EGFR TKI Research Articles

Amivantamab plus lazertinib vs osimertinib in first-line EGFR-mutant advanced non-small cell lung cancer (NSCLC) with biomarkers of high-risk disease: A secondary analysis from the phase 3 MARIPOSA study.

8504 Background: Amivantamab (ami) is an EGFR-MET bispecific antibody with immune cell-directing activity. Lazertinib (laz) is a CNS-penetrant, 3rd-generation EGFR TKI. In MARIPOSA (NCT04487080), first-line ami+laz provided a statistically significant improvement in progression-free survival (PFS) vs osimertinib (osi) in patients (pts) with EGFR-mutant advanced NSCLC (HR, 0.70; P< 0.001), including in pts with a history of brain metastases (HR, 0.69; Cho Ann Oncol 2023;34:S1306, LBA14). Pts with TP53co-mutations, detectable circulating tumor DNA (ctDNA), and baseline brain or liver metastases have poor prognoses. We evaluated outcomes for pts in these high-risk subgroups from MARIPOSA. Methods: MARIPOSA enrolled pts with treatment-naïve, EGFR-mutant (Ex19del or L858R) advanced NSCLC. This analysis included pts randomized to ami+laz (n = 429) or osi (n = 429). Pathogenic alterations were analyzed by next-generation sequencing (NGS) of baseline blood ctDNA with Guardant360 CDx. Ex19del and L858R ctDNA in blood was analyzed at baseline and Cycle (C) 3 Day (D) 1 with Biodesix droplet digital PCR (ddPCR). Results: Baseline ctDNA for NGS analysis of pathogenic alterations was available for 636 pts (ami+laz, n = 320; osi, n = 316). Among pts with TP53 co-mutation, mPFS was 18.2 months (mo) for ami+laz vs 12.9 mo for osi (HR, 0.65; P= 0.003). Pts with TP53 wild-type had a trend favoring ami+laz for mPFS (HR, 0.75; P =0.11). In pts with ddPCR-detectable ctDNA at baseline, ami+laz significantly prolonged mPFS vs osi (20.3 vs 14.8 mo; HR, 0.68; P= 0.002). Further, ami+laz significantly improved mPFS vs osi in pts with ctDNA clearance at C3D1 (24.0 vs 16.5 mo; HR, 0.64; P= 0.004) and in pts who did not clear ctDNA (16.5 vs 9.1 mo; HR, 0.48; P= 0.014). For pts with liver metastases at baseline, ami+laz significantly prolonged mPFS vs osi (18.2 vs 11.0 mo; HR, 0.58; P= 0.017), which is consistent with the improved PFS for ami+laz vs osi in pts with a history of brain metastases. Conclusions: Ami+laz demonstrated significantly improved mPFS vs osi in pts with biomarkers of high-risk disease. Given these features can occur in up to 85% of pts, ami+laz represents an important new standard of care for treatment-naïve EGFR-mutant advanced NSCLC. Clinical trial information: NCT04487080 . [Table: see text]

Real-world study of lazertinib as second-line or greater treatment in advanced non-small cell lung cancer.

Lazertinib is an oral, third-generation EGFR-TKI, which specifically targets the EGFR T790M mutation along with activating mutations Ex19del and L858R. More real-world data are needed to evaluate its efficacy and safety in treating locally advanced and metastatic non-small cell lung cancer (NSCLC) following prior EGFR TKI treatment. This multicenter retrospective study was conducted at seven university hospitals affiliated to the Catholic Medical Center (CMC) in Korea. A clinical data warehouse (CDW) platform was used to access and extract information. A total of 48 patients were assessed. The majority were female (75%) and diagnosed with adenocarcinoma (95.8%). All patients had the EGFR mutation at diagnosis, 27 (56.3%) had the exon 19 deletion, 20 (41.7%) had the L858R mutation, and one (2.0%) had the exon 18 mutation. The median progression-free survival (PFS) was 15.4 months. At 6, 12, and 18 months, PFS rates were 79.1%, 53.6%, and 27.3%, respectively. When PFS was analyzed by prior TKI duration (<18 months vs. >18 months), significant differences were noted at the 6 and 9-month mark (p = 0.013 and p = 0.010, respectively). In multivariate analysis for PFS, only prior TKI duration and ECOG score showed statistical significance (p = 0.026 and p = 0.049, respectively). In the multivariate analysis for OS, ECOG score showed statistical significance (p = 0.006). Among 48 patients, 34 (70.8%) experienced adverse events (AEs) related to lazertinib. The most frequent AEs were skin reaction (29.8%), diarrhea (21.3%), and peripheral neuropathy (20.8%). The results suggest that lazertinib is effective in second or more line settings, with tolerable safety profile. More patient data are necessary to find possible prognostic markers associated with patient outcome.

