PHARMACOKINETICS, BIODISTRIBUTION AND TUMOR-LOCALIZATION OF 2 ANTI-HUMAN B-CELL CHRONIC LYMPHOCYTIC-LEUKEMIA MONOCLONAL-ANTIBODIES AND THEIR F(AB)'(2) FRAGMENTS IN A XENOGRAFT MODEL

We investigated the pharmacokinetics, biodistribution and tumor locali zation of intravenously injected Dal B01 and Dal B02, two monoclonal a ntibodies (MoAbs) directed against tumor associated antigens on human chronic lymphocytic leukemia (CLL) B cells, and their F(ab)'(2) fragme nts in nude mice bearing xenografts of the human B cell CLL line D-10- 1. More of the percentages of the injected dose (% ID) of these two Mo Abs and their F(ab)'(2) fragments specifically localized in the tumor xenografts than in normal tissues. Compared to intact MoAbs, their F(a b)'(2) fragments had lower % ID in tumors and were cleared from circul ation faster. Well-defined tumor images were obtained at 24 and 48 h a fter administration of [I-131]Dal B02 F(ab)'(2) fragment and at 96-192 h after administration of [I-131]Dal B02. A comparison between intrav enous and intraperitoneal routes of administration of [I-131]Dal B02 d id not reveal any difference in the localization of % ID in tumor or n ormal tissues.