EGFR-targeted Antibodies Research Articles

Fluidic Interface for Surface-based DNA Origami Studies.

Traditionally, the use of DNA origami nanostructures (DONs) to study early cell signaling processes has been conducted using standard laboratory equipment with DONs typically utilized in solution. Surface-based technologies simplify the microscopic analysis of cells treated with DON agents by anchoring them to solid substrates, thus avoiding the complications of receptor-mediated endocytosis. A robust microfluidic platform for real-time monitoring and precise functionalization of surfaces with DONs was developed here. The combination of controlled flow conditions with an upright total internal reflection fluorescence microscope enabled the kinetic analysis of the immobilization of DONs on DNA-functionalized surfaces. The results revealed that DON morphology and binding tags influence the binding kinetics and that DON hybridization on surfaces is more effective in microfluidic devices with larger-than-standard dimensions, addressing the low diffusivity challenge of DONs. The platform enabled the decoration of DONs with protein-binding ligands and in situ investigation of ligand occupancy on DONs to produce high-quality bioactive surfaces. These surfaces were used to recruit and activate the epidermal growth factor receptor (EGFR) through clustering in the membranes of living cancer cells (MCF-7) using an antagonistic antibody (Panitumumab). The activation was quantified depending on the interligand distances of the EGFR-targeting antibody.

Amivantamab plus chemotherapy vs chemotherapy as first-line treatment among patients with EGFR exon 20 insertion–mutated advanced non-small cell lung cancer (NSCLC): PAPILLON Chinese subgroup analysis.

8606 Background: Amivantamab (Ami) is a bispecific antibody targeting EGFR and MET tyrosine kinase receptors with immune cell-directing activity. The phase 3 PAPILLON study (NCT04538664) investigated the combination of Ami and carboplatin/pemetrexed (ACP) vs. carboplatin/pemetrexed (CP) as first-line treatment in patients (pts) with advanced EGFR Exon20ins-mutated NSCLC. ACP improved progression free survival (PFS) in both the overall population and Asian subgroup. Methods: Pts were randomized 1:1 to ACP or CP. The primary endpoint was PFS by blinded independent central review (BICR) and key secondary endpoints included objective response rate (ORR), PFS after first subsequent therapy (PFS2), overall survival (OS), and safety. Crossover to Ami monotherapy was allowed for pts in CP arm following disease progression. Results: Among the 308 pts enrolled, 87 were Chinese, with 39 receiving ACP and 48 receiving CP. Median age was 57/57 years, 46%/63% were female, and 15%/25% history of brain metastases for pts in ACP/CP arms. Baseline characteristics were generally balanced between arms. After a median follow-up of 16.4 months (mo), median PFS was 12.3 mo (95% CI: 7.00, NE) in ACP arm compared with 6.7 mo (95% CI: 4.21, 8.57) in CP arm (hazard ratio [HR], 0.47; 95% CI, 0.26-0.85; P = 0.011) (Table). ORR was 71.8% (95% CI, 55.1%-85.0%) for ACP, and 48.9% (95% CI, 34.1%–63.9%) for CP (odds ratio, 2.46; 95% CI, 1.01-5.98; P = 0.048). Median PFS2 was not estimable (NE) for ACP vs 18.8 mo for CP (HR, 0.32; 95% CI, 0.11-0.88; P = 0.021). Interim OS showed a favorable trend for ACP vs CP (HR, 0.58; 95% CI: 0.17-2.02; P = 0.387) despite crossover among CP-randomized pts (n = 24, 50%) who had progressed. Most common AEs (all grades) ( > 50%) in ACP arm were rash, paronychia, hypoalbuminemia, neutropenia, anemia, leukopenia and thrombocytopenia which were consistent with the known safety profile of the individual agents. Notably, no pts had discontinuation of Ami due to an AE. Conclusions: ACP demonstrated superior PFS compared to CP in Chinese pts. The safety profile was manageable and tolerable. These findings in Chinese subgroup were consistent with those of overall population and Asian subgroup. Clinical trial information: NCT04538664 . [Table: see text]

Efficacy and safety of MCLA-129, an EGFR/c-MET bispecific antibody, in advanced non-small cell lung cancer (NSCLC).

8604 Background: MCLA-129 is a common light chain, Biclonics, bispecific antibody targeting EGFR and c-MET with enhanced antibody-dependent cellular cytotoxicity. Here we describe the ongoing first-in-human phase 1/2 study of MCLA-129 in patients with NSCLC, including patients with MET exon 14 skipping (METex14) mutation (cohort A), EGFR exon 20 insertion (exon20ins)-mutated (cohort B) and sensitized EGFR-mutated disease (cohort C). Methods: Patients received MCLA-129 (100–2000 mg) IV biweekly or 1000-1500 mg IV weekly in a 28-day cycle in dose escalation. Doses at 1500 and 2000 mg IV biweekly are being explored in dose expansion. The primary endpoint was safety and tolerability. Objective response rate by investigator assessment per RECIST v1.1 of patients with NSCLC treated at 1500 and 2000 mg IV biweekly in three cohorts is reported. Results: As of 26 May 2023, 217 enrolled patients received MCLA-129 in China. The data cut-off was 24 Nov 2023. The most common treatment-emergent adverse events (TEAEs) were infusion related reaction (71.9%), hypoalbuminemia (54.8%), decreased neutrophil count (46.1%), and decreased white blood cell count (40.1%). TEAEs mostly were grade 1-2. Grade ≥3 TEAEs and drug-related TEAEs were reported in 51.6% and 39.2% of patients, respectively. 176 of the 215 NSCLC patients were evaluable. The confirmed objective response rates (ORR) in Cohort A, B and C were 43.5%, 28.6% and 21.8%, respectively. Especially, for patients in Cohort A receive prior MET TKI, the ORR was 37.5% and disease control rate (DCR) was 93.8%. Overall efficacy is shown (Table). Conclusions: MCLA-129 demonstrates robust and durable antitumor activity in patients with NSCLC harboring METex14, EGFR exon20ins and sensitized EGFR mutations, with a manageable safety profile; enrollment in dose expansion is ongoing. Clinical trial information: NCT04930432 . [Table: see text]

