Generación y caracterización de fragmentos de anticuerpo recombinantes multiespecíficos para inmunoterapia del cáncer

Resum

In the last decades, biespecific antibodies (BsAb) have shown a great therapeutic potential in cancer, leading to the approval of blinatumomab for acute lymphoblastic leukemia treatment (2014) and amivantamab for non-small cell lung cancer (2021). In spite of the increasing number of BsAb in development, their therapeutic use has revealed limitations related to efficacy and safety. Here, we describe and characterize a new trispecific antibody (TsAb) format, named TriTE (Trispecific T-cell Engager), which redirects T cell response toward colorectal cancer (CRC) cells. The TriTE antibody consists of two anti-EGFR and anti-EpCAM single-domain VHH antibodies fused to an anti-CD3 scFv (single-chain Fv) antibody fragment. This antibody, which is efficiently expressed by mammalian and yeast cells, is able to recognize its target antigens on the cell surface, as well as trigger specific cytotoxic T cell response against EGFR- and/or EpCAM-expressing CRC cells, although to a lesser extent in those which express a single tumor-associated antigen (TAA). In vitro, specific cytolysis of double-positive CRC cells induced by TriTE was at least 20-fold stronger compared to that of single-positive CRC cells. Moreover, TriTE was able to delay the tumor growth and significantly increased survival in vivo. A higher specificity and a better safety profile of TriTE regarding conventional BsAb are expected, since double-negative CRC cells were spared and the killing of single-positive cells was limited. In addition, the dual targeting of two different TAA can decrease the risk of tumor scape due to intratumor antigenic heterogeneity or antigen loss associated to selective pressure by BsAb-based therapies...