W308051

W308051 is a bispecific T-cell engager (BiTE) developed by GSK under license from WuXi Biologics for the treatment of metastatic castration-resistant prostate cancer (mCRPC). The molecule is designed to simultaneously bind to prostate-specific membrane antigen (PSMA) on the surface of tumor cells and the CD3 epsilon subunit of the T-cell receptor complex on T lymphocytes. This dual binding facilitates the formation of an immunological synapse, leading to T-cell activation and the subsequent release of perforins and granzymes to induce apoptosis in PSMA-expressing malignant cells. W308051 features an optimized affinity profile, with high potency against PSMA (KD of 16 pM) and a calibrated affinity for CD3 (KD of 60 nM) intended to maximize anti-tumor efficacy while minimizing systemic cytokine release, thereby potentially offering a wider therapeutic window compared to first-generation PSMA-targeting T-cell engagers like AMG160.