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ORAL 37 - Novel Targets (ID 146)
- Event: WCLC 2015
- Type: Oral Session
- Track: Biology, Pathology, and Molecular Testing
- Presentations: 1
- Moderators:S.S. Ramalingam, E. Thunnissen
- Coordinates: 9/09/2015, 16:45 - 18:15, Mile High Ballroom 4a-4f
ORAL37.04 - Comprehensive Genomic Profiling (CGP) of Advanced Cancers Identifies MET Exon 14 Alterations That Are Sensitive to MET Inhibitors (ID 3156)
16:45 - 18:15 | Author(s): C. Lee
Amplifications and activating mutations in the c-MET proto-oncogene are known oncogenic drivers that have proven responsive to targeted therapy. Mutations causing skipping of MET exon 14 are also oncogenic, but less well characterized. We undertook comprehensive genomic profiling (CGP) of a large series of advanced cancers to further characterize MET exon 14 alterations.
DNA was extracted from 40 microns of FFPE sections from 38,028 advanced cancer cases. CGP was performed on hybridization-captured, adaptor ligation based libraries to a mean coverage depth of >500x using three versions of the FoundationOne test. Hybridization capture baits for the MET gene were identical for all three versions of the test. Base substitution, indel, copy number alteration, and rearrangement variant calls were examined to identify those nearby to the splice junctions of MET exon 14. These genomic alterations were then manually inspected to identify those likely to affect splicing of exon 14, or delete the exon entirely.
221 cases harboring MET ex14 alterations were identified. These patients had a median age of 70.5 years (range 15-88), with 97 males and 124 females. The cases were lung carcinoma (193), carcinomas of unknown primary (15), brain glioma (6), and one each of adrenal cortical carcinoma, hepatocellular carcinoma, histiocytic sarcoma, renal cell carcinoma, rhabdomyosarcoma, skin merkel cell carcinoma, and synovial sarcoma. The majority were stage IV. Identification of this alteration has lead to treatment with MET inhibitors such as crizotinib, and to durable partial responses or better exceeding 3 months in histiocytic sarcoma (1), sarcomatoid lung carcinoma (1), and nsclc (1+). Multiple patients (5+) have initiated treatment on either crizotinib or MET inhibitors in clinical development, and additional outcome data will be reported. One patient with locally advanced unresectable disease harbored a MET exon 14 skipping alteration. On initiation with treatment with an MET inhibitor, symptomatic relief was observed in 3 days, radiographic response was observed at two weeks, and resection was performed 8 weeks after initiation of the MET inhibitor.
MET exon 14 alterations define a hereto unrecognized population of advanced cancer cases, particularly in NSCLC. Multiple case reports demonstrate that these alterations confer sensitivity to multiple small molecule MET inhibitors. This finding expands the population of advanced NSCLC patients who can derive benefit from MET-targeted therapies.