Positive Non-small Cell Lung Cancer Research Articles

Targeting ErbB and tankyrase1/2 prevent the emergence of drug-tolerant persister cells in ALK-positive lung cancer

AbstractTargeting the drug tolerant persister (DTP) state in cancer cells should prevent further development of resistance mechanisms. This study explored combination therapies to inhibit alectinib-induced DTP cell formation from anaplastic lymphoma kinase–positive non-small cell lung cancer (ALK + NSCLC) patient–derived cells. After drug-screening 3114 compounds, pan-HER inhibitors (ErbB pathway) and tankyrase1/2 inhibitors (Wnt/β-catenin signaling) emerged as top candidates to inhibit alectinib-induced DTP cells growth. We confirmed knockdown of both TNKS1/2 in DTP cells recovered the sensitivity to alectinib. Further, our study suggested knockdown of TNKS1/2 increased stability of Axin1/2, which induced β-catenin degradation and decreased its nuclear translocation, thereby suppressing transcription of antiapoptotic and proliferation-related genes (survivin, c-MYC). Targeting both pathways with alectinib+pan-HER inhibitor and alectinib+TNKS1/2 inhibitor suppressed alectinib-induced DTP cells, and the triple combination almost completely prevented the appearance of DTP cells. In conclusion, combination with ALK-TKI, pan-HER and TNKS1/2 inhibitors has the potential to prevent the emergence of DTP in ALK + NSCLC.

Successful Treatment With Lorlatinib Monotherapy for Secondary Central Nervous System Oligometastatic Disease in Refractory Anaplastic Lymphoma Kinase Positive Non-small Cell Lung Cancer

Successful Treatment With Lorlatinib Monotherapy for Secondary Central Nervous System Oligometastatic Disease in Refractory Anaplastic Lymphoma Kinase Positive Non-small Cell Lung Cancer

EP.12A.04 Patterns of Osimertinib Dose-Reduction and Impact on Outcomes in EGFR-Mutation Positive Non-Small Cell Lung Cancer

EP.12A.04 Patterns of Osimertinib Dose-Reduction and Impact on Outcomes in EGFR-Mutation Positive Non-Small Cell Lung Cancer

Highly sensitive and accurate detection of ALK-TKI resistance mutations by oligoribonucleotide interference-PCR (ORNi-PCR)-based methods

BackgroundPatients with anaplastic lymphoma kinase (ALK)-positive non-small cell lung cancer (NSCLC) are treated with ALK tyrosine kinase inhibitors (TKIs). Although most patients benefit from ALK-TKIs, the development of resistance mutations is common and results in NSCLC recurrence. To identify ALK-TKI-resistant NSCLC at the early recurrent phase, highly sensitive and accurate methods for the detection of mutations are essential. ObjectiveThe aim of this study was to establish highly sensitive, accurate, cost-effective, and clinically practical methods for the detection of two frequent ALK-TKI resistance mutations, ALK G1202R and L1196M, by liquid biopsy. MethodsThe efficacy of oligoribonucleotide interference-PCR (ORNi-PCR) was examined by first optimizing experimental conditions to specifically amplify the ALK-TKI resistance mutant DNA corresponding to ALK G1202R and L1196M mutations. ORNi-PCR was then combined with droplet digital PCR (ddPCR) or real-time PCR to detect these mutations in cell-free DNA (cfDNA) extracted from NSCLC patients. ResultsORNi-PCR followed by ddPCR/real-time PCR detected 1–10 copy(s) of G1202R and L1196M DNA in model cfDNA. These mutations in patients’ cfDNA were identified using ORNi-PCR-based methods, whereas conventional ddPCR failed to detect them. ConclusionORNi-PCR followed by ddPCR/real-time PCR enables highly sensitive and accurate detection of ALK mutations by liquid biopsy. Although the clinical data are limited, our results show that these methods are potentially useful for identifying ALK-TKI-resistant NSCLC at the early recurrent phase.

Beyond KRAS(G12C): Biochemical and Computational Characterization of Sotorasib and Adagrasib Binding Specificity and the Critical Role of H95 and Y96.

