Regression of lymphoma xenografts after conventional or pretargeted RIT.
(A) Conventional RIT. Six- to 10-week-old BALB/c nude mice bearing Ramos lymphoma xenografts were injected intraperitoneally with either 800 μCi 90Y-biotin alone (▵), 1.4 nmol control conjugate NR-LU-10-SA, followed 24 hours later by 5.8 nmol CA and 3 hours after that with 800 μCi 90Y-DOTA-biotin (▴), or with 1.4 nmol directly radiolabeled 90Y-DOTA-1F5 labeled with either 200 μCi (■) or 400 μCi of 90Y (▪). (B) Pretargeted RIT. Six- to 10-week-old BALB/c nude mice bearing Ramos lymphoma xenografts were injected intraperitoneally with 1.4 nmol anti-CD20 immunoconjugate 1F5-SA, followed 24 hours later by 5.8 nmol CA, and 3 hours after that with either 400 μCi (○) or 800 μCi (●) 90Y-DOTA-biotin. Notice the differences in the scales of both the tumor size and the time axes between panels A and B.
