3rd Generation EGFR Tyrosine Kinase Inhibitors Research Articles

Amivantamab plus lazertinib in atypical EGFR-mutated advanced non-small cell lung cancer (NSCLC): Results from CHRYSALIS-2.

8516 Background: Afatinib is the only EGFR tyrosine kinase inhibitor (TKI) approved to treat patients (pts) with EGFR-mutated advanced NSCLC harboring atypical mutations (eg, S768I, L861Q, G719X), excluding exon 20 insertion mutations (Ex20ins). In a retrospective analysis of 38 TKI-naïve pts, 27 had a response to afatinib, with a median duration of response (mDoR) of 11.1 months (mo) and median progression-free survival (mPFS) of 10.7 mo (Yang Lancet Oncol 2015;16(7):830-8). Amivantamab (ami) is an EGFR- MET bispecific antibody with immune-cell directing activity. Lazertinib (laz) is a CNS-penetrant, 3rd-generation EGFR TKI. This combination was evaluated among pts with atypical EGFR-mutated advanced NSCLC. Methods: Cohort C of the CHRYSALIS-2 study (NCT04077463) enrolled pts with atypical EGFR mutations, excluding Ex20ins, who were treatment-naïve or had ≤2 prior lines, which may have included a 1st/2nd-generation EGFR TKI. Pts with Ex19del or L858R co-mutations were excluded. Ami was intravenously administered at 1050 mg (1400 mg, ≥80 kg) weekly for the first 4 weeks and then biweekly. Laz was given orally at 240 mg daily. Response was assessed by the investigator per RECIST v1.1. Results: As of 4 Dec 2023, 105 pts received ami+laz, with a median follow-up of 13.8 mo (range, 0.1–30.2). The median age was 64 years, 50% were female, 68% Asian, 30% White, and 35% had CNS lesions at baseline. The most common mutations were G719X (54%), L861Q (24%), and S768I (22%). The ORR was 51% (95% CI, 41–61). In the treatment-naïve subset (n = 49), ORR was 55% (95% CI, 40–69), with mDoR not estimable (NE; 95% CI, 9.9 mo–NE) and mPFS of 19.5 mo (95% CI, 11.0–NE). Among responders, 78% (21/27) had DoR ≥6 mo. The ORR for pts harboring solitary mutations at G719 (n = 13), L861 (n = 8), and S768 (n = 2) was 54%, 63%, and 100%, respectively. The ORR for pts with compound atypical mutations (n = 17) was 41%, with DoR ≥6 mo for all 7 responders. Among pts treated with prior afatinib (n = 40), ORR was 45% (95% CI, 29–62), with mDoR of 8.9 mo (95% CI, 2.8–NE) and mPFS of 5.7 mo (95% CI, 4.2–10.7). Among the 18 responders, 56% had DoR ≥6 mo. The most common AEs were primarily EGFR- and MET-related toxicities, primarily grade 1-2. Discontinuations of both ami and laz due to treatment-related AEs occurred in 9% of pts. The incidence of VTE was 30% (31/105), with the majority of events, 71% (22/31), occurring in the first 4 mo of treatment. The vast majority of pts, 97% (30/31), were not on anticoagulation at time of first VTE. The rate of pneumonitis/interstitial lung disease was 6%. Biomarker analyses are ongoing; updated results will be presented at time of meeting. Conclusions: In the largest, single-cohort, prospective study of atypical EGFR-mutated advanced NSCLC, ami+laz demonstrated clinically meaningful and durable antitumor activity in pts who were treatment-naïve or had disease progression on afatinib. Clinical trial information: NCT04077463 .

Abstract 6972: Programmed death-ligand 1 (PD-L1) upregulates c-MET phosphorylation via protein tyrosine phosphatase and contributes to the development of MET amplification in epidermal growth factor receptor (EGFR) mutant non-small cell lung cancer

