Sensitive Epidermal Growth Factor Receptor Mutations Research Articles

Abstract 3263: VEGFA mediates traditional EGFR-TKI resistance in non-small cell lung cancer with EGFR exon 20 insertions

Abstract Background: Epidermal growth factor receptor (EGFR) exon 20 insertions (Ex20ins) accounted for 4%-12% of EGFR mutations and showed primary resistance to EGFR tyrosine kinase inhibitors (EGFR-TKIs) which is an urgent issue to be solved. In our previous studies, we found that antiangiogenetic therapy had certain advantages for patients with Ex20ins in the real-world practice. Previous research showed the tumor microenvironment has been associated with resistance to targeted therapy in sensitive mutations. However, the mechanism of resistance of EGFR-TKIs and the advantage of antiangiogenetic therapy in patients with EGFR Ex20ins were still unclear. Methods: In this study, patients with EGFR exon 19 deletion (19del), exon 21 p.L858R (21L858R), and Ex20ins were collected to identify the efficacy of EGFR-TKIs. Stable cell lines expressing were established and used to compare signaling pathway activation. Matrigel angiogenesis assay was conducted in different cell lines. Next, we evaluated the efficacy of various treatments combined with antiangiogenetic agents or not in mouse models. Results: We collected 23 patients with EGFR sensitive mutations and Ex20ins, respectively, and found Ex20ins presented primary resistance to TKIs and poor survival outcomes. Based on the RNA sequence of stable cell lines, it was found that Ex20ins had a higher level of VEGFA expression and enriched in MAPK pathway compared to EGFR 19del and 21L858R. Immunohistochemical studies also revealed that a higher level of VEGFA expression was observed in a cohort of NSCLC patients with Ex20ins mutation compared with 19del or L858R. Matrigel angiogenesis assay has shown consistent result that Ex20ins promoted angiogenesis in vivo. Further experiments in mouse models identified that in the group of Osimertinib, mobocertinib alone, chemotherapy alone, mobocertinib or chemotherapy combination with bevacizumab, Osimertinib achieved the worst efficacy and additional utility of antiangiogenetic agents had a more favorable efficacy. Conclusion: Our study highlights the potential of VEGFA as a mechanism of resistance to EGFR-TKIs and induces immunosuppression microenvironment in NSCLC with Ex20ins. Furthermore, the findings suggested that antiangiogenetic therapy could be a promising therapeutic approach. Keywords: VEGFA, targeted therapy, resistance, EGFR exon 20 insertions, non-small cell lung cancer Citation Format: Yaning Yang, Chengming Liu, Guangjian Yang, Haiyan Xu, Siyu Lei, Yan Wang. VEGFA mediates traditional EGFR-TKI resistance in non-small cell lung cancer with EGFR exon 20 insertions [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 3263.

Abstract 7203: Anti-HDGF antibody attenuates the rise of resistance to EGFR tyrosine kinase inhibitor in NSCLC patient-derived xenograft tumors

Abstract Mutant epidermal growth factor receptor (EGFR), a major oncogenic driver in non-small cell lung cancer (NSCLC), is found in the tumors of 15% (western countries) to 50% (Asian countries) of patients. EGFR-targeted therapy using tyrosine kinase inhibitors (TKIs) is a standard of care for those patients who developed metastatic or recurrent diseases. However, despite having an 80% initial response rate, most patients had partial tumor regression and their disease would progress when acquired resistance emerges. Thus, developing more effective treatment is an unmet need. The clinical response of these patients can be recapitulated in mouse models of patient-derived xenograft (PDX) tumor bearing sensitizing EGFR mutations. In this study, treating established PDX tumors with osimertinib, a third generation EGFR TKI, induced partial tumor regression (50% to 70% size reduction from baseline) followed by progression with a median progression-free survival (PFS) of 26 to 28 days. Interestingly, co-administering an antibody against hepatoma-derived growth factor (HDGF) with osimertinib resulted in enhanced tumor regression (98% to 100% size reduction from baseline) which translated into significantly extended animal survival with a median PFS of 103 or 135 days. Immunohistochemical and western blot examination of tumors collected at different treatment timepoints indicated that AKT/mTOR and MAPK pathways were reactivated after initial suppression in TKI monotherapy arm despite persistent EGFR inhibition. Since AKT/mTOR and MAPK pathways are key survival and proliferative signaling pathways, their reactivation can promote TKI tolerance of tumor cells and the emergence of TKI resistance. However, blocking HDGF attenuated the reactivation of these pathways which could partially explain the enhanced efficacy of osimertinib plus anti-HDGF antibody combination treatment seen in this study. Our results suggest tumor-derived HDGF could play a crucial role in the rise of acquired resistance to osimertinib. Identifying the exact cells and molecular pathways utilized by HDGF to promote tumor cell tolerance to TKI will help us understand how TKI sensitive tumor cells survive EGFR blockade and emerge as resistant cells. Citation Format: Cindy Q. Zhou, Ariel Li, Kaoru Ri, Ahmed Sultan, Hening Ren. Anti-HDGF antibody attenuates the rise of resistance to EGFR tyrosine kinase inhibitor in NSCLC patient-derived xenograft tumors [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 7203.

