Fuente: WIPO "tomato" The present invention provides a continuous upstream manufacturing process for the production of bispecific antibody products, which comprise at least two binding domains. The process comprises at least the steps of (i) providing in a perfusion bioreactor at least one mammalian cell culture, which is capable of expressing the bispecific antibody product, (ii) growing the mammalian cell culture at a first perfusion rate until a set point viable cell density is reached, and (iii) maintaining perfusion culture at a second perfusion rate, wherein the bispecific antibody product concentration in the bioreactor is kept below a threshold value. The bispecific antibody product is then subject to subsequent downstream processing. Moreover, the invention provides a bispecific antibody product produced by the continuous upstream manufacturing process.