Mutated KRAS proteins are frequently expressed in some of the most lethal human cancers and thus have been a target of intensive drug discovery efforts for decades. Lately, KRAS(G12C) switch-II pocket (SII-P)-targeting covalent small molecule inhibitors have finally reached clinical practice. Sotorasib (AMG-510) was the first FDA-approved covalent inhibitor to treat KRAS(G12C)-positive nonsmall cell lung cancer (NSCLC), followed soon by adagrasib (MRTX849). Both drugs target the GDP-bound state of KRAS(G12C), exploiting the strong nucleophilicity of acquired cysteine. Here, we evaluate the similarities and differences between sotorasib and adagrasib in their RAS SII-P binding by applying biochemical, cellular, and computational methods. Exact knowledge of SII-P engagement can enable targeting this site by reversible inhibitors for KRAS mutants beyond G12C. We show that adagrasib is strictly KRAS- but not KRAS(G12C)-specific due to its strong and unreplaceable interaction with H95. Unlike adagrasib, sotorasib is less dependent on H95 for its binding, making it a RAS isoform-agnostic compound, having a similar functionality also with NRAS and HRAS G12C mutants. Our results emphasize the accessibility of SII-P beyond oncogenic G12C and aid in understanding the molecular mechanism behind the clinically observed drug resistance, associated especially with secondary mutations on KRAS H95 and Y96.

Inhibiting the Otub1/phosphorylated STAT3 axis for the treatment of non-small cell lung cancer.

The transcription factor STAT3 is a promising target for the treatment of non-small cell lung cancer (NSCLC). STAT3 activity is mainly dependent on phosphorylation at tyrosine 705 (pSTAT3-Y705), but the modulation on pSTAT3-Y705 is elusive. By screening a library of deubiquitinases (Dubs), we found that the Otub1 increasesSTAT3 transcriptional activity. As a Dub, Otub1 binds to pSTAT3-Y705 and specifically abolishes its K48-linked ubiquitination, therefore preventing its degradation and promoting NSCLC cell survival. The Otub1/pSTAT3-Y705 axis could be a potential target for the treatment of NSCLC. To explore this concept, we screen libraries of FDA-approved drugs and natural products based on STAT3-recognition element-driven luciferase assay, from which crizotinib is found to block pSTAT3-Y705 deubiquitination and promotes its degradation. Different from its known action to induce ALK positive NSCLC cell apoptosis, crizotinib suppresses ALK-intact NSCLC cell proliferation and colony formation but not apoptosis. Furthermore, crizotinib also suppresses NSCLC xenograft growth in mice. Taken together, these findings identify Otub1 as the first deubiquitinase of pSTAT3-Y705 and provide that the Otub1/pSTAT3-Y705 axis is a promising target for the treatment of NSCLC.

FDA Approval Summary: Repotrectinib for Locally Advanced or Metastatic ROS1-Positive Non-Small Cell Lung Cancer.

On November 15, 2023, the U.S. Food and Drug Administration (FDA) granted traditional approval to repotrectinib (Augtyro, Bristol Myers Squibb Corporation) for the treatment of adult patients with locally advanced or metastatic receptor tyrosine kinase encoded by the ROS1 gene (ROS1)-positive non-small cell lung cancer (NSCLC). The approval was based on TRIDENT-1, a single-arm trial with multiple cohorts of patients with ROS1 fusion-positive (hereafter "ROS1-positive") NSCLC (NCT03093116), who were either treatment naïve or had received prior ROS1 tyrosine kinase inhibitor (TKI) and/or platinum-based chemotherapy. The primary efficacy outcome measure is objective response rate (ORR) assessed by blinded independent central review (BICR) using response evaluation criteria in solid tumors version 1.1. ORR was assessed in 71 patients who were ROS1 TKI naïve and 56 patients who had received a prior ROS1 TKI. Among the 71 patients who were ROS1 TKI naïve, the ORR was 79% (95% CI, 68-88), median duration of response was 34.1 months (95% CI, 26-NE). In patients who had received a prior ROS1 TKI and no prior chemotherapy, the ORR was 38% (95% CI, 25-52). The median duration of response was 14.8 months (95% CI, 7.6-NE); BICR-assessed responses were observed in CNS metastases in patients in both cohorts and in patients who developed resistance mutations following prior TKI therapy. The most common (>20%) adverse reactions were dizziness, dysgeusia, peripheral neuropathy, constipation, dyspnea, ataxia, fatigue, cognitive disorders, and muscular weakness. A unique feature of this ROS1 TKI approval is the inclusion of robust evidence of efficacy in patients with ROS1-positive NSCLC who had progressed on prior ROS1 TKIs.