The clinicopathological features and possible physiological mechanisms of only the EGFR-T790M primary mutation in patients with lung adenocarcinoma

BackgroundThe treatment of non-small cell lung cancer (NSCLC) patients can be complicated by the presence of the EGFR-T790M mutation. Although primary or secondary EGFR-T790M mutations have been extensively studied worldwide, there are few reports on the clinicopathological characteristics and physiological mechanisms of lung adenocarcinoma (LUAD) with only the EGFR-T790M primary mutation. MethodsThe clinical data of all LUAD patients with only the EGFR-T790M primary mutation were collected. Immunohistochemical staining was performed on cell cycle-related proteins, targeted therapy indicators, and prognosis-related proteins in the specimens obtained from puncture biopsies or surgeries. ObjectivesThe aim of this study is to analyze the clinicopathological features and possible physiological mechanisms of only the EGFR-T790M primary mutation in LUAD, and to offer recommendations for clinical management. ResultsTwo patients who have only the T790M de novo mutation were both female (2/12,928, 0.02%). β-catenin and Cyclin D1 were both highly expressed. In case 1, IHC results showed a positive Ki67 and mutant P53 and there was a significant increase in serum CYFRA 21–1. Third-generation of EGFR TKIs resulted in a partial response (PR) time of less than 8 months in case 1. In case 2, the patient underwent surgical resection and adjuvant chemotherapy, resulting in a progression-free survival (PFS) time of 25 months. ConclusionThe results suggest that abnormal activation of the Wnt signaling pathway may be specifically associated with the EGFR-T790M primary mutation in LUAD. Furthermore, it has been observed that patients with significant Ki67, mutant P53, and CYFRA 21–1 expression tend to have a poor prognosis.

"ACHILLES" Heel No More? Afatinib at 40 Mg Once Daily is Superior to Platinum-Based Chemotherapy in EGFR Uncommon (G719X, S768I, and L861Q) Mutations (ACHILLES/TORG1834).

Afatinib, a second-generation covalent EGFR TKI, has been approved for the treatment of the three "uncommon" EGFR mutations (G719X, S768I, and L861Q) based on one pooled retrospective analysis of three prospective trials (LUX-Lung 2, 3 and 6). The confirmed overall response rate, as assessed by independent radiology review, was 66% (95% confidence interval: 47-81). Among the 21 responders, the proportion of patients with response duration of ≥12 months was 52% and the proportion with response durations of ≥18 months was 33%. Of note, all patients received afatinib at 40 or 50 mg once daily which is higher than the approved dose of 40 mg once daily and the usual 30 mg once daily starting dose by most thoracic oncologists. Given the approval of afatinib for "uncommon" EGFR mutations was based on the limited number of patients analyzed, the retrospective nature of the analysis, lack of randomized phase 2 or 3 trial, there remains uncertainty as to whether afatinib, chemotherapy or other next-generation EGFR TKIs is the optimal treatment. This uncertainty also hinders the development of future treatment of these "uncommon" mutations because of the uncertainty that afatinib is the optimal treatment and hence should be the standard of care control arm in future randomized trials. Finally, the ACHILLES/TORG1834 provided us with the first randomized trial result that afatinib achieved superior progression-free survival over platinum-based chemotherapy (10.6 months vs 5.7 months, HR = 0.42; 95% CI: 0.256-0.694; P = 0.0007). However, ACHILLES should mostly be considered as phase 2 trial given the limited number (N = 109) of patients enrolled. Furthermore, the PFS benefit seemed to be with the 40 mg daily dose (HR = 0.128; 95% CI: 0.050-0.327) and not with the 30 mg daily dose (HR = 0.704; 95% CI: 0.352-1.406). Further investigation of the 30 once daily dosing for the treatment of uncommon EGFR mutations is needed.

Abstract LB453: Distinct mechanism of CXCR7 activation in EGFR-mutated NSCLC by chemokines

Abstract Erlotinib and gefitinib, EGFR TKIs, have markedly improved outcomes for NSCLC patients with EGFR mutations. However, resistance eventually develops, with the T790M mutation evident in over 50% of resistant tumors. Other resistance pathways include MET amplification, SCLC transformation, and EMT. Osimertinib, a third-generation EGFR TKI, targets the T790M mutation and is approved as a first-line treatment, reducing the incidence of T790M-related resistance. Nonetheless, non-T790M resistance mechanisms such as mesenchymal transformation are on the rise. The molecular targets or exact mechanisms of EGFR TKI resistance with mesenchymal phenotypes remain elusive. We have discovered that ERK reactivation, commonly found in EGFR TKI-resistant cells with a mesenchymal phenotype, is due to activation of an atypical GPCR, CXC chemokine receptor type 7 (CXCR7). CXCR7 is overexpressed in a cell line, an EGFR TKI-resistant tumor model, and in samples from patients that progressed on EGFR TKIs. Currently, there are no effective CXCR7 inhibitors to evaluate in NSCLC; the mechanisms and ligands for CXCR7 are not fully understood. To evaluate ligand-dependent activation of CXCR7, we generated HEK293 cells and EGFR-mutant NSCLC cells ectopically-expressing CXCR7 and stimulated the cells with CXCL12, a well-documented ligand for CXCR7. Exposures of HEK293 cells with CXCR7 to CXCL12 resulted in the internalization of CXCR7 followed by the activation of the MAPK pathway within 30 minutes of EGFR TKI treatment whereas MAPK activation in EGFR mutant NSCLC cells took 8 hours. MIF activation was also delayed in NSCLC compared to the HEK293 model, requiring the presence of an EGFR TKI. We discovered that CXCR7 co-immunoprecipitated with mutant EGFR in NSCLC cells while CXCR7 did not co-immunoprecipitate when EGFR was inhibited. Furthermore, we discovered additional chemokines including GDF15 that activate the CXCR7-MAPK axis and promote cell migration, a key characteristic of the mesenchymal phenotype in EGFR mutant cells. Taken together, we elucidated a unique mechanism of ligand-induced activation of CXCR7 and downstream MAPK pathway by canonical and putative ligands. This complex mechanism of CXCR7 activation in EGFR mutant NSCLC suggests that preventing the receptor-ligand binding may not be feasible in the context of overcoming EGFR TKI resistance. Citation Format: Laura C. Gunder, Ines Pulido, Jeffrey H. Becker, Malek G. Massad, Takeshi Shimamura. Distinct mechanism of CXCR7 activation in EGFR-mutated NSCLC by chemokines [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 2 (Late-Breaking, Clinical Trial, and Invited Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(7_Suppl):Abstract nr LB453.

