The impact of EGFR T790M mutation status following the development of Osimertinib resistance on the efficacy of Osimertinib in non-small cell lung cancer: A meta-analysis

BACKGROUND

Previous studies have suggested that loss of the EGFR T790M gene mutation may contribute to the development of resistance to Osimertinib in non-small cell lung cancer (NSCLC).

AIMS

This study aims to assess the relationship between the clinical effectiveness of Osimertinib in NSCLC patients and the T790M mutation status following resistance to Osimertinib and examine differences between plasma and tissue tests and between Asian and non-Asian groups.

METHODS

The PubMed, Web of Science, Cochrane, and EMBASE databases were comprehensively searched for studies on the association between T790M mutation status and the efficacy of Osimertinib between January 2014 and November 2023. Meta-analysis was carried out using Review Manager 5.4 software.

RESULTS

After evaluating 2727 articles, a total of 14 studies were included in the final analysis. Positive correlations between EGFR T790M mutation status after Osimertinib resistance and longer PFS (HR: 0.44, 95% CI: 0.30-0.66), longer OS (HR: 0.3, 95% CI: 0.10-0.86), longer TTD (HR: 0.69, 95% CI: 0.45-1.07), and improved clinical outcomes including PFS and TTD subgroups (HR: 0.58, 95% CI: 0.47-0.73) were observed. Subgroup analysis revealed that, compared with the blood tests, the results of the T790M mutation tests by the tissue are more significant (HR: 0.24, 95% CI: 0.11-0.52 for tissue tests; HR: 0.47, 95% CI: 0.22-1.00 for plasma tests), and the PFS of Osimertinib were similar for Asian and non-Asian patients (HR: 0.46, 95% CI: 0.31-0.68 for Asians; HR: 0.12, 95% CI: 0.01-1.27 for non-Asians).

CONCLUSIONS

Persistence of the T790M gene mutation after the development of Osimertinib resistance is associated with higher therapeutic benefits of Osimertinib in NSCLC patients. The results of tissue detection are more significant than those of plasma detection.

Next-generation sequencing-based detection in a breast MMPMN patient with EGFR T790M mutation: a rare case report and literature review

Multiple primary malignant neoplasms (MPMNs) are difficult to identify from the metastasis or recurrence of malignant tumors. Additionally, the genetic mutations in each primary tumor vary from each other; therefore, it is critical to explore potential abnormal genes. Next-generation sequencing (NGS) technology has emerged as a reliable approach for detecting mutated genes in primary tumors and can provide several targeted therapeutic options for patients with MPMNs. Here, we report a case of metachronous multiple primary malignant neoplasm (MMPMN) patient with primary ovarian and breast cancer. Targeted NGS genetic profiling revealed a rare EGFR T790M mutation in this patient's primary breast tumor tissue, which has only been reported previously in breast cancer (BC). Based on the NGS results, osimertinib was recommended for this patient. Although this patient did not receive osimertinib because of gastrointestinal hemorrhage, this case highlights the significance of NGS technology in the diagnosis and treatment of MPMNs.

Central nervous system efficacy of rezivertinib (BPI-7711) in advanced NSCLC patients with EGFR T790M mutation: A pooled analysis of two clinical studies

BACKGROUND

Rezivertinib (BPI-7711) is a novel third-generation epidermal growth factor receptor (EGFR) tyrosine kinase inhibitor (TKI) which revealed the systematic and central nervous system (CNS) antitumor activities for EGFR T790M-mutated advanced NSCLC in previous clinical studies and is further analyzed here.

METHODS

Eligible patients from the previous phase I and phase IIb studies of rezivertinib were included for pooled analysis. Post-progressive patients who received a prescribed dosage (≥180 mg) of rezivertinib orally once daily were included in full analysis set (FAS), while those with stable, asymptomatic CNS lesions, including measurable and non-measurable ones at baseline were included in CNS full analysis set (cFAS). Patients with measurable CNS lesions were included in CNS evaluable for response set (cEFR). BICR-assessed CNS objective response rate (CNS-ORR), CNS disease control rate (CNS-DCR), CNS duration of response (CNS-DoR), CNS progression-free survival (CNS-PFS), and CNS depth of response (CNS-DepOR) were evaluated.

RESULTS

355 patients were included in FAS, among whom 150 and 45 patients were included in cFAS and cEFR. This pooled analysis showed the CNS-ORR was 32.0% (48/150; 95% CI: 24.6-40.1%) and the CNS-DCR was 42.0% (63/150; 95% CI: 34.0-50.3%) in cFAS, while that in cEFR were 68.9% (31/45; 95% CI: 53.4-81.8%) and 100% (45/45; 95% CI: 92.1-100.0%). In cEFR, the median CNS-DepOR and the mean of CNS-DepOR were -52.0% (range: -100.0 to 16.1%) and -46.8% (95% CI: -55.5 to -38.1%). In cFAS, the median CNS-DoR and CNS-PFS were 13.8 (95% CI: 9.6-not calculable [NC]) and 16.5 (95% CI: 13.7-NC) months.

CONCLUSIONS

Rezivertinib demonstrated encouraging clinical CNS efficacy among advanced NSCLC patients with EGFR T790M mutation and CNS metastases.

Favorable survival outcomes in epidermal growth factor receptor (EGFR)-mutant non-small cell lung cancer sequentially treated with a tyrosine kinase inhibitor and osimertinib in a real-world setting

PURPOSE

EGFR tyrosine kinase inhibitor (TKI) therapy in EGFR-mutated lung cancer is limited by acquired resistance. In half of the patients treated with first/second-generation (1st/2nd gen) TKI, resistance is associated with EGFR p.T790M mutation. Sequential treatment with osimertinib is highly active in such patients. Currently, there is no approved targeted second-line option for patients receiving first-line osimertinib, which thus may not be the best choice for all patients. The present study aimed to evaluate the feasibility and efficacy of a sequential TKI treatment with 1st/2nd gen TKI, followed by osimertinib in a real-world setting.

METHODS

Patients with EGFR-mutated lung cancer treated at two major comprehensive cancer centers were retrospectively analyzed by the Kaplan-Meier method and log rank test.

RESULTS

A cohort of 150 patients, of which 133 received first-line treatment with a first/second gen EGFR TKI, and 17 received first-line osimertinib, was included. Median age was 63.9 years, 55% had ECOG performance score of ≥ 1. First-line osimertinib was associated with prolonged progression-free survival (P = 0.038). Since the approval of osimertinib (February 2016), 91 patients were under treatment with a 1st/2nd gen TKI. Median overall survival (OS) of this cohort was 39.3 months. At data cutoff, 87% had progressed. Of those, 92% underwent new biomarker analyses, revealing EGFR p.T790M in 51%. Overall, 91% of progressing patients received second-line therapy, which was osimertinib in 46%. Median OS with sequenced osimertinib was 50 months. Median OS of patients with p.T790M-negative progression was 23.4 months.

CONCLUSION

Real-world survival outcomes of patients with EGFR-mutated lung cancer may be superior with a sequenced TKI strategy. Predictors of p.T790M-associated resistance are needed to personalize first-line treatment decisions.

Efficacy and Safety of Rezivertinib (BPI-7711) in Patients With Locally Advanced or Metastatic/Recurrent EGFR T790M-Mutated NSCLC: A Phase 2b Study

INTRODUCTION

Rezivertinib (BPI-7711) is a novel third-generation EGFR tyrosine kinase inhibitor (TKI) targeting both EGFR-sensitizing mutations and EGFR T790M mutation. This study aimed to evaluate the efficacy and safety of rezivertinib in patients with locally advanced or metastatic/recurrent EGFR T790M-mutated NSCLC.

