Tackling Osimertinib Resistance in EGFR-Mutant Non-Small Cell Lung Cancer

PPP3CB overexpression mediates EGFR TKI resistance in lung tumors via calcineurin/MEK/ERK signaling

Despite initial high response rates to first-line EGFR TKI, all non-small-cell lung cancer (NSCLC) with EGFR-activating mutation will ultimately develop resistance to treatment. Identification of resistance mechanisms is critical to adapt treatment and improve patient outcomes. Here, we show that a PPP3CB transcript that encodes full-length catalytic subunit 2B of calcineurin accumulates in EGFR-mutant NSCLC cells with acquired resistance against different EGFR TKIs and in post-progression biopsies of NSCLC patients treated with EGFR TKIs. Neutralization of PPP3CB by siRNA or inactivation of calcineurin by cyclosporin A induces apoptosis in resistant cells treated with EGFR TKIs. Mechanistically, EGFR TKIs increase the cytosolic level of calcium and trigger activation of a calcineurin/MEK/ERK pathway that prevents apoptosis. Combining EGFR, calcineurin, and MEK inhibitors overcomes resistance to EGFR TKI in both in vitro and in vivo models. Our results identify PPP3CB overexpression as a new mechanism of acquired resistance to EGFR TKIs, and provide a promising therapeutic approach for NSCLC patients that progress under TKI treatment.

Combined Therapeutic Strategies Based on the Inhibition of Non-Oncogene Addiction to Improve Tumor Response in EGFR- and KRAS-Mutant Non-Small-Cell Lung Cancer

BACKGROUND

Oncogene-driven NSCLC is usually treated with targeted therapies using tyrosine kinase inhibitors (TKIs) to inhibit oncogene downstream signaling pathways, affecting tumor survival and proliferation. EGFR- and KRAS-mutant NSCLCs are the most represented subtypes, and they are treated in clinical practice with oncogene-targeting drugs in the first and second line, respectively. Unfortunately, the development of oncogene-independent resistant clones limits TKI efficacy. Here, we used non-oncogene addiction (NOA) as an innovative therapeutic strategy to target other essential proteins that support changes in tumor phenotype. Specifically, we tested, for the first time, a combination of inhibitors, namely ATR, involved in DNA damage response, and pyruvate dehydrogenase kinases (PDKs), involved in energy metabolism.

METHODS

Sensitive PC9 and the corresponding EGFR-TKI-resistant PC9/OR, EGFR-mutant H1975, and KRAS-mutant A549 NSCLC cells, were treated with TKIs (osimertinib and selumetinib, respectively). In parallel, cells were exposed to two combination regimens: one using the TKI with an ATR inhibitor and the other one combining the two selected NOA inhibitors (ATR inhibitor, M4344; and PDK inhibitor, DCA).

RESULTS

The effect of these two combined approaches, compared to TKI alone, produced similar results in terms of cell proliferation, cell death, and migration. Thus, depending on tumor biology, selecting between the proposed therapeutic strategies will be different, to maximize tumor response.

CONCLUSIONS

The major translational relevance of this study is to exploit new targets for the development of innovative and improved therapeutic strategies with NOA drugs, over combinations including target genes within the oncogene pathway, to overcome resistance to TKI therapies in patients with NSCLC who are oncogene-addicted.

USP8-mediated PTK7 promotes PIK3CB-related pathway to accelerate the malignant progression of non-small cell lung cancer

BACKGROUND

Protein tyrosine kinase 7 (PTK7) has been found to be highly expressed in non-small cell lung cancer (NSCLC), but its specific molecular mechanism needs to be further explored.

METHODS

PTK7 mRNA expression in NSCLC tumor tissues was examined by quantitative real-time PCR. The protein levels of PTK7, ubiquitin-specific peptidase 8 (USP8), PIK3CB, and PI3K/AKT were determined by western blot. Human monocytes (THP-1) were induced into macrophages and then co-cultured with the conditioned medium of NSCLC cells. Macrophage M2 polarization was assessed by detecting CD206+ cells using flow cytometry. The interaction between PTK7 and USP8 or PIK3CB was assessed by Co-IP assay. Animal study was performed to evaluate the effects of PTK7 knockdown and PIK3CB on NSCLC tumorigenesis in vivo.

