Integrative Genomic Analysis of Drug Resistance in MET Exon 14 Skipping Lung Cancer Using Patient-Derived Xenograft Models

Background Non-small cell lung cancer (NSCLC) driven by MET exon 14 skipping (METex14) occurs in 3-4% of NSCLC cases and defines a subset of patients with distinct characteristics. MET targeted therapy has led to strong clinical responses, however little is known about aquired resistance to drugs in these patients. Patient derived xenograft (PDX) models are recognized as excellent preclinical models to facilitate the understanding of the mechanisms underlying drug resistance. Methods We describe a patient case harboring METex14 who exhibited drug resistance after treatment with crizotinib. Subcutaneous xenografts were generated from pretreatment and post-resistance patient specimens. PDX mice were then treated with MET inhibitors (crizotinib and tepotinib) to evaluate their drug response. DNA and RNA sequencing analysis was performed on patient tumor specimens and matching xenografts. Results PDXs preserved most of the histological and molecular profiles of the parental tumors. Drug resistance to MET targeted therapy was confirmed in PDX models through in vivo drug analysis. Newly aquired MET D1228N mutations and EGFR amplificated were detected in patient-resistant tumor specimens. Although the mutations were not detected in the PDX, EGFR overexpression was observed in RNA sequencing analysis indicating possible off target resistance through the EGFR bypass signaling pathway. Conclusions We established and characterized a pair of METex14 NSCLC patient-derived xenografts (PDXs), including the first crizotinib resistant METex14 PDX. This model will be a powerful tool for testing hypotheses of drug resistance mechanisms and investigations into novel therapeutic strategies.

Case Report: Sequential Combination Targeted Therapy With Type I and II MET Inhibitors in a Metastatic EGFR-Mutated, MET-Amplified NSCLC Patient With Acquired MET Y1230H Mutation

Epidermal growth factor receptor (EGFR) tyrosine kinase inhibitors (TKIs) are the standard of care for advanced non-small-cell lung cancer (NSCLC) patients. However, most patients will eventually develop resistance. For EGFR-TKI resistance mediated by MET amplification, the combination of EGFR and MET TKIs has shown promising results in early clinical trials. However, acquired resistance to MET inhibitors forms a formidable challenge to this dual blockade approach. Here, we presented an NSCLC patient with EGFR exon 19 deletion (ex19del) who was resistant to first-line erlotinib treatment but responded to chemotherapy. Given the finding of MET overexpression/amplification after disease progression, the patient received gefitinib plus crizotinib with a partial response. Her disease progressed again, and molecular testing revealed a novel MET Y1230H mutation and a PD-L1 TPS score of 75%. She received a salvage regime consisting of gefitinib, cabozantinib, and pembrolizumab with a partial response. Since we now know that EGFR ex19del NSCLC patients generally do not respond to PD-1 blockade therapy, this response is more likely the contribution from gefitinib plus cabozantinib. Therefore, sequential use of type I and II MET inhibitors in EGFR/MET dual blockade may be an effective therapeutic option for EGFR-mutant, MET-amplified NSCLC.

Pulmonary Embolism And Bradycardia in a NSCLC Patient Treated With Crizotinib For a Rare Mutation: A Case Report

Lung cancer is a major global health problem because of its high incidence and mortality. Targeted therapies have transformed treatment of driver-mutated metastatic non-small cell lung cancer (NSCLC). Nevertheless, recent studies demonstrated that cardiovascular disease (CVD) was the second leading cause of mortality in cancer survivors now, management of patients’ cardiovascular health during the course of anticancer therapy has become a great challenge faced by the oncologists. Anticancer related CV complications are not limited to traditional chemotherapy, but are also increasingly recognized in targeted therapy. We present a case of pulmonary embolism and bradycardia in a 91-year-old NSCLC patient treated with crizotinib for a rare MET Y1003S mutation. To our knowledge, this is the second report to show antitumor response of crizotinib in lung cancer patients with such a rare mutation. However, the patient complained chest tightness and shortness of breath after a month of standard dose crizotinib therapy. Non-invasive examination revealed new onset bradycardia and pulmonary embolism (PE). Such clinical manifestations were associated with targeted therapy-related cardiovascular（CV）toxicity, on which the emerging discipline cardio-oncology focused, and a multidisciplinary investigation and treatment was conducted. The case highlights the CV adverse events of novel therapies and the current challenges to be tackled in cardio-oncology.

Breaking the Crosstalk of the Cellular Tumorigenic Network in NSCLC by a Highly Effective Drug Combination

Non-small cell lung cancer (NSCLC) is commonly diagnosed at advanced stages limiting treatment options. Although, targeted therapy has become integral part of NSCLC treatment therapies often fail to improve patient`s prognosis. Based on previously published criteria for selecting drug combinations for overcoming resistances, NSCLC patient-derived xenograft (PDX) tumors were treated with a low dose combination of cabozantinib, afatinib, plerixafor and etoricoxib. All PDX tumors treated, including highly therapy-resistant adeno- and squamous cell carcinomas without identifiable driver mutations, were completely suppressed by this drug regimen, leading to an ORR of 81% and a CBR of 100%. The application and safety profile of this low dose therapy regimen was well manageable in the pre-clinical settings. Overall, this study provides evidence of a relationship between active paracrine signaling pathways of the cellular tumorigenic network, which can be effectively targeted by a low-dose multimodal therapy to overcome therapy resistance and improve prognosis of NSCLC.

Quantification of the spatial distribution of primary tumors in the lung to develop new prognostic biomarkers for locally advanced NSCLC

The anatomical location and extent of primary lung tumors have shown prognostic value for overall survival (OS). However, its manual assessment is prone to interobserver variability. This study aims to use data driven identification of image characteristics for OS in locally advanced non-small cell lung cancer (NSCLC) patients. Five stage IIIA/IIIB NSCLC patient cohorts were retrospectively collected. Patients were treated either with radiochemotherapy (RCT): RCT1* (n = 107), RCT2 (n = 95), RCT3 (n = 37) or with surgery combined with radiotherapy or chemotherapy: S1* (n = 135), S2 (n = 55). Based on a deformable image registration (MIM Vista, 6.9.2.), an in-house developed software transferred each primary tumor to the CT scan of a reference patient while maintaining the original tumor shape. A frequency-weighted cumulative status map was created for both exploratory cohorts (indicated with an asterisk), where the spatial extent of the tumor was uni-labeled with 2 years OS. For the exploratory cohorts, a permutation test with random assignment of patient status was performed to identify regions with statistically significant worse OS, referred to as decreased survival areas (DSA). The minimal Euclidean distance between primary tumor to DSA was extracted from the independent cohorts (negative distance in case of overlap). To account for the tumor volume, the distance was scaled with the radius of the volume-equivalent sphere. For the S1 cohort, DSA were located at the right main bronchus whereas for the RCT1 cohort they further extended in cranio-caudal direction. In the independent cohorts, the model based on distance to DSA achieved performance: AUCRCT2 [95% CI] = 0.67 [0.55–0.78] and AUCRCT3 = 0.59 [0.39–0.79] for RCT patients, but showed bad performance for surgery cohort (AUCS2 = 0.52 [0.30–0.74]). Shorter distance to DSA was associated with worse outcome (p = 0.0074). In conclusion, this explanatory analysis quantifies the value of primary tumor location for OS prediction based on cumulative status maps. Shorter distance of primary tumor to a high-risk region was associated with worse prognosis in the RCT cohort.