<qa>  What was the dose of imatinib 600 mg twice daily?This ClinicalTrials.gov record includes the results from two studies Novartis protocol IDs CSTI571H2201 and CSTI571H2202 which were conducted separately but reported together in a single clinical study report. Both studies were phase II, open-label, multicenter, single-arm studies that evaluated the efficacy of imatinib mesylate plus hydroxyurea in subjects with progressive glioblastoma multiforme. The studies were identical in design with two exceptions: Patients in study CSTI571H2201 received a dose of imatinib 600 mg once daily and were not allowed concomitant use of enzyme-inducing anticonvulsant drugs EIACDs; patients in study CSTI571H2202 received a dose of imatinib 500 mg twice daily and were allowed concomitant use of EIACDs. 