A real-world pharmacovigilance study of amivantamab-related cardiovascular adverse events based on the FDA adverse event reporting system (FAERS) database

Amivantamab is the first dual-specificity antibody targeting EGFR and MET, which is approved for the treatment of locally advanced or metastatic non-small cell lung cancer (NSCLC) with EGFR exon 20 insertion mutations. Cardiovascular toxicities related to amivantamab have not been reported in the CHRYSALIS study. However, the occurrence of cardiovascular events in the real world is unknown. To comprehensively investigate the clinical characteristics, onset times, and outcomes of cardiovascular toxicities associated with amivantamab. The Food and Drug Administration Adverse Event Reporting System (FAERS) database from 1st quarter of 2019 to the 2nd quarter of 2023 was retrospectively queried to extract reports of cardiovascular adverse events (AEs) associated with amivantamab. To perform disproportionality analysis, the reporting odds ratios (RORs) and information components (ICs) were calculated with statistical shrinkage trans-formation formulas and a lower limit of the 95% confidence interval (CI) for ROR (ROR025) > 1 or IC (IC025) > 0 with at least 3 reports was considered statistically significant. A total of 20,270,918 eligible records were identified, among which 98 records were related to cardiovascular events associated with amivantamab. 4 categories of cardiovascular events exhibited positive signals: venous thrombotic diseases, abnormal blood pressure, arrhythmia, and pericardial effusion. Venous thrombotic diseases and abnormal blood pressure were the two most common signals. The median time to onset (TTO) for cardiovascular AEs was 33 days. The cumulative incidence within 90 days was 100% for cardiac failure, 75% for stroke, 63.16% for arrhythmia, 50% for sudden death, and 44.18% for venous thrombotic diseases. Death accounted for 16.3% of all cardiovascular AEs associated with amivantamab. The mortality rates for Major Adverse Cardiovascular Events (MACE) were up to 60%. This pharmacovigilance study systematically explored the cardiovascular adverse events of amivantamab and provided new safety signals based on past safety information. Early and intensified monitoring is crucial, and attention should be directed towards high-risk signals.

Enabling multi-modal imaging and photoimmunotherapy of oral cancer spheroids through an EGFR-targeted antibody conjugate

SignificanceDelineating tumor margins during surgery and eliminating residual disease is a major challenge in the treatment of oral cancers. The dual function antibody conjugate (DFAC) developed in this study can enable 3D-imaging and destroy residual microscopic disease by photoimmunotherapy in a single intra-operative setting. ApproachDFAC was synthesized by routine carbodiimide crosslinker chemistry. Multi-modal imaging (Photoacoustic and fluorescence imaging) and photoimmunotherapy was performed on oral cancer spheroids. ResultsPhotoacoustic imaging could detect tumor spheroids, even of the smallest size (0.01 mm3), while fluorescence imaging could detect only larger spheroids with volumes greater than 0.049 mm3 and treated with a higher DFAC concentration. Photoimmunotherapy showed a spheroid size dependent response, with smaller spheroids of volumes 0.018 mm3 and lower showing no recurrence. ConclusionsThe complementary imaging and treatment capabilities of DFAC could help in minimizing healthy tissue resection and enhance recurrence free survival in oral cancer patients.

Abstract 1892: KK2260: A fully human tetravalent bispecific antibody targeting TfR1 and EGFR for the treatment of EGFR-expressing tumors

Abstract Background: TfR1 is a transmembrane glycoprotein involved in iron uptake and regulation of cell growth. High TfR1 expression has been reported in different types of cancers, therefore recognized as a target molecule for cancer therapy. Despite the promise of potent efficacy of TfR1-targeted agents, there is a risk of side effects (i.e., severe anemia), since TfR1 is also highly expressed in certain normal cells (e.g., reticulocytes). KK2260 is a fully human tetravalent bispecific antibody (bsAb) based on REGULGENTTM technology targeting TfR1 and EGFR. This bsAb was designed for EGFR-expressing cell selective anti-cancer drug which could not be achieved by conventional monospecific Ab. In this study, we evaluated the mechanism of action (MOA), anti-cancer effect, and toxicity of KK2260. Methods: Binding activity of KK2260 to TfR1 and EGFR was evaluated by surface plasmon resonance method. Ligand blocking activity was evaluated by binding competition on esophageal squamous cell carcinoma (ESCC) OE21 cells. Growth inhibitory activity of KK2260 on cancer cells or hematopoietic progenitor cells was evaluated by proliferation inhibition assay. In some studies, excessive iron or anti-EGFR parent Ab was added. Effect on the cell surface target expression levels was evaluated by flow cytometry. The intracellular iron level was evaluated by cell imaging. Effect on EGF induced EGFR phosphorylation was evaluated by Western blotting. The in vivo efficacy of KK2260 was evaluated in cell line-derived and patient-derived xenograft (PDX) models of ESCC selected for high EGFR expression level. The toxicity of KK2260 was evaluated in cynomolgus monkeys. Results: KK2260 bound to TfR1 and EGFR with no ligand binding inhibition. KK2260 inhibited cell growth of moderate to high EGFR-expressing cancer cells, but not against EGFR-negative cancer cells or hematopoietic progenitor cells. KK2260 downregulated TfR1 expression on OE21 cells and the intracellular iron level decreased, but no effect was observed on EGFR phosphorylation. The growth inhibitory activity of KK2260 was abolished by adding excessive amounts of iron or reduced by inhibiting the binding to EGFR. Potent anti-tumor activity was observed in the ESCC PDX models with tumor regression. In the intermittent-dose toxicity study of cynomolgus monkeys, KK2260 was well-tolerated. Conclusions: KK2260 demonstrated potent anti-cancer effect both in vitro and in vivo. Intriguingly, KK2260 did not inhibit EGFR phosphorylation while EGFR-binding dependent TfR1 downregulation resulted in intracellular iron deficiency, which was considered as the MOA of KK2260. KK2260 was well tolerated in non-human primates. These preclinical data suggest the unique property of KK2260 is expected to provide significant benefit to patients with advanced ESCC and other EGFR-expressing tumors and Phase 1 study is currently on going in Japan (jRCT2031230372). Citation Format: Keisuke Mitamura, Hironori Otsuki, Keiko Nakahashi, Ayaka Kitagawa, Masayo Kamigaki, Yohei Kurio, Miho Inoue, Yasunori Uemura. KK2260: A fully human tetravalent bispecific antibody targeting TfR1 and EGFR for the treatment of EGFR-expressing tumors [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 1892.

