METex14 mutations represent a distinct oncogenic driver in non-small-cell lung cancer (NSCLC) and have garnered significant attention due to their actionable potential. These mutations lead to skipping of exon 14, which encodes a juxtamembrane domain important for MET degradation, resulting in sustained receptor activation and oncogenic signaling. The identification of METex14 mutations has paved the way for the development and approval of targeted therapies such as MET tyrosine kinase inhibitors (TKIs), including capmatinib, tepotinib, and savolitinib, which have demonstrated substantial efficacy in advanced NSCLC harboring these alterations.

Beyond METex14, MET gene amplification and protein overexpression occur more frequently across various tumor types and are especially prominent as mechanisms of acquired resistance in cancers initially driven by other oncogenic alterations. The amplification and overexpression of MET amplify downstream signaling pathways that promote tumor cell proliferation, survival, migration, and invasion. Clinically, MET amplification and overexpression often predict sensitivity to MET-targeted therapies, although the heterogeneity of these alterations poses challenges in patient stratification and treatment optimization.

The treatment landscape for MET-altered cancers is rapidly evolving, moving beyond classical TKIs towards a diversified arsenal of therapeutic agents. Emerging evidence supports the efficacy of novel modalities including anti-MET monoclonal antibodies, bispecific antibodies, and MET-directed antibody–drug conjugates (ADCs). These agents offer alternative mechanisms to disrupt MET signaling, binding extracellular domains or delivering cytotoxic payloads specifically to MET-expressing tumor cells. This multifaceted approach aims to circumvent resistance mechanisms and improve clinical outcomes, especially in patients with resistance to TKIs or those whose tumors exhibit MET overexpression rather than mutation.

A landmark advancement in this therapeutic expansion occurred in May 2025 with the U.S. Food and Drug Administration (FDA) approval of telisotuzumab vedotin, a MET-directed ADC indicated for patients with previously treated advanced-stage nonsquamous NSCLC exhibiting high MET expression (≥50% of tumor cells with 3+ immunohistochemical staining). This ADC combines a monoclonal antibody targeting MET with a microtubule inhibitor payload, harnessing selective delivery of chemotherapy to MET-overexpressing cells, thereby minimizing systemic toxicity and enhancing antitumor activity.

Understanding the distinct adverse event profiles associated with various MET-directed therapies is becoming increasingly important in clinical practice. For MET TKIs, common toxicities include peripheral edema, nausea, and elevated liver enzymes, reflecting the on-target effects of MET inhibition in normal tissues. Conversely, MET-directed ADCs share toxicity characteristics with other conjugates, such as hematologic suppression and neuropathy, arising from the payload component. Early recognition and management of these toxicities are critical to maintain treatment adherence and optimize therapeutic benefit.

The heterogeneity of MET alterations among solid tumors necessitates robust diagnostic strategies to accurately identify patients who may benefit from MET-targeted therapies. Techniques such as next-generation sequencing (NGS), fluorescence in situ hybridization (FISH), and immunohistochemistry (IHC) are employed to detect METex14 mutations, gene amplifications, and protein overexpression, respectively. The integration of these assays into routine diagnostics expedites patient selection, ensuring personalized approaches that align with the molecular landscape of the tumor.

Crucially, MET alterations are not restricted to NSCLC but extend to other malignancies, including gastric, colorectal, hepatocellular carcinoma, and glioblastoma, albeit at varying frequencies. This broad distribution implies that therapeutic strategies targeting MET could transcend lung cancer, offering new hope for patients with MET-driven tumors in diverse anatomical and molecular contexts. Current investigations are exploring the efficacy of MET inhibitors and ADCs across these cancer types, aiming to expand the therapeutic arsenal beyond its current indications.

Resistance mechanisms to MET-targeted therapies present another formidable hurdle in clinical management. Tumor cells may acquire secondary mutations in MET that diminish TKI binding or activate alternative signaling pathways, undermining treatment efficacy over time. Combination strategies pairing MET inhibitors with agents targeting parallel pathways or immune checkpoint inhibitors are under active investigation to overcome resistance and sustain durable responses.

From a molecular standpoint, MET functions as a receptor tyrosine kinase that binds hepatocyte growth factor (HGF), initiating signaling cascades such as RAS-RAF-MEK-ERK and PI3K-AKT-mTOR, which regulate cellular proliferation, survival, and motility. Alterations that lead to constitutive MET activation hijack these pathways, fostering oncogenesis. Targeted inhibition disrupts this pathogenic signaling, reaffirming the vital role of MET in cancer biology and its promise as a therapeutic target.

The dynamic interplay between MET-driven oncogenesis and the tumor microenvironment also merits attention. MET signaling contributes to angiogenesis and modulates immune cell infiltration, factors that influence tumor progression and response to therapy. Innovative treatment paradigms combining MET-targeted agents with anti-angiogenic drugs or immunotherapies may exploit these interactions to enhance clinical efficacy.