RESULTS

PTK7 expression was higher in NSCLC tumor tissues and cells. After silencing of PTK7, NSCLC cell proliferation, invasion, and macrophage M2 polarization were inhibited, while cell apoptosis was promoted. USP8 enhanced PTK7 protein expression by deubiquitination, and the repressing effects of USP8 knockdown on NSCLC cell growth, invasion, and macrophage M2 polarization were reversed by PTK7 overexpression. PTK7 interacted with PIK3CB, and PIK3CB overexpression could abolish the regulation of PTK7 silencing on NSCLC cell progression. USP8 positively regulated PIK3CB expression by PTK7, thus activating PI3K/AKT pathway. Downregulation of PTK7 reduced NSCLC tumorigenesis by decreasing PIK3CB expression.

CONCLUSION

USP8-deubiquitinated PTK7 facilitated NSCLC malignant behavior via activating the PIK3CB/PI3K/AKT pathway, providing new idea for NSCLC treatment.

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.

Xanthohumol overcomes osimertinib resistance via governing ubiquitination-modulated Ets-1 turnover

Non-small cell lung cancer (NSCLC) is a prevalent and fatal malignancy with a significant global impact. Recent advancements have introduced targeted therapies like tyrosine kinase inhibitors (TKIs) such as osimertinib, which have improved patient outcomes, particularly in those with EGFR mutations. Despite these advancements, acquired resistance to TKIs remains a significant challenge. Hence, one of the current research priorities is understanding the resistance mechanisms and identifying new therapeutic targets to improve therapeutic efficacy. Herein, we identified high expression of c-Met in osimertinib-resistant NSCLC cells, and depletion of c-Met significantly inhibited the proliferation of osimertinib-resistant cells and prolonged survival in mice, suggesting c-Met as an attractive therapeutic target. To identify effective anti-tumor agents targeting c-Met, we screened a compound library containing 641 natural products and found that only xanthohumol exhibited potent inhibitory effects against osimertinib-resistant NSCLC cells. Moreover, combination treatment with xanthohumol and osimertinib sensitized osimertinib-resistant NSCLC cells to osimertinib both in vitro and in vivo. Mechanistically, xanthohumol disrupted the interaction between USP9X and Ets-1, and inhibited the phosphorylation of Ets-1 at Thr38, promoting its degradation, thereby targeting the Ets-1/c-Met signaling axis and inducing intrinsic apoptosis in osimertinib-resistant NSCLC cells. Overall, the research highlights the critical role of targeting c-Met to address osimertinib resistance in NSCLC. By demonstrating the efficacy of xanthohumol in overcoming resistance and enhancing therapeutic outcomes, this study provides valuable insights and potential new strategies for improving the clinical management of NSCLC.

Comprehensive liquid biopsy analysis for monitoring NSCLC patients under second-line osimertinib treatment

Background

The heterogeneous and complex genetic landscape of NSCLC impacts the clinical outcomes of patients who will eventually develop resistance to osimertinib. Liquid biopsy (LB) analysis as a minimally invasive approach is a key step to efficiently identify resistance mechanisms and adjust to proper subsequent treatments.

Materials and methods

In the present study, we combined plasma-cfDNA and CTC analysis from 30 NSCLC patients in samples collected before treatment and at the progression of disease (PD). We detected molecular alterations at the DNA mutation (EGFR, PIK3CA, KRAS G12C, BRAF V600E), DNA methylation (RASSF1A, BRMS1, FOXA1, SLFN1, SHISA3, RARβ,, WIF-1, RASSF10 and APC), gene expression (CK-19, CK-18, CK-8, AXL, TWIST-1, PD-L1, PIM-1, Vimentin, ALDH-1, and B2M) and chromosomal level (HER2 and MET amplification) as possible resistance mechanisms and druggable targets. We also studied the expression of PD-L1 in single CTCs using immunofluorescence.

Results

In some cases, T790M resistance EGFR mutation was detected at baseline in CTCs but not in the corresponding plasma cfDNA. PIK3CA mutations were detected only in plasma-cfDNA but not in corresponding CTCs. KRAS G12C and BRAF V600E mutations were not detected in the samples analyzed. MET amplification was detected in the CTCs of two patients before treatment whereas HER2 amplification was detected in the CTCs of three patients at baseline and in one patient at PD. DNA methylation analysis revealed low concordance between CTCs and cfDNA, indicating the complementary information obtained through parallel LB analysis. Results from gene expression analysis indicated high rates of vimentin-positive CTCs detected at all time points during osimertinib. Moreover, there was an increased number of NSCLC patients at PD harboring CTCs positive in PD-L1. AXL and PIM-1 expression detected in CTCs during treatment suggesting new possible therapeutic strategies.

