Irreversible Epidermal Growth Factor Receptor Research Articles

Evaluation of drug resistance for EGFR-TKIs in lung cancer via multicellular lung-on-a-chip

Drug resistance to irreversible epidermal growth factor receptor tyrosine kinase inhibitors (EGFR-TKIs) is a primary factor affecting their therapeutic efficacy in human non-small cell lung cancer (NSCLC). NSCLC cells can undergo epithelial-mesenchymal transition (EMT) induced by many factors in the tumour microenvironment (TME), which plays a crucial role in tumour drug resistance. In this study, a multicellular lung-on-a-chip that can realise the cell co-culture of the human non-small cell lung cancer cell line HCC827, human foetal lung fibroblasts (HFL-1), and human umbilical vein endothelial cells (HUVECs) is prepared. The TME was simulated on the chip combined with perfusion and other factors, and the drug evaluation of osimertinib was performed to explore the drug resistance mechanism of EGFR-TKIs. In the early stages, a two-dimensional static cell co-culture was achieved by microchip, and the results showed that HFL-1 cells could be transformed into cancer-associated fibroblasts (CAFs), and HCC827 cells could undergo EMT, both of which were mediated by Interleukin-6 (IL-6). Vimentin (VIM) and Alpha Skeletal Muscle Actin (a-SMA) expression of HFL-1 was upregulated, whereas E-cadherin (E-cad) expression of HCC827 was down-regulated. Further, N-cadherin (N-cad) expression of HCC827 was upregulated. In both the static cell co-culture and multicellular lung-on-a-chip, HCC827 cells with CAFs co-culture or IL-6 treatment developed resistance to osimertinib. Further use of the IL-6 antibody inhibitor tocilizumab could reverse EGFR-TKI resistance to a certain extent. Combination therapy with tocilizumab and EGFR-TKIs may provide a novel therapeutic strategy for overcoming EGFR-TKI resistance caused by EMT in NSCLC. Furthermore, the lung-on-a-chip can simulate complex TME and can be used for evaluating tumour resistance and exploring mechanisms, with the potential to become an important tool for personalised diagnosis, treatment, and biomedical research.

Transcriptomics coupled with proteomics reveals osimertinib-induced myocardial mitochondrial dysfunction

Osimertinib, an irreversible epidermal growth factor receptor tyrosine kinase inhibitor (EGFR-TKI) used for cancer treatment, can cause significant cardiac toxicity. However, the specific mechanism of osimertinib-induced cardiotoxicity is not fully understood. In this study, we administered osimertinib to mice and neonatal rat ventricular myocytes (NRVMs). We observed significant structural and functional damage to the hearts of these mice, along with a marked increase in cardiac injury biomarkers and accompanying ultrastructural damage to mitochondria. We integrated 4D label-free protein quantification and RNA-Seq methods to analyze the sequencing data of NRVMs under osimertinib treatment (0 and 2.5 μM). Kyoto Encyclopedia of Genes and Genomes (KEGG) analysis evidenced that differentially expressed genes (DEGs)and differentially expressed proteins (DEPs) were distinctly enriched for oxidative phosphorylation (OXPHOs). Simultaneously, osimertinib primarily affected the contents of adenosine triphosphate (ATP). Further investigations revealed that osimertinib disrupts the functions of the ATP synthase (complex V), leading to a reduction in ATP production. Taken together, our data demonstrated that osimertinib causes mitochondrial dysfunction, which in turn leads to the onset of cardiac toxicity.

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

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

Effects of H2-Receptor Antagonists on the Exposure of Dacomitinib.

Dacomitinib is an irreversible epidermal growth factor receptor (EGFR) tyrosine kinase inhibitor indicated for the treatment of patients with advanced non-small-cell lung cancer (NSCLC) and EGFR-activating mutations. Proton-pump inhibitors decreased dacomitinib exposure. This analysis summarizes the effect of Histamine-2 receptor antagonists (H2RAs) on dacomitinib exposure. A within-patient comparison of the steady-state trough concentrations (Ctrough,ss) of dacomitinib and its active metabolite and active moiety with and without concomitant use of H2RAs was conducted using a linear mixed effects model with pooled data from 11 clinical studies in patients with NSCLC. An oral absorption physiologically based pharmacokinetic (PBPK) model was constructed and verified using clinical pharmacokinetic (PK) data after a single dose of dacomitinib in healthy volunteers to estimate the effect of gastric pH altered by an H2RA on dacomitinib's PKs. The adjusted geometric mean of the dacomitinib Ctrough,ss of the dacomitinib parent, metabolite and active moiety following co-administration with an H2RA was approximately 86%, 104% and 100% relative to that following dacomitinib 45 mg administration without an H2RA (p > 0.05). The PBPK modeling showed negligible change in dacomitinib maximum concentration (Cmax) and area under the drug concentration-time curve (AUC) over 0-24 h after H2RA administration when compared with those administered dacomitinib alone. Co-administration of an H2RA with dacomitinib is not expected to have any clinically relevant effect on dacomitinib exposure.

