a prospective, randomly controlled pivotal study will be conducted on 700 patients (randomized at a 2:1 ratio in favor of the novoTTF-100a group) with tissue diagnosis of GBM who have completed radiation therapy together with adjuvant Temozolomide. The control group will receive standard Temozolomide maintenance therapy. The primary endpoint will be progression free survival (PFS). The sample size was chosen based on the log-rank test comparing time to event (i.e., progression or death prior to progression) assuming patients treated with the novoTTF-100a together with maintenance Temozolomide will have a median PFS significantly greater than controls (9 months compared to 7 months, respectively; with an overall 5% 2-sided type i error and 80% power). This sample size also has adequate power (80%) to detect a minimum of 4.5 month increase in median overall survival in novoTTF-100a treated patients compared with control patients (expected control group median oS [?] 14.6 months, Stupp et al, neJM 2005).
a. Pathological evidence of GBM using WHO classification criteria.
b. > 18 years of age.
c. Received maximal debulking surgery and radiotherapy concomitant with Temozolomide (45-70Gy):
1. Patients may enroll in the study if received Gliadel wafers before entering the trial
2. Any additional treatments received prior to enrollment will be considered an exclusion.
3. Minimal dose for concomitant radiotherapy is 45 Gy
d. Karnofsky scale >= 70
e. Life expectancy at least 3 months
f. Participants of childbearing age must use effective contraception.
g. All patients must sign written informed consent.
h. Treatment start date at least 4 weeks out from surgery.
i. Treatment start date at least 4 weeks out but not more than 7 weeks from the later of last dose of concomitant Temozolomide or radiotherapy