Discussion

Our results reveal that comprehensive liquid biopsy analysis can efficiently represent the heterogeneous molecular landscape and provide prominent information on subsequent treatments for NSCLC patients at PD since druggable molecular alterations were detected in CTCs.

Targeting focal adhesion kinase (FAK) in cancer therapy: A recent update on inhibitors and PROTAC degraders

Focal adhesion kinase (FAK) is considered as a pivotal intracellular non-receptor tyrosine kinase, and has garnered significant attention as a promising target for anticancer drug development. As of early 2024, a total of 12 drugs targeting FAK have been approved for clinical or preclinical studies worldwide, including three PROTAC degraders. In recent three years (2021-2023), significant progress has been made in designing targeted FAK anticancer agents, including the development of a novel benzenesulfofurazan type NO-releasing FAK inhibitor and the first-in-class dual-target inhibitors simultaneously targeting FAK and HDACs. Given the pivotal role of FAK in the discovery of anticancer drugs, as well as the notable advancements achieved in FAK inhibitors and PROTAC degraders in recent years, this review is underbaked to present a comprehensive overview of the function and structure of FAK. Additionally, the latest findings on the inhibitors and PROTAC degraders of FAK from the past three years, along with their optimization strategies and anticancer activities, were summarized, which might help to provide novel insights for the development of novel targeted FAK agents with promising anticancer potential and favorable pharmacological profiles.

Initial AXL and MCL-1 inhibition contributes to abolishing lazertinib tolerance in EGFR-mutant lung cancer cells

Lazertinib, a novel third-generation epidermal growth factor receptor tyrosine kinase inhibitor (EGFR-TKI), demonstrates marked efficacy in EGFR-mutant lung cancer. However, resistance commonly develops, prompting consideration of therapeutic strategies to overcome initial drug resistance mechanisms. This study aimed to elucidate the adaptive resistance to lazertinib and advocate novel combination treatments that demonstrate efficacy in preventing resistance as a first-line treatment for EGFR mutation-positive NSCLC. We found that AXL knockdown significantly inhibited lung cancer cell viability in the presence of lazertinib, indicating that AXL activation contributes to lazertinib resistance. However, long-term culture with a combination of lazertinib and AXL inhibitors led to residual cell proliferation and increased the MCL-1 expression level, which was mediated by the nuclear translocation of the transcription factor YAP. Triple therapy with an MCL-1 or YAP inhibitor in combination with lazertinib and an AXL inhibitor significantly reduced cell viability and increased the apoptosis rate. These results demonstrate that AXL and YAP/MCL-1 signals contribute to adaptive lazertinib resistance in EGFR-mutant lung cancer cells, suggesting that the initial dual inhibition of AXL and YAP/MCL-1 might be a highly effective strategy in eliminating lazertinib-resistant cells.

Targeting metabolic adaptive responses induced by glucose starvation inhibits cell proliferation and enhances cell death in osimertinib-resistant non-small cell lung cancer (NSCLC) cell lines

Osimertinib, a tyrosine kinase inhibitor targeting mutant EGFR, has received approval for initial treatment in patients with Non-Small Cell Lung Cancer (NSCLC). While effective in both first- and second-line treatments, patients eventually develop acquired resistance. Metabolic reprogramming represents a strategy through which cancer cells may resist and adapt to the selective pressure exerted by the drug. In the current study, we investigated the metabolic adaptations associated with osimertinib-resistance in NSCLC cells under low glucose culture conditions. We demonstrated that, unlike osimertinib-sensitive cells, osimertinib-resistant cells were able to survive under low glucose conditions by increasing the rate of glucose and glutamine uptake and by shifting towards mitochondrial metabolism. Inhibiting glucose/pyruvate contribution to mitochondrial respiration, glutamine deamination to glutamate, and oxidative phosphorylation decreased the proliferation and survival abilities of osimertinib-resistant cells to glucose starvation. Our findings underscore the remarkable adaptability of osimertinib-resistant NSCLC cells in a low glucose environment and highlight the pivotal role of mitochondrial metabolism in mediating this adaptation. Targeting the metabolic adaptive responses triggered by glucose shortage emerges as a promising strategy, effectively inhibiting cell proliferation and promoting cell death in osimertinib-resistant cells.

