Analysis of circulating angiogenic biomarkers from patients in two phase III trials in lung cancer of chemotherapy alone or chemotherapy and thalidomide

BACKGROUND: Thalidomide has potent anti-inflammatory and anti-angiogenic properties. It was evaluated in combination with chemotherapy in two randomised placebo-controlled trials in patients with small cell lung cancer (SCLC, n=724) and advanced non-small cell lung cancer (NSCLC, n=722). Neither study demonstrated an improvement in overall survival with the addition of thalidomide to chemotherapy. This study investigated circulating angiogenic biomarkers in a subset of these patients. METHODS: Serial plasma samples were collected in a cohort of patients enrolled in these two trials (n=95). Vascular endothelial growth factor (VEGF), soluble truncated form of VEGF receptor-2 (sVEGFR-2), interleukin-8 (IL-8), tumour necrosis factor-α (TNF-α), basic fibroblast growth factor (bFGF) and soluble intercellular adhesion molecule-1 (sICAM-1) levels were measured by enzyme-linked immunosorbent assays. Results were correlated with patient clinical data including stage, response rate and progression-free survival (PFS). RESULTS: Baseline biomarker levels were not significantly different between SCLC and NSCLC. For pooled treatment groups, limited stage SCLC was associated with lower baseline VEGF (P=0.046), sICAM-1 (P=0.008) and IL-8 (P=0.070) than extensive stage disease. Low baseline IL-8 was associated with a significantly improved PFS in both SCLC and NSCLC (P=0.028), and a greater reduction in IL-8 was associated with a significantly improved tumour response (P=0.035). Baseline angiogenic factor levels, however, did not predict response to thalidomide. CONCLUSION: Circulating angiogenic biomarkers did not identify patients who benefited from thalidomide treatment.