Candidate mechanisms of acquired resistance to first-line osimertinib in EGFR-mutated advanced non-small cell lung cancer

PTEN-mediated resistance in cancer: From foundation to future therapies

In cancer resistance, phosphatase and tensin homolog deleted (PTEN) has emerged as a prominent protagonist. PTEN exerts its influence by regulating crucial signaling pathways that govern cell proliferation, survival, and differentiation. This comprehensive review article investigates deeply into the complex realm of PTEN-mediated drug resistance mechanisms in cancers. Our journey begins by exploring PTEN's foundational role of PTEN, unveiling its significance as a molecular conductor that intricately coordinates vital cellular pathways. We thoroughly dissected the intricate milieu of PTEN alterations, including mutations, deletions, and epigenetic silencing, and elucidated their profound implications for fueling cancer growth and evading treatment. As we navigate the complex network of PTEN, we unravel the intricate interplay between PTEN and pivotal signaling pathways, such as PI3K/AKT, MAPK/ERK, and Wnt/β-catenin, further complicating the resistance landscape. This expedition, through these intricately intertwined signaling cascades, provides insight into the multifaceted mechanisms driving resistance, thereby revealing potential exploitable weaknesses. In our quest for therapeutic strategies, we need to explore innovative approaches to restore PTEN function, encompassing genetic therapies, pharmacological agents, and precision medicines tailored to PTEN status. The concept of combination therapy has emerged as a potent tool to overcome PTEN-associated resistance, offering promising synergistic interactions with standard treatments, targeted therapies, or immunotherapy. This review offers a comprehensive overview of PTEN-mediated drug resistance mechanisms in cancer and elucidates intricate interactions within this complex landscape. This underscores the central role of PTEN in drug resistance and provides valuable insights into promising strategies with the potential to reshape the future of cancer treatment.

Current treatment landscape for patients with non-small cell lung cancer with common EGFR mutations

Common EGFR mutations including exon-19 deletions and the L858R point mutation in exon 21 constitute predominant actionable genomic alterations in individuals with non-small cell lung cancer (NSCLC). The introduction of EGFR tyrosine kinase inhibitors (TKIs) has fundamentally changed the treatment landscape for such patients by improving both progression-free survival (PFS) and overall survival (OS). Among EGFR-TKIs, third-generation agents such as osimertinib have shown marked efficacy and favorable safety profiles and have become the standard of care in the first-line setting. The combination of osimertinib with platinum-based chemotherapy has recently been shown to improve PFS compared with osimertinib monotherapy in the FLAURA2 trial. Similarly, the MARIPOSA trial demonstrated clinical benefit of the combination of the EGFR-MET bispecific antibody, amivantamab, with the third-generation EGFR-TKI, lazertinib, further supporting the use of combination therapies as first-line treatment for EGFR-mutated NSCLC. Despite these advances, however, challenges such as brain metastases remain substantial barriers to successful treatment outcomes. Management of patients with such metastases often requires a multidisciplinary approach that integrates systemic treatment with local interventions such as radiation therapy. Finally, circulating tumor DNA has emerged as a promising biomarker for real-time monitoring of treatment response and evolution of drug resistance mechanisms. Analysis of such biomarkers can facilitate dynamic and personalized therapeutic adjustments, potentially improving outcomes. This review provides a comprehensive overview of the latest clinical evidence supporting therapeutic advances in the management of EGFR-mutated NSCLC, emphasizing the importance of tailoring treatment strategies based on tumor biology, patient-specific factors, and evolving therapeutic options.

Targeting exon mutations in NSCLC: clinical insights into LAG-3, TIM-3 pathways, and advances in fourth-generation EGFR-TKIs

Lung cancer remains the second leading cause of cancer-related morbidity and mortality worldwide, with non-small cell lung cancer (NSCLC) accounting for the majority of cases. Epidermal growth factor receptor tyrosine kinase inhibitors (EGFR-TKIs) have become the standard first-line therapy for advanced NSCLC with EGFR mutations, offering significant improvements in progression-free survival (PFS), overall survival (OS), and objective response rate (ORR) compared to chemotherapy alone. Recent studies suggest that their effectiveness decreased with the emergence of acquired resistance, such as C797S and T790M. Immunotherapy alone also shows enhanced PFS and OS over chemotherapy; however, its applicability can be limited in cases with low programmed cell death ligand 1 (PD-L1) expression and result in immune-related adverse effects like those observed in retrospective, non-randomized studies. Emerging fourth-generation EGFR-TKIs, currently under clinical trials, show promising potential to address these resistance mechanisms. Advanced inhibitors, including BBT-176, BLU-945, and BLU-701, have effectively targeted resistant mutations and reduced disease progression. Studies have suggested that combining fourth-generation EGFR-TKIs with immunotherapies targeting novel pathways like LAG-3 and TIM-3 may enhance patient outcomes. Such combination regimens aim to optimize PFS, OS, and ORR while minimizing adverse effects and addressing the limitations of current therapies. This study explores the landscape of EGFR mutations, their clinical significance, and the integration of innovative fourth-generation EGFR-TKIs with immunotherapies, emphasizing the potential of precision medicine in advancing the management of EGFR-mutated NSCLC.

Evolving treatment for advanced non-small cell lung cancer harbouring common EGFR activating mutations

A clinically important subgroup of non-small cell lung cancer (NSCLC) is driven by common mutations in the epidermal growth factor receptor (EGFR). Over the past decade, first-, second-, and third-generation EGFR tyrosine kinase inhibitors (TKIs) have substantially improved clinical outcomes, although acquired resistance inevitably emerges. In particular, the third-generation TKI osimertinib has demonstrated superior progression-free survival (PFS) and overall survival (OS) compared to earlier-generation TKIs in the frontline setting, yet median OS remains approximately three years in pivotal trials. Efforts to extend disease control have led to various upfront intensification strategies, including combining EGFR TKIs with antiangiogenics or chemotherapy (e.g., the FLAURA-2 trial), and pairing novel bispecific antibodies such as amivantamab with third-generation TKIs. Upon progression on third-generation EGFR TKIs, platinum-based chemotherapy remains the standard second-line treatment, albeit with modest response rates. Emerging therapies targeting MET amplification (e.g., savolitinib plus osimertinib), leveraging antibody-drug conjugates (e.g., patritumab deruxtecan), or adding immunotherapy and antiangiogenics have shown preliminary promise in overcoming resistance. Ongoing trials are assessing optimal treatment sequencing and the use of circulating tumor DNA (ctDNA) to guide therapy escalation or de-escalation. Ultimately, the evolving landscape of EGFR-mutant NSCLC underscores the need for refined biomarker-driven approaches and personalized regimens to achieve further gains in survival. In this review, we discuss these strategies in detail, highlighting current evidence and future directions for EGFR-mutant NSCLC treatment.

Utilizing ctDNA to discover mechanisms of resistance to targeted therapies in patients with metastatic NSCLC: towards more informative trials

Advances in targeted therapies for patients with non-small-cell lung cancer have substantially improved the outcomes of those with actionable alterations in certain oncogenic driver genes. However, acquired resistance to these targeted therapies remains a major challenge. Understanding the mechanisms underlying acquired resistance will be crucial for the development of strategies that might either overcome this effect or delay the onset. Circulating tumour DNA, owing to the need for only minimally invasive sampling and a potential role as both a prognostic and predictive biomarker, is increasingly being used in both research and clinical practice. Several studies have explored the landscape of acquired resistance to targeted therapies using this approach. However, the methodologies of the published studies vary widely, and several major challenges remain in addressing the practical difficulties associated with these methods. These challenges currently limit the depth of research insight provided by the available data. In this Perspective, we review clinical reports describing the use of circulating tumour DNA to detect mechanisms of acquired resistance to targeted therapies, predominantly in patients with advanced-stage non-small-cell lung cancer, and highlight key unresolved questions with the aim of moving towards more-informative research studies.

Strategies Beyond 3rd EGFR-TKI Acquired Resistance: Opportunities and Challenges

The seminal identification of epidermal growth factor receptor (EGFR) mutations as pivotal oncogenic drivers in non-small cell lung cancer (NSCLC) has catalyzed the evolution of biomarker-guided therapeutic paradigms for advanced disease. Currently, third-generation EGFR tyrosine kinase inhibitors (EGFR-TKI) have revolutionized first-line treatment for advanced EGFR-mutated NSCLC, yet acquired resistance remains an inevitable and formidable clinical challenge. This review systematically summarizes molecular mechanisms underlying treatment resistance, with a focus on clinical challenges associated with central nervous system (CNS) metastases. Therapeutic resistance mechanisms are categorized into EGFR-dependent (on-target) pathways, typified by acquired kinase domain mutations (e.g., C797S), and EGFR-independent (off-target) pathways, involving compensatory activation of parallel signaling effectors (e.g., MET amplification, HER2 activation) or phenotypic transformation. We further evaluated contemporary diagnostic modalities for identifying resistance drivers and appraised emerging therapeutic strategies, including fourth-generation EGFR-TKI, various combination therapies, and antibody-drug conjugates (ADCs), and so forth, with emphasis on ongoing clinical trials that may transform the existing treatment paradigm. By synthesizing preclinical and clinical insights, this review aims to advance mechanistic understanding and propose therapeutic strategies to overcome acquired resistance to third-generation EGFR-TKI in first-line treatment.