The efficacy of furmonertinib in untreated advanced NSCLC patients with sensitive EGFR mutations in a real-world setting: a single institutional experience.

Furmonertinib is the standard treatment option in the first-line setting for advanced non-small cell lung cancer (NSCLC) with sensitive epidermal growth factor receptor (EGFR) mutations in China. However, there are limited real-world data available. We conducted a retrospective study at a single center, analyzing a cohort of 73 NSCLC patients who tested positive for EGFR mutations and were treated with furmonertinib as their initial therapy between August 2022 and December 2023. The primary endpoint was progression-free survival (PFS), with secondary endpoints including objective response rate (ORR), overall survival (OS), and safety profile. The median observation period was 9 months (95% confidence interval [CI], 8.0-20.0). The median PFS was 19.5 months (95% CI, 14.6-24.4). OS data were not yet mature. Univariate analysis showed no significant correlation between PFS and factors such as Eastern Cooperative Oncology Group performance status (ECOG PS) score, presence of brain or liver metastases, sex, age, EGFR mutation status, or number of metastatic sites. However, multivariate analysis indicated a potential trend toward extended PFS in patients younger than 65 years (p = 0.053, 95% CI, 0.10-1.02), although the p-value was only marginally significant. The most common adverse events were diarrhea (24%), anemia (36%), and liver injury (32%); however, only four cases experienced severe adverse events. In a real-world setting, furmonertinib appears to be a favorable treatment option for EGFR-mutated patients. The manageable nature of adverse events further supports its use in clinical practice.

A phase II study of atezolizumab with bevacizumab, carboplatin, and paclitaxel for patients with EGFR-mutated NSCLC after TKI treatment failure (NEJ043 study)

IntroductionTreatment options for patients with epidermal growth factor receptor (EGFR)-mutated non-small cell lung cancer (NSCLC) after EGFR-tyrosine kinase inhibitor (TKI) treatment failure are limited. An exploratory analysis of 26 patients in the IMpower150 study indicated that treatment with atezolizumab, bevacizumab, carboplatin, and paclitaxel (ABCP) was effective in patients with EGFR-mutated NSCLC. This phase II study was conducted to assess the efficacy of ABCP in EGFR-mutated NSCLC patients after TKI treatment. MethodsPatients with non-squamous NSCLC harboring sensitizing EGFR mutations were enrolled. ABCP therapy was administered every 3 weeks for four cycles, followed by maintenance therapy with atezolizumab and bevacizumab. The primary endpoint was progression-free survival (PFS) according to extramural review (ER). Key secondary endpoints and preplanned analysis included overall survival (OS), overall response rate (ORR), and differences in the efficacy of ABCP according to prior EGFR-TKI administration, liver metastases, and brain metastases. ResultsSixty patients from 26 centers were enrolled. Median PFS was 7.4 months (95% confidence interval [CI]: 5.7–8.2). The median OS was 23.1 months (95% CI: 13.1-not reached), and the ORR was 55.9%. PFS was significantly shorter in patients who had received osimertinib as a first-line treatment (7.2 months vs. 7.4 months, hazard ratio [HR] 1.932, p = 0.023), those with brain metastases (5.7 months vs. 8 months, HR 1.86, p = 0.032), or those with liver metastases (5.4 months vs. 7.9 months, HR 2.779, p = 0.003). ConclusionsAlthough this study did not meet the primary endpoint, ABCP showed clinically meaningful efficacy in EGFR-mutated NSCLC patients.

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.

Furmonertinib as adjuvant therapy in postoperative EGFR-mutated stage IA2-IIIA non-small cell lung cancer (NSCLC) with high-risk pathological factors.

150 Background: NSCLC patients with high-risk pathological factors such as micropapillary (MP), solid (S), spread through air spaces (STAS), and visceral pleural invasion (VPI) have shown poor prognosis in previous studies. Furmonertinib (AST2818) is a novel, promising oral third-generation epidermal growth factor receptor (EGFR) tyrosine kinase inhibitor (TKI), which has demonstrated efficacy in tumours harbouring sensitive EGFR mutations and T790M resistance mutation. Here, we investigated the efficacy and safety of furmonertinib as adjuvant therapy in postoperative EGFR-mutated NSCLC patients with high-risk pathological factors. Methods: Patients who underwent radical lung cancer surgery with both EGFR mutations and MP/S/STAS/VPI were enrolled and received furmonertinib 80mg daily. The adjuvant therapy time (6-36months) depended on patients’ pathologic stage and physical conditions. The disease-free survival (DFS), safety and tolerability were evaluated. Results: This study retrospectively analyzed 69 patients who were pathologically confirmed adenocarcinoma, EGFR mutation positive (exon 19 deletion/L858R/exon 20ins), stage IA2-IIIA NSCLC. All of them had at least one high-risk pathological factor. There were 44 (63.8%) patients with MP, 14 (20.3%) with S, 10 (14.5%) with STAS and 33 (47.8%) with VPI. All patients were followed at least 13 months, and 24 (34.8%) of them have been followed up for over 21 months, median follow-up time was 18.5 months. By the cut-off date of March 1, 2023, all patients were alive and with no radiographic recurrence, including 3 (4.3%) with exon 20ins. During therapy, 26 (37.7%) patients had treatment-related adverse events (TRAEs) of any grade. The most common TRAEs were rash (12/69, 17.4%), mouth ulcer (6/69, 8.7%), diarrhea (5/69, 7.2%) and transaminase elevation (4/69, 5.8%). Only 2 (2.9%) patients had TRAEs of grade 3 or higher and 1(1.4%) of the two discontinued therapy. Conclusions: This is the first study to demonstrate that furmonertinib has good efficacy and a tolerable safety profile as adjuvant therapy in EGFR-mutated NSCLC patients with high-risk pathological factors who underwent radical lung cancer surgery.[Table: see text]