METHODS

Patients with locally advanced or metastatic/recurrent NSCLC with confirmed EGFR T790M mutation who progressed after first-/second-generation EGFR TKI therapy or primary EGFR T790M mutation were enrolled. Patients received rezivertinib at 180 mg orally once daily until disease progression, unacceptable toxicity, or withdrawal of consent. The primary end point was objective response rate (ORR) assessed by blinded independent central review per Response Evaluation Criteria in Solid Tumors version 1.1. Secondary end points included disease control rate (DCR), duration of response, progression-free survival (PFS), overall survival, and safety. This study is registered with Clinical Trials.gov (NCT03812809).

RESULTS

A total of 226 patients were enrolled from July 5, 2019, to January 22, 2020. By the data cutoff date on January 24, 2022, the median duration of follow-up was 23.3 months (95% confidence interval [CI]: 22.8-24.0). The ORR by blinded independent central review was 64.6% (95% CI: 58.0%-70.8%), and DCR was 89.8% (95% CI: 85.1%-93.4%). The median duration of response was 12.5 months (95% CI: 10.0-13.9), and median PFS was 12.2 months (95% CI: 9.6-13.9). The median overall survival was 23.9 months (95% CI: 20.0-not calculated [NC]). Among 91 (40.3%) patients with central nervous system (CNS) metastases, the median CNS PFS was 16.6 months (95% CI: 11.1-NC). In 29 patients with more than or equal to one brain target lesion at baseline, the CNS ORR and CNS DCR were 69.0% (95% CI: 49.2%-84.7%) and 100% (95% CI: 88.1%-100%), respectively. Time to progression of CNS was 16.5 months (95% CI: 9.7-NC). Of 226 patients, 188 (83.2%) had at least one treatment-related adverse event, whereas grade more than or equal to 3 occurred in 45 (19.9%) patients. No interstitial lung disease was reported.

CONCLUSIONS

Rezivertinib was found to have promising efficacy and favorable safety profile for patients with locally advanced or metastatic/recurrent NSCLC with EGFR T790M mutation.

Spotlight on Furmonertinib (Alflutinib, AST2818). The Swiss Army Knife (del19, L858R, T790M, Exon 20 Insertions, "uncommon-G719X, S768I, L861Q") Among the Third-Generation EGFR TKIs?

Osimertinib, a third-generation (3G) epidermal growth factor receptor (EGFR) tyrosine kinase inhibitor (TKI) is now considered the standard of care for the first-line (1L) treatment of advanced EGFR+ NSCLC due to statistically significant improved progression-free survival (PFS) and overall survival (OS) compared with first-generation (1G) treatment from the FLAURA trial. Recently two other 3G EGFR TKIs (aumolertinib and furmonertinib) have been approved in China for treatment of EGFR T790M+ NSCLC. Randomized Phase 3 trials of these two 3G EGFR TKIs have also demonstrated PFS over gefitinib respectively. Among these two Chinese home-grown, 3G EGFR TKIs, furmonertinib seems to most closely resemble osimertinib in terms of dosing regimen, efficacy and adverse events profile. In this article, we reviewed the clinical activity and adverse events of furmonertinib at 80 mg daily (approved dose), potential usage of 160 mg daily for CNS metastasis in EGFR+ NSCLC, and usage of 160 mg or 240 mg daily in EGFR exon20 insertion positive (EGFRex20ins+) NSCLC patients.

EGFR T790M testing through repeated liquid biopsy over time: a real-world multicentric retrospective experience

Background

About 15% of non-small cell lung cancers (NSCLCs) harbor epidermal growth factor receptor (EGFR) mutations. Upfront treatment with first and second generation EGFR tyrosine kinase inhibitors (1-2gen TKIs) is superior to chemotherapy. The most frequent resistance mechanism to 1-2gen TKIs is EGFR T790M mutation, which is targeted by osimertinib. T790M mutation can be revealed by liquid biopsy (LB) or by tissue rebiopsy (TB). LB is easily feasible but less sensitive than TB. We focused on repeated LBs and analyzed clinical features associated with EGFR T790M detection.

Methods

This is a retrospective multicenter observational study including EGFR-mutant NSCLC consecutive patients with disease progression (PD) after 1-2gen TKIs and with a first EGFR LB negative for T790M mutation, referred between 2016 and 2019. Aims of the study were to determine the prevalence of T790M mutation using LB in a real-life setting and the prevalence of T790M mutation by repeated LBs. We explored the association of T790M with clinical-pathological features and, through a survey, we evaluated the decision-making process behind LB request. Data on TBs were also collected.

Results

One hundred and ten patients were included in the study, for a total of 326 LBs. Median number of LB per patient was 3.0. The T790M prevalence through LB was 34.5%. Over time, significantly more LBs were requested "at clinical and radiological PD" and "at radiological PD" compared to "arbitrarily". The probability of finding the T790M mutation for a patient across each subsequent LB did not significantly change. Liver and lymph node PD were significantly correlated to T790M positivity. Notably, "at PD" compared to "arbitrarily" LB request and liver, bone or lymph node PD were correlated to the detection of any EGFR mutation in cfDNA. TB was performed in 59.7% of patients with a T790M negative LB and 18.8% of them were T790M positive. In most cases, TB was not feasible due to anatomical reasons. In our study population, the overall T790M prevalence-detected with both LB and TB-was 42.7%.

Conclusions

Repeated LB testing can be useful in a real-life scenario to detect EGFR T790M mutation.

L718Q/V mutation in exon 18 of EGFR mediates resistance to osimertinib: clinical features and treatment

Osimertinib, a mutant-specific third-generation epidermal growth factor receptor (EGFR) tyrosine kinase inhibitor (TKI), is emerging as the preferred first-line of treatment for EGFR-mutant lung cancer. However, osimertinib resistance inevitably develops among patients treated with the drug. The modal resistance mechanisms of osimertinib include the occurrence of epithelial transition factor (c-MET) amplification and C797S mutation, whereas rare mutations are presented as case reports. Recently, the L718Q/V mutation in exon 18 of EGFR has been reported to contribute to one of the possible mechanisms of resistance. The clinical features and subsequent treatment strategies for this mutation require further research. This study retrospectively enrolled NSCLC patients with the L718Q/V mutation from 2017 to 2021 at the Cancer Hospital of the University of the Chinese Academy of Sciences (Zhejiang Cancer Hospital), as well as additional patients with the same mutation from PubMed literature, to summarize the clinical features of the mutation. The association between the detection of L718Q/V and resistance to osimertinib, as well as impacts on the therapeutic process and outcome, was analyzed. We included a total of two patients diagnosed at Zhejiang Cancer Hospital and twelve patients from the literature. Of the fourteen total patients, 64.3% were male and 35.7% were female. The average age of the group was 60.2 years (range 45-72). A history of tobacco use was common among the group. In all of the cases we considered, the L718Q/V mutation was secondary to the L858R mutation. The second-generation TKI afatinib was found to provide a high disease control rate (DCR) (85.7%, 6/7) and relatively low objective response rate (ORR) (42/9%, 3/7). The median progression free survival (mPFS) for this treatment reached 2 months (1-6 months). The patients failed to benefit from chemotherapy combined with immunotherapy or other TKI medications. Due to the limited number of cases considered in this study, future studies should explore drugs that more precisely target the L718Q/V mutation of EGFR exon 18.

Efficacy and safety of Limertinib (ASK120067) in patients with locally advanced or metastatic EGFR T790M mutated non-small cell lung cancer: a multicenter, single-arm, phase 2b study

BACKGROUND

Limertinib (ASK120067) is a newly developed third-generation epidermal growth factor receptor (EGFR) tyrosine kinase inhibitor (TKI) targeting both sensitizing EGFR and EGFR T790M mutations. This study aimed to evaluate the efficacy and safety of limertinib in patients with locally advanced or metastatic EGFR T790M mutated non-small cell lung cancer (NSCLC).

