As described in ICH Q5A on virus safety of biotechnological products (1) and the European guideline on virus safety of biotechnological products, EMEA 398498 (2), viral clearance studies are mandated as part of the viral safety evaluation of products derived from human or other mammalian cell lines. When acceptable ranges of process parameters are known, both guidelines recommend that scale-down models be evaluated under worst-case conditions for viral clearance. The BioPhorum Development Group’s viral clearance workstream performed a benchmarking survey…