiety that can form a covalent bond with Cys797 and are effective against T790M EGFR but are toxic because they inhibit WT EGFR as well. Third generation TKIs, like Osimertinib, can bind to and irreversibly inhibit T790M mutants selectively, while sparing the wild-type enzyme. Thus, they possess a better safety profile and a wider therapeutic window. However, the reason behind their selectivity is still not well understood. In this study, computational MD simulations were carried out on Osimertinib in complex with both WT and L858R/T790M Double Mutant (DM) EGFR to provide an insight into the selectivity of Osimertinib and its molecular interactions within the active site. A high-resolution trajectory analysis showed that the key selectivity residues are Val726, met793, and Cys797. Interaction of Osimertinib with these residues is improved due to the T790M mutation which optimizes the ligand orientation for binding, as evident from the RMSD and the distances monitored. These results can provide guidance for the development of more selective 3rd generation EGFR TKIs. Communicated by Ramaswamy H. Sarma

Physiologically Based Pharmacokinetic (PBPK) Modeling to Predict PET Image Quality of Three Generations EGFR TKI in Advanced-Stage NSCLC Patients.

Introduction: Epidermal growth factor receptor (EGFR) mutated NSCLC is best treated using an EGFR tyrosine kinase inhibitor (TKI). The presence and accessibility of EGFR overexpression and mutation in NSCLC can be determined using radiolabeled EGFR TKI PET/CT. However, recent research has shown a significant difference between image qualities (i.e., tumor-to-lung contrast) in three generation EGFR TKIs: 11C-erlotinib, 18F-afatinib and 11C-osimertinib. In this research we aim to develop a physiological pharmacokinetic (PBPK)-model to predict tumor-to-lung contrast and as a secondary outcome the uptake of healthy tissue of the three tracers. Methods: Relevant physicochemical and drug specific properties (e.g., pKa, lipophilicity, target binding) for each TKI were collected and applied in established base PBPK models. Key hallmarks of NSCLC include: immune tumor deprivation, unaltered tumor perfusion and an acidic tumor environment. Model accuracy was demonstrated by calculating the prediction error (PE) between predicted tissue-to-blood ratios (TBR) and measured PET-image-derived TBR. Sensitivity analysis was performed by excluding each key component and comparing the PE with the final mechanistical PBPK model predictions. Results: The developed PBPK models were able to predict tumor-to-lung contrast for all EGFR-TKIs within threefold of observed PET image ratios (PE tumor-to-lung ratio of −90%, +44% and −6.3% for erlotinib, afatinib and osimertinib, respectively). Furthermore, the models depicted agreeable whole-body distribution, showing high tissue distribution for osimertinib and afatinib and low tissue distribution at high blood concentrations for erlotinib (mean PE, of −10.5%, range −158%–+190%, for all tissues). Conclusion: The developed PBPK models adequately predicted the image quality of afatinib and osimertinib and erlotinib. Some deviations in predicted whole-body TBR lead to new hypotheses, such as increased affinity for mutated EGFR and active influx transport (erlotinib into excreting tissues) or active efflux (afatinib from brain), which is currently unaccounted for. In the future, PBPK models may be used to predict the image quality of new tracers.

Abstract 3346: BBT-207, a novel, 4th generation, epidermal growth factor receptor (EGFR) tyrosine kinase inhibitor (TKI) with broad-spectrum activity to both treatment-emergent and drug-naïve mutants for the treatment of NSCLC

