EGFR WT Research Articles

Abstract PR004: Brain penetrant allosteric EGFR inhibitors for NSCLC

Abstract Approximately 30-50% of Non-Small Cell Lung Cancer (NSCLC) patients already have CNS disease at time of diagnosis or else develop it during treatment, and there remains a need for better outcomes in these patients. The 3rd-generation covalent EGFR inhibitor osimertinib is an effective therapy for NSCLC patients, improving upon 1st-generation inhibitors gefitinib and erlotinib, and achieving enhanced brain penetration relative to those agents. However, the survival benefit relative to the 1st-generation inhibitors is observed primarily in patients with exon19 deletions rather than the L858R mutation. We developed a series of mutant-selective allosteric EGFR inhibitors that specifically target the L858R mutation (and subsequent resistance mutations), with high selectivity over wt EGFR and across the kinome. Early compounds including the isoindolinone JBJ-09-063 demonstrated good in vivo efficacy in mouse tumor models, despite limited bioavailability. Diversification and optimization of the chemistry, involving a scaffold hopping approach and the replacement of the thiazole amide with benzimidazole, delivered a set of compounds with promising potency and rodent PK. A subset of these achieved good brain exposure in mice and efficacy in an intracranial H1975 brain metastasis model. The mutant-selectivity and ability to co-bind with osimertinib makes an allosteric EGFR inhibitor an ideal partner for combination therapy, with the potential to deliver enhanced outcomes in L858R-driven NSCLC, especially for patients with CNS disease. Citation Format: David Scott, Courtney Cullis, Tyler Beyett, Frederic Feru, Thomas Gero, Krista Gipson, Praful Gokhalle, Nathanael Gray, David Heppner, Sampson Huang, Pasi Jänne, Sandeepraj Pusalkar, Michael Eck. Brain penetrant allosteric EGFR inhibitors for NSCLC [abstract]. In: Proceedings of the AACR Special Conference in Cancer Research: Optimizing Therapeutic Efficacy and Tolerability through Cancer Chemistry; 2024 Dec 9-11; Toronto, Ontario, Canada. Philadelphia (PA): AACR; Mol Cancer Ther 2024;23(12_Suppl):Abstract nr PR004

OA16.03 Telisotuzumab Vedotin in Asian Patients with C-Met Protein-Overexpressing Non-Squamous EGFR WT NSCLC: Results from LUMINOSITY

OA16.03 Telisotuzumab Vedotin in Asian Patients with C-Met Protein-Overexpressing Non-Squamous EGFR WT NSCLC: Results from LUMINOSITY

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 2116: Telisotuzumab vedotin (Teliso-V)-mediated c-Met internalization, endolysosomal trafficking, and potent cytotoxic activity are unaffected by MET exon-14 skipping mutation

Abstract Background: Telisotuzumab vedotin (Teliso-V) is an antibody-drug conjugate (ADC) composed of a c-Met (MET protein) antibody coupled to the microtubule inhibitor monomethyl auristatin E (MMAE). Teliso-V was granted FDA Breakthrough Therapy Designation for advanced/metastatic EGFR WT, NSQ NSCLC with high c-MET overexpression. For MMAE drug delivery, Teliso-V must first undergo receptor internalization and endolysosomal (EL) trafficking. Hepatocyte growth factor (HGF)-dependent MET EL trafficking and degradation depend on the E3 ubiquitin ligase Casitas B-lineage lymphoma (CBL). METex14 skipping and CBL-binding site mutations, which delete the binding site for CBL, occur in ~ 3% of NSCLC. The role of CBL in Teliso-V-MMAE delivery and activity was assessed in this work. Methods: WT-human c-Met, c-Met-Y1003F/N (CBL binding site mutations in MET), and c-Met-ex14∆ (47 aa deletion to mimic ex14 skipping) or CBL-L620f, G807*, and W802* (CBL inactivating mutants) were expressed in NIH3T3, Ba/F3 cells, or A549 tumor cells using retroviral transduction. Genetically modified cells were then used to define the role of CBL in c-Met surface expression, intracellular signaling, EL trafficking (using pHrodo Red-labeled Teliso-V), and Teliso-V sensitivity in 2D/3D cell cultures. Results: c-Met expression was required for Teliso-V cytotoxicity and intracellular payload delivery in all cell lines. While minimal changes in cell surface c-Met levels were observed, CBL binding mutants had increased phosphorylated c-Met in the absence of HGF, and ex14∆-MET and CBL binding site mutants showed increased sensitivity to small molecule c-Met inhibitors. Compared to WT c-Met, ex14∆ and CBL-binding mutants showed similar EL trafficking and no change in sensitivity to Teliso-V. Co-treatment with a pan-CBL inhibitor also failed to alter Teliso-V EL trafficking and anti-tumor activity. Like most ADCs, EL trafficking was dependent on a dynamin-mediated process with reduced EL trafficking by co-treatment with Dyngo4a. To further understand the role of CBL in Teliso-V sensitivity, we expressed CBL inactivating mutations in A549 tumor cells. While the L602F and W802* mutants increased spheroid size, as well as activated p-MET, there was no change in sensitivity to Teliso-V. Conclusions: Loss of CBL-binding sites on c-Met via ex14 deletion or Y1003F/N leads to increased MET-targeted TKI sensitivity and increased phospho-c-Met levels but does not impact Teliso-V sensitivity or EL trafficking. Our results indicate that Teliso-V traffics to the EL via a dynamin-mediated process. Therefore, Teliso-V delivers MMAE through a robust ADC-mediated EL-dependent mechanism that is independent of CBL, suggesting that high c-Met expression in Ex14skipping or CBL binding site mutant NSCLC patients should be further investigated for response to Teliso-V. Citation Format: Izhar Batth, Ronald Pandoy, Shamim Khaja, Dolonchampa Maji, Tamar Uziel, Athan Vasilopoulos, Peter Ansell, PK Epling-Burnette. Telisotuzumab vedotin (Teliso-V)-mediated c-Met internalization, endolysosomal trafficking, and potent cytotoxic activity are unaffected by MET exon-14 skipping mutation [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 2116.

