Epidermal Growth Factor Receptor Mutant Non-small Cell Lung Research Articles

Loss of CDKN2A Enhances the Efficacy of Immunotherapy in EGFR Mutant Non-Small Cell Lung Cancer

Abstract Mutant epidermal growth factor receptor (EGFR) is a common driver of non-small cell lung cancer (NSCLC). While mutant EGFR has been reported to limit the efficacy of immunotherapy, a subset of EGFR mutant NSCLC patients benefit from treatment with immune checkpoint inhibitors. A better understanding of how co-occurring genomic alterations in oncogenic driver genes impact immunotherapy efficacy may provide a more complete understanding of cancer heterogeneity and identify biomarkers of response. Here, we investigated the effects of frequent EGFR co-mutations in EGFR mutant lung cancer models and identified loss-of-function mutation of CDKN2A as a potential sensitizer to anti-PD-1 treatment in vitro and in vivo. Mechanistically, CDKN2A loss impacted the composition of the tumor immune microenvironment (TIME) by promoting the expression of PD-L2 through reduced ubiquitination of c-Myc, and mutant EGFR cooperated to upregulate c-Myc and PD-L2 by activating the MAPK pathway. Blocking PD-L2 induced anti-tumor immune responses mediated by CD8+ T cells in EGFR/CDKN2A co-mutated lung cancer. Importantly, a small-molecule PD-L2 inhibitor, zinc undecylenate, remodeled the TIME of EGFR/CDKN2A co-mutant tumors and enhanced the anti-tumor efficacy of EGFR-tyrosine kinase inhibitors. Collectively, these results identify EGFR/CDKN2A co-mutation as a distinct subtype of NSCLC that shows superior sensitivity to immune checkpoint blockade and reveals a potential combined therapeutic strategy for treating this NSCLC subtype.

Therapeutic drug monitoring of osimertinib in EGFR mutant non-small cell lung cancer by dried blood spot and plasma collection: A pilot study.

Therapeutic drug monitoring (TDM) has led to significant improvements in individualized medical care, although its implementation in oncology has been limited to date. Tyrosine kinase inhibitors (TKIs) are a group of therapies for which TDM has been suggested. Osimertinib is one such therapy used in the treatment of epidermal growth factor receptor (EGFR) mutation-driven lung cancer. Herein, we describe a prospective pilot study involving 21 patients on osimertinib primarily as a preliminary evaluation of drug levels in a real-world setting. Concentrations of the drug and its primary metabolites were measured with a validated liquid chromatography-mass spectrometry (LC-MS) assay across serial timepoints. As part of this study, inter-individual variability by dose and ethnicity as well as intra-individual variability across timepoints are explored. Furthermore, we attempted to validate dried blood spot (DBS)-based quantitation as an accurate alternative to plasma quantitation. Successful quantitation of osimertinib and primary metabolites was achieved for our subjects. Compound plasma levels were highly correlated to DBS levels. There was no significant difference in concentrations with ethnicity or dosing or intra-individual variability across timepoints. As such, we demonstrate that TDM for osimertinib is practical for future trials. We also validated the use of DBS as an alternative to conventional quantitation for exploration of TDM for osimertinib in larger trials and for other targeted therapies.

Abstract 4759: Targeting slow-cycling persisters in EGFR mutant non-small cell lung cancer