Redefining Recovery: The Transformative Impact of the ALINA Trial on Adjuvant Therapy for ALK-Positive Non-Small Cell Lung Cancer.

On April 18, 2024, the Food and Drug Administration approved alectinib as an adjuvant treatment for patients with anaplastic lymphoma kinase (ALK)-positive non-small cell lung cancer (NSCLC) after tumor resection. This approval was grounded in the outcomes of the ALINA trial, which demonstrated that alectinib significantly enhances disease-free survival compared to traditional platinum-based chemotherapy in the adjuvant setting. The ALINA trial is notable not just for advancing ALK tyrosine kinase inhibitors (TKIs) into the adjuvant setting but also for its innovative approach of comparing them to adjuvant chemotherapy, distinguishing it from other landmark trials.

Chinese Expert Consensus on the Standardized Diagnosis and Treatment of Non‑small Cell Lung Cancer with EGFR Exon 20 Insertion Mutations (2024 Edition)

The standard clinical practice of managing the non-small cell lung cancer (NSCLC) with epidermal growth factor receptor (EGFR) exon 20 insertion (ex20ins) mutations was elaborated in Chinese expert consensus on non‑small cell lung cancer with EGFR exon 20 insertion mutations (2023 edition), and this rare subset has gradually attracted attention recently. With the deepening of treatment area exploration and the approval of new targeted drugs, there are more options for the diagnosis and treatment of EGFR ex20ins positive NSCLC patients. Therefore, based on the previous version of consensus, the expert panel has updated this consensus on the standardized clinical diagnosis and treatment of EGFR ex20ins mutation NSCLC through reference to literature and clinical data, and combined with the experts' own clinical experience. The updated recommendations includes disease congnition, testing methods, therapy and recent relevant clinical trials for NSCLC patients with EGFR ex20ins mutation, in order to provide better medication reference for clinical physicians. .

IC Regimen: Delaying Resistance to Lorlatinib in ALK Driven Cancers by Adding Repurposed Itraconazole and Cilostazol.

Lorlatinib is a pharmaceutical ALK kinase inhibitor used to treat ALK driven non-small cell lung cancers. This paper analyses the intersection of past published data on the physiological consequences of two unrelated drugs from general medical practice-itraconazole and cilostazol-with the pathophysiology of ALK positive non-small cell lung cancer. A conclusion from that data analysis is that adding itraconazole and cilostazol may make lorlatinib more effective. Itraconazole, although marketed worldwide as a generic antifungal drug, also inhibits Hedgehog signaling, Wnt signaling, hepatic CYP3A4, and the p-gp efflux pump. Cilostazol, marketed worldwide as a generic thrombosis preventative drug, acts by inhibiting phosphodiesterase 3, and, by so doing, lowers platelets' adhesion, thereby partially depriving malignant cells of the many tumor trophic growth factors supplied by platelets. Itraconazole may enhance lorlatinib effectiveness by (i) reducing or stopping a Hedgehog-ALK amplifying feedback loop, by (ii) increasing lorlatinib's brain levels by p-gp inhibition, and by (iii) inhibiting growth drive from Wnt signaling. Cilostazol, surprisingly, carries minimal bleeding risk, lower than that of aspirin. Risk/benefit assessment of the combination of metastatic ALK positive lung cancer being a low-survival disease with the predicted safety of itraconazole-cilostazol augmentation of lorlatinib favors a trial of this drug trio in ALK positive lung cancer.

Clinical and molecular significance of homologous recombination deficiency positive non-small cell lung cancer in Chinese population: An integrated genomic and transcriptional analysis.