METHODS

This is a single-arm, open-label, phase 2b study conducted at 62 hospitals across China. Patients with locally advanced or metastatic NSCLC with centrally confirmed EGFR T790M mutations in tumor tissue or blood plasma who progressed after first or second-generation EGFR-TKIs or with primary EGFR T790M mutations were enrolled. Patients received limertinib 160mg orally twice daily, until disease progression, or unacceptable toxicity. The primary endpoint was objective response rate (ORR) assessed by Independent Review Committee (IRC) per the Response Evaluation Criteria in Solid Tumors version 1.1. Secondary endpoints included disease control rate (DCR), progression-free survival (PFS), duration of response (DoR), overall survival (OS), and safety. Safety was assessed according to the National Cancer Institute Common Terminology Criteria for Adverse Events version 4.03.

RESULTS

From June 24, 2019 to Feb 25, 2021, a total of 301 patients were enrolled and received the treatment of limertinib. All patients entered the full analysis set (FAS) and safety set (SS). By the data cutoff date on Sept 9, 2021, 76 (25.2%) remained on treatment. The median follow-up time was 10.4 months (range 0.3-26.3). Based on FAS, the IRC-assessed ORR was 68.8% (95%CI 63.2%-74.0%) and DCR was 92.4% (95%CI 88.8%-95.1%). The median PFS was 11.0 months (95%CI 9.7-12.4), median DoR was 11.1 months (95%CI 9.6-13.8), and median OS was not reached (NR) (95%CI 19.7 months-NR). Objective responses were achieved across all pre-specified subgroups. For 99 (32.9%) patients with central nervous system (CNS) metastases, the ORR was 64.6% (95%CI 54.4%-74.0%), median PFS was 9.7 months (95%CI 5.9-11.6), and median DoR was 9.6 months (95%CI 8.1-15.2). For 41 patients who had evaluable CNS lesion, the confirmed CNS-ORR was 56.1% (95%CI 39.7%-71.5%) and median CNS-PFS was 10.6 months (95%CI 5.6-NE). In SS, 289 (96.0%) patients experienced at least one treatment related adverse event (TRAE), with the most common being diarrhea (81.7%), anemia (32.6%), rash (29.9%) and appetite decrease (28.2%). Grade ≥3 TRAEs occurred in 104 (34.6%) patients, with the most common including diarrhea (13.0%), hypokalemia (4.3%), anemia (4.0%) and rash (3.3%). TRAEs leading to dose interruption and dose discontinuation occurred in 24.6% and 2% of patients, respectively. No TRAE leading to death occurred.

CONCLUSION

Limertinib (ASK120067) demonstrated promising efficacy and an acceptable safety profile for the treatment of patients with locally advanced or metastatic EGFR T790M mutated NSCLC.

CLINICAL TRIAL INFORMATION

NCT03502850.

An evaluation of aumolertinib for the treatment of EGFR T790M mutation-positive non-small cell lung cancer

INTRODUCTION

Epidermal growth factor receptor tyrosine kinase inhibitors (EGFR-TKIs) can significantly improve patient prognosis when used on patients with EGFR-mutant non-small cell lung cancer (NSCLC), but those patients often develop acquired resistance after 9-14 months of treatment. These resistance mechanisms are complex and diverse, with the EGFR T790M mutation being the most common. Aumolertinib is a new third-generation EGFR-TKI that is highly selective for EGFR-sensitizing mutations and EGFR T790M resistance mutation.

AREAS COVERED

This review summarizes the mechanism of action, efficacy, and safety of aumolertinib for EGFR T790M mutation-positive NSCLC. The authors provide their expert opinions on the use of this drug, including its future prospects.

EXPERT OPINION

Aumolertinib has shown good efficacy and safety for advanced EGFR T790M mutation-positive NSCLC patients who have progressed after EGFR-TKI treatment. It is expected to become a new treatment option, and to aid the establishment of new treatment standards. A phase III clinical study is currently underway to evaluate the suitability of aumolertinib as a first-line treatment. At present, more drug combinations and different applicable populations are being further explored. Future challenges include exploring mechanisms of aumolertinib resistance and determining its efficacy in European and American populations.

Safety, Efficacy and Pharmacokinetics of Rezivertinib (BPI-7711) in Advanced Non-Small Cell Lung Cancer Patients with EGFR T790M Mutation: a Phase 1 Dose-Escalation and Dose-Expansion Study

INTRODUCTION

Rezivertinib (BPI-7711) is a novel third-generation epidermal growth factor receptor (EGFR) tyrosine kinase inhibitor selective for EGFR-sensitizing and T790M mutations. This study was designed to assess the safety, efficacy and pharmacokinetics of rezivertinib for patients having advanced non-small cell lung cancer (NSCLC) with EGFR T790M mutation.

METHODS

This phase 1 study (NCT03386955) was conducted across 20 sites in China. Patients received rezivertinib at six oral dose levels (30 mg, 60 mg, 120 mg, 180 mg, 240 mg, 300 mg) once daily until disease progression, unacceptable toxicity, or patient withdrawal. The primary end points were safety for the dose-escalation phase and objective response rate (ORR) by the blinded independent central review (BICR) for the total study population.

RESULTS

A total of 19 patients in dose-escalation phase using the standard 3+3 design principle and 153 patients in dose-expansion phase were enrolled from September 11, 2017 to August 23, 2019. The data cut-off date was on June 15, 2020. No dose limiting toxicity occurred in the dose-escalation phase. The treatment-related adverse events were observed in 82.0% (141 of 172) of patients and 17.4% (30 of 172) had ≥ grade 3, among which neutrophil count decreased (2.9%), leukopenia (2.9%) and pneumonia (2.9%) were the most common. The overall BICR-assessed ORR was 59.3% (102/172, 95% confidence interval [CI]: 51.6, 66.7), and the median progression-free survival was 9.7 (95% CI: 8.3, 11.1) months.

CONCLUSIONS

Rezivertinib showed promising efficacy with a manageable safety profile in patients with EGFR T790M-mutated advanced NSCLC. Further study is warranted.

Acquired Resistance Mechanism of EGFR Kinase Domain Duplication to EGFR TKIs in Non-Small Cell Lung Cancer

PURPOSE

Epidermal growth factor receptor kinase domain duplication (EGFR-KDD) is a rare and poorly understood oncogenic mutation in non-small cell lung cancer (NSCLC). We aimed to investigate the acquired resistance mechanism of EGFR-KDD against EGFR-TKIs.

MATERIALS AND METHODS

We identified EGFR-KDD in tumor tissue obtained from a patient with stage IV lung adenocarcinoma and established the patient-derived cell line SNU-4784. We also established several EGFR-KDD Ba/F3 cell lines: EGFR-KDD wild type (EGFR-KDDWT), EGFR-KDD domain 1 T790M (EGFR-KDDD1T), EGFR-KDD domain 2 T790M (EGFR-KDDD2T), and EGFR-KDD both domain T790M (EGFR-KDDBDT). We treated the cells with EGFR tyrosine kinase inhibitors (TKIs) and performed cell viability assays, immunoblot assays, and ENU (N-ethyl-N-nitrosourea) mutagenesis screening.

RESULTS

In cell viability assays, SNU-4784 cells and EGFR-KDDWT Ba/F3 cells were sensitive to 2nd generation and 3rd generation EGFR TKIs. In contrast, the T790M-positive EGFR-KDD Ba/F3 cell lines (EGFR-KDDT790M) were only sensitive to 3rd generation EGFR TKIs. In ENU mutagenesis screening, we identified the C797S mutation in kinase domain 2 of EGFR-KDDBDT Ba/F3 cells. Based on this finding, we established an EGFR-KDD domain 1 T790M/domain 2 cis-T790M+C797S (EGFR-KDDT/T+C) Ba/F3 model, which was resistant to EGFR TKIs and anti-EGFR monoclonal antibody combined with EGFR TKIs.

