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MA26 - New Therapies and Emerging Data in ALK, EGFR and ROS1 (ID 930)
- Event: WCLC 2018
- Type: Mini Oral Abstract Session
- Track: Targeted Therapy
- Presentations: 1
- Coordinates: 9/26/2018, 13:30 - 15:00, Room 201 BD
MA26.06 - Crizotinib-Treated ALK Immunopositive Metastasized NSCLC is Associated with an Unfavorable Prognosis when FISH Negative (ID 13179)
14:05 - 14:10 | Author(s): Idris Bahce
Metastasized NSCLC with an ALK fusion are sensitive to a range of tyrosine kinase inhibitors. ALK-positive NSCLC has been identified in the pivotal phase III trial with fluorescence in situ hybridization (ALK FISH+). These tumors are also expressing the fusion product (ALK immunohistochemistry (IHC)+). However, discrepant cases occur, including ALK IHC+ FISH-. The aim of this study was to collect ALK IHC+ cases and compare within this group response to crizotinib treatment of ALK FISH+ cases with ALK FISH- cases.a9ded1e5ce5d75814730bb4caaf49419 Method
A prospective multicenter investigator initiated research study was started in Europe. Stage IV ALK IHC+ NSCLC cases treated with crizotinib were collected centrally. Slides were validated centrally for ALK IHC (with 5A4 ETOP and D5F3 Ventana protocol) and ALK FISH (Vysis probes).4c3880bb027f159e801041b1021e88e8 Result
The study started April 1, 2014 and closed in November 2017. Fifteen centers participated. Registration of 3523 ALK IHC tests revealed prevalence of 2.6% ALK IHC+ cases. Local ALK FISH analysis resulted in 46 concordant (ALK IHC+/FISH+) and 18 discordant (ALK IHC+/FISH-) cases. Central validation revealed 37 concordant and 6 discordant cases, 5 of which had follow-up. Validation was hampered by limited amount of tissue in biopsy samples. The time to treatment failure did not differ for concordant nor discordant cases, and neither for local nor validated ALK testing (HR=0.78; 95% CI= 0.27-2.3; p=0.64) and (HR=2.2; 95% CI= 0.72-6.5; p=0.16), respectively). However, overall survival was significantly better for concordant cases than discordant cases after central validation (HR=4.5; 95% CI= 1.2-15.9; p=0.010), but not according to local testing (HR=1.7; 95% CI= 0.45-6.2; p=0.44).8eea62084ca7e541d918e823422bd82e Conclusion
ALK IHC+ FISH- NSCLC cases are an infrequent finding. We recommend such cases to be validated carefully because our data indicate that ALK IHC+ FISH- cases have a worse survival when treated by crizotinib compared to ALK IHC+ FISH+ cases.
This study was funded by an independent research grant by Pfizer6f8b794f3246b0c1e1780bb4d4d5dc53
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