BR109

BR109 is a novel fully humanized T-cell-engaging bispecific antibody that targets both GPRC5D (G-protein-coupled receptor family C group 5 member D) and CD3. It specifically mediates T-cell cytotoxicity against GPRC5D-positive multiple myeloma cells by engaging T-cells to target malignant plasma cells. Preclinical data show potent, concentration-dependent antitumor activity, both in vitro and in xenograft mouse models, triggering T-cell activation and cytokine release with evident tumor regression. BR109 is not cross-reactive with BCMA and is intended for use in hematologic malignancies, primarily multiple myeloma, including relapsed/refractory disease, as GPRC5D is upregulated in myeloma patients who relapse after BCMA-targeted therapies. The primary route of administration being explored is subcutaneous, based on comparable efficacy and potentially improved convenience and safety compared to intravenous administration[1][3][5].