Treatment of Unresectable Adult Pilocytic Astrocytoma with Bevacizumab with or without Temozolomide (P04.183)

Abstract

Objective: We hypothesized that bevacizumab (bev) with or without temozolomide (TMZ) might be effective in treating unresectable pilocytic astrocytoma (PA) in adults. Background PA is a WHO Grade I tumor that is often not completely resectable. TMZ, an alkylating agent, and bev, a blocker of vascular endothelial growth factor (VEGF), are both approved for treatment of glioblastoma. Pathological studies have shown VEGF expression in PA. Design/Methods: We reviewed cases of unresectable PA treated with bev with or without TMZ. We identified 9 patients, 5 male and 4 female, with a median age of 40 years. Six tumors were in the hypothalamus, and 1 each in the thalamus, pineal region, and cerebral peduncle. Two patients were treated in the up-front setting, and 7 were treated for progression after radiation therapy. Three patients had received prior chemotherapy, 1 each PCV, carboplatin, or TMZ. Treatment consisted of bev 5 mg/kg every 14 days, with or without TMZ 150-200 mg/sq m every 5 of 28 days. MR scans were graded according to Macdonald criteria. Results: Seven patients were treated with TMZ plus bev and 2 with bev monotherapy. Median duration of therapy was 351 days for bev and 308 days for TMZ. Seven patients (78%) achieved a partial response, 1 a minor response, and 1 no response. Cyst volumes were decreased in 3 of 4 tumors (75%) with multicystic change. Both patients treated with bev monotherapy achieved a partial response, as did both patients treated in the up-front setting. Visual field or extraocular movement deficits improved significantly in 4 patients. One patient experienced symptomatic intratumoral hemorrhage. One patient died after craniotomy for hemorrhagic tumor progression. Median time to progression on bev was 593 days. Conclusions: Bev when administered with or without TMZ is effective in unresectable adult PA and deserves a Phase II study. Disclosure: Dr. Green has nothing to disclose. Dr. Woyshner has nothing to disclose. Dr. Quan has nothing to disclose. Dr. Cloughesy has received personal compensation for activities with Genentech, Inc., and Roche Diagnostics Corporation.