Recently in Washington, DC, two conferences were held on the topics of cell and gene therapy. The California Separation Science Society (CASSS, www.casss.org) hosted a Well-Characterized Biological Products (WCBP) Chemicals, Materials, and Controls (CMC) strategy forum on “Current Practices for Assessing the Comparability and Stability of Gene Therapy Products,” while blocks away, Phacilitate hosted the 2008 Cell and Gene Therapy forum. At the WCBP CMC strategy forum, participants heard the US FDA–CBER perspective on the importance of comparability studies for…