# Bio-functional hydrogel coated membranes to decrease T-cell exhaustion in manufacturing of CAR T-cells

## TL;DR

This paper introduces a new method using hydrogel-coated membranes to reduce T-cell exhaustion during CAR T-cell manufacturing, leading to better cell therapy outcomes.

## Contribution

A novel bioinspired platform using hydrogel-coated membranes is proposed to control T-cell activation and reduce exhaustion during CAR T-cell production.

## Key findings

- T cells cultured on hydrogel-coated membranes showed memory phenotypes and minimal exhaustion.
- CAR T cells produced with hydrogel-coated membranes exhibited improved in vitro cytolysis with lower variability.
- Hydrogel-coated membranes increased T-cell transduction and reduced exhaustion compared to standard methods.

## Abstract

Cell therapies have revolutionized cancer treatment, with chimeric antigen receptor (CAR) T-cell therapies at the forefront for the treatment of hematological cancers. However, current manufacturing protocols rely on rapid T-cell activation, which can induce exhaustion and undesirable phenotypes, ultimately reducing the efficacy and persistence of CAR T-cells. Given the importance of T-cell activation as a fundamental step to achieve proliferative phenotypes for cell engineering and expansion, approaches are needed to control activation and increase CAR T-cell quality. To address this need, in this work, we utilized a bioinspired, scalable, tunable platform to direct T-cell activation and decrease exhaustion during CAR T production.

Hydrogel-coated membranes (HCMs) were designed with different co-stimulatory ligands and a physiologically-relevant substrate modulus inspired by the native microenvironment in which T cells are programmed. Phenotype, activation, and exhaustion markers were used to compare T cells cultured with HCMs or industry standard TransAct. Next, transduction with a CD19 CAR lentivirus was performed, and the killing potential of the resulting CAR T product was evaluated using an in vitro cytolysis model.

With this controlled and well-defined system, we hypothesized that a combination of ligands inspired by antigen-presenting cells would promote desired T-cell phenotypes with reduced exhaustion and thereby improved killing efficacy. We found memory phenotypes, minimal exhaustion, and similar activation profiles with HCMs. Additionally, increased T-cell transduction and decreased exhaustion for the CAR T population were observed with HCMs. Further, the killing potential of the resulting CAR T product was evaluated, finding improved in vitro cytolysis of target cells with lower variability with HCMs.

These results demonstrate the importance of lower T-cell exhaustion in CAR T manufacturing and present significant opportunities to modulate T-cell phenotypes for cell therapy applications using engineered bioinspired materials that display combinations of co-stimulatory molecules.