Genentech Inc announced that a Phase III study of Avastin (bevacizumab, rhuMAb-VEGF) in relapsed metastatic breast cancer patients did not meet its primary efficacy endpoint of progression-free survival. Avastin is an investigational therapeutic antibody directed at vascular endothelial growth factor (VEGF).

This study randomized 462 women with metastatic breast cancer who had previously received treatment with both anthracycline and taxane-based chemotherapy regimens to receive Avastin with Xeloda (capecitabine) or Xeloda alone. One of the secondary endpoints, overall response rate, did achieve statistical significance, but this did not translate into benefit in progression-free survival or twelve-month survival.

The adverse event profile in this study was similar to the observed events in Phase II studies and included venous thrombosis, hypertension and asymptomatic proteinuria. There was no increase in serious bleeding in the Avastin arm of the study.

The randomized Phase II study in colorectal cancer, presented at the American Society of Clinical Oncology (ASCO) in 2000, demonstrated an increase in overall survival, time to disease progression and overall response rate in patients treated with Avastin in combination with chemotherapy as compared to those treated with chemotherapy alone.