This study was designed to include patients with newly diagnosed unresectable (Arm A) and resectable (Arm B) malignant glioma. Three dose levels of AdV-tk were evaluated with a fixed dose level of valacyclovir prodrug. AdV-tk was delivered to tumor cells by stereotactic injection into the tumor at the time of biopsy (Arm A) or injection into the tumor bed following resection (Arm B). Oral valacyclovir began 1-3 days after the AdV-tk injection and continued for 14 days. Standard radiation therapy began 3-7 days following the AdV-tk injection to maximize synergy with radiation. Standard temozolomide could be administered after completion of valacyclovir.