The purpose of this study is to estimate overall survival for adult patients with newly diagnosed glioblastoma multiforme treated with talampanel during radiation therapy with concurrent and adjuvant temozolomide. This study will also determine the toxicity and toxicity rate of talampanel for this therapeutic regimen.

Inclusion Criteria:

• Patients must be 18 years of age
• Patients must have histologically confirmed supratentorial Grade IV astrocytoma (glioblastoma multiforme)
• Patients must not have prior radiation therapy, chemotherapy (including Gliadel wafer), immunotherapy or therapy with a biologic agent, or hormonal therapy. Glucocorticoid therapy is allowed.
• Patients must have recovered from the immediate post-operative period and be maintained on a stable corticosteroid regimen (on increase for 5 days) prior to the start of treatment.
• Patients must have a Karnofsky performance of at least 60% or more.

Exclusion Criteria:

• Patients with serious concurrent infection or medical illness.
• Patients receiving concurrent chemotherapeutics or investigational agents.