Potential biomarkers of primary resistance to first- and second-generation EGFR-TKIs in non-small-cell lung cancer: a real-world study

Background

Epidermal growth factor receptor tyrosine kinase inhibitors (EGFR-TKIs) significantly improve the prognosis of EGFR-sensitive mutant non-small-cell lung cancer (NSCLC). However, the mechanisms underlying primary resistance to EGFR-TKIs remain unclear.

Objective

This study aimed to explore the biomarkers associated with primary resistance to first- and second-generation EGFR-TKIs. Primary resistance to EGFR-TKIs was defined as disease progression within 90 days (3 months) of treatment in patients with EGFR-sensitive mutant adenocarcinoma without any evidence of objective response.

Design

Retrospective, single-center study.

Methods

This study retrospectively screened patients with NSCLC who received EGFR-TKIs at Hunan Cancer Hospital from January 2018 to December 2022. According to pre-determined clinical outcomes, we divided the patients into primary resistance and sensitivity groups. Only patients with sufficient samples that passed quality control were included in this study. Tumor tissue and paired peripheral blood samples collected from patients before treatment were subjected to next-generation sequencing using an 825-gene panel. In addition, tumor tissue samples were analyzed for programmed cell death ligand 1 (PD-L1) expression.

Results

A total of 70 patients were enrolled in this study, with 35 in each of the primary resistant and sensitive groups. Patients with exon 4 mutations in the TP53 gene had significantly shorter progression-free survival (PFS) and overall survival (OS) compared to those without the mutation. PTPRD and TACC3 mutation frequencies were substantially higher in the primary resistant group and were associated with shorter PFS and OS. Furthermore, patients in the primary resistant group exhibited substantially higher levels of PD-L1 expression.

Conclusion

The potential mechanisms of primary resistance to EGFR-TKIs are highly heterogeneous. Combining some somatic variants affecting tumor function and high PD-L1 expression may contribute to this resistance.

Comparative Survival Analysis of Anti-Angiogenic Agent Plus Immunochemotherapy in NSCLC Patients After Frontline EGFR-TKI Treatment: A Retrospective Cohort Study

Advanced-stage EGFR-mutated lung non-small cell lung cancer (NSCLC) challenges current treatment paradigms, particularly after frontline EGFR-TKI therapy failure. This study investigates the survival impact of combined anti-angiogenic agent and immunochemotherapy (AICT) for this population. We retrospectively analyzed NSCLC patients at National Cheng Kung University Hospital from January 2010 to December 2022, focusing on those who had disease progression beyond frontline EGFR-TKI treatments. Survival outcomes were assessed through progression-free survival (PFS) and overall survival post-TKI failure (OSpTKI). Propensity score was employed to match patients, with Kaplan-Meier curve and multivariable Cox regression analysis determining the survival benefits. Analyses were also performed for subgroups based on PD-L1 level, treatment lines, and regimens. A total of 412 patients were enrolled, with 27 receiving AICT. Compared to patients who did not receive AICT, those who received AICT had longer PFS (5.9 vs. 3.9 months, p = 0.024) and longer OSpTKI (17.9 vs. 11.9 months, p = 0.018). The observed survival advantage in PFS and OSpTKI was consistent in both the original cohort (for PFS: hazard ratio [HR] = 0.59, 95% confidence interval [CI] = 0.39-0.90, p = 0.014; for OSpTKI: HR = 0.41, 95% CI = 0.24-0.69, p < 0.001) and after propensity score matching (for PFS: HR = 0.56, 95% CI = 0.35-0.98, p = 0.014; for OSpTKI: HR = 0.45, 95% CI = 0.26-0.79, p = 0.006). In the subgroup analyses, patients with PD-L1 ≥ 1%, those who received AICT as a second-line therapy, or those treated in conjunction with pemetrexed showed a PFS benefit. AICT improves survival outcomes in advanced-stage EGFR-mutated NSCLC, advocating for its integration into treatment regimens.

Long non-coding RNA LRTOR drives osimertinib resistance in non-small cell lung cancer by boosting YAP positive feedback loop

The therapeutic efficacy of osimertinib (OSI) in EGFR-mutant lung cancer is ultimately limited by the onset of acquired resistance, of which the mechanisms remain poorly understood. Here, we identify a novel long non-coding RNA, LRTOR, as a key driver of OSI resistance in non-small cell lung cancer (NSCLC). Clinical data indicate that elevated LRTOR expression correlates with poor prognosis in OSI-resistant patients. Functionally, LRTOR promotes tumor growth and confers OSI resistance both in vitro and in vivo. Mechanistically, LRTOR shields YAP from LATS-mediated phosphorylation at Ser127 and Ser381, preventing its proteasomal degradation. Furthermore, LRTOR facilitates the interaction between YAP and KCMF1, promoting K63-linked ubiquitination, nuclear translocation of YAP, and formation of the YAP/TEAD1 transcriptional complex, which in turn triggers the transcription of LRTOR, establishing a positive feedback loop that amplifies oncogenic signaling of YAP and consequently induces OSI resistance. LRTOR depletion by siRNA restores OSI sensitivity in resistant tumors, as demonstrated in patient-derived organoid xenograft models. Our findings unveil LRTOR as a central regulator of OSI resistance in NSCLC and propose it as a promising therapeutic and prognostic target for overcoming acquired OSI resistance in EGFR-mutant lung cancer.

Discovery and preclinical evaluations of drug candidate DA-0157 capable of overcoming EGFR drug-resistant mutation C797S and EGFR/ALK co-mutations

Activating mutations in the epidermal growth factor receptor (EGFR) and anaplastic lymphoma kinase (ALK) are significant oncogenic drivers in non-small cell lung cancer (NSCLC) patients. Despite several approved EGFR and ALK inhibitors, drug-resistant mutations pose a major challenge. Especially, there is currently no approved EGFR inhibitors targeting the C797S mutation, a refractory mutation resistant to the third-generation EGFR inhibitors. Furthermore, an increasing number of patients with EGFR/ALK co-mutations have been identified in clinical practice, yet there are no effective therapeutic options available for them. In this study, we report the discovery and preclinical evaluations of a new small-molecule drug candidate, DA-0157, which is capable of overcoming EGFR drug-resistant mutation C797S and EGFR/ALK co-mutations. DA-0157 demonstrated excellent in vitro efficacy, significantly inhibiting various EGFRC797S mutants resistant to the third-generation EGFR inhibitors, ALK rearrangements, and EGFR/ALK co-mutations. In vivo studies revealed that DA-0157 substantially inhibited tumor growth in the LD1-0025-200717 EGFRDel19/T790M/C797S PDX model (40 mg/kg/d, TGI: 98.3 %), Ba/F3-EML-4-ALK-L1196 M CDX model (40 mg/kg/d, TGI: 125.2 %), and NCI-H1975 EGFRDel19/T790M/C797S & NCI-H3122 (EML4-ALK) dual-side implantation CDX model (40 mg/kg/d, TGI: 89.5 % & 113.9 %). DA-0157 demonstrates favorable pharmacokinetic properties and safety. Currently, DA-0157 (DAJH-1050766) is undergoing Phase I/II clinical trials.

Activating Mutations in the MET Kinase Domain Co-Occur With Other Driver Oncogenes and Mediate Resistance to Targeted Therapy in NSCLC

INTRODUCTION

MET tyrosine kinase domain (TKD) mutations have recently been characterized as de novo oncogenic drivers in NSCLC. Nevertheless, whether activating MET TKD mutations can confer resistance to targeted therapy in non-MET, oncogene-driven NSCLCs remains unclear.

METHODS

To characterize the genomic features of tumors with MET TKD mutations in oncogene-driven NSCLC, we performed tumor genomic profiling on two different cohorts of patients with NSCLC. Preclinical models of the most frequently observed MET TKD mutations were generated to determine the effect on sensitivity to targeted therapy. Treatment strategies to overcome MET TKD mutation-mediated resistance were further explored.

RESULTS

Genomic profiling of more than 115,000 patients with NSCLC found that activating MET TKD mutations are prevalent in 0.15% of cases, and that about half of them co-occur with another oncogenic driver, with a differential pattern in co-occurring MET TKD mutations according to the oncogenic alteration. A review of eight cases with sequential genomic testing revealed that the MET TKD mutation was acquired after systemic therapy in 88% of cases, with a potential contribution of APOBEC mutagenesis underlying this process. In vitro, MET TKD mutation conferred resistance to targeted therapy in diverse oncogene-driven models, which could be overcome by combinatorial treatment against both the primary oncogene and the MET TKD mutation.

CONCLUSIONS

MET TKD mutation can act as an off-target resistance mechanism in diverse oncogene-driven NSCLC. Combination therapy with an effective MET-targeted therapy can potentially overcome MET TKD mutation-mediated resistance.

Transitional CXCL14+ cancer-associated fibroblasts enhance tumour metastasis and confer resistance to EGFR-TKIs, revealing therapeutic vulnerability to filgotinib in lung adenocarcinoma

BACKGROUND

The heterogeneity of cancer-associated fibroblasts (CAFs) has become a crucial focus in understanding cancer biology and treatment response, revealing distinct subpopulations with specific roles in tumor pathobiology. CAFs have also been shown to promote resistance in lung cancer cells to epidermal growth factor receptor-tyrosine kinase inhibitors (EGFR-TKIs). However, the specific CAF subsets responsible for driving tumor advancement and resistance to EGFR-TKIs in lung adenocarcinoma (LUAD) remain poorly understood.

METHODS

We integrate multiple scRNA-seq datasets to identify cell subclusters most relevant to tumor stage, patient survival, and EGFR-TKIs response. Additionally, in vitro and in vivo experiments, clinical tissue sample immunohistochemistry and patient plasma ELISA experiments are performed to validate key findings in independent LUAD cohorts.

