Clin Cancer Res.  2020  Nov  10.  pii:  clincanres.2861.2020. [Epub  ahead  of  print]
Robin Guo, 
Michael Offin, 
A Rose Brannon, 
Jason C Chang, 
Andrew Chow, 
Lukas Delasos, 
Jeffrey Girshman, 
Olivia Wilkins, 
Caroline G McCarthy, 
Alex Makhnin, 
Christina J Falcon, 
Kerry Scott, 
Yuan Tian, 
Fabiola Cecchi, 
Todd Hembrough, 
Deepu Alex, 
Ronglai Shen, 
Ryma Benayed, 
Bob T Li, 
Charles M Rudin, 
Mark G Kris, 
Maria E Arcila, 
Natasha Rekhtman, 
Paul K Paik, 
Ahmet Zehir, 
Alexander Drilon.
 
  
PURPOSE: MET tyrosine kinase inhibitors (TKIs) can achieve modest clinical outcomes in MET exon 14-altered lung cancers, likely secondary to primary resistance. Mechanisms of primary resistance remain poorly characterized and comprehensive proteomic analyses have not previously been performed.
EXPERIMENTAL DESIGN: We performed hybrid capture-based DNA sequencing, targeted RNA sequencing, cell-free DNA sequencing, mass spectrometry (SRM-MS), and immunohistochemistry (IHC) on patient samples of MET exon 14-altered lung cancers treated with a MET TKI. Associations between overall response rate (ORR), progression free survival (PFS), and putative genomic alterations and MET protein expression were evaluated.
RESULTS: Seventy-five of 168 MET exon 14-altered lung cancers received a MET TKI. Previously undescribed (zygosity, clonality, whole genome duplication) and known (copy number focality, tumor mutational burden, mutation region/type) genomic factors were not associated with ORR/PFS (P > 0.05). In contrast, MET expression was associated with MET TKI benefit. Only cases with detectable MET expression by SRM-MS (N = 15) or IHC (N = 22) responded to MET TKI therapy, and cancers with H-score > 200 had a higher PFS than cancers below this cutoff (10.4 vs 5.5 months, respectively; hazard ratio 3.87, P = 0.02).
CONCLUSIONS: In MET exon 14-altered cancers treated with a MET TKI, a comprehensive analysis of previously unknown and known genomic factors did not identify a genomic mechanism of primary resistance. Instead, MET expression correlated with benefit, suggesting the potential role of interrogating the proteome in addition to the genome in confirmatory prospective trials.