Targeting Macrophages in Glioblastoma: Current Therapies and Future Directions

Glioblastoma (GBM) is an aggressive brain tumor characterized by an immunosuppressive tumor microenvironment (TME), which contributes to treatment resistance and disease progression. Background: Tumor-associated macrophages (TAMs), comprising both resident microglia and bone marrow-derived macrophages, play a central role in supporting tumor growth, angiogenesis, and immune evasion. Most TAMs adopt an M2-like immunosuppressive phenotype, making them a promising target for immunomodulatory strategies in GBM. Method: According to PRISMA guidelines, we conducted a systematic literature review and recruited eligible studies focused on therapeutic approaches targeting TAMs in GBM, emphasizing mechanisms of action, efficacy, and challenges. Data extraction focused on therapeutic classes, outcomes, and TAM-related biomarkers. Results: We identified 30 studies meeting the inclusion criteria. These therapies are categorized into three main strategies: inhibition of TAM recruitment, enhancement of TAM-mediated phagocytosis, and reprogramming of TAMs. Combination strategies, including TAM-targeting with checkpoint inhibitors, nanoparticles, and oncolytic viruses, show synergistic effects in preclinical models. Conclusions: Targeting TAMs represents a multifaceted strategy for GBM treatment. Current evidence underscores the need for combination approaches integrating TAM modulation with existing standard-of-care therapies. Clinical translation remains limited due to challenges such as TAM heterogeneity, plasticity, immunosuppressive therapies, and restricted drug delivery across the blood-brain barrier. Future directions should highlight personalized treatments based on detailed TME profiling. Combining TAM-targeted therapies with agents modulating metabolic or immune pathways, and leveraging advanced delivery systems and spatial transcriptomics may improve efficacy.