Abstract 4675: Reduction in NSCLC tumorigenesis by targeting sphingosine kinase 2

Abstract Lung cancer will account for 21% of US cancer deaths in 2023 with 238,340 cases and 127,070 deaths. Treatment with EGFR-TKI (epidermal growth factor receptor tyrosine kinase) inhibitors initially decrease tumor growth, but often leads to TKI resistance. According to studies, non-small cell lung cancer (NSCLC) tumors express more SphK2 (Sphingosine kinase 2) than normal lung tissue and patients with overexpression have worse survival chances. However, SphK2's role in TKI resistance is unclear. We hypothesize that inhibiting/downregulating SphK2 could reduce tumorigenicity and overcome ER (Erlotinib) and OR (Osimertinib) resistance. We studied the expression of SphK2 in both drug-resistant (OR/ER) and drug sensitive (parental) H358, H2170, H3255, and PC9 NSCLC cell lines using Western blotting, qRT-PCR, and immunofluorescence. H3255OR cells were also bioprinted with GelMA hydrogel using an R-Gen 200 bioprinter to mimic the physiological tumor environment and treated with SphK2 siRNA or ABC294640 (SphK2i). Immunoblotting was done to analyze changes in the expression of SphK2 in H358 (WT-EGFR) and H3255 (mutant EGFR- L858R) parental and OR-resistant cell lines. Results indicated a 1.5-1.8-fold upregulation of SphK2. Increased SphK2 gene expression was observed using qPCR in TKI-resistant H3255OR (4.3-fold), PC9ER/OR with mutant EGFR (E746-A750del) (1.8-3.3-fold), and H2170ER/OR with WT EGFR (1.3-1.5-fold) compared to parental cells. Immunofluorescence studies showed increased fluorescence of SphK2 in H3255OR (2.6-fold), H358 ER (2.4-fold) and OR cells (2.3-fold) compared to parental cells. Spheroids formed from single cancer cells can "re-create" the growth of a tumor. The spheroid count of H3255OR was reduced by 73.98% and 56%, respectively, when SphK2i was added to the 3D-cell culture with Matrigel, compared to the diluent and OR alone (p≤0.01). We used 3D bioprinting to precisely stack cells on biological scaffolds to recreate lung tumors from patients and boost the therapeutic efficacy of these findings. When bioprinted spheroids of H3255OR were treated with SphK2i in combination with OR, the number of spheroids per microscopic field were reduced by 87.3% compared to OR alone. Bioprinted H3255OR spheroids treated with SphK2 siRNA and OR revealed a 75.8% and 84% reduction of spheroid count, respectively, compared to treatments with siRNA alone or OR alone (p≤0.05). This data supports the hypothesis that SphK2 suppression or downregulation can assist in mitigating oncogenesis. We also used H3255OR transwell migration assays to examine how SphK2 inhibition affects cell migration. Combining OR with SphK2i resulted in a 94.7% and 91.4% decrease in cell migration compared to diluent and OR alone (p≤0.01). In H358OR-resistant cells, combining OR with SphK2i resulted in a 94.97% inhibition compared to diluent (p≤0.01). These results suggest that targeting SphK2 could be a valuable approach for treating lung cancer. Citation Format: Ayesha Khan, Bamby Dieng, Namrata Dube, Mohammad Fazle Alam, Neelu Puri. Reduction in NSCLC tumorigenesis by targeting sphingosine kinase 2 [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 4675.

