Serum VEGF in patients (PTS) receiving bevacizimab (BEV) for early-stage breast cancer (ESBC): ICORG 08-10.

Abstract

e13520 Background: Approximately 30% of pts with ESBC develop metastasis despite apparently curative loco-regional therapy. Angiogenesis, partly mediated by vascular endothelial growth factor (VEGF), may promote metastases. BEV, an anti-VEGF monoclonal antibody which has some efficacy in metastatic BC is being studied as an adjuvant in ESBC, but there are no validated biomarkers, and the effect on VEGF levels in pts with ESBC is unknown. We studied VEGF serum concentration in ESBC receiving BEV. Methods: 106 pts with HER-2 negative ESBC were included in this study. Patients received 4 cycles of docetaxel (75 mg/m2) + cyclophosphamide (600 mg/m2) with BEV (15 mg/kg) once every three weeks for one year. Serum samples were collected prior to commencement of treatment, at 6 months and 12 months. The VEGF levels in serum samples were determined, at each time point, using a VEGF enzyme-linked immunosorbent assay (ELISA). Results: VEGF concentration was determined in serum samples from 65 patients. Three pts (5%) had no detectable VEGF at 0, 6 and 12 months. The median level of serum VEGF in the remaining 62 patients was 325.4 ± 244 pg/ml. These 62 patients showed a significant decrease in VEGF concentration after 6 and 12 months of treatment (median 9 ± 42.1 pg/ml, p<0.001 and 9 ± 43.9 pg/ml, p<0.001 respectively). However, no significant change in VEGF levels were observed at 12 months compared to 6 months (median 0 ± 60.3 pg/ml, p=0.704). Conclusions: Adjuvant therapy with chemotherapy and BEV is associated with a significant reduction in VEGF levels at 6 months.