Number of subjects In total, 56 patients will be enrolled in the study. The study consists of 2 arms and at least 28 patients should be randomly assigned to one of the two arms. It is expected to recruit the study patients within a period of one year. Randomisation is based on stratification according to study sites at a 1:1 ratio. Patients younger than 18 years will not be randomised but will all receive add-on therapy with Trivax. We feel that it would be not just to expect from children to understand and accept that there is a new treatment available but only every second patient will receive it. Obviously, patients younger than 18 years will not be analysed together with adult patients in the context of the study; and paediatric patients will not count towards the recruiting number of 2 x 28. Thus, the results obtained in paediatric GBM patients will not influence the outcome of the study in patients older than 18 years.