Abstract 1980: Validation of a novel Type II HER2 inhibitor through preclinical studies across various cancer models

Abstract HER2 activation through amplification, overexpression or mutation drives many types of human cancers, and has been the target of several therapeutic approaches. The demonstration of clinical benefit of available pan-ERBB and HER2 inhibitors has been hampered by the dose-limiting side effects from their collateral or residual EGFR inhibition. Here we present IAM1363 (also known as ENT-H1), a highly potent and selective irreversible inhibitor of both HER2 wild-type and HER2 oncogenic mutants. IAM1363 binds to HER2 in a type II DFG-out conformation, the only example reported to date for this target. This binding mechanism underlies its strong interactions with HER2, including N-terminally truncated HER2 (p95HER2) and HER2 kinase domain mutants, with cellular IC50s in the low nanomolar range, while sparing WT EGFR. Oral administration of IAM1363 in mice led to tumor regression (TR) in a diverse set of HER2-driven tumor models at levels well below the maximum tolerated dose (MTD). Importantly, strong in vivo efficacy was observed in tumor models that exhibited resistance to the existing HER2-targeting agents. For example, in a p95HER2 xenograft model, IAM1363 caused significant TR, including complete responses, at 100 mg/kg dose, whereas tucatinib achieved at best tumor stasis at MTD and T-DXd showed marginal effect. Besides HER2 truncation, co-occurring EGFR and other receptor tyrosine kinase (RTK) amplification or overexpression can also lead to resistance to HER2-directed treatments. IAM1363 was tested in xenograft models using HER2-amplified/EGFR-high cell lines HCC1954 and SKOV3, and demonstrated robust TRs. Even more strikingly, IAM1363 led to TR in the HCC827 human lung cancer xenograft model with mid-level HER2, and high levels of EGFR and MET expression. The resistance combatting effect of IAM1363 goes beyond co-occurring RTK-mediated mechanism as IAM1363 also showed dose-dependent TR in KYSE410, a human esophageal squamous cancer xenograft model that harbors the KRAS G12C mutation and HER2 amplification. Taken together, IAM1363 represents a promising clinical candidate for the treatment of HER2-driven tumors. Its unique binding mechanism and potent pan-HER2 activity overcome multiple resistance mechanisms, and its strong EGFR avoidance widens the safety margin. Additionally, IAM1363 was found to be consistently enriched in xenograft tumors that had moderate to high HER2 expression levels, and those with HER2 activating mutations. This distinctive pharmacokinetic property facilitates optimal target engagement in tumors, including those occurring in the brain, while minimizing potential systemic side effects. Citation Format: Lana Kulyk, Kelly Chen, Iriny Botrous, Chunmei Zhao, Chang Zhao, Michael Maestre, Shawn Wright, Joseph Dennis, Jeeyoung Park, Abby Adams, Wallace Derricotte, Shane Yost, Mary L. Anderson, Fred Manby, Tom Miller, Chao Zhang, Laurent Gomez, Zhongdong Huang. Validation of a novel Type II HER2 inhibitor through preclinical studies across various cancer models [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 1980.

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

Abstract Introduction: Uncommon EGFR mutations in non-small cell lung cancer (NSCLC), including exon 20 insertion and atypical mutations, are generally associated with poorer clinical outcomes than common EGFR mutations. Patients (pts) with these mutations have limited effective therapeutic options. Afatinib is the only approved agent for uncommon mutations but is associated with high rates of toxicity and limited central nervous system (CNS) penetration. Amivantamab and mobocertinib are approved for patients with relapsed EGFR exon 20 insertion NSCLC but are associated with limitations in efficacy and CNS activity. BLU-451 is an investigational, CNS-penetrant, EGFR-wild-type (WT)–sparing, selective inhibitor against exon 20 insertion and uncommon EGFR mutations that is currently being evaluated in the phase 1/2 CONCERTO study (NCT05241873). Here, we report on the prevalence of uncommon EGFR mutations from a single center, real-world data set (MD Anderson Cancer Center [MDACC]), and report preclinical activity of BLU-451 on a broad spectrum of uncommon EGFR mutations by structure classification. Methods: BLU-451 cellular activity was evaluated in engineered BaF3 cell lines expressing 62 EGFR kinase domain mutations as well as in cell lines dependent on WT EGFR, using the CellTiter-Glo® Luminescent Cell Viability Assay and a phosphorylation-specific EGFR AlphaLISA® assay. The MDACC Moon Shot™ Genomic Marker-Guided Therapy Initiative (GEMINI) database was searched for pts with NSCLC whose tumors harbored EGFR kinase domain mutations. Results: In the MDACC GEMINI database, a total of 1495 unique patients with NSCLC harboring EGFR mutations were identified, including 1025 with classical mutations (exon 19 deletion and L858R) with or without T790M, 223 with exon 20 insertion mutations, and 247 with only atypical mutations. In BaF3 cells, BLU-451 demonstrated nanomolar potency in multiple atypical and exon 20 insertion mutation cell lines with selectivity against WT EGFR. Conclusion: Atypical EGFR mutations represent a sizable NSCLC pt population, of similar magnitude to that of EGFR exon 20 insertion mutations. BLU-451 preclinical data in EGFR atypical and exon 20 insertion mutations showed broad, potent, and selective activity, supporting continued evaluation of BLU-451 in the phase 1/2 CONCERTO study in pts with advanced or metastatic NSCLC harboring uncommon EGFR mutations. Citation Format: Xiuning Le, Yves Millet, Monique Nilsson, Aditya Dhande, Jeffrey Keats, Holly Ponichtera, Joseph Kim, Junqin He, Yasir Y. Elamin, John V. Heymach, Chiara Conti, Stephanie Lee. BLU-451 is a CNS-penetrant, wild-type-sparing EGFR inhibitor with broad coverage of uncommon EGFR mutations across structure-based subsets [abstract]. In: Proceedings of the AACR-NCI-EORTC Virtual International Conference on Molecular Targets and Cancer Therapeutics; 2023 Oct 11-15; Boston, MA. Philadelphia (PA): AACR; Mol Cancer Ther 2023;22(12 Suppl):Abstract nr C151.

