UNASSIGNED: The distant metastasis of lung cancer primarily occurs in the bones, liver, brain, and lungs, while the breast is an extremely rare site of metastasis. There is very limited literature on the occurrence of breast metastasis from lung cancer, and metastatic lesions in the breast are prone to being misdiagnosed as primary breast cancer, requiring careful attention and differentiation in the clinical diagnostic and treatment process.
UNASSIGNED: The patient, a 63-year-old female, initially presented with an EGFR exon 21 L858R mutated left lung adenocarcinoma in 2017, treated successfully with surgical resection and subsequent monitoring. The relapse of disease occurred in January 2020. Despite maintaining a prolonged progression-free survival (PFS) with first-generation EGFR-TKI Afatinib, disease progression occurred in 2022 without detectable resistance mutations. Transition to second-generation TKI Furmonertinib resulted in poor control, with rapid progression including unusual bilateral breast metastases that exhibited inflammatory breast cancer-like peau d\'orange changes. Standard chemotherapy achieved only short-term stability. Upon detecting a MET amplification mutation, treatment with Savolitinib was initiated. Remarkably, this led to significant clinical and radiographic improvement, notably resolving the peau d\'orange appearance and reducing multiple lesions across the body.
UNASSIGNED: This case underscores the importance of continuous genetic profiling and tailored treatment approaches in managing advanced lung adenocarcinoma, particularly when presenting with rare metastatic sites and complex genetic landscapes. The successful application of Savolitinib following the identification of a MET amplification mutation highlights its potential in overcoming resistance mechanisms in NSCLC, providing a significant therapeutic option for similarly challenging cases.

Traditionally, the D1228 E/G/H/N mutation has been thought to cause Type I MET-TKI resistance. We reported a 75-year-old female with non-small cell lung cancer harboring MET exon 14 skipping mutation, who developed acquired MET D1228H mutation induced by capmatinib treatment. Interestingly, the patient demonstrated marked response to second-line savolitinib treatment with the duration of response of 19 months and several additional metastatic lesions appeared. Pathological assessment of rebiopsy sample showed adenocarcinoma and targeted next-generation sequencing revealed the loss of MET D1228H mutation and presence of MET p.Y1230N mutation. In response, the treatment regimen was amended to include a daily administration of 60 mg of cabozantinib, which resulted in moderate size reduction of the tumours. The switch of resistance mutations indicated that different type Ib MET inhibitors may exhibit distinct mechanisms of resistance. We call for futher studies on resistance based on patient-derived pre-clinical models including patient-derived tumor-like cell clusters, patient-derived organoids, and patient-derived xenografts.

Dysregulated signaling by mesenchymal epithelial transition factor (MET) and heightened AXL activation are implicated in the pathogenesis of non-small cell lung cancer (NSCLC). Glesatinib (MGCD265) is an investigational, oral inhibitor of MET and AXL.
This open-label, Phase II study investigated glesatinib (free-base suspension [FBS] capsule 1050 mg BID or spray-dried dispersion [SDD] tablet 750 mg BID) in patients with advanced, previously treated NSCLC across four cohorts grouped according to presence of MET activating mutations or amplification in tumor or ctDNA. The primary endpoint was objective response rate (ORR).
Sixty-eight patients were enrolled: n = 28 and n = 8 with MET exon 14 skipping mutations in tumor tissue and ctDNA, respectively, and n = 20 and n = 12 with MET gene amplification in tumor tissue and ctDNA, respectively. Overall, ORR was 11.8 %, median progression-free survival was 4.0 months, and median overall survival was 7.0 months. Among patients with MET activating mutations, ORR was 10.7 % with tumor testing and 25.0 % with ctDNA testing. For MET amplification, responses were observed only in patients enrolled by tumor testing (ORR 15.0 %). Diarrhea (82.4 %), nausea (50.0 %), increased alanine aminotransferase (41.2 %), fatigue (38.2 %), and increased aspartate aminotransferase (36.8 %) were the most frequent adverse events assessed as related to study medication. Glesatinib exposure was similar with the SDD tablet and FBS capsule formulations. The study was terminated early by the sponsor due to modest clinical activity.
Glesatinib had an acceptable safety profile in patients with advanced, pre-treated NSCLC with MET activating alterations. Modest clinical activity was observed, which likely reflects suboptimal drug bioavailability suggested by previously reported Phase I data, and pharmacodynamic findings of lower than anticipated increases in circulating soluble shed MET ectodomain (s-MET).