EGFR Tyrosine Kinase Inhibitor Lazertinib Activates a Subset of Mouse Sensory Neurons Via TRPA1

Lazertinib (JNJ-73841937, YH25448) is a mutant-selective irreversible epidermal growth factor receptor tyrosine kinase inhibitor targeting both the T790M and activating mutation while sparing wild-type epidermal growth factor receptor. Paresthesia is one of the most common adverse events seen with lazertinib treatment, suggesting that lazertinib could affect the sensory nervous system. However, the mechanism of action for this paresthesia remains unclear. In this study, we investigated whether and how lazertinib affects peripheral sensory neurons. Through Fura-2-based calcium imaging and whole-cell patch clamp recording in primary-cultured dorsal root ganglion (DRG) neurons from adult mice, we found that application of lazertinib elicits spontaneous calcium responses in a subset of small-to-medium-sized neurons. Moreover, lazertinib induced spontaneous firings and hyperexcitability in a subset of transient receptor potential vanilloid 1-lineage DRG neurons and sensitized transient receptor potential ankyrin 1 (TRPA1) response, while sparing transient receptor potential vanilloid 1 response. Lazertinib-responsive neurons were also responsive to capsaicin, further supporting that lazertinib selectively activates nociceptive neurons. Lazertinib-induced calcium responses were pharmacologically blocked with HC-030031 (TRPA1 antagonist) and MDL-12330A (adenylyl cyclase inhibitor), suggesting that lazertinib activates sensory neurons through indirect activation of TRPA1. However, unlike vincristine which produces peripheral neuropathy by axonal degeneration, lazertinib did not cause neurite fragmentation in cultured DRG neurons. Finally, intraplantar injection of lazertinib induced TRPA1-dependent pain-like behaviors in vivo. Collectively, our data suggest a direct effect of lazertinib on nociceptive sensory neurons via TRPA1 selective mechanisms, which could be a putative mechanism of lazertinib-induced sensory abnormalities in clinical patients. PerspectiveThis article presents a TRPA1-dependent, lazertinib-induced activation of mouse sensory neurons in vitro and lazertinib-induced pain-like behaviors in vivo. The same mechanisms may underlie the clinical condition, suggesting that TRPA1 could be a potential therapeutic target to manage lazertinib-induced paresthesia.

Multi-omic profiling and real time ex vivo modelling of imatinib-resistant dermatofibrosarcoma protuberans with fibrosarcomatous transformation.

Dermatofibrosarcoma protuberans (DFSP) is a rare and indolent cutaneous sarcoma, with the risk of aggressive fibro-sarcomatous transformation. Limited effective options are available for un-resectable or metastatic DFSP beyond targeting the oncogenic PDGF pathway with imatinib therapy. We established a patient-derived xenograft (PDX) and cell line model (designated MDFSP-S1) of imatinib-resistant DFSP with fibro-sarcomatous transformation. Whole genome sequencing identified high-level amplification at chromosomes 17 and 22, whilst homozygous deep deletion was demonstrated at chromosome 9 (CDKN2A, CDKN2B, MTAP). RNA sequencing followed by Sanger sequencing confirmed the pathognomonic COL1A1-PDGFB t (17;22) rearrangement in the original tumour, PDX and cell line model. Immunohistochemistry profiles of the PDX model were consistent with the patient's tumour sample (CD34 + /MIB1 + /SOX10- ). Gene set enrichment analysis highlighted top-scoring Hallmark gene sets in several oncogenic signalling pathways, including potentially targetable MTORC1 signalling and angiogenesis pathways. Antiangiogenic agents (sunitinib, regorafenib, pazopanib, axitinib) and the third-generation irreversible epidermal growth factor receptor (EGFR) tyrosine kinase inhibitor osimertinib exhibited modest anti-proliferative activity in the cell line, with IC50 values between 1 and 10µM at 72h. No significant activity was observed with imatinib, palbociclib, everolimus, olaparib, gefitinib and erlotinib (IC50 all > 10µM). In conclusion, we established MDFSP-S1, a new PDX and cell line model of imatinib-resistant DFSP with fibro-sarcomatous transformation.

