Patent ID: 8741291

Claim:
A composition comprising a multifunctional antibody conjugate (MAC), the MAC comprising (i) an antibody or antigen binding portion thereof, comprising at least a fragment of a light chain constant kappa region (CLκ) comprising K 188 according to Kabat numbering; (ii) a linker comprising the formula X-Y-Z, wherein Z is a group of formula and is covalently connected to the antibody through the ε-amino group of the side chain of K 188 , Y is a linear or branched biologically compatible connecting chain, and X is a group covalently connected to at least one Effector Moiety, and pharmaceutically acceptable salts, stereoisomers, tautomers, solvates, and prodrugs thereof, wherein the MAC is prepared by covalently attaching the Effector Moiety to a linker terminating in an activated ester with a leaving group Z* of the formula: where R 1 is F, and h=3, 4 or 5, and reacting the Effector Moiety-Linker-Z* complex so formed with the antibody, wherein at least about 50% of the Effector Moiety in the composition or sample is conjugated to K188-CLK.