Abstract Activating mutations in the epidermal growth factor receptor (EGFR) gene in non-small cell lung cancer (NSCLC) patients are associated with clinical benefit in the metastatic and adjuvant settings when treated with EGFR inhibitors, such as osimertinib. Despite its dramatic efficacy, most patients are partial responders and refractive disease leave limited treatment options. The objective was to dissect the mechanism of osimertinib resistance in EGFR mutant NSCLC models to identify a means of re-sensitization. Imaging mass cytometric analysis of 76 NSCLC patients demonstrated EGFR expression was inversely correlated to CD105 membrane expression. CD105 is a transforming growth factor beta (TGF-β) family co-receptor that promotes bone morphogenic protein (BMP) signaling and inhibits TGF-β signaling. Significant elevation in cell surface CD105 by osimertinib was furthered by EGFR knockdown in two NSCLC lines with EGFR activating mutations. These lines were subjected to a program of increasing osimertinib concentrations to generate isogenic resistant lines. Heterogeneous drug-tolerant persister cells had significantly higher mutational load, increased CD105 cell surface expression as well as greater expression of bypass signaling factors such as ERK, PI3K, and BMP ligands compared to their parental counterparts. Single cell RNA-seq analysis of parental NSCLC revealed a small population of cells that shared elevated endothelial and pyrimidine metabolism, with a slow-cycling signature that was enriched in the osimertinib-resistant cells. Combining osimertinib with a CD105 neutralizing antibody, carotuximab, reduced the slow-cycling population and restored osimertinib sensitivity in resistant cell lines. The knockdown of CD105 had a more pronounced decrease in cell viability when combined with osimertinib. The osimertinib-resistant lines demonstrated more condensed chromatin and glycolytic state compared to the respective parental lines by ATAC-seq and Single Cell ENergetIc metabolism profiling, respectively. The addition of carotuximab reversed the chromatin and metabolic reprograming of osimertinib resistance. Carotuximab was discovered to initiate CD105 interaction with EGFR and its dominant active variant, EGFRv3. Ultimately, combination therapy of carotuximab and osimertinib resulted in significantly reduced tumor expansion compared to mice treated with either drug alone. Paradoxically, the small tumors from combination therapy had greater mitosis compared to the larger tumors of the osimertinib single agent treated mice. Inhibition of CD105 with carotuximab can overcome resistance to osimertinib and inhibit NSCLC tumor progression. This is a first-in-class pre-clinical foundation for a novel synthetic lethality treatment strategy resulting from the observation of global changes in EGFR-antagonist resistance as opposed to individual mutations identified in tumor subpopulations. Citation Format: Manish Thiruvalluvan, Sandrine Billet, Zhenqiu Liu, Joseph Lownik, Gabrielle Gonzales, Hyoyoung Kim, Anton L. Villamejor, Larry Milshteyn, Kamya Sankar, Edwin M. Posadas, Jean Lopategui, Sungyong You, Karen Reckamp, Neil A. Bhowmick. Targeting slow-cycling persisters in EGFR mutant non-small cell lung cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 4759.

AXIN1/MYC Axis Mediated the Osimertinib Resistance in EGFR Mutant Non-Small Cell Lung Cancer Cells.

Osimertinib, a promising and approved third-generation epidermal growth factor receptor (EGFR) tyrosine kinase inhibitor (TKI), is a standard strategy for EGFR-mutant non-small cell lung cancer (NSCLC) patients. However, developed resistance is unavoidable, which reduces its long-term effectiveness. In this study, RNA sequencing was performed to analyze differentially expressed genes (DEGs). The PrognoScan database and Gene Expression Profiling Interactive Analysis (GEPIA) were used to identify the key genes for clinical prognosis and gene correlation respectively. Protein expression was determined by western blot analysis. Cell viability assay and Ki67 staining were used to evaluate the effect of osimertinib on tumor cells. Finally, we screened out two hub genes, myelocytomatosis oncogene (Myc) and axis inhibition protein 1 (Axin1), upregulated in three osimertinib-resistant cell lines through RNA sequencing and bioinformatics analysis. Next, cell experiment confirmed that expression of C-MYC and AXIN1 were elevated in different EGFR mutant NSCLC cell lines with acquired resistance to osimertinib, compared with their corresponding parental cell lines. Furthermore, we demonstrated that AXIN1 upregulated the expression of C-MYC and mediated the acquired resistance of EGFR mutant NSCLC cells to osimertinib in vitro. In conclusion, AXIN1 affected the sensitivity of EGFR mutant NSCLC to osimertinib via regulating C-MYC expression in vitro. Targeting AXIN1/MYC signaling may be a potential new strategy for overcoming acquired resistance to osimertinib.

Systematic evaluation of clinical efficacy of CYP1B1 gene polymorphism in EGFR mutant non-small cell lung cancer observed by medical image.