Abstract Background: Activating mutations in EGFR, e.g., L858R (L) and Del19 (D), are observed in 14.1-32.3% of NSCLC worldwide and defines a druggable entity. Single agent EGFR TKI treatment was established in clinical trials. However, a treatment-emergent mutation of T790M (T) was identified as a major source of drug resistance. Irreversible 2nd and 3rd generation EGFR TKIs were shown effective. Mutant-specific inhibition by 3rd generation EGFR TKIs reduced adverse events such as skin toxicities. The emergence of a missense mutation at C797 (C), to which irreversible TKIs covalently bind, limited their efficacy. Patients harboring treatment-emergent C mutations are left with few therapeutic options. Despite anecdotal reports of efficacy from 1st generation TKIs, these complex molecular variants involving C797 are an increasing clinical concern. To prevent the emergence of drug-resistant subclones, a broad-spectrum EGFR TKI against both treatment-emergent and drug-naïve mutants is required. Such a 4th generation EGFR TKI must also enable monotherapy, allowing precise dose adjustment in case of toxicity. Method: Derived from BBT-176 which is under clinical evaluation (NCT04820023), we synthesized BBT-207 and other related molecules. Using Promega ADP-Glo™ kinase assay, we tested compounds against wild-type (WT) and mutated EGFR proteins. Ba/F3 cells harboring WT and mutated EGFR genes were created and cell viability was measured by CellTiter-Glo® and SpectraMax iD3®. In vivo anti-tumor activity was evaluated in Ba/F3 cell-derived xenograft models and an Osimertinib-resistant patient-derived xenograft model. Single dose pharmacokinetic (PK) study was performed in animals. Results: BBT-207 showed IC50 values < 10 nM against EGFR triple mutants (DTC and LTC) and comparable IC50 values against double mutants (DC and LC), while Osimertinib was ineffective in both groups. BBT-207 was also as active as Gefitinib to single mutants (D and L). Double mutants containing T790M (DT and LT) were inhibited effectively by BBT-207 and Osimertinib at similar concentrations, while not by Gefitinib. In in vivo models to which Osimertinib was inactive (LC and DTC), significant tumor growth inhibition was observed from BBT-207 alone, which was enhanced by the addition of Osimertinib. PK studies in mouse, rat, dog and monkey were consistent with high exposure and sustained drug concentrations above the IC50 values, with evidence of penetration into the central nervous system. Conclusion: BBT-207 is a reversible, mutant-specific, broad-spectrum TKI, active to clinically observed mutations of EGFR and is expected to be compatible with monotherapy of QD schedule in humans. BBT-207 is well-positioned to augment the treatment of EGFR mutated NSCLC, either for acquired drug resistance or in earlier line. Citation Format: Taiguang Jimmy Jin, Sang-Uk Kang, Chulwon Kim, Jehrod Brenneman, Mihee Song, Pavel Printsev, Bo-Bae Seo, Yong-Hee Lee, Sang-Yoon Lee. BBT-207, a novel, 4th generation, epidermal growth factor receptor (EGFR) tyrosine kinase inhibitor (TKI) with broad-spectrum activity to both treatment-emergent and drug-naïve mutants for the treatment of NSCLC [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 3346.

Abstract CT559: Capmatinib plus osimertinib vs platinum-pemetrexed doublet chemotherapy as second-line therapy in patients with stage IIIB/IIIC or IV EGFR-mutant, T790M-negative NSCLC harboring MET amplification

