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P1.01 - Advanced NSCLC (ID 757)
- Event: WCLC 2017
- Type: Poster Session with Presenters Present
- Track: Advanced NSCLC
- Presentations: 1
- Coordinates: 10/16/2017, 09:30 - 16:00, Exhibit Hall (Hall B + C)
P1.01-016 - Next-Generation Sequencing Shows Mechanisms of Intrinsic Resistance in ALK-Positive NSCLC Patients Treated with Crizotinib (ID 9514)
09:30 - 16:00 | Author(s): Z. Kan
Crizotinib (XALKORI®) is a small molecule ALK, ROS1, and c-MET tyrosine kinase inhibitor approved for the treatment of patients with ALK-positive or ROS1-positive metastatic NSCLC. PROFILE 1005 was a single arm phase 2 study of the safety and efficacy of crizotinib in previously treated patients with advanced NSCLC that is ALK-positive as determined by the investigational use only FISH test or on a case-by-case basis using a local FISH, IHC or RT-PCR laboratory developed test. In this study 54.1% of patients exhibited a confirmed complete or partial response to crizotinib (responders) by investigator assessment, while 9.9% had a best overall tumor response of progressive disease (progressors). The objective of this analysis was to investigate mechanisms of intrinsic resistance to crizotinib by comparing progressors with responders through a targeted cancer gene panel of next-generation sequencing (NGS).
Archival tumor tissue used to screen patients for enrollment was analyzed using the FoundationOne NGS panel (Cambridge, MA). Results of the analyses from tumor tissue positive by ALK FISH were compared for a subgroup of progressors (N=22) with a randomly selected subgroup of responders (N=25).
There was a higher proportion of patients who were ALK-negative by NGS in progressors (8 of 22; 36%) as compared to responders (3 of 25; 12%) (p=0.083), including 5 patients with oncogenic driver mutations in KRAS (G12S, Q61H, amp), EGFR (L858R) and BRAF (G469A). Among responders, 4 patients (16%) had non-EML4 ALK fusions (KIDINS220, EDC4, DTWD2, AFF2) while no such case was detected in progressors. TP53 mutations were detected in 10 progressors (45%) and 5 responders (20%) (p=0.115). Excluding NGS-negative patients, TP53 mutations were detected in 7 of 14 progressors (50%) and 3 of 22 responders (13%) (p=0.026).
In the small percentage of patients with ALK-positive NSCLC with a best response of progression upon treatment with crizotinib, a higher proportion are ALK-negative by NGS, representing either a technical false-positive or an accurate FISH result reflecting a non-activating gene rearrangement that is not detected by NGS. TP53 mutations were observed at a higher frequency in progressors than in responders in patients with ALK-positive NSCLC by both FISH and NGS. Both technical and biologic factors thus may contribute to apparent intrinsic resistance in patients with ALK-positive NSCLC treated with crizotinib.