Role of pelitinib in the regulation of migration and invasion of hepatocellular carcinoma cells via inhibition of Twist1

BackgroundOverexpression of Twist1, one of the epithelial-mesenchymal transition-transcription factors (EMT-TFs), is associated with hepatocellular carcinoma (HCC) metastasis. Pelitinib is known to be an irreversible epidermal growth factor receptor tyrosine kinase inhibitor that is used in clinical trials for colorectal and lung cancers, but the role of pelitinib in cancer metastasis has not been studied. This study aimed to investigate the anti-migration and anti-invasion activities of pelitinib in HCC cell lines.MethodsUsing three HCC cell lines (Huh7, Hep3B, and SNU449 cells), the effects of pelitinib on cell cytotoxicity, invasion, and migration were determined by cell viability, wound healing, transwell invasion, and spheroid invasion assays. The activities of MMP-2 and -9 were examined through gelatin zymography. Through immunoblotting analyses, the expression levels of EMT-TFs (Snail1, Twist1, and ZEB1) and EMT-related signaling pathways such as mitogen-activated protein kinases (MAPKs) and Akt signaling pathways were measured. The activity and expression levels of target genes were analyzed by reporter assay, RT-PCR, quantitative RT-PCR, and immunoblotting analysis. Statistical analysis was performed using one-way ANOVA with Dunnett's Multiple comparison tests in Prism 3.0 to assess differences between experimental conditions.ResultsIn this study, pelitinib treatment significantly inhibited wound closure in various HCC cell lines, including Huh7, Hep3B, and SNU449. Additionally, pelitinib was found to inhibit multicellular cancer spheroid invasion and metalloprotease activities in Huh7 cells. Further investigation revealed that pelitinib treatment inhibited the migration and invasion of Huh7 cells by inducing Twist1 degradation through the inhibition of MAPK and Akt signaling pathways. We also confirmed that the inhibition of cell motility by Twist1 siRNA was similar to that observed in pelitinib-treated group. Furthermore, pelitinib treatment regulated the expression of target genes associated with EMT, as demonstrated by the upregulation of E-cadherin and downregulation of N-cadherin.ConclusionBased on our novel finding of pelitinib from the perspective of EMT, pelitinib has the ability to inhibit EMT activity of HCC cells via inhibition of Twist1, and this may be the potential mechanism of pelitinib on the suppression of migration and invasion of HCC cells. Therefore, pelitinib could be developed as a potential anti-cancer drug for HCC.

Abstract 3499: Inhibition of SOS1 by MRTX0902 augments the anti-tumor response of the targeted EGFR inhibitor osimertinib in NSCLC

Abstract Osimertinib is a third generation, irreversible epidermal growth factor receptor (EGFR) tyrosine kinase inhibitor recommended as a first line therapy in patients with advanced non-small lung cancer (NSCLC) characterized by EGFR activating mutations (exon 19 deletions and exon 21 L858R) and the resistance associated exon 20 T790M mutation, which is present in approximately 40-55% of patients following treatment with first generation EGFR-targeting inhibitors. Unfortunately, osimertinib monotherapy inevitably leads to both EGFR-dependent and EGFR-independent resistance mechanisms that reactivate RTK/MAPK pathway signaling. Thus, exploration of new combination strategies that target RTK/MAPK-mediated bypass of EGFR dependence may circumvent or delay therapeutic resistance are a key research focus. Preclinically, it has been shown that EGFR-mutant NSCLC cell lines are sensitive to inhibition of an upstream node of the MAPK pathway, the Son of Sevenless homolog 1 (SOS1) protein, which functions as a guanine nucleotide exchange factor (GEF) for the RAS subfamily of small GTPases. MRTX0902 is a selective and potent SOS1 inhibitor currently in Phase 1 clinical trials and functions by disrupting the KRAS/SOS1 protein-protein interaction to prevent SOS1-mediated nucleotide exchange on KRAS, ultimately leading to downregulation of KRAS-MAPK pathway signaling. Here we demonstrate that dual inhibition of SOS1 and mutant EGFR by osimertinib results in greater anchorage-independent (3D) cell death and further downregulation of MAPK and PI3K/AKT pathway signaling compared to single agent osimertinib treatment. In our current study, we characterized the anti-tumor effects of SOS1 inhibition by MRTX0902 as a monotherapy and in combination with osimertinib in EGFR mutant models of NSCLC. While single agent MRTX0902 treatment effectively inhibited EGFR mutant cell survival, combination treatment of MRTX0902 with osimertinib resulted in (1) deeper and sustained inhibition of MAPK and PI3K/AKT pathway signaling, (2) enhanced inhibition of 3D cell viability and increased apoptosis, and (3) increased anti-tumor efficacy compared to osimertinib monotherapy in EGFR mutant CDX models in vivo. These studies uncover the potential clinical application of combined vertical inhibition of RTK/MAPK pathway signaling by osimertinib and MRTX0902 and ultimately aide in the understanding of EGFR and RAS biology in targeted cancer therapy. Citation Format: Shilpi Khare, Niranjan Sudhakar, Jade Laguer, David M. Briere, Larry Yan, Allan Hebbert, Andrew Calinisan, Lars D. Engstrom, Fadia Qiryaqos, Peter Olson, James G. Christensen, Jacob R. Haling. Inhibition of SOS1 by MRTX0902 augments the anti-tumor response of the targeted EGFR inhibitor osimertinib in NSCLC [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 3499.