Abstract 4553: DXC004A, a novel EGFR antibody-tubulysin analog conjugate demonstrated potential to broaden therapeutic opportunities for non-small cell lung cancer

Abstract EGFR is a member of the epidermal growth factor receptor (HER) family, and the over-expression of EGFR plays an important role in the growth and progression of various tumors, including non-small cell lung cancer. Monoclonal EGFR antibodies, such as cetuximab and panitumumab, have proven efficacy in various types of cancer. However, treatment with the anti-EGFR agents can be associated with toxicities of the skin, nails, hair, and eyes. Nimotuzumab (Nimo) is the first humanized monoclonal antibody targeting EGFR and has been granted approval for use in squamous cell carcinoma of head and neck (SCCHN), glioma and nasopharyngeal cancer in different countries. In contrast to cetuximab, Nimotuzumab is distinguished by achieving higher or similar complete remission rate (CRR) or overall remission rate (ORR) of the primary tumor in clinical applications but much less toxicity, resulting in a better safety profile, which has been attributed to its about 10-fold lower affinity. Paclitaxel combined with cisplatin is the first-line chemotherapy regimen for non-small cell lung cancer. A phase 2 clinical trial has confirmed that Nimotuzumab combined with concurrent chemoradiation therapy (radiation concurrent with docetaxel and cisplatin, CCRT) was well tolerated for locally advanced squamous cell lung cancer. However, the combination strategy of Nimo-CCRT has only demonstrated similar OS and PFS to those in the CCRT group. DXC004A is an ADC drug targeting EGFR, in which a Nimotuzumab derivative and a Tubulysin B analog is conjugated by a functional linker. DXC004A is in phase I clinical trial and has demonstrated clinical activity in advanced non-small cell lung cancers and good tolerability. In vitro and in vivo results had confirmed that DXC004A monotherapy had better anti-tumor activity than the combination of Nimotuzumab and Tubulysin analog in HCC827 cell lines with high EGFR expression. Meanwhile, a single injection of low-dose DXC004 (2.5 mg/kg) in HCC827 xenograft model showed very good durable anti-tumor effect. Moreover, the combination of DXC004A with Cisplatin exhibited significantly better activities than that of Nimo-CCRT combination, DXC004A or cisplatin alone, in vitro and in vivo, which might solve the predicament of poor efficacy of Nimo-CCRT combination therapy. This synergy results suggested that DXC004A plus cisplatin would possibly be a new adjuvant therapy for non-small cell lung cancer in further clinical studies. Citation Format: Xiaobo Cai, Min Cao, Huihui Guo, Qingliang Yang, Yongxiang Chen, Xiangfei Kong, Yong Du, Zhicang Ye, Zhixiang Guo, Lingli Zhang, Lu Bai, Junxiang Jia, Yunxia Zheng, Wei Zheng, Jun Zheng, Wenjun Li, Yuanyuan Huang, Zhongliang Fan, Binbin Chen, Meng Dai, Robert Y. Zhao. DXC004A, a novel EGFR antibody-tubulysin analog conjugate demonstrated potential to broaden therapeutic opportunities for 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 4553.

Abstract 4084: Potent anti-tumor activity of ABN202 (anti-EGFR antibody-interferon-beta mutein) through direct cytotoxicity and indirect immune activation against non-small cell lung cancer, regardless of EGFR mutation status