Lung cancer is the cancer with the highest mortality rate and the highest incidence in the world at this stage. Among them, non-small lung cancer is the most common type of lung cancer, and most small cancers have disappeared, which is the optimal time for surgery at the time of diagnosis. To explore and systematically evaluate the clinical efficacy of CYP1B1 gene polymorphism in the treatment of epidermal growth factor receptor (EGFR) Mutant non-small cell lung cancer, this article proposes the principles of lung cancer screening based on CYP1B1 gene polymorphism and polarization imaging and explores the diagnosis and treatment of non-EGFR mutant lung cancer. Based on a large number of medical image data, imageomics can directly reflect the correlation between tumor molecular phenotype and image characteristics by deeply mining some imaging features of the image, which has important value in the early diagnosis of disease, the formulation of personalized treatment plan, and efficacy evaluation and prognosis prediction. A total of 141 NSCLC patients with sensitive EGFR mutation were included in this study, including 101 patients with EGFR single-gene mutation and 40 patients with EGFR multigene mutation coexisting mutation. Both groups of patients were female, aged ≥60 years, no smoking history, no family history of leukemia, adenocarcinoma, lung cancer, stage IV, lymph node metastasis, living, far from metastasis, and ECOG score of 0-2. This study examined the relative number of gene expression and PFS in EGFR multigene co-existing mutations. When the number of mixed genes is 1, 2, and higher, the PFS is 9 months, 8 months, and 6 months, respectively. The PFS time of this group of patients gradually shortened. Therefore, this study examined the benefit of polygenic mutation in estimation by comparing the clinical characteristics of patients with EGFR single-gene mutation and polygenic mutation, to provide measurement of EGFR-TKI and to provide suggestions for future drug selection.

Overview on Therapeutic Options in Uncommon EGFR Mutant Non-Small Cell Lung Cancer (NSCLC): New Lights for an Unmet Medical Need.

The majority of epidermal growth factor receptor (EGFR) mutations (85-90%) are exon 19 deletions and L858R point mutations of exon 21, characterized by high sensitivity to EGFR-tyrosine kinase inhibitors (TKIs). Less is known about uncommon mutations (10-15% of EGFR mutations). The predominant mutation types in this category include exon 18 point mutations, exon 21 L861X, exon 20 insertions, and exon 20 S768I. This group shows a heterogeneous prevalence, partly due to different testing methods and to the presence of compound mutations, which in some cases can lead to shorter overall survival and different sensitivity to different TKIs compared to simple mutations. Additionally, EGFR-TKI sensitivity may also vary depending on the specific mutation and the tertiary structure of the protein. The best strategy remains uncertain, and the data of EGFR-TKIs efficacy are based on few prospective and some retrospective series. Newer investigational agents are still under study, and there are no other approved specific treatments targeting uncommon EGFR mutations. Defining the best treatment option for this patient population remains an unmet medical need. The objective of this review is to evaluate existing data on the outcomes, epidemiology, and clinical characteristics of lung cancer patients with rare EGFR mutations, with a focus on intracranial activity and response to immunotherapy.

Pre-radiotherapy systemic immune inflammation index associated with overall survival in patients with advanced EGFR mutant non-small cell lung cancer receiving thoracic radiotherapy

PurposeThis study aimed to investigate the prognostic potential of the pre-radiotherapy systemic immune-inflammation index (SII) for the survival of advanced lung adenocarcinoma patients with epidermal growth factor receptor (EGFR) mutations, which might provide a basis for optimizing the comprehensive treatment scheme.MethodsA total of 111 lung adenocarcinoma patients with EGFR mutations, who received thoracic radiotherapy, were included in this retrospective study. The primary endpoint of the study was based on the overall survival (OS) of patients. The receiver operating characteristic (ROC) curve analysis was performed to determine the optimal cut-off value of each immune inflammation index. Kaplan–Meier analysis was performed for the comparison of OS. The Cox proportional-hazard model was used for the multivariate and univariate regression analyses to determine the correlations of prognostic factors with the disease.ResultsSII was divided into the high SII group (≥ 620.2; 45.95%) and the low SII group (SII < 620.2; 54.05%) based on the optimal cutoff values. The median OS rates were 53.3 and 33.3 months in the low and high SII groups, respectively, showing statistically significant differences ( hazard ratio (HR) = 0.459; 95% CI 0.286–0.736; P < 0.001). The multivariate analysis showed that, after adjusting for the significant covariates, the SII values were independently associated with the improved OS of the patients (adjusted HR = 0.444; 95% CI 0.279–0.709; P = 0.001). The low NLR values were associated with the better OS of patients (HR = 0.509; 95% CI 0.326–0.792; P = 0.005) and vice versa (HR = 0.422; 95% CI 0.213–0.836; P < 0.001). The patients in the low LMR group before radiotherapy exhibited longer OS as compared to those in the high LMR group (HR = 0.497; 95% CI 0.308–0.802; P = 0.001).ConclusionsThis study showed that these inflammatory indices might have an important prognostic potential for advanced lung adenocarcinoma patients with EGFR mutations, receiving thoracic radiotherapy and might provide a basis for the individualized treatment of these patients.