Clinical Validation of the Unparalleled Sensitivity of the Novel Allele-Discriminating Priming System Technology-Based EGFR Mutation Assay in Patients with Operable Non-Small Cell Lung Cancer.

Recently, we developed allele-discriminating priming system (ADPS) technology. This method increases the sensitivity of conventional quantitative polymerase chain reaction up to 100 folds, with limit of detection, 0.01%, with reinforced specificity. This prospective study aimed to develop and validate the accuracy of ADPS epidermal growth factor receptor (EGFR) Mutation Test Kit using clinical specimens. In total 189 formalin-fixed paraffin-embedded tumor tissues resected from patients with non-small cell lung cancer were used to perform a comparative evaluation of the ADPS EGFR Mutation Test Kit versus the cobas EGFR Mutation Test v2, which is the current gold standard. When the two methods had inconsistent results, next-generation sequencing-based CancerSCAN was utilized as a referee. The overall agreement of the two methods was 97.4% (93.9%-99.1%); the positive percent agreement, 95.0% (88.7%-98.4%); and the negative percent agreement, 100.0% (95.9%-100.0%). EGFR mutations were detected at a frequency of 50.3% using the ADPS EGFR Mutation Test Kit and 52.9% using the cobas EGFR Mutation Test v2. There were 10 discrepant mutation calls between the two methods. CancerSCAN reproduced eight ADPS results. In two cases, mutant allele fraction was ultra-low at 0.02% and 0.06%, which are significantly below the limit of detection of the cobas assay and CancerSCAN. Based on the EGFR genotyping by ADPS, the treatment options could be switched in five patients. The highly sensitive and specific ADPS EGFR Mutation Test Kit would be useful in detecting the patients who have lung cancer with EGFR mutation, and can benefit from the EGFR targeted therapy.

A phase 1 study to assess BDTX-1535, an oral EGFR inhibitor, in patients with glioblastoma or non–small-cell lung cancer.

TPS9156 Background: The epidermal growth factor receptor (EGFR) is a potent oncogene commonly altered in many cancers, including glioblastoma (GBM) and non-small cell lung cancer (NSCLC). EGFR tyrosine kinase activity driven by common EGFR mutations can be inhibited by small molecules, however, resistance to available agents may be driven by mutations in the EGFR active kinase site or other regions. BDTX-1535 is an orally available, highly potent, selective, irreversible inhibitor of EGFR mutations, including extracellular variants and amplifications commonly expressed in GBM and inhibits the common and uncommon EGFR mutations found in NSCLC, including the C797S mutation acquired following 3rd generation EGFR inhibitor therapy. Preclinical data demonstrated the ability of BDTX-1535 to cross the blood-brain barrier and produce sustained inhibition of EGFR signaling. Preclinical studies suggest that BDTX-1535 has the potential to be clinically active in suppressing tumor growth in patients with GBM and NSCLC with or without CNS metastases, including a potential survival benefit. Methods: BDTX-1535-101 (NCT05256290) is Phase 1, open-label, multicenter study to assess the safety, tolerability, PK, CNS activity, and preliminary antitumor activity of BDTX-1535 in recurrent GBM (rGBM) or locally advanced or metastatic NSCLC with or without CNS disease. The Monotherapy Dose Escalation portion will evaluate BDTX-1535 in patients with either rGBM expressing EGFR alterations or locally advanced/metastatic NSCLC harboring sensitizing EGFR mutations with or without CNS disease. Patients with rGBM must have previously received available standard therapy of surgical resection followed by chemoradiotherapy and/or temozolomide (TMZ). Eligible NSCLC patients must have EGFR mutated NSCLC that has progressed following standard of care EGFR inhibitor therapy. Once a provisional recommended Phase 2 dose (RP2D) has been established, BDTX-1535 monotherapy will be explored in the following Dose Expansion cohorts to further evaluate safety, PK, and preliminary assessment of efficacy: 1) rGBM with confirmed EGFR alterations, 2) NSCLC with uncommon EGFR mutations following EGFR inhibitor therapy; 3) NSCLC with acquired EGFR resistance mutation following a 3rd generation EGFR inhibitor in 1L setting. NSCLC patients may enroll with or without CNS metastases and must not be known to express excluded resistance mutations such as EGFR T790M or MET. BDTX-1535 will also be studied in combination with TMZ to assess safety, tolerability, and a recommended combination dose for the treatment of patients with rGBM harboring EGFR mutations or variants. Enrollment was initiated in 2022 and dose escalation is ongoing. Dose Expansion cohorts are expected to open in 2023. For additional information, please contact BDTX_1535_101_Study@bdtx.com . Clinical trial information: NCT05256290 .

