Patients with truly unmethylated MGMTp do not benefit from TMZ treatment. The OS of truly MGMTp unmethylated patients, split by treatment arm, is illustrated by Kaplan–Meier plots for the trial populations. (A) In the Nordic/NOA8 population, a significant difference was observed between TMZ treatment and RT (P = .0381). Shorter survival was observed for patients treated with TMZ. (B) The comparison of RT versus RT/TMZ→TMZ in the truly MGMTp unmethylated patients of the CE.6 trial showed no OS difference between treatments (P = .1980).