A real-world pharmacovigilance study of FDA Adverse Event Reporting System (FAERS) events for osimertinib

Osimertinib was a third-generation, irreversible epidermal growth factor receptor tyrosine kinase inhibitor (EGFR-TKI), which approved by the US Food and Drug Administration (FDA) in 2015 for treatment of non-small cell lung cancer (NSCLC). Our study was to explore the adverse events (AEs) caused by osimertinib through data mining of the US FDA Adverse Event Reporting System (FAERS), and provide reference for clinical safety. Data of osimertinib were collected from the FAERS database covering the period from first quarter of 2016 to the fourth quarter of 2021. Disproportionality analyses was employed to quantify the associated AE signals of osimertinib and detect the risk signals from the data in the FAERS database. Reporting odds ratio (ROR) was used to detect the risk signals from the data in the FAERS database. The definition relied on system organ class (SOCs) and preferred terms (PTs) by the Medical Dictionary for Regulatory Activities (MedDRA). Totally, 9,704,33 reports were collected from the FAERS database, 10,804 reports of osimertinib were identified as the ‘primary suspected (PS)’ AEs. Osimertinib induced AEs occurred in 27 organ systems. 68 significant disproportionality PTs satisfying with the four algorithms were retained at the same time. Unexpected significant AEs such as scrotal volvulus, hepatic function abnormal, venous thromboembolisms might also occur. The median onset time of osimertinib-associated AEs was 58 days (interquartile range [IQR] 14–212 days), and the majority of the AEs occurred within the first 30 days after osimertinib initiation. Our study found significant new AEs signals of osimertinib and might provide support for clinical monitoring and risk identification of osimertinib.

Prediction of pyrotinib exposure based on physiologically-based pharmacokinetic model and endogenous biomarker.

Pyrotinib, a novel irreversible epidermal growth factor receptor dual tyrosine kinase inhibitor, is mainly (about 90%) eliminated through cytochrome P450 (CYP) 3A mediated metabolism in vivo. Meanwhile, genotype is a key factor affecting pyrotinib clearance and 4β-hydroxycholesterol is an endogenous biomarker of CYP3A activity that can indirectly reflect the possible pyrotinib exposure. Thus, it is necessary to evaluate the clinical drug-drug interactions (DDI) between CYP3A perpetrators and pyrotinib, understand potential exposure in specific populations including liver impairment and geriatric populations, and explore the possible relationships among pyrotinib exposure, genotypes and endogenous biomarker. Physiologically-based pharmacokinetic (PBPK) model can be used to replace prospective DDI studies and evaluate external and internal factors that may influence system exposure. Herein, a basic PBPK model was firstly developed to evaluate the potential risk of pyrotinib coadministration with strong inhibitor and guide the clinical trial design. Subsequently, the mechanistic PBPK model was established and used to quantitatively estimate the potential DDI risk for other CYP3A modulators, understand the potential exposure of specific populations, including liver impairment and geriatric populations. Meanwhile, the possible relationships among pyrotinib exposure, genotypes and endogenous biomarker were explored. With the help of PBPK model, the DDI clinical trial of pyrotinib coadministration with strong inhibitor has been successfully completed, some DDI clinical trials may be waived based on the predicted results and clinical trials in specific populations can be reasonably designed. Moreover, the mutant genotypes of CYP3A4*18A and CYP3A5*3 were likely to have a limited influence on pyrotinib clearance, and the genotype-independent linear correlation coefficient between endogenous biomarker and system exposure was larger than 0.6. Therefore, based on the reliable predicted results and the linear correlations between pyrotinib exposure and endogenous biomarker, dosage adjustment of pyrotinib can be designed for clinical practice.

EP08.02-040 Dacomitinib Induced Febrile Neutropenia: a Rare Serious Adverse Event

Dacomitinib, a second-generation oral irreversible epidermal growth factor receptor (EGFR) tyrosine kinase inhibitor, has improved overall survival in metastatic non-small lung cancer patients harbouring EGFR mutations. The common adverse reactions associated with dacomitinib are diarrhoea and dermatological toxicities while severe febrile neutropenia has not been reported in literature.

