After a @-day treatment break , maintenance bevacizumab ( @ mg per kilogram intravenously every @ weeks ) or placebo , plus temozolomide ( @ to @ mg per square meter per day for @ days ) , was continued for six @-week cycles , followed by bevacizumab monotherapy ( @ mg per kilogram intravenously every @ weeks ) or placebo until the disease progressed or unacceptable toxic effects developed .