Abstract CT280: FURVENT, Phase 3 trial testing furmonertinib vs chemotherapy as first-line treatment for advanced NSCLC with EGFR exon 20 insertions (FURMO-004)

Abstract Introduction: EGFR exon 20 insertion mutations occur in approximately 2% of non-small cell lung cancer (NSCLC) and overall account for approximately 9% of all the EGFR mutations in NSCLC (Robichaux et al., 2021). Current first-line standard of care for NSCLC patients with these mutations is platinum-based chemotherapy (NCCN NSCLC, 2023). Furmonertinib is an oral, highly brain penetrant, broadly active mutant-selective EGFR inhibitor that targets EGFR exon 20 insertions and other EGFR mutations (Musib et al., NACLC 2022). Furmonertinib recently obtained FDA Breakthrough Therapy Designation for the first line treatment of patients with advanced NSCLC with EGFR ex20ins based on the data from the FAVOUR study. Promising preliminary clinical activity was observed in the FAVOUR study testing furmonertinib (240 mg daily [QD]) in patients with treatment naïve locally advanced or metastatic NSCLC, with EGFR exon 20 insertion (ex20ins) mutations showing confirmed overall response rate (ORR) of 78.6% (n=28) by blinded independent central review (BICR) with a preliminary median DOR of 15.2 months (Han et al., WCLC 2023). In previously treated patients both the 240 mg and 160 mg QD dose levels were active with confirmed ORR of 46.2% (n=26) and 38.5% (n=26) respectively, and included patients harboring near and far loop mutations.Furmonertinib showed a generally well-tolerated safety profile with expected EGFR-TKI class toxicities. Additional furmonertinib preclinical data in uncommon EGFR mutations, including P-loop and αC-helix Compressing (PACC) and ex20ins mutations will be presented at the AACR 2024 Annual Meeting (Nilsson et al., AACR 2024 Abstract #4174). Methods: The FURVENT (FURMO-004) study is a registrational global, phase 3, randomized, multicenter, open-label study. Eligible patients havetreatment-naïve, locally advanced or metastatic non-squamous NSCLC with EGFR exon 20 insertion mutations. Key inclusion criteria include documented EGFR exon 20 insertion mutation and measurable disease per RECIST 1.1. Key exclusion criteria include prior systemic anticancer therapy in the locally advanced or metastases setting or any prior EGFR TKI therapy. Approximately 375 patients will be randomized 1:1:1 to receive furmonertinib 160 mg QD, furmonertinib 240 mg QD, or platinum-based chemotherapy (cisplatin or carboplatin plus pemetrexed for 4 cycles followed by pemetrexed maintenance therapy). Stratification factors include the history or presence of central nervous system metastases at baseline, geographic region, and sex at birth. Patients from the platinum-based chemotherapy arm with documented disease progression are eligible to participate in the crossover phase of this trial to furmonertinib therapy. The primary endpoint is progression-free survival comparing between the treatment arms (furmonertinib 160 mg or 240 mg vs chemotherapy) based on BICR assessment. The key secondary endpoint is overall survival. Study enrollment is ongoing. Clinical trial information: NCT05607550. Citation Format: Alexander Spira, Byoung Chul Cho, Enriqueta Felip, Edward Garon, Koichi Goto, Melissa Lynne Johnson, Natasha B. Leighl, Antonio Passaro, David Planchard, Sanjay Popat, James Yang, Xiaoqian Lu, Yong Jiang, Jack Huang, Morgan Lam, Marcin Kowanetz, Shirley Wang, John Le, Jerry Hsu, Caicun Zhou. FURVENT, Phase 3 trial testing furmonertinib vs chemotherapy as first-line treatment for advanced NSCLC with EGFR exon 20 insertions (FURMO-004) [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 2 (Late-Breaking, Clinical Trial, and Invited Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(7_Suppl):Abstract nr CT280.

Monolayer culture alters EGFR inhibitor response through abrogation of microRNA-mediated feedback regulation

Ex vivo drug screening is a potentially powerful tool for the future of cancer care, but the accuracy of results is contingent on the culture model. Both monolayer (2D) and spheroid (3D) culture systems offer advantages, but given the differences in mechanical environment, we hypothesized that that the suitability of one system over another would be critical for screening drugs with mechanical targets in mechanical tissues. HCC827 lung adenocarcinoma cells were challenged with EGFR tyrosine kinase inhibitors in monolayer and spheroid culture. RNA sequencing was performed on cells in both conditions to assess culture-induced transcriptional changes that could account for differences in drug response and differences in EGFR expression detected by immunostain. A microRNA microarray was performed to assess culture-induced differences in regulation of microRNA, and the impact of miR-146a-5p on drug response was verified by inhibition. Results were confirmed in human lung adenocarcinoma tissue. HCC827 spheroids were resistant to erlotinib and gefitinib, but significantly more sensitive in 2D culture. RNA-seq and immunostaining show a discrepancy in EGFR transcript and protein expression between the two conditions, which we attribute to miR-146a-5p. This microRNA targets EGFR and is differentially expressed between 2D and 3D culture. Inhibition of miR-146a-5p significantly increased erlotinib cytotoxicity, but validation in patient-derived spheroids suggests that the effect may be mutation-specific. Analysis of RNA-seq data suggests that cells in 2D culture become highly dependent on EGFR signaling to drive proliferation and cell spreading, resulting in a misleading level of sensitivity to EGFR TKIs, while the same cells in spheroid culture retain microRNA-driven EGFR feedback regulation that leaves them less vulnerable to EGFR inhibition. These findings underscore the need for close scrutiny of culture-induced effects on drug target regulation in model design for ex vivo drug screening.

