Cancer patients with brain metastases have until recently been excluded from clinical trials of the antiangiogenic drug Avastin® (bevacizumab) due to concerns about a possible risk of bleeding in the brain. Results from a major new analysis involving thousands of cancer patients, however, indicate that Avastin does not increase the risk for intracranial bleeding in patients with brain metastases.

Researchers examined safety data from 8,443 patients in 13 randomized clinical trials, two open-label safety trials, and two more recent prospective trials. In the 13 randomized studies, previously undiagnosed brain metastases were identified in 187 patients (91 in Avastin-treated patients, and 96 in patients not treated with Avastin). Among them, 3 Avastin-treated patients (3.3%) developed serious bleeding in the brain, whereas 1 non Avastin-treated patient (1.0%) developed a fatal cerebral hemorrhage.

In the open-label safety studies, 321 of 4,382 patients had initially undiagnosed brain metastases, of which 2 mild and 1 moderate cerebral hemorrhage (0.9%) occurred. The two prospective studies involved patients with known brain metastases who received Avastin therapy. Among 131 patients with brain metastases in these studies, only one Avastin-treated patient (0.8%) developed mild bleeding in the brain.

These results indicate that cancer patients with brain metastases have a low risk of developing cerebral hemorrhage, regardless of whether they receive Avastin. Avastin was recently approved to treat glioblastoma, a deadly form or brain cancer. Glioblastoma patients are known to be at increased risk for intracranial hemorrhage due to the nature of the disease. However, there has not been an increased incidence of cerebral hemorrhage in glioblastoma patients treated with Avastin.