The clinical significance of homologous recombination deficiency (HRD) in breast cancer, ovarian cancer, and prostate cancer has been established, but the value of HRD in non-small cell lung cancer (NSCLC) has not been fully investigated. This study aimed to systematically analyze the HRD status of untreated NSCLC and its relationship with patient prognosis to further guide clinical care. A total of 355 treatment-naïve NSCLC patients were retrospectively enrolled. HRD status was assessed using the AmoyDx Genomic Scar Score (GSS), with a score of ≥50 considered HRD-positive. Genomic, transcriptomic, tumor microenvironmental characteristics and prognosis between HRD-positive and HRD-negative patients were analyzed. Of the patients, 25.1% (89/355) were HRD-positive. Compared to HRD-negative patients, HRD-positive patients had more somatic pathogenic homologous recombination repair (HRR) mutations, higher tumor mutation burden (TMB) (P<0.001), and fewer driver gene mutations (P<0.001). Furthermore, HRD-positive NSCLC had more amplifications in PI3K pathway and cell cycle genes, MET and MYC in epidermal growth factor receptor (EGFR)/anaplastic lymphoma kinase (ALK) mutant NSCLC, and more PIK3CA and AURKA in EGFR/ALK wild-type NSCLC. HRD-positive NSCLC displayed higher tumor proliferation and immunosuppression activity. HRD-negative NSCLC showed activated signatures of major histocompatibility complex (MHC)-II, interferon (IFN)-γ and effector memory CD8+ T cells. HRD-positive patients had a worse prognosis and shorter progression-free survival (PFS) to targeted therapy (first- and third-generation EGFR-TKIs) (P=0.042). Additionally, HRD-positive, EGFR/ALK wild-type patients showed a numerically lower response to platinum-free immunotherapy regimens. Unique genomic and transcriptional characteristics were found in HRD-positive NSCLC. Poor prognosis and poor response to EGFR-TKIs and immunotherapy were observed in HRD-positive NSCLC. This study highlights potential actionable alterations in HRD-positive NSCLC, suggesting possible combinational therapeutic strategies for these patients.

Post-marketing safety of lorlatinib: a real-world study based on the FDA adverse event reporting system.

Lorlatinib displays marked systemic and intracranial efficacy against anaplastic lymphoma kinase (ALK) positive non-small cell lung cancer (NSCLC). We aimed to establish the safety profile of lorlatinib based on the Food and Drug Administration Adverse Event Reporting System (FAERS). Reports from the FAERS between 2019 and 2023 were collected to conduct the disproportionality analysis. Reporting odds ratio (ROR) was employed to detect the potential adverse events (AEs) related to lorlatinib. The clinical characteristics, age and gender differences, time to onset of AEs were also investigated. A total of 2,941 AE reports were found to be associated with lorlatinib among the 8,818,870 AE reports obtained from the FAERS database. 167 lorlatinib-related AE signals were identified. The frequently reported AEs including hypercholesterolemia, oedema, and cognitive disorder were in line with those observed in clinical trials and drug instruction. However, AEs such as interstitial lung disease and AV block indicated in the drug label require further evaluation. More attention should be paid to the new potential unexpected AEs including pulmonary arterial hypertension and radiation necrosis. Furthermore, we examined the specific high-risk AEs of different ages and genders. In addition, majority of AEs occurred within the first 2months after lorlatinib initiation with a median onset time of 51days. Our study provides valuable insight into the post-marketing safety profile of lorlatinib, which can potentially benefit the rational and safe administration of lorlatinib in the clinic. Further prospective studies are needed to validate the associations between lorlatinib and the identified AEs.

Efficacy and safety of SY-5007, a highly potent and selective RET inhibitor, in Chinese patients with advanced RET-fusion positive non-small cell lung cancer (NSCLC): Results from a multicenter, single-arm, phase II study.

Efficacy and safety of SY-5007, a highly potent and selective RET inhibitor, in Chinese patients with advanced<i> RET</i>-fusion positive non-small cell lung cancer (NSCLC): Results from a multicenter, single-arm, phase II study.

A multicenter, prospective phase II trial of first-line osimertinib treatment for patients with poor performance status and EGFR mutation–positive non-small cell lung cancer (OPEN/TORG2040).

A multicenter, prospective phase II trial of first-line osimertinib treatment for patients with poor performance status and <i>EGFR</i> mutation–positive non-small cell lung cancer (OPEN/TORG2040).

A phase II, open-label, single-arm, multicenter, efficacy and safety study of 80 mg osimertinib in patients with leptomeningeal metastases (LM) associated with epidermal growth factor receptor (EGFR) mutation–positive non-small cell lung cancer (NSCLC): BLOSSOM.