Abstract High expression of programmed death-ligand 1(PD-L1) is associated with poor survival outcomes in epidermal growth factor receptor (EGFR) mutation non-small cell lung cancer (NSCLC) patients receiving EGFR tyrosine kinase inhibitors (EGFR-TKIs). In this study we aimed to determine how increased PD-L1 affects the signal transduction of EGFR-mutant NSCLC cells. We first established PD-L1 overexpression EGFR mutant NSCLC cells, and discovered that PD-L1 overexpression cells had upregulated c-MET phosphorylation compared with parental cells using receptor tyrosine kinase array study. Subsequently, we demonstrated that knocking out PD-L1 (CD 274) in EGFR mutant NSCLC cells resulted in down-regulation of c-MET phosphorylation. Since protein tyrosine phosphatases (PTP) are known key regulators for c-MET phosphorylation and dephosphorylation, the activity of PTP was assessed. In PD-L1 overexpression EGFR mutant NSCLC cells, the PTP activity was decreased, whereas in PD-L1 knock-out cells, the PTP activity was increased. Additionally, the downregulation of c-MET phosphorylation in PD-L1 knock-out cells could be restored by adding PTP inhibitor (Na3VO4). The gene expression analysis showed that PTP expression was down-regulated in PD-L1 overexpression cells, indicating that PD-L1 upregulates c-MET phosphorylation by reducing PTP expression. We further established xenograft animal models using NSCLC cells with strong baseline c-MET phosphorylation to determine the effect of c-MET phosphorylation on osimertinib (a 3rd-generation EGFR-TKI) treatment. We found that tumor cells with strong c-MET phosphorylation were prone to develop MET amplification as acquired resistance under osimertinib, which could be overcome with combination of osimertinib and tepotinib, a c-MET inhibitor. Taken together, our results expand our understanding of PD-L1’s role beyond an immune checkpoint in EGFR mutant NSCLC. PD-L1-regulated MET alterations could be a crucial mechanism leading to poor treatment outcome of EGFR-TKIs in PD-L1 overexpression EGFR mutant NSCLC. Citation Format: Derek De-Rui Huang, Chia-Chi Hsu, Wei-Hsun Hsu, Bin-Chi Liao, James Chih-Hsin Yang. Programmed death-ligand 1 (PD-L1) upregulates c-MET phosphorylation via protein tyrosine phosphatase and contributes to the development of MET amplification in epidermal growth factor receptor (EGFR) mutant non-small cell 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 6972.

Risk factors for venous thromboembolism (VTE) among patients with EGFR-mutated advanced non-small cell lung cancer (NSCLC) receiving amivantamab plus lazertinib versus either agent alone.

9137 Background: Amivantamab (ami), an EGFR and cMET bispecific antibody with immune cell-directing activity, and lazertinib (laz), a CNS-penetrant 3rd-generation EGFR tyrosine kinase inhibitor have shown clinical activity in biomarker-selected patients (pts) with advanced NSCLC. Antitumor activity has been suggested to be improved when the agents are given in combination (Leighl Ann Oncol 2021;32:suppl_5, 1192MO). We examined the incidence of VTE, a common adverse event (AE) among pts with lung cancer, for those receiving ami monotherapy, laz monotherapy, and ami+laz to investigate if there is elevated risk and understand potential predisposing risk factors. Methods: CHRYSALIS (NCT02609776; ami monotherapy and ami+laz), CHRYSALIS-2 (NCT04077463; ami+laz), and LASER201 (NCT04075396; laz monotherapy) are ongoing open-label studies of locally advanced/metastatic NSCLC. Two descriptive, univariate risk analyses were performed, with the primary analysis including all treatment-emergent VTE events (grouped term) and a secondary analysis that excluded VTE events occurring after progression of disease (PD) or within 30 days prior to PD. Results: This analysis included 560 pts who received ami monotherapy, 536 ami+laz, and 252 laz monotherapy, predominantly in the TKI-relapsed setting. The incidence of VTE events of any grade was numerically higher in pts who received ami+laz (21%) than those who received ami (11%) or laz (11%) monotherapy. The median time to onset of the first VTE event was 84.5 days for ami, 79 days for ami+laz, and 170 days for laz. The majority (64%) of ami+laz pts had VTE events in the first 4 months. The most common VTE events by preferred term were pulmonary embolism and deep vein thrombosis. The incidence of grade ≥3 VTE events was comparable among pts receiving ami (5%), ami+laz (6%), and laz (6%), and there were no grade 5 VTE events for ami+laz. The overall incidence of serious VTE AEs was low (ami, 3%; ami+laz, 5%; laz, 4%). There were 6 discontinuations due to VTE, 1 (0.2%) ami, 2 (0.4%) for ami+laz, and 3 (1.2%) laz. In the primary analysis, age ≥60 years was a significant risk factor ( P< 0.05). In the secondary analysis, age ≥60 years, ECOG performance status of 1 (vs 0), and response to therapy (partial response or better) were significant risk factors ( P< 0.05). Conclusions: Lung cancer diagnosis is a known risk factor for VTE. In a review across clinical trials, single-arm cohort data suggest there is a numerically higher incidence of VTE for ami+laz compared with each monotherapy. Age ≥60 years, ECOG performance status, and response to treatment are potential risk factors. The relationship between response and VTE is emerging and may reflect possible immune or inflammatory-mediated mechanisms. Further efforts to understand VTE-associated risk factors in randomized clinical trials are ongoing. Clinical trial information: NCT02609776 , NCT04077463 , NCT04075396 .

