CYTOTOXIC AGENTS BEARING A REACTIVE POLYETHYLENE GLYCOL MOIETY, CYTOTOXIC CONJUGATES COMPRISING POLYETHYLENE GLYCOL LINKING GROUPS, AND METHODS OF MAKING AND USING THE SAME
Cytotoxic agents bearing a polyethylene glycol (PEG) linking group having a terminal active ester, cytotoxic conjugates comprising one or more cytotoxic agents linked to a cell-binding agent via PEG linking groups, and methods for producing both are disclosed. A therapeutic composition comprising a therapeutically-effective amount of one of the cytotoxic conjugates of the present invention, and a method of killing selected cell populations comprising contacting target cells, or tissue containing target cells, with an effective amount of one of the cytotoxic conjugates, are also disclosed.