CONCLUSION

Our study reveals that the T790M mutation in EGFR-KDD confers resistance to 1st and 2nd generation EGFR TKIs, but is sensitive to 3rd generation EGFR TKIs. In addition, we identified that the C797S mutation in kinase domain 2 of EGFR-KDDT790M mediates a resistance mechanism against 3rd generation EGFR TKIs.

Efficacy of Aumolertinib (HS-10296) in Patients With Advanced EGFR T790M+ NSCLC: Updated Post-National Medical Products Administration Approval Results From the APOLLO Registrational Trial

INTRODUCTION

Aumolertinib (formerly almonertinib; HS-10296) is a novel third-generation EGFR tyrosine kinase inhibitor (TKI) with revealed activity against EGFR-sensitizing mutations and EGFR T790M mutation.

METHODS

Patients with locally advanced or metastatic NSCLC who developed an EGFR T790M mutation after progression on first- or second-generation EGFR TKI therapy were enrolled in this registrational phase 2 trial of aumolertinib at 110 mg orally once daily (NCT02981108). The primary end point was objective response rate (ORR) by independent central review.

RESULTS

A total of 244 patients with EGFR T790M-positive NSCLC were enrolled. The ORR by independent central review was 68.9% (95% confidence interval [CI]: 62.6-74.6). The disease control rate was 93.4% (95% CI: 89.6-96.2). The median duration of response was 15.1 months (95% CI: 12.5-16.6). The median progression-free survival was 12.4 months (95% CI: 9.7-15.0). Among 23 patients with assessable central nervous system (CNS) metastases, the CNS-ORR and CNS-disease control rate were 60.9% (95% CI: 38.5-80.3) and 91.3% (95% CI: 72.0-98.9), respectively. The median CNS-duration of response was 12.5 months (95% CI: 5.6-not reached). Treatment-related adverse events of more than or equal to grade 3 occurred in 16.4% of the patients, with the most common being increased blood creatine phosphokinase level (7%) and increased alanine aminotransferase level (1.2%). The relative dose density of aumolertinib was 99.2% in this study.

CONCLUSIONS

Aumolertinib is an effective and well-tolerated third-generation EGFR TKI for patients with EGFR T790M-positive advanced NSCLC after disease progression on first- and second-generation EGFR TKI therapy. On the basis of these findings, aumolertinib was approved in the People's Republic of China for patients positive for EGFR T790M NSCLC.

Comparing survival and treatment response of patients with acquired T790M mutation second-line osimertinib versus sequential treatment of chemotherapy followed by osimertinib: A real-world study

Purpose

To investigate the survival benefit with first/second generation epidermal growth factor receptor tyrosine kinase inhibitors (EGFR‐TKIs) and osimertinib in different treatment sequences.

Methods

We retrospectively screened 3807 patients diagnosed with cancer between 2013 and 2019 at Kaohsiung Chang Gung Memorial Hospital. In total, 76 patients with EGFR T790M mutation who received osimertinib after re‐biopsy or liquid biopsy were enrolled for the analysis.

Results

The median progression‐free survival (PFS), median overall survival (OS), and median OS2 of the 76 patients were 11.93, 66.53, and 29.57 months, respectively. A significant difference was observed in the disease control rate between those who received osimertinib treatment after chemotherapy (group A) and those who received osimertinib immediately following EGFR‐TKI therapy (group B) (34 [94.4%] vs. 31 [77.5%], p = 0.036). In addition, chronic obstructive pulmonary disease tended to be a poor prognostic factor for PFS and OS.

Conclusion

This real‐world analysis revealed that previous chemotherapy could affect the treatment outcomes of patients with non‐small cell lung cancer treated with osimertinib. Osimertinib treatment following first/second generation EGFR‐TKI treatment or chemotherapy resulted in improved survival benefit.

Real-world implementation of sequential targeted therapies for EGFR-mutated lung cancer

Background:

Epidermal growth factor receptor-mutated (EGFR⁺) non-small-cell lung cancer (NSCLC) patients failing tyrosine kinase inhibitors (TKI) can benefit from next-line targeted therapies, but implementation is challenging.

Methods:

EGFR⁺ NSCLC patients treated with first/second-generation (1G/2G) TKI at our institution with a last follow-up after osimertinib approval (February 2016), were analyzed retrospectively, and the results compared with published data under osimertinib.

Results:

A total of 207 patients received erlotinib (37%), gefitinib (16%) or afatinib (47%). The median age was 66 years, with a predominance of female (70%), never/light-smokers (69%). T790M testing was performed in 174/202 progressive cases (86%), positive in 93/174 (53%), and followed by osimertinib in 87/93 (94%). Among the 135 deceased patients, 94 (70%) received subsequent systemic treatment (43% chemotherapy, 39% osimertinib), while 30% died without, either before (4%) or after progression, due to rapid clinical deterioration (22%), patient refusal of further therapy (2%), or severe competing illness (2%). Lack of subsequent treatment was significantly (4.5x, p < 0.001) associated with lack of T790M testing, whose most frequent cause (in approximately 50% of cases) was also rapid clinical decline. Among the 127 consecutive patients with failure of 1G/2G TKI started after November 2015, 47 (37%) received osimertinib, with a median overall survival of 36 months versus 24 and 21 months for patients with alternative and no subsequent therapies (p = 0.003).

Conclusion:

Osimertinib after 1G/2G TKI failure prolongs survival, but approximately 15% and 30% of patients forego molecular retesting and subsequent treatment, respectively, mainly due to rapid clinical deterioration. This is an important remediable obstacle to sequential TKI treatment for EGFR⁺ NSCLC. It pertains also to other actionable resistance mechanisms emerging under 1G/2G inhibitors or osimertinib, whose rate for lack of next-line therapy is similar (approximately 35% in the FLAURA/AURA3 trials), and highlights the need for closer monitoring alongside broader profiling of TKI-treated EGFR⁺ NSCLC in the future.

Real-world data on treatment outcomes in EGFR-mutant non-small-cell lung cancer patients receiving osimertinib in second or further lines

Aims: This study describes real-world outcomes of pretreated EGFR T790M-positive (T790M⁺) advanced non-small-cell lung cancer patients progressing after first- or second-generation tyrosine kinase inhibitors and receiving osimertinib, compared with T790M-negative (T790M^-) patients. We have also described progression patterns and treatment sequences. Patients & methods: This is a retrospective multicenter Italian observational study including consecutive Caucasian patients referred between 2014 and 2018. Results: 167 patients were included. Median progression-free survival was 9.8 months (95% CI: 8.3-13.3) for T790M⁺ and 6.0 months (95% CI: 4.9-7.2) for T790M^- patients, respectively. Median overall survival was 20.7 months (95% CI: 18.9-28.4) for T790M⁺ and 10.6 months (95% CI: 8.6-23.6) for T790M^- patients, respectively. The T790M mutation correlated with absence of new sites of disease. After progression, most T790M⁺ patients continued osimertinib, whereas most T790M^- patients received a different treatment line. Conclusion: Better outcomes were shown in patients receiving osimertinib. A more limited progression pattern for T790M⁺ was suggested.

Osimertinib alone as second-line treatment for brain metastases (BM) control may be more limited than for non-BM in advanced NSCLC patients with an acquired EGFR T790M mutation

BACKGROUND

This study was designed to investigate the difference between brain metastases (BM) and non-brain metastases (non-BM) treated by osimertinib in advanced patients with an acquired EGFR T790M mutation after obtaining first-generation EGFR-TKI resistance.

METHODS

A total number of 135 first-generation EGFR-TKI-resistant patients with an acquired EGFR T790M mutation were retrospectively analyzed. The patients were divided into BM and non-BM groups. According to the type of treatment (whether brain radiotherapy), the BM patients were divided into an osimertinib combined with brain radiotherapy group and an osimertinib without brain radiotherapy group. In addition, according to the type of BM (the sequence between BM and osimertinib), the BM patients were subdivided into an osimertinib after BM group (initial BM developed after obtaining first-generation EGFR-TKI resistance) and an osimertinib before BM group (first-generation EGFR-TKI resistance then osimertinib administration performed; initial BM was not developed until osimertinib resistance). The progression-free survival (PFS) and overall survival (OS) were evaluated. The primary endpoint was OS between BM and no-BM patients. The secondary endpoints were PFS of osimertinib, and OS between brain radiotherapy and non-brain radiotherapy patients.

