Case report: Success of tepotinib therapy in overcoming resistance to osimertinib in a patient with EGFR-mutant lung adenocarcinoma with a potential acquired MET exon 14 skipping mutation

Synchronous Double Primary Lung Adenocarcinomas With EGFR L858R Point Mutation and MET Exon 14 Skipping Mutation

Various driver mutations and the corresponding molecular-targeted drugs have been detected and developed in non-small cell lung cancer. There were many cases in which surgical specimens had happened to find double primary cancers. However, to our knowledge, our case was the first report of synchronous double primary lung adenocarcinomas harboring epidermal growth factor receptor (EGFR) L858R and mesenchymal-to-epithelial transition (MET) exon 14 skipping mutations. A 75-year-old Japanese woman with chronic heart and renal failures was referred to our department because of a growing nodule in the right upper lung field on chest X-ray films. Chest computed tomography (CT) detected a nodule in the right S1 and another nodule in the left S1+2. Bronchoscopic biopsy diagnosed the right S1 nodule as moderately differentiated adenocarcinoma. Oncomine Dx Target Test Multi-CDx system of the right S1 adenocarcinoma detected EGFR L858R mutation. The 18F-fluorodeoxyglucose positron emission tomography/CT showed abnormal uptakes both in the right S1 and the left S1+2 nodules, and in the bilateral inferior paratracheal lymph nodes. We made a diagnosis of c-stage IIIA (cT1bN2M0) of adenocarcinoma in the right S1 and suspected another primary lung cancer in the left S1+2. Considering her general conditions, comorbidities and wishes, we started osimertinib. The right S1 cancer achieved partial response (PR), while the left S1+2 nodule and lymph nodes enlarged. Aspiration cytology from the left supraclavicular lymph node showed adenocarcinoma. The FoundationOne® Liquid CDx tumor profiling test detected not only EGFR L858R, but also MET exon 14 skipping mutation. We made a diagnosis of another primary adenocarcinoma from the left S1+2 nodule (cT1bN3M0, c-stage IIIB) with MET mutation, and changed osimertinib to capmatinib. Although the left S1+2 cancer achieved and maintained PR by capmatinib, the right S1 cancer increased, and several new metastases appeared. The subsequent switch from capmatinib to osimertinib could not control cancers. In this case, we tried to switch monotherapies from osimertinib to capmatinib for double primary adenocarcinomas harboring different two driver mutations, according to each cancer progression. The temporal and spatial heterogeneity reinforces the need for primary tissue biopsy if dual primaries are suspected. Temporally distinct liquid biopsies, not standard at present, may be considered.

Unfavorable response to capmatinib for MET exon14 skipping after first-line osimertinib in a patient with EGFR-mutated lung adenocarcinoma: A case report and literature review

MET exon14 skipping mutations (METex14s) are rarely reported as a potential resistance mechanism to EGFR tyrosine kinase inhibitors (TKIs). The efficacy of targeted therapy against METex14s emerging after osimertinib resistance is uncertain. Herein, we report a case of EGFR-mutated metastatic lung adenocarcinoma in which METex14 was detected in a re-biopsy upon first-line osimertinib resistance. The patient received capmatinib monotherapy as third-line therapy, which was ineffective, followed by an exceptional response to salvage therapy with afatinib. This report highlights the heterogeneity of EGFR-TKI resistance and that targeting rare resistance mechanisms remains challenging.

Brief Report: Tepotinib as a Treatment Option in MET Exon 14 Skipping-Positive Lung Cancers-Investigating Discordance Between ArcherMET and the Oncomine Dx Target Test

Introduction

NSCLC is a leading cause of cancer-related mortality worldwide. Specific genetic alterations, such as MET exon 14 (METex14) skipping, have been identified in NSCLC, allowing targeted therapy. Tepotinib, a highly selective MET inhibitor, has displayed promise in patients with advanced NSCLC. Nevertheless, challenges arise when identifying treatment strategies for patients with discordant results regarding METex14 skipping detection between diagnostic tests.

Methods

We investigated patients with NSCLC and discordant results for METex14 skipping between the Oncomine Dx Target Test (ODxTT) and ArcherMET. Clinical response, adverse events, and the duration of tepotinib treatment were assessed, and statistical analysis was performed.

Results

Among the 19 patients deemed METex14 skipping positive by ODxTT, only 10 had concordant results with ArcherMET. The number of METex14 skipping reads detected by ODxTT was significantly lower in discordant cases. Of the 19 patients, 14 received tepotinib, and comparable response and disease control rates were observed in both concordant and discordant cases. The duration of treatment did not significantly differ between the two groups.

Conclusions

Our findings suggest that tepotinib has comparable therapeutic effects in patients with METex14 skipping-positive NSCLC irrespective of the concordance of results between ODxTT and ArcherMET. Tepotinib is a possible treatment option for patients with METex14 skipping, even in patients with discordant test results.

