BioAtla, Inc. announced that the U.S. Food and Drug Administration (FDA) has cleared its investigational new drug (IND) application to evaluate BA3182 (CAB-EpCAMxCAB-CD3 bispecific T-cell engager) for the treatment of advanced adenocarcinoma. BioAtla plans to initiate and advance a Phase 1 dose-escalation and expansion clinical study in 2023. The high-level expression of EpCAM in solid tumors has made it an attractive target for antibody molecules to treat epithelial cancers, particularly adenocarcinomas.

However, EpCAM is also highly prevalent on normal cells. EpCAM/CD3 bispecific antibodies developed by others have shown beneficial clinical outcomes in cancer patients, but have been hampered by dose limiting toxicities due to wide target distribution in normal tissues and potent T cell activation. In vitro studies have shown that dual CAB bispecific antibody, BA3182, binds to the target proteins, human EpCAM and human CD3, with high specificity and affinity under the characteristic acidic conditions of the tumor microenvironment (TME), while its binding is highly reduced under normal cells' alkaline physiological conditions (pH 7.4).

In vivo studies with BA3182 indicate that the therapeutic index was improved more than 100-fold relative to non-CAB variants, supporting the potential differentiation of CAB bispecific antibodies versus more traditional bispecific antibodies.