MET Alterations Are a Recurring and Actionable Resistance Mechanism in ALK-Positive Lung Cancer

Mechanisms of resistance to tyrosine kinase inhibitor-targeted therapy and overcoming strategies

Tyrosine kinase inhibitor (TKI)-targeted therapy has revolutionized cancer treatment by selectively blocking specific signaling pathways crucial for tumor growth, offering improved outcomes with fewer side effects compared with conventional chemotherapy. However, despite their initial effectiveness, resistance to TKIs remains a significant challenge in clinical practice. Understanding the mechanisms underlying TKI resistance is paramount for improving patient outcomes and developing more effective treatment strategies. In this review, we explored various mechanisms contributing to TKI resistance, including on-target mechanisms and off-target mechanisms, as well as changes in the tumor histology and tumor microenvironment (intrinsic mechanisms). Additionally, we summarized current therapeutic approaches aiming at circumventing TKI resistance, including the development of next-generation TKIs and combination therapies. We also discussed emerging strategies such as the use of dual-targeted antibodies and PROteolysis Targeting Chimeras. Furthermore, we explored future directions in TKI-targeted therapy, including the methods for detecting and monitoring drug resistance during treatment, identification of novel targets, exploration of dual-acting kinase inhibitors, application of nanotechnologies in targeted therapy, and so on. Overall, this review provides a comprehensive overview of the challenges and opportunities in TKI-targeted therapy, aiming to advance our understanding of resistance mechanisms and guide the development of more effective therapeutic approaches in cancer treatment.

Targeting ALK receptors in non-small cell lung cancer: what is the road ahead?

INTRODUCTION

Anaplastic lymphoma kinase (ALK) gene-rearrangements are identified in about 3-5% of non-small cell lung cancers (NSCLC), and ALK-rearranged NSCLC is to be considered an oncogene-addicted cancer with peculiar clinical characteristics.

AREAS COVERED

Several ALK inhibitors have been studied and approved for use in the treatment of advanced ALK-rearranged NSCLC with reported superiority in terms of efficacy and safety profile compared with chemotherapy. Second- and third-generation ALK inhibitors (alectinib, brigatinib, and lorlatinib) offer to NSCLC patients a clinically meaningful prolongment of survival with a very good quality of life profile. However, resistances to these agents always occur, with less satisfying options for second-line treatments. Direct comparisons among these agents are not available, and the choice among brigatinib, alectinib, and lorlatinib as first-line treatment remains challenging. Very recently, alectinib has been demonstrated to improve efficacy outcomes compared with chemotherapy also in resected stage IB-IIIA ALK-rearranged NSCLC, extending the clinical benefit offered by ALK inhibitors also to the adjuvant setting.

EXPERT OPINION

Future development of ALK inhibitors in NSCLC treatment includes the search for optimal management of acquired resistance to first-line treatments and the extension of use of ALK inhibitors also to neoadjuvant and preferably to perioperative setting.

Understanding the treatment response and resistance to targeted therapies in non-small cell lung cancer: clinical insights and perspectives

Lung cancer remains the leading cause of mortality worldwide. Non-small cell lung cancer (NSCLC) is the most common subtype of lung cancer with a generally poor prognosis. In recent years, advances in targeted therapy and sequencing technology have brought significant improvement in the therapeutic outcomes of patients with advanced NSCLC. Targeted inhibitors directed against specific mutated or rearranged oncogenes, such as epidermal growth factor receptor (EGFR), anaplastic lymphoma kinase (ALK), and receptor tyrosine kinase ROS proto-oncogene 1(ROS1) among others, exhibit promising anti-tumor activity. Unfortunately, some patients develop acquired resistance and disease progression soon after initial remission. Despite the continuous development of new drugs and strategies to overcome drug resistance, it is still a major challenge in the treatment of NSCLC. The landscape of targeted therapy for NSCLC is evolving rapidly in response to the pace of scientific research. This study aimed to provide a comprehensive review of tumor target antigens and agents related to targeted therapy in NSCLC.

IC Regimen: Delaying Resistance to Lorlatinib in ALK Driven Cancers by Adding Repurposed Itraconazole and Cilostazol

Lorlatinib is a pharmaceutical ALK kinase inhibitor used to treat ALK driven non-small cell lung cancers. This paper analyses the intersection of past published data on the physiological consequences of two unrelated drugs from general medical practice-itraconazole and cilostazol-with the pathophysiology of ALK positive non-small cell lung cancer. A conclusion from that data analysis is that adding itraconazole and cilostazol may make lorlatinib more effective. Itraconazole, although marketed worldwide as a generic antifungal drug, also inhibits Hedgehog signaling, Wnt signaling, hepatic CYP3A4, and the p-gp efflux pump. Cilostazol, marketed worldwide as a generic thrombosis preventative drug, acts by inhibiting phosphodiesterase 3, and, by so doing, lowers platelets' adhesion, thereby partially depriving malignant cells of the many tumor trophic growth factors supplied by platelets. Itraconazole may enhance lorlatinib effectiveness by (i) reducing or stopping a Hedgehog-ALK amplifying feedback loop, by (ii) increasing lorlatinib's brain levels by p-gp inhibition, and by (iii) inhibiting growth drive from Wnt signaling. Cilostazol, surprisingly, carries minimal bleeding risk, lower than that of aspirin. Risk/benefit assessment of the combination of metastatic ALK positive lung cancer being a low-survival disease with the predicted safety of itraconazole-cilostazol augmentation of lorlatinib favors a trial of this drug trio in ALK positive lung cancer.

Navigating resistance to ALK inhibitors in the lorlatinib era: a comprehensive perspective on NSCLC

INTRODUCTION

The emergence of anaplastic lymphoma kinase (ALK) rearrangements in non-small cell lung cancer (NSCLC) has revolutionized targeted therapy. This dynamic landscape, featuring novel ALK inhibitors and combination therapies, necessitates a profound understanding of resistance mechanisms for effective treatment strategies. Recognizing two primary categories - on-target and off-target resistance - underscores the need for comprehensive assessment.

AREAS COVERED

This review delves into the intricacies of resistance to ALK inhibitors, exploring complexities in identification and management. Molecular testing, pivotal for early detection and accurate diagnosis, forms the foundation for patient stratification and resistance management. The literature search methodology involved comprehensive exploration of Pubmed and Embase. The multifaceted perspective encompasses new therapeutic horizons, ongoing clinical trials, and their clinical implications post the recent approval of lorlatinib.

EXPERT OPINION

Our expert opinion encapsulates the critical importance of understanding resistance mechanisms in the context of ALK inhibitors for shaping successful treatment approaches. With a focus on molecular testing and comprehensive assessment, this review contributes valuable insights to the evolving landscape of NSCLC therapy.

ALK inhibitors in cancer: mechanisms of resistance and therapeutic management strategies

Anaplastic lymphoma kinase (ALK) gene rearrangements have been identified as potent oncogenic drivers in several malignancies, including non-small cell lung cancer (NSCLC). The discovery of ALK inhibition using a tyrosine kinase inhibitor (TKI) has dramatically improved the outcomes of patients with ALK-mutated NSCLC. However, the emergence of intrinsic and acquired resistance inevitably occurs with ALK TKI use. This review describes the molecular mechanisms of ALK TKI resistance and discusses management strategies to overcome therapeutic resistance.