RESULTS

A total of 135 patients were eligible and the median follow-up time of all patients was 50 months. The patients with BM (n = 54) had inferior OS than those without BM (n = 81) (45 months vs. 55 months, P = 0.004). And in BM group, the OS was longer in patients that received osimertinib combined with brain radiotherapy than in those without brain radiotherapy (53 months vs. 40 months, P = 0.014). In addition, the PFS was analysed according to whether developed BM after osimertinib resistance. The PFS of the patients that developed BM after acquiring osimertinib resistance was shorter than that without BM development, whether patients developed initial BM after first-generation EGFR-TKI resistance (7 months vs. 13 months, P = 0.003), or developed non-BM after first-generation EGFR-TKI resistance (13 months vs. 17 months, P < 0.001).

CONCLUSIONS

In advanced patients with an acquired EGFR T790M mutation after obtaining first-generation EGFR-TKI resistance, osimertinib may be more limited in its control in BM than in non-BM. Also, osimertinib combined with brain radiotherapy may improve the survival time of BM patients.

Resistance Profile of Osimertinib in Pre-treated Patients With EGFR T790M-Mutated Non-small Cell Lung Cancer

Background: Osimertinib efficacy in pre-treated patients with epidermal growth factor receptor (EGFR) T790M-mutated non-small cell lung cancer (NSCLC) has been demonstrated in clinical trials, but real-world data, particularly regarding resistance profile, remains limited. This study aims to analyze the resistance mechanisms acquired after treatment with Osimertinib.

Methods: Clinical outcomes and molecular results from re-biopsies at the time of osimertinib progression of EGFR T790M-mutated NSCLC patient were analyzed.

Results: Twenty-one patients with stage IV adenocarcinoma were included [median 69 years; 57.1% female; 85.7% never-smokers; 23.8% ECOG performance status (PS) ≥2]. Median PFS and OS were 13.4 (95% CI: 8.0–18.9) and 26.4 (95% IC: 8.9–43.8) months, respectively. At the time of analysis, 10 patients had tumor progression (47.6%). T790M loss occurred in 50%, being associated with earlier progression (median PFS 8.1 vs. 21.4 months, p = 0.011). Diverse molecular alterations were identified, including C797S mutation (n = 1), PIK3CA mutation (n = 2), MET amplification (n = 1), CTNNB1 mutation (n = 1), and DCTN1-ALK fusion (n = 1). Histological transformation into small cell carcinoma occurred in one patient.

Conclusions: This real-world life study highlights the relevance of re-biopsy at the time of disease progression, contributing to understand resistance mechanisms and to guide treatment strategies.

Detection and quantification of EGFR T790M mutation in liquid biopsies by droplet digital PCR

Background

Liquid biopsy allows the identification of targetable cancer mutations in a minimally invasive manner. In patients with advanced non-small cell lung cancer (NSCLC), droplet digital PCR (ddPCR) is increasingly used to genotype the epidermal growth factor receptor (EGFR) gene in circulating cell-free DNA (cfDNA). However, the sensitivity of this method is still under debate. The aim of this study was to implement and assess the performance of a ddPCR assay for detecting the EGFR T790M mutation in liquid biopsies.

Methods

A ddPCR assay was optimized to detect the EGFR T790M mutation in plasma samples from 77 patients with NSCLC in progression.

Results

Our ddPCR assay enabled the detection and quantification of the EGFR T790M mutation at cfDNA allele frequency as low as 0.5%. The mutation was detected in 40 plasma samples, corresponding to a positivity rate of 52%. The number of mutant molecules per mL of plasma ranged from 1 to 6,000. A re-biopsy was analyzed for 12 patients that had a negative plasma test and the mutation was detected in 2 cases. A second liquid biopsy was performed for 6 patients and the mutation was detected in 3 cases.

Conclusions

This study highlights the value of ddPCR to detect and quantify the EGFR T790M mutation in liquid biopsies in a real-world clinical setting. Our results suggest that repeated ddPCR tests in cfDNA may obviate tissue re-biopsy in patients unable to provide a tumor tissue sample suitable for molecular analysis.

Safety, Efficacy, and Pharmacokinetics of Almonertinib (HS-10296) in Pretreated Patients With EGFR-Mutated Advanced NSCLC: A Multicenter, Open-label, Phase 1 Trial

INTRODUCTION

Almonertinib (HS-10296) is a novel, third-generation EGFR tyrosine kinase inhibitor (EGFR TKI) that targets both EGFR-sensitizing and T790M resistance mutations. This first-in-human trial aimed to evaluate the safety, efficacy, and pharmacokinetics of almonertinib in patients with locally advanced or metastatic EGFR mutation-positive NSCLC that had progressed after pevious EGFR TKI therapy.

METHODS

This phase 1, open-label, multicenter clinical trial (NCT0298110) included dose-escalation (55, 110, 220, and 260 mg) and dose-expansion cohorts (55, 110, and 220 mg) with once daily oral administration of almonertinib. In each expansion cohort, tumor biopsies were obtained for the determination of EGFR T790M status. The safety, tolerability, antitumor activity, and pharmacokinetics of almonertinib were evaluated.

RESULTS

A total of 120 patients (26 patients in the dose-escalation cohort and 94 patients in the dose-expansion cohort) were enrolled. The maximum tolerated dose was not defined in the dose-escalation phase; the 260 mg regimen was not further evaluated in the dose-expansion phase owing to safety concerns and saturation of exposure. The most common treatment-related grade greater than or equal to 3 adverse events were increased blood creatine phosphokinase (10%) and increased alanine aminotransferase (3%). Among 94 patients with the EGFR T790M mutation in the dose-expansion cohort, the investigator-assessed objective response rate and disease control rate were 52% (95% confidence interval [CI]: 42-63) and 92% (95% CI: 84-96), respectively. Median progression-free survival was 11.0 months (95% CI: 9.5-not reached) months.

CONCLUSIONS

Almonertinib is safe, tolerable and effective for patients with locally advanced or metastatic NSCLC harboring the EGFR T790M mutation who were pretreated with EGFR TKIs.

ASTRIS, a large real-world study to evaluate the efficacy of osimertinib in epidermal growth factor receptor T790M mutation-positive non-small cell lung cancer patients: Clinical characteristics and genotyping methods in a Spanish cohort

PURPOSE

Osimertinib has proven efficacy in EGFR T790M mutation-positive non-small cell lung cancer (NSCLC) patients; however, its benefits have not been evaluated in a real-world setting.

METHODS

ASTRIS is a single-arm, open-label, multinational study to evaluate the efficacy and safety of osimertinib for the treatment of EGFR T790M mutation-positive NSCLC. We present the study design and preliminary cut-off analysis results (as of October 2017) describing the baseline characteristics and methodology for T790M mutation detection in the Spanish cohort.

RESULTS

The Spanish cohort included 131 patients from a total 3014 patients. Forty patients (28.1%) were still undergoing therapy at the time of cut-off; 68.7% were women and 97.7% were Caucasian, with a mean age of 64.8 (SD 11.7) years. The most common type of sample for evaluating T790M mutations was tissue (55.0%), and samples were obtained from the primary tumor in 61.1% of cases. Mutation analysis was performed by the local laboratory in 60.3% of cases and using the Roche Cobas® EGFR assay in 43.5% of cases.

CONCLUSIONS

ASTRIS is expected to confirm the benefits of osimertinib in a real-world setting. Data on real-world practices for the detection of the EGFR T790M mutation may provide additional information for the designing of guidelines for best practices.

