Pathologic Complete Response to Neoadjuvant Crizotinib in a Lung Adenocarcinoma Patient With a MET Exon 14 Skipping Mutation

Complete pathological response and negative postoperative ctDNA were not predictive of discontinuation of adjuvant crizotinib therapy in a patient with locally advanced MET ex14 skipping mutation-positive non-small cell lung cancer: a case report

Neoadjuvant targeted therapy is an alternative treatment for locally advanced non-small cell lung cancer (NSCLC) patients with driver gene mutation. MET ex14 mutation is considered a driver gene, and crizotinib is the first oral tyrosine kinase inhibitor (TKI) for metastatic MET ex14 mutation-positive NSCLC patients. Here, we reported a case of a locally advanced NSCLC patient harboring MET ex14 mutation who achieved pathological complete response following neoadjuvant crizotinib therapy but developed rapid metastasis due to discontinuation of short-term postoperative adjuvant crizotinib therapy. Although no driver gene mutation was found via next-generation sequencing (NGS) with blood samples before discontinuation of adjuvant crizotinib, the patient was given crizotinib rechallenge. Fortunately, the patient achieved durable complete response. This suggested that neither pathological complete response nor negative circulating tumor DNA (ctDNA) could be an effective predictor for discontinuation of adjuvant targeted therapy. This case report demonstrated the potential of crizotinib as neoadjuvant therapy in MET ex14 mutation-positive NSCLC patients as well as the importance of long-term postoperative therapy even with negative ctDNA in blood.

Use of savolitinib as neoadjuvant therapy for non-small cell lung cancer patient with MET exon 14 skipping alterations: A case report

Savolitinib is a tyrosine kinase inhibitor being developed for the treatment of metastatic non-small cell lung cancer (NSCLC) with mesenchymal-epithelial transition (MET) factor exon 14 skipping alterations. However, the role of savolitinib in neoadjuvant therapy for lung cancer remains unclear. Here, we present a case of a 65-year-old woman diagnosed with stage IIIA (cT2bN2M0, eighth TNM stage) upper right lung adenocarcinoma harboring MET exon 14 skipping alterations. After 4 weeks of therapy, a partial response was achieved with neoadjuvant savolitinib, and significant shrinkage in tumor and lymph nodes was observed. We also measured the immune microenvironment of the primary tumor pre- and posttreatment with savolitinib.

The safety and feasibility of preoperative induction therapy of Savolitinib in non-small cell lung cancer patients with MET exon 14 skipping mutation

PURPOSE

Neoadjuvant therapy followed by surgical resection is one of the preferred treatment option for locally advanced non-small cell lung cancer (NSCLC). For patients with mesenchymal-epithelial transition (MET) factor exon 14 skipping (METex14) mutations, the use of MET-tyrosine kinase inhibitors (TKIs) showed high efficiency and reduced toxicity compared with first-line standard chemotherapy. However, it is unknown whether preoperative induction targeted therapy of MET-TKIs is feasible and safe.

METHODS

Here, we reported 3 cases of locally advanced unresectable NSCLC with METex14 mutations receiving induction therapy of MET-TKI savolitinib as first-line therapy or second-line therapy when they experienced disease progression after preoperative chemotherapy.

RESULTS

All these 3 patients achieved significant tumor size shrinkage and their unresectable tumors became resectable after the treatment of savolitinib. No serious adverse events were observed during the treatment. They recovered well postoperatively, and no significant events were identified.

CONCLUSIONS

Preoperative induction treatment with MET-TKI savolitinib showed its safety and effectiveness and may be an alternative option for neoadjuvant therapy for NSCLC patients with METex14 mutations.