TWIST1 is a critical downstream target of the HGF/MET pathway and is required for MET driven acquired resistance in oncogene driven lung cancer

MET amplification/mutations are important targetable oncogenic drivers in NSCLC, however, acquired resistance is inevitable and the majority of patients with targetable MET alterations fail to respond to MET tyrosine kinase inhibitors (TKIs). Furthermore, MET amplification is among the most common mediators of TKI resistance. As such, novel therapies to target MET pathway and overcome MET TKI resistance are clearly needed. Here we show that the epithelial-mesenchymal transition (EMT) transcription factor, TWIST1 is a key downstream mediator of HGF/MET induced resistance through suppression of p27 and targeting TWIST1 can overcome resistance. We found that TWIST1 is overexpressed at the time of TKI resistance in multiple MET-dependent TKI acquired resistance PDX models. We have shown for the first time that MET directly stabilized the TWIST protein leading to TKI resistance and that TWIST1 was required for MET-driven lung tumorigenesis as well as could induce MET TKI resistance when overexpressed. TWIST1 mediated MET TKI resistance through suppression of p27 expression and genetic or pharmacologic inhibition of TWIST1 overcame TKI resistance in vitro and in vivo. Our findings suggest that targeting TWIST1 may be an effective therapeutic strategy to overcome resistance in MET-driven NSCLC as well as in other oncogene driven subtypes in which MET amplification is the resistance mechanism.

Response to capmatinib in a patient with neuroendocrine carcinoma of the gallbladder origin harboring MET amplification

Neuroendocrine carcinoma (NEC) of the gallbladder origin is particularly rare, accounting for only 0.38% of primary malignancies of the gallbladder, and standard therapies are limited. The MET gene encodes the tyrosine kinase receptor, c-Met. Pathogenic variants of MET, such as MET exon 14 skipping and MET amplification, result in excessive downstream signaling that promotes tumor progression. A MET inhibitor, capmatinib, blocks signaling of c-Met and has been approved by the Food and Drug Administration for non-small cell lung cancer with MET exon 14 skipping. The effectiveness of capmatinib has been reported in other cancers with MET amplification, but NEC with MET variants has not been reported. Here, we present a case of a 72-year-old woman with NEC of the gallbladder with multiple liver and lymph node metastases, who was resistant to conventional chemotherapy including carboplatin plus etoposide as first-line treatment and irinotecan as second-line treatment, but she responded to capmatinib. After 6 weeks of treatment, CT scan showed a partial response (80% reduction in size), but after 13 weeks, regrowth of liver metastasis was observed. Herein, we report a meaningful efficacy of capmatinib to the patient of NEC of the gallbladder origin with MET amplification.

The MET Oncogene: Thirty Years of Insights into Molecular Mechanisms Driving Malignancy

The discovery and subsequent research on the MET oncogene's role in cancer onset and progression have illuminated crucial insights into the molecular mechanisms driving malignancy. The identification of MET as the hepatocyte growth factor (HGF) receptor has paved the path for characterizing the MET tyrosine kinase activation mechanism and its downstream signaling cascade. Over the past thirty years, research has established the importance of HGF/MET signaling in normal cellular processes, such as cell dissociation, migration, proliferation, and cell survival. Notably, genetic alterations that lead to the continuous activation of MET, known as constitutive activation, have been identified as oncogenic drivers in various cancers. The genetic lesions affecting MET, such as exon skipping, gene amplification, and gene rearrangements, provide valuable targets for therapeutic intervention. Moreover, the implications of MET as a resistance mechanism to targeted therapies emphasize the need for combination treatments that include MET inhibitors. The intriguing "flare effect" phenomenon, wherein MET inhibition can lead to post-treatment increases in cancer cell proliferation, underscores the dynamic nature of cancer therapeutics. In human tumors, increased protein expression often occurs without gene amplification. Various mechanisms may cause an overexpression: transcriptional upregulation induced by other oncogenes; environmental factors (such as hypoxia or radiation); or substances produced by the reactive stroma, such as inflammatory cytokines, pro-angiogenic factors, and even HGF itself. In conclusion, the journey to understanding MET's involvement in cancer onset and progression over the past three decades has not only deepened our knowledge, but has also paved the way for innovative therapeutic strategies. Selective pharmacological inactivation of MET stands as a promising avenue for achieving cancer remission, particularly in cases where MET alterations are the primary drivers of malignancy.

Deterministic reprogramming and signaling activation following targeted therapy in non-small cell lung cancer driven by mutations or oncogenic fusions

INTRODUCTION

Targeted therapy is used to treat lung adenocarcinoma caused by epidermal growth factor receptor (EGFR) mutations in the tyrosine kinase domain and rare subtypes (<5%) of non-small cell lung cancer. These subtypes include fusion oncoproteins like anaplastic lymphoma kinase (ALK), ROS1, rearranged during transfection (RET), and other receptor tyrosine kinases (RTKs). The use of diverse selective oral inhibitors, including those targeting rat sarcoma viral oncogene homolog (KRAS) mutations, has significantly improved clinical responses, extending progression-free and overall survival.

AREAS COVERED

Resistance remains a critical issue in lung adenocarcinoma, notably in EGFR mutant, echinoderm microtubule associated protein-like 4 (EML4)-ALK fusion, and KRAS mutant tumors, often associated with epithelial-to-mesenchymal transition (EMT).

EXPERT OPINION

Despite advancements in next generation EGFR inhibitors and EML4-ALK therapies with enhanced brain penetrance and identifying resistance mutations, overcoming resistance has not been abated. Various strategies are being explored to overcome this issue to achieve prolonged cancer remission and delay resistance. Targeting yes-associated protein (YAP) and the mechanisms associated with YAP activation through Hippo-dependent or independent pathways, is desirable. Additionally, the exploration of liquid-liquid phase separation in fusion oncoproteins forming condensates in the cytoplasm for oncogenic signaling is a promising field for the development of new treatments.

Prognostic and predictive biomarkers in non-small cell lung carcinoma

Lung cancer is the most common cause of cancer-related deaths globally, with the highest mortality rates among both men and women. Most lung cancers are diagnosed at late stages, necessitating systemic therapy. Modern clinical management of lung cancer relies heavily upon application of biomarkers, which guide the selection of systemic treatment. Here, we provide an overview of currently approved and emerging biomarkers of non-small cell lung cancer (NSCLC), including EGFR, ALK, ROS1, RET, NTRK1-3, KRAS, BRAF, MET, ERBB2/HER2, NRG1, PD-L1, TROP2, and CEACAM5. For practical purposes, we divide these biomarkers into genomic and protein markers, based on the tested substrate. We review the biology and epidemiology of the genomic and proteomic biomarkers, discuss optimal diagnostic assays for their detection, and highlight their contribution to the contemporary clinical management of NSCLC.

Ensartinib is effective in the treatment of advanced non-small-cell lung cancer with MET amplification after multi-line ALK-TKIs resistance: a case report

Although patients with ALK-positive non-small cell lung cancer (NSCLC) are initially effective on treatment with ALK tyrosine kinase inhibitors (TKIs), resistance will inevitably develop. Of these patients, 2/3 will develop ALK-independent resistance and little is known about the mechanisms of ALK-independent resistance. In pre-clinical studies, the activation of several bypass signaling pathways has been implicated in the development of resistance, including the MET, EGFR, SRC and IGF1R pathways. Among these, the MET pathway is one of the signaling pathways that has recently been extensively studied, and activation of this pathway is one of the mechanisms of ALK-independent drug resistance. Here, we report a successful case of an advanced NSCLC patient who was resistant to treatment with ALK TKIs and developed MET amplification, who achieved 23 months of progression-free survival after post-line treatment with ensartinib.

HER3 overexpression: a predictive marker for poor prognosis in advanced ALK-positive non-small cell lung cancer treated with ALK inhibitors

Background

Anaplastic lymphoma kinase (ALK)-targeted tyrosine kinase inhibitors (TKIs) improve patient survival; however, some patients develop ALK-TKI resistance with unidentified mechanisms. We investigated ErbB family and c-MET expression in patients with ALK-positive non-small cell lung cancer (NSCLC) to understand their roles in the ALK-TKI response.

Methods

We studied 72 patients with advanced ALK-positive NSCLC with EML4-ALK fusion variant subtyping and immunostaining for c-MET, EGFR, HER2, and HER3 on tissue specimens both pre- (primary) and post-treatment (secondary) with ALK-TKI. We investigated the association of their expression with survival outcomes and assessed the effectiveness of combining ALK and EGFR inhibitors in ALK-positive NSCLC cell lines stimulated with the HER3-specific ligand HRG1.