Abstract 1125: Elucidating the transcriptomic response to EGFR-targeted therapy in EGFR-driven glioblastoma

Abstract Glioblastoma (GBM) is the most common malignant brain tumor in adults with a dismal 15-month median survival. Standard therapy consisting of surgical resection, radiation, and temozolomide has been unsuccessful in meaningfully extending survival and preventing recurrence; thus, novel therapeutics are urgently needed. One proposed targeted treatment strategy for GBM involves using small molecule inhibitors against common genetic mutations. Epidermal growth factor receptor (EGFR) is the most commonly overexpressed oncogene in GBM (~56%). While EGFR tyrosine kinase inhibitors (TKI) have shown promise in other cancers, GBM clinical trials with EGFR TKI have failed. One reason for this failure is the development of adaptive therapeutic resistance. Understanding the mechanisms behind drug resistance is essential for the development of novel, effective therapeutics for GBM. To better understand adaptive resistance in GBM, we utilized two genetically engineered mouse astrocyte lines harboring common GBM mutations: Cdkn2a-/-, EGFRvIII (CEv3) and Cdkn2a-/-, Pten-/-, EGFRvIII (CEV3P). CDKN2A and PTEN are commonly deleted or otherwise inactivated tumor suppressor genes in GBM while the vIII variant of EGFR is the single most common oncogene mutation, making it an attractive therapeutic target. Cell lines CEv3 and CEv3P are both sensitive to neratinib, an irreversible second-generation EGFR TKI, at IC50 of 0.24μM and 0.13µM, respectively. To better understand adaptive response to neratinib treatment, we profiled the transcriptome with RNA sequencing at 0, 4, 24, and 48 hours. Our data shows that kinome rewiring is detectable after just 4 hours of treatment and sustained through 48 hours, with differential expression of 70% or more of the expressed kinome. We propose that differentially expressed kinases in response to neratinib can potentially activate alternative signaling pathways that bypass EGFR inhibition, which ultimately confers resistance to EGFR targeted therapy. Furthermore, we hypothesize that the epigenome is directly responsible for this adaptive kinome response through BRD4 dependent enhancer remodeling. Because dual therapy against EGFR and BRD4 has shown promising results in other cancers, targeting the epigenome through BRD4 represents a potential combination therapy with EGFR TKI in GBM. To profile BRD4-associated epigenomic changes, we used Cleavage Under Targets and Release Using Nuclease (CUT&amp;RUN) to interrogate several regulatory marks (H3K4me1, K3K4me3, H3K27ac) in addition to BRD4. We seek to integrate RNA sequencing and CUT&amp;RUN data to determine if kinases differentially expressed following neratinib treatment correlate with epigenetic marks for their respective enhancer(s). This work will provide insight into the adaptive resistance mechanism of EGFR driven GBM. Citation Format: Benjamin Lin, Julia Ziebro, Kasey R. Skinner, Abigail Shelton, Erin Smithberger, Ryan Bash, Frank B. Furnari, Ryan Miller. Elucidating the transcriptomic response to EGFR-targeted therapy in EGFR-driven glioblastoma [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 1125.

Mefatinib as first-line treatment of patients with advanced non–small cell lung cancer harboring rare EGFR mutations.

9102 Background: Mefatinib is a novel, second-generation, irreversible epidermal growth factor receptor (EGFR)-tyrosine kinase inhibitor (TKI). A Phase Ib/II study has showed promising efficacy in patients with advanced EGFR (19del/L858R) mutant non-small cell lung cancer (NSCLC). This study is aimed to assess the efficacy and safety of mefatinib as first-line therapy for advanced rare EGFR mutations (G719X/S768I/L861Q) NSCLC. Methods: In this phase II study, we enrolled patients with stage IIIB-IV lung adenocarcinoma with at least one mutation in G719X, L861Q, and S768I who hadn¡¯t received front-line anticancer therapy. Other concurrent EGFR mutations were allowed with the exception of Ex19del, L858R, and exon 20 insertions. Eligible patients were treated with mefatinib 80 mg orally once daily. The primary endpoint was objective response rate (ORR) according to RECIST 1.1 criteria. Results: A total of 21 patients (median age 57.6, 47.62% male) have been enrolled, 80.95% with G719X, 33.3% S768I, and 19.05% L861Q. Six (28.57%) patients had concurrent mutations of G719X and S768I, and one (4.76%) patient had co-mutations of G719X and L861Q. As of data cut-off (Jan, 6, 2022), median follow-up was 25.1 months. Among the 21 efficacy evaluable patients, ORR was 85.71% (95% CI, 63.66-96.95) with a duration of response (DOR) of 22.2 months (95% CI, 8.4-NA). Disease control rate (DCR) was 100% (95% CI, 83.89-100.00). Median progression-free survival (mPFS) was 20.6 months (95% CI, 8.3-NA). Median overall survival (OS) was not reached.. The most common treatment-related adverse events (TRAEs) were rash (20, 95.24%), diarrhea (19, 90.48%), stomatitis (15, 71.43%), and pandactilitis (9, 42.86%). Grade 3 TRAEs were reported in 47.63% patients. Common Grade 3 TRAEs (¡Ý5%) included diarrhea (8, 38.10%) and rash (5, 23.81%). No ¡ÝGrade 4 TRAE or treatment-related SAE reported. 33.33% (n=7) of patients experienced dose reduction due to AEs (mainly diarrhea and rash). All TRAEs were reversible and remained stable or recovered without sequelae after dose reduction. None of the patients discontinued treatment or died due to TRAE. Conclusions: Mefatinib has shown promising anti-tumor activity and a favorable safety profile in patients with advanced NSCLC harboring rare EGFR mutations. Clinical trial information: CTR20190110. [Table: see text]