Retreatment with EGFR inhibitor in non-small cell lung cancer patients previously exposed to EGFR-TKI: A systematic review and meta-analysis.

e21159 Background: Epidermal growth factor receptor (EGFR) tyrosine kinase inhibitors (TKI) are the standard therapy for EGFR-mutated non-small cell lung cancer (NSCLC) patients. Unfortunately, patients eventually develop resistance to EGFR-TKI and disease progression. Re-exposure after a drug-free interval may be an alternative to overcome tumor resistance. We performed a systematic review and meta-analysis to assess EGFR-TKI retreatment’s efficacy in advanced NSCLC. Methods: We systematically searched PubMed, Embase, and Cochrane databases for clinical trials and observational cohort studies evaluating EGFR-TKI retreatment in advanced NSCLC patients. We aimed to assess the objective response rate (ORR), disease control rate (DCR), and survival outcomes. Subgroup analyses were performed according to the type of EGFRmutation and the TKI drug used in retreatment. We further stratified studies to assess the efficacy of rechallenging with the same drug used initially or a different one. Heterogeneity was assessed using the Cochran Q test, and I2 statistics and random effects models were fitted. Results: We included 16 studies (7 prospective clinical trials, and 9 retrospective cohorts) with 806 patients. Most of them had adenocarcinoma (70.8%), were females (58.1%), and were non-smokers (74.5%). The most frequently TKI given as the initial treatment was gefitinib (58.1%), whereas in the rechallenge it was erlotinib (36.6%) followed by gefitinib (31.6%). In a pooled analysis of patients who were retreated with TKI, the median PFS was 4.1 months (95%CI 3.0 - 4.4), and OS was 12.6 months (95%CI 10.2 - 12.6). ORR was 16% (95%CI 10 - 22%) and DCR was documented in 63% (95%CI 0.54 - 0.72%). Patients harboring a sensitive EGFR mutation had a significantly higher DCR, compared to patients with EGFRT790M mutation, and those with unknown mutational status, (DCR: 70%, 62%, and 48%, respectively, p = 0.02). Patients rechallenged with gefitinib, erlotinib, or afatinib had a similar DCR of 60%, while patients re-exposed to osimertinib had a greater DCR of 70% (95%CI 59 - 80%), (p < 0.01). Regarding ORR, no significant difference was observed amongst the groups defined by the type of EGFR mutation (p = 0.74) or type of TKI used (p = 0.05). Rechallenge using the same versus a different TKI resulted in similar ORR and DCR. In a subgroup analysis of 102 patients who had disease control with the first TKI, 62% (95%CI 45 – 79%) achieved disease control with TKI rechallenge. Conclusions: Our meta-analysis suggests that a subgroup of advanced EGFR-mutated NSCLC patients who failed TKI treatment benefit from rechallenge with an EGFR-TKI after a TKI-free interval. Re-exposure with either the same or a different TKI was shown to be equally effective. Patients treated with osimertinib and those with EGFR-sensitive mutations have better responses to the treatment.

The Glasgow Prognostic Score Predicts Survival in Patients with Advanced Non-Small Cell Lung Cancer Harboring Sensitive Epidermal Growth Factor Receptor Mutations Who Are Treated with Epidermal Growth Factor Receptor-Tyrosine Kinase Inhibitors

Introduction: Epidermal growth factor receptor (EGFR)-tyrosine kinase inhibitors (TKIs) are the standard first-line treatment for advanced non-small cell lung cancer (NSCLC) with sensitive EGFR mutations. The Glasgow prognostic score (GPS) is an inflammation-assessing score based on C-reactive protein and albumin concentrations. Information regarding the association between the GPS and EGFR-TKI treatment effectiveness is limited; hence, we investigated whether the GPS can predict the response of NSCLC to EGFR-TKIs. Methods: We evaluated 340 patients with NSCLC harboring sensitive EGFR mutations who received EGFR-TKI monotherapy between March 2009 and July 2021. The Kaplan-Meier method and Cox proportional hazards models were used to assess progression-free survival (PFS) and overall survival (OS). Results: After a median follow-up of 26.6 months, patients with a GPS of 0, 1, and 2 had PFS of 15.7, 10.0, and 6.3 months, respectively, and OS of 40.1, 25.8, and 14.4 months, respectively; patients with a GPS of 0 had significantly better PFS and OS than those with a GPS of 1 (p = 0.03, p = 0.001, respectively) or 2 (p < 0.001, p < 0.001, respectively). Multivariate analysis identified poor performance status, stage 4 at diagnosis, type of EGFR-TKI (gefitinib/erlotinib vs. afatinib), and GPS = 2 as predictors of a short PFS. Meanwhile, poor performance status, gefitinib/erlotinib administration, and GPS = 2 were predictors of a short OS. Conclusion: The GPS predicted the survival of NSCLC patients harboring sensitive EGFR mutations who were undergoing EGFR-TKI treatment. The GPS might be ideal for routine use in clinical practice, given that it is an easily calculated parameter.