Abstract Background: MET amplification can arise as a bypass resistance mechanism to EGFR tyrosine kinase inhibitors (TKIs) and occurs in ~5-26% of EGFR TKI resistant EGFR-mutant non-small cell lung cancer (NSCLC). These patients (pts) have limited treatment options, particularly in the EGFR T790M negative (T790M−) setting. Capmatinib, a MET inhibitor, is approved in more than 10 countries for the treatment of metastatic MET exon 14 skipping NSCLC. In preliminary studies, capmatinib plus EGFR TKIs showed antitumor activity in the post-EGFR TKI, EGFR-mutant NSCLC setting. GEOMETRY-E (NCT04816214) is a randomized, controlled, open-label, multicenter, phase 3 study evaluating the efficacy and safety of capmatinib + osimertinib vs platinum-pemetrexed doublet chemotherapy as second line treatment in the advanced NSCLC setting. Methods: This ongoing study began enrollment in September 2021 and is recruiting adult pts with stage IIIB/IIIC or IV EGFR-mutant, T790M−, MET-amplified NSCLC who had progressed on either 1st/2nd generation EGFR TKIs, osimertinib or other 3rd generation EGFR TKIs. Pts with neurologically unstable, symptomatic CNS metastases or those requiring increasing doses of steroids ≤2 weeks prior to study entry to manage CNS symptoms are ineligible. This is a 2-part study where Part 1 (initial run-in, ~10 pts) will confirm the recommended dose for the randomized Part 2 and evaluate the safety and tolerability of capmatinib + osimertinib. In Part 1, pts will receive oral capmatinib 400 mg twice daily + osimertinib 80 mg once daily in 21-day cycles. Part 2 will evaluate the efficacy and safety of capmatinib + osimertinib vs platinum (cisplatin/carboplatin)-pemetrexed. Part 2 will enroll ~225 pts, in 2:1 randomization, stratified by the presence of brain metastases (yes/no) and prior treatment with 3rd generation EGFR TKIs (yes/no). In Part 1, the primary endpoint is the incidence of dose limiting toxicities during the first 21 days of treatment. Secondary endpoints include safety; tolerability; pharmacokinetics (PK); investigator-assessed overall response rate (ORR), duration of response (DOR), time to response (TTR), disease control rate (DCR) and progression-free survival (PFS) per the Response Evaluation Criteria in Solid Tumors version 1.1 (RECIST 1.1). In Part 2, the primary endpoint is blinded independent review committee (BIRC)-assessed PFS per RECIST 1.1. The key secondary endpoints are ORR by BIRC per RECIST 1.1 and overall intracranial response rate (OiRR) by BIRC per Response Assessment in Neuro-Oncology Brain Metastases (RANO-BM). Other secondary endpoints include DOR, TTR and DCR by BIRC; investigator-assessed PFS after next line of treatment; PK; safety; overall survival; patient-reported outcomes; intracranial DCR, duration of and time to intracranial response by BIRC per RANO-BM. Citation Format: Yi-Long Wu, Ji-Youn Han, Terufumi Kato, Fabrice Barlesi, Edward B. Garon, Federico Cappuzzo, Yuji Shibata, Nathalie Smith, Sadhvi Khanna, Riccardo Belli, Alejandro Yovine, Daniel Tan. Capmatinib plus osimertinib vs platinum-pemetrexed doublet chemotherapy as second-line therapy in patients with stage IIIB/IIIC or IV EGFR-mutant, T790M-negative NSCLC harboring MET amplification [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr CT559.

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

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

Abstract 1827: CD70 is a novel therapeutic target for EGFR mutant NSCLC with acquired, EMT-associated EGFR TKI resistance

Abstract Approximately 15% of all patients with non-small cell lung cancer (NSCLC) and nearly 35% of Asian patients with NSCLC harbor activating mutations within the epidermal growth factor receptor (EGFR). Although these patients are initially highly sensitive to first or second generation EGFR tyrosine kinase inhibitors (TKIs) including erlotinib or third-generation inhibitors including osimertinib, EGFR TKI-refractory disease inevitably emerges. While therapeutic strategies to target resistant disease that emerges though secondary EGFR mutations or MET amplification have been developed, there remains a void of therapeutic options for patients where resistance occurs through EGFR-independent mechanism such as epithelial to mesenchymal transition (EMT) or transformation to small cell lung cancer (SCLC). To identify cell surface proteins that could be targeted by antibody-based or adoptive cell therapy approaches we interrogated RNAseq data from EGFR mutant NSCLC cell lines (HCC827 and HCC4006) and their associated EGFR TKI resistant variants previously shown to have developed resistance through EMT and filtered gene expression data to include only genes which transcribed proteins localized to the cell surface. We identified CD70 as a being highly upregulated in EGFR TKI resistant cells (p = 7.2e-42). Given that CD70 expression is highly restricted and only transiently expressed on immune cells, CD70 was selected as a top candidate cell surface protein for targeting studies. Western blotting and flow cytometry analysis confirmed CD70 protein levels to be highly upregulated in EGFR TKI resistant cells that had undergone EMT but not in cells harboring secondary EGFR mutations or MET amplifications. We also observed CD70 upregulation in osimertinib-treated drug tolerant persister cells, indicating that CD70 upregulation is an early event in the evolution of TKI resistance. Moreover, patient-derived models of acquired EGFR TKI resistance also exhibited CD70 positivity. Our data also indicated that in EGFR mutant NSCLC cells, CD70 could be upregulated through decreased CD70 promoter methylation as well as by the EMT regulators, transforming growth factor-β (TGF-β) and ZEB1, both of which were upregulated in TKI resistant cells. In EGFR TKI resistant cells, CD70 knockdown impaired cell viability and invasiveness, and stimulation of CD70 using the exogenous binding partner CD27 resulted in activation of AKT and MAPK, pathways known to be re-activated with acquired TKI resistance. CD70-targeting approaches including anti-CD70 antibody drug conjugates (ADCs) and CD70-targeting CAR T cell and CAR NK cells showed promising in vitro and in vivo activity against CD70 positive tumor cells and in osimertinib drug-tolerant persister cells. These results identify CD70 as a novel therapeutic target for EGFR mutant tumors with acquired EGFR TKI resistance that merits further investigation in the clinic. Citation Format: Monique B. Nilsson, Yan Yang, Sonia Patel, Simon Heeke, Xiuning Le, Thiru Aruguman, Jacqulyne Robichaux, Xiaoxing Yu, Alissa Poteete, Xiaoyang Ren, Lixia Diao, Li Shen, Qi Wang, Fahao Zhang, Leticia Campos Clemente, Luisa Solis Soto, Chunhua Shi, Hai Tran, Jason Bock, Jing Wang, Ignacio I. Wistuba, John D. Minna, John V. Heymach. CD70 is a novel therapeutic target for EGFR mutant NSCLC with acquired, EMT-associated EGFR TKI resistance [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 1827.

