Clinical StudyLarge-scale Clinical-grade Retroviral Vector Production in a Fixed-Bed BioreactorWang, Xiuyan*,†; Olszewska, Malgorzata*; Qu, Jinrong*; Wasielewska, Teresa*; Bartido, Shirley*; Hermetet, Gregory‡; Sadelain, Michel†,§; Rivière, Isabelle*,†,§Author Information *Cell Therapy and Cell Engineering Facility †Molecular Pharmacology and Chemistry Program §Center for Cell Engineering, Memorial Sloan Kettering Cancer Center, New York ‡Pall Life Sciences, Port Washington, NY Supplemental Digital Content is available for this article. Direct URL citations appear in the printed text and are provided in the HTML and PDF versions of this article on the journal's Website, www.immunotherapy-journal.com. X.W. and I.R.: designed the research plan; X.W., M.O., J.Q., T.W, G.H.: performed research; S.B. contributed to quality control testing; X.W., I.R., and M.S.: wrote the manuscript. Reprints: Isabelle Rivière, Memorial Sloan Kettering Cancer Center, 1275 York Ave, P.O. Box 182, New York, NY 10065. E-mail: email@example.com. Received October 20, 2014 Accepted January 5, 2015 Journal of Immunotherapy: April 2015 - Volume 38 - Issue 3 - p 127-135 doi: 10.1097/CJI.0000000000000072 Buy SDC Metrics Abstract The successful genetic engineering of patient T cells with γ-retroviral vectors expressing chimeric antigen receptors or T-cell receptors for phase II clinical trials and beyond requires the large-scale manufacture of high-titer vector stocks. The production of retroviral vectors from stable packaging cell lines using roller bottles or 10- to 40-layer cell factories is limited by a narrow harvest window, labor intensity, open-system operations, and the requirement for significant incubator space. To circumvent these shortcomings, we optimized the production of vector stocks in a disposable fixed-bed bioreactor using good manufacturing practice–grade packaging cell lines. High-titer vector stocks were harvested over 10 days, representing a much broader harvest window than the 3-day harvest afforded by cell factories. For PG13 and 293Vec packaging cells, the average vector titer and the vector stocks’ yield in the bioreactor were higher by 3.2- to 7.3-fold, and 5.6- to 13.1-fold, respectively, than those obtained in cell factories. The vector production was 10.4 and 18.6 times more efficient than in cell factories for PG13 and 293Vec cells, respectively. Furthermore, the vectors produced from the fixed-bed bioreactors passed the release test assays for clinical applications. Therefore, a single vector lot derived from 293Vec is suitable to transduce up to 500 patients cell doses in the context of large clinical trials using chimeric antigen receptors or T-cell receptors. These findings demonstrate for the first time that a robust fixed-bed bioreactor process can be used to produce γ-retroviral vector stocks scalable up to the commercialization phase. Copyright © 2015 Wolters Kluwer Health, Inc. All rights reserved.