Combined treatment of glioblastoma patients with locoregional pre-targeted 90Y-biotin radioimmunotherapy and temozolomide.

Aim. In a previous phase I-II study, the safety profile and anti-tumor efficacy of pre-targeting locoregional radioimmunotherapy (LR-RIT), based on the “3 step” method, was assessed in 24 high-grade glioma patients. The encouraging results in terms of low toxicity and objective response rate (25%) prompted us to continue our study. Methods. An analysis of 73 patients with hystologically confirmed glioblastoma multiforme (GBM), treated with the “3 step” 90Y-biotin based LR-RIT, is herein reported. All patients had a catheter implanted at 2nd surgery and underwent at least 2 cycles of LR-RIT (range 2-7) with 2 months interval. Thirty-five out of 73 patients were also treated with Temozolomide (TMZ). Two cycles of TMZ (200 mg/m2/day, for 5/28 days) were administered in between each course of LR-RIT. Overall survival (OS) and progression free survival (PFS) were retrospectively calculated. Results. Stabilization of disease was achieved in 75% of patients, while 25% progressed. In the 38 patients treated with LR-RIT alone, median OS and PFS were respectively 17.5 months (95%CI=[17-20]) and 5 months (95%CI=[4-8]), while in the 35 treated with the combined treatment (LR-RIT+TMZ) respective values were 25 months (95%CI=[23-30]) and 10 months (95%CI=[9-18] (p<0.01). The addition of TMZ to LR-RIT did not increase neurological toxicity, and no major hematological toxicity was observed. Conclusion. These results confirm the safety and the efficacy of 90Y LR-RIT in recurrent GBM patients; the addition of TMZ significantly improved the overall out