Abstract Epidermal growth factor receptor (EGFR) is overexpressed or mutated in many patients with non-small cell lung cancer (NSCLC). Targeting EGFR mutation by tyrosine kinase inhibitors (TKIs) has significantly improved overall survival (OS) in patients with EGFR mutations. However, many patients experience tumor recurrence due to various resistance mechanisms. Therefore, there is an unmet medical need for new treatment strategies for patients with EGFR-positive NSCLC, regardless of EGFR mutation status. ABN202 is an antibody-cytokine fusion protein (ACFP) that serves as a platform technology compromising the IFN-β mutein (ABN102) fused to various antibodies for specific tumor targeting. In a previous study, we designed ABN202 (αEGFR) to comprise an EGFR targeting antibody (Cetuximab) and IFN-β mutein (ABN102) and we confirmed anti-cancer activities of ABN202 against EGFR-positive NSCLC. In this study, the direct cytotoxicity of ABN202 (αEGFR) was evaluated in human NSCLC cell lines with various driving mutations and EGFR expression levels. The indirect immune activation was tested in human peripheral blood mononuclear cells (PBMCs) and human IFNAR1/2 knock-in (KI) mice. The in vivo efficacy was evaluated in human NSCLC xenograft mouse models and human IFNAR1/2 KI mouse models. ABN202 (αEGFR) demonstrates potent anti-tumor activity through direct cytotoxicity and indirect immune activation in NSCLC, regardless of EGFR mutation status. Taken together, we suggest that ABN202 (αEGFR) is a promising drug candidate against NSCLC, regardless of EGFR mutation status. Citation Format: Hee Geon Park, Sung Hun Cho, Ha Yeon Park, Mi Gyoung Jo, Ji Hyun Park, Myeung Ryun Seo, Ji Hyun Kim, Sung Youl Hong, Kyoung Song, Chan Gyu Lee, Hae Min Jeong, Sae Hyung Lee, Na Young Kim, Jun Young Choi, Young Kee Shin. Potent anti-tumor activity of ABN202 (anti-EGFR antibody-interferon-beta mutein) through direct cytotoxicity and indirect immune activation against non-small cell lung cancer, regardless of EGFR mutation status [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 4084.

Abstract A033: Nuclear EGFR as a regulator of the tumor microenvironment

Abstract Overexpression of the Epidermal Growth Factor Receptor (EGFR) is observed in all subtypes of breast cancer and is associated with large tumor size, poor differentiation, and poor clinical outcomes. However, the role of EGFR in driving the disease remains unclear, as EGFR-targeted antibodies and tyrosine kinase inhibitors fail to work effectively in breast cancer patients with EGFR overexpression. A possible explanation for therapeutic resistance is the role of intracellular EGFR, where retrograde trafficking of EGFR to the nucleus results in EGFR functioning directly as a transcriptional cofactor, regulating the expression of genes that promote tumor growth, metastasis, and an immune suppressive microenvironment. Our goal is to understand how targeting nuclear EGFR impacts this microenvironment. Using a novel therapeutic peptide (cSNX1.3) that targets retrograde trafficking of EGFR, we discovered that inhibiting retro-translocation of EGFR elicited an immune response as demonstrated by the secretion of inflammatory cytokines. Using RNA-Seq analysis, we detected an increase in the expression of cytokine receptors and natural killer (NK) cell ligands, such as RAET1 and AICL. We demonstrated that this active immune microenvironment is not observed when we treat with the EGFR kinase inhibitor Erlotinib, indicating a nuclear EGFR-specific outcome. Studies from tumor-bearing WAP-TGFα transgenic mice (an EGFR-dependent model of breast cancer) found the presence of NK cells and the expression of their activating ligands and receptors, IL-33 and SLAM7, respectively, in the tumor microenvironment. We hypothesize that nuclear EGFR is suppressing the expression of inflammatory cytokines, receptors, and ligands important for activation and recruitment of NK cells, thereby allowing immune evasion and ultimately progression of the disease. Future studies will investigate the potential to combine nuclear EGFR inhibitors with immunotherapies to activate the tumor immune microenvironment and promote optimal therapeutic efficacy. Citation Format: Angelica Escoto. Nuclear EGFR as a regulator of the tumor microenvironment [abstract]. In: Proceedings of the AACR Special Conference in Cancer Research: Advances in Breast Cancer Research; 2023 Oct 19-22; San Diego, California. Philadelphia (PA): AACR; Cancer Res 2024;84(3 Suppl_1):Abstract nr A033.

Biomarkers for monoclonal antibody targeting EGFR in NSCLC: Challenges, current status, and future perspectives

Targeting EGFR has a long history in the treatment of non-small cell lung cancer (NSCLC). It was around the 2000s that it was reported that EGFR protein expression increased with bronchial dysplasia in high-risk smokers and patients with lung cancer. However, EGFR inhibitors were not effective in unselected patients with advanced NSCLC. After the identification of sensitizing EGFR mutations, tyrosine kinase inhibitors became the cornerstone of treatment for patients with EGFR-mutated NSCLC. However, other drugs were developed to target EGFR in the EGFR-wild type population, such as monoclonal antibodies. Cetuximab is an anti-EGFR monoclonal antibody, and has been a focus over the past two decades. Though not approved in NSCLC due to marginal and inconsistent effects in phase 3 trials, research aimed to discover biomarkers to identify a subgroup of the population that might benefit. This includes a composite score that evaluates histology, immunohistochemistry, and gene copy amplification. This article reviews the history of the development and discontinuation of monoclonal antibodies in NSCLC and discusses the role of biomarkers in the treatment of advanced EGFR-wild type NSCLC.

Dual-Function Antibody Conjugate-Enabled Photoimmunotherapy Complements Fluorescence and Photoacoustic Imaging of Head and Neck Cancer Spheroids.

Several molecular-targeted imaging and therapeutic agents are in clinical trials for image-guided surgery and photoimmunotherapy (PIT) for head and neck cancers. In this context, we have previously reported the development, characterization, and specificity of a dual-function antibody conjugate (DFAC) for multimodal imaging and photoimmunotherapy (PIT) of EGFR-overexpressing cancer cells. The DFAC reported previously and used in the present study comprises an EGFR-targeted antibody, cetuximab, conjugated to benzoporphyrin derivative (BPD) for fluorescence imaging and PIT and a Si-centered naphthalocyanine dye for photoacoustic imaging. We report here the evaluation and performance of DFAC in detecting microscopic cancer spheroids by fluorescence and photoacoustic imaging along with their treatment by PIT. We demonstrate that while fluorescence imaging can detect spheroids with volumes greater than 0.049 mm3, photoacoustic imaging-based detection was possible even for the smallest spheroids (0.01 mm3) developed in the study. When subjected to PIT, the spheroids showed a dose-dependent response, with smaller spheroids (0.01 and 0.018 mm3) showing a complete response with no recurrence when treated with 100 J/cm2. Together our results demonstrate the complementary imaging and treatment capacity of DFAC. This potentially enables fluorescence imaging to assess the presence of tumor on a macroscopic scale, followed by photoacoustic imaging for delineating tumor margins guiding surgical resection and elimination of any residual microscopic disease by PIT, in a single intraoperative setting.