Abstract 5204: Exploring the therapeutic potential of EGFR retreatment: A comprehensive analysis of T790m(+) conversion and prognosis in lung cancer patients

Abstract Background: T790M acquired resistance occurs in 30-40% of cases after first- or second-generation EGFR TKI treatment. However, some patients who did not develop T790M mutation are converted to T790M positive through EGFR TKI retreatment. We conducted a Phase II prospective study analyzing T790m (+) conversion and prognosis in patients who were not induced T790M mutation at 2nd biopsy and were re-treated with first-generation EGFR-TKI as the third-line or later therapy. Methods: We re-administered first-generation EGFR-TKI to 63 patients (gefitinib n=34 or erlotinib n=29) who had previously been treated with first- or second- generation EGFR TKIs and cytotoxic chemotherapy because they were T790M-negative at the 2nd biopsy. Results: Among the 63 patients, a new T790m (+) mutation was identified in 20 patients (32%) with EGFR TKI retreatment. The first EGFR TKI treatment period and EGFR TKI retreatment period were significantly longer in the T790m (+) group than in the T790m (-) group (P-value=0.026, P-value=0.029, respectively). The best response to retreatment was also favorable in the T790m (+) group (P-value=0.038). The median overall survival (OS) in the T790m (+) group was 29.3 months, which was significantly better than the 6.0 months observed in the T790m (-) group (P-value&amp;lt;0.001). In an additional NGS analysis conducted on stored plasma samples from the 24 patients who were negative for T790M in the tumor tissue before retreatment, T790M was detected in five patients. These patients, who were subsequently treated with a third EGFR TKI, demonstrated very favorable overall survival (OS). Conclusions: EGFR retreatment could induce T790m (+) conversion in approximately one-third of cases, and these patients exhibited favorable prognosis. Through NGS analysis using plasma samples, approximately 20% cases of T790m mutation, which were not detected through routine PCR tests at the tumor tissue, could be identified. Retreatment-EGFR TKI and NGS analysis through blood samples could improve patient prognosis through the additional discovery of T790m (+) mutation. Citation Format: Joong Jin Ahn, Jae Cheol Lee, Chang Min Choi, In Ae Kim, Kye Young Lee, Jeong Eun Lee, Seung Hoon Jang, Seong Hoon Yoon, In Jae Oh, Sang Hoon Lee, Eun Young Kim, Juwhan Choi, Sung Yong Lee. Exploring the therapeutic potential of EGFR retreatment: A comprehensive analysis of T790m(+) conversion and prognosis in lung cancer patients [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 5204.

Abstract 1967: IN-119873, the next-generation allosteric EGFR TKI, a potent and highly selective EGFR L858R for the treatment of osimertinib-resistant NSCLC

Abstract EGFR mutations occur in approximately 50% of Asian patients and 20% of Caucasian patients with non-small cell lung cancer (NSCLC). The EGFR L858R mutation constitutes approximately half of the EGFR-mutated patients, and despite receiving first-line or second-line treatment with the 3rd generation EGFR TKI osimertinib, they continue to exhibit a poor prognosis. According to real-world analysis, the leading resistance mechanism to osimertinib is identified as EGFR C797S mutation. Furthermore, osimertinib is still associated with gastrointestinal and skin toxicity, despite its improved selectivity for EGFR WT compared to 1st-generation EGFR TKIs. Here, we show that IN-119873 can overcome C797S-mediated acquired resistance based on the results obtained by various in vitro and in vivo NSCLC models. IN-119873 binds to an EGFR allosteric site separate from the ATP-binding site with a remarkable preference for highly mutant-selective inhibition. It effectively targets EGFR L858R activating mutations while sparing the inhibition of EGFR WT, which sets it apart from ATP competitive inhibitors. Moreover, oral administration of IN-119873 showed excellent anti-tumor efficacy in a dose-dependent manner in a diverse of osimertinib-resistant CDX and PDX models. IN-119873 also demonstrated favorable blood-brain-barrier penetration with promising intracranial efficacy in the H1975-luc brain metastasis model both mono or in combination with osimertinib. As a selective, orally available, and CNS-penetrable next-generation allosteric EGFR-TKI, IN-119873 is currently undergoing IND-enabling studies and has the potential to demonstrate activity in both first-line and resistance settings, either as a monotherapy or in combination with 3rd generation EGFR TKI. Citation Format: Jong Ryoul Choi, Daseul Yoon, Seo Hyun Kim, Do Gyeong Kim, Seock Yong Kang, Seong-Il Choi, Somyi Park, Hyun Kyung Lee, Donghyun Kim, Ju Hyun Lee, Hye-Jung Kim, Bong Tae Kim. IN-119873, the next-generation allosteric EGFR TKI, a potent and highly selective EGFR L858R for the treatment of osimertinib-resistant NSCLC [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 1967.

