A rapid increase in the number of gene therapy trials and products has led to a comparable increase in the need for industrial production of viral gene therapy vectors such as lentiviral, adeno-associated, and adenoviral vectors. Current production systems are limited with respect to scalability and robustness. With our CAP® and CAP-T™ cell lines, we have developed a novel system for high-density suspension culture, efficient and reproducible transfection, and highly efficient production of viral vectors. By upstream process optimization, we have obtained a robust and high-density fed-batch culture system which can be scaled in any current bioreactor format. A design-of-experiments approach has been employed to optimize transient production of lentiviral vectors with significantly higher titers than can be obtained with adherent HEK293T cells…