PDL1-status predicts primary resistance of metastatic, EGFR-mutated non small cell lung cancers to EGFR tyrosine-kinase inhibitors

BackgroundEGFR tyrosine-kinase inhibitors (TKIs) are the reference treatment for metastatic, EGFR-mutated, non-small-cell lung cancers (EGFRm NSCLCs). However, 16–20% of those tumors progress early (3–6 months) and factors predicting that resistance are unknown. This study was undertaken to examine PDL1 status as such a factor. MethodsThis retrospective analysis included metastatic, EGFRm-NSCLC patients who received first-line 1st-, 2nd- or 3rd-generation EGFR TKIs with PDL1 expression determined in pretreatment biopsies. Kaplan–Meier estimations of probabilities of progression-free survival (PFS) and overall survival (OS) were compared with log-rank test, and logistic-regression analyses. ResultsPDL1 status of the 145 included patients was ≥1% (47%), 1–49% (33%) or ≥50% (14%). For PDL1-positive vs PDL1-negative patients, respectively, median PFS lasted 8 (95% CI: 6–12) vs 12 (95% CI: 11–17) months (p = 0.008), with 18% vs. 8% (NS) of NSCLCs progressing at 3 months, and 47% vs. 18% (HR 0.25 [95% CI 0.10–0.566], p<0.001) at 6 months. Multivariate analysis retained 1st- or 2nd-generation EGFR TKI, brain metastases and albuminemia <35 g/L at diagnosis as significantly associated with shorter PFS, but not PDL1 status, which was independently associated with progression at 6 months (HR 3.76 [1.23–12.63], p = 0.02). PDL1-negative and PDL1-positive patients’ OS lasted 27 (95% CI 24–39) and 22 (95% CI 19–41) months, respectively (NS). Multivariate analysis retained only brain metastases or albuminemia <35 g/L at diagnosis as being independently associated with OS. ConclusionPDL1 expression ≥1% seems to be associated with early progression during the first 6 months of first-line EGFR-TKI treatment of metastatic EGFRm NSCLCs, without impacting OS.

ASK120067 (limertinib) exerts pre-clinical anti-tumor activity by inhibiting EGFR exon20 insertion

Epidermal growth factor receptor (EGFR) tyrosine kinase inhibitors (TKIs) are classic strategies for the individualized treatment for patients with non-small cell lung cancer (NSCLC). However, EGFR exon20 insertion (EGFR 20ins) mutations, accounting for 6%–12% of all EGFR mutant cases in NSCLC, are generally resistant to the reversible EGFR TKIs (such as gefitinib and erlotinib), which makes them challenging drug-targets in lung cancer. In our previous study, we identified ASK120067 (limertinib) as a novel 3rd-generation EGFR TKI targeting EGFR T790M mutation with promising clinical activities. Here, we accessed the potency of ASK120067 on EGFR 20ins activation and evaluated its in vitro and in vivo anti-tumor activity against EGFR 20ins driven tumor models. We found that ASK120067 showed potent inhibitory activity on TKI-resistant EGFR 20ins kinase. In TKI-resistant EGFR 20ins-dependent BaF3 cells, it dose-dependently suppressed EGFR phosphorylation, impeded cell proliferation, and induced cell apoptosis with much superior efficacy to gefitinib and erlotinib. Moreover, oral administration of ASK120067 decreased the level of phospho-EGFR 20ins and caused significant tumor regression in EGFR 20ins BaF3 xenograft model. These results presented the pre-clinical anti-tumor efficacy of ASK120067 in EGFR 20ins models and highlighted the potential value of ASK120067 for the treatment of NSCLC patients harboring EGFR 20ins mutations.

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.

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.

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

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.

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.

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.

Overcoming acquired resistance to third-generation EGFR inhibitors by targeting activation of intrinsic apoptotic pathway through Mcl-1 inhibition, Bax activation, or both.

