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.