Unraveling the signaling mechanism behind astrocytoma and possible therapeutics strategies: A comprehensive review.

A form of cancer called astrocytoma can develop in the brain or spinal cord and sometimes causes death. A detailed overview of the precise signaling cascade underlying astrocytoma formation has not yet been revealed, although various factors have been investigated. Therefore, our objective was to unravel and summarize our current understanding of molecular genetics and associated signaling pathways with some possible therapeutic strategies for astrocytoma. In general, four different forms of astrocytoma have been identified in individuals, including circumscribed, diffuse, anaplastic, and multiforme glioblastoma, according to a recent literature review. All types of astrocytoma have a direct connection with some oncogenic signaling cascade. Common signaling is MAPK cascade, including Ras-Raf-ERK, up-regulated with activating EGFR/AKT/PTEN/mTOR and PDGFR. Recent breakthrough studies found that BRAF mutations, including KIAA1549: BRAF and BRAF V600E are responsible for astrocytoma progression. Additionally, cancer progression is influenced by mutations in some tumor suppressor genes, such as the Tp53/ATRX and MGMT mutant. As synthetic medications must cross the blood-brain barrier (BBB), modulating signal systems such as miRNA is the primary option for treating patients with astrocytoma. However, available surgery, radiation therapy, and experimental therapies such as adjuvant therapy, anti-angiogenic therapy, and EGFR-targeting antibody drug are the usual treatment for most types of astrocytoma. Similar to conventional anticancer medications, some phytochemicals slow tumor growth by simultaneously controlling several cellular proteins, including those involved in cell cycle regulation, apoptosis, metastatic spread, tyrosine kinase, growth factor receptor, and antioxidant-related proteins. In conclusion, cellular and molecular signaling is directly associated with the development of astrocytoma, and a combination of conventional and alternative therapies can improve the malignancy of cancer patients.

IGF2BP3 promotes the progression of colorectal cancer and mediates cetuximab resistance by stabilizing EGFR mRNA in an m6A-dependent manner

Insulin-like growth factor 2 mRNA-binding protein 3 (IGF2BP3), an RNA-binding protein, is associated with tumorigenesis and progression. However, the exact molecular mechanisms of IGF2BP3 in colorectal cancer (CRC) oncogenesis, progression, and drug resistance remain unclear. This study found that IGF2BP3 was upregulated in CRC tissues. Clinically, the elevated IGF2BP3 level is predictive of a poor prognosis. Functionally, IGF2BP3 enhances CRC tumorigenesis and progression both in vitro and in vivo. Mechanistically, IGF2BP3 promotes epidermal growth factor receptor (EGFR) mRNA stability and translation and further activates the EGFR pathway by serving as a reader in an N6-methyladenosine (m6A)-dependent manner by cooperating with METTL14. Furthermore, IGF2BP3 increases the drug resistance of CRC cells to the EGFR-targeted antibody cetuximab. Taken together, our results demonstrated that IGF2BP3 was a functional and clinical oncogene of CRC. Targeting IGF2BP3 and m6A modification may therefore offer rational therapeutic targets for patients with CRC.

Predictive biomarkers for treatment with amivantamab plus lazertinib among EGFR-mutated NSCLC in the post-osimertinib setting: Analysis of tissue IHC and ctDNA NGS.

9013 Background: Amivantamab (ami) is a bispecific antibody targeting EGFR and MET with immune cell-directing activity, and lazertinib (laz) is a brain-penetrant, third-generation EGFR tyrosine kinase inhibitor. In a previous report, the overall response rate (ORR) of ami+laz in the post-osimertinib (osi) setting was 36%, with median duration of response of 9.6 months (Bauml JCO 2021; 39:15_suppl, 9006). Exploratory analyses suggested certain immunohistochemistry (IHC) and ctDNA-based next-generation sequencing (NGS) biomarkers may enrich for response. A prospective study was conducted to further evaluate these potential biomarkers. Methods: CHRYSALIS-2 (NCT04077463), an ongoing phase 1/1b study, examines the efficacy (ORR per RECIST v1.1) of ami+laz in patients (pts) with EGFR-mutated NSCLC. Cohort D enrolled osi-relapsed, chemotherapy-naïve pts with EGFR exon 19 deletion or L858R mutated advanced NSCLC who had tumor tissue for IHC staining and plasma for ctDNA NGS collected after their most recent therapy. Training and validation subsets identified biomarker criteria and predictive validity, respectively. A Bayesian posterior probability (biomarker positive group ORR is ≥35% and negative group ORR is ≤20%) was predefined to be ≥85% for acceptance. Results: There were 101 response-evaluable pts enrolled in Cohort D. A total of 87 pts had detectable baseline ctDNA and 77 pts had evaluable MET IHC. The training set (n = 50) identified IHC-based MET expression of 3+ staining on ≥25% of tumor cells (MET+) as a potential predictive biomarker, and the validation set (n = 27) confirmed these results. Of those with MET IHC data, 28/77 (36%) were MET+. The overall ORR for MET+ was 61% (95% CI, 41–78) and 12% (95% CI, 5–25) for MET-, with median PFS for MET+ not reached (95% CI, 4.3–NE) vs 4.1 months (95% CI, 2.8–5.7) for MET-. NGS evaluation of ctDNA did not identify predictive biomarkers meeting predetermined criteria. Of note, only 1 pt was identified by ctDNA as having MET amplification (the pt was also MET+ by IHC). Further details will be provided at the time of presentation. Conclusions: MET+ by IHC may be a predictive biomarker for response to ami+laz in the post-osi, chemotherapy-naïve setting. In contrast, molecular profiling with ctDNA failed to identify a subgroup of pts more likely to benefit. Ami+laz represents a potential chemotherapy-free option for pts with EGFR-mutated advanced NSCLC who have progressed on osi and are also MET+ by IHC. Clinical trial information: NCT04077463 .