Abstract 4663: Establishing the role of PRMT5 in lung cancer tumorigenicity and modulation of expression in smokers

Abstract Studies show that PRMT5 (protein arginine methyl transferase 5) is responsible for increased tumorigenicity by activation of the PI3K/Akt signaling pathway promoting increased cancer cell proliferation. However, the role of PRMT5 in modulating EGFR TKI resistance is minimally studied. We hypothesize that over-expression of PRMT5 could promote tumorigenesis and TKI resistance by activating PI3K-Akt-mTOR signaling pathways. Hence, modulating this key biomarker may help reduce tumorigenicity and overcome TKI resistance. We performed qPCR to study the expression of PRMT5 in normal lung cells and NSCLC cell lines. We also compared the expression of these biomarkers in erlotinib resistant (ER) and Osimertinib resistant (OR) cells using Western blotting. PRMT5 was inhibited using GSK591 (PRMT5i) to evaluate its sensitivity to EGFR TKIs (ER and OR). PRMT5 expression in normal lung cells and NSCLC cells treated with Cigarette smoke extract (CSE) were also studied and correlated with immunostaining results from smoker and non-smoker lung tumor tissue samples. Changes in PRMT5 expression were analyzed in WT-EGFR lung cancer cell lines (H358, H2170), mutant EGFR lung cancer cell lines (H3255, H1975, PC9) and normal lung fibroblast cells (HLF). PRMT5 expression was upregulated by 1.6-2.1 fold in HLF, H2170 and H358 cells after 1 week of treatment with CSE. CSE treatment also upregulated expression of inflammatory cytokines (IL-1β, IL-8 and TNF-α) in H358 cells by 1.6-7 fold as analyzed by qPCR. PRMT5 expression was upregulated in EGFR-TKI resistant cell lines, by 1.5-1.9 fold in PC9ER, PC9OR and H2170ER cells, compared to parental cells. Similar results were found using qPCR, with 1.6-2.3 fold increase in PRMT5 mRNA expression in H2170OR, PC9ER/OR and H3255OR cells compared to parental cells. An MTT assay was done to assess percentage viability of cells after treatment of PRMT5i. While 2μM PRMT5i treatment of PC9OR cells decreased cell viability by 42%, an inhibitory effect that was more than additive was seen with a combination of 2μM of PRMT5i and 21nM of OR. Similar results were also observed in H2170ER cells. Migratory properties of OR resistant cells, were studied by wound healing assays. Percentage wound area in PRMT5i treated PC9OR cells was 29.3% as compared to 6.1% and 10.5% in diluent and OR treated cells respectively after 48 hrs. Combination treatment of PRMT5i and OR further inhibited cell migration with higher wound area of 41.7%. Immunostaining of lung tumor sections from smokers and non-smokers showed high expression of PRMT5 localized in the cytoplasm and nucleus. Microscopic analysis of 20 tumor sections from smokers showed higher expression of PRMT5 (p&amp;lt;0.05) compared to non-smokers. We can conclude that PRMT5 is upregulated in TKI resistant cells causing tumorigenesis. Modulation of PRMT5 can prove to be groundbreaking and revolutionary, as it may increase the efficacy of EGFR TKIs. Citation Format: Syed N. Ali, Meet Patel, Bamby Dieng, Cody Lund, Neelu Puri. Establishing the role of PRMT5 in lung cancer tumorigenicity and modulation of expression in smokers [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 4663.

Abstract 2617: BCG022, a novel HER3 × MET bispecific antibody-drug conjugate (bsADC), demonstrates promising anti-tumor efficacy

Abstract HER3 and MET expression act as bypass resistance mechanisms, conferring resistance to multiple therapeutic agents, such as EGFR TKI treatment. HER3 and MET are also co-expressed at high prevalence in multiple tumor types, including gastric, colorectal, breast, and non-small-cell lung cancer (NSCLC). In addition, HER3 and MET are frequently overexpressed in liver metastases from patients with colorectal cancer, indicating that targeting both targets may provide clinical benefit. We previously reported generation of a fully human bispecific antibody (bsAb) targeting HER3 and MET using RenLite® mice, which contain the full human heavy chain variable domain with a common human kappa light chain to facilitate bispecific antibody assembly. This bsAb demonstrated reactivity to human and cynomolgus monkey antigens and binding to multiple cancer cell lines, including NSCLC, gastric, colorectal, and hepatocellular cancer cell lines. The bsAb also showed enhanced internalization activity compared to parental monovalent antibodies in the NUGC-4 cell line expressing HER3 and MET. Here, we evaluated the efficacy of the bsAb when conjugated to two distinct payloads: vcMMAE and BLD1102, Biocytogen’s novel, proprietary linker/payload system composed of a DNA Topo I inhibitor payload (BCPT02) and a highly hydrophilic protease-cleavable linker. The in vivo efficacy of BCG022-vcMMAE and BCG022-BLD1102 was evaluated in cell-derived NSCLC and gastric cancer xenografts, and in patient-derived gastric and pancreatic xenograft models. Both demonstrated strong anti-tumor activity, with efficacy greater than or comparable to benchmark ADCs. Taken together, these promising preclinical results suggest that the BCG022 bsADC could be a novel treatment for HER3 and MET co-expressing tumors. Citation Format: Zhuolin Li, Chengzhang Shang, Zhenyan Han, Gao An, Chaoshe Guo, W. Frank An, Yi Yang. BCG022, a novel HER3 × MET bispecific antibody-drug conjugate (bsADC), demonstrates promising anti-tumor efficacy [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 2617.