Results

High expression of c-MET, EGFR, HER2, and HER3 was observed in 4.9%, 18.0%, 1.6%, and 25.8% of primary tumors, respectively, and 18.5%, 37.0%, 10.7%, and 35.7% of secondary tumors, respectively. HER3 overexpression in primary tumors showed inferior survival (P=0.132). In the subgroup with EML4-ALK variant 1/2 (V1/V2), HER3 overexpression was significantly associated with inferior survival in both primary and secondary tumors (P=0.022 and P=0.004, respectively). Combination treatment with lorlatinib and erlotinib significantly reduced HRG1-induced activation of RTK signaling in ALK-positive NSCLC cells.

Conclusions

HER3 overexpression has potential as a prognostic marker in ALK-positive NSCLCs, including ALK-TKI naïve and treated cases, especially those with EML4-ALK V1/V2. Assessing HER3 expression may be crucial for treatment planning and outcome prediction in these patients.

Overcoming Central β-Sheet #6 (Cβ6) ALK Mutation (L1256F), TP53 Mutations and Short Forms of EML4-ALK v3/b and v5a/b Splice Variants are the Unmet Need That a Re-Imagined 5th-Generation (5G) ALK TKI Must Deliver

Despite the development and approval of seven anaplastic lymphoma kinase (ALK) tyrosine kinase inhibitors (TKIs) spanning over three "generations" since the discovery of ALK fusion positive (ALK+) non-small cell lung cancer (NSCLC), there remains intrinsic and acquired resistances to these approved TKIs. Currently, a fourth-generation (4G) ALK TKI, NVL-655, is being developed to attack some of the unmet needs such as compound resistance mutations in cis. However, EML4-ALK variant 3 and TP53 mutations are intrinsic genomic alterations that negatively modulate efficacy of ALK TKIs. Potentially, in the shifting landscape where lorlatinib should be the first-line ALK TKI of choice based on the CROWN trial, the central β-sheet #6 (Cβ6) mutation ALK L1256F will be the potential acquired resistance mutation to lorlatinib which may be resistant to current ALK TKIs. Here we opine on what additional capacities a putative fifth-generation (5G) ALK TKI will need to possess if it can be achieved in one single molecule. We propose randomized trial schemas targeting some of the intrinsic resistance mechanisms that will lead to approval of a prototypic fifth-generation (5G) ALK TKI and actually be beneficial to ALK+ NSCLC patients rather than just design a positive pivotal superiority trial for the sole purpose of drug approval.

Real world study of safety and efficacy of lorlatinib as second line and beyond in ALK-rearranged advanced non-small cell lung cancer patients in India - a multicentre chart review study (ROSELAND)

Background

Lorlatinib, an anaplastic lymphoma kinase (ALK)-inhibitor, is approved as frontline as well as subsequent line of therapy in ALK-rearranged advanced non-small cell lung cancer (NSCLC). There is limited literature about safety and efficacy of lorlatinib in Indian patients.

Materials and methods

This was a retrospective multicentre study on patients with ALK-rearranged advanced NSCLC received lorlatinib as second line and beyond between May 2017 and December 2021. ALK was tested either by immunohistochemistry or fluorescent in-situ hybridisation. Clinicopathologic features, treatment details, toxicity and outcomes were analysed.

Results

A total of 38 patients were enrolled with a median age of 54 years (range: 30-72) and male: female ratio of 20:18. Fifteen (44%) patients had brain metastases at baseline. Lorlatinib use was - second line in 11 (29%), third line in 21 (55%) and fourth line in 4 (11%) of patients, respectively. The best radiologic response to lorlatinib was - complete response in 9 (24%), partial response in 17 (46%), stable disease in 9 (24%) and progressive disease in 2 (5%) of patients, respectively. After a median follow-up of 76.6 months (95% CI: 68.9-100), the median progression-free survival (PFS) of lorlatinib was not reached (95% CI: 24.3-not reached) and median overall survival (OS) of the whole cohort was 93.1 months (95% CI: 62-not reached). Both median PFS (p = 0.48) and median OS (p = 0.74) was similar between second line and later line use of lorlatinib. Thirty-three (87%) patients experienced treatment-related toxicity and six (16%) patients required dose modification.

Conclusion

Lorlatinib was highly efficacious in terms of overall response rate, median PFS and median OS in this small real-world cohort of advanced ALK+ve NSCLC with a manageable safety profile.

Lung cancer in patients who have never smoked - an emerging disease

Lung cancer is the most common cause of cancer-related deaths globally. Although smoking-related lung cancers continue to account for the majority of diagnoses, smoking rates have been decreasing for several decades. Lung cancer in individuals who have never smoked (LCINS) is estimated to be the fifth most common cause of cancer-related deaths worldwide in 2023, preferentially occurring in women and Asian populations. As smoking rates continue to decline, understanding the aetiology and features of this disease, which necessitate unique diagnostic and treatment paradigms, will be imperative. New data have provided important insights into the molecular and genomic characteristics of LCINS, which are distinct from those of smoking-associated lung cancers and directly affect treatment decisions and outcomes. Herein, we review the emerging data regarding the aetiology and features of LCINS, particularly the genetic and environmental underpinnings of this disease as well as their implications for treatment. In addition, we outline the unique diagnostic and therapeutic paradigms of LCINS and discuss future directions in identifying individuals at high risk of this disease for potential screening efforts.

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.

Translation into Clinical Practice of the G1-G7 Molecular Subgroup Classification of Glioblastoma: Comprehensive Demographic and Molecular Pathway Profiling

Glioblastoma is the most frequent and malignant primary neoplasm of the central nervous system. In a recent breakthrough study on a prospective Discovery cohort, I proposed the first all-inclusive molecular classification of glioblastoma into seven subgroups, G1-G7, based on MAPK pathway activation. New data from a WHO-grade-4 diffuse glioma prospective Validation cohort offers, in this study, an integrated demographic-molecular analysis of a 213-patient Combined cohort. Despite cohort differences in the median age and molecular subgroup distribution, all the prospectively-acquired cases from the Validation cohort mapped into one of the G1-G7 subgroups defined in the Discovery cohort. A younger age of onset, higher tumor mutation burden and expanded G1/EGFR-mutant and G3/NF1 glioblastoma subgroups characterized the glioblastomas from African American/Black relative to Caucasian/White patients. The three largest molecular subgroups were G1/EGFR, G3/NF1 and G7/Other. The fourth largest subgroup, G6/Multi-RTK, was detailed by describing a novel gene fusion ST7-MET, rare PTPRZ1-MET, LMNA-NTRK1 and GOPC-ROS1 fusions and their overexpression mechanisms in glioblastoma. The correlations between the MAPK pathway G1-G7 subgroups and the PI3-kinase/PTEN, TERT, cell cycle G1 phase and p53 pathways defined characteristic subgroup pathway profiles amenable to personalized targeted therapy. This analysis validated the first all-inclusive molecular classification of glioblastoma, showed significant demographic and molecular differences between subgroups, and provided the first ethnic molecular comparison of glioblastoma.

Interstitial pneumonia disease induced by osimertinib combined with savolitinib targeted therapy in a lung cancer patient: A case report

RATIONALE

MET-TKI is a late-stage treatment for drug-resistant NSCLC that has been marketed in recent years, and interstitial lung disease may be a rare adverse reaction. This case reports the development of interstitial lung disease in a patient with advanced lung cancer who developed during treatment with savolitinib after resistance to osimertinib.

PATIENT CONCERNS

A 74-year-old female diagnosed with lung adenocarcinoma was referred to our hospital with chest tightness and shortness of breath following treatment with osimertinib plus savolitinib.

DIAGNOSE

Chest CT of the patient shows interstitial changes in both lungs, and drug-related interstitial lung disease is considered in the context of the patient previous condition.

INTERVENTIONS

The patient is treated with methods such as glucocorticoids, anti-infection, and mechanical ventilation.

OUTCOMES

At the 1-year follow-up visit, the patient condition of interstitial lung disease was relatively stable. The patient has passed away due to tumor progression.

