Joseph P Balthasar

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More than 20 monoclonal antibodies have been approved as therapeutic drugs by the US Food and Drug Administration, and it is quite likely that the number of approved antibodies will double in the next 7-10 years. Antibody drugs show several desirable characteristics, including good solubility and stability, long persistence in the body, high selectivity and(More)
Although it is known that FcRn, the neonatal Fc-receptor, functions to protect immune gamma globulin (IgG) from elimination, the influence of FcRn on the tissue distribution of IgG has not been quantified. In the present work, a physiologically-based pharmacokinetic (PBPK) model has been developed to characterize and predict IgG disposition in plasma and in(More)
The U.S. Food and Drug administration (FDA) has approved several polyclonal antibody preparations and at least 18 monoclonal antibody preparations (antibodies, antibody fragments, antibody fusion proteins, etc.). These drugs, which may be considered as a diverse group of therapeutic proteins, are associated with several interesting pharmacokinetic(More)
The time course of chemotherapeutic effect is often delayed relative to the time course of chemotherapeutic exposure. In many cases, this delay is difficult to characterize mathematically through the use of standard pharmacodynamic models. In the present work, we investigated the relationship between methotrexate (MTX) exposure and the time course of MTX(More)
Recently, our laboratory reported that intravenous immunoglobulin (IVIG) treatment increased antiplatelet antibody (7E3) clearance in a rat model of immune thrombocytopenic purpura (ITP). However, due to the multifaceted nature of IVIG therapy, the contribution of this increase in antiplatelet antibody clearance to the total therapeutic effect of IVIG was(More)
Antibodies directed against tumor associated antigens are being increasingly used for detection and treatment of cancers; however, there is an incomplete understanding of the physiological determinants of antibody pharmacokinetics and tumor distribution. The purpose of this study is to (a) compare the plasma pharmacokinetics of T84.66, a monoclonal anti-CEA(More)
We have recently shown that intravenous immunoglobulin (IVIG) therapy leads to an increased rate of anti-platelet antibody clearance in an animal model of immune thrombocytopenia. The present study was performed to confirm the importance of the FcRn receptor in mediating this effect of IVIG. The pharmacokinetics of an anti-platelet antibody, 7E3, were(More)
Minimal physiologically-based pharmacokinetic (mPBPK) models provide a sensible modeling approach when fitting only plasma (or blood) data yielding physiologically-relevant PK parameters that may provide more practical value than parameters of mammillary models. We propose a second-generation mPBPK model specifically for monoclonal antibodies (mAb) by(More)
Efforts have been made to extend the biological half-life of monoclonal antibody drugs (mAbs) by increasing the affinity of mAb–neonatal Fc receptor (FcRn) binding; however, mixed results have been reported. One possible reason for a poor correlation between the equilibrium affinity of mAb–FcRn binding and mAb systemic pharmacokinetics is that the(More)
It has been suggested that the neonatal Fc receptor (FcRn) is a primary determinant of the distribution of IgG to the brain. In the present report, 125I-labeled 7E3, a monoclonal IgG1 antibody, was injected intravenously to groups of FcRn-deficient mice and C57BL/6J control mice. Sub-groups of three mice were sacrificed at several time points. Blood and(More)