Preliminary Treatment Study of ²¹¹At and ¹³¹I Labeled Nimotuzumab in Tumor-bearing Mice

Using nimotuzumab targeting epidermal growth factor receptor (EGFR) as carrier, we have established a one-step labeling process for ²¹¹At and ¹³¹I and performed a preliminary treatment study on tumor-bearing mice. The labeling rate both were about 95%, and related radiolabeling complexes could maintain stability in PBS and FBS. The distribution showed that tumor uptake was still maintained to （28.2±4.7） %ID·g^-1 after 24 h at intratumoral injection. The therapeutic effect of ¹³¹I/²¹¹At -ATE-nimotuzumab in U87MG glioma-bearing nude mice was further evaluated. The two labeled drugs can significantly inhibit the growth of solid tumors in a dose-dependent manner with no significant effect on the body weight of mice, effectively prolonging the survival time of subjects. In comparison, the median survival time of tumor-bearing mice in the ²¹¹At-ATE-nimotuzumab group at 20 μCi was longer than that in the ¹³¹I-ATE-nimotuzumab group at 20 μCi (35 days and 31.6 days). This work further confirmed that the α-nuclide ²¹¹At has great potential in the research of radioactive targeted therapy, and can provide an important reference for the preclinical basic research of related drugs.