Abstract 1964: Furmonertinib is a brain-penetrant EGFR TKI highly active in uncommon EGFR mutations, including PACC and exon 20 insertions

Abstract Background: Furmonertinib (AST2818, furmo) is an oral, highly brain-penetrant, and broadly active mutation-selective EGFR inhibitor against both classical and uncommon EGFR mutations (mts). Furmo has demonstrated promising interim efficacy and safety in non-small cell lung cancer (NSCLC) patients (pts) with EGFR exon 20 insertion (ex20ins) mts (Han et al., 2023). Furmo is currently being studied in a global Phase 3 trial for 1st line pts with ex20ins in NSCLC (FURVENT; NCT05607550) and has received FDA Breakthrough Designation in this pt population. P-loop and αC-helix Compressing (PACC) mts represent another subset of uncommon EGFR mts (Robichaux et al., 2021) that are similar to ex20ins in narrowing the drug binding pocket; include e.g. G719X, S768I, E709X, L747X, V774M; and are found as single or compound EGFR mts. Treatment options for pts with PACC mts remain limited. In this study, we further characterized PACC mts as cancer drivers in NSCLC and evaluated the pre-clinical activity and binding mechanisms of furmo in PACC and ex20ins mts. Methods: AACR Project GENIE and TEMPUS databases were used for mutation analysis. In vitro potency was determined in Ba/F3 cell lines for 33 PACC and 16 ex20ins mts. In vivo efficacy was conducted in pt-derived xenografts (PDXs). Molecular modeling was performed using MOE software. Results: PACC prevalence was 2.4% vs. 1.6% for ex20ins and 14% for classical EGFR mts in all NSCLC, corresponding to 10.4% PACC and 7% ex20ins of all EGFR mts. Co-mutation analysis revealed that other oncogenes, such as p53, co-occurred alongside PACC to a similar rate as with ex20ins and classical EGFR mts which further supports the role of PACC mts as a similar cancer driver as other EGFR mts in NSCLC. Ba/F3 cell lines harboring PACC mts were highly sensitive to furmo which showed overall superior potency vs. osimertinib and similar activity to afatinib. When comparing the mutant/wild-type IC50 ratio, furmo showed promising and high activity against single (e.g. G719X) and compound (e.g. ex19del+L718V) PACC mts. IC50 values were similar for PACC as compared to ex20ins mts. Therefore, furmo is predicted to be broadly active across both PACC and ex20ins mutant pt populations at clinically achievable drug levels. Molecular modelling revealed that furmo’s interaction with ex20ins and PACC mts is stabilized through hydrogen bonds with specific sites and its proximity to hydrophobic residues including L792 and P794 in the drug binding pocket. To further characterize furmo sensitivity in vivo against PACC mts, studies in PDXs are ongoing to evaluate efficacy, pharmacokinetics and pharmacodynamics and will be presented. Conclusions: PACC mts are important and prevalent cancer drivers in NSCLC and furmo is similarly active preclinically against both PACC and ex20ins mts. The activity of furmo in EGFR PACC mutant NSCLC is currently being evaluated in a global study FURTHER (NCT05364073). Citation Format: Monique B. Nilsson, Zineb Mounir, Luna Musib, Junqin He, Xiaoxing Yu, Qing Li, Huibing Luo, John V. Heymach, Jerry Y. Hsu, Stuart Lutzker, Xiuning Le, Marcin Kowanetz. Furmonertinib is a brain-penetrant EGFR TKI highly active in uncommon EGFR mutations, including PACC and exon 20 insertions [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 1964.

Abstract 6589: Discovery of potent and selective pan-TEAD autopalmitoylation inhibitors for the treatment of Hippo-pathway altered cancers

Abstract TEAD1-4 are DNA bound transcription factors regulated by the Hippo tumor suppressor pathway that bind the coactivators YAP/TAZ to activate oncogenic gene expression programs involved in cell survival, proliferation, and drug resistance. TEAD-dependent transcription is activated in many tumor types through a variety of mechanisms including LOF Hippo pathway mutations (e.g. NF2, LATS) and YAP/TAZ amplification, and also as an adaptive resistance mechanism, for example in response to EGFR TKI and KRAS inhibition. Here, we report the initial characterization of a novel pan-TEAD inhibitor, AZ4331, which was identified following a structure-guided drug design campaign. AZ4331 disrupts the post-translational palmitoylation of TEAD proteins through covalent binding to a conserved cysteine residue resulting in inhibition of TEAD-dependent transcriptional output. AZ4331 inhibited the proliferation of NF2m NCI-H226 cells (GI50: 92 nM) while having no effect on Hippo-wild type NCI-H2452 (GI50: undetermined). Cell-based metabolic labeling studies demonstrated the ability of AZ4331 to inhibit palmitoylation of all four TEAD paralogs and led to disruption of the YAP/TEAD complex assessed by immunoprecipitation resulting in reduced TEAD transcriptional output as assessed by qPCR. Furthermore, in vivo profiling showed AZ4331 achieved sufficient exposures (plasma free Cmax: 2.7 µM) and robust target engagement as measured through reduction of multiple canonical TEAD target genes (CTGF [IC50: 0.127 µM], ANKRD1, AMOTL2 and CYR61) in Hippo-altered mesothelioma xenograft tumors. This target engagement in turn drove inhibition of tumor proliferation in xenograft models representing common Hippo-alterations. AZ4331 treatment of NF2m NCI-H226 and LATS1/2 loss MSTO-211H mesothelioma xenografts drove 50% and 93% regression of tumors, respectively. While treatment of head and neck squamous cell carcinoma FAT1m FaDu and YAP1amp Detroit562 xenografts lead to 58% tumor growth inhibition and 35% tumor regression, respectively. These findings identify AZ4331 as a potent inhibitor of the TEAD transcription factor family and further validate the inhibition of TEAD in Hippo-altered cancers as a potential therapeutic strategy. Citation Format: Jacob A. Gordon, Jolanta Dubauskaite, Michelle DuPont, Nin Guan, Geoff Holdgate, Scott Mlynarski, Neil Umbreit, Danielle Sanchez, Abhishek Srivastava, Janek Suski, Nancy Su, Ryan Richards, Sabina Cosulich, Corinne Reimer, James Brownell. Discovery of potent and selective pan-TEAD autopalmitoylation inhibitors for the treatment of Hippo-pathway altered cancers [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 6589.

