Glioblastoma: Overcoming fundamental biological and delivery barriers to therapy.

Glioblastoma remains the most aggressive primary malignant brain tumor in adults, with survival largely unchanged despite advances in molecular diagnostics and supportive care. Therapeutic failure reflects fundamental biological and anatomical barriers, including intratumoral heterogeneity, an immunosuppressive tumor microenvironment, and restricted drug delivery across the blood-brain barrier. In this Review, we summarize the current standard of care and critically examine emerging strategies aimed at overcoming these constraints, including locoregional delivery technologies, immunotherapy, biomarker-defined precision approaches, and adaptive clinical trial designs. We highlight key translational and clinical studies shaping the field and discuss principles for developing more effective, integrated therapeutic paradigms.