Leveraging T cell co-stimulation for enhanced therapeutic efficacy of trispecific antibodies targeting prostate cancer.

backgroundClinical trials have demonstrated the efficacy of bispecific antibodies in eliciting potent antitumor responses by redirecting T cells to target cancer cells, particularly for the treatment of hematologic malignancies. However, their efficacy against solid tumors is limited by intratumoral T-cell dysfunction and inadequate persistence. The co-stimulatory domains of 4-1BB, OX40, and CD28 are most widely used in engineering chimeric antigen receptor T-cells to augment T-cell responses.

methodsIn this study, we designed three co-stimulatory trispecific T cell-engaging antibodies (TriTCEs) that target Prostate-specific membrane antigen, CD3, and an additional co-stimulatory receptor(OX40, 4-1BB, or CD28). We conducted comparative profiling of the attributes of distinct co-stimulatory signals to T-cell functions in prostate cancer models.

resultsCo-stimulatory trispecific T-cell engagers enhance T-cell activation, proliferation, and display tumor cell-killing activity in vitro. These trispecific antibodies further boosted antitumor activity in humanized mouse xenograft models and increased the infiltration of CD45

conclusionsCollectively, incorporating co-stimulatory receptor targeting domains represents a potentially effective strategy to unlock the full therapeutic potential of T-cell-engaging antibodies for the treatment of solid tumors.