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MINI 26 - Circulating Tumor Markers (ID 148)
- Event: WCLC 2015
- Type: Mini Oral
- Track: Biology, Pathology, and Molecular Testing
- Presentations: 1
MINI26.08 - A Correlative Plasma Biomarker Analysis of the Combination of Bevacizumab and Chemotherapy for Advanced Non-Small-Cell Lung Cancer (ID 1423)
16:45 - 18:15 | Author(s): X. Wan
The addition of bevacizumab, a monoclonal antibody against vascular endothelial growth factor, to a standard, first-line platin-based, two-agent chemotherapy regimen conferred a significant improvement in overall survival, progression-free survival, and response rate in patients with advanced non-squamous NSCLC (ns-NSCLC). The feasibility of the combination of bevacizumab and chemotherapy as the second-line or more therapy for ns-NSCLC is currently explored as well. However, no effective biomarker is validated to predict the response or clinical benefit of bevacizumab. This study aims to investigate the correlation between biomarkers and overall response to bevacizumab plus chemotherapy for patients with advanced ns-NSCLC.
Patients with locally advanced or metastatic ns-NSCLC who were assigned to 7.5mg/kg 3-weekly doses of bevacizumab plus chemotherapy were eligible. Aaccording to investigators’ decision, chemotherapy regimens were pemetrexed (500mg/m) with or without platinum (75mg/m). Peripheral blood samples were collected at baseline and after 2[nd] cycle of therapy for the analysis of granulocyte colony-stimulating factor（G-CSF）, vascular endothelial growth factor A（VEGF-A） and VEGF receptor-2 (VEGFR-2). Plasma samples concomitantly with the radiological evaluation of disease progression were collected as possible. Correlation between biomarkers and overall response rate (ORR) were assessed by using a logistic regression model.
Baseline blood samples were available from 45 patients (100%, 19 patients were therapy naive, 26 patients failed of prior therapies), while samples after 2[nd] cycle were obtained from 37 patients (82.22%). For the primary analysis, there was no significant association between baseline plasma biomarkers and best overall response to the treatment. But, patients with low baseline plasma G-CSF level showed a trend toward improving ORR versus patients with high G-CSF level (odds ratio [OR], 3.846; 95%CI, 0.868 to 17.044，p＝0.076). Patients with high baseline plasma VEGF-A level showed a trend toward higher ORR versus patients with low VEGF-A levels (OR, 3.477; 95%CI, 0.857 to 14.113，p＝0.081). No significant correlations were observed between plasma biomarkers and progression-free survival (PFS). In comparison to baseline, plasma VEGF-A level increased significantly at 2[nd] cycle or radiological disease progression (p＜0.001). However, the magnitude of the difference did not correlate with ORR or PFS.
Baseline or dynamic changes in plasma G-CSF, VEGF-A and VEGFR-2 did not correlate significantly with response of bevacizumab plus chemotherapy treatment for ns-NSCLC patients, while low baseline plasma G-CSF and high VEGF-A are possible candidate biomarkers for predicting response of bevacizumab plus chemotherapy for ns-NSCLC.