Phase 1/2 trial shows RT + bevacizumab + olaptesed pegol extends PFS and OS in unmethylated GBM

Rapid vascular recovery is a key feature preceding glioblastoma (GBM) recurrence after radiotherapy (RT). We performed spatial expression analyses, providing a rationale for dual inhibition of two non-redundant, spatially distinct acting factors, CXCL12 and VEGF. Subsequently, we expanded a multicentric phase 1/2 trial (NCT04121455), which initially combined RT and the CXCL12-neutralizing L-RNA-aptamer olaptesed pegol (NOX-A12) in patients with incompletely resected, newly-diagnosed GBM lacking MGMT promoter methylation. The primary endpoint was safety, secondary endpoints included maximum tolerable dose, recommended phase 2 dose, NOX-A12 plasma levels, topography of recurrence, tumor vascularization, neurologic assessment in neuro-oncology (NANO), quality of life, median progression-free survival (PFS), 6-months PFS and overall survival (OS). For the expansion arm, six patients were included that additionally received the VEGF-targeting antibody bevacizumab (BEV) to RT and NOX-A12. Combinatory treatment was well-tolerated and safe with no treatment-related deaths, resulting in abrogated tumor perfusion (rCBV, FTB) and delayed tumor regrowth as per mRANO. Median progression-free (PFS) and overall survival (OS) after RT + BEV + NOX-A12 were 9.1 and 19.9 months, respectively, significantly outperforming RT + NOX-A12 (p = 0.009; p = 0.021) in a post-hoc comparative analysis, with two patients exceeding 2-year OS. These findings establish proof-of-principle for dual inhibition of CXCL12 and VEGF in patients with newly-diagnosed GBM following RT.