A Randomized Double Blind Controlled Proof of Concept Study of the Efficacy and Safety of Valcyte® as an add-on Therapy in Patients With Malignant Glioblastoma With Successful Surgical Resection of at Least 90 % of the Initial Tumor and CMV Infection Demonstrated Histologically and Immunohistochemically.

The purpose of this study is to investigate if treatment of CMV infection by antiviral drug Valcyte (R) affects the clinical outcome of glioblastoma multiforme in patients with local CMV infection in tumor tissue. The investigators' hypothesis states that CMV infection promotes tumor development and disease progression and inhibits immune responses against the tumor.