The mutation of MET plays a crucial role in the initiation of cancer, while the Hedgehog (Hh) pathway also plays a significant role in cell differentiation and the maintenance of tumor stem cells. Conventional chemotherapy drugs are primarily designed to target the majority of cell populations within tumors rather than tumor stem cells. Consequently, after a brief period of remission, tumors often relapse. Moreover, the exclusive targeting of tumor stemness cell disregards the potential for other tumor cells to regain stemness and acquire drug resistance. As a result, current drugs that solely target the HGF/c-MET axis and the Hh pathway demonstrate only moderate efficacy in specific types of cancer. Mounting evidence indicates that these two pathways not only play important roles in cancer but also exert significant influence on the development of resistance to single-target therapies through the secretion of their own ligands. In this comprehensive review, we analyze and compare the potential impact of the Hh pathway on the tumor microenvironment (TME) in HGF/c-MET-driven tumor models, as well as the interplay between different cell types. Additionally, we further substantiate the potential and necessity of dual-pathway combination therapy as a critical target in MET addicted cancer treatment. Video Abstract.

Targeted therapies have revolutionized treatment for metastatic non-small cell lung cancer (NSCLC) with oncogenic driver mutations. However, challenges arise in managing concurrent mutations and overcoming resistance. We present the case of a patient with epidermal growth factor receptor (EGFR) (L747_A750delinsP exon19 deletion) and mesenchymal-epithelial transition factor (MET) mutations (D1228H, D1228N, D1228Y, Y1230H, MET amplification) who achieved a durable response to amivantamab (14 months ongoing) after progression on multiple lines of therapy including platinum-based chemotherapy, EGFR tyrosine kinase inhibitors (TKI) and combination TKI and MET inhibitors. This case highlights the utility of longitudinal next-generation sequencing (NGS) testing to identify acquired resistance and the need for continued research into understanding mechanisms of resistance to help develop future treatment strategies.

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UNASSIGNED: Approximately 3-4% of patients with non-small-cell lung cancer (NSCLC) have MET exon 14 (METex14) skipping mutations. We report primary results from the phase 2 stage of a phase 1b/2 study of gumarontinib, a selective, potent, oral MET inhibitor, in patients with METex14 skipping mutation-positive (METex14-positive) NSCLC.
UNASSIGNED: The single-arm, multicentre, open-label, phase 2 stage of the GLORY study was conducted at 42 centres across China and Japan. Adults with locally advanced or metastatic METex14-positive NSCLC received oral gumarontinib 300 mg once daily in continuous 21-day cycles until disease progression, intolerable toxicity, or withdrawal of consent. Eligible patients had failed one or two prior lines of therapy (not including a MET inhibitor), were ineligible for/refused chemotherapy, and had no genetic alterations targetable with standard therapies. The primary endpoint was objective response rate in patients with a valid baseline tumour assessment, by blinded independent review. The study was registered at ClinicalTrials.gov (NCT04270591).
UNASSIGNED: Between Aug 2, 2019 and Apr 28, 2021, 84 patients were enrolled and received gumarontinib (median follow-up 13.5 months [IQR 8.7-17.1]), at data cut-off (Apr 28, 2022) five patients whose METex14 status could not be confirmed by a central laboratory were excluded from the efficacy analysis. The objective response rate was 66% (95% CI 54-76) overall (n = 79), 71% (95% CI 55-83) in treatment-naïve patients (n = 44), and 60% (95% CI 42-76) in previously-treated patients (n = 35). The most common treatment-related adverse events (any grade) were oedema (67/84 patients, 80%) and hypoalbuminuria (32/84, 38%). Grade ≥3 treatment-emergent adverse events occurred in 45 (54%) patients. Treatment-related adverse events leading to permanent discontinuation occurred in 8% (7/84) of patients.
UNASSIGNED: Gumarontinib monotherapy had durable antitumour activity with manageable toxicity in patients with locally advanced or metastatic METex14-positive NSCLC when used in first line or later.
UNASSIGNED: Haihe Biopharma Co., Ltd. Supported in part by grants from the National Science and Technology Major Project of China for \"Clinical Research of Gumarontinib, a highly selective MET inhibitor\" (2018ZX09711002-011-003); the National Natural Science Foundation of China (82030045 to S.L. and 82172633 to YF.Y); Shanghai Municipal Science & Technology Commission Research Project (19411950500 to S.L.); Shanghai Shenkang Action Plan (16CR3005A to S.L.) and Shanghai Chest Hospital Project of Collaborative Innovation (YJXT20190105 to S.L.).