A phase II, open-label, single-arm, multicenter, efficacy and safety study of 80 mg osimertinib in patients with leptomeningeal metastases (LM) associated with epidermal growth factor receptor (EGFR) mutation–positive non-small cell lung cancer (NSCLC): BLOSSOM.

Real-world osimertinib pretreatment experience in patients with epidermal growth factor receptor T790M mutation-positive locally advanced or metastatic non-small cell lung cancer.

Osimertinib has demonstrated efficacy in patients with epidermal growth factor receptor (EGFR) T790M-positive non-small cell lung cancer (NSCLC) in clinical trials. However, real-world data on its effectiveness remain scarce. Taiwanese patients with T790M-positive locally advanced or metastatic NSCLC and progressive disease following treatment with at least one EGFR tyrosine kinase inhibitor (TKI) were enrolled from the osimertinib early access program. Of the 419 patients (mean age, 63 years; female, 67%), 53% were heavily pretreated (≥ third-line [3L]), making osimertinib a fourth-line (4L) intervention. The median progression-free survival (PFS) was 10.5 months (95% confidence interval [CI]: 8.95-11.41); the 18-month PFS rate was 26.5%. The median overall survival (OS) was 19.0 months (95% CI: 16.30-20.95); the 24-month OS rate was 40.9%. The objective response rate was 32.46%, and the disease control rate was 86.38%. The median time to treatment discontinuation of osimertinib monotherapy was 11.9 months (95% CI: 10.49-13.11). Subgroup analyses of median PFS and OS in the chemotherapy combination group vs. the osimertinib monotherapy group yielded no difference. Central nervous system (CNS) metastasis, number of prior lines of therapy, and types of initial EGFR-TKIs did not significantly impact outcomes. The median PFS values were 9.0 (95% CI: 5.18-11.34) and 10.9 (95% CI: 9.18-11.90) months with and without CNS metastasis, respectively, and 10.8 (95% CI: 8.59-12.69), 13.6 (95% CI: 10.89-16.3), and 9.2 (95% CI: 7.8-10.62) months for second-line (2L), 3L, and ≥4L therapy, respectively. In patients who received osimertinib as 2L therapy, the median PFS values in response to prior afatinib, erlotinib and gefitinib treatment were 11.2 (95% CI: 4.85-4.79), 10.5 (95% CI: 8.59-20.26) and 8.7 (95% CI: 7.21-16.79) months, respectively. Overall, real-world data from Taiwan support the clinical benefits of osimertinib in EGFR T790M -positive NSCLC.

Prognostic value of skeletal muscle measured by CT at the T4 level in advanced EGFR-positive non-small cell lung cancer patients treated with ecotinib

Objective: To investigate the prognostic value of skeletal muscle measured by CT at the level of the fourth thoracic vertebra (T4) in advanced epidermal growth factor receptor (EGFR)-positive non-small cell lung cancer (NSCLC) patients treated with ecotinib. Methods: The study retrospectively reviewed clinical and pathological characteristics of 176 patients with advanced EGFR-positive NSCLC who received ecotinib and underwent chest CT scans at Wuhan Union Hospital between January 2017 and October 2020. Among them, 70 were male and 106 were female, with ages ranging from 27 to 80 (58.6±10.6) years. As of August 21, 2021, the median follow-up duration was 19.2 months (95%CI: 15.3 to 23.7 months). The optimal cut-off value of skeletal muscle density (T4-SMD) on CT images at the T4 level were determined using X-tile software. Kaplan-Meier analysis and log-rank test were used to plot progression-free survival curves. Cox proportional hazards regression models were employed to analyze factors influencing 1-year progression-free survival (PFS), and a nomogram prognostic model was constructed accordingly. Receiver operating characteristic (ROC) curves, calibration curves, and decision curve analysis (DCA) were utilized to evaluate the predictive value of the nomogram. Results: The T4-SMD [M (Q1,Q3)] of 176 patients was 42.56 (37.05, 45.93) HU. Patients were divided into low T4-SMD group (n=122) and high T4-SMD group (n=54) based on the cut-off value (The values for males and females were 49.44 and 41.41 HU, respectively) of T4-SMD. The median PFS time and 1-year PFS rate in the low T4-SMD group were significantly lower than those in the high T4-SMD group [10.4 (95%CI: 9.3-11.8) vs 13.7 (95%CI: 11.1-18.5) months, 36.1% vs 59.3%, respectively, P=0.034]. Eastern Cooperative Oncology Group performance status (HR=3.308, 95%CI: 1.183-9.247, P=0.023), lactate dehydrogenase level (HR=1.852, 95%CI: 1.037-3.307, P=0.037), systemic immune-inflammation index (HR=1.772, 95%CI: 1.019-3.080, P=0.043), and T4-SMD (HR=0.563, 95%CI: 0.325-0.974, P=0.040) were prognostic factors for 1-year PFS in advanced EGFR-positive NSCLC patients treated with ecotinib. A nomogram for predicting 1-year PFS of advanced EGFR-positive NSCLC patients treated with ecotinib was constructed based on the four indicators selected by multivariate Cox regression analysis. The area under the ROC curve of the nomogram was 0.775 (95%CI: 0.676-0.874). The calibration curve showed good consistency between the predicted and actual 1-year PFS. DCA demonstrated good clinical prediction effectiveness of the nomogram. Conclusion: Low T4-SMD is a prognostic risk factor for patients with advanced EGFR-positive NSCLC receiving icotinib therapy.

