Imatinib is active in glioblastoma multiforme expressing platelet-derived growth factor receptor

Objective: To report on 15 patients with recurrent anaplastic astrocytoma (AA) or glioblastoma multiforme (GBM) previously treated with standard therapies and, then, treated with imatinib. Methods: Fifteen consecutive patients with recurrent AA or GBM, positive immunostaining for the PDGF-alpha and progression on previous standard therapies (surgery, radiation and chemotherapy with temozolomide) were treated with imatinib (400 mg/day), administered until progression or unacceptable toxicity. Rresults: One patient achieved a confirmed partial response that lasted for 15 months. In addition, two patients had disease stabilization for eight and 19 months. Treatment was well tolerated and no patient had to be removed due to adverse events. Cconclusions: Imatinib seems to be safe and active in patients with high grade astrocytic tumors that express the PDGF-alpha receptor. Based on these results, we initiated phase II trial of high-dose imatinib (800 mg/day) in patients with recurrent AA or GBM.