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  MA19 - Genomic Markers of IO Response (ID 922)

  • Event: WCLC 2018
  • Type: Mini Oral Abstract Session
  • Track: Immunooncology
  • Presentations: 1
  • Moderators:
  • Coordinates: 9/25/2018, 15:15 - 16:45, Room 201 BD

  • 26117

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    MA19.06 - Blood Based Biomarkers: RNA, KRAS and PD-L1 Strongly Matching with Tissue and Showing Correlation with Clinical Responses In NSCLC Patient’s (ID 12358)

    15:45 - 15:50  |  Author(s): Yolanda Jaimes
    • Abstract
    • Presentation
    • Slides

    Background
    

    Circulating cell-free tumor RNA (cfRNA) can be now safety isolated as cfDNA and used to measure changes in the tumor burden in the blood and changes in gene expression in non-small cell lung cancer (NSCLC) patients (pts). We are correlating these changes in cfRNA and PD-L1 with clinical response to therapy (chemotherapy, immunotherapy (IMMUNO) or targeted therapy) in stage IV NSCLC pts. Our group has been the first one to use cfRNA to detect PD-L1.

    a9ded1e5ce5d75814730bb4caaf49419 Method
    

    Blood was drawn from 31 pts under various treatments (tx) every 6-8 weeks, at the same time that CT scans were done. CfRNA was extracted from the resulting plasma and reverse transcribed with random hexamers to cDNA. Levels of cfRNA were quantitated by RT-qPCR and correlated with pts clinical response (CR/PR/SD/PD), as determined by CT scans.

    4c3880bb027f159e801041b1021e88e8 Result
    

    A total of 31 lung cancer pts were enrolled in a 2-year clinical study. 25 of 31 pts completed already the first two cycles of tx and had CT scans done. Of these, 6/8 pts with progressive disease (PD) showed increased (INC) levels of cfRNA, 9/13 pts with stable disease (SD) showed either no change (NC) or decreased (DEC) cfRNA, and 4/4 pts with partial response (PR) had NC or DEC cfRNA, corresponding to 76% concordance between cfRNA and clinical responses. PD-L1 expression measured in plasma cfRNA matched the tissue expression in 7/10 pts. In the one pt where PD-L1 was (-) in blood and (+) in tissue there was PD on IMMUNO. Among 8 pts treated with IMMUNO: 3/3 pts with PD showed INC PD-L1 cfRNA expression, 3/3 pts with SD had NC in negative PD-L1 status, and 2 pts with PR showed DEC PD-L1 cfRNA, corresponding to 100% correlation between PD-L1 expression levels and pt response. Of the 31 pts, 32% (10/31) harbored KRAS mutations in cfDNA. Of those with KRAS+ status by tissue-based testing, 83% matched with cfDNA results. Among KRAS+ pts, 80% (8/10) showed PD-L1 cfRNA expression in same blood draws with KRAS+ cfDNA, suggesting correlation between these cfDNA and cfRNA analyses.

    8eea62084ca7e541d918e823422bd82e Conclusion
    

    Significant association was observed between clinical response and changes in plasma cfRNA levels in NSCLC pts (76%). There was concordance between tissue- and blood-based testing in both DNA (KRAS mutations, 83%) and RNA (PD-L1 expression, 70%). While on IMMUNO levels of PD-L1 expression could be used to monitor response to immunotherapy.

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