Abstract CT012: Clinical activity of MCLA-158 (petosemtamab), an IgG1 bispecific antibody targeting EGFR and LGR5, in advanced head and neck squamous cell cancer (HNSCC)

Abstract EGFR is a known driver of cancer growth, and leucine-rich, repeat-containing, G-protein coupled receptor 5 (LGR5) is a transmembrane receptor expressed on cancer stem cells. Petosemtamab is a human, common light chain, IgG1 bispecific antibody with ADCC-enhanced activity, targeting EGFR and LGR5, which has shown potent antitumor activity in patient (pt)-derived HNSCC xenograft models. In the dose escalation part of an ongoing phase 1/2 study, the RP2D was established at 1500 mg Q2W, 4 week cycle (JCO 2021:39.3 Sup 62). Petosemtamab is being investigated in the expansion part in pts with selected advanced solid tumors. Promising activity was seen in HNSCC pts previously treated with both platinum-based chemotherapy and checkpoint inhibitors (MCT 2021:20 Sup12 P185). We present data of the expanded HNSCC cohort treated at the RP2D. Primary objective (expansion): investigator-assessed ORR per RECIST 1.1. Secondary objectives: ORR, DOR, PFS (per investigator and central review), OS and safety/tolerability. Key eligibility criteria: advanced/metastatic HNSCC, prior standard therapy, ECOG PS 0-1, measurable disease (RECIST 1.1), baseline tumor biopsy. At the data cutoff date (28 Nov 2022), 49 HNSCC pts were treated. Median age was 63 years (range 31-77), ECOG PS 0/1: 13/35 pts, and 78% were male. Most frequent primary tumor locations were oropharynx (35%), oral cavity (31%), and larynx (16%). Pts received a median of 2 (range 1-4) lines of prior systemic therapy, including anti-PD-1/PD-L1 in 96% of pts and platinum-based chemotherapy in 92% of pts; 2 pts received prior cetuximab. A median of 4 treatment cycles (range 1-21) was administered, with 17 pts continuing on therapy at the cutoff. Among 42 pts evaluable for efficacy (≥2 cycles and ≥1 postbaseline scan, or early PD), ORR per investigator was 35.7% (15/42), including 1 CR (ongoing after 18 months), 12 PRs, and 2 unconfirmed PRs with treatment ongoing at the cutoff. 15 pts had SD and DCR was 71.4%. Median DOR was 6.0 months (95%CI=3.3-not calculable). Median PFS was 5.0 months (95%CI=3.2-6.8). Of 78 pts treated at the RP2D (escalation and all expansion cohorts), the most frequent AEs regardless of causality (all grades/G3-4) were rash (33%/0%), hypotension (26%/6%), dyspnea (26%/4%), nausea (26%/1%), dermatitis acneiform (24%/1%), blood magnesium decreased (19%/5%), erythema (19%/0%), diarrhea (19%/0%); IRRs (composite term) were reported in 74%/21% of pts, mostly at the first infusion, and all resolved. 5 pts (6%) discontinued treatment due to IRRs on Day 1. 1 esophageal cancer pt died due to unrelated G5 GI bleeding. Retrospective biomarker analyses will be presented. Petosemtamab demonstrates promising clinical efficacy with a manageable safety profile in pretreated HNSCC pts. Further clinical development in HNSCC is planned with petosemtamab monotherapy and in combination with SOC. Citation Format: Ezra E. Cohen, Jérôme Fayette, Amaury Daste, Caroline Even, Christophe Le Tourneau, Irene Brana, Esma Saada, Elisa Fontana, Lara Iglesias, Shumei Kato, Rocio Garcia-Carbonero, Josep Tabernero, Guillem Argilés, Marina Magin, Yu-Ming Shen, Renée de Leeuw, Mohamed Bekradda, Eduardo Pennella, Ernesto Wasserman, Viktoriya Stalbovskaya, Jeroen Lammerts van Bueren, Lokesh Jain, Andrew Joe, Antoine Hollebecque. Clinical activity of MCLA-158 (petosemtamab), an IgG1 bispecific antibody targeting EGFR and LGR5, in advanced head and neck squamous cell cancer (HNSCC) [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 2 (Clinical Trials and Late-Breaking Research); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(8_Suppl):Abstract nr CT012.