UNASSIGNED: Aberrant mesenchymal-epithelial transition/hepatocyte growth factor (MET/HGF) regulation presented in a wide variety of human cancers. MET exon 14 skipping, copy number gain (CNG), and kinase domain mutations/arrangements were associated with increased MET activity, and considered to be oncogenic drivers of non-small cell lung cancers (NSCLCs).
UNASSIGNED: We retrospectively analyzed 564 patients with MET alterations. MET alterations were classified into structural mutations or small mutations. MET CNG, exon 14 skipping, gain of function (GOF) mutations, and kinase domain rearrangement were defined as actionable mutations.
UNASSIGNED: Six hundred thirty-two MET mutations were identified including 199 CNG, 117 exon 14 skipping, 12 GOF mutations, and 2 actionable fusions. Higher percentage of MET structural alterations (CNG + fusion) were detected in advanced NSCLC patients. Moreover, MET CNG was enriched while exon 14 skipping was rare in epidermal growth factor receptor-tyrosine kinase inhibitors (EGFR-TKI)-treated advanced NSCLC patients. Ten of the 12 MET GOF mutations were also in EGFR-TKI-treated patients. Fifteen (68.1%) of the 22 patients treated with crizotinib or savolitinib had a partial response. Interestingly, one patient had a great response to savolitinib with a novel MET exon 14 skipping mutation identified after failure of immune-checkpoint inhibitor.
UNASSIGNED: Half of the MET alterations were actionable mutations. MET CNG, exon 14 skipping and GOF mutations had different distribution in different clinical scenario but all defined a molecular subgroup of NSCLCs for which MET inhibition was active.

Targeted therapy has revolutionized the treatment of patients with malignancies harboring mutations in driver genes and has brought a favorable survival benefit to the population with actionable oncogenic mutations. In recent years, the MET exon14 skipping mutation has been recognized as a potentially promising therapeutic target in non-small cell lung cancer (NSCLC). These changes are mutually exclusive with molecular drivers such as EGFR, KRAS, HER-2, BRAF, ALK and ROS1. The prevalence rate of coexisting MET exon 14 mutations and EGFR sensitive mutations (L858R, exon 19 deletions) in Chinese population was reported to be 0.2% (3/1590). However, the coexistence of MET exon 14 mutations with EGFR exon 20 insertion mutations has never been reported and the management of this subtype is not identified.
A 69-year-old male with a right lung adenocarcinoma (T4N2M0, IIIB) was confirmed to be positive for MET exon 14 skipping (c.3028_3028+1delGGinsTT, 44.4%), MET amplification (copy number 4.4), and EGFR exon 20 insertion (p. N771_H773dup, 22.1%) mutations. After the progression of one cycle of chemotherapy (Pemetrexed 0.8 g d1), the patient was subsequently accepted treatment with Crizotinib (250 mg twice a day) and achieved an important clinical remission for six months until the development of brain metastases. Then, he was submitted to a cycle of anti-programmed cell death-1 (PD-1) therapy after failure of Crizotinib and eventually acquired resistance despite of the high expression of programmed death ligand-1 (PD-L1) and tumor mutational burden (TMB) status.
This case report provides treatment strategies for epidermal growth factor receptor tyrosine kinase inhibitors (EGFR-TKIs)-untreated lung adenocarcinoma patients simultaneously carrying MET alterations and EGFR exon 20 insertion mutations. In addition, the signatures of PD-L1 or TMB expression were not the candidate for predicting the efficacy of immunotherapy in this context.

In patients with non-small cell lung cancer (NSCLC) harboring driver alterations, the efficacy of immune checkpoint inhibitors (ICIs) remains uncertain. Our study aimed to examine the first-line ICI efficacy in patients with NSCLC harboring KRAS, MET, FGFR, RET, BRAF, and HER2 alterations in a real-world setting.
This single-center, retrospective cohort study included patients with advanced NSCLC harboring KRAS, MET, FGFR, RET, BRAF, HER2 alterations or driver-negative, and were treated with first-line ICI therapy. Best overall response, progression-free survival (PFS), and overall survival (OS) were evaluated.
Seventy-eight patients with NSCLC were included (median age, 72 years): 67% were men, 15% were never-smokers, and 83% had adenocarcinoma. The driver alterations involved KRAS (n = 21), MET (n = 6), FGFR (n = 3), RET (n = 2), BRAF (n = 2), HER2 (n = 1), and driver-negative (n = 43). The partial responses for KRAS, MET, FGFR, RET, BRAF, HER2, and driver-negative were 57%, 50%, 100%, 50%, 100%, 0%, and 47%, respectively. The median PFS (months) was 16.2 (95% confidence interval [CI]: 6.3- not reached [NR]) for KRAS, 2.8 (95% CI: 2.7-NR) for MET, 11.7 (95% CI: 5.9-NR) for other alterations (FGFR, RET, BRAF, and HER2), and 10.0 (95% CI: 3.7-14.3) for driver-negative, respectively. The median OS (months) was 31.3 (95% CI: 9.0-NR) for KRAS, not reached for MET, 23.5 (95% CI: 18.3-NR) for other alterations, and 21.1 (95% CI: 15.2-NR) for driver-negative, respectively.
The benefit of the first-line ICI was similar in advanced NSCLC regardless of the driver alterations, except for MET alterations.