RESULTS

By analyzing multiple scRNA-seq and spatial transcriptomic datasets, we identified a unique subset of CXCL14+ myofibroblastic CAFs (myCAFs), emerging during the early differentiation phase of pan-cancer invasiveness-associated THBS2⁺ POSTN⁺ COL11A1⁺ myCAFs. Notably, plasma levels of CXCL14 in LUAD patients correlate significantly with tumor stage. Mechanistically, this subset enhances tumor aggressiveness through epithelial-to-mesenchymal transition and angiogenesis. Among standard treatment regimens, transitional CXCL14+ myCAFs specifically confer resistance to EGFR-TKIs, while showing no significant impact on chemotherapy or immunotherapy outcomes. Through a pharmacological screen of FDA-approved drugs, we identified Filgotinib as an effective agent to counteract the EGFR-TKIs resistance conferred by this CAF subset.

CONCLUSIONS

In summary, our study highlights the role of the differentiated stage from transitional CXCL14+ myCAFs to invasiveness-associated myCAFs in driving tumor progression and therapy resistance in LUAD, positioning Filgotinib as a promising targeted therapy for this process. These insights may enhance patient stratification and inform precision treatment strategies in LUAD.

KEY POINTS

Single-cell analysis identifies transitional CXCL14+ myofibroblastic cancer-associated fibroblasts (myCAFs) predominantly exist in the advanced-stage lung adenocarcinoma (LUAD). Transitional CXCL14+ myCAFs fuel metastasis by promoting epithelial-mesenchymal transition (EMT) and angiogenesis on the spatial level. CXCL14 is a potential diagnostic marker for LUAD patients and predict the occurrence of metastasis. Transitional CXCL14+ myCAFs induce the resistance to epidermal growth factor receptor-tyrosine kinase inhibitors (EGFR-TKIs) and JAK1 inhibitor, filgotinib could reverse the effect.

Combined Use of Gefitinib and Bevacizumab in Advanced Non-Small-Cell Lung Cancer with EGFR G719S/S768I Mutations and Acquired C797S Without T790M After Osimertinib: A Case Report and Literature Review

Epidermal growth factor receptor (EGFR) tyrosine kinase inhibitors (TKIs) are effective in non-small-cell lung cancer (NSCLC) with sensitizing mutations. However, patients with uncommon EGFR mutations show variable responses, and resistance often develops. The C797S mutation is a common resistance mechanism after third-generation EGFR-TKI osimertinib therapy, with no standard treatment established. A 37-year-old Chinese woman with advanced NSCLC harboring EGFR G719S/S768I mutations developed an acquired C797S mutation without T790M after second- and third-generation EGFR-TKI therapy. She was treated with a combination of gefitinib and bevacizumab, achieving a partial response, particularly in liver metastases. Her overall survival exceeded 60 months. Gefitinib combined with bevacizumab demonstrates efficacy in managing NSCLC with uncommon EGFR mutations and overcoming acquired C797S resistance. This combination therapy offers a promising treatment strategy for patients with limited options after resistance to second- and third-generation EGFR-TKIs.

Strategies to Overcome Resistance to Osimertinib in EGFR-Mutated Lung Cancer

Non-small-cell lung cancer (NSCLC) represents the most common type of lung cancer. The majority of patients with lung cancer characterized by activating mutations in the epidermal growth factor receptor (EGFR), benefit from therapies entailing tyrosine kinase inhibitors (TKIs). In this regard, osimertinib, a third-generation EGFR TKI, has greatly improved the outcome for patients with EGFR-mutated lung cancer. The AURA and FLAURA trials displayed the superiority of the third-generation TKI in both first- and second-line settings, making it the drug of choice for treating patients with EGFR-mutated lung cancer. Unfortunately, the onset of resistance is almost inevitable. On-target mechanisms of resistance include new mutations (e.g., C797S) in the kinase domain of EGFR, while among the off-target mechanisms, amplification of MET or HER2, mutations in downstream signaling molecules, oncogenic fusions, and phenotypic changes (e.g., EMT) have been described. This review focuses on the strategies that are currently being investigated, in preclinical and clinical settings, to overcome resistance to osimertinib, including the use of fourth-generation TKIs, PROTACs, bispecific antibodies, and ADCs, as monotherapy and as part of combination therapies.

Exploring the Expression of CD73 in Lung Adenocarcinoma with EGFR Genomic Alterations

BACKGROUND/OBJECTIVES

Immune checkpoint inhibitors (ICIs) benefit some lung cancer patients, but their efficacy is limited in advanced lung adenocarcinoma (LUAD) with EGFR mutations (EGFRm), largely due to a non-immunogenic tumour microenvironment (TME). Furthermore, EGFRm LUAD patients often experience increased toxicity with ICIs. CD73, an ectonucleotidase involved in adenosine production, promotes tumour immune evasion and could represent a novel therapeutic target. This study investigates CD73 expression in LUAD with EGFR alterations and its clinico-pathological correlations.

METHODS

CD73 expression in tumour (CD73TC) and stromal (CD73SC) cells was assessed in 76 treatment-naive LUAD patients using immunohistochemistry (IHC) (D7F9A clone) alongside IHC PD-L1 (22C3 clone). EGFR alterations were identified by molecular sequencing and FISH. Event-free survival (EFS) was analysed based on CD73TC expression.

RESULTS

CD73TC expression was observed in 66% of cases, with high expression (Tumour Proportion Score > 50%) correlating with improved EFS (p = 0.045). CD73TC and PD-L1 expression were not significantly correlated (p = 0.44), although a weak inverse trend was observed. CD73SC expression was detected in 18% of cases, predominantly in early-stage (p = 0.037), PD-L1-negative (p = 0.030), and non-EGFR-amplified (p = 0.0018) tumours. No significant associations were found with disease stage, histological subtype, EGFR mutation type, and amplification.

CONCLUSIONS

CD73 expression in EGFRm LUAD is heterogeneous and associated with diverse TME profiles. These findings support the potential of CD73 as a predictive biomarker and therapeutic target, highlighting its clinical relevance in EGFRm LUAD.

Chromosomal Instability Is Associated with cGAS-STING Activation in EGFR-TKI Refractory Non-Small-Cell Lung Cancer

Epidermal growth factor receptor tyrosine kinase inhibitors (EGFR-TKIs) are standard therapies for EGFR-mutated non-small-cell lung cancer (NSCLC); however, their efficacy is inconsistent. Secondary mutations in the EGFR or other genes that lead to resistance have been identified, but resistance mechanisms have not been fully identified. Chromosomal instability (CIN) is a hallmark of cancer and results in genetic diversity. In this study, we demonstrated by transcriptomic analysis that CIN activates the cGAS-STING signaling pathway, which leads to EGFR-TKI refractoriness in a subset of EGFR-mutated NSCLC patients. Furthermore, EGFR-mutated H1975dnMCAK cells, which frequently underwent chromosomal mis-segregation, demonstrated refractoriness to the EGFR-TKI osimertinib compared to control cells. Second, H1975dnMCAK cells exhibited activation of cGAS-STING signaling and its downstream signaling, including tumor-promoting cytokine IL-6. Finally, chromosomally unstable EGFR-mutated NSCLC exhibited enhanced epithelial-mesenchymal transition (EMT). Blockade of cGAS-STING-TBK1 signaling reversed EMT, resulting in restored susceptibility to EGFR-TKIs in vitro and in vivo. These results suggest that CIN may lead to the activation of cGAS-STING signaling in some EGFR-mutated NSCLC, resulting in EMT-associated EGFR-TKI resistance.

NLRP4 unlocks an NK/macrophages-centered ecosystem to suppress non-small cell lung cancer

BACKGROUND

Tumor immune evasion extends beyond T cells, affecting innate immune elements like natural killer cells (NK) and macrophages within the tumor-immune microenvironment (TIME). Nevertheless, translational strategies to trigger collaboration of NK cells and macrophages to initiate sufficient anti-tumor cytoxicity remain scarce and are urgently needed.

METHODS

In this study, TCGA datasets was used to confirm the prognosis value of the expression level of NLR family pyrin domain containing 4 (NLRP4) in NSCLC and the tumor tissues microarray was used to further check its clinical-relevance at protein-level. Subsequently, a tumor cell line with stable NLRP4 overexpression was established and subcutaneous tumor models in C57BL/6J mice were used to validate the anti-tumor characteristics of NLRP4. After analyzing the tumor microenvironment using flow cytometry and multiplex immunofluorescence, we further validated our findings through co-culture transwell assays and TCGA analysis. Utilizing bulk-RNA sequencing, proteomics, and mass spectrometry of mouse tumor tissues, we innovatively identified the downstream pathways of NLRP4 and verified them through co-immunoprecipitation (co-IP) and Western blot (WB) experiments.

RESULTS

NLRP4 could trigger a distinct anti-tumor ecosystem organized by TIGIT+TNFA+ NK and iNOS+ M1 in lung cancer, discovered in TCGA analysis and verified in murine model. NLRP4-eco exerted tumor-suppression capacity through chemokine reprogramming including CCL5 and CXCL2. Meanwhile, the cytoxicity of NK could be facilitated by iNOS+M1. Mechanistically, NLRP4 stimulated PI3K/Akt-NF-kB axis through suppression of the activity of PP2A. Besides, knockdown of CCL5 and blockade of CXCL2-CXCR2 axis abolished chemotaxis of TIGIT+TNFA+ NK and iNOS+ M1 respectively, as well as for LB-100, a PP2A inhibitor.