1186TiP EPONA, efficacy of osimertinib with platinum and pemetrexed in EGFR mutant non-small cell lung cancer patients bearing CNS metastasis, and have systemic progression but stable intracranial disease on OsimertiNib resistAnce (TORG 1938)

Central nervous system (CNS) protection is a crucial strategy for the long-term survival of patients (pts) with cancer. Currently, pts with epidermal growth factor receptor (EGFR)-mutant (mt) non-small cell lung cancer (NSCLC) have expected longer survival after treatment with EGFR-TKIs. Osimertinib is a current standard of care (SOC) for EGFR-mt NSCLC and has been clinically shown to control the CNS progression. The current SOC involves switching to platinum doublet chemotherapy and discontinuing osimertinib if the CNS is under control after progression at other sites.

1013P Utilizing a combined biomarker and therapeutic strategy to reverse TKI resistance in EGFR mutant non-small cell lung cancer

Tyrosine kinase inhibitors (TKIs) are first-line therapy for non-small-cell lung cancers (NSCLC) that harbor sensitizing mutations within the epidermal growth factor receptor (EGFR). However, resistance to TKIs such as Osimertinib remain a primary issue. Herein, we have identified the protein cell division cycle associated protein-3 (CDCA3) as a potential biomarker for TKI sensitivity and a unique therapeutic approach to target TKI resistance.

EP08.02-063 SANOVO: A Phase 3 Study of Savolitinib or Placebo in Combination with Osimertinib in Patients with EGFR-mutant and MET Overexpressed NSCLC

Epidermal growth factor receptor (EGFR) tyrosine kinase inhibitors (TKIs) have improved clinical outcomes for patients with EGFR mutant (EGFRm) non-small cell lung cancer (NSCLC); however, patients will inevitably progress often due to acquired resistance mutations. Coexisting MET overexpression is known to be associated with resistance to EGFR TKIs. Savolitinib is a potent and highly selective oral MET TKI that has shown encouraging antitumor activity and a favorable safety profile in patients with pulmonary sarcomatoid carcinoma and other NSCLC with MET exon 14 skipping alterations in a phase 2 study (NCT02897479).

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

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

Small-molecule targeted therapies induce dependence on DNA double-strand break repair in residual tumor cells.

Residual cancer cells that survive upfront drug treatments act as a reservoir from which eventual resistant disease emerges. Although there is great interest in therapeutically targeting residual cells, efforts to do so are hampered by our limited knowledge of the vulnerabilities existing in this cell state. Here, we report that diverse oncogene-targeted therapies, including inhibitors of epidermal growth factor receptor (EGFR), anaplastic lymphoma kinase (ALK), KRAS, and BRAF, induce DNA double strand breaks and consequently, ataxia-telangiectasia mutated (ATM)-dependent DNA repair in oncogene-matched residual tumor cells. This DNA damage response, observed in cell lines, mouse xenograft models, and human patients, is driven by a pathway involving the activation of caspases 3 and 7 and the downstream caspase-activated deoxyribonuclease (CAD). CAD is, in turn, activated through caspase-mediated degradation of its endogenous inhibitor, ICAD. In models of EGFR mutant non-small cell lung cancer (NSCLC), tumor cells that survive treatment with small-molecule EGFR-targeted therapies are thus synthetically dependent on ATM, and combined treatment with an ATM kinase inhibitor eradicates these cells in vivo. This led to more penetrant and durable responses in EGFR mutant NSCLC mouse xenograft models, including those derived from both established cell lines and patient tumors. Last, we found that rare patients with EGFR mutant NSCLC harboring co-occurring, loss-of-function mutations in ATM exhibit extended progression-free survival on first generation EGFR inhibitor therapy relative to patients with EGFR mutant NSCLC lacking deleterious ATM mutations. Together, these findings establish a rationale for the mechanism-based integration of ATM inhibitors alongside existing targeted therapies.

