ITK Degradation to Block T-cell Receptor Signaling and Overcome Therapeutic Resistance in T-Cell Lymphomas
IL-2-inducible T cell kinase (ITK) is essential for T cell receptor (TCR) signaling and plays an integral role in T-cell proliferation and differentiation. Unlike the ITK homolog BTK, no inhibitors of ITK are currently FDA approved. In addition, recent studies have identified mutations within BTK that confer resistance to both covalent and non- covalent inhibitors. Here, as an alternative strategy, we report the development of BSJ-05-037, a potent and selective heterobifunctional degrader of ITK. BSJ-05-037 displayed enhanced anti-proliferative effects relative to its parent inhibitor BMS- 509744, blocked the activation of NF-kB/GATA-3 signaling and increased the sensitivity of T cell lymphoma cells to cytotoxic chemotherapy both in vitro and in  vivo. In summary, targeted degradation of ITK is a novel approach to modulate TCR signal strength that could have broad application for the investigation and treatment of T cell-mediated diseases. Overall design: NSG mice were xenografted with H9 cells and treated with vehicle control or BSJ-05-037 (50 mg/kg I.P., Q.O.D) for for 14 days.