bevacizumab + irinotecan + radiotherapy + temozolomide

This is a combination therapy regimen used primarily in the treatment of glioblastoma (GBM), an aggressive primary brain tumor. The regimen includes: - Bevacizumab, a humanized monoclonal antibody that binds to vascular endothelial growth factor A (VEGF-A) and inhibits angiogenesis. - Irinotecan, a small molecule topoisomerase I inhibitor that interferes with DNA replication in cancer cells. - Temozolomide, an oral alkylating agent that induces DNA damage leading to cell death. - Radiotherapy, which uses ionizing radiation to kill tumor cells. The combination is typically administered as follows for newly diagnosed GBM patients: 1. Standard radiation therapy with daily temozolomide and bevacizumab. 2. After completion of radiotherapy, adjuvant cycles of temozolomide are given together with bevacizumab and irinotecan. Bevacizumab targets VEGF-mediated angiogenesis; irinotecan disrupts DNA replication via topoisomerase I inhibition; temozolomide causes cytotoxic methylation of DNA; radiotherapy damages cellular DNA directly. This multi-modal approach aims to improve survival outcomes by targeting both tumor proliferation and its blood supply[1][2][5][6].