TC-99M-F(AB)2 Instant Kits for Radioimmunoscintigraphy
Small Business Information
300 American Road, Morris Plains, NJ, 07950
Gary L. Griffiths
AbstractThe goal is to develop the optimum clinical agent for radioimmunoscintigraphy. The optimum nuclide is undoubtedly technetium- 99m. Comparing IgG-SH, F(ab')2-SH and Fab'-SH, it is expected that a F(ab')2-SH fragment will have fast enough clearance from circulation to permit earlier imaging than a comparably radiolabeled IgG-SH, while having less renal uptake than a comparably labeled Fab'-SH fragment. Previously, direct labeling of F(ab')2-SH was problematic in that a 50:50 mixture of Tc-99m-F(ab')2 and Tc99m-Fab' would result due to the presence of a small amount of monovalent fragment. We have a novel technique of pre.reducing intact IgG to break non-hinge region disulfide bonds prior to digestion of antibody. The resulting, pure F(ab')2-SH is capable of quantitative incorporation of technetium-99m, in the same manner as IgG-SH and Fab'-SH, are currently labeled to yield quantitatively Tc-99m-F(ab')2. We will extend the technique to different antibodies targeted against different cancers, and ultimately use humanized F(ab')2-SH fragments. In phase l research, we will prove the superiority of Tc99m-F(ab')2 over Tc-99m- Fab' and Tc-99m-IgG as an early time-point radioimmunoimaging agent; if successful, produce clinically usable kits at the conclusion of the Phase II period.
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