A related commentary discusses these results. Despite being a negative study, several important lessons can be learned. In a subgroup analysis, the group of patients with more than minimal residual disease responded better to rindopepimut than placebo, which is counterintuitive and raises questions about the traditional approach to restrict immunotherapy trials to patients with minimal residual disease. Also, the fact that the placebo group fared better than anticipated based on historical data, makes statistical design more challenging in clinical trials because the benchmark to beat might have to evolve. Further studies will need to be done to tease out the complex interplay between the various contributors to immune system activation and to identify the specific effector cells that mediate immune response effectors that might vary depending on the type of immunotherapy. It was a well-conducted study that both answered questions about glioblastoma treatment but also posed intriguing new ones to be explored, reinforcing that a negative trial can still provide useful information.
Rindopepimut is a immunotherapeutic vaccine targeting the tumour-specific molecule epidermal growth factor receptor variant III (EGFRvIII)