Abstract 417: Identification of next-generation EGFR degraders to treat non-small cell lung cancer (NSCLC) patients

Abstract Although EGFR-targeted tyrosine kinase inhibitors (TKIs) developed over a couple of decades have made great progress in the treatment of EGFR-mutant driven NSCLC, patients are at great risk to their lives due to drug resistance caused by constantly emerging EGFR mutations. Targeted protein degraders (TPDs), also known as heterobifunctional protein degraders or PROteolysis TArgeting Chimeras (PROTACs), have drawn great attention as a new modality to overcome drug resistance by achieving selective degradation of disease-causing proteins, like an EGFR mutant protein, which are required for the survival and proliferation of various malignant tumor cells. Therefore, we have developed a series of EGFR mutant degraders using BBT-176, a 4th generation EGFR TKI developed by Bridge BioTherapeutics, and novel EGFR inhibitors as warheads which are expected not only to treat various EGFR mutated NSCLC including C797S but also to delay drug resistant-mechanisms by further mutations in the EGFR TKI target site. We synthesized a set of heterobifunctional degraders applying Cyrus BiFx Degrader (CBD) library platform containing different types of linkers and E3 ligase binders. DC50 (half-maximal degradation concentrations) values of the EGFR degraders were obtained in multiple human EGFR mutant NSCLC cell lines, where C-2051, C-2482, and C-4383 showed excellent EGFR degradation potency (DC50 = 7-25 nM, Dmax at 100 nM = 80-97%) with high selectivity against WT EGFR. Among those compounds, C-4383 was potent in cell viability assays with EGFR mutant HCC827 (Del19) and NCI-H1975 (L858R, T790M) cell lines showing a range of GI50 values from 77 to 81 nM at 72 h of compound exposure. By contrast, the compound was much less potent in A549 cells harboring wild-type EGFR (GI50 value at 72 h of treatment, 4.2 μM). We also performed proteomic analysis of C-4383 in H1975 cells resulting that EGFR was the most degraded protein with no off-target events at 100 nM (Dmax dose). A PK study of C-4383 in rats showed good exposure with moderate CL when administered intravenously (CL = 8.51 mL/min/kg, AUC = 5911 ng•h/mL). In summary, we identified heterobifunctional degraders using a 4th generation EGFR inhibitor, BBT-176, that are active in EGFR mutant NSCLC cells harboring single or C797S-containing multiple mutations. We are currently making our efforts on the improvement of physicochemical properties of EGFR mutant targeted heterobifunctional compounds. Citation Format: Dong Hyuk Ki, Joonwoo Nam, Eunjung Kim, Hunmi Choi, Chulwon Kim, Jiyeon Kim, Jimmy Jin, Sang-Uk Kang, Wooseok Han. Identification of next-generation EGFR degraders to treat non-small cell lung cancer (NSCLC) patients [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 417.

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

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

Efficacy and safety of ASK120067 (limertinib) in patients with locally advanced or metastatic EGFR T790M-mutated non–small cell lung cancer: A multicenter, single-arm, phase IIb study.

