The European Medicines Agency (EMA) has approved 3 recombinant viral vector products: Glybera (UniQure, Amsterdam, The Netherlands), an rAAV vector for lipoprotein lipase deficiency; Strimvelis (Glaxo Smith-Kline, Brentford, United Kingdom), an <i>ex vivo</i> gammaretrovirus-based therapy for patients with adenosine deaminase-deficient severe combined immune deficiency (ADA-SCID); and Kymriah (Novartis, Basel, Switzerland), an <i>ex vivo</i> lentivirus-based therapy to engineer autologous chimeric antigen-receptor T (CAR-T) cells targeting CD19-positive cells in acute lymphoblastic leukemia.