The engineering of monoclonal antibodies has created a new generation of
pharmaceuticals with the desired pharmacokinetics and biodistribution properties. For
radioimmunotherapy and radioscintigraphy, optimum tumor targeting can be achieved using
engineered constructs that provide high antigen affinity and specificity, effective tumor
penetration, circulation properties that allow high tumor uptake with acceptable doses to the
normal tissues, and fast clearance allowing low background. Recent advances have made …

Monoclonal antibodies (MAbs), because of their inherent specificity, are ideal targeting
agents. They can be used to deliver radionuclides, toxins or cytotoxic drugs to a specific
tissue or malignant cell populations. Intact immunoglobulin (IgG) molecules have several
practical limitations of their pharmacology; their relatively large size of approximately
150,000 daltons leads to a slow clearance from the blood pool and the body resulting in
significant exposure to normal organs with limited quantities delivered to tumors. The IgG …