LESSONS

This case reported interstitial lung disease following osimertinib plus savolitinib. This suggests that healthcare providers should be aware of early symptoms of interstitial lung disease during treatment and treat them appropriately to prevent symptoms from worsening.

Chinese expert consensus on clinical practice of MET detection in non-small cell lung cancer

Mesenchymal epithelial transition (MET) factor alteration in non-small cell lung cancer (NSCLC) includes MET exon 14 skipping alteration (METex14 skipping), MET gene amplification, MET gene mutation (mainly kinase domain mutation), MET gene fusion, and MET protein overexpression. The incidence of METex14 skipping in patients with NSCLC is 0.9-4.0%. At present, drugs targeting METex14 skipping have been approved in China and other countries like Japan and USA. Patients with advanced NSCLC should undergo testing, including METex14 skipping, to screen the population with benefit from targeted therapy with MET inhibitors. The incidence of de novo MET gene amplification in NSCLC patients is 1-5%, the incidence of acquired MET gene amplification in epidermal growth factor receptor tyrosine kinase inhibitor (TKI)-resistant patients is 5-50%, and the incidence in anaplastic lymphoma kinase (ALK) TKI-resistant patients is about 13%; the incidence of MET protein overexpression in NSCLC patients is 13.7-63.7%. Several clinical trials on MET gene amplification and MET protein overexpression are ongoing, which have demonstrated their important guiding significance as biomarkers in the clinical treatment with MET inhibitors. Accurate detection of MET alterations is a prerequisite for MET inhibitor therapy. Since there are many types of MET alterations and related testing methods, as well as many problems and challenges during clinical testing, further sorting and standardization are required. Combined with clinical practice experience, literature review, and expert discussion, the writing group developed this consensus on the three main types of MET alterations (METex14 skipping, MET gene amplification, and MET protein overexpression) in order to guide the practical applications of clinical MET testing.

MIG6 Mediates Adaptive and Acquired Resistance to ALK/ROS1 Fusion Kinase Inhibition through EGFR Bypass Signaling

Despite the initial benefit from tyrosine kinase inhibitors (TKI) targeting oncogenic ALK and ROS1 gene fusions in non-small cell lung cancer, complete responses are rare and resistance ultimately emerges from residual tumor cells. Although several acquired resistance mechanisms have been reported at the time of disease progression, adaptative resistance mechanisms that contribute to residual diseases before the outgrowth of tumor cells with acquired resistance are less clear. For the patients who have progressed after TKI treatments, but do not demonstrate ALK/ROS1 kinase mutations, there is a lack of biomarkers to guide effective treatments. Herein, we found that phosphorylation of MIG6, encoded by the ERRFI1 gene, was downregulated by ALK/ROS1 inhibitors as were mRNA levels, thus potentiating EGFR activity to support cell survival as an adaptive resistance mechanism. MIG6 downregulation was sustained following chronic exposure to ALK/ROS1 inhibitors to support the establishment of acquired resistance. A higher ratio of EGFR to MIG6 expression was found in ALK TKI-treated and ALK TKI-resistant tumors and correlated with the poor responsiveness to ALK/ROS1 inhibition in patient-derived cell lines. Furthermore, we identified and validated a MIG6 EGFR-binding domain truncation mutation in mediating resistance to ROS1 inhibitors but sensitivity to EGFR inhibitors. A MIG6 deletion was also found in a patient after progressing to ROS1 inhibition. Collectively, this study identifies MIG6 as a novel regulator for EGFR-mediated adaptive and acquired resistance to ALK/ROS1 inhibitors and suggests EGFR to MIG6 ratios and MIG6-damaging alterations as biomarkers to predict responsiveness to ALK/ROS1 and EGFR inhibitors.

MET Fusions in NSCLC: Clinicopathologic Features and Response to MET Inhibition

INTRODUCTION

MET fusions have been described only rarely in NSCLC. Thus, data on patient characteristics and treatment response are limited. We here report histopathologic data, patient demographics, and treatment outcome including response to MET tyrosine kinase inhibitor (TKI) therapy in MET fusion-positive NSCLC.

METHODS

Patients with NSCLC and MET fusions were identified mostly by RNA sequencing within the routine molecular screening program of the national Network Genomic Medicine, Germany.

RESULTS

We describe a cohort of nine patients harboring MET fusions. Among these nine patients, two patients had been reported earlier. The overall frequency was 0.29% (95% confidence interval: 0.15-0.55). The tumors were exclusively adenocarcinoma. The cohort was heterogeneous in terms of age, sex, or smoking status. We saw five different fusion partner genes (KIF5B, TRIM4, ST7, PRKAR2B, and CAPZA2) and several different breakpoints. Four patients were treated with a MET TKI leading to two partial responses, one stable disease, and one progressive disease. One patient had a BRAF V600E mutation as acquired resistance mechanism.

CONCLUSIONS

MET fusions are very rare oncogenic driver events in NSCLC and predominantly seem in adenocarcinomas. They are heterogeneous in terms of fusion partners and breakpoints. Patients with MET fusion can benefit from MET TKI therapy.

An advanced NSCLC patient with ALK-RNF144A and HIP1-ALK fusions treated with ALK-TKI combination therapy: a case report

Background

Anaplastic lymphoma kinase (ALK) rearrangement is one of the most important drivers in non-small cell lung cancer (NSCLC). Despite the effectiveness to canonical 3'-ALK fusions, the clinical efficacy of ALK inhibitors in patients with complex ALK fusions, such as nonreciprocal/reciprocal translocation remains uncertain. Exploring the optimal therapeutic regimens for this subset of patients is of crucial clinical significance.

Case Description

We reported a female patient diagnosed with stage IVB lung adenocarcinoma (LUAD) harboring a novel ALK-RNF144A fusion, concurrent with a Huntingtin-interacting protein 1 (HIP1)-ALK fusion and a RB1 loss-of-function variant. The patient sequentially received multiple lines of treatment with ALK-tyrosine kinase inhibitor (TKI), chemotherapy, radiotherapy and ALK-TKI combined with anti-angiogenesis. Disease progression accompanied by a squamous cell carcinoma transformation was indicated after ALK-TKI combined with anti-angiogenesis and both ALK-RNF144A and HIP1-ALK fusions were retained in the tumor. The patient was subsequently treated with a third generation ALK-TKI, lorlatinib, in combination with albumin-bound paclitaxel and anlotinib, and then achieved stable disease. The patient remained on the treatment as of the last follow-up resulting in an overall survival (OS) of more than 18 months.

Conclusions

We have reported an advanced NSCLC patient with a complex nonreciprocal/reciprocal ALK translocation containing a novel ALK-RNF144A fusion, concurrent with a RB1 loss-of-function mutation, who subsequently experienced pathological squamous cell carcinoma transformation. The combined treatment with ALK-TKI, chemotherapy, and anti-angiogenesis demonstrates clinical efficacy and may provide optional therapeutic strategies for this phenotype.

From Development to Place in Therapy of Lorlatinib for the Treatment of ALK and ROS1 Rearranged Non-Small Cell Lung Cancer (NSCLC)

Following the results of the CROWN phase III trial, the third-generation macrocyclic ALK inhibitor lorlatinib has been introduced as a salvage option after the failure of a first-line TKI in ALK-rearranged NSCLC, while its precise role in the therapeutic algorithm of ROS1 positive disease is still to be completely defined. The ability to overcome acquired resistance to prior generation TKIs (alectinib, brigatinib, ceritinib, and crizotinib) and the high intracranial activity in brain metastatic disease thanks to increased blood-brain barrier penetration are the reasons for the growing popularity and interest in this molecule. Nevertheless, the major vulnerability of this drug resides in a peculiar profile of related collateral events, with neurological impairment being the most conflicting and debated clinical issue. The cognitive safety concern, the susceptibility to heterogeneous resistance pathways, and the absence of a valid alternative in the second line are strongly jeopardizing a potential paradigm shift in this oncogene-addicted disease. So, when prescribing lorlatinib, clinicians must face two diametrically opposed characteristics: a great therapeutic potential without the intrinsic limitations of its precursor TKIs, a cytotoxic activity threatened by suboptimal tolerability, and the unavoidable onset of resistance mechanisms we cannot properly manage yet. In this paper, we give a critical point of view on the stepwise introduction of this promising drug into clinical practice, starting from its innovative molecular and biochemical properties to intriguing future developments, without forgetting its weaknesses.