CONCLUSION

Altogether, we delineated NLRP4's unexplored facets and discovered an NLRP4-driven anti-tumor ecosystem composed of TIGIT+TNFA+ NK and iNOS+ M1. Finally, targeting PP2A by its inhibitor successfully mimicked the anti-tumor capacity of the overexpression of NLRP4.

CD105 blockade restores osimertinib sensitivity in drug-resistant EGFR-mutant non-small cell lung cancer

AIM

To investigate the role of CD105 in mediating drug resistance to EGFR-targeted therapy in non-small cell lung cancer (NSCLC).

METHODS

Imaging mass cytometry was conducted on 66 NSCLC tumors, 44 of which had EGFR mutations. We correlated clinical variables, including overall survival, with CD105 (endoglin) expression, a co-receptor for bone morphogenetic protein (BMP) signaling. Two osimertinib-resistant EGFR-mutant cell lines were developed to study the effects of EGFR and CD105 disruption. Single cell RNA sequencing of the isogenic parental and osimertinib resistant lines was performed. Additionally, ATAC sequencing and Single Cell ENergetIc metabolism by profiling Translation inHibition analysis (SCENITH) was used to assess promoter chromatin status and glycolytic state.

RESULTS

We found a negative correlation between CD105 expression and overall survival in patients. Treatment with osimertinib or EGFR knockdown significantly elevated CD105 expression in EGFR-mutant cell lines. Single-cell RNA sequencing identified a subset of cells with heightened endothelial characteristics and altered pyrimidine metabolism, associated with osimertinib resistance. These cells exhibited a slow-cycling behavior, characterized by elevated chromatin condensation and reduced glycolysis. Combining osimertinib with carotuximab, a CD105 neutralizing antibody, significantly reduced the slow-cycling transcriptomic signature, increased chromatin accessibility, and restored glycolysis compared to osimertinib treatment alone. Mass spectrometry confirmed that carotuximab re-engaged EGFR signaling by coupling it with CD105. Consequently, carotuximab re-sensitized resistant tumors to osimertinib by increasing their mitotic index and ERK signaling in mouse models.

CONCLUSION

Carotuximab effectively reduced the slow-cycling cell population and restored osimertinib sensitivity, offering a promising strategy for managing refractory NSCLC.

A phase II trial of mTORC1/2 inhibition in STK11 deficient non small cell lung cancer

There are no current stratified medicine options for STK11-deficient NSCLC. STK11 loss mediates mTORC activation, GLUT1 up-regulation and increased glycolysis. This metabolic reprogramming might represent a therapeutic vulnerability targetable with mTORC1/2 inhibition. In arm B2 of the National Lung Matrix Trial 54 patients with NSCLC received vistusertib, of which 49 were STK11-deficient (30 with KRAS mutation (B2D), 19 without (B2S)). Objective response (OR) and durable clinical benefit (DCB) rates with 95% credible intervals (CrI) were estimated from posterior probability distributions generated using Bayesian beta-binomial conjugate analysis. In B2D, 2 per-protocol patients obtained OR (estimated true OR rate (95%CrI) 9.8% (2.4-24.3). Estimates of true DCB rate (95%CrI): B2D 24.4% (11.1-42.3), B2S 14.6% (3.6-34.7). Overall, vistusertib cannot be recommended in this context. Longitudinal ctDNA analysis demonstrates enrichment of SMARCA4 mutations post-treatment. In vitro studies show adaptive resistance to mTORC1/2 inhibition via AKT reactivation. (NCT02664935, ISRCTN38344105, EudraCT 2014-000814-73, 10 June 2015).

Emerging molecular testing paradigms in non-small cell lung cancer management-current perspectives and recommendations

Advances in molecular testing and precision oncology have transformed the clinical management of lung cancer, especially non-small cell lung cancer, enhancing diagnosis, treatment, and outcomes. Practical guidelines offer insights into selecting appropriate biomarkers and assays, emphasizing the importance of comprehensive testing. However, real-world data reveal the underutilization of biomarker testing and consequently targeted therapies. Molecular testing often occurs late in diagnosis or not at all in clinical practice, leading to delayed or inadequate treatment. Enhancing precision requires adherence to best practices by all health care professionals involved, which can ultimately improve lung cancer patient outcomes. The future of precision oncology for lung cancer will likely involve a more personalized approach, starting increasingly from earlier disease settings, with novel and more complex targeted therapies, immunotherapies, and combination regimens, and relying on liquid biopsies, muti-detection advanced genomic technologies and data integration, with artificial intelligence as a central orchestrator. This review presents the currently known actionable mutations in lung cancer and new upcoming ones that are likely to enter clinical practice soon and provides an overview of established and emerging concepts in testing methodologies. Challenges are discussed and best practice recommendations are made that are relevant today, will continue to be relevant in the future, and are likely to be relevant for other cancer types too.

CRISPR-dCas9-Mediated PTEN Activation via Tumor Cell Membrane-Coated Nanoplatform Enhances Sensitivity to Tyrosine Kinase Inhibitors in Nonsmall Cell Lung Cancer

EGFR tyrosine kinase inhibitors (EGFR-TKIs) have garnered substantial clinical success in treating nonsmall cell lung cancer (NSCLC) harboring epidermal growth factor receptor (EGFR) mutations. However, the inevitable emergence of drug resistance, frequently attributed to activation, mutation, or deletion of multiple signaling pathways, poses a significant challenge. Notably, the loss of PTEN protein expression has emerged as a pivotal mechanism fostering resistance in EGFR mutant lung cancers. Consequently, strategies aimed at upregulating PTEN expression hold great promise for restoring drug sensitivity. Leveraging the versatility, precision, and efficacy of nuclease-deactivated Cas9 (dCas9) as a transcriptional activator, we designed a CRISPR-dCas9 system to stimulate PTEN expression. To further enhance target specificity and drug delivery efficiency, we innovatively harnessed the tumor cell membrane (CCM) as a homologous targeting surface coating for our vector, thereby creating a targeted activation nanoplatform. Comprehensive in vitro and in vivo evaluations demonstrated that the synergistic interplay between gefitinib and the CRISPR-dCas9 system significantly enhanced drug sensitivity. The finding underscores the potential of our approach in addressing the issue of lung cancer resistance, offering a promising avenue for personalized and effective cancer therapies.

L858R/L718Q and L858R/L792H Mutations of EGFR Inducing Resistance Against Osimertinib by Forming Additional Hydrogen Bonds

Acquired resistance to first-line treatments in various cancers both promotes cancer recurrence as well as limits effective treatment. This is true for epidermal growth factor receptor (EGFR) mutations, for which secondary EGFR mutations are one of the principal mechanisms conferring resistance to the covalent inhibitor osimertinib. Thus, it is very important to develop a deeper understanding of the secondary mutational resistance mechanisms associated with EGFR mutations arising in tumors treated with osimertinib to expedite the development of innovative therapeutic drugs to overcome acquired resistance. This work uses all-atom molecular dynamics (MD) simulations to investigate the conformational variation of two reported EGFR mutants (L858R/L718Q and L858R/L792H) that resist osimertinib. The wild-type EGFR kinase domain and the L858R mutant are used as the reference. Our MD simulation results revealed that both the L718Q and L792H secondary mutations induce additional hydrogen bonds between the residues in the active pocket and the residues with the water molecules. These additional hydrogen bonds reduce the exposure area of C797, the covalent binding target of osimertinib. The additional hydrogen bonds also influence the binding affinity of the EGFR kinase domain by altering the secondary structure and flexibility of the amino acid residues in the domain. Our work highlights how the two reported mutations may alter both residue-residue and residue-solvent hydrogen bonds, affecting protein binding properties, which could be helpful for future drug discovery.

Evolution of first versus next-line targeted therapies for metastatic non-small cell lung cancer

The expanding armamentarium of targeted therapies has revolutionized treatment for metastatic oncogene-addicted lung cancers. For multiple subsets, such as those harboring EGFR mutations and fusions in ALK or ROS1, successive generation of increasingly potent, selective, and brain-penetrating targeted therapies have shifted the treatment paradigm towards preferential first-line use of next-generation drugs. This evolution in clinical practice provides a lens through which to review the lessons learned from drug development in oncogene-addicted lung cancers, guided by translational insights into tumor biology and mechanisms of therapeutic resistance. For oncogenic drivers that are less sensitive to single-agent targeted therapies, rationally designed combination strategies will be needed to enable first-line use of targeted agents.

Design, Synthesis and Evaluation of Novel Cyclopropanesulfonamide Derivatives for the Treatment of EGFRC797S Mutation in Non-Small Cell Lung Cancer

Background

The 797S mutation in EGFR disrupts the covalent binding of third-generation inhibitors, causing drug resistance. Currently, no clinically drug fully overcomes this resistance.

Methods

We designed and synthesised a novel EGFR C797S-targeted inhibitor-5d by introducing structures such as cyclopropyl and sulfonamide with Brigatinib as the lead compound; we identified the target of action by ELISA and molecular docking, and tested its anti-tumor activity and safety in vivo and vitro, as well as its effects on cell cycle, apoptosis and DNA damage.

Results

It was found that there were 10 new small-molecule inhibitors and compound 5d was identified as highly selective with low toxicity. WB confirmed 5d's inhibition of EGFR and m-TOR pathways. Mechanistic studies revealed 5d induced cell cycle arrest in G2/M phase caused DNA damage and cell apoptosis, increasing apoptotic protein cleaved caspase-3 levels. It also inhibited growth in PC9 cells with an EGFRdel19 mutation. Importantly, 5d also demonstrated superior anti-tumor activity in vivo and was superior to the positive control Brigatinib.