Triple positive lung cancer: A case report

Background: Targeted therapies in nonsmall cell lung cancer has changed the landscape of management and carved the disease in to more different sub types. Despite of considerable initial response to 1st generation and 2nd generation tyrosine kinase inhibitors patients develop resistance in the due course. Secondary mutations are due to threonine and methionine substitution at 790 (T790M) of EGFR. T790M mutation are resistant to 1st and 2nd generation TKI.Osimertinib is a irreversible third generation epidermal growth factor receptor tyrosine kinase inhibitor effective against EGFR T790M mutation positive lung cancer. Patients are inescapable of developing resistance with Osimertinib in spite of initial response and leaving no further definite therapeutic options. In 20-30% patients with osimertinib resistance develop EGFR C797S mutation. Our objective is to show the patient journey with primary, secondary mutation withT790M and tertiary mutation in C797S. Key Messages: Prospective molecular tumor profiling is now the standard of care in the treatment of metastatic NSCLC. Re-biopsy or liquid biopsy on progression of first and second line TKI to look for T790M has already been in routine practice. Re-biopsy or liquid biopsy on progression of third line TKI and molecular profiling can guide us in further management.

Rationale and design of a phase II trial of dacomitinib in advanced non-small cell lung cancer patients with uncommon epidermal growth factor receptor mutations: a prospective and single arm study (DANCE study)

BackgroundDacomitinib is a second-generation, irreversible epidermal growth factor receptor tyrosine kinase inhibitor (EGFR-TKI). ARCHER-1050 showed that this agent can improve progression-free survival and overall survival in advanced non-small cell lung cancer patients with sensitive EGFR mutation compared to gefitinib. However, it is unclear whether dacomitinib is effective in patients with sensitizing uncommon EGFR mutations in exon 18–21. The aim of this study is to investigate the safety and efficacy of dacomitinib in these patients.MethodsThis is a single arm, prospective, open label and phase II trial. Sample size will be calculated by a minimax two-stage design method based on the following parameters: α = 0.075, 1-β = 0.9, P0 = 0.20, P1 = 0.45 and a dropout rate of 10%. A total of 30 eligible patients will be included. Patients will receive continuous oral therapy with dacomitinib (45 mg/day) until disease progression, withdrawal of consent, or unacceptable toxicity, whichever occurs first. The primary endpoint is objective response rate (ORR) per RECIST version 1.1, as assessed by investigators’ review. The second endpoint is disease control rate (DCR), PFS, OS, and safety.DiscussionWe conduct a single arm, phase II study to investigate the safety and efficacy of dacomitinib in advanced NSCLC patients with sensitizing uncommon EGFR mutations. The results of the DANCE study will provide new data regarding efficacy and safety of these patients.Trial registrationNCT04504071

Baicalin Enhanced Oral Bioavailability of Sorafenib in Rats by Inducing Intestine Absorption

Background: Sorafenib (SOR) is an oral, potent, selective, irreversible epidermal growth factor receptor tyrosine kinase inhibitor (EGFR-TKI) used as the first-line therapy for advanced hepatocellular carcinoma (HCC). Baicalin (BG) is used as adjuvant therapy for hepatitis, which accounts for the leading cause of the development of HCC, and is commonly coadministered with SOR in clinic. The purpose of the current study was to characterize the pharmacokinetic changes of SOR and the potential mechanism when SOR is administered concomitantly with BG in rats for single and multiple doses. Methods: Parallel randomized pharmacokinetic studies were performed in rats which received SOR (50 mg/kg, i.g.) alone or coadministered with BG (160 mg/kg, i.g.) for single and multiple doses (7 days). Plasma SOR levels were quantified by ultra-performance liquid chromatography–tandem mass spectrometry (UPLC-MS/MS). Rat liver microsomes (RLMs) which isolated from their livers were analyzed for CYP3A and SOR metabolism activities. The inhibitory effect of BG on the metabolism of SOR was also assessed in pooled human liver microsomes (HLMs). The effects of BG on the intestine absorption behaviors of SOR were assessed in the in situ single-pass rat intestinal perfusion model. Results: Coadministration with BG (160 mg/kg, i.g.) for single or multiple doses significantly increased the Cmax, AUC0–t, and AUC0–∞ of orally administered SOR by 1.68-, 1.73-, 1.70-fold and 2.02-, 1.65-, 1.66- fold in male rats and by 1.85-, 1.68-, 1.68-fold and 1.57-, 1.25-, 1.24- fold in female rats, respectively (p < 0.01 or p < 0.05). In vitro incubation assays demonstrated that there were no significant differences of K m , V max , and CL int of 1-OH MDZ and SOR N-oxide in RLMs between control and multiple doses of BG-treated groups. BG has no obvious inhibitory effects on the metabolism of SOR in HLMs. In comparison with SOR alone, combining with BG significantly increased the permeability coefficient (P eff ) and absorption rate constant (K a ) of the SOR in situ single-pass rat intestinal perfusion model. Conclusion: Notably enhanced oral bioavailability of SOR by combination with BG in rats may mainly account for BG-induced SOR absorption. A greater understanding of potential DDIs between BG and SOR in rats makes major contributions to clinical rational multidrug therapy in HCC patients. Clinical trials in humans and HCC patients need to be further confirmed in the subsequent study.