1192MO Amivantamab monotherapy and in combination with lazertinib in post-osimertinib EGFR-mutant NSCLC: Analysis from the CHRYSALIS study

Amivantamab (ami), an epidermal growth factor receptor (EGFR)-MET bispecific antibody, has demonstrated efficacy in EGFR mutant non-small cell lung cancer (NSCLC) that progressed on osimertinib (osi), both as monotherapy and in combination with lazertinib (laz), a 3rd-generation tyrosine kinase inhibitor. Clinical outcomes of patients (pts) treated with ami monotherapy (mono) and ami in combination with laz (combo) are presented here. CHRYSALIS is an ongoing study of ami in pts with advanced EGFR mutant NSCLC (NCT02609776). Pts who progressed on osi were pooled to form the mono group, a majority of whom were preselected for C797S/other resistance mutations or MET amplification. The combo group comprised unselected pts who had progressed on osi but were chemotherapy-naïve. Response was assessed by the investigator per RECIST v1.1. As of 19 Apr 2021, 121 pts in the mono group (85% with EGFR/MET-based resistance) and 45 in the combo group (38% with EGFR/MET-based resistance) were efficacy-evaluable, with median follow-up of 6.9 and 11.1 months, respectively. Antitumor activity was observed in the mono group, with 33 achieving partial response (PR) as best response, of which 23 were confirmed, for an overall response rate (ORR) of 19% (95% CI, 12–27). In the combo group, 1 complete response and 15 PRs were observed, all of which confirmed, for an ORR of 36% (95% CI, 22–51). Median duration of response was 5.9 months with mono, 9.6 months with combo (Table). The safety profile for both mono and combo was consistent with previously-reported safety. No new safety signals were identified. Antitumor activity of ami + laz in the post-osi setting appears favorable even without molecular selection post osimertinib failure, supporting that simultaneous targeting of the extracellular and catalytic domains of EGFR provides additive benefits.Table: 1192MOEfficacy of amivantamab monotherapy and in combination with lazertinib among efficacy-evaluablea patientsEfficacyMonotherapy (n=121)Combination (n=45)ORR (95% CI)19% (12–27)36% (22–51)CBR (95% CI)48% (39–57)64% (49–78)mDOR, month (95% CI)5.9 (4.2–12.6)9.6 (5.3–NR)aPatients who had at least 2 post-baseline disease assessment or discontinued before the second assessment. CBR, clinical benefit rate (complete response, partial response, or stable disease of at least 11 weeks); mDOR, median duration of response; ORR, overall response rate; NR, not reached Open table in a new tab

An in vitro model of tumor heterogeneity resolves genetic, epigenetic, and stochastic sources of cell state variability.

Tumor heterogeneity is a primary cause of treatment failure and acquired resistance in cancer patients. Even in cancers driven by a single mutated oncogene, variability in response to targeted therapies is well known. The existence of additional genomic alterations among tumor cells can only partially explain this variability. As such, nongenetic factors are increasingly seen as critical contributors to tumor relapse and acquired resistance in cancer. Here, we show that both genetic and nongenetic factors contribute to targeted drug response variability in an experimental model of tumor heterogeneity. We observe significant variability to epidermal growth factor receptor (EGFR) inhibition among and within multiple versions and clonal sublines of PC9, a commonly used EGFR mutant nonsmall cell lung cancer (NSCLC) cell line. We resolve genetic, epigenetic, and stochastic components of this variability using a theoretical framework in which distinct genetic states give rise to multiple epigenetic "basins of attraction," across which cells can transition driven by stochastic noise. Using mutational impact analysis, single-cell differential gene expression, and correlations among Gene Ontology (GO) terms to connect genomics to transcriptomics, we establish a baseline for genetic differences driving drug response variability among PC9 cell line versions. Applying the same approach to clonal sublines, we conclude that drug response variability in all but one of the sublines is due to epigenetic differences; in the other, it is due to genetic alterations. Finally, using a clonal drug response assay together with stochastic simulations, we attribute subclonal drug response variability within sublines to stochastic cell fate decisions and confirm that one subline likely contains genetic resistance mutations that emerged in the absence of drug treatment.