Durable complete response after afatinib and crizotinib in an advanced non-small cell lung cancer patient with EGFR L861Q mutation and acquired MET amplification: a case report

Epidermal growth factor receptor (EGFR) L861Q mutation is a non-classical mutation, with a low incidence, poor response, and uncertain resistance mechanisms when treated by an EGFR tyrosine kinase inhibitor (EGFR-TKI). The liver is one of the most common distant organs to metastasize in nonsmall cell lung cancer (NSCLC), and achieving complete remission treatment for the liver is difficult. In this report, a patient was diagnosed with advanced lung adenocarcinoma harboring the EGFR L861Q mutation and responded well to afatinib for 16 months. Complete response and partial response (PR) appeared in the liver metastasis and primary lesion respectively. Following this, afatinib plus crizotinib overcame the acquired resistance of MET amplification and brought about the complete remission of the liver for 10 months. Interestingly, the liver remission endured for 22 months and persisted even when the disease progressed and the EGFR T790M mutation emerged. To our knowledge, this is the first time that afatinib induced longterm liver remission in a patient with an EGFR non-classical mutation, and in whom crizotinib with afatinib proved to be a reliable treatment for overcoming MET amplification resistance with an EGFR non-classical mutation. This precise and individualized gene-based treatment significantly prolonged the survival time of this stage IV case with brain metastases yielding 26 months of progression-free survival (PFS) time and more than 3 years of overall survival time.

BBB-penetrating codelivery liposomes treat brain metastasis of non-small cell lung cancer with EGFRT790M mutation

EGFR TKI therapy has become a first-line regimen for non-small cell lung cancer (NSCLC) patients with EGRF mutations. However, there are two big challenges against effective therapy--the secondary EGFR mutation-associated TKI resistance and brain metastasis (BMs) of lung cancer. The BMs is a major cause of death for advanced NSCLC patients, and the treatment of BMs with TKI resistance remains difficult.

Methods: Tumor-associated macrophages (TAM) is a promising drug target for inhibiting tumor growth, overcoming drug resistance, and anti-metastasis. TAM also plays an essential role in regulating tumor microenvironment. We developed a dual-targeting liposomal system with modification of anti-PD-L1 nanobody and transferrin receptor (TfR)-binding peptide T12 for codelivery of simvastatin/gefitinib to treat BMs of NSCLC.

Results: The dual-targeting liposomes could efficiently penetrate the blood-brain barrier (BBB) and enter the BMs, acting on TAM repolarization and reversal of EGFR^T790M-associated drug resistance. The treatment mechanisms were related to the elevating ROS and the suppression of the EGFR/Akt/Erk signaling pathway.

Conclusion: The dual-targeting liposomal codelivery system offers a promising strategy for treating the advanced EGFR^T790M NSCLC patients with BMs.

The Status of the EGFR T790M Mutation is associated with the Clinical Benefits of Osimertinib Treatment in Non-small Cell Lung Cancer Patients: A Meta-Analysis

Background and Purpose: Pervious studies have demonstrated that the loss of EGFR T790M after Osimertinib treatment may be the cause of Osimertinib resistance. Here, we conducted a meta-analysis to evaluate the association between the persistence of EGFR T790M and the clinical benefits of Osimertinib in non-small cell lung cancer (NSCLC) patients with baseline EGFR T790M mutation.

Experimental design and Methods: PUBMED, EMBASE, and Cochrane databases were searched for eligible studies that provided the survival outcomes including overall survival (OS), progression-free survival (PFS) or time to discontinuation (TTD) data for each patient treated with Osimertinib with the status of the T790M mutation tested after Osimertinib resistance. The hazard ratios (HRs) and their 95% confidence intervals (CI) were calculated for each study.

Results: In total, eight eligible studies were included in the analysis, among which six studies provided the data on PFS, and the other two studies provided the TTD data. Overall, 312 patients (151 patients with the persistence of T790M) were identified. The persistence of T790M was associated with longer PFS (HR, 0.40; 95% CI, 0.19-0.84; P=0.01) and TTD (HR, 0.54; 95% CI, 0.39-0.76; P=0.0004). Furthermore, overall analysis the survival outcomes including PFS and TTD subgroups also showed preferable clinical benefits for patients with the T790M persistence (HR, 0.57; 95%CI, 0.45-0.73; P<0.00001).

Conclusions: Our findings confirm the persistence of T790M is associated with the clinical benefits of Osimertinib in NSCLC patients with baseline EGFR T790M mutation treated with Osimertinib.

Dynamic changes of acquired T790M mutation and small cell lung cancer transformation in a patient with EGFR-mutant adenocarcinoma after first- and third-generation EGFR-TKIs: a case report

Epithelial growth factor receptor (EGFR) T790M mutation and small cell lung cancer (SCLC) transformation are well-known resistance mechanisms acquired during treatment with EGFR tyrosine kinase inhibitors (TKIs). Various mechanisms sometimes coexist in patients. Here, we report a 57-year-old female diagnosed with stage IV lung adenocarcinoma, who harbored an EGFR exon 19 deletion mutation. This patient initially received gefitinib and progressed after 14 months. A repeat biopsy was performed, and the original EGFR exon 19 deletion and acquired exon 20 T790M mutation were identified. Then, pemetrexed plus carboplatin was administered as second-line and osimertinib as third-line treatment. Rapid progression and mixed response were observed after 2 months on osimertinib, with stable disease of the primary lung lesion but rapid growth of a right lower chest mass. The progressive chest lesion underwent biopsy, and the SCLC transformation was revealed. Furthermore, the patient was treated with etoposide and cisplatin, and she achieved disease control for 4 months. A fourth biopsy both for the primary lung lesion and the chest mass were finally conducted. Interestingly, the histopathology of the two different lesions showed adenocarcinoma and SCLC, respectively. The patient then rapidly suffered brain metastasis, and no EGFR mutations were detected in her cerebrospinal fluid (CSF). Overall survival (OS) of the patient was 29 months. This patient experienced concomitant resistance mechanisms of T790M mutation and SCLC transformation, which might have resulted from intra-tumor heterogeneity and drug-induced selection. Ultimately, this case reminds us that repeat biopsies are essential for patients receiving EGFR-TKIs in order to make appropriate treatment decisions according to the diverse mechanisms of acquired resistance.

Real-world use of osimertinib in non-small cell lung cancer: ASTRIS study Korean subgroup analysis

Objective: ASTRIS is a large real-world, open-label, multinational clinical study of osimertinib in patients with epidermal growth factor receptor (EGFR) T790M mutation-positive advanced non-small cell lung cancer (NSCLC) who have previously received a tyrosine kinase inhibitor (TKI). We report data from the Korean ASTRIS subgroup.Methods: Adult patients with locally advanced or metastatic NSCLC with a confirmed T790M mutation, WHO performance status of 0-2 and prior EGFR-TKI therapy, received osimertinib 80 mg once daily. Efficacy outcomes were overall survival (OS), investigator-assessed response rate (RR) and progression-free survival (PFS), and time to treatment discontinuation (TTD).Results: At data cut-off (20 October 2017), 466 Korean patients were enrolled. Baseline EGFR molecular testing was mainly performed on biopsied tissue (75.1%). Baseline mutations co-occurring with T790M included exon 19 deletions (60.7%) and L858R (32.8%). 1-year OS was 82.7% (OS data not matured at data cut-off). Overall, RR was 71.0%, median PFS was 12.4 months and median TTD was 15.0 months. In patients with/without CNS metastases, RR was 68.0% and 79.6%, respectively; median PFS, 10.8 and 11.0 months, respectively; and median TTD, 11.2 and 14.7 months, respectively. Overall, 31.1% of patients experienced ≥1 adverse event (AE), leading to dose modification (12.0%), discontinuation (5.2%) or death (2.8%). Serious AEs (24.9%) included pulmonary embolism (1.7%), pleural effusion (1.7%), and pneumonia (1.5%).Conclusion: In this real-world subgroup analysis of Korean patients in the ASTRIS study, osimertinib demonstrated comparable clinical efficacy to that attained in the global ASTRIS study and other clinical trials, with no new safety concerns.

