Glioblastoma (GBM), the most common malignant primary brain tumor in adults, is resistant to Standard of Care (SOC) therapy and almost all available therapies. Clinical trials have not been successful in improving patients’ survival, which underscores an urgent need for developing new effective therapies for this treatment-refractory disease. Considering the significant inter- and intratumoral heterogeneity existing in GBM, assessment of therapies in a personalized manner would allow for assigning patients to effective targeted therapies suitable for each patient’s unique tumor signature. Patient-tailored ex vivo drug response platform for GBM allows for therapy planning in a personalized manner and enables the discovery of biomarkers of response. Advanced 3D methodologies have shown high efficacy in assessing the effect of therapeutics on intact tumor tissues immediately following tumor resection, allowing for studying the effect of therapies on tumor as a whole followed by detailed analysis of interactions between tumor cells and their microenvironment pre- and post-treatment. Here we describe the use of 3D perfusion bioreactors for translational assessment of therapeutics on regionally annotated patient-derived GBM explants. This model system provides the possibility of generating a 3D dynamic culture with continuous exposure and delivery of drug candidates to an intact tumor tissue material providing crucial insights on treatment-induced mechanisms and facilitating the identification of biomarkers of response, paving the way toward designing and generating more effective therapeutic interventions for GBM patients.