Angiogenic factors in relation to clinical effect in a phase II trial of weekly paclitaxel.

Background: Several anticancer agents including paclitaxel have an inhibitory effect on angiogenesis.

Aims: To compare the overall response rate and time to progression with changes in circulating angiogenic factors during palliative treatment with weekly paclitaxel.

Material And Methods: Patients with metastatic BC, ECOG 0-2, received weekly paclitaxel, concomitant with trastuzumab if HER2+ BC (n = 7). Circulating vascular endothelial growth factor (VEGF) and basic fibroblast growth factor (bFGF) were determined at base-line and before start of new course.

Results: Fifty-five of 63 included patients were evaluable. The overall response rate including stable disease ≥24 weeks (CR + PD + SD) was obtained in 25 of the evaluable patients (45%). The median time to progression (TTP) was 5.3 months and overall survival (OS) 16.7 months. Patients with triple negative breast cancer (TNBC) showed a trend towards higher base-line VEGF compared with hormone receptor positive or HER2+ tumours and had shorter TTP. Significant differences in VEGF and bFGF levels at 12 weeks were found between patients with longer versus shorter TTP (VEGF: p = 0.046, bFGF: p = 0.005) and between patients gaining versus lacking clinical benefit (VEGF: p = 0.05, bFGF: p = 0.02).

Conclusions: The clinical utility of circulating VEGF may be a useful tool for monitoring treatment efficacy.