CHRYSALIS-2: A phase 1/1b study of lazertinib as monotherapy and in combination with amivantamab in patients with EGFR-mutant NSCLC.

TPS9132 Background: Epidermal growth factor receptor (EGFR) tyrosine kinase inhibitors (TKIs) have improved clinical outcomes for patients with EGFR mutant (EGFRm) non-small cell lung cancer (NSCLC); however, patients will inevitably progress due to acquired resistance mutations. Lazertinib is a potent, brain-penetrant, 3rd-generation EGFR TKI with efficacy against activating EGFR and resistance T790M mutations. Amivantamab is an EGFR-MET bispecific antibody with immune cell-directing activity that targets activating EGFR and MET mutations. Synergistic inhibition of the EGFR by targeting the receptor’s extracellular domain with amivantamab and the kinase domain with lazertinib, may lead to more potent inhibition of the EGFR pathway and potentially delay resistance. In the ongoing CHRYSALIS phase 1 study (NCT02609776), preliminary antitumor activity has been demonstrated with the combination of lazertinib and amivantamab in patients with treatment-naïve and osimertinib-relapsed EGFRm NSCLC (Cho Ann Oncol 2020;31:S813). Methods: CHRYSALIS-2 is an ongoing phase 1/1b open-label study of lazertinib as monotherapy and in combination with amivantamab in patients with advanced EGFRm NSCLC (NCT04077463; https://clinicaltrials.gov/ct2/show/NCT04077463 ). Phase 1 of the study has confirmed the safety and tolerability of lazertinib monotherapy in Japanese patients. The objective of phase 1b is to characterize the preliminary efficacy of lazertinib in combination with amivantamab in subpopulations of patients with EGFRm NSCLC (Phase 1b Expansion Cohorts) at the recommended combination dose of 1050 mg (1400 mg, ≥80 kg) IV amivantamab dosed weekly in cycle 1 (28-day cycle), every other week thereafter, and 240 mg oral lazertinib QD. Global enrollment in Phase 1b Expansion Cohorts is currently ongoing. Expansion Cohort A is enrolling patients who have progressed on 1st or 2nd-line osimertinib followed by platinum chemotherapy; Expansion Cohort B is enrolling patients with EGFR exon 20 insertion (Exon20ins) mutation who have progressed on prior therapy; and Expansion Cohort C is enrolling patients with uncommon non-Exon20ins EGFR mutations (i.e., S768I, L861Q, G719X) who are treatment-naïve or received 1st or 2nd-generation EGFR TKI as last therapy. The primary endpoints of the study are frequency of dose-limiting toxicity for phase 1 and 1b combination cohorts, and overall response rate for phase 1b expansion cohorts. Key secondary endpoints include safety (adverse events), pharmacokinetics, duration of response, clinical benefit rate, progression-free survival, and overall survival. Safety assessments will include monitoring AEs, clinical laboratory tests, ophthalmologic examination, ECG, and ECHO/MUGA. Blood samples will be collected to access PK. Tumor response will be assessed every 6 weeks by the investigator using RECIST, v1.1. Clinical trial information: NCT04077463.

P76.54 Prognostic Value of Radiotherapy Pattern for Late-Stage Epidermal Growth Factor Receptor (EGFR) Mutant Lung Adenocarcinomas

There is still no study to assess the value of radiotherapy pattern on prognosis for late-stage EGFR mutant non-small cell lung cancer. The aim of the study is to investigate the role of different pattern of local radiotherapy in the management of stage IV epidermal growth factor receptor (EGFR) mutated non-small cell lung cancers (NSCLCs) treated with EGFR tyrosine kinase inhibitors (TKIs). Patients with stage IV EGFR mutant NSCLCs treated with radiotherapy concomitant to EGFR TKIs treatment were retrospectively identified. Overall survival (OS) were analyzed as endpoints of the study. Kaplan-Meier method was used in survival analysis, and logarithmic rank test was used to compare the effects of individual variables on different results (P < 0.05 was considered to be statistically significant). A total of 205 patients were enrolled in the study from May 2010 to December 2017. 111 patients received one-time single site radiotherapy (SSR) and 94 patients received multiple sites radiotherapy (MSR). Those who received MSR had longer OS (median 40.0 months; 95% CI, 29.6 to 50.4) than those who received SSR (median 28.9 months; 95% CI, 24.3 to 33.5; P=0.031). We further analyzed the impact of different organs or sites irradiation on OS. The median OS of patients who had received thoracic radiotherapy and those who had not received thoracic radiotherapy was 41.7 months (95% CI, 29.0 to 54.4) and 27.1 months (95% CI, 22.7 to 31.5), respectively (log-rank P<0.001) (Figure). Multiple sites radiotherapy improved survival outcomes in late-stage lung adenocarcinoma patients with EGFR-sensitive mutations; further, thoracic radiotherapy played the most important role in improving prognosis.

