A U.S. Patent for “On-Column Viral Inactivation Methods”  was awarded to Sanofi  on April 7th, 2020.  The present invention is a method of inactivating a virus present during production of a polypeptide of interest, the method comprising the following sequential steps: (a) binding the polypeptide to a chromatography matrix, (b) washing the polypeptide-bound chromatography matrix of step (a) with a first wash solution comprising a salt at a pH above 6.5, (c) washing the polypeptide-bound chromatography matrix of step (b) with a second wash solution comprising a salt at a concentration greater than about 0.5 M… Learn More