TriTECM: A tetrafunctional T-cell engaging antibody with built-in risk mitigation of cytokine release syndrome

Abstract

Harnessing the innate power of T cells for therapeutic benefit has seen many shortcomings due to cytotoxicity in the past, but still remains a very attractive mechanism of action for immune-modulating biotherapeutics. With the intent of expanding the therapeutic window for T-cell targeting biotherapeutics, we present an attenuated trispecific T-cell engager (TCE) combined with an anti- interleukin 6 receptor (IL-6R) binding moiety in order to modulate cytokine activity (TriTECM). Overshooting cytokine release, culminating in cytokine release syndrome (CRS), is one of the severest adverse effects observed with T-cell immunotherapies, where the IL-6/IL-6R axis is known to play a pivotal role. By targeting two tumour-associated antigens, epidermal growth factor receptor (EGFR) and programmed death ligand 1 (PD-L1), simultaneously with a bispecific two-in-one antibody, high tumour selectivity together with checkpoint inhibition was achieved. We generated tetrafunctional molecules that contained additional CD3- and IL-6R-binding modules. Ligand competition for both PD-L1 and IL-6R as well as inhibition of both EGF- and IL-6-mediated signalling pathways was observed. Furthermore, TriTECM molecules were able to activate T cells and trigger T-cell-mediated cytotoxicity through CD3-binding in an attenuated fashion. A decrease in pro-inflammatory cytokine interferon γ (IFNγ) after T-cell activation was observed for the TriTECM molecules compared to their respective controls lacking IL-6R binding, hinting at a successful attenuation and potential modulation via IL-6R. As IL-6 is a key player in cytokine release syndrome as well as being implicated in enhancing tumour progression, such molecule designs could reduce side effects and cytotoxicity observed with previous TCEs and widen their therapeutic windows.

Targeting human γδ T cells as a potent and safe alternative to pan-T cells bispecific cell engagers

“…Higher grade CRS is most often manageable but requires patient hospitalization and can be life-threatening for the patient [52][53][54] . Recent engineering strategies aim at decreasing CD3 binding domain affinities or designing conditionally active TCEs [55][56][57][58][59] . An alternative strategy to improve the safety profile of bispecific TCEs while keeping high antitumor activity is to selectively recruit highly cytotoxic T cell subsets such as γδ T cells rather than indiscriminately recruit all T cells (reviewed in 60,61 ).…”

When three is not a crowd: trispecific antibodies for enhanced cancer immunotherapy

“…In both cases, TriTECM antibodies inhibited simultaneously and dose-dependently EGFR and IL6R signaling pathways and triggered efficiently T cell activation and cytotoxicity against EGFR+ cells. In addition, TriTECM-mediated antitumor T cell activity was attenuated in comparison with EGFR/PD-L1/CD3 TsAb variants, indicating TriTECM potential as TCE with cytokine release modulator activity 90 .…”

Bridging the gap with multispecific immune cell engagers in cancer and infectious diseases

“…The first-in-class tetrafunctional T-cell engager was reported in 2022, in which a fourth arm containing an anti-IL-6 receptor (IL-6R) was added to an anti-EGFR x anti-PDL1 × anti-CD3 agent to modulate the activity of this cytokine and decrease cytokine release syndrome [ 23 ]. The authors showed attenuated IFN-γ production while maintaining sufficient T-cell-mediated cytotoxicity against cancer cells.…”

“…The authors showed attenuated IFN-γ production while maintaining sufficient T-cell-mediated cytotoxicity against cancer cells. This new strategy has the ability to modulate cytokine storms, an unfortunate side effect often observed with T-cell immunotherapy, although the release of other proinflammatory cytokines still needs further investigation [ 23 ].…”