Abstract B124: MYTX-011 is a highly internalized ADC with anti-tumor activity across a spectrum of NSCLC preclinical models with various levels of cMET expression

Abstract cMET overexpression occurs in non-small cell lung cancer (NSCLC) and antibody-drug conjugates targeting cMET (cMET-ADCs) have been developed to treat cMET+ NSCLC tumors irrespective of dependency on cMET signaling. cMET-ADCs have shown promising clinical activity, but largely in a subset of NSCLC patients whose tumors express the highest cMET levels. MYTX-011, an investigational, pH-sensitive ADC incorporating the clinically validated vcMMAE linker-payload, was specifically designed to potentially benefit a broader population of patients including those whose tumors express lower cMET levels. We’ve previously demonstrated that pH-sensitive cMET binding of MYTX-011 drives higher internalization in cMET+ tumor cells, and greater cytotoxicity against a panel of cMET+ cancer cell lines in vitro. MYTX-011 also shows superior efficacy in NSCLC xenograft models with high or moderate cMET expression levels when compared to the matched non-pH-sensitive Parent ADC or a Benchmark ADC generated by hinge conjugation of a clinical stage anti-cMET ADC antibody to vcMMAE. Here we demonstrate that the MYTX-011 monoclonal antibody, which is engineered to selectively and rapidly lose affinity at the acidic pH of endolysosomes, rapidly internalizes and accumulates in cells expressing moderate cMET levels compared to the matched parent antibody. MYTX-011 in vitro cytotoxicity correlated with cMET expression levels and conferred sensitivity to cells that were otherwise insensitive to ADCs generated with the parent or Benchmark antibodies. Importantly, cells that were only sensitive to MYTX-011, but not matched controls, expressed low and moderate levels of cMET. Furthermore, MYTX-011 was active against the low cMET-expressing NCI-H2122 xenograft model in vivo whereas the Benchmark ADC was inactive. In the moderate cMET-expressing NCI-H1975 xenograft model, MYTX-011 was more active than both the Benchmark ADC and a second benchmark ADC generated by hinge conjugation of a clinical stage biparatopic anti-cMET ADC antibody to a maytansinoid linker/toxin. MYTX-011 activity was further evaluated against a panel of NSCLC patient derived xenograft (PDX) models with relevant histology, cMET expression, and genetic profiles. MYTX-011 was highly active in cMET+ squamous and adenocarcinoma PDX, EGFR WT and mutant PDX, in a PDX model with MET ex14 skipping mutation, and in PDX with heterogenous cMET expression. Together, these findings highlight the potential of MYTX-011 as a therapeutic candidate for treating a broader range of cMET+ NSCLC malignancies than other cMET-ADCs. Citation Format: William C Comb, Deepak Kanojia, Federico Colombo, Vijay Ramesh, Nimish Gera, Thomas Chittenden, Brian Fiske. MYTX-011 is a highly internalized ADC with anti-tumor activity across a spectrum of NSCLC preclinical models with various levels of cMET expression [abstract]. In: Proceedings of the AACR-NCI-EORTC Virtual International Conference on Molecular Targets and Cancer Therapeutics; 2023 Oct 11-15; Boston, MA. Philadelphia (PA): AACR; Mol Cancer Ther 2023;22(12 Suppl):Abstract nr B124.

