A U.S. Patent for a “Method of Cell Culture” was awarded to Pfizer on January 28th, 2020. The present invention isa method of cell culture comprising (i) providing cells in a cell culture medium to start a fed-batch cell culture process, and, (ii) maintaining at least one metabolite selected from 3-(4-hydroxyphenyl)lactate, 4-hydroxyphenyl pyruvate, phenyllactate, indolelactate, indolecarboxylic acid, homocysteine, 2-hydroxybutyric acid, isovalerate and formate below a concentration C1 in the cell culture medium, wherein C1 is 3mM, wherein maintaining the at least one metabolite below a concentration C1 in the cell culture comprises. Learn More