9106 Background: ASK120067 (Limertinib) is a newly developed third-generation epidermal growth factor receptor (EGFR) tyrosine kinase inhibitor (TKI) targeting both sensitizing EGFR and EGFR T790M mutations. This study aimed to evaluate the efficacy and safety of ASK120067 in patients with locally advanced or metastatic EGFR T790M mutated non-small cell lung cancer (NSCLC). Methods: This study was a single-arm, open-label, phase 2b study conducted at 62 hospitals across China. Patients with locally advanced or metastatic NSCLC with centrally confirmed EGFR T790M mutations in tumor tissue or blood plasma who progressed after first or second generation EGFR TKIs or with primary EGFR T790M mutations were enrolled. Patients received ASK120067 160mg orally twice daily, until disease progression, or unacceptable toxicity. The primary endpoint was objective response rate (ORR) assessed by Independent Review Committee (IRC) per RECIST1.1. Secondary endpoints included disease control rate (DCR), progression-free survival (PFS), duration of response (DOR), overall survival (OS), and safety. Safety was assessed according to CTCAE 4.03. Results: Between June 24th, 2019 and Feb 25th, 2021 301 patients were enrolled and received ASK120067 treatment. All patients entered the full analysis set (FAS) and safety set (SS). A total of 99 (32.9%) patients had central nervous system (CNS) metastases at baseline. By the data cutoff date on Sep 9th, 2021, 76 (25.2%) remained on treatment. The median follow-up time was10.4 (range 0.3-26.3) months. Based on FAS, the IRC-assessed ORR was 68.8% (95%CI 63.2%-74.0%) and DCR was 92.4% (95%CI 88.8%-95.1%). The median PFS was 11.0 (95%CI 9.7-12.4) months, median DOR was 11.1 (95%CI 9.6-13.8) months, and median OS was not reached (NR) (95%CI 19.7 months-NR). Objective responses were achieved across all pre-specified subgroups. For 99 patients with CNS metastases, the ORR was 64.6% (95%CI 54.4%-74.0%), median PFS was 9.7 (95%CI 5.9-11.6) months, and median DOR was 9.6 (95%CI 8.1-15.2) months. For 41 patients who had evaluable CNS lesion, the confirmed CNS-ORR was 56.1% (95%CI, 39.7%-71.5%) and median CNS-PFS was 10.6 (95%CI 5.6-NE) months. In SS, 289 (96.0%) patients experienced at least one adverse drug reaction (ADR), with the most common being diarrhea (81.7%), anemia (32.6%), rash (29.9%) and appetite decrease (28.2%). Grade ≥3 ADRs occurred in 104 (34.6%) patients, and the most common included diarrhea (13.0%), hypokalemia (4.3%), anemia (4.0%) and rash (3.3%). ADRs leading to dose interruption and dose discontinuation occurred 24.6% and 2% of patients, respectively. No ADR leading to death occurred. Conclusions: ASK120067 demonstrated promising efficacy and an acceptable safety profile for the treatment of patients with locally advanced or metastatic EGFR T790M mutated NSCLC. Clinical trial information: NCT03502850.

Capmatinib plus osimertinib versus platinum-pemetrexed doublet chemotherapy as second-line therapy in patients with stage IIIb/IIIc or IV EGFR-mutant, T790M-negative NSCLC harboring MET amplification.