Abstract LB_C14: EAI-432: A mutant-selective allosteric EGFR inhibitor for L858R-mutant non-small cell lung cancer

Abstract While osimertinib is highly efficacious in lung cancers with sensitizing mutations in EGFR, there is a major unmet need for agents that overcome resistance to it and other covalent third-generation EGFR TKIs due to the C797S mutation. Furthermore, osimertinib extends overall survival in patients with exon19 deletions but offers little improvement in overall survival in patients with the L858R mutation relative to the first-generation inhibitors. We are developing EAI-432 with the goal of improving outcomes for patients with EGFRL858R+ lung cancer. EAI-432 is a mutant-selective allosteric inhibitor that is effective against L858R and its common resistance variants, L858R/T790M, L858R/C797S, and L858R/T790M/C797S while sparing WT EGFR. The compound induces tumor regressions in a L858R/T790M/C797S mouse xenograft model at low doses (5 mg/kg). In the H1975 (L858R/T790M) xenograft model, EAI-432 induced marked tumor regressions in both subcutaneous and intracranial implants. EAI-432 co-binds with osimertinib, allowing double-drugging of the mutant receptor. The distinct binding site and allosteric mechanism of EAI-432 are expected to confer exquisite kinome-wide selectivity and orthogonal resistance mechanisms as compared with osimertinib and other ATP-competitive TKIs, properties that are highly desirable in a combination agent. The compound has efficacy, mutant-selectivity, and pharmacokinetic properties including brain-penetrance that support its further development as a therapeutic agent for EGFRL858R+ lung cancer alone or in combination with osimertinib. Citation Format: Michael J. Eck, David A. Scott, Pasi Janne, Tyler S. Beyett, Jie Jiang, Praful Gokhale, Thomas W. Gero. EAI-432: A mutant-selective allosteric EGFR inhibitor for L858R-mutant non-small cell lung cancer [abstract]. In: Proceedings of the AACR-NCI-EORTC Virtual International Conference on Molecular Targets and Cancer Therapeutics; 2023 Oct 11-15; Boston, MA. Philadelphia (PA): AACR; Mol Cancer Ther 2023;22(12 Suppl):Abstract nr LB_C14.

Rational design and eco-friendly one-pot multicomponent synthesis of novel ethylidenehydrazineylthiazol-4(5H)-ones as potential apoptotic inducers targeting wild and mutant EGFR-TK in triple negative breast cancer

A novel series of ethylidenehydrazineylthiazol-4(5H)-ones were synthesized using various eco-friendly one-pot multicomponent synthetic techniques. The anticancer activity of compounds (4a-m) was tested against 11 cancer cell lines. While the IC50 of all compounds was evaluated against the most sensitive cell lines (MDA-MB-468 and FaDu). Our SAR study pinpointed that compound 4a, having a phenyl substituent, exhibited a significant growth inhibition % against all cancer cell lines. The frontier anticancer candidates against the MDA-MB-468 were also examined against the wild EGFR (EGFR-WT) and mutant EGFR (EGFR-T790M) receptors. Most of the synthesized compounds exhibited a higher inhibitory potential against EGFR-T790M than the wild type of EGFR. Remarkably, compound 4k exhibited the highest inhibitory activity against both EGFR-WT and EGFR-T790M with IC50 values (0.051 and 0.021 µM), respectively. The pro-apoptotic protein markers (p53, BAX, caspase 3, caspase 6, caspase 8, and caspase 9) and the anti-apoptotic key marker (BCL-2) were also measured to propose a mechanism of action for the compound 4k as an apoptotic inducer for MDA-MB-468. Investigation of the cell cycle arrest potential of compound 4k was also conducted on MDA-MB-468 cancer cells. We also evaluated the inhibitory activities of compounds (4a-m) against both EGFR-WT and EGFR-T790M using two different molecular docking processes.

NSCLC presents metabolic heterogeneity, and there is still some leeway for EGF stimuli in EGFR-mutated NSCLC

BackgroundMetabolic remodeling is crucial in carcinogenesis and cancer progression. Oncogenic mutations may promote metabolic reprogramming in cancer cells to support their energy and biomass requirements. EGFR mutations are commonly found in non-small cell lung cancer (NSCLC) and may induce NSCLC metabolic rewiring. Whether EGFR-driven metabolic reprogramming triggers cell vulnerabilities with therapeutic potential remains unknown. MethodsThe role of EGFR signaling activation by EGF was investigated using NSCLC cell lines with different EGFR and KRAS status: A549 (EGFR WT and KRAS c.34G > A), H292 (EGFR WT and KRAS WT) and PC-9 (EGFR exon 19 E746-A750 deletion and KRAS WT). The effect of EGF on NSCLC cell death and cell cycle was evaluated using flow cytometry, and cell migration was assessed through wound healing. EGFR, HER2, MCT1, and MCT4 expression was analyzed through immunofluorescence or western blotting. We explored the impact of glucose and lactate bioavailability on NSCLC cells' metabolic profile using nuclear magnetic resonance (NMR) spectroscopy. Moreover, the expression of several relevant metabolic genes in NSCLC cells or patient samples was determined by RT-qPCR. ResultsWe showed that cell lines presented different metabolic profiles, and PC-9 cells were the most responsive to EGF stimulus, as they showed higher rates of cell proliferation and migration, together with altered metabolic behavior. By inhibiting EGFR with gefitinib, a decrease in glucose consumption was observed, which may be related to the fact that despite PC-9 harbor EGFR mutation, they still express the EGFR WT allele. The analysis of NSCLC patients' RNA showed a correlation between MCT1/MCT4 and GLUT1 expression in most cases, indicating that the metabolic information can serve as a reference in patients' follow-up. ConclusionTogether, this study shows that NSCLC cell lines have heterogeneous metabolic profiles, which may be underlaid by different genetic profiles, revealing an opportunity to identify and stratify patients who can benefit from metabolism-targeted therapies.

