Genentech, Inc. has announced study arms of a randomized, multi-centre phase II clinical study of Avastin (bevacizumab) administered alone or in combination with irinotecan chemotherapy demonstrated encouraging six-month progression-free survival (PFS) and objective response rate in patients with relapsed glioblastoma multiforme (GBM), the most common and aggressive type of brain cancer.

As assessed by independent radiological review, 36 per cent (31/85) of GBM patients treated with Avastin alone, and 51 per cent (42/82) of patients treated with Avastin in combination with chemotherapy, lived without the disease advancing within six months. No new or unexpected safety events related to Avastin have been observed in the study. The data were presented at the 12th Annual Scientific Meeting of the Society for Neuro-Oncology.

"Historical estimates suggest that only 15 per cent of patients with this aggressive type of brain cancer live without their cancer progressing within six months," said Timothy Cloughesy, M D, director, neuro-oncology Programme of the Jonsson comprehensive cancer centre at the University of California, Los Angeles and lead investigator for the study. "The findings suggested that at six months, more patients had lived without their cancer advancing when Avastin was administered as a single-agent or in combination with chemotherapy, than what we would normally expect".

"These findings exceeded our expectations, and due to the high unmet medical need of patients with relapsed GBM we plan to discuss these data with the FDA to determine next steps," said Hal Barron, MD, Genentech's senior vice president, Development and chief medical officer.

According to the American Cancer Society (ACS), the five-year survival rate for patients with GBM is 3 per cent, and has not changed in more than 25 years. The ACS estimates there will be 20,500 new cases of brain cancer and 12,740 brain cancer deaths in 2007.

Avastin is a therapeutic antibody designed to specifically inhibit vascular endothelial growth factor (VEGF), a protein that plays an important role in angiogenesis and the maintenance of existing blood vessels throughout the lifecycle of a tumour. By inhibiting VEGF, Avastin is designed to interfere with the blood supply to a tumour, which is thought to be critical to a tumour's ability to grow and spread in the body (metastasize).