Navigating the changing landscape of BTK-targeted therapies for B cell lymphomas and chronic lymphocytic leukaemia

Abstract

The B cell receptor (BCR) signalling pathway has an integral role in the pathogenesis of many B cell malignancies, including chronic lymphocytic leukaemia, mantle cell lymphoma, diffuse large B cell lymphoma and Waldenström macroglobulinaemia. Bruton tyrosine kinase (BTK) is a key node mediating signal transduction downstream of the BCR. The advent of BTK inhibitors has revolutionized the treatment landscape of B cell malignancies, with these agents often replacing highly intensive and toxic chemoimmunotherapy regimens as the standard of care. In this Review, we discuss the pivotal trials that have led to the approval of various covalent BTK inhibitors, the current treatment indications for these agents and mechanisms of resistance. In addition, we discuss novel BTK-targeted therapies, including covalent, as well as non-covalent, BTK inhibitors, BTK degraders and combination doublet and triplet regimens, to provide insights on the best current treatment paradigms in the frontline setting and at disease relapse. In several B cell malignancies, BTK is a crucial mediator of oncogenic signalling pathways and inhibitors of this kinase have substantially improved patient outcomes. This Review discusses the currently approved indications for covalent and non-covalent BTK inhibitors, as well as mechanisms of resistance, and novel BTK-targeted agents and treatment strategies that have the potential to further improve outcomes.