Ec. Barendswaard et al., Relative therapeutic efficacy of I-125- and I-131-labeled monoclonal antibody A33 in a human colon cancer xenograft, J NUCL MED, 42(8), 2001, pp. 1251-1256
Citations number
18
Categorie Soggetti
Radiology ,Nuclear Medicine & Imaging","Medical Research Diagnosis & Treatment
A33, a monoclonal antibody that targets colon carcinomas, was labeled with
I-125 or I-131 and the relative therapeutic efficacy of the 2 radiolabeled
species was compared in a human colon cancer xenograft system. Methods: Nud
e mice bearing human SW1222 colon carcinoma xenografts were administered es
calating activities of I-125-A33 (9.25-148 MBq) or I-131-A33 (0.925-18.5 MB
q), I-125- and I-131-labeled control antibodies, unlabeled antibody, or no
antibody. The effects of treatment were assessed using the endpoints of tum
or growth delay and cure. Results: Tumor growth delay increased with admini
stered activity for all radiolabeled antibodies. Approximately 4.5 times mo
re activity was required for I-125-A33 to produce therapeutic effects that
were equivalent to those of I-131-A33. This ratio was approximately 7 for a
nonspecific, noninternalizing isotype-matched, radiolabeled control antibo
dy. Unlabeled A33 antibody had no effect on tumor growth. Approximately 10
times more activity of I-125-A33 produced toxicity similar to that of I-131
-A33, and this ratio fell to approximately 6 for radiolabeled control antib
ody. Conclusion: Treatment with I-125-A33 resulted in a relative therapeuti
c gain of approximately 2 compared with I-131-A33 in this experimental syst
em.