Management strategies for intracranial progression in ALK-positive non-small cell lung cancer: a real-world cohort study

PURPOSE

ALK-positive NSCLC patients exhibit a particularly high propensity for the development of brain metastases. Current guidelines suggest transit to next-line therapy (SysTx) or local radiotherapy (RadTx) including whole-brain radiotherapy and radiosurgery. However, the clinical impact of these two strategies remains unclear.

METHODS

We conducted a retrospective analysis focusing on patients with stage IV ALK-positive NSCLC who underwent first-line ALK TKI treatment. Patients with intracranial progression may receive two different treatment strategies: SysTx and RadTx. Our objective was to investigate the outcomes associated with these two distinct treatment pathways.

RESULTS

A total 20 patients of ALK-positive NSCLC who received first-line ALK TKI therapy and subsequently developed intracranial progression were enrolled. About 55% of patients had brain metastasis initially. Nine patients (45%) were treated with crizotinib at first. Patients treated with crizotinib demonstrated a significantly shorter intracranial PFS1 (crizotinib: 8.27 months vs. others: 27.0 months, p = 0.006). Following intracranial progression, approximately 60% of patients transitioned to the next line of systemic treatment (SysTx), while the remaining 40% opted for local cranial radiotherapy (RadTx). Intriguingly, our analysis revealed no statistically significant difference in intracranial progression-free survival (PFS2) between these two distinct treatment strategies. (SysTx: 20.87 months vs. RadTx: 28.23 months, p = 0.461).

CONCLUSION

The intracranial progression-free survival showed no difference between the two strategies suggesting that both local radiotherapy and systemic therapy may be valid options. Individualized strategy, molecular analysis, and multidisciplinary conferences may all play a pivotal role in decision-making.

Molecular heterogeneity and co-altered genes in MET-amplified ALK-positive lung cancer: Implications for MET targeted therapy

OBJECTIVES

MET amplification is a common mechanism of resistance to second- and third-generation anaplastic lymphoma kinase (ALK) inhibitors. In case series of MET-amplified ALK-rearranged (ALK + ) lung cancer, durability of responses to combinations targeting ALK and MET is variable, suggesting heterogeneity across tumors. However, little is known about the molecular composition of this subset of ALK-rearranged (ALK + ) NSCLC.

MATERIALS AND METHODS

We queried tissue and plasma databases to compile a group of > 50 specimens with ALK rearrangements and concurrent MET amplification. Fluorescence in-situ hybridization (FISH) and next-generation sequencing (NGS) were utilized to quantify the range of MET copies and describe the global molecular landscape of co-altered genes.

RESULTS

By FISH, high-level amplification (overall MET/centromere 7 probe ratio ≥ 5) was detected in 75 % of MET-amplified ALK + NSCLC tissue specimens. Intralesional heterogeneity of MET copies was observed, with high-level amplification identified even in cells from tumors with overall low-level MET amplification. Analysis of 48 MET-amplified ALK + NSCLC plasma specimens suggested that high-level amplification is rarely (17 %) detected in plasma. In both tissue and plasma, EML4-ALK variant 1 was the predominant variant (51 %) identified in MET-amplified specimens. ALK kinase domain mutations were only present in a minority of MET-amplified ALK + NSCLCs. MET-amplified ALK + NSCLC plasma specimens were enriched for TP53 mutations (81 % vs 45 %, p = 0.002), EGFR amplification (17 % vs 4 %, p < 0.001), and MYC amplification (21 % vs 3 %, p < 0.001) compared to ALK + NSCLC specimens lacking MET amplification.

CONCLUSIONS

MET-amplified, ALK + NSCLC often presents with high-level and heterogeneous amplification in tissue, seldom overlaps with ALK mutations, and frequently co-occurs with alterations associated with aggressive tumor biology.

Lorlatinib and capmatinib in a ROS1-rearranged NSCLC with MET-driven resistance: tumor response and evolution

Acquired drug resistance remains a major problem across oncogene-addicted cancers. Elucidation of mechanisms of resistance can inform rational treatment strategies for patients relapsing on targeted therapies while offering insights into tumor evolution. Here, we report acquired MET amplification as a resistance driver in a ROS1-rearranged lung adenocarcinoma after sequential treatment with ROS1 inhibitors. Subsequent combination therapy with lorlatinib plus capmatinib, a MET-selective inhibitor, induced intracranial and extracranial tumor response. At relapse, sequencing of the resistant tumor revealed a MET D1246N mutation and loss of MET amplification. We performed integrated molecular analyses of serial tumor and plasma samples, unveiling dynamic alterations in the ROS1 fusion driver and MET bypass axis at genomic and protein levels and the emergence of polyclonal resistance. This case illustrates the complexity of longitudinal tumor evolution with sequential targeted therapies, highlighting challenges embedded in the current precision oncology paradigm and the importance of developing approaches that prevent resistance.

Successful Treatment with Crizotinib to Overcome Drug Resistance Possibly Due to Mesenchymal-epithelial Transition Amplification in a Lung Cancer Patient with the Echinoderm Microtubule-associated Protein-like 4-anaplastic Lymphoma Kinase Fusion Gene

Amplification of the mesenchymal-epithelial transition (MET) gene plays an important role in anticancer drug resistance to anaplastic lymphoma kinase-tyrosine kinase inhibitors (ALK-TKIs) in echinoderm microtubule-associated protein-like 4-anaplastic lymphoma kinase (EML4-ALK)-rearranged lung cancer cells. We encountered an ALK-rearranged lung cancer patient who developed MET amplification after alectinib treatment and showed an effective response to fifth-line crizotinib. First-line alectinib treatment was effective for 2.5 years; however, liver metastases exacerbated. Liver biopsy specimens revealed MET and human epidermal growth factor receptor 2 (HER2) amplifications. Switching to the MET inhibitor crizotinib improved liver metastases. Crizotinib may be effective in ALK-positive patients with MET amplification.

The development of amivantamab for the treatment of non-small cell lung cancer

Non-small cell lung cancer (NSCLC) patients with sensitizing oncogenic driver mutations benefit from targeted therapies. Tyrosine kinase inhibitors are highly effective against classic sensitizing epidermal growth factor receptor (EGFR) mutations, such as exon 19 deletions and exon 21 L858R point mutations. Conversely, EGFR exon 20 insertions (exon20ins) are resistant to the traditional EGFR tyrosine kinase inhibitors (TKIs). In May 2021, the US Federal Drug Administration (FDA) provided accelerated approval to amivantamab (Rybrevant) in adults with locally advanced or metastatic NSCLC with EGFR exon20ins after treatment with platinum-based chemotherapy. Amivantamab was the first EGFR/MET bispecific antibody to be approved specifically for EGFR exon20ins where there was an unmet need. Furthermore, amivantamab is being evaluated in additional settings such as post osimertinib in sensitizing EGFR mutations as well as in MET altered NSCLC. Here we discuss amivantamab in regard to its mechanism of action, preclinical and clinical data, and clinical impact for patients with EGFR exon20ins NSCLC and beyond.

ALK fusions in the pan-cancer setting: another tumor-agnostic target?