P51.03 Oritinib (SH-1028), a Third-generation EGFR-TKI in Advanced NSCLC Patients with Positive EGFR T790M: Results of a Single-arm Phase Ib Trial

Oritinib (SH-1028) is an oral, high-selective irreversible epidermal growth factor receptor tyrosine kinase inhibitor (EGFR TKI) selectively targeting both sensitizing EGFR and EGFR T790M mutations. Herein, we report the preliminary efficacy and safety of oritinib in EGFR T790M-positive advanced non-small-cell lung cancer (NSCLC) patients previously treated with EGFR TKIs from dose-extension cohort of phase Ib study (NCT03823807).

Pyrotinib combined with thalidomide in advanced non-small-cell lung cancer patients harboring HER2 exon 20 insertions (PRIDE): protocol of an open-label, single-arm phase II trial

BackgroundStandard therapy for human epidermal growth factor receptor 2 (HER2)-mutant non-small-cell lung cancer (NSCLC) is lacking. The clinical benefits with pan-HER inhibitors (afatinib, neratinib, and dacomitinib), anti-HER2 antibody drug conjugate (ADC) trastuzumab emtansine, and an emerging irreversible tyrosine kinase inhibitor (TKI) poziotinib were modest. Another new ADC trastuzumab deruxtecan showed encouraging outcomes, but only phase I study was completed. Pyrotinib, another emerging irreversible epidermal growth factor receptor (EGFR)/HER2 dual TKI, has been approved in HER2-positive breast cancer in 2018 in China. It has shown promising antitumor activity against HER2-mutant NSCLC in phase II trials, but pyrotinib-related diarrhea remains an issue. The antiangiogenic and immunomodulatory drug thalidomide is a cereblon-based molecular glue that can induce the degradation of the IKAROS family transcription factors IKZF1 and IKZF3. The use of thalidomide can also decrease gastrointestinal toxicity induced by anti-cancer therapy.MethodsThis is an open-label, single-arm phase II trial. A total of 39 advanced NSCLC patients with HER2 exon 20 insertions and ≤ 2 lines of prior chemotherapy will be recruited, including treatment-naïve patients who refuse chemotherapy. Patients are allowed to have prior therapy with immune checkpoint inhibitors and/or antiangiogenic agents. Those who have prior HER2-targeting therapy or other gene alterations with available targeted drugs are excluded. Eligible patients will receive oral pyrotinib 400 mg once daily and oral thalidomide 200 mg once daily until disease progression or intolerable toxicity. The primary endpoint is objective response rate.DiscussionThe addition of thalidomide to pyrotinib is expected to increase the clinical benefit in advanced NSCLC patients with HER2 exon 20 insertions, and reduce the incidence of pyrotinib-related diarrhea. We believe thalidomide is the stone that can hit two birds.Trial registrationClinicalTrials.gov Identifier: NCT04382300. Registered on May 11, 2020.

Abstract 1466: ORIC-114, a brain penetrant, orally bioavailable, irreversible inhibitor selectively targets EGFR and HER2 exon20 insertion mutants and regresses intracranial NSCLC xenograft tumors

