OA 12.06 Plasma Genomic Profiling and Outcomes of Patients with MET Exon 14-Altered NSCLCs Treated with Crizotinib on PROFILE 1001

MET exon 14 alterations occur in ∼4% of non-squamous non-small cell lung cancers (NSCLCs). Treatment with the MET inhibitor, crizotinib, achieves confirmed and durable responses in patients with MET exon 14-altered NSCLCs, underscoring the need to test for these drivers (as of August 1, 2016, objective response rate was 39% and median duration of response was 9.1 months). Comprehensive molecular tumor profiling is required to detect MET exon 14 alterations that are highly heterogeneous. The utility of plasma profiling to detect these drivers has not previously been explored in a prospective trial. Patients with advanced NSCLCs harboring MET exon 14 alterations by local tumor profiling performed in a CLIA-certified or equivalent environment were treated with crizotinib at 250 mg twice daily on an expansion cohort of the ongoing phase I PROFILE 1001 study (NCT00585195). Objective response was assessed by RECIST v1.0. Prospective plasma profiling of circulating tumor DNA (ctDNA) for MET exon 14 alterations was performed using the PlasmaSELECT64 targeted gene panel (sequencing and analysis output by Personal Genome Diagnostics, Boston MA). Plasma samples were obtained for MET exon 14 alteration analysis after study amendment approval in 20 of 52 crizotinib-treated patients, of which 18 samples were deemed sufficient for analysis. MET exon 14 alterations were detected in ctDNA in 11 of 18 patients (61% agreement of plasma ctDNA testing with tumor testing) mapping to the same exon 14 splice site region in 10 of the 11 cases. Of the 11 patients with ctDNA-positive tumors, all were evaluable for response. Of these evaluable patients, a confirmed partial response and stable disease were observed in 2 and 4 patients, respectively. MET exon 14 alterations can be detected in plasma ctDNA in a subset of patients with advanced NSCLCs that harbor MET exon 14 alterations by tumor testing. Responses to crizotinib were observed in patients with ctDNA-positive testing for a MET exon 14 alteration. Plasma profiling should be considered as an adjunct to tumor profiling in screening patients for MET exon 14 alterations, pending further confirmation.