New Perfusion Filter Demonstrates Improved Cell Retention When Expanding Human T Cells In Xuri™ Cell Expansion System

By Sabrina Carmichael, Trevor Smith, and Elisaveta Todorova, Cytiva

Xuri™ brand Perfusion Cellbag™ bioreactors (previously known as WAVE™ Bioprocess Cellbag bioreactors) are regularly used for ex vivo T cell expansion in chimeric antigen receptor (CAR) T cell therapy manufacturing. The WAVE™ brand Cellbag™ bioreactor, with a filter membrane of 7–12 μm average pore size, was designed to expand cells used in bioprocess applications. Because T cells are 7–13 μm on average, using these bags for perfusion-based T cell expansion resulted in cell loss, decreased cell retention, and inability for further expansion to the desired cell density. Therefore, a new perfusion filter membrane was developed specifically for T cell expansion. The new 1.2 μm pore size filter was validated for use in the Xuri™ Cell Expansion System W25, which consists of a reusable instrument and single-use Cellbag™ bioreactors. The substantially smaller pore size of the new filter membrane decreased T cell loss, ultimately leading to higher T cell retention in the Xuri™ brand Cellbag™ bioreactor. These results can correlate to attaining the dosing density of a given cell therapy quicker compared to using a larger pore size filter, which could decrease the processing time for cell therapy manufacturers. A decreased processing time could also reduce the cost of the therapy.