Simultaneous targeting of MET overexpression in EGFR mutation-positive non-small cell lung cancer can increase the benefit of EGFR-TKI therapy?

MET-FISH Evaluation Algorithm: Proposal of a Simplified Method

MET amplifications (METamp) occur in 5% of NSCLC and represent in most case mechanisms of resistance to ALK and/or EGFR-targeted therapies. METamp detection can be performed using different techniques, although Fluorescence In-Situ Hybridization (FISH) remains the gold-standard, especially in the context of subclonality. To date current evaluation algorithms of MET amplifications are time consuming. Aim of the study was to identify a faster, equally reliable diagnostic algorithm for the detection of METamp, which is currently classified in negativity and low/intermediate/high-level amplification. N=497 NSCLC cases with available MET-FISH data had been selected. The results based on the first evaluated 20 cells had been re-calculated and compared with the definitive results based on 60 cells. For n=464 (93.4%) identical results had been obtained when counting 20 cells instead of 60 cells. Thirty-three cases (5.6%) showed a discrepancy, leading to an incorrect upgrade to a higher diagnostic category (n=25) and to an incorrect downgrade (n=8). We propose a simplified, yet equally reliable MET FISH-algorithm: after accurate screening of the whole tumor slide, twenty tumor cells have to be evaluated and results calculated: If the result is negative, or if all criteria of high-level METamp are fulfilled, the case can be signed out as such. All other cases should be considered as equivocal and additional 40 cells have to be counted. Given that, reliable results can be obtained by counting 20 cells only and an "equivocal" category for cases that need further investigation have been clearly defined.

Combination of HGF/MET-targeting agents and other therapeutic strategies in cancer

MET receptor has emerged as a druggable target across several human cancers. Agents targeting MET and its ligand hepatocyte growth factor (HGF) including small molecules such as crizotinib, tivantinib and cabozantinib or antibodies including rilotumumab and onartuzumab have proven their values in different tumors. Recently, capmatinib was approved for treatment of metastatic lung cancer with MET exon 14 skipping. In this review, we critically examine the current evidence on how HGF/MET combination therapies may take advantage of synergistic effects, overcome primary or acquired drug resistance, target tumor microenvironment, modulate drug metabolism or tackle pharmacokinetic issues. Preclinical and clinical studies on the combination of HGF/MET-targeted agents with conventional chemotherapeutics or molecularly targeted treatments (including EGFR, VEGFR, HER2, RAF/MEK, and PI3K/Akt targeting agents) and also the value of biomarkers are examined. Our deeper understanding of molecular mechanisms underlying successful pharmacological combinations is crucial to find the best personalized treatment regimens for cancer patients.