Definition of Response
Tumor response was defined as follows: 1) Complete response (CR), complete disappearance on MR of all enhancing tumor and mass effect. 2) Partial response (PR), ≥50% reduction in tumor size by bi-dimensional measurement, as compared with the baseline measurements. Both CR and PR require a stable or decreasing dose of corticosteroids, accompanied by a stable or improving neurologic examination, and maintained for at least 8 weeks. If cerebrospinal fluid (CSF) was positive for malignant cells at presentation, then it must be negative on repeat assessment. 3) Stable disease (SD), neurologic exam is at least stable and maintenance corticosteroid dose not increased, and MR/CT imaging meets neither the criteria for PR nor progressive disease (PD). CSF can be positive or negative for malignant cells. 4) PD, progressive neurologic abnormalities or worsening neurologic status not explained by causes unrelated to tumor progression (e.g., anticonvulsant or corticosteroid toxicity, electrolyte disturbances, sepsis, hyperglycemia, etc.), OR a greater than 25% increase in the bi-dimensional measurement, taking as a reference the smallest disease measurement recorded since the start of protocol therapy, OR the appearance of a new lesion (including new appearance of malignant cells in the CSF), OR increasing doses of corticosteroids required to maintain stable neurological status or imaging. All eligible patients who received at least one dose of the study drug were evaluable for response assessment.