EGFR T790M detection rate in lung adenocarcinomas at baseline using droplet digital PCR and validation by ultra-deep next generation sequencing

Background

Routine testing of baseline EGFR T790M mutation may have important clinical impact but many discordant data have been reported regarding the diagnostic, prognostic and predictive role of this marker. In this study we aimed to assess T790M frequency in 164 untreated EGFR-mutated NSCLCs using methods with different sensitivity as well as to analyze the relationship between baseline T790M mutation status, patient's clinicopathologic features and tyrosine kinase inhibitors (TKI) treatment outcomes.

Methods

We compared the diagnostic performance, sensitivity and specificity of three methods, namely MALDI-TOF mass spectrometry (MS), Allele-Specific Real Time PCR (AS-PCR), droplet digital PCR (ddPCR). Ultra-deep next generation sequencing (NGS) validation of T790M-mutant NSCLCs was performed using SiRe^® panel.

Results

Baseline T790M occurred in 17% of the tumors. Intermediately sensitive techniques such as MALDI-TOF MS (detection limit of T790M ≥5%) allow to detect T790M in 2% of cases exhibiting mutant-allele fractions ranging from 11.5% to 17%. Median overall survival (OS) in these patients was poor (7.3 months) and progression free survival (PFS) was of 3.3 months in patients treated with a 1st generation EGFR TKI. The remaining T790M-positive cases showed very low mutant-allele fractions ranging from 0.07% to 0.38% and required highly sensitive methods such as ddPCR and NGS to be identified. All these cases showed a concurrent sensitizing EGFR mutation (mainly exon 19 deletion), and clinicopathological features similar to those observed in EGFR mutant cancers. Median OS of these patients was 27 months while median PFS after TKI treatment was 20 months.

Conclusions

Routine test of baseline EGFR T790M may have an important role in the prediction to EGFR TKI therapy response and should be performed using highly sensitive and quantitative methods, such as ddPCR and NGS, in order to reliably distinguish NSCLCs with high or very low T790M mutant-allele fraction.

Clinical Features and Progression Pattern of Acquired T790M-positive Compared With T790M-negative EGFR Mutant Non-small-cell Lung Cancer: Catching Tumor and Clinical Heterogeneity Over Time Through Liquid Biopsy

BACKGROUND

Clinical-pathologic predictors of acquired T790M epidermal growth factor receptor (EGFR) mutation in Caucasian patients with non-small-cell lung cancer (NSCLC) progressing after first-/second-generation tyrosine kinase inhibitors (TKIs) is an open field for research. Similarly, the best time point for T790M detection by liquid or tissue biopsy after disease progression is currently matter of debate.

PATIENTS AND METHODS

This is an observational study at 7 Italian centers enrolling patients with EGFR-mutant NSCLC progressing after first-/second-generation EGFR TKIs, between 2014 and 2018, aiming at comparing baseline clinical-pathologic features and progression patterns in acquired T790M-positive compared with T790M-negative cases.

RESULTS

A total of 235 patients received first-line treatment with gefitinib (N = 126; 53%), erlotinib (N = 51; 22%), or afatinib (N = 58; 25%). In 120 (51%) cases, T790M was detected in liquid biopsy, tissue biopsy, or both. Age younger than 65 years (P = .037), the presence of common mutations (P = .004), and better response to first-line TKI (P = .023) were correlated with T790M positivity. T790M detection was associated with higher number of new progressing sites (P = .04), liver progression (P = .002), and a lower frequency of lung metastases (P = .027). When serial liquid biopsies were performed (N = 15), an oligoprogressive disease was correlated with a negative test outcome, whereas systemic progression was observed at the time of T790M positivity.

CONCLUSION

This study on a Caucasian population showed that age, type of EGFR mutation at diagnosis, response to first-line treatment, and peculiar progression pattern are associated with T790M status. Serial liquid biopsy might be useful for treatment selection, especially when tissue rebiopsy is not feasible.

Analysis of resistance mechanisms to abivertinib, a third-generation EGFR tyrosine kinase inhibitor, in patients with EGFR T790M-positive non-small cell lung cancer from a phase I trial

BACKGROUND

Resistance to third-generation epidermal growth factor receptor (EGFR) tyrosine kinase inhibitors (TKIs) presents a major clinical challenge in advanced non-small cell lung cancer (NSCLC). Here, we report resistance mechanisms to abivertinib, a novel third-generation EGFR TKI, from a phase I dose-escalation/expansion study (NCT02330367).

METHODS

Patients with EGFR T790M-positive advanced NSCLC and progression on prior EGFR TKIs received abivertinib in dose escalation (50-350 mg twice daily [BID]) or expansion (300 mg BID) cohorts. Patients enrolled at Guangdong Lung Cancer Institute who underwent next-generation sequencing (NGS)-based genomic profiling upon abivertinib progression (prior to October 30, 2018) were enrolled in this exploratory analysis.

FINDINGS

Thirty of 73 patients enrolled were eligible for resistance analysis. Upon abivertinib progression, 27 patients provided plasma samples (six patients also provided paired samples from the progression sites) and three patients only provided tissue samples from the progression sites for NGS. A heterogeneous landscape of resistance to abivertinib was observed: 15% (4/27) experienced EGFR T790M loss and 13% (4/30) developing EGFR tertiary mutations including C797S. EGFR amplification was observed in 11 patients (37%), and considered a putative resistance mechanism in seven (23%) patients. Other EGFR-independent resistance mechanisms involved CDKN2A, MET, PIK3CA, HER2, TP53, Rb1 and small-cell lung cancer transformation.

INTERPRETATION

Our findings reveal a heterogenous pattern of resistance mechanisms to abivertinib which is distinct from that previously reported with osimertinib. EGFR amplification was the most common resistance mechanism in this cohort. FUND: The National Key R&D Program of China (Grant No. 2016YFC1303800), Key Lab System Project of Guangdong Science and Technology Department - Guangdong Provincial Key Lab of Translational Medicine in Lung Cancer (Grant No. 2012A061400006/2017B030314120).

Bio-Inspired NanoVilli Chips for Enhanced Capture of Tumor-Derived Extracellular Vesicles: Toward Non-Invasive Detection of Gene Alterations in Non-Small Cell Lung Cancer

Tumor-derived extracellular vesicles (EVs) present in bodily fluids are emerging liquid biopsy markers for non-invasive cancer diagnosis and treatment monitoring. Because the majority of EVs in circulation are not of tumor origin, it is critical to develop new platforms capable of enriching tumor-derived EVs from the blood. Herein, we introduce a biostructure-inspired NanoVilli Chip, capable of highly efficient and reproducible immunoaffinity capture of tumor-derived EVs from blood plasma samples. Anti-EpCAM-grafted silicon nanowire arrays were engineered to mimic the distinctive structures of intestinal microvilli, dramatically increasing surface area and enhancing tumor-derived EV capture. RNA in the captured EVs can be recovered for downstream molecular analyses by reverse transcription Droplet Digital PCR. We demonstrate that this assay can be applied to monitor the dynamic changes of ROS1 rearrangements and epidermal growth factor receptor T790M mutations that predict treatment responses and disease progression in non-small cell lung cancer patients.

