Implications of bevacizumab (Avastin) discontinuation in adults with recurrent glioblastoma. This article looked at GBM patients who took Avastin for longer than 6 months and then discontinued it. 1/4 of the patients stopped for reasons other than tumor progression, and 3/4 stopped because of tumor progression. Then they analysed what happened, looking for a "theoretical" rebound effect. They didn't find it. Those who stopped because of other reasons did a lot better than those who stopped because of progression.