In summary, the therapeutic targeting of MET has transitioned from a niche focus in lung cancer to a burgeoning frontier across multiple solid tumors. Advances in molecular diagnostics, novel drug modalities, and an expanding understanding of resistance mechanisms collectively inform a more nuanced approach to MET-altered cancers. As the clinical toolbox grows, the challenge will be to tailor therapies based on the specific MET alteration and tumor context, maximizing patient benefit while minimizing toxicity.

Looking forward, ongoing clinical trials and translational research continue to illuminate the complexities of MET biology and its therapeutic vulnerabilities. Real-world evidence will be indispensable in refining patient selection criteria, optimizing combination regimens, and managing adverse events. The ultimate goal remains to harness the full potential of MET targeting, transforming outcomes for patients with MET-driven malignancies across oncology.

The approval of telisotuzumab vedotin represents both a milestone and a catalyst in the field of MET-directed therapeutics. Its success exemplifies how antibody–drug conjugates can effectively exploit overexpressed oncoproteins to deliver precise cytotoxic therapy. This model is likely to inspire further innovations, including next-generation ADCs and bispecific constructs, broadening the scope of MET-targeted interventions.

With the expanding array of MET-directed interventions, clinicians and researchers must remain vigilant to the nuances of each therapeutic class. Comprehensive assessment of pharmacodynamics, resistance patterns, and toxicity profiles will inform rational sequencing and combination strategies. Such multidimensional approaches promise to elevate the standard of care for patients harboring MET alterations beyond current paradigms.

In conclusion, MET’s evolving role as a therapeutic target underscores the convergence of molecular oncology, drug development, and clinical innovation. The insights gleaned thus far embolden ongoing efforts to integrate MET-targeting agents into personalized cancer treatment frameworks, heralding a new era in the management of NSCLC and a spectrum of other solid tumors where MET aberrations are paramount.

Subject of Research: Therapeutic targeting of MET alterations in non-small-cell lung cancer (NSCLC) and other solid tumors

Article Title: Evolving roles of MET as a therapeutic target in NSCLC and beyond

Article References:

Lee, J.B., Shim, J.S. & Cho, B.C. Evolving roles of MET as a therapeutic target in NSCLC and beyond.
Nat Rev Clin Oncol (2025). https://doi.org/10.1038/s41571-025-01051-9

Image Credits: AI Generated

This comprehensive meta-analysis encompassed six pivotal clinical studies, aggregating data from a cohort of 562 patients afflicted with NSCLC who developed acquired MET-driven resistance after prior EGFR-TKI therapy. By meticulously analyzing response rates, survival metrics, and adverse events, the investigators endeavored to delineate the therapeutic landscape of MET-TKI and EGFR-TKI combination regimens in this complex clinical niche. The findings herald a significant stride forward in pinpointing efficacious intervention strategies tailored to molecular resistance profiles.

At the forefront of the results, the pooled objective response rate (ORR) to the combination of MET-TKIs and EGFR-TKIs approached an encouraging 49.2%, coupled with a disease control rate (DCR) of 78.6%. These figures suggest that nearly half of the patients manifested measurable tumor shrinkage, while over three-quarters achieved disease stabilization or better. Importantly, the median duration of response (mDOR) spanned approximately 6.85 months, indicating a substantive period during which tumor regression was sustained. Complementing these outcomes, the median progression-free survival (mPFS) reached 5.62 months, underscoring the regimen’s capacity to delay disease advancement.

Dissecting the data further, the investigators parsed out differences contingent on the generation of EGFR-TKIs employed alongside MET-TKIs. Notably, combining MET-TKIs with third-generation EGFR-TKIs yielded numerically superior outcomes compared to first-generation EGFR-TKI combinations in patients who were T790M-negative but exhibited MET-dependent resistance. While statistical significance narrowly eluded some efficacy endpoints—such as ORR (56.8% vs. 47.8%) and DCR (81.6% vs. 75%)—the median duration of response and median progression-free survival favored the third-generation combinations, with mPFS notably extending to 7.45 months versus 4.55 months in the first-generation groups (p=0.05). These observations underscore the clinical advantage offered by newer-generation EGFR inhibitors in overcoming complex resistance mechanisms.

Beyond the generational distinction of EGFR-TKIs, the meta-analysis juxtaposed the efficacy profiles of three prominent MET inhibitors: capmatinib, savolitinib, and tepotinib. Remarkably, the objective response rates across these agents converged around 48-51%, signaling broadly comparable anti-tumor activity. Disease control rates, while showing some variability—savolitinib achieving the highest at 84.9% and tepotinib the lowest at 63.3%—did not consistently translate to statistically significant differences (p=0.02 in some cases). Median durations of response and progression-free survival similarly demonstrated no marked distinctions, suggesting interchangeability of MET-TKIs in efficacy when paired with EGFR-TKIs.