Treatment of EGFR-mutant non-small cell lung cancer (NSCLC) with mutation-selective third-generation EGFR-tyrosine kinase inhibitors (EGFR-TKIs) such as osimertinib has achieved remarkable success in the clinic. However, the immediate challenge is the emergence of acquired resistance, limiting the long-term remission of patients. This study suggests a novel strategy to overcome acquired resistance to osimertinib and other third-generation EGFR-TKIs through directly targeting the intrinsic apoptotic pathway. We found that osimertinib, when combined with Mcl-1 inhibition or Bax activation, synergistically decreased the survival of different osimertinib-resistant cell lines, enhanced the induction of intrinsic apoptosis, and inhibited the growth of osimertinib-resistant tumor in vivo. Interestingly, the triple-combination of osimertinib with Mcl-1 inhibition and Bax activation exhibited the most potent activity in decreasing the survival and inducing apoptosis of osimertinib-resistant cells and in suppressing the growth of osimertinib-resistant tumors. These effects were associated with increased activation of the intrinsic apoptotic pathway evidenced by augmented mitochondrial cytochrome C and Smac release. Hence, this study convincingly demonstrates a novel strategy for overcoming acquired resistance to osimertinib and other 3rd generation EGFR-TKIs by targeting activation of the intrinsic apoptotic pathway through Mcl-1 inhibition, Bax activation or both, warranting further clinical validation of this strategy.

CHRYSALIS-2: A phase 1/1b study of lazertinib as monotherapy and in combination with amivantamab in patients with EGFR-mutant NSCLC.

TPS9132 Background: Epidermal growth factor receptor (EGFR) tyrosine kinase inhibitors (TKIs) have improved clinical outcomes for patients with EGFR mutant (EGFRm) non-small cell lung cancer (NSCLC); however, patients will inevitably progress due to acquired resistance mutations. Lazertinib is a potent, brain-penetrant, 3rd-generation EGFR TKI with efficacy against activating EGFR and resistance T790M mutations. Amivantamab is an EGFR-MET bispecific antibody with immune cell-directing activity that targets activating EGFR and MET mutations. Synergistic inhibition of the EGFR by targeting the receptor’s extracellular domain with amivantamab and the kinase domain with lazertinib, may lead to more potent inhibition of the EGFR pathway and potentially delay resistance. In the ongoing CHRYSALIS phase 1 study (NCT02609776), preliminary antitumor activity has been demonstrated with the combination of lazertinib and amivantamab in patients with treatment-naïve and osimertinib-relapsed EGFRm NSCLC (Cho Ann Oncol 2020;31:S813). Methods: CHRYSALIS-2 is an ongoing phase 1/1b open-label study of lazertinib as monotherapy and in combination with amivantamab in patients with advanced EGFRm NSCLC (NCT04077463; https://clinicaltrials.gov/ct2/show/NCT04077463 ). Phase 1 of the study has confirmed the safety and tolerability of lazertinib monotherapy in Japanese patients. The objective of phase 1b is to characterize the preliminary efficacy of lazertinib in combination with amivantamab in subpopulations of patients with EGFRm NSCLC (Phase 1b Expansion Cohorts) at the recommended combination dose of 1050 mg (1400 mg, ≥80 kg) IV amivantamab dosed weekly in cycle 1 (28-day cycle), every other week thereafter, and 240 mg oral lazertinib QD. Global enrollment in Phase 1b Expansion Cohorts is currently ongoing. Expansion Cohort A is enrolling patients who have progressed on 1st or 2nd-line osimertinib followed by platinum chemotherapy; Expansion Cohort B is enrolling patients with EGFR exon 20 insertion (Exon20ins) mutation who have progressed on prior therapy; and Expansion Cohort C is enrolling patients with uncommon non-Exon20ins EGFR mutations (i.e., S768I, L861Q, G719X) who are treatment-naïve or received 1st or 2nd-generation EGFR TKI as last therapy. The primary endpoints of the study are frequency of dose-limiting toxicity for phase 1 and 1b combination cohorts, and overall response rate for phase 1b expansion cohorts. Key secondary endpoints include safety (adverse events), pharmacokinetics, duration of response, clinical benefit rate, progression-free survival, and overall survival. Safety assessments will include monitoring AEs, clinical laboratory tests, ophthalmologic examination, ECG, and ECHO/MUGA. Blood samples will be collected to access PK. Tumor response will be assessed every 6 weeks by the investigator using RECIST, v1.1. Clinical trial information: NCT04077463.

Acquired Resistance Mechanism of EGFR Kinase Domain Duplication to EGFR TKIs in Non-Small Cell Lung Cancer.