Abstract CT127: A phase 1 study to assess BDTX-1535, an oral EGFR inhibitor, in patients with glioblastoma or non-small cell lung cancer

Abstract Background: The epidermal growth factor receptor (EGFR) is a potent oncogene commonly altered in many cancers, including glioblastoma (GBM) and non-small cell lung cancer (NSCLC). EGFR tyrosine kinase activity driven by common EGFR mutations can be inhibited by small molecules, however, resistance to available agents may be driven by mutations in the EGFR active kinase site or other regions. BDTX-1535 is an orally available, highly potent, selective, irreversible inhibitor of EGFR mutations, including extracellular variants and amplifications commonly expressed in GBM and inhibits the uncommon EGFR mutations found in NSCLC, including the C797S mutation acquired following 3rd generation EGFR inhibitor therapy. Preclinical data demonstrated the ability of BDTX-1535 to cross the blood-brain barrier and produce sustained inhibition of EGFR signaling. Preclinical studies suggest that BDTX-1535 has potential to be clinically active in suppressing tumor growth in patients with GBM and NSCLC with or without CNS metastases, including a potential survival benefit. Methods: BDTX-1535-101 (NCT05256290) is Phase 1, open-label, multicenter study to assess the safety, tolerability, PK, CNS penetrance, and preliminary antitumor activity of BDTX-1535 in recurrent GBM (rGBM) or locally advanced or metastatic NSCLC with or without CNS disease. The Monotherapy Dose Escalation portion will evaluate BDTX-1535 in patients with either rGBM expressing EGFR alterations or locally advanced/metastatic NSCLC harboring sensitizing EGFR mutations with or without CNS disease. Patients with rGBM must have previously received available standard therapy of surgical resection followed by chemoradiotherapy and/or temozolomide (TMZ). Eligible NSCLC patients must have EGFR mutated NSCLC that has progressed following standard of care EGFR inhibitor therapy. Once a provisional recommended Phase 2 dose (RP2D) has been established, BDTX-1535 monotherapy will be explored in the following Dose Expansion cohorts to further evaluate safety, PK, and preliminary assessment of efficacy: 1) rGBM with confirmed EGFR alterations, 2) NSCLC with uncommon EGFR mutations following EGFR inhibitor therapy; 3) NSCLC with acquired EGFR resistance mutation following a 3rd generation EGFR inhibitor in 1L setting. NSCLC patients may enroll with or without CNS metastases and must not be known to express excluded resistance mutations such as EGFR T790M or MET. BDTX-1535 will also be studied in combination with TMZ to assess safety, tolerability, and a recommended combination dose for the treatment of patients with rGBM harboring EGFR mutations or variants. Enrollment was initiated in 2022 and dose escalation is ongoing. Dose Expansion cohorts are expected to open in 2023. For additional information, please contact BDTX_1535_101_Study@bdtx.com Citation Format: Melissa Johnson, Jason Henry, Alex Spira, James Battiste, Iyad Alnahhas, Manmeet Ahluwalia, Minal Barve, Jeffrey Edenfield, DoHyun Nam, Sudharshan Eathiraj, Julio Hajdenberg, Sergey Yurasov, Helena Yu, Patrick Wen. A phase 1 study to assess BDTX-1535, an oral EGFR inhibitor, in patients with glioblastoma or non-small cell lung cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 2 (Clinical Trials and Late-Breaking Research); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(8_Suppl):Abstract nr CT127.

Osimertinib Resistance: Molecular Mechanisms and Emerging Treatment Options.