Abstract 6677: Preliminary immune correlatives from BCA101 trial show favorable modulation of tumor immune microenvironment

Abstract Background: BCA101 is a bispecific antibody targeting EGFR and TGF-β. TGF-β pathway activation is a hallmark of human immune-excluded tumors, and TGF-β expression is associated with resistance to anti-PD-1 blockade. Neutralization of TGF-β removes an immunosuppressive signal that drives accumulation and polarization of myeloid-derived suppressor cells (MDSCs) and tumor-associated macrophages (TAMs) in solid tumors, while EGFR inhibition targets tumor cell-intrinsic oncogenic signaling. Co-targeting of EGFR and TGF-β directly impacts tumor progression while enhancing the immunogenicity of tumors. Methods: Patients with multiple solid tumor types (CRC, pancreatic, HNSCC, SqNSCLC, and others) were treated with escalating doses of either single agent BCA101 or in combination with anti-PD-1 (pembrolizumab) enrolled on NCT04429542 trial. We performed a variety of immune correlatives on pre- and on-treatment tumor biopsies, including Nanostring-based transcriptomic profiling and IHC for immunophenotypic markers, as well as multiparametric flow cytometric profiling of circulating PBMCs. Results: Our preliminary evidence suggests that neutralization of TGF-β positively alters the systemic immune state (PBMCs) and tumor immune phenotype (mRNA, IHC). Circulating HLA-DR+ monocytes were significantly increased in on-treatment PBMC samples relative to screening. Pathway analysis of on-treatment tumor biopsies revealed enhanced costimulatory signaling, cytokine and chemokine signaling, immune infiltration, and interferon signaling. Top differentially regulated genes in on-treatment biopsies included CCL21, CXCL9, CXCL11, and CXCL13, which recruit T and NK cells. HDAC11, which negative regulates type-I interferon signaling, was significantly reduced in on-treatment biopsies. Notably, two patients with EGFR-amplified squamous non-small cell lung cancer, who both progressed on first-line immunotherapy treatment, were treated with BCA101 at 1250 mg and 1500 mg qw and achieved a partial response (ongoing for 10 months at the time of the data cutoff) and a prolonged stable disease for 11 months, respectively. They exhibited increased CD8+ T cell infiltration and a reduction in TAMs following treatment. Conclusions: Increased abundance of circulating HLA-DR+ monocytes following treatment indicated polarization towards a more positive, Th1-like systemic immune state. We observed enhanced immunogenicity of tumors as assessed by a targeted IO transcriptomic analysis. The results of the pathway analysis were supported by IHC on post-treatment biopsies from a subsequent cohort showing enhanced CD8+ T cell infiltration and stable, or reduced expression of TAM marker CD163. These results indicate that neutralization of TGF-β induces a more permissive tumor immune microenvironment. Citation Format: Patrick H. Lizotte, Paul Paik, Liviu Niculescu, Seng-Lai H. Tan, David Bohr, Elham Gharakhani, Ralf Reiners, Rachel Salazar, Avanish Varshney, Shiv Ram Krishn, Pradip Nair, Cloud Paweletz. Preliminary immune correlatives from BCA101 trial show favorable modulation of tumor immune microenvironment. [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 6677.

Abstract 5675: Discovery and development of an asymmetric IgG-like bispecific antibody targeting EGFR and c-MET, engineered through H-H and H-L chain charge-based heterodimerization

Abstract Background: Lung cancer remains the leading cause of cancer mortality and is the most commonly diagnosed cancer with an estimated 2.2 million cases per year. EGFR, a tyrosine kinase receptor, plays a central role in cellular proliferation, survival, differentiation, and migration. Gain-of-function somatic mutations of EGFR significantly drives disease progression. Small molecule tyrosine kinase inhibitors (TKIs), designed to inhibit EGFR signaling specific to these mutations (e.g., L858R and E19del etc.), have achieved excellent clinical outcomes. However, patients carrying TKI-insensitive mutations (e.g., E20ins) and/or those with disease progression after TKI treatment, by the upregulation of complementary signaling pathways (HGF/c-MET, etc.), remain an unmet medical need. Here, we report the discovery of a fully-human afucosylated anti-EGFR x cMET IgG-like bispecific antibody (PM1080). Methods: PM1080 was generated by introducing unique mutations to the CH1-CL domains of each binding arm to promote correct HC-LC pairing. KIH mutations were also introduced to each CH3 domain to support HC-HC heterodimerization and generate an IgG-like bispecific with one arm binding to EGFR and the other to cMET. PM1080 was expressed via a four-chain expression system in CHO cells carrying a fut8−/− knockout to generate afucosylated molecules with enhanced ADCC activity. Results: Through monovalent affinity measurements, PM1080 interacted with EGFR at single digit nanomolar affinity and at sub-nanomolar affinity to c-MET. PM1080 preferentially bound to EGFR/c-MET double-positive cells rather than EGFR single-positive cells. PM1080 blocked both EGF/EGFR and HGF/c-MET signals via physical blockade of the interaction between EGF/HGF to their corresponding receptors and induced EGFR/c-MET internalization and degradation from the cell surface. Through intricate engineering, PM1080 was expressed via a four-chain system and produced as an afucosylated antibody with significantly improved ADCC function. PM1080 induced potent anti-tumor efficacy against EGFR/c-MET-positive tumor cells as a single agent. Importantly, PM1080 induced anti-tumor activity regardless of EGFR mutations at the intracellular signaling domain, and thus may serve as a promising combinational agent to TKI therapies. As expected, synergistic anti-tumor activity was observed when PM1080 was combined with either 1st or 3rd generation TKIs in both in vitro and in vivo models. Conclusion: PM1080, a bispecific antibody targeting EGFR & c-MET was discovered for cancer treatment. PM1080 displayed potent anti-tumor efficacy either as a single agent or in combination with EGFR TKIs. Preclinical PK and toxicity studies have been conducted to support future first-in-human studies. Citation Format: Ping Wang, Weifeng Huang, Zhenting Zhao, Xiaoniu Miao, Shaogang Peng, Chao Wang, Yao Yan, Tiantian Dong, Andy Tsun, Yingda Xu, Xiaolin Liu, Luo Yi. Discovery and development of an asymmetric IgG-like bispecific antibody targeting EGFR and c-MET, engineered through H-H and H-L chain charge-based heterodimerization. [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 5675.