Conclusion

We concluded that cyclopropylsulfonamide 5d derivatives induce cell cycle arrest, apoptosis, and DNA damage by regulating tumor-related genes, thereby inhibiting the proliferation of C797S mutated lung cancer cells.

Rational Design of a Potent, Selective, and Metabolically Stable CDK9 Inhibitor to Counteract Osimertinib Resistance through Mcl-1 Suppression and Enhanced BRD4 Co-Targeting

Overcoming osimertinib resistance in NSCLC treatment remains a significant clinical challenge. CDK9 has emerged as a promising target due to its critical role in sustaining oncogenic transcriptional programs, particularly via Mcl-1 regulation. Herein, we report the structure-guided optimization of a previously identified CDK9 inhibitor (Z11), resulting in the discovery of T7, a potent, selective, and metabolically stable candidate (IC50 = 1.2 nM). T7 effectively suppressed cell proliferation, reduced colony formation, and induced apoptosis in Osimertinib-resistant NSCLC cells by downregulating Mcl-1. Furthermore, T7 significantly inhibited the growth of resistant organoids and demonstrated marked antitumor efficacy in a xenograft model. Notably, combining T7 with the BRD4 inhibitor JQ1 further enhanced antitumor activity both in vitro and in vivo, revealing a complementary therapeutic strategy. These findings identify T7 as a promising next-generation CDK9 inhibitor for addressing Osimertinib resistance in NSCLC and underscore the potential of transcriptional cotargeting approaches to improve clinical outcomes.

Mesenchymal Stem Cell-Derived Exosomes in Cancer Resistance Against Therapeutics

Mesenchymal stem cells (MSCs) are specialized cells that can differentiate into various types of cells. MSCs can be utilized to treat cancer. However, a MSC is considered a double-edged sword, because it can promote tumor progression and support cancer cell growth. Likewise, MSC-derived exosomes (MSC-Exos) carry various intracellular materials and transfer them to other cells. MSC-Exos could also cause tumor progression, including brain cancer, breast cancer, hepatic cancer, lung cancer, and colorectal cancer, and develop resistance against therapies, mainly chemotherapy, radiotherapy, and immunotherapy. An MSC-Exo promotes tumor development and causes drug resistance in various cancer types. The mechanisms involved in cancer drug resistance vary depending on the cancer cell heterogeneity and complexity. In this article, we have explained the various biomarkers and mechanisms involved in the tumor and resistance development through MSC-Exos in different cancer types.

Drug Resistance in Late-Stage Epidermal Growth Factor Receptor (EGFR)-Mutant Non-Small Cell Lung Cancer Patients After First-Line Treatment with Tyrosine Kinase Inhibitors

The development of tyrosine kinase inhibitors (TKIs) for late-stage epidermal growth factor receptor (EGFR)-mutant non-small cell lung cancer (NSCLC) represented a drastic change in the treatment of late-stage lung cancer. Drug resistance develops after a certain period of first-line TKI treatment, which has led to decades of changing treatment guidelines for EGFR-mutant NSCLC. This study discussed the potential mechanisms of drug resistance against first-line TKI treatment and potential successive treatment strategies. Next-generation sequencing (NGS) may play a role in the evaluation of drug resistance in first-line TKI treatment. Emerging combination regimens and ongoing trials were discussed. Potential future strategies for treatment and for the management of drug resistance were proposed in this study.

Application of an Integrated Single-Cell and Three-Dimensional Spheroid Culture Platform for Investigating Drug Resistance Heterogeneity and Epithelial-Mesenchymal Transition (EMT) in Lung Cancer Subclones

Lung cancer is a leading cause of cancer-related mortality worldwide, largely due to its heterogeneity and intrinsic drug resistance. Malignant pleural effusions (MPEs) provide diverse tumor cell populations ideal for studying these complexities. Although chemotherapy and targeted therapies can be initially effective, subpopulations of cancer cells with phenotypic plasticity often survive treatment, eventually developing resistance. Here, we integrated single-cell isolation and three-dimensional (3D) spheroid culture to dissect subclonal heterogeneity and drug responses, aiming to inform precision medicine approaches. Using A549 lung cancer cells, we established a cisplatin-resistant line and isolated three resistant subclones (Holoclone, Meroclone, Paraclone) via single-cell sorting. In 3D spheroids, Docetaxel and Alimta displayed higher IC50 values than in 2D cultures, suggesting that 3D models better reflect clinical dosing. Additionally, MPE-derived Holoclone and Paraclone subclones exhibited distinct sensitivities to Giotrif and Capmatinib, revealing their heterogeneous drug responses. Molecular analyses confirmed elevated ABCB1, ABCG2, cancer stem cell (CSC) markers (OCT4, SOX2, CD44, CD133), and epithelial-mesenchymal transition (EMT) markers (E-cadherin downregulation, increased Vimentin, N-cadherin, Twist) in resistant subclones, correlating with enhanced migration and invasion. This integrated approach clarifies the interplay between heterogeneity, CSC/EMT phenotypes, and drug resistance, providing a valuable tool for predicting therapeutic responses and guiding personalized, combination-based lung cancer treatments.

A rare epidermal growth factor receptor T790M/cis-C797S/L718Q compound mutation in a lung adenocarcinoma patient who did not derive any benefit from combination therapy with afatinib and bevacizumab

The most common mutations in epidermal growth factor receptor (EGFR) are exon 19 deletions and exon 21 L858R mutations, both of which respond effectively to EGFR tyrosine kinase inhibitors. However, the efficacy of EGFR tyrosine kinase inhibitors against rare EGFR mutations remains controversial. Many patients eventually develop resistance to EGFR tyrosine kinase inhibitors. Here, we encountered the case of a 62-year-old male with lung adenocarcinoma and a history of hypertension, who harbored a rare EGFR L858R/T790M/cis-C797S/L718Q compound mutation and showed resistance to osimertinib. The patient showed a partial response to treatment with a combination of afatinib and bevacizumab lasting 2 months. Although this case did not demonstrate a clear benefit from dual therapy with afatinib and bevacizumab, it provides a valuable therapeutic reference for patients with rare compound EGFR mutations and offers insights for future studies.

Targeting the Tumor Microenvironment in EGFR-Mutant Lung Cancer: Opportunities and Challenges

Tyrosine kinase inhibitors (TKIs) have transformed the treatment of epidermal growth factor receptor (EGFR)-mutant non-small cell lung cancer. However, treatment resistance remains a major challenge in clinical practice. The tumor microenvironment (TME) is a complex system composed of tumor cells, immune and non-immune cells, and non-cellular components. Evidence indicates that dynamic changes in TME during TKI treatment are associated with the development of resistance. Research has focused on identifying how each component of the TME interacts with tumors and TKIs to understand therapeutic targets that could address TKI resistance. In this review, we describe how TME components, such as immune cells, fibroblasts, blood vessels, immune checkpoint proteins, and cytokines, interact with EGFR-mutant tumors and how they can promote resistance to TKIs. Furthermore, we discuss potential strategies targeting TME as a novel therapeutic approach.

Possibilities of Overcoming Resistance to Osimertinib in NSCLC Patients with Mutations in the EGFR Gene

The advancement of genetic research has changed the treatment management of non-small cell lung cancer (NSCLC) and opened the era of personalized medicine. Currently, three generations of EGFR tyrosine kinase inhibitors (TKIs) are used in the treatment of NSCLC patients with activating mutations in the EGFR gene, and ongoing clinical trials examine the safety and effectiveness of new third and fourth generations. Osimertinib, a third generation of TKIs that binds irreversibly to abnormal tyrosine kinase, may be applied in various indications in patients with NSCLC: (i) in the second and subsequent lines of therapy in patients with resistance to first-generation or second-generation EGFR TKIs, (ii) in the first line of treatment in monotherapy in NSCLC patients with frequent or rare EGFR mutations, (iii) in combination with chemotherapy in patients with locally advanced or metastatic NSCLC with frequent EGFR mutations, (iv) in consolidation therapy in patients with locally advanced NSCLC who had previously received chemoradiotherapy, (v) in adjuvant treatment of NSCLC patients with stage IB-IIIA undergoing radical surgical resection. Despite the high efficacy of osimertinib in NSCLC patients harboring EGFR mutations, resistance driven in EGFR-dependent or EGFR-independent mechanisms may occur. Since resistance to osimertinib is poorly understood, the following review presents the overview of resistance mechanisms to osimertinib, methodological approaches for the resistance diagnosis, and the up-to-date treatment possibilities for overcoming the resistance process.

Afatinib and Necitumumab in EGFR-Mutant NSCLC with Acquired Resistance to Tyrosine Kinase Inhibitors

Introduction

Although tyrosine kinase inhibitors (TKIs) are effective against NSCLC harboring sensitizing EGFR gene mutations, acquired resistance is inevitable. Preclinical studies suggest that combining EGFR TKI and monoclonal antibody therapies may have activity in EGFR-mutated NSCLC that has progressed on TKI therapy alone. Therefore, we prospectively evaluated afatinib plus necitumumab in patients with EGFR-mutated NSCLC.

Methods

This was a phase 1, dose-escalation, dose-expansion trial assessing the safety and efficacy of afatinib plus necitumumab. Patients had advanced or metastatic EGFR-mutated NSCLC with progression after (1) first-generation TKI if T790M negative, (2) subsequent line third-generation TKI if T790M positive, or (3) third-generation TKI in the first-line setting. Dose-escalation followed a 3+3 design. The primary end point of dose-expansion was objective response rate.