TPS9153 Background: MET amplification can arise as a bypass resistance mechanism to EGFR tyrosine kinase inhibitors (TKIs) and occurs in ̃5-26% of EGFR TKI resistant EGFR-mutant non-small cell lung cancer (NSCLC). These patients (pts) have limited treatment options, particularly in the EGFR T790M negative (T790M−) setting. Capmatinib, a MET inhibitor, is approved in about ten countries for the treatment of metastatic MET exon 14 skipping NSCLC. In preliminary studies, capmatinib plus EGFR TKIs showed antitumor activity in the post-EGFR TKI, EGFR-mutant NSCLC setting. GEOMETRY-E (NCT04816214) is a randomized, controlled, open-label, multicenter, phase 3 study evaluating the efficacy and safety of capmatinib + osimertinib vs platinum-pemetrexed doublet chemotherapy as second line treatment for advanced NSCLC. Methods: This ongoing study began enrollment in September 2021 and is recruiting adult pts with stage IIIB/IIIC or IV EGFR-mutant, T790M−, MET-amplified NSCLC who had progressed on either 1st/2nd generation EGFR TKIs, osimertinib or other 3rd generation EGFR TKIs. Pts with neurologically unstable, symptomatic CNS metastases or those requiring increasing doses of steroids ≤2 weeks prior to study entry to manage CNS symptoms are ineligible. This is a 2-part study where Part 1 (initial run-in,̃10 pts) will confirm the recommended dose for the randomized Part 2 and evaluate the safety and tolerability of capmatinib + osimertinib. In Part 1, pts will receive oral capmatinib 400 mg twice daily + osimertinib 80 mg once daily in 21-day cycles. Part 2 will evaluate the efficacy and safety of capmatinib + osimertinib vs platinum (cisplatin/carboplatin)-pemetrexed. Part 2 will enroll ̃225 pts, in 2:1 randomization, stratified by the presence of brain metastases (yes/no) and prior treatment with 3rd generation EGFR TKIs (yes/no). In Part 1, the primary endpoint is the incidence of dose limiting toxicities during the first 21 days of treatment. Secondary endpoints include safety; tolerability; pharmacokinetics (PK); investigator-assessed overall response rate (ORR), duration of response (DOR), time to response (TTR), disease control rate (DCR) and progression-free survival (PFS) per the Response Evaluation Criteria in Solid Tumors version 1.1 (RECIST 1.1). In Part 2, the primary endpoint is blinded independent review committee (BIRC)-assessed PFS per RECIST 1.1. The key secondary endpoints are ORR by BIRC per RECIST 1.1 and overall intracranial response rate (OiRR) by BIRC per Response Assessment in Neuro-Oncology Brain Metastases (RANO-BM). Other secondary endpoints include DOR, TTR and DCR by BIRC; investigator-assessed PFS after next line of treatment; PK; safety; overall survival; patient-reported outcomes; intracranial DCR, duration of and time to intracranial response by BIRC per RANO-BM. Clinical trial information: NCT04816214.

EGFR mutations in lung carcinomas: Mutation profile and survival analysis.

e20518 Background: Epidermal growth factor receptor (EGFR) mutation have been demonstrated to be both predictive and prognostic for patients with metastatic lung cancer. The administration of EGFR tyrosine kinase inhibitors (TKIs) has improved survival in this group of patients. Several generations of EGFR TKIs are currently available. The EGFR mutations have been divided into common and rare. The common mutations include Exon 19 deletion and Exon 21 L858R mutations and rest are grouped as rare. The presence of visceral metastasis in the brain and liver are usually portends a poor prognosis. Methods: We conducted a retrospective analysis of lung cancer patients who attended our hospital outpatient department from 2017 to 2021. The prevalence, demographics and clinical profile of EGFR common and rare mutations were studied using descriptive statistics. Survival of EGFR mutated patients was plotted using Kaplan Meier plots. SPSS was used for statistical analysis. Results: The prevalence of EGFR mutation among metastatic lung cancer was 14.10% (161/1148). The median age of the group was 60 years (23- 104 years). Smokers with EGFR mutations were 11.8% (n = 19). Male to Female ratios was 76:85 (47.2% and 52.8%). Three patients with squamous cell carcinoma exhibited EGFR mutation. Most common EGFR TKI used was Gefitnib. Osimertinib was used in 13 patients (1.4%). The percentage of common mutations were 85.75% (N = 132) and rare mutations were 14.3% (n = 22). The type of mutations could not be identified in 10 patients. The percentage of patients with exon 19 deletion were 63% (n = 97) and L858R were 24.7% (n = 38). Visceral metastasis (brain and liver) was seen in 47 patients (n = 29.2%). Brain progression was seen in 32 patients (n = 19.9%). The survival of patients with EGFR exon 19 deletion and L858R mutation was 16.36 + 8.97 months and 15.97+ 10.93 months, Survival among patients with common mutation was 16.20 + 9.57 months and among rare mutation was 13.43 + 12.19 months. Median Survival period of patients with visceral metastasis was 12 months (0 to 38 months). Conclusions: In our retrospective study, there was no significant difference between survival among common and rare EGFR mutations.

An exploration of the clinical progression models of osimertinib in the treatment of advanced EGFR-mutant non-small cell lung cancer.