The development of tyrosine kinase inhibitors (TKIs) targeting the mutant epidermal growth factor receptor (EGFR) protein initiated the success story of targeted therapies in non-small-cell lung cancer (NSCLC). Osimertinib, a third-generation EGFR-TKI, is currently indicated as first-line therapy in patients with NSCLC with sensitizing EGFR mutations, as second-line therapy in patients who present the resistance-associated mutation T790M after treatment with previous EGFR-TKIs, and as adjuvant therapy for patients with early stage resected NSCLC, harboring EGFR mutations. Despite durable responses in patients with advanced NSCLC, resistance to osimertinib, similar to other targeted therapies, inevitably develops. Understanding the mechanisms of resistance, including both EGFR-dependent and -independent molecular pathways, as well as their therapeutic potential, represents an unmet need in thoracic oncology. Interestingly, differential resistance mechanisms develop when osimertinib is administered in a first-line versus second-line setting, indicating the importance of selection pressure and clonal evolution of tumor cells. Standard therapeutic approaches after progression to osimertinib include other targeted therapies, when a targetable genetic alteration is detected, and cytotoxic chemotherapy with or without antiangiogenic and immunotherapeutic agents. Deciphering the when and how to use immunotherapeutic agents in EGFR-positive NSCLC is a current challenge in clinical lung cancer research. Emerging treatment options after progression to osimertinib involve combinations of different therapeutic approaches and novel EGFR-TKI inhibitors. Research should also be focused on the standardization of liquid biopsies in order to facilitate the monitoring of molecular alterations after progression to osimertinib.

Rationale and protocol design of a phase II study of first-line osimertinib treatment for patients with poor performance status and EGFR mutation-positive non-small cell lung cancer (OPEN/TORG2040)

BackgroundCancer chemotherapy indications for patients with poor performance status and advanced lung cancer are limited. Molecular targeted drugs, including epidermal growth factor receptor (EGFR)-tyrosine kinase inhibitors, can be used in patients with poor performance status owing to their high efficacy and safety. The third-generation EGFR-tyrosine kinase inhibitor osimertinib has demonstrated effectiveness in the initial treatment of advanced EGFR mutation-positive non-small cell lung cancer in patients with good performance status; however, no evidence exists of the drug’s effectiveness in patients with poor performance status in a prospective study. We designed a study that aims to investigate the efficacy and safety of first-line osimertinib treatment in patients with advanced non-small cell lung cancer harboring sensitive EGFR mutations and with poor performance status.MethodsThe OPEN/TORG2040 study is a multicenter, single-arm, phase II trial for patients with unresectable, advanced EGFR mutation-positive non-small cell lung cancer with a poor performance status (≥ 2). Eligible patients will receive osimertinib until disease progression or unacceptable toxicity. The primary endpoint is the objective response rate of the first-line osimertinib treatment. Considering a threshold value of 45%, expected value of 70% for objective response rate, one-sided significance level of 5%, statistical power of 80%, and ineligible patients, the sample size was set to 30. The secondary endpoints are disease control rate, performance status improvement rate, and safety and patient-reported outcomes using the European Organization for Research and Treatment of Cancer Quality of Life Questionnaire-Core Quality of Life Questionnaire and Lung Cancer 13. Time to treatment failure, progression-free survival, and overall survival will also be assessed.DiscussionOur study can determine the clinical benefits of osimertinib treatment in patients with poor performance status, since the clinical outcomes of patients with EGFR mutation-positive non-small cell lung cancer with poor performance status treated with this drug as a first-line treatment have not been sufficiently evaluated.Trial registrationJapan Registry of Clinical Trials: jRCTs041200100 (registration date: February 12, 2021).

Efficacy Differences of First-line EGFR-TKIs Alone vs in Combination with Chemotherapy in Advanced Lung Adenocarcinoma Patients with Sensitive EGFR Mutation and Concomitant Non-EGFR Genetic Alterations.

Background and objectiveEpidermal growth factor receptor (EGFR) mutations are often associated with non-EGFR genetic alterations, which may be a reason for the poor efficacy of EGFR tyrosine kinase inhibitors (TKIs). Here we conducted this study to explore whether EGFR-TKIs combined with chemotherapy would benefit advanced lung adenocarcinoma patients with both sensitive EGFR mutation and concomitant non-EGFR genetic alterations.Materials and methodsCases of advanced lung adenocarcinoma with EGFR mutation combined with concomitant non-EGFR genetic alterations were retrospectively collected. And the patients were required to receive first-line EGFR-TKIs and chemotherapy combination or EGFR-TKIs monotherapy. Demographic, clinical and pathological data were collected, and the electronic imaging data were retrieved to evaluate the efficacy and time of disease progression. Survival data were obtained through face-to-face or telephone follow-up. The differences between the two groups in objective response rate (ORR), disease control rate (DCR), progression-free survival (PFS) and overall survival (OS) were investigated.Results107 patients were included, including 63 cases in the combination group and 44 cases in the monotherapy group. The ORR were 78% and 50% (P=0.003), and DCR were 97% and 77% (P=0.002), respectively. At a median follow-up of 13.7 mon, a PFS event occurred in 38.1% and 81.8% of patients in the two groups, with median PFS of 18.8 mon and 5.3 mon, respectively (P < 0.000, 1). Median OS was unreached in the combination group, and 27.8 mon in the monotherapy group (P=0.31). According to the Cox multivariate regression analysis, combination therapy was an independent prognostic factor of PFS.ConclusionIn patients with EGFR-mutant advanced lung adenocarcinoma with concomitant non-EGFR genetic alterations, combination of TKIs and chemotherapy was significantly superior to EGFR-TKIs monotherapy, which should be the preferred treatment option.