PurposeEpidermal growth factor receptor kinase domain duplication (EGFR-KDD) is a rare and poorly understood oncogenic mutation in non–small cell lung cancer (NSCLC). We aimed to investigate the acquired resistance mechanism of EGFR-KDD against EGFR-TKIs.Materials and MethodsWe identified EGFR-KDD in tumor tissue obtained from a patient with stage IV lung adenocarcinoma and established the patient-derived cell line SNU-4784. We also established several EGFR-KDD Ba/F3 cell lines: EGFR-KDD wild type (EGFR-KDDWT), EGFR-KDD domain 1 T790M (EGFR-KDDD1T), EGFR-KDD domain 2 T790M (EGFR-KDDD2T), and EGFR-KDD both domain T790M (EGFR-KDDBDT). We treated the cells with EGFR tyrosine kinase inhibitors (TKIs) and performed cell viability assays, immunoblot assays, and ENU (N-ethyl-N-nitrosourea) mutagenesis screening.ResultsIn cell viability assays, SNU-4784 cells and EGFR-KDDWT Ba/F3 cells were sensitive to 2nd generation and 3rd generation EGFR TKIs. In contrast, the T790M-positive EGFR-KDD Ba/F3 cell lines (EGFR-KDDT790M) were only sensitive to 3rd generation EGFR TKIs. In ENU mutagenesis screening, we identified the C797S mutation in kinase domain 2 of EGFR-KDDBDT Ba/F3 cells. Based on this finding, we established an EGFR-KDD domain 1 T790M/domain 2 cis-T790M+C797S (EGFR-KDDT/T+C) Ba/F3 model, which was resistant to EGFR TKIs and anti-EGFR monoclonal antibody combined with EGFR TKIs.ConclusionOur study reveals that the T790M mutation in EGFR-KDD confers resistance to 1st and 2nd generation EGFR TKIs, but is sensitive to 3rd generation EGFR TKIs. In addition, we identified that the C797S mutation in kinase domain 2 of EGFR-KDDT790M mediates a resistance mechanism against 3rd generation EGFR TKIs.

Efficacy of the CDK7 Inhibitor on EMT-Associated Resistance to 3rd Generation EGFR-TKIs in Non-Small Cell Lung Cancer Cell Lines.

Epithelial to mesenchymal transition (EMT) is associated with resistance during EGFR tyrosine kinase inhibitor (EGFR-TKI) therapy. Here, we investigated whether EMT is associated with acquired resistance to 3rd generation EGFR-TKIs, and we explored the effects of cyclin-dependent kinase 7 (CDK7) inhibitors on EMT-mediated EGFR-TKIs resistance in non-small cell lung cancer (NSCLC). We established 3rd generation EGFR-TKI resistant cell lines (H1975/WR and H1975/OR) via repeated exposure to WZ4002 and osimertinib. The two resistant cell lines showed phenotypic changes to a spindle-cell shape, had a reduction of epithelial marker proteins, an induction of vimentin expression, and enhanced cellular mobility. The EMT-related resistant cells had higher sensitivity to THZ1 than the parental cells, although THZ1 treatment did not inhibit EGFR activity. This phenomenon was also observed in TGF-β1 induced EMT cell lines. THZ1 treatment induced G2/M cell cycle arrest and apoptosis in all of the cell lines. In addition, THZ1 treatment led to drug-tolerant, EMT-related resistant cells, and these THZ1-tolerant cells partially recovered their sensitivity to 3rd generation EGFR-TKIs. Taken together, EMT was associated with acquired resistance to 3rd generation EGFR-TKIs, and CDK7 inhibitors could potentially be used as a therapeutic strategy to overcome EMT associated EGFR-TKI resistance in NSCLC.

Abstract 1867: Characterization of multiple driver alterations in acquired resistance to osimertinib in EGFR-mutated lung cancer: implementation of single cell approaches

