While improving cell growth and viral productivity in USP, DSP may become the production bottleneck if not able to withstand changes. Such a case appears when optimizing cell culture media during the development of a viral vaccine candidate. Thirty percent expression increased was balanced by twenty percent yield loss and filters clogging during the clarification step. As a consequence, clarification sequence was not scalable anymore for the further manufacturing. The poster describes sanofi pasteur approach to overcome this issue and…