Non-small-cell lung cancer

Non-small-cell lung cancer (NSCLC) is one of the most frequent cancer types and is responsible for the majority of cancer-related deaths worldwide. The management of NSCLC has improved considerably, especially in the past 10 years. The systematic screening of populations at risk with low-dose CT, the implementation of novel surgical and radiotherapeutic techniques and a deeper biological understanding of NSCLC that has led to innovative systemic treatment options have improved the prognosis of patients with NSCLC. In non-metastatic NSCLC, the combination of various perioperative strategies and adjuvant immunotherapy in locally advanced disease seem to enhance cure rates. In metastatic NSCLC, the implementation of novel drugs might prolong disease control together with preserving quality of life. The further development of predictive clinical and genetic markers will be essential for the next steps in individualized treatment concepts.

Anlotinib reverses osimertinib resistance via inhibiting epithelial-to-mesenchymal transition and angiogenesis in non-small cell lung cancer

In the present, we aimed to investigate the effect of anlotinib on the potential reversal of osimertinib resistance by inhibiting the formation of epithelial-to-mesenchymal transition (EMT) and angiogenesis. In a clinical case, anlotinib reversed osimertinib resistance in Non-small cell lung cancer (NSCLC). We performed an immunohistochemical experiment on tumor tissues from three non-small cell lung cancer patients exhibiting osimertinib resistance to analyze alterations in the expression levels of EMT markers and vascular endothelial growth factor A (VEGFA) before and after osimertinib resistance. The results revealed the downregulation of E-cadherin, coupled with the upregulation of vimentin and VEGFA in tumor tissues of patients exhibiting osimertinib resistance, compared with the expression in tissues of patients before taking osimertinib. Subsequently, we established osimertinib-resistant cell lines and found that the osimertinib-resistant cells acquired the EMT features. Then, we analyzed the synergistic effects of the combination therapy to verify whether anlotinib could reverse osimertinib resistance by inhibiting EMT. The expression levels of VEGFA and micro-vessels were analyzed in the combination group in vitro. Finally, we explored the reversal of osimertinib resistance in combination with anlotinib in vivo with 20 nude mice. The combined treatment of osimertinib and anlotinib effectively prevented the metastasis of resistant cells, which also inhibited tumor growth, exerted anti-tumor activity, and ultimately reversed osimertinib resistance in mice. The co-administration of osimertinib and anlotinib demonstrated their synergistic efficacy in inhibiting EMT and angiogenesis in three NSCLC patients, ultimately reversing osimertinib resistance.

Companion Tests and Personalized Cancer Therapy: Reaching a Glass Ceiling

The use of companion diagnostics has become a standard in precision oncology in the context of ongoing therapeutic innovation. However, certain limitations make their application imperfect in current practice. This position paper underscores the need to broaden the notion of companion testing, considering the potential of emerging technologies, including computational biology, to overcome these limitations. This wave of progress should impact not only our representation of the analytical tool itself but also the nature of the tumoral sample under analysis (liquid biopsies). The complex inter-relationship between companion test guided-personalized therapy, and health agency policies for new drug agreements will also be discussed.

Radiogenomics: bridging the gap between imaging and genomics for precision oncology

Genomics allows the tracing of origin and evolution of cancer at molecular scale and underpin modern cancer diagnosis and treatment systems. Yet, molecular biomarker-guided clinical decision-making encounters major challenges in the realm of individualized medicine, consisting of the invasiveness of procedures and the sampling errors due to high tumor heterogeneity. By contrast, medical imaging enables noninvasive and global characterization of tumors at a low cost. In recent years, radiomics has overcomes the limitations of human visual evaluation by high-throughput quantitative analysis, enabling the comprehensive utilization of the vast amount of information underlying radiological images. The cross-scale integration of radiomics and genomics (hereafter radiogenomics) has the enormous potential to enhance cancer decoding and act as a catalyst for digital precision medicine. Herein, we provide a comprehensive overview of the current framework and potential clinical applications of radiogenomics in patient care. We also highlight recent research advances to illustrate how radiogenomics can address common clinical problems in solid tumors such as breast cancer, lung cancer, and glioma. Finally, we analyze existing literature to outline challenges and propose solutions, while also identifying future research pathways. We believe that the perspectives shared in this survey will provide a valuable guide for researchers in the realm of radiogenomics aiming to advance precision oncology.

