The analytical program for a given biotherapeutic has a life-cycle analogous to that of a manufacturing process used to prepare material for clinical and commercial use. This two-part article discusses analytical activities associated with the progression of biotherapeutic candidates from the early stages of clinical development through their appearance as licensed drugs on the market. In Part One, we examined the stages of the analytical life-cycle. Here we conclude by going into more detail on challenges associated with method qualification,…