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C. Chamizo



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    P2.06 - Poster Session 2 - Prognostic and Predictive Biomarkers (ID 165)

    • Event: WCLC 2013
    • Type: Poster Session
    • Track: Biology
    • Presentations: 1
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      P2.06-042 - Thymidylate synthase expression as predictive biomarker of pemetrexed sensitivity in advanced thoracic cancer patients. (ID 2972)

      09:30 - 09:30  |  Author(s): C. Chamizo

      • Abstract

      Background
      Although a high level of thymidylate synthase (TS) expression in malignant tumours has been suggested to be related to a reduced sensitivity to the antifolate drug pemetrexed, no direct evidence for such an association has been demonstrated in routine clinical samples from patients treated with this drug. The purpose of this study was to evaluate the impact of quantitative TS expression in tumor cells as predictor of the efficacy in patients with advanced non-small cell lung cancer, small cell lung cancer (SCLC) and mesothelioma treated with pemetrexed in our institution.

      Methods
      54 patients were included in this study: 40 stage IV NSCLC (26 adenocarcinomas, 11 large cell, and 3 squamous cell carcinoma), 3 SCLC and 11 mesothelioma. 21 patients received platins-pemetrexed as first line NSCLC, 20 pemetrexed in monotherapy as second and further lines and 3 carboplatin-pemetrexed fo extensive disease SCLC. Total RNA was isolated by RNeasy FFPE procedure (Qiagen). The expression of TS was analyzed by RT-qPCR using appropriate mRNA specific primers and probes in LightCycler 480II platform at 45 cycles. TS levels was calibrated to expression in normal tissue.

      Results
      From 54 cases, TS expression data were available in 32 cases, detecting overexpression in 23 (71.8%) and low expression in 9 (28.2%) patients. The response rate for patients with low TS expression was 0.63 compared with 0.15 in patients with overexpression (p=0.015). A significant benefit in time to progression was observed in patients with low expression (median TTP 12 vs. 2 months respectively, p= 0.002), whereas did not impact on overall survival (median OS 20 vs. 19 months respectively, p= 0.595).

      Conclusion
      TS overexpression in tumor cells correlated with a reduced response to pemetrexed-containing chemotherapy and might be used as a predictive biomarker in advanced lung and mesothelioma cancer patients.

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    P3.06 - Poster Session 3 - Prognostic and Predictive Biomarkers (ID 178)

    • Event: WCLC 2013
    • Type: Poster Session
    • Track: Biology
    • Presentations: 1
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      P3.06-044 - KRAS, EGFR mutations and EGFR gene copy status as predictive markers of response and time to progression in EGFR wild-type stage IV non-small cell lung cancer (NSCLC) patients treated with EGFR tyrosine-kinase inhibitors. (ID 2991)

      09:30 - 09:30  |  Author(s): C. Chamizo

      • Abstract

      Background
      KRAS mutations on codons 12, 13 and 61 result in the constitutive activation of protein, which may render tumor cells independent of Epidermal Growth Factor Receptor (EGFR) signalling and thereby resistant to tyrosine-kinase inhibitor (TKI) therapy in NSCLC patients. This study was aimed to evaluate the associations of KRAS and EGFR copy number alteration and mutations with response and time to progression (TTP) in EGFR TKI treated patients.

      Methods
      KRAS mutations on codons 12, 13 and 61 result in the constitutive activation of protein, which may render tumor cells independent of Epidermal Growth Factor Receptor (EGFR) signalling and thereby resistant to tyrosine-kinase inhibitor (TKI) therapy in NSCLC patients. This study was aimed to evaluate the associations of KRAS and EGFR copy number alteration and mutations with response and time to progression (TTP) in EGFR TKI treated patients.

      Results
      KRAS mutation was detected in 15 (17.8%) cases, EGFR mutation in 27 (32.1%) and EGFR amplification in 8 (9.5%). Significant differences were detected in response rates for wild-type compared with mutant KRAS ( 20 vs 0%, p=0.023), mutant compared with wild-type EGFR (59 vs 8%, p=0.007), and EGFR-amplified compared with non-amplified (71 vs 18%, p=0.005). Additionally, significant benefit from TKI therapy was observed for KRAS wild-type compared with KRAS mutated patients (median TTP 7 vs. 3 months, p=0.001), for EGFR-mutated compared with wild-type patients (14 vs. 4 months, p=0.004) and for EGFR-amplification in contrast to non-amplified cases (11 vs. 5 months, p=0.001). KRAS and EGFR mutations or EGFR amplification did not correlated with overall survival (18 vs. 19 months, p=0.406; 16 vs. 21 p=0.094; 25 vs. 17 months, p=0.103, respectively). Combined analysis of favourable status of three biomarkers strongly predicted benefit to TKI therapy (median TTP 15 vs. 3 months, p<0.001).

      Conclusion
      Combined analysis of KRAS mutation, EGFR mutation and EGFR amplification in EGFR TKI treated NSCLC might provide superior predictive information than single biomarker study in these patients