Different characteristics and survival in non-small cell lung cancer patients with primary and acquired EGFR T790M mutation

Primary epidermal growth factor receptor (EGFR) T790M mutation can be occasionally identified in previous untreated nonsmall cell lung cancer (NSCLC) patients. To compare clinical characteristics and outcomes in patients with primary and acquired EGFR T790M mutation, we collected the data of patients diagnosed with EGFR mutation from 2012 to 2017 in Shanghai Chest Hospital. Primary EGFR T790M mutation was identified in 61 patients (1.1%; 95% confidence interval (CI): 0.8%-1.3%) of 5685 TKI-naive EGFR mutant patients. Acquired T790M mutation was detected in 98 patients (50.3%; 95%CI: 43.2%-57.3%) of 195 TKI-treated patients. T790M mutation always coexisted with sensitizing EGFR mutations. Primary EGFR T790M always coexisted with 21L858R (46/61) whereas acquired T790M coexisted with 19del (68/98), (p < 0.001). Among them, 18 patients with primary T790M mutation received osimertinib and 72 patients with acquired T790M mutation received osimertinib. The median progression-free survival (PFS) of osimertinib was significantly longer in primary T790M group (17.0 months, 95%CI:14.0-20.0 months) compared to acquired T790M group (10.0 months, 95%CI:8.6-11.4 months, p = 0.022). However, the median overall survival (OS) of acquired T790M mutation patients was significantly longer compared to that of primary T790M mutation patients who received osimertinib (50.4 months vs. 29.9 months, p = 0.016). Our findings suggest that primary T790M mutation likely coexists with 21L858R while acquired mutation likely coexists with 19del. Both mutations showed good response to osimertinib. Patients with primary T790M mutation experienced greater benefits from osimertinib. However, patients with acquired T790M mutation had a better overall survival during the entire clinical treatment.

Differential MicroRNA Expression between EGFR T790M and L858R Mutated Lung Cancer

Background

MicroRNAs (miRNAs) are short, non-coding RNAs that mediate post-transcriptional gene regulation. They are commonly deregulated in human malignancies, including non-small cell lung cancer (NSCLC). The aim of this study is to investigate miRNA expression in T790M-mutated NSCLC resistant to epidermal growth factor receptor (EGFR) tyrosine kinase inhibitors.

Methods

Six cases of resected NSCLC harboring the T790M mutation were examined. We performed miRNA time polymerase chain reaction (PCR) array profiling using EGFR T790M-mutated NSCLC and L858R-mutated NSCLC. Once identified, miRNAs that were differentially expressed between the two groups were validated by quantitative real-time polymerase chain reaction (qRT-PCR).

Results

miRNA PCR array profiling revealed three up-regulated miRNAs whose expression levels were altered 4.0-fold or more in the EGFR T790M mutation group than in the L858R group: miR-1 (fold change, 4.384), miR-196a (fold change, 4.138), and miR-124 (fold change, 4.132). The three differentially expressed miRNAs were validated by qRT-PCR, and they were found to be overexpressed in the T790M group relative to L858R group. In particular, expression levels of miR-1 and miR-124 were significantly higher in the T790M group (p-value of miR-1 = .004, miR-124 = .007, miR-196a = .096).

Conclusions

MiR-1, miR-124, and miR-196a are overexpressed in EGFR T790M mutated NSCLC.

EGFR T790M ctDNA testing platforms and their role as companion diagnostics: Correlation with clinical outcomes to EGFR-TKIs

Somatic mutation in the epidermal growth factor receptor (EGFR) predict clinical response to EGFR tyrosine kinase inhibitors in non-small cell lung cancer (NSCLC) and is a promising target for personalised medicine. EGFR mutations have prognostic value. Initially patients respond well to tyrosine kinase inhibitors but finally they would develop resistance and about 50% of this resistance can be attributed to the emergence of EGFR resistant mutation, T790M. This necessitates the need for genetic testing for clinical management of patients. Molecular testing has become the standard of care in patients with NSCLCs based on the recommendations of standard guidelines. Though there are several platforms for EGFR mutation detection, highly sensitive platforms for clinical applicability as companion diagnostics for ctDNA based testing are emerging. Due to the dynamic changes in the T790M mutation during tyrosine kinase inhibitor (TKI) treatment, real-time monitoring of these genetic alterations is mandate for planning treatment strategies. With the advent of third generation TKIs that potentially target T790M, improvement in clinical outcome is documented in patients with NSCLCs. Managing these outcomes with appropriate companion diagnostics using ctDNA in early detection of these genetic alterations will improve patient care.

Association Between EGFR T790M Status and Progression Patterns During Initial EGFR-TKI Treatment in Patients Harboring EGFR Mutation

BACKGROUND

Emergence of the T790M point mutation in exon 20 of the epidermal growth factor receptor (EGFR) is the most common mechanism of resistance to EGFR tyrosine kinase inhibitors (EGFR-TKIs). The aim of this study was to investigate the association between T790M mutation status and the progression patterns during EGFR-TKI treatment.

METHODS

We reviewed 181 patients with advanced non-small-cell lung cancer harboring EGFR mutation, who were evaluated for T790M mutation status after initial EGFR-TKI failure (gefitinib, erlotinib, or afatinib). We retrospectively investigated the patient characteristics, initial EGFR-TKI response, T790M mutation status, subsequent treatment after initial EGFR-TKIs, timing of re-biopsy, and progression patterns during the EGFR-TKI treatment.

RESULTS

After the resistance to the EGFR-TKIs, the T790M mutation was identified in 87 (48%) of 181 patients. Seventy-three (40%) patients had solitary lesion progression, and 108 (60%) had multiple lesion progression during the initial EGFR-TKI treatment. The prevalence of the T790M mutation was significantly greater in patients with solitary lesion progression than those with multiple lesion progression (58% vs. 24%; P < .0001). The overall response rate and progression-free survival on initial EGFR-TKIs were significantly better in patients who acquired T790M after failure of EGFR-TKIs than those without T790M (overall response rate, 80% vs. 60%; P = .0033 and progression-free survival, 11.4 vs. 9.3 months; P = .0050). The multivariate analysis showed that gender, initial EGFR-TKI response, and progression patterns were significantly associated with T790M mutation status.

DISCUSSION

The progression patterns during initial EGFR-TKIs and initial EGFR-TKI response are associated with the T790M mutation.

AT-101 enhances gefitinib sensitivity in non-small cell lung cancer with EGFR T790M mutations

Background

Although epidermal growth factor receptor tyrosine kinase inhibitors (EGFR TKIs) have become the standard care of patients with advanced EGFR-mutant non-small cell lung cancer (NSCLC), development of acquired resistance is inevitable. A secondary mutation of threonine 790 (T790M) is associated with approximately half of the cases of acquired resistance. Strategies or agents to overcome this type of resistance are still limited. In this study, enhanced antitumor effect of AT-101, a-pan-Bcl-2 inhibitor, on gefitinib was explored in NSCLC with T790M mutation.

Methods

The effect of cotreatment with AT-101 and gefitinib on the viability of NSCLC cell lines harboring acquired T790M mutation was investigated using the MTT assay. The cellular apoptosis of NSCLC cells after cotreatment with AT-101 and gefitinib was assessed by FITC-annexin V/PI assay and Western blots analysis. The potential underlying mechanisms of the enhanced therapeutic effect for AT-101 was also studied using Western blots analysis. The in vivo anti-cancer efficacy of the combination with AT-101 and gefitinib was examined in a mouse xenograft model.

Results

In this study, we found that treatment with AT-101 in combination with gefitinib significantly inhibited cell proliferation, as well as promoted apoptosis of EGFR TKIs resistant lung cancer cells. The apoptotic effects of the use of AT-101 was related to the blocking of antiapoptotic protein: Bcl-2, Bcl-xl, and Mcl-1 and downregrulation of the molecules in EGFR pathway. The observed enhancements of tumor growth suppression in xenografts supported the reverse effect of AT-101 in NSCLC with T790M mutation, which has been found in in vitro studies before.

Conclusions

AT-101 enhances gefitinib sensitivity in NSCLC with EGFR T790M mutations. The addition of AT-101 to gefitinib is a promising strategy to overcome EGFR TKIs resistance in NSCLC with EGFR T790M mutations.