101 Expansion of tumor-infiltrating lymphocytes (TIL) using static bag for the clinical manufacturing rapid expansion protocol (REP) process (2021)

<h3>Background</h3> Lifileucel (LN-144) and LN-145, adoptive cell therapies using autologous tumor-infiltrating lymphocytes (TIL), have demonstrated encouraging efficacy with acceptable safety in a variety of tumor types.<sup>1–4</sup> The lifileucel Gen 2 clinical manufacturing process uses gas-permeable rapid expansion (G-Rex®, Wilson Wolf, Saint Paul, MN) bioreactors for TIL expansion.<sup>5</sup> Static gas-permeable cell culture bags (EXP-Pak™, Charter Medical, Winston-Salem, NC) are alternate bioreactors that have been used for clinical manufacturing of T cells.<sup>6</sup> In this study, TIL product characteristics were compared after expansion at small- and full-scale using EXP-Pak bags and G-Rex bioreactors. <h3>Methods</h3> Cryopreserved pre-REP TIL were cultured with OKT-3 and irradiated peripheral blood mononuclear cells in either small-scale (G-Rex 5M flasks or EXP-50 bags) or full-scale (G-Rex 500MCS or EXP-5L bags) conditions. The same culture media formulation was used throughout the process. Final harvested TIL products were characterized for the following quality attributes: total viable cells (TVC), purity (% viability), identity (% CD45<sup>+</sup>CD3<sup>+</sup>), and activity (IFN-gamma release). Additional characterization was performed to determine the TIL differentiation, central and effector memory subsets, activation, exhaustion status, and impurities using multi-color flow cytometry. The T-cell receptor (TCR) repertoires of the final products were assessed for unique CDR3 (uCDR3) counts and shared clones using RNA-seq. <h3>Results</h3> The median (range) TVC from 6 small-scale runs of G-Rex condition was 90.8×10<sup>9</sup> (26.9×10<sup>9</sup>–98.6×10<sup>9</sup>) cells, and the corresponding TVC of EXP-Pak bag condition was 119×10<sup>9</sup> (63.2×10<sup>9</sup>–141×10<sup>9</sup>) cells. Full-scale runs (n=3) yielded similar TVC for G-Rex and EXP-Pak bag conditions. Both conditions had comparable purity, identity, and activity (table 1). 91–99% of TCR Vbeta clones of EXP-Pak bag TIL were present in G-Rex (table 2). Cell proliferation, cell cycle, and mitochondrial function of TIL generated from EXP-Pak bags and G-Rex flask methodologies will be presented. <h3>Conclusions</h3> The final TIL product generated in the EXP-Pak bag condition did not differ from cells produced in the G-Rex flask functionally or phenotypically and demonstrated similar growth profiles. These data support further evaluation of EXP-Pak bags for potential use in clinical and potential commercial TIL cell therapy manufacturing applications. <h3>Acknowledgements</h3> This study and analysis were funded by Iovance Biotherapeutics, Inc. (San Carlos, CA, USA). Editorial support was provided by Amanda Kelly (Iovance). <h3>References</h3> Sarnaik AA, et al. <i>J Clin Oncol</i>. 2021; doi: 10.1200/JCO.21.00612. Thomas SS, et al. <i>J Clin Oncol</i>. 2021;39 (suppl; abstract 9537). Jazaeri A, et al. <i>J Clin Oncol</i>. 2019;37 (suppl; abstract 2538). Jimeno A, et al. <i>J Immunother Cancer</i>. 2020;8 (suppl; abstract A378). Wardell S, et al. <i>J Immunother Cancer</i>. 2019;7 (suppl 1; abstract P226). BioProcess International. 2014 [white paper]. https://bioprocessintl.com/sponsored-content/efficacy-utility-new-exp-pak-closed-system-disposable-cell-expansion-bags-designed-cell-therapy-applications/Accessed July 23, 2021.