Uncommon de novo EGFRT790M-Mutant NSCLC characterized with unique genetic Features: Clinical response and acquired resistance to the third-generation EGFR-TKIs treatment

IntroductionThe literature on de novo EGFRT790M-mutant patients diagnosed with lung cancer is limited, and there is currently no consensus concerning the most effective treatment protocols. This study aimed to investigate the genomic characteristics of de novoEGFRT790M-mutant non-small cell lung cancer (NSCLC) and provide insights into its clinical response and resistance mechanism to third-generation EGFR-TKIs. MethodsNext-generation sequencing was utilized to screen a substantial cohort of 4,228 treatment-naïve patients from the Mygene genomic database to identifythe de novo EGFR-T790M mutation. Meanwhile, we recruited 83 individuals diagnosed with lung cancer who harbored de novo EGFRT790M mutation in the real world. In addition, 166 patients who acquired EGFR-T790M mutation after becoming resistant to first- or second-generation EGFR-TKIs were included as a comparison cohort. ResultsDe novo EGFRT790M mutation identified by next-generation sequencing is rare (∼1.3 %) in Chinese lung cancer patients. The relative variant allele frequency (VAF) of de novo EGFRT790M mutation was either comparable to or significantly lower than those of EGFR-activating mutations. Patients with de novo-T790M mutations exhibited less favorable clinical outcomes when administered third-generation EGFR-TKIs as first-line therapy thanthose with 19del mutationsdue to a high overlap rate in EGFR p.L858R mutation. In patients with a de novo EGFRT790M mutation, no correlation was observed between T790M clonality and treatment outcomes with third-generation EGFR-TKIs. In contrast, the sub-clonality of the T790M mutation detrimentally affected the third-generation EGFR-TKI treatment efficacy in patients with acquired T790M mutation. Potential resistance mechanisms of third-generation EGFR TKIs in NSCLC patients with de novo or acquired EGFRT790M mutations included EGFR p.C797S in cis or EGFR p.E709X mutation, as well as activation of bypass pathways. ConclusionsThe present study characterized the uncommon but unique de novo EGFRT790M-mutant NSCLC and laid a foundation for designing future clinical trials in the setting of uncommon EGFR mutation.

127P Waning effect of adjuvant EGFR TKIs in resected EGFR-mutated (EGFR-m) NSCLC: A systematic review and meta-analysis of randomized clinical trials (RCTs)

127P Waning effect of adjuvant EGFR TKIs in resected EGFR-mutated (EGFR-m) NSCLC: A systematic review and meta-analysis of randomized clinical trials (RCTs)

The difference between dacomitinib and afatinib in effectiveness and safety in first-line treatment of patients with advanced EGFR-mutant non-small cell lung cancer: a real-world observational study

ObjectivesThe irreversible epidermal growth factor receptor tyrosine kinase inhibitors (EGFR TKIs) afatinib and dacomitinib are approved for first-line treatment of EGFR mutation-positive non-small cell lung cancer (NSCLC). We aimed to compare the efficacy and safety of afatinib and dacomitinib in this setting.Materials and methodsBetween September 2020 and March 2023, we retrospectively recruited patients diagnosed with advanced-stage EGFR-mutant NSCLC who were treated with first-line irreversible EGFR-TKIs. The enrolled patients were assigned to two groups based on whether they received afatinib or dacomitinib.ResultsA total of 101 patients were enrolled in the study (70 to afatinib and 31 to dacomitinib). The partial response rates (PR) for first-line treatment with afatinib and dacomitinib were 85.7 and 80.6% (p = 0.522). The median progression-free survival (PFS) (18.9 vs. 16.3 months, p = 0.975) and time to treatment failure (TTF) (22.7 vs. 15.9 months, p = 0.324) in patients with afatinib and dacomitinib treatment were similar. There was no significant difference observed in the median PFS (16.1 vs. 18.9 months, p = 0.361) and TTF (32.5 vs. 19.6 months, p = 0.182) between patients receiving the standard dose and those receiving the reduced dose. In terms of side effects, the incidence of diarrhea was higher in the afatinib group (75.8% vs. 35.5%, p < 0.001), while the incidence of paronychia was higher in the dacomitinib group (58.1% vs. 31.4%, p = 0.004). The PFS (17.6 vs. 24.9 months, p = 0.663) and TTF (21.3 vs. 25.1 months, p = 0.152) were similar between patients younger than 75 years and those older than 75 years.ConclusionThis study showed that afatinib and dacomitinib had similar effectiveness and safety profiles. However, they have slightly different side effects. Afatinib and dacomitinib can be safely administered to patients across different age groups with appropriate dose reductions.

