Contents 4 How to Utilize Design of Experiment (DoE) Principles for Developing Robust Analytical Methods for QC Environments by Jeremy Springall, PhD 10 Validation Guidance for Residual Host Cell DNA Testing of Biologics by Mike Brewer 16 Critical Quality Attributes Assessment and Testing Strategy for Biotherapeutics Development by Christine P. Chan 22 Validation of a Duplex qPCR Assay to Detect Residual Sf9 Host Cell DNA and Baculovirus DNA by Dr. Kara Norman 32 Exposure Based Limits for Controlling Impurities by D.P. Elder 2