As viruses can arise during the manufacture of biopharmaceuticals, regulatory agencies require “viral clearance” validation studies for each biopharmaceutical prior to approval. For example, Type C Retrovirus-Like Particles (RVLP) are endogenously produced during CHO cell expression. As such, regulatory agencies require proof that downstream process steps can effectively remove or inactivate retrovirus. A model mammalian virus, Xenotropic Murine Leukemia Virus (XMuLV) is typically used to demonstrate RVLP clearance. However, the establishment of RVLP quantification methods has made it possible to…