Abstract Background Despite a primary benefit, resistance to the 3rd generation EGFR-Tyrosine Kinase Inhibitor (TKI) osimertinib invariably occurs. Several reports have recently highlighted the emergence of new oncogenic alterations as an actionable mechanism of resistance. However, the question of whether those alterations occur within a single tumor cell or in distinct tumor cell populations is still pending. Understanding those mechanisms at a cellular level is essential for a better comprehension of acquired resistance mechanisms and to identify new therapeutic opportunities. Methods This project studied tissues and patient derived cell lines from the ongoing prospective MATCH-R study (NCT0251782), in which patients with unresectable or metastatic cancer are included upon acquired resistance to targeted therapies or immunotherapy. Serial blood samples and tumor biopsies are collected at progression, for targeted NGS, WES and RNAseq, as well as PDX and patient-derived cell lines development. EGFR-mutated patients presenting a new driver alteration at osimertinib progression were identified. Single cell isolation and whole genome amplification were performed on corresponding frozen biopsies and derived cell lines. Cell lines were then exposed to specific inhibitors targeting the different pathways involved and functional analysis were performed to study the efficiency of combining different targeted therapies. Results Out of 466 patients included in MATCH-R study since June 2015, 110 patients presented EGFR-mutated adenocarcinoma. Among the 38 patients who experienced progression to 2nd line osimertinib, 5 patients were identified with a new oncogenic driver alteration, including STRN-ALK fusion (n=1), FGFR3-TACC3 fusion (n=1), BRAFV600E mutation (n=2), KIF-RET fusion (n=1). One patient progressing to 1st line osimertinib was identified with FGFR3-TACC3 fusion. All samples presented the persistence of EGFR activating mutation, i.e. EGFR exon 19 deletion (n=4) and exon 21 L858R mutation (n=2). After single cell isolation from tissue biopsies, PCR and targeted NGS allowed to highlight the co-existence of both drivers within single tumor cells for three patients. The remaining samples are still under investigation. Combination strategies with dual TKI are currently ongoing in order to restore sensitivity in cell lines (IC50 and Western Blots). Perspectives These data allow a better understanding of mechanisms underlying cell adaptation to EGFR-driven tumor inhibition. Combining targeted therapies represents a valuable therapeutic opportunity to overcome drug resistance in EGFR-mutated lung cancer. Updated results will be presented at the Meeting. Citation Format: Jeanne Chen, Floriane Braye, Francesco Facchinetti, Ludovic Lacroix, Jean-Yves Scoazec, Lambros Tselikas, David Planchard, Laura Mezquita, Anas Gazzah, Charles Naltet, Pernelle Lavaud, Aline Maillard, Stefan Michiels, Christophe Massard, Ken.A. Olaussen, Fabrice André, Gilles Vassal, Jean-Charles Soria, Benjamin Besse, Luc Friboulet. Characterization of multiple driver alterations in acquired resistance to osimertinib in EGFR-mutated lung cancer: implementation of single cell approaches [abstract]. In: Proceedings of the Annual Meeting of the American Association for Cancer Research 2020; 2020 Apr 27-28 and Jun 22-24. Philadelphia (PA): AACR; Cancer Res 2020;80(16 Suppl):Abstract nr 1867.

Identification and in silico structural insights of rare recurrent EGFR mutations as resistance mechanisms to osimertinib in EGFR-mutated lung cancer.

9531 Background: Inevitable progression on 3rd-generation EGFR-tyrosine kinase inhibitor (TKI) osimertinib of EGFR-mutated lung cancer patients represents a great challenge in clinic. Previous studies have revealed that one-third of the resistant mechanisms are due to acquired EGFR secondary mutations, mainly on C797, L718 and L792 residues. Our study aims to gain insights into novel mechanisms of acquired resistance to osimertinib. Methods: We performed genomic profiling on a total of 1,058 EGFR-mutated lung cancer patients with progressed disease on osimertinib, and a cohort of 1,803 patients who received only 1st-generation EGFR TKIs upon progression. Recurrent EGFR mutations with a significant enrichment in the osimertinib group were identified. We further established and applied molecular dynamic simulation-based computational model of the mutant EGFR protein to predict its sensitivity to osimertinib. Results: As expected, compared with 1st-TKIs alone group, EGFR mutations, including C797S/G (22.1% vs. 0.5%), L718Q/V (6.2% vs. 0.3%), L792F/H (4.4% vs. 0.3%), were significantly more enriched in the osimertinib cohort. Our computational model has also successfully predicted their sensitivities to osimertinib: WT (-35.19 kcal/mol) &gt; L792F (-34.10 kcal/mol) &gt; L718Q (-30.33kcal/mol) &gt; C797S (-28.02 kcal/mol), which are consistent with our previous in vitro validations. Importantly, a total of 14 low-frequency EGFR mutations were exclusively observed in the osimertinib group, seven of which, including EGFR G796S(n = 6), V802F(n = 3), T725M(n = 2), Q791L/H(n = 2), P794S/R(n = 2), were predicted to dramatically reduce the binding affinity of osimertinib to EGFR. Of note, analysis of the pretreatment samples of two patients supported that EGFR V802F and Q791L/H were acquired during osimertinib treatment. Interestingly, EGFR G796S was predicted to be sensitive to gefitinib, suggesting the possibility of administration of gefitinib in patients with acquired EGFR G796S to first-line osimertinib treatment. Further in vitro functional validations are currently ongoing. Conclusions: Our study represents the largest EGFR-mutated lung cancer cohort so far to investigate osimertinib resistance in a real-world setting, and has uncovered a list of recurrent low-frequency EGFR mutations that may confer acquired resistance to osimertinib. Our in silico structural model was proved to be powerful and robust in the prediction of osimertinib sensitivity of EGFR mutants.

