Abstract 5545: Collagen-binding anti-GITR antibody reshapes immunosuppressive microenvironment and prolongs survival in recurrent glioblastoma

Key Points

• To evaluate the efficacy of a collagen-binding anti-GITR antibody in altering the tumor microenvironment and improving survival in recurrent glioblastoma.
• Developed a novel antibody, CBD-αGITR, for targeted delivery to tumor sites.
• Used mouse models and patient-derived tumor cultures to assess effectiveness.
• Performed biodistribution assays to measure antibody accumulation in tumors.
• Conducted single-cell RNA sequencing to analyze immune cell dynamics post-treatment.
• CBD-αGITR showed 20% complete remission in rGBM mouse models.
• Combined treatment with PD-1 inhibitor increased complete remission rates to 67%.
• Significant reduction of GITR+ Tregs and exhausted CD8+ T cells was observed.
• Extended survival noted in humanized models and significant Treg reduction in patient-derived cultures.