Osimertinib in combination with anti-angiogenesis therapy presents a promising option for osimertinib-resistant non-small cell lung cancer

BackgroundOsimertinib has become standard care for epidermal growth factor receptor (EGFR)-positive non-small cell lung cancer (NSCLC) patients whereas drug resistance remains inevitable. Now we recognize that the interactions between the tumor and the tumor microenvironment (TME) also account for drug resistance. Therefore, we provide a new sight into post-osimertinib management, focusing on the alteration of TME.MethodsWe conducted a retrospective study on the prognosis of different treatments after osimertinib resistance. Next, we carried out in vivo experiment to validate our findings using a humanized mouse model. Furthermore, we performed single-cell transcriptome sequencing (scRNA-seq) of tumor tissue from the above treatment groups to explore the mechanisms of TME changes.ResultsTotally 111 advanced NSCLC patients have been enrolled in the retrospective study. The median PFS was 9.84 months (95% CI 7.0–12.6 months) in the osimertinib plus anti-angiogenesis group, significantly longer than chemotherapy (P = 0.012) and osimertinib (P = 0.003). The median OS was 16.79 months (95% CI 14.97–18.61 months) in the osimertinib plus anti-angiogenesis group, significantly better than chemotherapy (P = 0.026), the chemotherapy plus osimertinib (P = 0.021), and the chemotherapy plus immunotherapy (P = 0.006).The efficacy of osimertinib plus anlotinib in the osimertinib-resistant engraft tumors (R-O+A) group was significantly more potent than the osimertinib (R-O) group (P<0.05) in vitro. The combinational therapy could significantly increase the infiltration of CD4+ T cells (P<0.05), CD25+CD4+ T cells (P<0.001), and PD-1+CD8+ T cells (P<0.05) compared to osimertinib.ScRNA-seq demonstrated that the number of CD8+ T and proliferation T cells increased, and TAM.mo was downregulated in the R-O+A group compared to the R-O group. Subtype study of T cells explained that the changes caused by combination treatment were mainly related to cytotoxic T cells. Subtype study of macrophages showed that proportion and functional changes in IL-1β.mo and CCL18.mo might be responsible for rescue osimertinib resistance by combination therapy.ConclusionsIn conclusion, osimertinib plus anlotinib could improve the prognosis of patients with a progressed disease on second-line osimertinib treatment, which may ascribe to increased T cell infiltration and TAM remodeling via VEGF-VEGFR blockage.

Osimertinib plus local treatment for brain metastases versus osimertinib alone in patients with EGFR-Mutant Non-Small Cell Lung Cancer