Results

A total of 22 patients with EGFR-mutated NSCLC were enrolled. The maximum tolerated dose was afatinib 40 mg oral daily plus necitumumab 600 mg intravenous on days 1 and 15 every 28 days. There were no grade 4 to 5 adverse events observed, and seven patients (32%) experienced grade 3 treatment-related adverse events (three rash; one each oral mucositis, diarrhea, headache, ventricular arrhythmia, and tachycardia). In the entire cohort, there were no responses observed, the median progression-free survival was 1.8 months, and the disease control rate was 36% but varied between the subgroups.

Conclusions

Afatinib plus necitumumab was safe but had limited activity in patients with EGFR-mutated NSCLC. Biomarker studies may identify patient subgroups that are more likely to benefit.

The changing treatment landscape of EGFR-mutant non-small-cell lung cancer

The discovery of the association between EGFR mutations and the efficacy of EGFR tyrosine-kinase inhibitors (TKIs) has revolutionized the treatment paradigm for patients with non-small-cell lung cancer (NSCLC). Currently, third-generation EGFR TKIs, which are often characterized by potent central nervous system penetrance, are the standard-of-care first-line treatment for advanced-stage EGFR-mutant NSCLC. Rational combinations of third-generation EGFR TKIs with anti-angiogenic drugs, chemotherapy, the EGFR-MET bispecific antibody amivantamab or local tumour ablation are being investigated as strategies to delay drug resistance and increase clinical benefit. Furthermore, EGFR TKIs are being evaluated in patients with early stage or locally advanced EGFR-mutant NSCLC, with the ambitious aim of achieving cancer cure. Despite the inevitable challenge of acquired resistance, emerging treatments such as new TKIs, antibody-drug conjugates, new immunotherapeutic approaches and targeted protein degraders have shown considerable promise in patients with progression of EGFR-mutant NSCLC on or after treatment with EGFR TKIs. In this Review, we describe the current first-line treatment options for EGFR-mutant NSCLC, provide an overview of the mechanisms of acquired resistance to third-generation EGFR TKIs and explore novel promising treatment strategies. We also highlight potential avenues for future research that are aimed at improving the survival outcomes of patients with this disease.

A Novel DNA Repair-Gene Model to Predict Responses to Immunotherapy and Prognosis in Patients With EGFR-Mutant Non-Small Cell Lung Cancer

BACKGROUND

The epidermal growth factor receptor mutant (EGFRm) non-small cell lung cancer (NSCLC) has a unique "cold" immune profile. DNA damage repair (DDR) genes are closely related to tumorigenesis and the effectiveness of immunotherapy in many tumors. However, the role and mechanism of DDR in the genesis and progression of EGFRm NSCLC remain unclear.

METHODS

This study included 101 EGFRm NSCLC samples from The Cancer Genome Atlas (TCGA) dataset and a GSE31210 dataset (external set) from the GEO database. Cluster analysis was used to identify different subtypes of EGFRm NSCLC based on the expression of DDR genes. Univariate and LASSO regression analysis was used to develop a DDR-based predictive model. The prognostic significance of this model was assessed using Cox regression, Kaplan-Meier, and receiver operating characteristic (ROC) curve analyses. Bioinformatics analysis was performed to investigate the clinicopathological characteristics and immune profiles associated with this model. In vitro experiment was performed to testify the role of DDR genes in EGFRm NSCLC.

RESULTS

We identified two subtypes of EGFRm NSCLC: DDR-activated and DDR-suppressed. The DDR-activated subtype showed more aggressive clinical behavior and poorer prognosis and was more responsive to immunotherapy. A prognostic model for EGFRm NSCLC was constructed using four DDR genes: CAPS, FAM83A, IGLV8-61, and SLC7A5. The derived risk score could serve as an independent prognostic indicator. High- and low-risk patients exhibited distinct clinicopathological characteristics, immune profiles, and responses to immunotherapy. The T-cell inflammation and Tumor Immune Dysfunction and Exclusion (TIDE) scores differed between the high- and low-risk subgroups, with both showing enhanced effectiveness of immunotherapy in the low-risk subgroup. Targeted therapy such as BI.2536, an inhibitor of polo-like kinase 1, could be effective for patients with high-risk EGFRm NSCLC. Meanwhile, in vitro detection approved the role of DDR genes in EGFRm NSCLC response.

CONCLUSION

This study demonstrated a diversity of DDR genes in EGFRm NSCLC and developed a predictive model using these genes. This model could assist in identifying potential candidates for immunotherapy and in assessing personalized treatment and prognosis of patients with EGFRm NSCLC.

Optimizing Osimertinib for NSCLC: Targeting Resistance and Exploring Combination Therapeutics

Non-small-cell lung cancer (NSCLC) is a leading cause of cancer-related deaths worldwide, with epidermal growth factor receptor (EGFR) mutations present in a substantial proportion of patients. Third-generation EGFR tyrosine kinase inhibitors (EGFR TKI), exemplified by osimertinib, have dramatically improved outcomes by effectively targeting the T790M mutation-a primary driver of acquired resistance to earlier-generation EGFR TKI. Despite these successes, resistance to third-generation EGFR TKIs inevitably emerges. Mechanisms include on-target mutations such as C797S, activation of alternative pathways like MET amplification, histologic transformations, and intricate tumor microenvironment (TME) alterations. These resistance pathways are compounded by challenges in tolerability, adverse events, and tumor heterogeneity. In light of these hurdles, this review examines the evolving landscape of combination therapies designed to enhance or prolong the effectiveness of third-generation EGFR TKIs. We explore key strategies that pair osimertinib with radiotherapy, anti-angiogenic agents, immune checkpoint inhibitors, and other molecularly targeted drugs, and we discuss the biological rationale, preclinical evidence, and clinical trial data supporting these approaches. Emphasis is placed on how these combinations may circumvent diverse resistance mechanisms, improve survival, and maintain a favorable safety profile. By integrating the latest findings, this review aims to guide clinicians and researchers toward more individualized and durable treatment options, ultimately enhancing both survival and quality of life for patients with EGFR-mutated NSCLC.

MET Activation in Lung Cancer and Response to Targeted Therapies

The hepatocyte growth factor receptor (MET) is a receptor tyrosine kinase (RTK) that mediates the activity of a variety of downstream pathways upon its activation. These pathways regulate various physiological processes within the cell, including growth, survival, proliferation, and motility. Under normal physiological conditions, this allows MET to regulate various development and regenerative processes; however, mutations resulting in aberrant MET activity and the consequent dysregulation of downstream signaling can contribute to cellular pathophysiology. Mutations within MET have been identified in a variety of cancers and have been shown to mediate tumorigenesis by increasing RTK activity and downstream signaling. In lung cancer specifically, a number of patients have been identified as possessing MET alterations, commonly receptor amplification (METamp) or splice site mutations resulting in loss of exon 14 (METex14). Due to MET's role in mediating oncogenesis, it has become an attractive clinical target and has led to the development of various targeted therapies, including MET tyrosine kinase inhibitors (TKIs). Unfortunately, these TKIs have demonstrated limited clinical efficacy, as patients often present with either primary or acquired resistance to these therapies. Mechanisms of resistance vary but often occur through off-target or bypass mechanisms that render downstream signaling pathways insensitive to MET inhibition. This review provides an overview of the therapeutic landscape for MET-positive cancers and explores the various mechanisms that contribute to therapeutic resistance in these cases.

Longitudinal genomic profiling using liquid biopsies in metastatic nonsquamous NSCLC following first line immunotherapy

Tumor genomic profiling is often limited to one or two timepoints due to the invasiveness of tissue biopsies, but longitudinal profiling may provide deeper clinical insights. Using ctDNA data from IMpower150 study, we examined genetic changes in metastatic non-squamous NSCLC post-first-line immunotherapy. Mutations were most frequently detected in TP53, KRAS, SPTA1, FAT3, and LRP1B at baseline and during treatment. Mutation levels rose prior to radiographic progression in most progressing patients, with specific mutations (SPTA1, STK11, KEAP1, SMARCA4, TBX3, CDH2, and MLL3) significantly enriched in those with progression or nondurable response. However, ctDNA's role in detecting hyperprogression and pseudoprogression remains uncertain. STK11, SMARCA4, KRAS, SLT2, and KEAP1 mutations showed the strongest correlation with poorer overall survival, while SMARCA4, STK11, SPTA1, TBX3, and KEAP1 mutations correlated with shorter progression-free survival. Overall, longitudinal liquid biopsy profiling provided valuable insights into lung cancer biology post-immunotherapy, potentially guiding personalized therapies and future drug development.

Real-World Outcomes of Pralsetinib in RET Fusion-Positive NSCLC

Introduction

Pralsetinib is a RET inhibitor found to have antitumor activity in advanced, metastatic, RET fusion-positive NSCLC.

Objective

To assess real-world efficacy of pralsetinib and treatment sequences in patients with RET fusion-positive NSCLC.

Design

Retrospective study of consecutive patients enrolled in the French expanded-access program for pralsetinib from December 1, 2019, to December 31, 2021.

Participants

A total of 41 patients with advanced, refractory, RET fusion-positive NSCLC were included. Pralsetinib was administered at a daily dose of 400 mg based on safety and pharmacokinetic outcomes from previous phase 1/2 study.