Anaplastic lymphoma kinase (ALK) alterations (activating mutations, amplifications, and fusions/rearrangements) occur in ~3.3% of cancers. ALK fusions/rearrangements are discerned in >50% of inflammatory myofibroblastic tumors (IMTs) and anaplastic large cell lymphomas (ALCLs), but only in ~0.2% of other cancers outside of non-small cell lung cancer (NSCLC), a rate that may be below the viability threshold of even large-scale treatment trials. Five ALK inhibitors -alectinib, brigatinib, ceritinb, crizotinib, and lorlatinib-are FDA approved for ALK-aberrant NSCLCs, and crizotinib is also approved for ALK-aberrant IMTs and ALCL, including in children. Herein, we review the pharmacologic tractability of ALK alterations, focusing beyond NSCLC. Importantly, the hallmark of approved indications is the presence of ALK fusions/rearrangements, and response rates of ~50-85%. Moreover, there are numerous reports of ALK inhibitor activity in multiple solid and hematologic tumors (e.g., histiocytosis, leiomyosarcoma, lymphoma, myeloma, and colorectal, neuroendocrine, ovarian, pancreatic, renal, and thyroid cancer) bearing ALK fusions/rearrangements. Many reports used crizotinib or alectinib, but each of the approved ALK inhibitors have shown activity. ALK inhibitor activity is also seen in neuroblastoma, which bear ALK mutations (rather than fusions/rearrangements), but response rates are lower (~10-20%). Current data suggests that ALK inhibitors have tissue-agnostic activity in neoplasms bearing ALK fusions/rearrangements.

Targeting MET Amplification: Opportunities and Obstacles in Therapeutic Approaches

The MET gene plays a vital role in cellular proliferation, earning it recognition as a principal oncogene. Therapies that target MET amplification have demonstrated promising results both in preclinical models and in specific clinical cases. A significant obstacle to these therapies is the ability to distinguish between focal amplification and polysomy, a task for which simple MET copy number measurement proves insufficient. To effectively differentiate between the two, it is crucial to utilize comparative measures, including in situ hybridization (ISH) with the centromere or next generation sequencing (NGS) with adjacent genes. Despite the promising potential of MET amplification treatment, the judicious selection of patients is paramount to maximize therapeutic efficacy. The effectiveness of MET inhibitors can fluctuate depending on the extent of MET amplification. Future research must seek to establish the ideal threshold value for MET amplification, identify the most efficacious combination therapies, and innovate new targeted treatments for patients exhibiting MET amplification.

SHP2 Inhibition Sensitizes Diverse Oncogene-Addicted Solid Tumors to Re-treatment with Targeted Therapy

Rationally targeted therapies have transformed cancer treatment, but many patients develop resistance through bypass signaling pathway activation. PF-07284892 (ARRY-558) is an allosteric SHP2 inhibitor designed to overcome bypass-signaling-mediated resistance when combined with inhibitors of various oncogenic drivers. Activity in this setting was confirmed in diverse tumor models. Patients with ALK fusion-positive lung cancer, BRAFV600E-mutant colorectal cancer, KRASG12D-mutant ovarian cancer, and ROS1 fusion-positive pancreatic cancer who previously developed targeted therapy resistance were treated with PF-07284892 on the first dose level of a first-in-human clinical trial. After progression on PF-07284892 monotherapy, a novel study design allowed the addition of oncogene-directed targeted therapy that had previously failed. Combination therapy led to rapid tumor and circulating tumor DNA (ctDNA) responses and extended the duration of overall clinical benefit.

SIGNIFICANCE

PF-07284892-targeted therapy combinations overcame bypass-signaling-mediated resistance in a clinical setting in which neither component was active on its own. This provides proof of concept of the utility of SHP2 inhibitors in overcoming resistance to diverse targeted therapies and provides a paradigm for accelerated testing of novel drug combinations early in clinical development. See related commentary by Hernando-Calvo and Garralda, p. 1762. This article is highlighted in the In This Issue feature, p. 1749.

Efficacy and Tolerability of ALK/MET Combinations in Patients With ALK-Rearranged Lung Cancer With Acquired MET Amplification: A Retrospective Analysis

Introduction

MET amplification is a potentially actionable resistance mechanism in ALK-rearranged (ALK+) lung cancer. Studies describing treatment outcomes of this molecular subgroup are lacking.

Methods

We assembled a cohort of patients with ALK+ lung cancer and acquired MET amplification (identified by tissue or plasma) who received regimens targeting both ALK and MET. Efficacy and safety were assessed using the Response Evaluation Criteria in Solid Tumors version 1.1 and Common Terminology Criteria for Adverse Events version 4.03, respectively.

Results

A total of 12 patients were included in the series. MET amplification was detected after a median of 1.5 (range 1-5) lines of therapy. Four distinct regimens were implemented to address MET amplification: crizotinib (n = 2), lorlatinib plus crizotinib (n = 6), alectinib plus capmatinib (n = 3), and alectinib plus crizotinib (n = 1). Partial responses were observed in five (42%) of 12 patients, including patients who received crizotinib (n = one of two), lorlatinib plus crizotinib (n = three of six), and alectinib plus capmatinib (n = one of three). Primary progression was observed in four patients (33%). Grades 1 to 2 peripheral edema, occurring in seven (58%) patients, was found with both crizotinib and capmatinib. One patient required dose reduction of capmatinib plus alectinib for persistent grade 2 edema. Across the regimens, one patient discontinued therapy for toxicity, specifically neurocognitive toxicity from lorlatinib plus crizotinib. At progression on ALK+ MET therapy, potential resistance mechanisms included MET copy number changes and ALK kinase domain mutations.

Conclusions

Combined ALK and MET inhibition is associated with moderate antitumor activity in patients with ALK+ NSCLC with concurrent MET amplification. Prospective studies are indicated to confirm activity and identify individuals most likely to benefit from the treatment.

Overcoming MET-mediated resistance in oncogene-driven NSCLC

This study evaluates the efficacy of combining targeted therapies with MET or SHP2 inhibitors to overcome MET-mediated resistance in different NSCLC subtypes. A prevalence study was conducted for MET amplification and overexpression in samples from patients with NSCLC who relapsed on ALK, ROS1, or RET tyrosine kinase inhibitors. MET-mediated resistance was detected in 37.5% of tissue biopsies, which allow the detection of MET overexpression, compared to 7.4% of liquid biopsies. The development of drug resistance by MET overexpression was confirmed in EGFRex19del-, KRASG12C-, HER2ex20ins-, and TPM3-NTRK1-mutant cell lines. The combination of targeted therapy with MET or SHP2 inhibitors was found to overcome MET-mediated resistance in both in vitro and in vivo assays. This study highlights the importance of considering MET overexpression as a resistance driver to NSCLC targeted therapies to better identify patients who could potentially benefit from combination approaches with MET or SHP2 inhibitors.

The Development and Role of Capmatinib in the Treatment of MET-Dysregulated Non-Small Cell Lung Cancer-A Narrative Review

Non-small cell lung cancer (NSCLC) is a leading cause of death, but over the past decade, there has been tremendous progress in the field with new targeted therapies. The mesenchymal-epithelial transition factor (MET) proto-oncogene has been implicated in multiple solid tumors, including NSCLC, and dysregulation in NSCLC from MET can present most notably as MET exon 14 skipping mutation and amplification. From this, MET tyrosine kinase inhibitors (TKIs) have been developed to treat this dysregulation despite challenges with efficacy and reliable biomarkers. Capmatinib is a Type Ib MET TKI first discovered in 2011 and was FDA approved in August 2022 for advanced NSCLC with MET exon 14 skipping mutation. In this narrative review, we discuss preclinical and early-phase studies that led to the GEOMETRY mono-1 study, which showed beneficial efficacy in MET exon 14 skipping mutations, leading to FDA approval of capmatinib along with Foundation One CDx assay as its companion diagnostic assay. Current and future directions of capmatinib are focused on improving the efficacy, overcoming the resistance of capmatinib, and finding approaches for new indications of capmatinib such as acquired MET amplification from epidermal growth factor receptor (EGFR) TKI resistance. Clinical trials now involve combination therapy with capmatinib, including amivantamab, trametinib, and immunotherapy. Furthermore, new drug agents, particularly antibody-drug conjugates, are being developed to help treat patients with acquired resistance from capmatinib and other TKIs.