ObjectivesOsimertinib is a standard treatment for patients with EGFR-mutant non-small cell lung cancer (NSCLC) and is highly effective for brain metastases (BMs). However, it is unclear whether local treatment (LT) for BMs prior to osimertinib administration improves survival in EGFR-mutant NSCLC. We aimed to reveal the survival benefit of upfront local treatment (LT) for BMs in patients treated with osimertinib. Materials and MethodsThis multicenter retrospective study included consecutive patients with EGFR mutation (19del or L858R)-positive NSCLC who had BMs before osimertinib initiation between August 2018 and October 2021. We compared overall survival (OS) and central nervous system progression-free survival (CNS-PFS) between patients who received upfront LT for BMs (the upfront LT group), and patients who received osimertinib only (the osimertinib-alone group). Inverse-probability treatment weighting (IPTW) analysis was performed to adjust for potential confounding factors. ResultsOf the 121 patients analyzed, 57 and 64 patients had 19del and L858R, respectively. Forty-five and 76 patients were included in the upfront LT group and the osimertinib-alone groups, respectively. IPTW-adjusted Kaplan–Meier curves showed that the OS of the upfront LT group was significantly longer than that of the osimertinib-alone group (median, 95 % confidence intervals [95 %CI]: Not reached [NR], NR–NR vs. 31.2, 21.7–33.2; p = 0.021). The hazard ratio (HR) for OS and CNS-PFS was 0.37 (95 %CI, 0.16–0.87) and 0.36 (95 %CI, 0.15–0.87), respectively. ConclusionsThe OS and CNS-PFS of patients who received upfront LT for BMs followed by osimertinib were significantly longer than those of patients who received osimertinib alone. Upfront LT for BMs may be beneficial in patients with EGFR-mutant NSCLC treated with osimertinib.

Abstract 5839: Identification of low-dose ligand dependent drug-resistance in ALK/ROS1 positive NSCLC via CRISPR library screening

Abstract Tyrosine kinase inhibitor (TKI) therapy has displayed significant effectiveness in treating patients with anaplastic lymphoma kinase (ALK) and ROS proto-oncogene 1 (ROS1)-positive non-small cell lung cancer (NSCLC). Nonetheless, the emergence of acquired resistance in most patients presents a major challenge. Drug-tolerant persister (DTP) cells have recently gained attention as potential sources of resistance, highlighting the need for a deeper understanding of drug resistance mechanisms. To address this issue, a comprehensive genome-wide CRISPR-Cas9 knockout screening was conducted using an ALK-positive NSCLC cell line derived from pleural effusion in a patient who had not been exposed to ALK-TKI treatment. Following a 9-day ALK-TKI treatment, sequencing analysis was performed to identify sgRNAs in DTP cells. Notably, this analysis detected the involvement of tumor suppressor genes, including NF2, BAX, and ERRFI1.NF2 depletion was found to induce a substantial resistance to ALK-TKIs, and a combination therapy involving mTOR inhibitors showed promise in partially overcoming this resistance. Moreover, knockout of ERRFI1 or BAX led to an increase in DTP cells, drawing particular attention to ERRFI1, also known as MIG6, which is known for negatively regulating EGFR signaling. One intriguing discovery was that the loss of MIG6 induced resistance to ALK-TKIs when exposed to a relatively low dose of EGF, comparable to concentrations in plasma of healthy adults. This resistance was attributed to the upregulation of the MAPK and PI3K/Akt/mTOR pathways. Similar to ALK-rearranged NSCLC, ROS1 fusion-positive NSCLC cell lines also showed resistance by MIG6 knockout. Interestingly, some cell lines with reduced MIG6 expression tended to develop resistance with low-dose EGF, even without prior treatment, and overexpression of MIG6 restored sensitivity to TKIs. We further explored the potential of combination therapy, combining ALK-TKIs with anti-EGFR antibodies, and this approach effectively addressed acquired resistance in both in vivo and in vitro models. Furthermore, an analysis of clinical samples revealed that individuals resistant to ALK-TKIs displayed decreased mRNA MIG6 levels in comparison to their sensitive counterparts. Investigating the mechanisms behind MIG6 expression, we confirmed that ALK-TKI therapy suppressed MIG6 expression levels, while factors such as corticosteroid usage or exposure to hypoxia induced the upregulation of MIG6, potentially influencing the formation of DTP cells. In conclusion, this research has unveiled a novel factor contributing to resistance in ALK and ROS1-TKI therapies by activating the EGFR pathway through exposure to low-dose ligands, shedding light on potential therapeutic strategies to combat acquired resistance. Citation Format: Nobuyuki Kondo, Takahiro Utsumi, Ken Uchibori, Yasunari Miyazaki, Ryohei Katayama. Identification of low-dose ligand dependent drug-resistance in ALK/ROS1 positive NSCLC via CRISPR library screening [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 5839.