A phase III, open-label, randomized study of atezolizumab in combination with carboplatin + paclitaxel + bevacizumab compared with pemetrexed + cisplatin or carboplatin with stage IV non-squamous non-small cell lung cancer (NSCLC) with activating EGFR mutation or ALK translocation (ATLAS Trial).

TPS9636 Background: In patients with activating EGFR mutations and ALK fusion, target specific tyrosine kinase inhibitor (TKI) showed significant survival improvement compared to the cytotoxic chemotherapy. However, the questions remain which combination strategy will be the best option for the patients who have failed from TKI. Especially, the role of an immune checkpoint inhibitor (ICI) in this population is still unclear. This study is designed and conducted based on the recent subgroup analyses from the IMpower 150 study which showed the positive clinical outcomes of atezolizumab combined with VEGF inhibitor and conventional cytotoxic chemotherapy in EGFR mutation and ALK translocation. Methods: This study is the phase III, open-label, multicenter study of atezolizumab in combination with bevacizumab + carboplatin + paclitaxel (ABCP, Arm A) compared with pemetrexed + cisplatin or carboplatin (Arm B). The study population will be randomized to either Arm A (n = 152) or Arm B (n = 72) based on two stratification factors, EGFR vs. ALK and presence of brain metastases. In Arm A, patients will be treated with 4 or 6 cycles of ABCP followed by maintenance atezolizumab and bevacizumab every three weeks. In Arm B, pemetrexed maintenance therapy will be applied every three weeks after 4 or 6 cycles of pemetrexed + cisplatin or carboplatin. As key inclusion criteria, the patients must be diagnosed with stage IV non-squamous non-small cell lung cancer with either activating EGFR mutation or ALK translocation. All the patients need to be cytotoxic chemotherapy naïve and must have experienced disease progression to treatment with at least one EGFR or ALK TKI. If the patients have T790M mutation after 1st or 2nd generation EGFR TKI, second line 3rd generation EGFR TKI treatment is mandatory. The number of T790M positive patients is restricted to under 30% of the entire study population. The primary endpoint is progression-free survival and the major secondary endpoints are overall survival, objective response rate and duration of response. A total of 228 subjects will be enrolled to detect a hazard ratio of 0.67. The first subject received treatment in Aug. 2019 and 19 patients receive the treatment. This study is opened in 3 sites and expected to be opened at 18 sites in South Korea. The time point for the primary analyses is Q3. 2022. Clinical trial information: NCT03991403 .

536TiP - INSIGHT 2: Tepotinib plus osimertinib in patients with EGFR-mutant NSCLC having acquired resistance to EGFR TKIs due to MET-amplification: A phase II trial in progress study