The Preclinical Pharmacology of Tepotinib-A Highly Selective MET Inhibitor with Activity in Tumors Harboring MET Alterations

The mesenchymal-epithelial transition factor (MET) proto-oncogene encodes the MET receptor tyrosine kinase. MET aberrations drive tumorigenesis in several cancer types through a variety of molecular mechanisms, including MET mutations, gene amplification, rearrangement, and overexpression. Therefore, MET is a therapeutic target and the selective type Ib MET inhibitor, tepotinib, was designed to potently inhibit MET kinase activity. In vitro, tepotinib inhibits MET in a concentration-dependent manner irrespective of the mode of MET activation, and in vivo, tepotinib exhibits marked, dose-dependent antitumor activity in MET-dependent tumor models of various cancer indications. Tepotinib penetrates the blood-brain barrier and demonstrates strong antitumor activity in subcutaneous and orthotopic brain metastasis models, in-line with clinical activity observed in patients. MET amplification is an established mechanism of resistance to EGFR tyrosine kinase inhibitors (TKI), and preclinical studies show that tepotinib in combination with EGFR TKIs can overcome this resistance. Tepotinib is currently approved for the treatment of adult patients with advanced or metastatic non-small cell lung cancer harboring MET exon 14 skipping alterations. This review focuses on the pharmacology of tepotinib in preclinical cancer models harboring MET alterations and demonstrates that strong adherence to the principles of the Pharmacological Audit Trail may result in a successful discovery and development of a precision medicine.

Targeting MET: Discovery of Small Molecule Inhibitors as Non-Small Cell Lung Cancer Therapy

MET has been considered as a promising drug target for the treatment of MET-dependent diseases, particularly non-small cell lung cancer (NSCLC). Small molecule MET inhibitors with mainly three types of binding modes (Ia/Ib, II, and III) have been developed. In this Review, we provide an overview of the structural features, activation mechanism, and dysregulation pathway of MET and summarize progress on the development and discovery strategies utilized for MET inhibitors as well as mechanisms of acquired resistance to current approved inhibitors. The insights will accelerate discovery of new generation MET inhibitors to overcome clinical acquired resistance.

Targeted Therapy for Non–Small Cell Lung Cancer

This article provides an updated review of the management of oncogene-driven non-small cell lung cancer. The use of targeted therapies for lung cancer driven by EGFR, ALK, ROS1, RET, NTRK, HER2, BRAF, MET, and KRAS are discussed, both in the first-line setting and in the setting of acquired resistance.

Fluorescence In Situ Hybridization (FISH) for the Characterization and Monitoring of Primary Cultures from Human Tumors

Genetic and drug sensitivity assays on primary cultures are not only of basic but also of translational interest and could eventually aid oncologists in the selection of treatments. However, cancer cells need to be identified and differentiated from the non-tumor cells always present in primary cultures. Also, successive passages can change the proportions of these two subpopulations. In this study, we propose fluorescence in situ hybridization (FISH) analysis on cell smears to determine the presence of tumor cells in primary cultures obtained from patients carrying translocations or copy number gains. FISH proved to be an easy, fast, economic, and reliable method of characterizing cell populations, which could be used repeatedly at different passages to monitor variations and to confirm the maintenance of translocations and copy number gains throughout the culture process.

MET alterations in advanced non-small cell lung cancer

Targeting the MET pathway in advanced NSCLC has been of particular interest due to its role as both a primary oncogenic driver and secondary oncogenic driver of acquired resistance. Activation of the MET pathway can occur through several mechanisms, which can complicate the diagnostic and treatment approach. Recently, several MET-directed therapies have been developed with promising results. In this narrative review, we summarize the biology and mechanism of MET as a clinically relevant driver mutation, distinct MET alterations including diagnostic challenges, significance in the setting of acquired resistance, and novel treatment strategies in advanced NSCLC.

ALK-positive lung cancer: a moving target

Anaplastic lymphoma kinase (ALK) is a potent oncogenic driver in lung cancer. ALK tyrosine kinase inhibitors yield significant benefit in patients with ALK fusion-positive (ALK+) lung cancers; yet the durability of response is limited by drug resistance. Elucidation of on-target resistance mechanisms has facilitated the development of next-generation ALK inhibitors, but overcoming ALK-independent resistance mechanisms remains a challenge. In this Review, we discuss the molecular underpinnings of acquired resistance to ALK-directed therapy and highlight new treatment approaches aimed at inducing long-term remission in ALK+ disease.

Optimal first-line treatment for metastatic ALK+ non-small cell lung cancer-a narrative review

Background and Objective

First-line treatment options for patients with advanced non-small cell lung cancer (aNSCLC) whose tumors harbour anaplastic lymphoma kinase (ALK) gene rearrangements have rapidly evolved from chemotherapy, to the first in class ALK-targeted tyrosine kinase inhibitor (TKI) crizotinib in 2011, and now include no fewer than five Food and Drug Administration (FDA)-approved ALK inhibitors. However, while superiority to crizotinib has been established, head-to-head clinical trials comparing newer generation ALK inhibitors are lacking, and decisions on optimal first-line treatment must be based on analysis of the relevant trials, with attention to systemic and intracranial efficacy, toxicity profile as well as consideration of patient factors and preferences. Here we aim to synthesise findings from review of these trials and to describe options for optimal first-line treatment for ALK+ NSCLC.

Methods

A literature review of relevant randomised clinical trials was undertaken using Embase database. There were no limitations to time frame or language applied.

Key Content and Findings

Crizotinib was established as the standard of care first-line treatment for patients with ALK+ aNSCLC in 2011. Since this time, alectinib, brigatinib, ensartinib and lorlatinib have all demonstrated superiority as first-line treatments compared to crizotinib, based on progression free survival, intra-cranial efficacy, and side-effect profiles.

Conclusions

Options for optimal first-line treatment for ALK+ aNSCLC include alectinib, brigatinib and lorlatinib. This review serves as a resource summarizing data from key clinical trials with ALK inhibitors to aid in decision making when tailoring treatment for patients. Future research in the field includes real world analysis of efficacy and toxicity of next-generation ALK-inhibitors, identification of mechanisms of tumor persistence and acquired resistance, development of novel ALK inhibitors, and use of ALK-TKIs in earlier stage disease.

Treatment of advanced non-small cell lung cancer with driver mutations: current applications and future directions

With the improved understanding of driver mutations in non-small cell lung cancer (NSCLC), expanding the targeted therapeutic options improved the survival and safety. However, responses to these agents are commonly temporary and incomplete. Moreover, even patients with the same oncogenic driver gene can respond diversely to the same agent. Furthermore, the therapeutic role of immune-checkpoint inhibitors (ICIs) in oncogene-driven NSCLC remains unclear. Therefore, this review aimed to classify the management of NSCLC with driver mutations based on the gene subtype, concomitant mutation, and dynamic alternation. Then, we provide an overview of the resistant mechanism of target therapy occurring in targeted alternations ("target-dependent resistance") and in the parallel and downstream pathways ("target-independent resistance"). Thirdly, we discuss the effectiveness of ICIs for NSCLC with driver mutations and the combined therapeutic approaches that might reverse the immunosuppressive tumor immune microenvironment. Finally, we listed the emerging treatment strategies for the new oncogenic alternations, and proposed the perspective of NSCLC with driver mutations. This review will guide clinicians to design tailored treatments for NSCLC with driver mutations.

Response and acquired resistance to MET inhibitors in de novo MET fusion-positive advanced non-small cell lung cancer

OBJECTIVES

De novo mesenchymal-to-epithelial transition (MET) gene fusions in non-small cell lung cancer (NSCLC) are a promising target for MET tyrosine kinase inhibitors (TKIs). We aimed to examine the response to targeted therapy with MET TKIs and resistance mechanisms in de novo MET fusion-positive NSCLC as these have not been comprehensively explored.