Abstract 2659: Anti-HER3 antibody, HMBD-001, in combination with an EGFR inhibitor effectively inhibits tumor growth in biomarker-selected pre-clinical models of squamous cell carcinomas

Abstract Squamous cell carcinomas (SCC) originate from stratified squamous epithelium in diverse anatomical locations that share common histological features and genetic mutations. Non-melanoma skin cancer, head and neck cancer (HNSCC), esophageal cancer (ESCC), and non-small cell lung cancer (sqNSCLC) make up the majority of SCC cases and together represent the largest subtype of cancer. There is a significant unmet need for effective treatment options post-progression of standard-of-care therapies. Alterations in receptor tyrosine kinase signaling pathways are commonly found in SCCs, e.g. EGFR is expressed in 90% of HNSCC, 76% of ESCC and 82% of sqNSCLC. However, the combination of EGFR targeting antibody cetuximab with chemotherapy confers limited clinical benefit and even initially sensitive tumors often develop resistance. Studies in SCC have implicated HER3, a key dimerization partner of HER family members, as one likely cause of treatment failure, through HER3 heterodimer activation of PI3K/AKT and MAPK/ERK pathways. In this study, we investigated the potential of combining HER3 and EGFR inhibitors to improve efficacy and overcome resistance. Previous attempts to target HER3 have shown limited clinical efficacy due to suboptimal HER3 inhibition, especially the lack of efficacy in ligand-independent activation mechanisms. They also lacked biomarker stratification for patients where HER3 inhibition would confer benefit. HMBD-001 is a clinical-stage anti-HER3 antibody which is being evaluated in a first-in-human, open-label, multi-center, dose escalation and expansion Phase I/IIa trial in patients with HER3 expressing advanced solid tumors (NCT05057013). HMBD-001 was rationally developed to uniquely block the HER3 heterodimerization interface to potently inhibit all HER3 dimer formation, including ligand-dependent and independent HER3 dimerization. Here, we show that dual blockade of EGFR and HER3 using cetuximab and HMBD-001 robustly inhibits tumor growth and is superior to either monotherapy. In multiple cell and patient derived SCC xenograft models, including models of HNSCC, ESCC and sqNSCLC, selected based on a novel gene signature that is robustly predictive of response, HMBD-001 in combination with cetuximab demonstrated up to 100% tumor growth inhibition and the abrogation of PI3K signalling. This combination was well tolerated with no relapse observed, even after a prolonged period of over 100 days in selected models. This study lays the foundation for testing HMBD-001 in combination with EGFR inhibitors in clinical settings. Better combination strategies of SoC and targeted therapeutics alongside a potent anti-HER3 mAb, in biomarker-selected patient populations, have the potential to meaningfully improve patient outcomes and prolong clinical benefit. Citation Format: Weiyi Toy, Dipti Thakkar, Khang Luu, Bui Ngoc Linh Chi, Jason Lai, Debleena Ray, Namita Gandhi, Alejandro Mas, Konrad Paszkiewicz, Piers Ingram, Jerome Boyd-Kirkup. Anti-HER3 antibody, HMBD-001, in combination with an EGFR inhibitor effectively inhibits tumor growth in biomarker-selected pre-clinical models of squamous cell carcinomas [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 2659.

324 (PB104) - Quantitative analysis of EGFR expression and distribution upon drug treatment in colorectal organoid models

Background: Human organoids are patient-derived tissues that can be expanded in vitro by stimulating the (cancer) stem cells with WNT pathway activators, treatment with differentiation inhibitors and by providing growth factors in an extracellular matrix environment. These organoids form three-dimensional (3D) multicellular structures that polarize and self-organize and express relevant disease-related markers, which makes an organoid biobank ideal for testing the efficacy and mode of action of compounds and antibodies across a diverse patient population. Here, our colorectal organoid biobank and high content imaging platform were used to characterize EGFR dynamics upon drug treatment. Methods: An established biobank of normal colon and colorectal cancer organoid models was characterized for its sensitivity to the growth factor EGF, EGFR-inhibitors (Cetuximab), and standard-of-care compounds. To study the distribution of the EGF receptor, antibodies followed by immunofluorescence staining were used to detect the localization and distribution upon growth factor stimulation. (Inducible) knockdown organoid models with shRNA constructs targeting EGFR were generated to validate the findings. Results: The 3D organoid screening and our proprietary image analysis platform allows the in-depth detection and distinction of growth factor responses that not necessarily only relate to proliferation. By making use of this system, the sensitivity of organoid models to EGF stimulation that are independent of EGF for their outgrowth could be determined. By combining the detection of the target, EGFR, with the detection of targeting EGFR-inhibitory antibodies by immunofluorescence followed by image analysis, the redistribution of the receptor upon EGF-stimulation and in response to antibody exposure could be visualized and quantified. This revealed that EGFR is internalized in the first hours upon EGF stimulation. Along with making use of (inducible) knockdown organoids, it also revealed that different EGFR-targeting antibodies have different effects on the redistribution, internalization, and degradation of EGFR. Conclusions: The high content imaging platform in combination with high throughput screening in 3D-cultured organoid models allows compound and antibody testing in physiologically relevant patient-derived models to not only study the sensitivity to novel compounds, but also for patient stratification and to study the mode of action or understand the underlying relevant biology. The outcome of this work demonstrated that organoids are versatile, multicellular structures that are highly suitable for studying the expression and redistribution of disease-relevant targets. No conflict of interest.

A Probody T Cell-Engaging Bispecific Antibody Targeting EGFR and CD3 Inhibits Colon Cancer Growth with Limited Toxicity.

A conditionally active EGFR-CD3 T cell-engaging Probody therapeutic expands the safety window of bispecific antibodies while maintaining efficacy in preclinical solid tumor settings.