Results

Pralsetinib was administered as second line in 23 patients (56%) and as third line and beyond in 15 patients (37%). After a median follow-up of 26.3 months, pralsetinib was ongoing in 13 patients. Median real-world progression-free survival was 11.8 (95% confidence interval [CI]: 9.3-15.5) months. Objective response rate was 68% (95% CI: 50%-82%), and disease control rate was 89% (95% CI: 75%-97%). Subsequent line of systemic therapy was initiated in 11 patients. Median overall survival from pralsetinib initiation was 23.8 (95% CI: 16.5-not reached) months.

Conclusion

In this extensive real-world cohort of patients with advanced or metastatic NSCLC harboring RET fusions, we highlight the antitumor efficacy of pralsetinib, particularly when administered in later treatment lines. We also observe the aggressive nature of disease progression, frequent utilization of chemotherapy and antiangiogenic agents as initial subsequent therapies, and limited insight into resistance mechanisms due to infrequent rebiopsy and genomic profiling at progression.

The efficacy of continuing osimertinib with platinum pemetrexed chemotherapy upon progression in patients with metastatic non-small cell lung cancer harboring sensitizing EGFR mutations

INTRODUCTION

For patients with EGFR mutant NSCLC who progress on osimertinib, the clinical benefit of continuing osimertinib with next line platinum pemetrexed chemotherapy remains unknown.

METHODS

In this international, multi-center, retrospective cohort study, a total of 159 patients with EGFR mutant NSCLC who progressed on osimertinib and received platinum-pemetrexed therapy on progression from 2013 to 2023 were included. The data cutoff was December 31, 2023. Data analysis was conducted from January 2024 to June 2024. The primary endpoints were progression free survival (PFS) and overall survival (OS), analyzed using Kaplan-Meier methods. Multivariable Cox regression adjusting for patient-specific and cancer-specific factors was performed.

RESULTS

421 patients with EGFR mutant NSCLC with progression on osimertinib were identified, of which159 patients who met pre-specified inclusion criteria were divided into two groups: Cohort 1 (osimertinib + platinum-pemetrexed) included 50 patients (median [IQR] age, 59 [30 - 83] years; 36 [72.0 %] female; 11 [22.4 %] Asian) and Cohort 2 (platinum-pemetrexed alone) included 109 patients (median [IQR] age, 54 [25 - 80] years; 62 [56.9 %] female; 74 [64.9 %] Asian). Most patients were never smokers (Cohort 1, 37 [74.0 %]; Cohort 2, 66 [60.6 %]). One third of patients had baseline brain metastases (Cohort 1, 19 [38.0 %]; Cohort 2, 36 [38.3 %]). Both cohorts had a median of two prior lines of anti-cancer therapy. The addition of bevacizumab or immune checkpoint inhibitors (ICI) to next-line platinum-pemetrexed chemotherapy was more common in Cohort 2 (bevacizumab use, 30.3 % vs 8.0 %, p = 0.002; ICI use, 33.0 % vs 2.0 %, p = 0.001). With a median duration of follow up of 30 months, there was a significant PFS benefit to continuing osimertinib with next line platinum pemetrexed chemotherapy (9.0 vs 4.5 months; HR 0.49, 95 % CI 0.32 - 0.74, p = 0.0032), also seen in subset analyses of patients who received first line osimertinib (n = 55, 11.0 vs 6.2 months; HR 0.41, 95 % CI 0.25 - 0.73, p = 0.002). Among patients with EGFR mutant NSCLC without brain metastases after progression on osimertinib, we found that continuing osimertinib with next line platinum pemetrexed significantly reduced the median time to CNS progression (n = 38; 7.0 vs 4.1 months; HR 0.47, 95 % CI 0.48 - 0.98, p = 0.01). After adjusted analysis, there was no significant OS difference between Cohorts 1 and 2 (19 months vs 13 months; HR 0.92, 95 % CI 0.60 - 1.39, p = 0.68).

CONCLUSIONS AND RELEVANCE

For patients with EGFR mutant NSCLC who progress on osimertinib, there is a significant PFS, but not OS, benefit to continuing osimertinib with next line platinum pemetrexed chemotherapy. The continuation of osimertinib with next line platinum pemetrexed chemotherapy appears to reduce the risk of CNS progression.

Study Protocol of the Korean EGFR Registry: A Multicenter Prospective and Retrospective Cohort Study in Nonsmall Cell Lung Cancer Patients With EGFR Mutation

INTRODUCTION

The provision of treatment for epidermal growth factor receptor (EGFR)-mutated nonsmall cell lung cancer (NSCLC) patients has increased in Korea. However, multicenter studies on the clinicopathologic dataset and treatment outcomes, using a large-scale dataset, have not been conducted. The current study is a prospective and retrospective multicenter observational cohort study that registers all stages of EGFR-mutated NSCLC patients.

METHODS

The Korean EGFR Registry was designed to enroll 2000 patients with all stages of EGFR-mutated NSCLC from 40 university hospitals across Korea. This study, encompassing both retrospective and prospective cohorts, aims to analyze clinical characteristics, treatment modalities, and outcomes in these patients. Data collection will include patient demographics, smoking history, quality of life assessments, pathological data, and treatment outcomes, with follow-up until December 2026. The primary endpoint is disease-free survival in patients who have undergone radical therapy (surgery and radiotherapy) or progression-free survival in those receiving targeted therapy (first, second, and subsequent lines), chemotherapy (first and subsequent lines), combination therapy, and palliative/maintenance therapy according to stages of EGFR-mutated NSCLC. The study will explore the diagnostic methods for EGFR mutations, clinical outcomes based on treatment modalities, and metastatic patterns in EGFR-mutated NSCLC patients. Moreover, it will investigate various aspects, including the safety and efficacy of a new third-generation EGFR tyrosine kinase inhibitor (TKI), lazertinib, approved for both first- and second-line treatments.

DISCUSSION

This study is expected to provide valuable insights into the epidemiology, risk factors, progression, and treatment outcomes of EGFR-mutated NSCLC in Korea. The Korean EGFR Registry will contribute significantly to the understanding of the complex dynamics of EGFR-mutated NSCLC, aiding in the development of more effective and personalized treatment strategies.

COMPOSIT study: evaluating osimertinib combination with targeted therapies in EGFR-mutated non-small cell lung cancer

INTRODUCTION

The emergence of diverse resistance mechanisms after osimertinib therapy, including on-target epidermal growth factor receptor (EGFR) mutations and off-target alterations, warrants investigation of novel therapeutics to overcome these challenges and improve patient outcomes.

METHODS

COMPOSIT was a French, retrospective, multicenter, cohort study of the effectiveness and tolerability of osimertinib in combination with other targeted therapies in patients with advanced EGFR-mutant (EGFRm) non-small cell lung cancer (NSCLC) who harbored other oncogenic drivers as primary or acquired resistance mechanisms. Real-world progression-free survival (rwPFS), overall survival (OS), and objective response rate (ORR) were the primary endpoints.

RESULTS

The study included 61 patients (63.9% women; median age, 61 years). Chemotherapy was administered to 26 patients (42.6%) before the combinations. The most frequently targeted resistance mechanisms were MET amplification (n = 40) and BRAF alterations (n = 11). Sixteen combinations of osimertinib with other targeted therapies were reported. Overall (except for 10 patients in clinical trials), median rwPFS and OS were 3.9 (95% CI, 2.9-5.2) and 9.8 months (95% CI, 6.8-14.8). Best ORR (n = 54) was 50% (95% CI, 33.0-72.8). In patients with MET amplification (n = 29), median rwPFS and OS were 4.9 (95% CI, 2.9-7.2) and 8.6 months (95% CI, 5.3-21.6). Grade ≥3 adverse events occurred in 15 patients (24.6%). No deaths were related to treatment.

CONCLUSIONS

Combinations of osimertinib with other targeted therapies appeared to be feasible and safe and may offer clinical benefit to overcome resistance to osimertinib in EGFRm NSCLC, especially in patients with MET amplification.

CXCR1+ neutrophil infiltration orchestrates response to third-generation EGFR-TKI in EGFR mutant non-small-cell lung cancer

Although third-generation Epidermal growth factor receptor-tyrosine kinase inhibitors (EGFR-TKI) is standard of care for patients with EGFR-mutant Non-small cell lung cancer (NSCLC), little is known about the predictors of response or resistance. Here, we integrated single-cell RNA (scRNA) sequencing, bulk RNA sequencing, multiplexed immunofluorescence and flow cytometry data from pretreatment and post-resistant tumor samples of EGFR-mutant NSCLC patients received third-generation EGFR-TKIs. We show that resistant samples had a markedly enriched CXCR1+ neutrophils infiltration (P < 0.01) than pretreatment samples, which were distinguished from other subtypes of neutrophils and displayed immunosupressive characteristics. Spatial analysis showed that increased CXCR1+ neutrophils predominantly infiltrated into the tumor core in resistant samples and the average distance of neutrophils to tumor cells markedly reduced from 33 to 19 μm. Deep analysis of scRNA and bulk RNA sequencing data revealed the increased interactions between CXCR1+ neutrophils and tumor cells and activated TNF-α/NF-κB signaling pathway in tumor cells of resistant samples. In vitro and in vivo experiments validated that CXCR1+ neutrophils resulted in resistance to third-generation EGFR-TKI via activating TNF-α/NF-κB signaling pathway in tumor cells. Importantly, patients with low pretreatment CXCR1+ neutrophil infiltration abundance had a dramatically longer progression-free survival (11.8 vs. 7.5 months; P = 0.019) and overall survival (33.0 vs. 23.5 months; P = 0.029) than those with high infiltration abundance. Collectively, these findings suggest that CXCR1+ neutrophils infiltration was associated with the efficacy of third-generation EGFR-TKI in patients with EGFR-mutant NSCLC.