Translational insights and overall survival in the U31402-A-U102 study of patritumab deruxtecan (HER3-DXd) in EGFR-mutated NSCLC

Human epidermal growth factor receptor 3 (HER3) is broadly expressed in non-small-cell lung cancer (NSCLC) and is the target of patritumab deruxtecan (HER3-DXd), an antibody-drug conjugate consisting of a HER3 antibody attached to a topoisomerase I inhibitor payload via a tetrapeptide-based cleavable linker. U31402-A-U102 is an ongoing phase I study of HER3-DXd in patients with advanced NSCLC. Patients with epidermal growth factor receptor (EGFR)-mutated NSCLC that progressed after EGFR tyrosine kinase inhibitor (TKI) and platinum-based chemotherapy (PBC) who received HER3-DXd 5.6 mg/kg intravenously once every 3 weeks had a confirmed objective response rate (cORR) of 39%. We present median overall survival (OS) with extended follow-up in a larger population of patients with EGFR-mutated NSCLC and an exploratory analysis in those with acquired genomic alterations potentially associated with resistance to HER3-DXd. Safety was assessed in patients with EGFR-mutated NSCLC previously treated with EGFR TKI who received HER3-DXd 5.6 mg/kg; efficacy was assessed in those who also had prior PBC. In the safety population (N= 102), median treatment duration was 5.5 (range 0.7-27.5) months. Grade ≥3 adverse events occurred in 76.5% of patients; the overall safety profile was consistent with previous reports. In 78/102 patients who had prior third-generation EGFR TKI and PBC, cORR by blinded independent central review (as per RECIST v1.1) was 41.0% [95% confidence interval (CI) 30.0% to 52.7%], median progression-free survival was 6.4 (95% CI 4.4-10.8) months, and median OS was 16.2 (95% CI 11.2-21.9) months. Patients had diverse mechanisms of EGFR TKI resistance at baseline. At tumor progression, acquired mutations in ERBB3 and TOP1 that might confer resistance to HER3-DXd were identified. In patients with EGFR-mutated NSCLC after EGFR TKI and PBC, HER3-DXd treatment was associated with a clinically meaningful OS. The tumor biomarker characterization comprised the first description of potential mechanisms of resistance to HER3-DXd therapy.

Andrographolide sensitizes KRAS-mutant colorectal cancer cells to cetuximab by inhibiting the EGFR/AKT and PDGFRβ/AKT signaling pathways

BackgroundCetuximab, an inhibitor targeting EGFR, is widely applied in clinical management of colorectal cancer (CRC). Nevertheless, drug resistance induced by KRAS-mutations limits cetuximab's anti-cancer effectiveness. Furthermore, the persistent activation of EGFR-independent AKT is another significant factor in cetuximab resistance. Nevertheless, the mechanism that EGFR-independent AKT drives cetuximab resistance remains unclear. Thus, highlighting the need to optimize therapies to overcome cetuximab resistance and also to explore the underlying mechanism. PurposeThis work aimed to investigate whether and how andrographolide enhance the therapeutic efficacy of cetuximab in KRAS-mutant CRC cells by modulating AKT. MethodsThe viabilities of CRC cell lines were analyzed by CCK-8. The intracellular proteins phosphorylation levels were investigated by Human Phospho-kinase Antibody Array analysis. Knockdown and transfection of PDGFRβ were used to evaluate the role of andrographolide on PDGFRβ. The western blotting was used to investigate Wnt/β-catenin pathways, PI3K/AKT, and EMT in KRAS-mutant CRC cells. The animal models including subcutaneous tumor and lung metastasis were performed to assess tumor response to therapy in vivo. ResultsAndrographolide was demonstrated to decrease the expression of PI3K and AKT through targeting PDGFRβ and EGFR, and it enhanced cetuximab effect on KRAS-mutant CRC cells by this mechanism. Meanwhile, andrographolide helped cetuximab to inhibit Wnt/β-catenin, CRC cell migration and reduced Vimentin expression, while increasing that of E-cadherin. Lastly, co-treatment with cetuximab and andrographolide reduced the growth of KRAS-mutant tumors and pulmonary metastases in vivo. ConclusionsOur findings suggest that andrographolide can overcome the KRAS-mutant CRC cells' resistance to cetuximab through inhibiting the EGFR/PI3K/AKT and PDGFRβ /AKT signaling pathways. This research provided a possible theory that andrographolide sensitizes KRAS-mutant tumor to EGFR TKI.

The third-generation EGFR TKI osimertinib could be a promising neoadjuvant therapy in patients with resectable EGFR-mutant NSCLC

The third-generation EGFR TKI osimertinib could be a promising neoadjuvant therapy in patients with resectable EGFR-mutant NSCLC

Targeting HER3 to overcome EGFR TKI resistance in NSCLC.

Receptor tyrosine kinases (RTKs) play a crucial role in cellular signaling and oncogenic progression. Epidermal growth factor receptor tyrosine kinase inhibitors (EGFR TKIs) have become the standard treatment for advanced non-small cell lung cancer (NSCLC) patients with EGFR-sensitizing mutations, but resistance frequently emerges between 10 to 14 months. A significant factor in this resistance is the role of human EGFR 3 (HER3), an EGFR family member. Despite its significance, effective targeting of HER3 is still developing. This review aims to bridge this gap by deeply examining HER3's pivotal contribution to EGFR TKI resistance and spotlighting emerging HER3-centered therapeutic avenues, including monoclonal antibodies (mAbs), TKIs, and antibody-drug conjugates (ADCs). Preliminary results indicate combining HER3-specific treatments with EGFR TKIs enhances antitumor effects, leading to an increased objective response rate (ORR) and prolonged overall survival (OS) in resistant cases. Embracing HER3-targeting therapies represents a transformative approach against EGFR TKI resistance and emphasizes the importance of further research to optimize patient stratification and understand resistance mechanisms.