Cholesterol synthesis disruption combined with a molecule-targeted drug is a promising metabolic therapy for EGFR mutant non-small cell lung cancer.

BackgroundAcquired resistance is a challenge for epidermal growth factor receptor (EGFR) mutant non-small cell lung cancer. Here, we propose a novel treatment strategy based on recent lipid metabolism work.MethodsWe applied a variety of experimental methods such as immunoblotting, MTT, si-RNA, and animal models, to demonstrate the relationship between EGFR and low-density lipoprotein receptor (LDLR) and the effects of statin monotherapy, and TKI monotherapy, and their combination on cell proliferation at the cell level and animal level.ResultsLDLR has a positive correlation with EGFR, EGFR signaling upregulates LDLR expression through the SREBP-1 dependent pathway, EGFR mutation cells count on lipids to survive and grow. Combined with a molecule-targeted drug, atorvastatin not only enhances the treatment effect in vitro, but also mitigates the growth of NSCLC in vivo. In this animal experiment, the combination medicine (atorvastatin with TKI) has a better tumor suppression effect on NSCLC. In HCC827 cell line, the average tumor shrinkage is about 68% in Gefitinib group, and about 49% in atorvastatin group, but about 89% in combination group. In H1975 cell line, the average tumor shrinkage is about 18% in Osimertinib group, and about 8% in atorvastatin group, but about 44% in combination group.Conclusionsthe combination of an EGFR-TKI and a statin for EGFR mutant NSCLC may be a novel tumor inhibiting treatment.

A phase II trial of durvalumab (MEDI4736) and tremelimumab with chemotherapy in metastatic EGFR mutant non-squamous non-small cell lung cancer (NSCLC) following progression on EGFR tyrosine kinase inhibitors (TKIs) (ILLUMINATE).

TPS9631 Background: Epidermal growth factor receptor (EGFR) tyrosine kinase inhibitors (TKIs) have proven remarkably effective in the treatment of advanced EGFR mutant non-small cell lung cancer (NSCLC). However, drug resistance is inevitable and outcomes with subsequent platinum-pemetrexed chemotherapy are poor. The role of immune-checkpoint inhibitor monotherapy in EGFR mutant NSCLC remains uncertain with trials demonstrating inferior survival outcomes compared to chemotherapy. However, a recent randomised study with combination checkpoint inhibitor-chemotherapy demonstrated improved survival over chemotherapy alone in this patient population. This study aims to evaluate the efficacy and tolerability of combination dual immune-checkpoint blockade, durvalumab and tremelimumab, with platinum-pemetrexed chemotherapy in metastatic EGFR mutant NSCLC following progression on EGFR-TKIs. Methods: This international phase II cohort study will recruit 100 participants from Australia and Taiwan with advanced EGFR mutant NSCLC following disease progression with EGFR-TKIs [Cohort 1 (n=50): T790M mutation negative on tissue and plasma; Cohort 2 (n=50): T790M mutation positive on tissue and/or plasma, and progression on3rd generation TKIs]. Participants will receive 4 cycles of induction durvalumab 1500mg and tremelimumab 75mg with platinum-pemetrexed chemotherapy every 3 weeks, followed by maintenance durvalumab 1500mg and pemetrexed 500mg/m2 every 4 weeks until disease progression. Response will be assessed at 6 and 12 weeks, then 8-weekly during the first year, and 12-weekly thereafter. Major endpoints include objective tumour response rate (OTRR; RECIST1.1; primary), disease control rate, OTRR (iRECIST), progression-free survival, overall survival, and adverse events. Correlative studies include biomarker assessment as potential predictive/prognostic factors. ILLUMINATE is a collaboration between the Australasian Lung Cancer Trials Group, National Health Research Institutes (Taiwan) and the NHMRC Clinical Trials Centre, University of Sydney. As of 6/2/2020, 11 of planned 100 participants have been recruited. Clinical trial information: NCT03994393 .

