Centocor, Inc.

Raymond H Boutin

Richard T Dean

Robert W Weber

John Lister-James

A bifunctional coupling agent for joining a sulfhydryl-containing protein or peptide and a metallic radionuclide comprising a sulfhydryl selective electrophile, a chelator containing at least one protected thiol and a organic linking radical which serves to join said electrophile and said chelator is disclosed. A radiodiagnostic precursor comprising an antibody or antibody fragment and the specified bifunctional coupling agent bound to a sulfhydryl group on the antibody or antibody fragment is also disclosed.

Bifunctional coupling agents and radionuclide labeled compositions

The present invention provides cross-linked protein compositions consisting of two or more units of a target-specific protein joined by binding sulfhydryl groups on the target-specific protein units to a sulfhydryl-selective cross-linking agent and a method of making the compositions. These cross-linked protein compositions combine an increase in binding affinity due to the presence of multiple identical binding sites and stability to reduction conditions.

Cross-linking protein compositions having two or more identical binding

Protein conjugates comprising a protein covalently linked to at least one positively charged agent, so that the protein conjugate has an overall net positive charge in aqueous conditions at physiological pH are disclosed. The positively charged agents comprise polymers of three or more subunits selected from the group consisting of amino acids containing positively charged side chains and alkylamines. These protein conjugates have decreased blood clearance rates compared to conjugates which do not have the positively charged agents. The protein conjugates may further comprise diagnostic or therapeutic radionuclides bound to the protein or the positively charged agent through bifunctional coupling agents.

Proteins modified with positively charged carriers and compositions

A bifunctional coupling agent for joining a sulfhydryl containing protein or peptide and a metallic radionuclide comprising a sulfhydryl selective electrophile, a chelator containing at least one protected thiol and a organic linking radical containing at least one cleavable site which serves to join said electrophile and said chelator is disclosed. A radiodiagnostic or radiotherapeutic precursor comprising an antibody or antibody fragment and the specified bifunctional coupling agent bound to a sulfhydryl group on the antibody or antibody fragment and a radiodiagnostic or radiotherapeutic agent comprising such precursor having a metallic radionuclide bound thereto are also disclosed.

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Wilmington, DE, United States of America

Raymond H Boutin