Abstract Genomic insertions within exon20 of both epidermal growth factor receptor (EGFR) and human epidermal growth factor receptor 2 (HER2) are oncogenic drivers most commonly found in non-small cell lung cancer (NSCLC) but also occurring in multiple other tumor types. Exon20 insertions render the receptors resistant to currently approved inhibitors, giving patients with tumors harboring such insertions a worse prognosis than with other activating EGFR mutations. Moreover, approximately one-third of patients with exon20 insertion mutations may develop central nervous system (CNS) metastases over the course of their disease. To address this unmet medical need, ORIC-114, a brain penetrant, orally bioavailable, irreversible small molecule inhibitor was designed to target exon20 insertions in EGFR and HER2. ORIC-114 is highly selective to the EGFR family of receptors, showing superior kinome selectivity compared with other reported exon20 inhibitors. In biochemical assays ORIC-114 displays low nanomolar potency, and importantly has enhanced potency on the EGFR exon20 NPG insertion relative to wildtype EGFR protein. ORIC-114 also demonstrates low nanomolar potency across exon20 insertion variants using cell-based assays measuring EGFR phosphorylation, downstream signaling and cell viability. ORIC-114 is readily brain available across multiple preclinical species hence studies were undertaken to investigate activity in both subcutaneous and intracranial tumor models. Herein, we explored the in vivo activity of ORIC-114. Consistent with our in vitro findings, robust activity was observed in EGFR exon20 patient-derived xenograft models using once daily oral administration, with greater than 90% tumor growth inhibition in the absence of body weight loss. Moreover, these significant antitumor effects correlate with decreased pharmacodynamic response as measured by phosphorylated EGFR in terminal tumors. To investigate whether the brain-penetrant attributes of ORIC-114 translate into therapeutic CNS activity, we utilized an intracranial luciferase-labeled EGFR mutant cell line model. Once daily oral administration of ORIC-114 significantly regressed established intracranial NSCLC tumors, demonstrating greater efficacy than TAK-788, commensurate with the superior brain to plasma exposure of ORIC-114. Taken together, these data establish ORIC-114 as a selective, irreversible, and brain penetrant EGFR inhibitor, making it a promising therapeutic candidate for development in patients with tumors harboring EGFR and HER2 exon20 insertions, including those with CNS metastases. ORIC-114 is anticipated to enter a global Phase 1/2 tumor-agnostic trial in genetically defined cancers in the second half of 2021. Citation Format: Melissa R. Junttila, Sunghwan Kim, Younho Lee, Hwan Kim, Juhee Kang, Jiyoon Seok, Jihye Yoo, Youngyi Lee, Dong-Hyuk Seo, Jung Beom Son, Daekwon Kim, Hwan Geun Choi, Nam Doo Kim, Akash Das, Dena Sutimantanapi, Tatiana Zavorotinskaya, Chelsea Chen, Jae Chang, Matthew Panuwat, Lori Friedman. ORIC-114, a brain penetrant, orally bioavailable, irreversible inhibitor selectively targets EGFR and HER2 exon20 insertion mutants and regresses intracranial NSCLC xenograft tumors [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2021; 2021 Apr 10-15 and May 17-21. Philadelphia (PA): AACR; Cancer Res 2021;81(13_Suppl):Abstract nr 1466.

Evaluation of the Effect of Proton Pump Inhibitors on the Efficacy of Dacomitinib and Gefitinib in Patients with Advanced Non-Small Cell Lung Cancer and EGFR-Activating Mutations.

IntroductionDacomitinib and gefitinib are irreversible epidermal growth factor receptor (EGFR) tyrosine kinase inhibitors (TKI) indicated for the first-line treatment of patients with advanced non-small cell lung cancer (NSCLC) and EGFR-activating mutations. Pharmacokinetic (PK) studies in healthy volunteers suggested that acid-reducing drugs such as proton pump inhibitors (PPI) decreased dacomitinib and gefitinib exposure by limiting the pH-dependent absorption. This analysis retrospectively evaluates the effect of concomitant PPI use on dacomitinib exposure and on progression-free survival (PFS) and overall survival (OS) in patients treated with dacomitinib 45 mg QD or gefitinib 250 mg QD in a 1:1 randomized phase 3 study (ARCHER 1050).MethodsThe analysis grouped all patients (n = 452) treated in each arm of the study as non-PPI users, PPI users, or extensive PPI users. PFS and OS data were presented by Kaplan–Meier plots and analyzed using Cox proportional hazards models. Dacomitinib exposure was compared using a linear mixed-effects model.ResultsResults showed that dacomitinib PFS and OS did not differ significantly when comparing PPI users (N = 59) to non-PPI users (N = 152), while extensive PPI users (N = 24) had shorter PFS [hazard ratio (HR): 1.94, p = 0.011] and OS (HR: 1.77, p = 0.027) when compared to non-PPI users. For patients treated with gefitinib, PFS did not differ significantly when comparing PPI users (N = 51) and extensive PPI users (N = 19) to non-PPI users (N = 159); however, both PPI users (HR: 1.65, p = 0.007) and extensive PPI users (HR: 1.70, p = 0.050) had shorter OS when compared to non-PPI users. Further analysis by adjusting potential confounders indicated no statistically significant differences in PFS or OS between any PPI user vs. non-PPI user groups in the dacomitinib and gefitinib arms. PPI use did not appear to affect dacomitinib exposure.ConclusionIn conclusion, PPI use in patients with NSCLC likely has minimal impact on dacomitinib or gefitinib efficacy despite decreased absorption of these drugs observed in PK studies.Trial RegistrationClinicalTrials.gov identifier, NCT01774721