MiR-200c-3p suppression is associated with development of acquired resistance to epidermal growth factor receptor (EGFR) tyrosine kinase inhibitors in EGFR mutant non-small cell lung cancer via a mediating epithelial-to-mesenchymal transition (EMT) process

EGFR-mutant lung cancer inevitably develops resistance to epidermal growth factor receptor (EGFR) tyrosine kinase inhibitors (TKIs). To investigate the clinical relevance of microRNAs (miRNAs) in TKI therapy response and resistance. We performed a miRNA PCR array analysis and used The Cancer Genome Atlas (TCGA) database to identify potential miRNAs related to EGFR TKIs resistance. We then correlated miRNA expression in 70 surgical and 50 malignant pleural effusion specimens with patient outcomes in those with non-small cell lung carcinoma. Molecular manipulation was performed in EGFR mutant lung cancer cells to assess the effect of miR-200c-3p on cell migratory ability and EGFR-TKI sensitivity. We identified miR-200c-3p and miR-203a-3p as potential EGFR TKI resistance regulators via their modulation of epithelial-to-mesenchymal transition (EMT). MiR-200c-3p and miR-203a-3p were down-regulated in EGFR TKI-resistant cell lines. Progression-free survival (PFS) with EGFR-TKI treatment of patients with high miR-200c-3p expression, but not miR-203a-3p, in the specimens was significantly longer than that of patients with low expression. MiR-200c-3p overexpression inhibited the EMT process in EGFR TKI resistance cell lines and promoted cell death. MiR-200c-3p silencing in EGFR TKI sensitive cell lines increased drug resistance. MiR-200c-3p plays a role in sensitivity to EGFR TKIs via modulating EMT process.

Serum CRIPTO does not confer drug resistance against osimertinib but is an indicator of tumor burden in non-small cell lung cancer

BackgroundAdenocarcinoma is the most common subtype of non-small cell lung cancer (NSCLC) and often harbors oncogenic driver mutations in the epidermal growth factor receptor (EGFR). Osimertinib (AZD9291), a third generation EGFR TKI, has replaced earlier generation EGFR TKIs for first line treatment of EGFR mutant lung cancer due to its improved overall survival, longer progression free survival, and better tolerability compared to earlier generation inhibitors. However, like earlier generation EGFR TKIs, only about two thirds of patients respond, indicating an unknown mechanism of intrinsic resistance for the non-responders. We previously identified overexpression of CRIPTO as a potential mechanism of intrinsic resistance to EGFR TKIs of first and second generation. ObjectiveTo determine if CRIPTO could promote drug resistance against the third generation EGFR-TKIs osimertinib. We also wanted to investigate whether this resistance was conferred by both membrane bound and secreted CRIPTO. Finally, we wanted to explore the potential of secreted CRIPTO as a non-invasive biomarker for EGFR-TKI resistance. Materials and methodsHCC827 and H1975, EGFR mutant non-small cell lung carcinoma (NSCLC) cell lines, were transfected with wildtype CRIPTO, two secreted variants of CRIPTO, a membrane only version of CRIPTO, and the mock backbone vector as the control. Western blotting, immunoprecipitation, and in vitro viability experiments were performed.In vivo work was carried out in athymic nude mice; 2 × 106 CRIPTO overexpressing HCC827 cells were implanted per mouse.EGFR mutant NSCLC patient blood samples were collected before treatment with and EGFR-TKI, during response while on treatment, and at progression while on treatment. ResultsAlthough both membrane bound and secreted CRIPTO forms were able to activate downstream pathways such as SRC, CRIPTO was unable to elicit resistance towards osimertinib in vitro or in vivo. CRIPTO serum levels in mice were higher in larger xenograft tumors. Furthermore, CRIPTO serum levels were higher in patients with progressing lung cancer when compared to their CRIPTO serum levels during EGFR-TKI response. ConclusionsCRIPTO does not cause resistance against third generation EGFR-TKI osimertinib. CRIPTO levels in serum might be a potentially useful biomarker for tumor burden in NSCLC patients.