BackgroundClassifying the progression pattern had been proved to be momentous for predicting efficacy and guiding treatment in the 1st/2nd generation epidermal growth factor receptor tyrosine kinase inhibitors (EGFR-TKIs), while lack evidence in the 3rd generation EGFR-TKIs. This study aimed to classify tumor progression of osimertinib in EGFR+ advanced non-small cell lung cancer (NSCLC), exploring the characteristics and the clinical significance of each progression pattern.MethodsAfter screening 1,125 lung cancer patients, 168 EGFR T790M+ advanced patients using osimertinib were enrolled and divided into two groups and five clinical progression models according to the time course of the tumor progression. The prognosis and characteristics, such as gender, age, metastases, of each model were analyzed and compared by Kaplan-Meier method, t-test, and linear regression.ResultsComplete follow-up data were available for 117 of the 168 patients. Progressive disease (PD) occurred in 89 patients at an average onset of 6.59 months since using osimertinib, with 79.78% of patients experiencing enlargement of some preexisting lesions before PD. Among the five progression models, the ‘Rapid Enlargement’ (10.11%) model, the ‘Rapid New Lesion’ model (10.11%), the ‘Delayed Enlargement’ model (29.21%), the ‘Delayed New Lesion’ model (15.73%), and the ‘Non-targeted Enlargement’ model (34.83%), the ‘Non-targeted Enlargement’ model had the worst prognosis, with a median progression-free survival (mPFS) of 7.1 months (P=0.046). The mPFS of other models was similar, with the largest difference in the time interval between the beginning of osimertinib treatment to the first appearance of target lesion enlargement (Tm-e). Smoking history (P=0.046) and the location of the initial (P=0.048), enlarged (P=0.003), and progressive lesions (P=0.002) affected the progression models, while gender, age, and treatment lines had no effect. The Tm-e was related to the overall disease control time with a correlation coefficient of 0.667 (P=0.000). The appearance of a malignant pleural effusion had an impact on progression.ConclusionsWe tried to create a classification system for describing the failure of the third-generation EGFR-TKI osimertinib including two groups, subdivided into five progression models based on the time course of tumor lesion changes. The system might be conducive to predict the prognosis and be potential to assist in selecting subsequent treatment strategies.

48P Efficacy of osimertinib (osi) on (prevention of) bone metastases (mets) and skeletal related events (SREs) in patients (pts) with epidermal growth factor receptor mutated (EGFRm+) non-small cell lung cancer (NSCLC)

The incidence of bone mets in NSCLC is high and seems especially high in EGFRm+ NSCLC. Up to half of the pts with bone mets develop SREs while treated with 1st/2nd generation EGFR-tyrosine kinase inhibitors (TKI). Bone mets and SREs are associated with decreased overall survival (OS) and quality of life. Osi is current preferred first-line treatment for EGFRm+ NSCLC. We evaluated osi efficacy regarding bone mets and SREs.

Efficacy and safety of adjuvant EGFR-TKIs for resected non-small cell lung cancer: a systematic review and meta-analysis based on randomized control trials

BackgroundPostoperative adjuvant cisplatin-based chemotherapy had been the standard care in patients with completely resected high-risk stage IB to IIIA non-small cell lung cancer (NSCLC) for decades. However, the survival benefits were far from satisfactory in clinical practice. Thus, this meta-analysis was performed to compare the efficacy and safety of adjuvant epidermal growth factor receptor tyrosine kinase inhibitors (EGFR-TKIs) in patients with resected NSCLC based on updated literature and research.MethodsA systematic literature search based on random control trials (RCTs) was conducted with keywords on PubMed, Embase and the Cochrane library databases. All articles compared EGFR-TKIs to placebo or chemotherapy as adjuvant therapies for early-stage resected NSCLC. A meta-analysis was performed to generate combined hazard ratio (HR) with 95% confidence intervals (CI) for disease-free survival (DFS), overall survival (OS), and risk ratio (RR) with 95% CI for disease recurrence and adverse events (AEs). The Stata statistical software (version 14.0) was used to synthesis the data.ResultsA total of 9 RCTs comprising 3098 patients were included. Adjuvant EGFR-TKIs could significantly prolong DFS in patient with resected NSCLC harboring epidermal growth factor receptor (EGFR) mutations (HR 0.46, 95% CI 0.29–0.72), but had no impact on OS (HR 0.87, 95% CI 0.69–1.11). The subgroup analyses indicated that adjuvant EGFR-TKIs were superior in regard to DFS in most subgroups, including varied smoking status, EGFR mutations type, gender, age, Eastern Cooperative Oncology Group performance status and adenocarcinoma. Osimertinib resulted in decreased brain recurrence than first generation of EGFR-TKIs (RR 0.12, 95% CI 0.04–0.34 vs. RR 1.07, 95% CI 0.64–1.78, respectively). The AEs were generally manageable and tolerable. The incidence of high-grade (≥ 3) AEs including diarrhea (RR 5.68, 95% CI 2.94–10.98) and rash (RR 27.74, 95% CI 11.43–67.30) increased after adjuvant EGFR-TKIs treatment.ConclusionsAdjuvant EGFR-TKIs therapy could significantly prolong DFS in patients with completely resected early-stage EGFR mutation-positive NSCLC, but had no impact on OS. Adjuvant EGFR-TKIs could be an important treatment option in patients with resected early-stage EGFR-mutant NSCLC.