948TiP Efficacy and safety of almonertinib in the adjuvant treatment of resectable stage I non-small cell lung cancer (NSCLC) with epidermal growth factor receptor (EGFR)-sensitizing mutations in solid and/or micropapillary components

Pathological subtypes are prognostic indicators independent of TNM stage, and patients with micropapillary and solid components have poorer prognosis. Previous studies have found that the presence of a micropapillary component was significantly associated with worse recurrence-free survival in patients with stage I lung adenocarcinoma, even the components are less than 5%, and postoperative adjuvant chemotherapy can still bring benefit to those patients even with stage IA. Third-generation EGFR-TKI have recently shown striking benefit for postoperative adjuvant therapy in patients with EGFR-mutated NSCLC. At present, there is no systematic study on the efficacy and safety of third-generation EGFR-TKI in stage I NSCLC patients with high-risk recurrence factors, such as solid and micropapillarycomponents. The third-generation EGFR-TKI, aumolertinib(HS-10296), showed promising efficacy in advanced NSCLC patients with sensitive EGFR mutation. This is the first study to explore the efficacy and safety of aumolertinib as adjuvant therapy in patients with EGFR mutant stage I NSCLC with solid and/or micropapillary component. Approximately 52 stage I EGFR-mutated NSCLC patients with solid and/or micropapillary components ≥10% will be enrolled in this multicenter single-arm study. After radical lung cancer surgery, they will receive oral almonertinib 110 mg/d as adjuvant therapy for 3 years. The primary endpoint is 2-year disease free survival (DFS) rates, and secondary endpoints included the 3-, 4-, and 5-year DFS rates, 5-year overall survival rates, safety and quality of life, Circulating tumor DNA will also be monitored during the study. Recruitment of this study is ongoing, and the first patient had been enrolled in January 2022. The author.

Study Design and Rationale for the PACE-LUNG Trial: A Multicenter, Single-Arm, Phase II Clinical Trial Evaluating the Efficacy of Additional Chemotherapy for Patients with EGFRm NSCLC with the Continued Presence of Plasma ctDNA EGFRm at Week 3 After Start of Osimertinib First-Line Treatment

BackgroundTyrosine kinase inhibitors (TKI) targeting the epidermal growth factor receptor (EGFR) like the third-generation TKI osimertinib have substantially improved the treatment of patients with advanced non-small cell lung cancer (NSCLC) harboring sensitizing EGFR mutations. However, there is a subset of patients that do not benefit from these therapies in terms of response rate or progression-free-survival (PFS). It has been shown that persistence of EGFR mutations in circulating tumor DNA (ctDNA) at weeks 3 and 6 after start of osimertinib predicts shorter PFS. These patients may benefit from additional chemotherapy. While combination therapies with older TKI have been demonstrated effective in improving outcome, they are associated with a significant increase in toxicity. Patients and MethodsPACE-LUNG is a multicenter, single-arm, investigator initiated, phase II trial conducted with the German national Network Genomic Medicine (nNGM). Patients with stage IIIB or IV NSCLC and exon 19 deletion or p.L858R EGFR mutation not amenable to curative treatment with persisting ctDNA after 3 to 4 weeks of first-line osimertinib monotherapy will receive additional chemotherapy (4 cycles of either cisplatin/pemetrexed or carboplatin/pemetrexed). Afterwards, osimertinib will be continued as standard of care until disease progression or intolerable toxicity. The primary endpoint is PFS. Secondary endpoints include overall survival, response rate, safety, and quality of life. Concomitant translational research will be performed to identify patterns of mutational evolution in ctDNA upon disease progression or ctDNA persistence. Enrollment started in December 2021. DiscussionThe PACE-LUNG trial is designed to evaluate the efficacy and safety of a biomarker-driven strategy for therapy escalation in patients at high risk for early treatment failure. This approach aims not only to improve treatment outcomes, but also to limit the anticipated additional toxicity to high-risk patients. Trial registration number: 2019-004757-88 (EudraCT)

Pharmacokinetic boosting of osimertinib with cobicistat in patients with non-small cell lung cancer: The OSIBOOST trial

IntroductionExposure to osimertinib, a third generation epidermal growth factor receptor (EGFR) tyrosine kinase inhibitor (TKI) for treatment of non-small cell lung cancer (NSCLC) and a sensitizing EGFR mutation, can be substantially below average. We evaluated whether plasma levels could be boosted by co-administration of cobicistat, a strong Cytochrome P450 3A-inhibitor. MethodsThis was a pharmacokinetic, proof-of-concept clinical trial (the OSIBOOST trial, NCT03858491). NSCLC-patients with osimertinib were eligible if their steady state osimertinib plasma trough concentration was low (≤195 ng/mL). On day 1, the area under the plasma curve (AUC0-24,ss) of osimertinib and its metabolite (AZ5104) was calculated using a limited sampling strategy (four samples). Cobicistat co-treatment (150 mg, once daily) was started on day 2. Between day 22–26, a second AUC was determined. Cobicistat dose could be escalated if the osimertinib trough concentration was still ≤ 195 ng/mL, in the absence of toxicity. Primary endpoint was the increase in osimertinib exposure, secondary endpoint was toxicity. Cobicistat could be continued during the expanded access phase, with follow-up (2–4 months) of the boosting effect. ResultsThe mean baseline osimertinib trough concentration for the eleven enrolled patients was 154 ng/mL. In all patients, cobicistat addition led to an increase in osimertinib exposure. Mean increase in total AUC0-24ss (AUC osimertinib + AUC AZ5104) was 60%, (range 19%–192%). The boosting effect was consistent over time. No grade ≥ 2 toxicity was observed. ConclusionPharmacokinetic boosting of osimertinib with cobicistat in patients with NSCLC is feasible without increasing toxicity, although the degree of boosting is variable.