Safety profiles, however, unveiled subtle yet clinically meaningful distinctions pivoting around hepatotoxicity. Capmatinib-based combinations were associated with numerically lower incidences of elevated liver enzymes—specifically, increased AST and ALT levels—when compared to savolitinib and tepotinib counterparts. For instance, elevated AST occurred in 12.8% of capmatinib-treated patients versus nearly 19% with savolitinib and 17.4% with tepotinib. Furthermore, the rate of severe treatment-related adverse events (grade ≥3 TRAEs) trended lower in the capmatinib subgroup (30%) relative to savolitinib (46.7%) and tepotinib (41.2%), bordering on statistical significance (p=0.07). These findings advocate for a nuanced assessment of safety and tolerability alongside efficacy in clinical decision-making.

Taken together, these data coalesce into a compelling argument for integrating MET-TKI plus EGFR-TKI combination therapy into the treatment paradigm for NSCLC patients exhibiting acquired MET alterations after EGFR-TKI resistance. The synergy harnessed by targeting both molecular drivers simultaneously appears instrumental in circumventing resistance, enhancing tumor response, and prolonging progression-free intervals.

Mechanistically, resistance to EGFR-TKIs in NSCLC frequently arises via MET amplification or mutation, which reactivate downstream signaling pathways such as PI3K/AKT and MAPK, circumventing EGFR inhibition. By introducing MET-TKIs, clinicians can abrogate these bypass tracks, reinstating susceptibility to EGFR inhibition. This rationale finds tangible validation in the analyzed clinical outcomes and underscores the value of comprehensive molecular profiling in tailoring targeted therapies.

Third-generation EGFR-TKIs, exemplified by osimertinib, offer refined selectivity and efficacy, particularly against resistant T790M mutations. Their preferential pairing with MET-TKIs may optimize blockade of divergent resistance pathways. This meta-analysis hints that such combinations might amplify survival benefit compared to earlier-generation EGFR-TKIs, though further confirmatory trials are warranted.

In addition to addressing resistance, safety remains paramount given the potential toxicities intrinsic to kinase inhibitors. Hepatotoxicity, manifesting as elevated aminotransferase levels, constitutes a notable adverse effect with MET-TKIs. The observed relative hepatoprotective profile of capmatinib could influence therapeutic choices, especially in patients with pre-existing hepatic concerns or when long-term treatment is anticipated.

Despite this promising therapeutic horizon, several limitations temper the current landscape. The pooled studies exhibit heterogeneity in patient selection, MET alteration definitions, and treatment regimens, necessitating cautious interpretation. The lack of randomized head-to-head comparisons between different MET-TKIs or optimized EGFR-TKI combinations leaves gaps for future research.

Nevertheless, these insights mark a pivotal advance in NSCLC management, offering a beacon of hope to patients confronting resistance to frontline EGFR-targeted therapies. Continued exploration through large-scale prospective trials, paired with real-world evidence, will be crucial to refine these regimens and solidify their role in personalized lung cancer care.

In the era of precision oncology, the marriage of MET and EGFR inhibitors epitomizes a rational, mechanism-driven approach to overcoming drug resistance. This meta-analysis not only illuminates the therapeutic promise but also charts a course for future investigation aimed at maximizing patient outcomes amidst the molecular complexity of NSCLC.

As lung cancer remains a leading cause of cancer-related mortality worldwide, innovations that extend survival and preserve quality of life have profound clinical and societal impact. The emergence of MET-TKI plus EGFR-TKI combinations represents a tangible stride toward transforming resistance from an insurmountable barrier into a manageable challenge, rekindling hope for patients and clinicians alike.

Ongoing studies are poised to delve deeper into biomarkers predicting response, optimal sequencing strategies, and combination regimens potentially incorporating immunotherapy. This integrative approach may unlock synergistic effects, further propelling survival gains and redefining standards of care in NSCLC.

Ultimately, the convergence of translational research, molecular diagnostics, and targeted therapeutics embodied by these findings underscores the dynamic evolution of cancer treatment from empirical to exquisitely tailored intervention. The future of NSCLC therapeutics promises continued breakthroughs fueled by such rigorous scientific inquiry.

Subject of Research: Combination therapy using MET tyrosine kinase inhibitors and EGFR tyrosine kinase inhibitors in NSCLC patients with EGFR mutations and acquired MET alterations.

Article Title: MET tyrosine kinase inhibitors in combination with EGFR tyrosine kinase inhibitors in NSCLC patients with EGFR mutations and acquired MET alterations: a systematic review and meta-analysis.

Article References:
Hu, D., Hu, Y., Lei, S. et al. MET tyrosine kinase inhibitors in combination with EGFR tyrosine kinase inhibitors in NSCLC patients with EGFR mutations and acquired MET alterations: a systematic review and meta-analysis. BMC Cancer 25, 732 (2025). https://doi.org/10.1186/s12885-025-14145-5

Image Credits: Scienmag.com

DOI: https://doi.org/10.1186/s12885-025-14145-5