ORIENT-31 as the Sakigake "Charging Samurai" Born of IMpower150 but Will MARIPOSA-2 IMPRESS in the "Meiji Modernization" of Post-3G EGFR TKI Progression?

Tyrosine kinase inhibitors (TKIs) have become the preferred first line therapy for those patients with non-small cell lung cancer (NSCLC) harboring epidermal growth factor receptor (EGFR) mutations. Given superior progression free survival (PFS) and overall survival (OS) when compared to earlier generations, third generation EGFR TKIs have become the first choice therapy in many parts of the world. Even though multiple strategies are in development to target both “on-target” and “off-target” resistance, the continuation of EGFR TKIs at the time of progression remains a controversial topic. This commentary focuses on both the ”classic” clinical trials of IMpower150 and IMPRESS and compares them to the recently reported ORIENT-31 and ongoing MARIPOSA-2 to discuss the future therapeutic strategies in the setting of progression post-third generation EGFR TKIs.

The Multi-Omics Analysis of Key Genes Regulating EGFR-TKI Resistance, Immune Infiltration, SCLC Transformation in EGFR-Mutant NSCLC.

BackgroundLung cancer is a high-risk malignancy worldwide. The harboring of epidermal growth factor receptor (EGFR) mutations in non-small cell lung cancer (NSCLC) makes EGFR-tyrosine kinase inhibitor (EGFR-TKI) an attractive therapeutic option. However, patients usually suffer the primary and secondary resistance to EGFR-TKI. And the molecular alteration is still not fully clear and needs further study.MethodsThe GEO database was utilized to find the differentially expressed genes (DEGs) in NSCLC profiles resistant to the 1st or 2nd generation EGFR-TKI. We analyzed the expression and pathway enrichment of hub genes, and the prognosis of EGFR mutant/wild-type lung adenocarcinoma (LUAD). Moreover, small cell lung cancer (SCLC) and TKI-resistant profiles were used to find common DEGs, and construct miRNA regulatory network. Analysis was performed of hub genes' related immune infiltration, drug sensitivity, and methylation. Further, we analyzed hub gene expression in EGFR-mutant LUAD and paracancerous tissue by qRT-PCR.ResultsA total of 107 DEGs were found related to TKI resistance. Eleven hub genes were obtained after visualization, of which 5 hub genes were co-expressed in SCLC with common miRNAs. Lower expression of SPP1 (hub gene) was associated with better survival in NSCLC. The immune infiltration analysis showed more CD4+ T cells in the resistant group with high expression of SPP1. SPP1 and CD44 promoters’ methylations were independent prognostic factors of LUAD. And the expression level of SPP1 related to the sensitivity of EGFR-TKIs in multiple cancer cell lines. qRT-PCR validated the higher expression of SPP1 in EGFR-mutant LUAD than in normal tissue.ConclusionOur study suggested that the upregulation of SPP1 might induce resistance to the 1st and 2nd generation EGFR-TKI, and influence tumor immune infiltration, resulting in poor survival. ZEB1, SPP1, MUC1, CD44, and ESRP1 might be molecular drivers of SCLC transformation of TKI resistance.