Prognostic factors in completely resected lymph-node-negative pulmonary adenocarcinoma.

BackgroundLymph node involvement is one of the important prognostic factors for early-stage lung cancer. However, in lymph node-negative (N0) lung cancer the recurrent rate may be as high as 30%. We aimed to study potential prognostic factors including clinicopathological factors and epidermal growth factor receptor (EGFR) mutation status in this lung cancer population.MethodsWe retrospectively reviewed the medical records and pathological examinations of patients with completely resected N0 pulmonary adenocarcinoma treated in our institute between 2009 and 2016. We used Cobas® test to determine EGFR mutation status. Recurrence-free survival (RFS) was analyzed by univariable and multivariable Cox regression analyses.ResultsWe recruited 220 patients with median duration of follow up 5 years. Majority of these patients were in stage I (80%) and did not receive adjuvant therapy (86%). There were 53% with EGFR mutations which comprised of exon 19 deletion 51% and L858R 43%. Recurrence occurred in 64 out of 220 patients (29%). The median time to recurrence was 2.1 years. Statistically significant prognostic factors in both univariate and multivariate analyses included tumor size ≥4 centimeter (cm) (HR: 1.94; 95% CI: 1.03–3.67), visceral pleural invasion (HR: 2.53; 95% CI: 1.34–4.79), tumor necrosis (HR: 2.45; 95% CI: 1.13–5.31) and bronchial resection margin <2 cm (HR: 1.96; 95% CI: 1.10–3.51). However, presence of sensitizing EGFR mutation was not found to be a significant prognostic factor (HR: 1.20; 95% CI: 0.66–2.18; P=0.56).ConclusionsIn N0 surgically resected lung adenocarcinoma, there were significant pathological prognostic factors including tumor 4 cm or more, visceral pleural invasion, tumor necrosis and bronchial resection margin less than 2 cm. Mutation of EGFR is not a significant prognostic factor to determine the risk of recurrence in this population and their risks shall be determined by the other poor prognostic factors.

PD-L1 strong expressions affect the clinical outcomes of osimertinib in treatment naïve advanced EGFR-mutant non-small cell lung cancer patients

The impact of strong Programmed Death-ligand 1 (PD-L1) expression on the clinical outcomes of osimertinib in treatment naïve advanced Epidermal Growth Factor Receptor (EGFR)-mutant Non-small Cell Lung Cancer (NSCLC) patients remains uncertain. We enrolled advanced NSCLC patients who harbored sensitizing EGFR mutation and were treated first-line with osimertinib between 2017 and 2021. The PD-L1 expression level was also tested. A total of 85 patients were included. The objective response rate to osimertinib was 78.9%, with the disease control rate being 90.8%. Median Progression-free Survival (PFS) was 22.1 months, while median Overall Survival (OS) was not reached (NR). Patients with the exon 19 deletion experienced better PFS than those with the exon 21 L858R mutation (NR vs 12.4 months, aHR 0.24 (95% CI, 0.10 to 0.57); p = 0.001). Seventy-one of these 85 patients had reported on their PD-L1 expression. Patients with a PD-L1 < 50% experienced longer PFS than patients with a PD-L1 ≧50% (26.5 vs 9.7 months, aHR 0.19 (95% CI, 0.06 to 0.67); p = 0.009). Additionally, patients with a PD-L1 < 50% experienced better OS than those with a PD-L1 ≧50% (NR vs 25.4 months, aHR 0.09 (95% CI, 0.01 to 0.70); p = 0.021). Strong expressions of PD-L1 in treatment naïve advanced EGFR-mutant NSCLC patients were associated with poor prognoses in those undergoing treatment with osimertinib as first-line therapy.

86P Aumolertinib as adjuvant therapy in postoperative EGFR-mutated non-small cell lung cancer

Aumolertinib (HS-10296) is a novel, promising oral third-generation Epidermal Growth Factor Receptor (EGFR) tyrosine kinase inhibitor (TKI), which has demonstrated efficacy in tumours harbouring sensitive EGFR mutations and T790M resistance mutation. Aumolertinib has also been shown to have efficacy in CNS metastasis. However, the efficacy and safety of aumolertinib as adjuvant therapy in postoperative patients remains unknown.