Aberrant expression of MRAS and HEG1 as the biomarkers for osimertinib resistance in LUAD

Epidermal growth factor receptor (EGFR)-tyrosine kinase inhibitors (TKIs) are the most applied targeted therapy for EGFR-mutant lung adenocarcinoma (LUAD). The third-generation EGFR-TKI, osimertinib, is widely used throughout lung cancer treatment, with single or combination modes. One of the main barriers in osimertinib treatment is the acquired resistance and mechanisms are not fully understood. Gene expression other than genetic mutations might predict drug response and mediate resistance occurrence. We analyzed six datasets of osimertinib-resistant LUAD cells from the Gene Expression Omnibus (GEO) database and identified two hub genes, named MRAS and HEG1. We found that the expression mode of MRAS/HEG1 in LUAD was osimertinib-dependent and contributed to drug resistance. We also explored potential mechanisms of hub genes related osimertinib resistance and emphasized the M2 infiltration involved. Moreover, potential therapeutic agents conquering MRAS/HEG1-related resistance were also identified. In conclusion, MRAS and HEG1 might be responsible for osimertinib resistance and could be promising prognostic biomarkers for osimertinib response in LUAD, which might provide insights into therapeutic strategies.

ctDNA Dynamics and Mechanisms of Acquired Resistance in Patients Treated with Osimertinib with or without Bevacizumab from the Randomized Phase II ETOP-BOOSTER Trial

PURPOSE

The ETOP 10-16 BOOSTER study was a randomized phase II trial of osimertinib and bevacizumab therapy versus osimertinib therapy in patients with an acquired EGFR T790M mutation. The mechanisms of acquired resistance to osimertinib and bevacizumab have not been described previously.

EXPERIMENTAL DESIGN

Next-generation sequencing (Guardant360) was conducted in serial plasma samples. The association between ctDNA and efficacy outcomes was explored, and molecular alterations at progression were described.

RESULTS

A total of 136 patients (88% of 155 randomized) had plasma samples at baseline (68 per arm), 110 (71%) at week 9, and 65 (42%) at progression. In a multivariable model for progression-free survival (PFS), the treatment effect was found to differ by smoking status (interaction P = 0.046), with the effect of smoking also differing by baseline EGFR T790M (interaction P = 0.033), whereas both TP53 at baseline and the tissue EGFR exon 21 L858R mutation were significantly associated with worse PFS outcome. Smokers (current/former) without baseline EGFR T790M showed a significant improvement in PFS under combination treatment, albeit with small numbers (P = 0.015). Week-9 EGFR T790M clearance was associated with improved PFS in the osimertinib arm (P = 0.0097). Acquired EGFR C797S mutations were detected in 22% and 13% of patients in the combination and osimertinib arms, respectively.

CONCLUSIONS

The differential effect of treatment by smoking was not explained by TP53 mutations or other molecular alterations examined. Molecular mechanisms of acquired resistance were detected, but no novel molecular alterations were identified in the combination arm.

Inhibition of hTERT/telomerase/telomere mediates therapeutic efficacy of osimertinib in EGFR mutant lung cancer

The inevitable acquired resistance to osimertinib (AZD9291), an FDA-approved third-generation EGFR tyrosine kinase inhibitor (EGFR-TKI) for the treatment of patients with advanced non-small cell lung cancer (NSCLC) harboring EGFR activating or T790M resistant mutations, limits its long-term clinical benefit. Telomere maintenance via telomerase reactivation is linked to uncontrolled cell growth and is a cancer hallmark and an attractive cancer therapeutic target. Our effort toward understanding the action mechanisms, including resistance mechanisms, of osimertinib has led to the identification of a novel and critical role in maintaining c-Myc-dependent downregulation of hTERT, a catalytic subunit of telomerase, and subsequent inhibition of telomerase/telomere and induction of telomere dysfunction in mediating therapeutic efficacy of osimertinib. Consequently, osimertinib combined with the telomere inhibitor, 6-Thio-dG, which is currently tested in a phase II trial, effectively inhibited the growth of osimertinib-resistant tumors, regressed EGFRm NSCLC patient-derived xenografts, and delayed the emergence of acquired resistance to osimertinib, warranting clinical validation of this strategy to manage osimertinib acquired resistance.

Base editing screens define the genetic landscape of cancer drug resistance mechanisms

Drug resistance is a principal limitation to the long-term efficacy of cancer therapies. Cancer genome sequencing can retrospectively delineate the genetic basis of drug resistance, but this requires large numbers of post-treatment samples to nominate causal variants. Here we prospectively identify genetic mechanisms of resistance to ten oncology drugs from CRISPR base editing mutagenesis screens in four cancer cell lines using a guide RNA library predicted to install 32,476 variants in 11 cancer genes. We identify four functional classes of protein variants modulating drug sensitivity and use single-cell transcriptomics to reveal how these variants operate through distinct mechanisms, including eliciting a drug-addicted cell state. We identify variants that can be targeted with alternative inhibitors to overcome resistance and functionally validate an epidermal growth factor receptor (EGFR) variant that sensitizes lung cancer cells to EGFR inhibitors. Our variant-to-function map has implications for patient stratification, therapy combinations and drug scheduling in cancer treatment.

Longitudinal Analyses of Circulating Tumor DNA for the Detection of EGFR Mutation-Positive Advanced NSCLC Progression During Treatment: Data From FLAURA and AURA3

INTRODUCTION

EGFR tyrosine kinase inhibitor (EGFR-TKI)-sensitizing and -resistance mutations may be detected in plasma through circulating tumor DNA (ctDNA). Circulating tumor DNA level changes reflect alterations in tumor burden and could be a dynamic indicator of treatment effect. This analysis aimed to determine whether longitudinal EGFR-mutation ctDNA testing could detect progressive disease (PD) before radiologic detection.

METHODS

This was a retrospective, exploratory ctDNA analysis in two phase 3 trials (FLAURA, NCT02296125; AURA3, NCT02151981). Patients had treatment-naïve (FLAURA) or EGFR-TKI pre-treated (AURA3) advanced NSCLC with EGFR mutations and on-study PD (RECIST [Response Evaluation Criteria in Solid Tumors]), with a baseline ctDNA result and EGFR-mutation ctDNA monitoring beyond Cycle 3 Day 1. Patients received osimertinib versus comparator EGFR-TKIs (FLAURA) or chemotherapy (AURA3). Outcomes included time from ctDNA PD to RECIST PD and the first subsequent treatment (FLAURA only).

RESULTS

Circulating tumor DNA PD preceded or co-occurred with RECIST-defined PD in 93 out of 146 patients (64%) in FLAURA and 82 out of 146 patients (56%) in AURA3. Median time from ctDNA PD to RECIST-defined PD (mo) was 3.4 and 2.6 in the osimertinib and comparator EGFR-TKI arms (FLAURA) and 2.8 and 1.5 in the osimertinib and chemotherapy arms (AURA3). In FLAURA, the median time from ctDNA PD to the first subsequent treatment (mo) was 6.0 and 4.7 in the osimertinib (n = 51) and comparator EGFR-TKI arms (n = 70).

CONCLUSIONS

Among patients with EGFR mutation-positive advanced NSCLC receiving EGFR-TKI or chemotherapy with ctDNA data and RECIST-defined PD, ctDNA PD preceded/co-occurred with RECIST-defined PD in approximately 60% of cases. Longitudinal ctDNA monitoring may detect PD before radiologic PD.

METTL14-Mediated Bim mRNA m6A Modification Augments Osimertinib Sensitivity in EGFR-Mutant NSCLC Cells

Resistance to osimertinib represents a significant challenge for the successful treatment of non-small cell lung cancer (NSCLC) harboring activating mutations in EGFR. N6-methyladenosine (m6A) on mRNAs is critical for various biological processes, yet whether m6A regulates osimertinib resistance of NSCLC remains unknown. In this study, we demonstrated that developing osimertinib-resistant phenotypes depends on m6A reduction resulting from downexpression of m6A methyltransferase METTL14 in EGFR-mutant NSCLCs. Both in vitro and in vivo assays showed that specific knockdown of METTL14 was sufficient to confer osimertinib resistance and that elevated expression of METTL14 rescued the efficacy of osimertinib in the resistant NSCLC cells. Mechanistically, METTL14 promoted m6A methylation of pro-apoptotic Bim mRNA and increased Bim mRNA stability and expression, resulting in activating the Bim-dependent pro-apoptotic signaling and thereby promoting osimertinib-induced cell apoptosis. Analysis of clinical samples revealed that decreased expression of METTL14 was observed in osimertinib-resistant NSCLC tissues and significantly associated with a poor prognosis. In conclusion, our study reveals a novel regulatory mechanism by which METTL14-mediated m6A methylation of Bim mRNA inhibited osimertinib resistance of NSCLC cells. It offers more evidences for the involvement of m6A modification in regulation of osimertinib resistance and provides potential therapeutic targets for novel approaches to overcome the tolerance of osimertinib and other EGFR tyrosine kinase inhibitors. Implications: This study offers more evidences for the involvement of METTL14-mediated N6-methyladenosine modification in regulation of osimertinib resistance and provides potential therapeutic targets for novel approaches to overcome the tolerance of osimertinib and other EGFR tyrosine kinase inhibitors.