The Efficacy and Safety of Treating Acquired MET Resistance Through Combinations of Parent and MET Tyrosine Kinase Inhibitors in Patients With Metastatic Oncogene-Driven NSCLC

Introduction

Acquired MET gene amplification, MET exon 14 skip mutations, or MET fusions can emerge as resistance mechanisms to tyrosine kinase inhibitors (TKIs) in patients with lung cancer. The efficacy and safety of combining MET TKIs (such as crizotinib, capmatinib, or tepotinib) with parent TKIs to target acquired MET resistance are not well characterized.

Methods

Multi-institutional retrospective chart review identified 83 patients with metastatic oncogene-driven NSCLC that were separated into the following two pairwise matched cohorts: (1) MET cohort (n = 41)-patients with acquired MET resistance continuing their parent TKI with a MET TKI added or (2) Chemotherapy cohort (n = 42)-patients without any actionable resistance continuing their parent TKI with a platinum-pemetrexed added. Clinicopathologic features, radiographic response (by means of Response Evaluation Criteria in Solid Tumors version 1.1), survival outcomes, adverse events (AEs) (by means of Common Terminology Criteria for Adverse Events version 5.0), and genomic data were collected. Survival outcomes were assessed using Kaplan-Meier methods. Multivariate modeling adjusted for lines of therapy, brain metastases, TP53 mutations, and oligometastatic disease.

Results

Within the MET cohort, median age was 56 years (range: 36-83 y). Most patients were never smokers (28 of 41, 68.3%). Baseline brain metastases were common (21 of 41, 51%). The most common oncogenes in the MET cohort were EGFR (30 of 41, 73.2%), ALK (seven of 41, 17.1%), and ROS1 (two of 41, 4.9%). Co-occurring TP53 mutations (32 of 41, 78%) were frequent. Acquired MET alterations included MET gene amplification (37 of 41, 90%), MET exon 14 mutations (two of 41, 5%), and MET gene fusions (two of 41, 5%). After multivariate adjustment, the objective response rate (ORR) was higher in the MET cohort versus the chemotherapy cohort (ORR: 69.2% versus 20%, p < 0.001). Within the MET cohort, MET gene copy number (≥10 versus 6-10) did not affect radiographic response (54.5% versus 68.4%, p = 0.698). There was no difference in ORR on the basis of MET TKI used (F [2, 36] = 0.021, p = 0.978). There was no difference in progression-free survival (5 versus 6 mo; hazard ratio = 0.64; 95% confidence interval: 0.34-1.23, p = 0.18) or overall survival (13 versus 11 mo; hazard ratio = 0.75; 95% confidence interval: 0.42-1.35, p = 0.34) between the MET and chemotherapy cohorts. In the MET cohort, dose reductions for MET TKI-related toxicities were common (17 of 41, 41.4%) but less frequent for parent TKIs (two of 41, 5%). Grade 3 AEs were not significant between crizotinib, capmatinib, and tepotinib (p = 0.3). The discontinuation rate of MET TKIs was 17% with no significant differences between MET TKIs (p = 0.315). Among pre- and post-treatment biopsies (n = 17) in the MET cohort, the most common next-generation sequencing findings were loss of MET gene amplification (15 of 17, 88.2%), MET on-target mutations (seven of 17, 41.2%), new Ras-Raf-MAPK alterations (three of 17, 17.6%), and EGFR gene amplification (two of 17, 11.7%).

Conclusions

The efficacy and safety of combining MET TKIs (crizotinib, capmatinib, or tepotinib) with parent TKIs for acquired MET resistance are efficacious. Radiographic response and AEs did not differ significantly on the basis of the underlying MET TKI used. Loss of MET gene amplification, development of MET on-target mutations, Ras-Raf-MAPK alterations, and EGFR gene amplification were molecular patterns found on progression with dual parent and MET TKI combinations.

Tackling Osimertinib Resistance in EGFR-Mutant Non-Small Cell Lung Cancer

The current landscape of targeted therapies directed against oncogenic driver alterations in non-small cell lung cancer (NSCLC) is expanding. Patients with EGFR-mutant NSCLC can derive significant benefit from EGFR tyrosine kinase inhibitor (TKI) therapy, including the third-generation EGFR TKI osimertinib. However, invariably, all patients will experience disease progression with this therapy mainly due to the adaptation of cancer cells through primary or secondary molecular mechanisms of resistance. The comprehension and access to tissue and cell-free DNA next-generation sequencing have fueled the development of innovative therapeutic strategies to prevent and overcome resistance to osimertinib in the clinical setting. Herein, we review the biological and clinical implications of molecular mechanisms of osimertinib resistance and the ongoing development of therapeutic strategies to overcome or prevent resistance.