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Chang-Jiun Wu



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    MA03 - Clinomics and Genomics (ID 119)

    • Event: WCLC 2019
    • Type: Mini Oral Session
    • Track: Advanced NSCLC
    • Presentations: 1
    • Now Available
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      MA03.05 - BRAF Mutations Are Associated with Increased Benefit from PD1/PDL1 Blockade Compared with Other Oncogenic Drivers in Non-Small Cell Lung Cancer (Now Available) (ID 1472)

      10:30 - 12:00  |  Author(s): Chang-Jiun Wu

      • Abstract
      • Presentation
      • Slides

      Background

      PD-1/PD-L1 immune checkpoint blockade (ICB) has revolutionized the treatment of non-small cell lung cancer (NSCLC), but only a minority of patients achieve durable clinical benefit. Although classic EGFR/ALK alterations are correlated with ICB resistance, it is unknown if patients with other molecular subtypes of NSCLC also derive poorer outcomes from ICB. We investigated if there are oncogene-driven NSCLC associated with higher response rates (RR) and progression-free survival (PFS) to ICB.

      Method

      Two independent retrospective cohorts of oncogene-driven NSCLC treated with ICB monotherapy were analyzed for clinical outcome: MD Anderson (MDACC) and Flatiron Health-Foundation Medicine Clinico-Genomic Database (FH-CGDB). PD-L1 expression (Dako 22C3 - FoundationCore) and tumor mutational burden (TMB - FoundationCore; TCGA and MSK-IMPACT – cbioportal.org) were compared across distinct molecular subtypes of NSCLC to determine differences in clinical outcome.

      Result

      Among five oncogene defined groups from the MDACC cohort, BRAF-mutant NSCLC had the highest response rate (RR) (RECIST 1.1) (P<0.01) and PFS (P<0.01) when treated with ICB (Table). These differences remained significant after adjusting for PD-L1 expression. Classic EGFR and HER-2 mutant NSCLC had the lowest RR and PFS (Table). Similar results were observed in the independent FH-CGDB cohort where BRAF-mutant NSCLC had longer real-world (rw) PFS and OS to ICB monotherapy (Table). PD-L1 expression (tumor score ≥1% and ≥50%) and TMB were higher in BRAF-mutant NSCLC compared to EGFR and HER-2 (P<0.01). BRAF V600E NSCLC had lower TMB compared to non-V600E (5.9 vs 13.7 mut/Mb, P<0.01), but both had high PD-L1 expression (≥1%: 72% vs 61%; ≥50%: 42% vs 32%).

      KRAS

      BRAF

      Classic EGFR

      EGFR exon 20

      HER2

      MDACC cohort

      Patients – N

      87

      10 (V600E 3 / non-V600E 7)

      28

      25

      15

      RR – %

      24.3

      62.5

      4.5b

      10b

      8.3

      Median PFS – mo (95% CI)

      2.76

      (2.23-3.30)

      7.37 (not estimable)a

      1.78 (1.18-2.37)

      2.73 (1.71-3.75)

      1.88 (1.63-2.12)

      FH-CGDB

      Patients – N

      503

      68 (V600E 32 / non-V600E 36)

      52

      42

      25

      Median rwPFS -

      mo (95% CI)

      3.55

      (3.15-4.24)

      6.0

      (2.89-11.6)

      2.17b

      (1.77-2.63)

      2.66b

      (2.23-5.13)

      1.87b (1.31-4.34)

      Median rwOS – mo (95% CI)

      10.28

      (8.51-12.02)

      16.07

      (8.64-NA)

      5.29b

      (3.25-17.68)

      9.89b

      (3.68-20.86)

      10.81

      (4.17-NA)

      FoundationCore cohort – N

      NA

      188 (V600E 74 / non-V600E 114)

      386

      96

      57

      TMB – mean (mut/Mb)

      NA

      10.6a

      3.7

      3.8

      5.8

      PD-L1 TPS ≥ 50% (%)

      NA

      36a

      19

      23

      16

      a: P<0.01 vs all groups; b: P<0.05 for pairwise comparison vs BRAF.

      Conclusion

      NSCLCs with BRAF mutations are associated with increased benefit from ICB when compared to tumors harboring other targetable oncogenic drivers. Oncogene driver mutations are associated with distinct patterns of TMB and PD-L1 expression. These findings highlight the importance of developing mutation-specific clinical trials in NSCLC.

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