BackgroundMET amplification (METamp) is a resistance mechanism to EGFR tyrosine kinase inhibitors (TKIs) occurring via over activation of downstream signaling pathways such as PI3K and MAPK. METamp occurs in ≈10% of patients receiving erlotinib, gefitinib, afatinib, or icotinib, and is the most common resistance mechanism to osimertinib in phase III trials, occurring in ≈19% of patients. Tepotinib, an oral once daily potent and selective MET inhibitor, is associated with improved survival in combination with gefitinib in patients with EGFR-mutant MET-amplified NSCLC with EGFR TKI resistance compared with standard chemotherapy in the INSIGHT study (NCT01982955): investigator-reported progression free survival (PFS) was 21.2 vs 4.2 months (HR 0.13; 90% CI 0.04, 0.43) and overall survival, (OS) was 37.3 vs. 13.1 months (HR 0.08; 90% CI 0.01, 0.51). Trial designINSIGHT 2 (NCT03940703) is a global single-arm, open-label, phase II trial of tepotinib in patients with advanced (stage IIIB/IV) NSCLC with resistance to 1st–3rd generation EGFR TKIs driven by METamp. Eligibility criteria include patients aged ≥18 years with advanced EGFR-mutant NSCLC and known T790M status, having acquired resistance to EGFR TKIs, and are METamp positive by plasma ‘liquid’ biopsy, with an ECOG PS of 0 or 1 and normal organ function. Prior immunotherapy is permitted but prior MET pathway-targeted therapy is not. Tepotinib (500 mg orally once daily) in combination with osimertinib (80 mg once daily) will be administered until disease progression, unacceptable toxicity, or withdrawal of consent. An initial safety run-in will comprise 6 patients (endpoint; dose-limiting toxicities); anticipated full enrollment is 90 patients. The primary endpoint is objective response rate (ORR) by independent review committee (RECIST v1.1). Secondary objectives include investigator-assessed ORR, duration of response, disease control, PFS, OS, pharmacokinetics, health-related quality of life, tolerability, and safety (NCI-CTCAE v5.0). Recruitment is ongoing and approximately 80 study sites in 17 countries in Europe, Asia, and North America are expected to participate in this study. Clinical trial identificationNCT03940703. Legal entity responsible for the studyMerck Healthcare KGaA. FundingMerck Healthcare KGaA. DisclosureJ.C-H. Yang: Honoraria (self), Advisory / Consultancy: Boehringer Ingelheim; Honoraria (self), Advisory / Consultancy: Eli Lilly; Honoraria (self), Advisory / Consultancy: Bayer; Honoraria (self), Advisory / Consultancy: Roche/Genentech/Chugai; Honoraria (self), Advisory / Consultancy: MSD; Honoraria (self), Advisory / Consultancy: Merck Serono; Honoraria (self), Advisory / Consultancy: Pfizer; Honoraria (self), Advisory / Consultancy: Novartis; Honoraria (self), Advisory / Consultancy: Celgene; Honoraria (self), Advisory / Consultancy: Merrimack; Honoraria (self), Advisory / Consultancy: Yuhan Pharmaceuticals; Honoraria (self), Advisory / Consultancy: BMS; Honoraria (self), Advisory / Consultancy: Ono Pharmaceutical; Honoraria (self), Advisory / Consultancy: Daiichi Sankyo ; Honoraria (self), Advisory / Consultancy: AstraZeneca; Honoraria (self), Advisory / Consultancy: Takeda Oncology; Honoraria (self), Advisory / Consultancy: Blueprint Medicines; Honoraria (self), Advisory / Consultancy: Hansoh Pharmaceuticals. B. Ellers-Lenz: Full / Part-time employment: Merck Healthcare KGaA. J. Straub: Full / Part-time employment: Merck Healthcare KGaA. A. Johne: Full / Part-time employment: Merck Healthcare KGaA. Y-L. Wu: Honoraria (self), Advisory / Consultancy: AstraZeneca; Advisory / Consultancy, Research grant / Funding (institution): Boehringer Ingelheim; Advisory / Consultancy: Merck; Honoraria (self), Advisory / Consultancy, Research grant / Funding (institution): Roche; Honoraria (self): Eli Lilly; Honoraria (self): Pfizer; Honoraria (self): Pierre Fabre; Honoraria (self): Sanofi.

P2.14-57 Efficacy of 3rd Generation EGFR-TKIs After Failing First or Second Generation EGFR-TKIs in EGFR Mutation-Positive NSCLC (ROOT-EGFR)

Over the past decade, treatment of EGFR mutation –positive NSCLC has been revolutionized with the development of next generation EGFR TKIs. Four epidermal growth factor receptor (EGFR) tyrosine kinase inhibitors (TKIs), erlotinib, gefitinib, afatinib and osimertinib, are currently available in Korea. Recent trials have compared the available and emerging EGFR TKIs head to head. The highly anticipated findings of the phase III FLAURA trial showed a nearly doubling of PFS with frontline osimertinib, a third-generation TKI, versus erlotinib or gefitinib. The optimal sequence of EGFR TKIs is still controversial. And many countries 3rd generation EGFR TKI is not readily available. The purpose of this study is to analyze the efficacy in patients who received first-line gefitinib, erlotinib, or afatinib and followed by 3rd generation EGFR-TKIs. This non-interventional observational study through big data analysis will retrospectively collect de-identified patient data from clinical data warehouse (CDW) using a unique algorithm with Standard Query Language (SQL) called ROOT project. Over 10 years, 2,358 patients were diagnosed recurrent or metastatic non-small cell lung cancer and received 1st or 2nd generation EGFR TKIs at Samsung Medical Center. 72.9% (1720/2358) of EGFR mutation-positive NSCLC patients received 1st or 2nd generation EGFR-TKIs as first line palliative chemotherapy. In total population, 30.8% (727/2358) patients received 3rd generation EGFR TKIs. Among them, patients who received 3rd generation EGFR TKI after 1st or 2nd generation EGF TKIs showed better overall survival (45.0 months (95% CI, 41.8-48.2). Among 1720 patients who received 1st or 2nd generation EGFR-TKIs as first line palliative chemotherapy, 313 patients received 3rd generation EGFR-TKIs as 2nd line chemotherapy and 200 patients received as more than 3rd line chemotherapy. However, there was no difference of overall survival between them (44.0 months vs 47.0months, p-value=0.104). This study was meaningful as a study of what can be the best sequence in EGFR-TKI treatment. Updated and detail clinical and exploratory biomarker outcome will be presented at the meeting.