MATERIALS AND METHODS

We examined the MET fusions in 4,429 patients with advanced-stage NSCLC using targeted next-generation sequencing and validated the results using RT-PCR. We analyzed cellular models harboring MET fusions and established a patient-derived organoid (PDO) model.

RESULTS

We identified 13 (0.29 %, 13/4429) patients with de novo MET fusions and found EPHB4, THAP5, TNPO3, and DST as novel MET fusion partners. The most common concomitant gene with MET fusions was TP53 mutations. Among 12 patients receiving MET TKI treatment, two achieved stable disease, six achieved partial response, and four underwent progressive disease. An in vitro study showed that EPHB4-MET is a functional driver gene. MET inhibitors significantly inhibited the proliferation and phosphorylation of downstream STAT3, AKT, and ERK1/2 in EPHB4-MET overexpressing cells. Acquired MET D1228H/N or D1246N mutations were found in patients harboring MET fusions after acquiring resistance to MET TKIs. Tivantinib showed optimal suppression efficacy in a PDO model with an acquired MET D1228N mutation.

CONCLUSION

MET fusions occur in a rare subset of patients with NSCLC and represent a promising therapeutic target. MET secondary mutations D1228H/N or D1246N present the potential resistance mechanisms of MET inhibitors in patients with de novo MET fusions.

Clinically relevant fusion oncogenes: detection and practical implications

Mechanistically, chimeric genes result from DNA rearrangements and include parts of preexisting normal genes combined at the genomic junction site. Some rearranged genes encode pathological proteins with altered molecular functions. Those which can aberrantly promote carcinogenesis are called fusion oncogenes. Their formation is not a rare event in human cancers, and many of them were documented in numerous study reports and in specific databases. They may have various molecular peculiarities like increased stability of an oncogenic part, self-activation of tyrosine kinase receptor moiety, and altered transcriptional regulation activities. Currently, tens of low molecular mass inhibitors are approved in cancers as the drugs targeting receptor tyrosine kinase (RTK) oncogenic fusion proteins, that is, including ALK, ABL, EGFR, FGFR1-3, NTRK1-3, MET, RET, ROS1 moieties. Therein, the presence of the respective RTK fusion in the cancer genome is the diagnostic biomarker for drug prescription. However, identification of such fusion oncogenes is challenging as the breakpoint may arise in multiple sites within the gene, and the exact fusion partner is generally unknown. There is no gold standard method for RTK fusion detection, and many alternative experimental techniques are employed nowadays to solve this issue. Among them, RNA-seq-based methods offer an advantage of unbiased high-throughput analysis of only transcribed RTK fusion genes, and of simultaneous finding both fusion partners in a single RNA-seq read. Here we focus on current knowledge of biology and clinical aspects of RTK fusion genes, related databases, and laboratory detection methods.

Cerebrospinal fluid-derived circulating tumor DNA is more comprehensive than plasma in NSCLC patients with leptomeningeal metastases regardless of extracranial evolution

Introduction

Metastases to the central nervous system (CNS) are devastating neurological complications. Circulating cell-free tumor DNA (ctDNA) from cerebrospinal fluid (CSF) better represents genomic alterations in CNS tumors compared to plasma (PLA). However, the clinical value of cerebrospinal fluid (CSF) as a liquid biopsy medium in non-small cell lung cancer patients with leptomeningeal metastases (NSCLC-LM), regardless of extracranial evolution, remains unclear.

Patients and methods

14/48 NSCLC-BM patients and 34/48 NSCLC-LM patients were enrolled in this study. The genomic mutation profiles in CSF and matched PLA for patients with single CNS progression (cohort one, N = 22) or intracranial progression with extracranial disease progression (cohort two, N = 12) were compared. ctDNA in the CSF and simultaneously collected PLA was subjected to next-generation target sequencing (NGS) of 168 cancer-relevant genes.

Results

CSF is more comprehensive of driver genomic mutation profile than in matched PLA in patients with a single CNS progression. In addition, potential prognostic markers are much higher in CSF samples than related PLA. For example, the detection rate of EGFR-amp in CSF was more than twice of the rate in matched PLA. Moreover, CDKN2A/B, PIK3CA/G, CDK4/6, and MET were detected uniquely in CSF samples and, all of these genetic mutations were correlated with poor outcomes.Almost all genetic mutation profiles detected in PLA could be seen in matched CSF samples in cohort two. With the driver genes, such as EGFR or ALK, have a higher detection rate in CSF compared to PLA. Moreover, the potential survival maker genes CDK4/6 (6/12, 50%), CDKN2A/B (2/12, 17%), EGFR-amp (1/12, 8%), MET (1/12, 8%), and PIK3CA (1/12, 8%) were unique to the CSF samples.

Conclusion

For NSCLC -LM patients, regardless of single intracranial progression or intracranial progression simultaneously with extracranial evolution, CSF is superior to matched PLA.

Molecular pathways, resistance mechanisms and targeted interventions in non-small-cell lung cancer

Lung cancer is the leading cause of cancer-related mortality worldwide. The discovery of tyrosine kinase inhibitors effectively targeting EGFR mutations in lung cancer patients in 2004 represented the beginning of the precision medicine era for this refractory disease. This great progress benefits from the identification of driver gene mutations, and after that, conventional and new technologies such as NGS further illustrated part of the complex molecular pathways of NSCLC. More targetable driver gene mutation identification in NSCLC patients greatly promoted the development of targeted therapy and provided great help for patient outcomes including significantly improved survival time and quality of life. Herein, we review the literature and ongoing clinical trials of NSCLC targeted therapy to address the molecular pathways and targeted intervention progress in NSCLC. In addition, the mutations in EGFR gene, ALK rearrangements, and KRAS mutations in the main sections, and the less common molecular alterations in MET, HER2, BRAF, ROS1, RET, and NTRK are discussed. The main resistance mechanisms of each targeted oncogene are highlighted to demonstrate the current dilemma of targeted therapy in NSCLC. Moreover, we discuss potential therapies to overcome the challenges of drug resistance. In this review, we manage to display the current landscape of targetable therapeutic patterns in NSCLC in this era of precision medicine.

Hallmarks of Anaplastic Lymphoma Kinase Inhibitors with Its Quick Emergence of Drug Resistance

Anaplastic lymphoma kinase (ALK) is one of the most popular targets for anticancer therapies. In the past decade, the use of anaplastic lymphoma tyrosine kinase inhibitors (ALK-TKIs), including crizotinib and ceritinib, has been a reliable and standard options for patients with lung cancer, particularly for patients with nonsmall cell lung carcinoma. ALK-targeted therapies initially benefit the patients, yet, resistance eventually occurs. Therefore, resistance mechanisms of ALK-TKIs and the solutions have become a formidable challenge in the development of ALK inhibitors. In this review, based on the knowledge of reported ALK inhibitors, we illustrated the crystal structures of ALK, summarized the resistance mechanisms of ALK-targeted drugs, and proposed potential therapeutic strategies to prevent or overcome the resistance.

Non-Small Cell Lung Cancer Targeted Therapy: Drugs and Mechanisms of Drug Resistance

The advent of precision medicine has brought light to the treatment of non-small cell lung cancer (NSCLC), expanding the options for patients with advanced NSCLC by targeting therapy through genetic and epigenetic cues. Tumor driver genes in NSCLC patients have been uncovered one by one, including epidermal growth factor receptor (EGFR), mesenchymal lymphoma kinase (ALK), and receptor tyrosine kinase ROS proto-oncogene 1 (ROS1) mutants. Antibodies and inhibitors that target the critical gene-mediated signaling pathways that regulate tumor growth and development are anticipated to increase patient survival and quality of life. Targeted drugs continue to emerge, with as many as two dozen approved by the FDA, and chemotherapy and targeted therapy have significantly improved patient prognosis. However, resistance due to cancer drivers' genetic alterations has given rise to significant challenges in treating patients with metastatic NSCLC. Here, we summarized the main targeted therapeutic sites of NSCLC drugs and discussed their resistance mechanisms, aiming to provide new ideas for follow-up research and clues for the improvement of targeted drugs.