Deciphering the molecular mechanism of enhanced tumor activity of the EGFR variant T790M/L858R using melanoma cell lines.

The abnormal expression and mutagenesis of EGFR drives both the development and progression of a multitude of human cancers. Further mutations within the tyrosine kinase region of the EGFR subsequently contribute to resistance to targeted drugs. What is not known is how these mutations affect progression-related behaviors of cancer cells. The mutagenesis of EGFR T790M, L858R, and T790M/L858R was performed via oligo primer-guided polymerase chain reaction (PCR). GFP-tagged mammalian expression vectors were constructed and confirmed. Stable melanoma cell lines WM983A and WM983B expressing WT or mutant EGFRs were generated for determining the functions of WT and mutant EGFRs in migration, invasion, and resistance to doxorubicin. Immunoblotting and immunofluorescence were performed to detect the transphosphorylation and autophosphorylation of WT and mutant EGFRs and other molecules. The EGFR mutant T790M/L858R showed significantly higher basal autophosphorylation in melanoma cell lines WM983A and WM983B. Overexpression of WT EGFR significantly enhanced the protein level of E-cadherin (E-cad) via upregulating its mRNA. In contrast, L858R significantly downregulated E-cad. Biological activity assays show that T790M/L858R presented significant enhancement in vitro in invasion and migration, while WT and T790M moderately inhibited invasion and migration. In WM983A cells, enhanced invasion and migration by T790M/L858R required the downstream signaling pathways through Akt and p38. T790M/L858R dramatically triggers phosphorylation of actin cross-linking protein alpha-actinin-4 in the absence of EGF. This double mutant also conferred resistance to a general chemotherapy doxorubicin through Akt but not the p38 signaling pathway. These findings suggest that T790M/L858R not only confers enhanced therapeutic resistance in cancer cell lines but also may promote tumor metastasis via its boosted downstream signaling pathways and/or direct phosphorylation of other key proteins.

Evaluation of the prevalence of MET and protein tyrosine kinase 7 expression in non-small cell lung cancer to evaluate overlap of ADC antigens.

e21105 Background: Biomarker-targeted antibody-drug conjugates (ADCs) have shown promise in treating lung cancer. Telisotuzumab vedotin (Teliso-V; ABBV-399) is a first-in-class MET (also known as c-Met)-directed ADC comprising the monoclonal antibody telisotuzumab (ABT-700) conjugated to a cytotoxic microtubule inhibitor, monomethyl auristatin E (MMAE), via a cleavable dipeptide linker. In the phase 2 LUMINOSITY study (NCT03539536), Teliso-V demonstrated promising anticancer activity in previously treated patients with MET-overexpressing (OE), non-squamous epidermal growth factor receptor wild type ( EGFR WT) non-small cell lung cancer (NSCLC; 52.2% overall response rate in MET OE high group, 36.5% in all MET OE cohort [intermediate and high]) and an acceptable safety profile (Camidge et al. J Clin Oncol. 2022;40:16 suppl, 9016). These data provide proof of concept that biomarker-selected MMAE-based ADCs could be beneficial to patients with NSCLC. Cofetuzumab pelidotin (ABBV-647), an ADC with a similar composition to Teliso-V, contains an anti-protein tyrosine kinase 7 (PTK7) monoclonal antibody (hu6MO24) conjugated to a microtubule-inhibiting cytotoxin, Aur0101 auristatin, via a cleavable cysteine-reactive linker. PTK7 expression and oncogenic functions have been reported in several cancers. We sought to establish the co-prevalence of MET OE and PTK7 in NSCLC to understand if both these antigens targeted by ADCs are co-expressed or present in distinct tumors. Methods: Antigen prevalence was analyzed in tumor samples from patients at the City of Hope National Medical Center with non-squamous NSCLC and EGFR WT or unknown status. Immunohistochemistry (IHC) assays used were MET (SP44) Assay for MET OE (Roche Tissue Diagnostics; positive if ≥25% cells at 3+ intensity) and an AbbVie-developed assay for PTK7 expression (positive if ≥90% cells at ≥2+ intensity). Results: A total of 148 patients (median age 67 years, 52% stage ≥III at diagnosis, 68% ECOG 0–2) were screened (data shown in table). About 24% of the patients were MET IHC positive, whereas 11% were PTK7 IHC positive. Further, MET OE and PTK7 had complementary prevalence with only 3% of the patients co-expressing both antigens. Conclusions: MET OE and PTK7 expression by IHC were found to be complementary in patients with non-squamous EGFR WT/unknown NSCLC. About 32% of patients were positive for MET OE or PTK7 expression or both. Data represent patients from a single center and more pre-treatment tissue samples that were viable and available. These IHC findings suggest that MET OE and PTK7 are indeed complementary NSCLC biomarkers. [Table: see text]

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

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

Pharmacokinetic Profile Evaluation of Novel Combretastatin Derivative, LASSBio-1920, as a Promising Colorectal Anticancer Agent.