Downregulation of Rad51 Expression and Activity Potentiates the Cytotoxic Effect of Osimertinib in Human Non-Small Cell Lung Cancer Cells

INTRODUCTION

Osimertinib (AZD9291) is a third-generation epidermal growth factor receptor (EGFR) tyrosine kinase inhibitor that has shown significant clinical benefits in patients with EGFR-sensitizing mutations or the EGFR T790M mutation. The homologous recombination (HR) pathway is crucial for repairing DNA double-strand breaks (DSBs). Rad51 plays a central role in HR, facilitating the search for homology and promoting DNA strand exchange between homologous DNA molecules. Rad51 is overexpressed in numerous types of cancer cells. B02, a specific small molecule inhibitor of Rad51, inhibits the DNA strand exchange activity of Rad51. Previous studies have indicated that B02 disrupted Rad51 foci formation in response to DNA damage and inhibited DSBs repair in human cells and sensitized them to chemotherapeutic drugs in vitro and in vivo. However, the potential therapeutic effects of combining osimertinib with a Rad51 inhibitor are not well understood. The aim of this study was to elucidate whether the downregulation of Rad51 expression and activity can enhance the osimertinib-induced cytotoxicity in non-small cell lung cancer (NSCLC) cells.

METHODS

We used the MTS, trypan blue dye exclusion and colony-formation ability assay to determine whether osimertinib alone or in combination with B02 had cytotoxic effects on NSCLC cell lines. Real-time polymerase chain reaction was conducted to measure the amounts of Rad51 mRNA. The protein levels of phosphorylated AKT and Rad51 were determined by Western blot analysis.

RESULTS

We found that osimertinib reduced Rad51 expression by inactivating AKT activity. Rad51 knockdown using small interfering RNA or AKT inactivation through the phosphatidylinositol 3-kinase inhibitor LY294002 or si-AKT RNA transfection enhanced the cytotoxic and growth inhibitory effects of osimertinib. In contrast, AKT-CA (a constitutively active form of AKT) vector-enforced expression could mitigate the cytotoxic and cell growth inhibitory effects of osimertinib. Furthermore, B02 significantly enhanced the cytotoxic and cell growth inhibitory effects of osimertinib in NSCLC cells. Compared to parental cells, the activation of AKT and Rad51 expression in osimertinib-resistant cells could not be significantly inhibited by osimertinib treatment. Moreover, the increased expression of Rad51 is associated with the resistance mechanism in osimertinib-resistant H1975 and A549 cells.

CONCLUSION

Collectively, the downregulation of Rad51 expression and activity enhances the cytotoxic effect of osimertinib in human NSCLC cells.

Neoadjuvant sintilimab plus chemotherapy in EGFR-mutant NSCLC: Phase 2 trial interim results (NEOTIDE/CTONG2104)

The clinical efficacy of neoadjuvant immunotherapy plus chemotherapy remains elusive in localized epidermal growth factor receptor (EGFR)-mutant non-small cell lung cancer (NSCLC). Here, we report interim results of a Simon's two-stage design, phase 2 trial using neoadjuvant sintilimab with carboplatin and nab-paclitaxel in resectable EGFR-mutant NSCLC. All 18 patients undergo radical surgery, with one patient experiencing surgery delay. Fourteen patients exhibit confirmed radiological response, with 44% achieving major pathological response (MPR) and no pathological complete response (pCR). Similar genomic alterations are observed before and after treatment without influencing the efficacy of subsequent EGFR-tyrosine kinase inhibitors (TKIs) in vitro. Infiltration and T cell receptor (TCR) clonal expansion of CCR8+ regulatory T (Treg)hi/CXCL13+ exhausted T (Tex)lo cells define a subtype of EGFR-mutant NSCLC highly resistant to immunotherapy, with the phenotype potentially serving as a promising signature to predict immunotherapy efficacy. Informed circulating tumor DNA (ctDNA) detection in EGFR-mutant NSCLC could help identify patients nonresponsive to neoadjuvant immunochemotherapy. These findings provide supportive data for the utilization of neoadjuvant immunochemotherapy and insight into immune resistance in EGFR-mutant NSCLC.