Neoadjuvant Savolitinib targeted therapy stage IIIA-N2 primary lung adenocarcinoma harboring MET Exon 14 skipping mutation: A case report

MET exon 14 skipping mutation (METex14m) is rare and occurs in approximately 1-4% of all non-small cell lung cancer (NSCLC) patients and approximately 2.8% of resected stage I-III NSCLC patients. Savolitinib is an oral, potent and highly selective type Ib MET inhibitor, which has been shown to be promising activity and acceptable safety profile in patients with advanced NSCLC harboring METex14m. Most recently, many studies have been probing into the feasibility and efficacy of target therapy for perioperative application in NSCLC. Interestingly, there are very few recorded cases of such treatments. Here, we presented that systemic treatment with the MET inhibitor savolitinib before surgery could provide the potential to prolong overall survival (OS) of patients with locally advanced potentially resectable NSCLC. A 49-year-old woman was diagnosed with stage IIIA (T2bN2M0) primary lung adenocarcinoma exhibiting a METex14m by real-time quantitative polymerase chain reaction (RT-qPCR). Given that the tumor load and the size of lymph nodes experienced a significant downstaging after the neoadjuvant treatment of savolitinib with 600mg once a day for 5 weeks, left lower lobectomy and systemic lymphadenectomy were successfully performed. The pathological response was 50% and the final postoperative pathological staging was pT1cN0M0, IA3 (AJCC, 8^th edition). The case provides empirical basis for the neoadjuvant treatment with savolitinib in METex14m-positive locally advanced primary lung adenocarcinoma, which will offer some innovative insights and clinical evidence for more effective clinical treatment of neoadjuvant targeted therapy for METex14m-positive NSCLC.

Management of Non-small Cell Lung Cancer Patients with MET Exon 14 Skipping Mutations

OPINION STATEMENT

The MET exon 14 skipping mutation is found in approximately 3% of lung adenocarcinomas and slightly more than 2% of lung squamous cell carcinomas. In recent years, more and more evidence has shown that MET inhibitors have achieved good anti-tumor effect in patients with MET exon 14 skipping mutation, suggesting that MET exon 14 skipping mutation may be a new target for NSCLC patients. Patients with positive MET exon 14 skipping mutation are recommended to be administered MET inhibitors, and crizotinib is recommended by the NCCN guideline. Due to the presence of gene amplification, second site mutation, bypass activation, and pathological type transformation, one of the inevitable problems of targeted therapy is drug resistance. If type I MET inhibitors (crizotinib, capmatinib, tepotinib, savolitinib) drug resistance is developed, type II MET inhibitors (cabozantinib, glesatinib, merestinib) can be considered.

IASLC Multidisciplinary Recommendations for Pathologic Assessment of Lung Cancer Resection Specimens After Neoadjuvant Therapy

Currently, there is no established guidance on how to process and evaluate resected lung cancer specimens after neoadjuvant therapy in the setting of clinical trials and clinical practice. There is also a lack of precise definitions on the degree of pathologic response, including major pathologic response or complete pathologic response. For other cancers such as osteosarcoma and colorectal, breast, and esophageal carcinomas, there have been multiple studies investigating pathologic assessment of the effects of neoadjuvant therapy, including some detailed recommendations on how to handle these specimens. A comprehensive mapping approach to gross and histologic processing of osteosarcomas after induction therapy has been used for over 40 years. The purpose of this article is to outline detailed recommendations on how to process lung cancer resection specimens and to define pathologic response, including major pathologic response or complete pathologic response after neoadjuvant therapy. A standardized approach is recommended to assess the percentages of (1) viable tumor, (2) necrosis, and (3) stroma (including inflammation and fibrosis) with a total adding up to 100%. This is recommended for all systemic therapies, including chemotherapy, chemoradiation, molecular-targeted therapy, immunotherapy, or any future novel therapies yet to be discovered, whether administered alone or in combination. Specific issues may differ for certain therapies such as immunotherapy, but the grossing process should be similar, and the histologic evaluation should contain these basic elements. Standard pathologic response assessment should allow for comparisons between different therapies and correlations with disease-free survival and overall survival in ongoing and future trials. The International Association for the Study of Lung Cancer has an effort to collect such data from existing and future clinical trials. These recommendations are intended as guidance for clinical trials, although it is hoped they can be viewed as suggestion for good clinical practice outside of clinical trials, to improve consistency of pathologic assessment of treatment response.