Patent ID: 8383122
Filing Date: 2013-02-26
Classification: A61K,A61P,C07K

Abstract:
1. A process for preparing a cell-binding agent-cytotoxic agent conjugate comprising the steps of: (a) contacting a cell-binding agent with a bifunctional crosslinking reagent to covalently attach a linker to the cell-binding agent and thereby prepare a first mixture comprising cell-binding agents having linkers bound thereto, (b) subjecting the first mixture to selective precipitation, adsorptive filtration, or adsorptive chromatography and thereby prepare a purified first mixture of cell-binding agents having linkers bound thereto, (c) conjugating a cytotoxic agent to the cell-binding agents having linkers bound thereto in the purified first mixture by reacting the cell-binding agents having linkers bound thereto with a cytotoxic agent in a solution having a pH of about 4 to about 9 to prepare a second mixture comprising (i) cell-binding agent chemically coupled through the linker to the cytotoxic agent, (ii) free cytotoxic agent, and (iii) reaction by-products, and (d) subjecting the second mixture to tangential flow filtration to purify the cell-binding agents chemically coupled through the linkers to the cytotoxic agent from the other components of the second mixture and thereby prepare a purified second mixture of cell-binding agents chemically coupled through the linkers to the cytotoxic agent.