Kinase Inhibitors and Kinase-Targeted Cancer Therapies: Recent Advances and Future Perspectives

Over 120 small-molecule kinase inhibitors (SMKIs) have been approved worldwide for treating various diseases, with nearly 70 FDA approvals specifically for cancer treatment, focusing on targets like the epidermal growth factor receptor (EGFR) family. Kinase-targeted strategies encompass monoclonal antibodies and their derivatives, such as nanobodies and peptides, along with innovative approaches like the use of kinase degraders and protein kinase interaction inhibitors, which have recently demonstrated clinical progress and potential in overcoming resistance. Nevertheless, kinase-targeted strategies encounter significant hurdles, including drug resistance, which greatly impacts the clinical benefits for cancer patients, as well as concerning toxicity when combined with immunotherapy, which restricts the full utilization of current treatment modalities. Despite these challenges, the development of kinase inhibitors remains highly promising. The extensively studied tyrosine kinase family has 70% of its targets in various stages of development, while 30% of the kinase family remains inadequately explored. Computational technologies play a vital role in accelerating the development of novel kinase inhibitors and repurposing existing drugs. Recent FDA-approved SMKIs underscore the importance of blood-brain barrier permeability for long-term patient benefits. This review provides a comprehensive summary of recent FDA-approved SMKIs based on their mechanisms of action and targets. We summarize the latest developments in potential new targets and explore emerging kinase inhibition strategies from a clinical perspective. Lastly, we outline current obstacles and future prospects in kinase inhibition.

DNA topoisomerase II inhibition potentiates osimertinib's therapeutic efficacy in EGFR-mutant non-small cell lung cancer models

Development of effective strategies to manage the inevitable acquired resistance to osimertinib, a third-generation EGFR inhibitor for the treatment of EGFR-mutant (EGFRm) non-small cell lung cancer (NSCLC), is urgently needed. This study reports that DNA topoisomerase II (Topo II) inhibitors, doxorubicin and etoposide, synergistically decreased cell survival, with enhanced induction of DNA damage and apoptosis in osimertinib-resistant cells; suppressed the growth of osimertinib-resistant tumors; and delayed the emergence of osimertinib-acquired resistance. Mechanistically, osimertinib decreased Topo IIα levels in EGFRm NSCLC cells by facilitating FBXW7-mediated proteasomal degradation, resulting in induction of DNA damage; these effects were lost in osimertinib-resistant cell lines that possess elevated levels of Topo IIα. Increased Topo IIα levels were also detected in the majority of tissue samples from patients with NSCLC after relapse from EGFR tyrosine kinase inhibitor treatment. Enforced expression of an ectopic TOP2A gene in sensitive EGFRm NSCLC cells conferred resistance to osimertinib, whereas knockdown of TOP2A in osimertinib-resistant cell lines restored their susceptibility to osimertinib-induced DNA damage and apoptosis. Together, these results reveal an essential role of Topo IIα inhibition in mediating the therapeutic efficacy of osimertinib against EGFRm NSCLC, providing scientific rationale for targeting Topo II to manage acquired resistance to osimertinib.

Perioperative Treatment Strategies in EGFR-Mutant Early-Stage NSCLC: Current Evidence and Future Challenges

Treatment with 3 years of adjuvant osimertinib is considered a new standard in patients with completely resected stage I to IIIA NSCLC harboring a common sensitizing EGFR mutation. This therapeutic approach significantly prolonged the disease-free survival and the overall survival versus placebo and revealed a significant role in preventing the occurrence of brain metastases. However, many unanswered questions remain, including the optimal duration of this therapy, whether all patients benefit from adjuvant osimertinib, and the role of adjuvant chemotherapy in this population. Indeed, there is a renewed interest in neoadjuvant strategies with targeted therapies in resectable NSCLC harboring oncogenic drivers. In light of these considerations, we discuss the past and current treatment options, and the clinical challenges that should be addressed to optimize the treatment outcomes in this patient population.