LASSBio-1920 was synthesized due to the poor solubility of its natural precursor, combretastatin A4 (CA4). The cytotoxic potential of the compound against human colorectal cancer cells (HCT-116) and non-small cell lung cancer cells (PC-9) was evaluated, yielding IC50 values of 0.06 and 0.07 μM, respectively. Its mechanism of action was analyzed by microscopy and flow cytometry, where LASSBio-1920 was found to induce apoptosis. Molecular docking simulations and the enzymatic inhibition study with wild-type (wt) EGFR indicated enzyme-substrate interactions similar to other tyrosine kinase inhibitors. We suggest that LASSBio-1920 is metabolized by O-demethylation and NADPH generation. LASSBio-1920 demonstrated excellent absorption in the gastrointestinal tract and high central nervous system (CNS) permeability. The pharmacokinetic parameters obtained by predictions indicated that the compound presents zero-order kinetics and, in a human module simulation, accumulates in the liver, heart, gut, and spleen. The pharmacokinetic parameters obtained will serve as the basis to initiate in vivo studies regarding LASSBio-1920's antitumor potential.

Abstract 1440: Identification of a novel EGFR sparing brain penetrant ErbB2 inhibitor with activity against oncogenic ErbB2 mutations

Abstract Oncogenic driver mutations in ErbB2 (e.g., S310F/Y, L755S, V777L, V842I) are present in a variety of tumor types including gastric, uterine, urothelial carcinoma, non-small cell lung, breast, and colorectal, some of which are also known to metastasize to the CNS. These mutations can also emerge as mechanisms of acquired resistance to targeted therapies and as such represent a novel and actionable target mutation set across solid tumor indications. Current therapies that target ErbB2 have poor potency against these mutations or are limited in their utility due to inhibition of wild type epidermal growth factor receptors (WT EGFR). The inhibition of WT EGFR is associated with debilitating clinical effects that include diarrhea, stomatitis, and hepatotoxicity. Additionally, treatment of CNS metastases is especially challenging since the potential therapy must also cross the blood brain barrier to have a therapeutic effect. Next generation ErbB2 inhibitors that are active against ErbB2 mutations, spare WT EGFR, and that can penetrate the brain would provide improved target coverage with the potential for fewer off target side effects compared to current therapies and as well as the potential to exhibit superior clinical efficacy. Herein, we describe the pre-clinical in vitro and in vivo activity of a novel, brain penetrant ErbB2 inhibitor which retains potency against prevalent mutations while sparing WT EGFR. Citation Format: Mark J Chicarelli, Karyn Bouhana, Richard K. Brizendine, LouAnn Cable, Michelle Crow, Brad Fell, John Fischer, Jennifer Fulton, Anna Guarnieri, Ravi Jalluri, Hailey Knox, Keith A. Koch, Rob Rieger, John Robinson, Lee M. Stunkard, Francis Sullivan, Roy Turton, Shannon Winski, Yeyun Zhou. Identification of a novel EGFR sparing brain penetrant ErbB2 inhibitor with activity against oncogenic ErbB2 mutations [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 1440.

Abstract 5935: Phenotype profiling of tumor microenvironment in EGFR mutant lung adenocarcinoma with multi-omics data

