Dose escalation therapeutic study of²¹³Bi–DOTA-biotin with the pretargeting technique in MET-1 tumor-bearing SCID/NOD mice.

At the time of the experiment, the mice had sIL-2Rα levels of 1000-10 000 pg/mL. The mice in the control group did not receive any treatment. Mice in other groups received 140 μg HAT-SA pretargeting for 24 hours, 100 μg sCA for 4 hours, and 0.3 μg²¹³Bi–DOTA-biotin at different doses of ²¹³Bi: 0 μCi (0 MBq; Bi-0), 50 μCi (1.85 MBq; Bi-50), 150 μCi (5.55 MBq; Bi-150), 250 μCi (9.25 MBq; Bi-250), or 350 μCi (12.95 MBq; Bi-350). Serum collections from the mice were taken at 3 days before and at 14 and 28 days after therapy. The serum concentrations of (A) sIL-2Rα, (B) β2M, and (C) Kaplan-Meier survival plot were shown. *P < .05, **P < .01 as compared with the control group.