Abstract Introduction: EGFR mutations holds the major targets for drug in lung adenocarcinoma (LUAD). Despite the tremendous study of EGFR mutant (MT) LUAD, the comprehensive interpretation of the heterogeneous character of LUAD harboring EGFR MT remains a key challenge. Here, we investigated the heterogeneity of EGFR MT LUAD and explored the tumor microenvironment (TME) in EGFR MT LUAD. Method: We performed single-cell RNA sequencing (scRNA-seq) from 135 LUAD patients which consist of normal(n=24), EGFR wild (WT)(n=18), and MT(n=93). Also, we used whole genome sequencing and bulk-RNA sequencing to validate with scRNA-seq results. From 898,648 cells, main cell types were classified. To explore the various characteristics of MT LUAD tumor cells, we used two ways: i) We re-clustered epithelial cells populating the normal, WT, and MT. ii) We re-clustered only MT epithelial cells. In each analysis, we identified the tumor character in the clusters using differential expressed genes analysis, lineage tracing, clinical information, mutation, and trajectory analysis. Also, we extracted each main cell type except epithelial cells, and identified subtypes of main cell types. Finally, we revealed the interaction of cellular components in TME. Results: In the analysis of epithelial cells, we identified characteristics of specific EGFR MT by comparing of EGFR WT and MT tumors in clusters with similar biological features. The cluster represented by alveolar type 2 (AT2) known as initiation of LUAD was populating normal, WT, and MT. In this cluster, MT- and WT-associated pathway shared but differently significant between MT and WT in the pathway analysis. The cluster represented by proliferative is mostly comprised tumor cells and we found significantly increased the expression of MDK, CD24 in the MT of the cluster. In the analysis of only MT epithelial cells, 2 of clusters were stage-specific cluster: i) The cluster annotated as early stage cluster, ii) The cluster annotated as advanced stage cluster. Trajectory showed that there is a pseudotemporal continuum, following the stage from early stage cluster to advanced stage cluster. Also, based on the lineage tracing, 2 of clusters revealed lineage-specific clusters: i) The cluster annotated as AT2 was enriched from early stage cells, ii) The cluster annotated as basal cell known as origin of lung squamous cell carcinoma(LUSC) was enriched from advanced stage cells. Psedotemporal ordering of these cluster revealed AT2 cluster transdifferentiate into basal cell cluster which implied the possibility of LUAD to LUSC transition by drug resistance. In the interaction of MT and WT TME, the number of signaling received epithelial cells from myeloid cells, endothelial cells, and fibroblasts as sender increased compared with the interaction of normal. Conclusion: We shed light on the ecosystem of TME according to clinical and biological feature of tumor in EGFR mutant LUAD. Citation Format: You Won Lee, Eun Ji Lee, Seung Yeon Oh, Kyoung-Ho Pyo, Seong Gu Heo, YoungJoon Park, Su-Jin Choi, Kyumin Lim, Ju-hyeon Lee, Jae Hwan Kim, Jii Bum Lee, Ji Yoon Lee, Sun Min Lim, Chang Gon Kim, Min Hee Hong, Mi Ran Yun, Byoung Chul Cho. Phenotype profiling of tumor microenvironment in EGFR mutant lung adenocarcinoma with multi-omics data. [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 5935.

Identification of a novel peptide ligand for the cancer-specific receptor mutation EGFRvIII using high-throughput sequencing of phage-selected peptides

We report here the selection and characterization of a novel peptide ligand using phage display targeted against the cancer-specific epidermal growth factor tyrosine kinase receptor mutation variant III (EGFRvIII). This receptor is expressed in several kinds of cancer: ovarian cancer, breast cancer and glioblastoma, but not in normal tissues. A 12-mer random peptide library was screened against EGFRvIII. Phage-selected peptides were sequenced in high-throughput by next generation sequencing (NGS), and their diversity was studied to identify highly abundant clones expected to bind with the highest affinities to EGFRvIII. The enriched peptides were characterized and their binding capacity towards stable cell lines expressing EGFRvIII, EGFR wild type (EGFR WT), or a low endogenous level of EGFR WT was confirmed by flow cytometry analysis. The best peptide candidate, VLGREEWSTSYW, was synthesized, and its binding specificity towards EGFRvIII was validated in vitro. Additionally, computational docking analysis suggested that the identified peptide binds selectively to EGFRvIII. The novel VLGREEWSTSYW peptide is thus a promising EGFRvIII-targeting agent for future applications in cancer diagnosis and therapy.

Structural Basis for Inhibition of Mutant EGFR with Lazertinib (YH25448).

Lazertinib (YH25448) is a novel third-generation tyrosine kinase inhibitor (TKI) developed as a treatment for EGFR mutant non-small cell lung cancer. To better understand the nature of lazertinib inhibition, we determined crystal structures of lazertinib in complex with both WT and mutant EGFR and compared its binding mode to that of structurally related EGFR TKIs. We observe that lazertinib binds EGFR with a distinctive pyrazole moiety enabling hydrogen bonds and van der Waals interactions facilitated through hydrophilic amine and hydrophobic phenyl groups, respectively. Biochemical assays and cell studies confirm that lazertinib effectively targets EGFR(L858R/T790M) and to a lesser extent HER2. The molecular basis for lazertinib inhibition of EGFR reported here highlights previously unexplored binding interactions leading to improved medicinal chemistry properties compared to clinically approved osimertinib (AZD9291) and offers novel strategies for structure-guided design of tyrosine kinase inhibitors.

388P Capmatinib in Chinese adults with EGFR wt, ALK rearrangement negative (ALK-R−), MET exon 14 skipping mutation (METex14), advanced NSCLC: Results from the phase II GEOMETRY-C study

To date, there is no approved targeted therapy for treatment-naive patients (pts) with METex14 NSCLC in China. Capmatinib, a selective MET inhibitor (METi), is approved for use in this population in >40 countries worldwide, including the US and EU. We report the efficacy and safety of capmatinib as monotherapy in treatment-naive Chinese pts with MET-mutated, advanced NSCLC.