title: Breaking good: the inexorable rise of BTK inhibitors in the treatment of chronic lymphocytic leukaemia.
abstract: Although expressed in several haematological lineages and involved in multiple different signalling pathways, Bruton tyrosine kinase (BTK) plays an indispensible role in B cells in signalling from the B cell receptor (BCR) for antigen. Many B cell malignancies remain dependent on constitutive BCR signalling, making BTK a functional therapeutic target. Several BTK inhibitors (BTKi) with different kinomes and modes of action are being assessed clinically. This review documents the efficacy and toxicity of BTKi in chronic lymphocytic leukaemia (CLL). Clinically, the furthest in development is ibrutinib (trade name, Imbruvica), an irreversible BTKi, which has shown spectacular preliminary efficacy, with rapid reductions in lymph nodes accompanied by peripheral blood lymphocytosis. The lymphocytosis resolves slowly and most patients do not enter a complete remission. Nevertheless, it is possible to maintain many CLL patients, even those with adverse cytogenetic features, on drug for many months with minimal toxicities, thus potentially transforming the therapeutic paradigms for CLL. The efficacy, lack of toxicity and oral administration of BTKi will ensure their adoption in a wide range of B cell malignancies. An outstanding challenge is to incorporate BTKi with other precision medicines in a mechanism-based manner in order to dispense with conventional chemotherapy.
authors.affiliation: Department of of Cancer Studies and Molecular Medicine, University of Leicester, Leicester, UK; The Ernest and Helen Scott Haematological Research Institute, University of Leicester.
authors.forename: Claire V
authors.initials: CV
authors.lastname: Hutchinson
authors.forename: Martin J S
authors.initials: MJ
authors.lastname: Dyer
mesh_terms: D000077329:Agammaglobulinaemia Tyrosine Kinase; D000970:Antineoplastic Agents / Q000627:therapeutic use*; D002986:Clinical Trials as Topic / Q000379:methods; D006801:Humans; D015451:Leukemia, Lymphocytic, Chronic, B-Cell / Q000188:drug therapy* / Q000201:enzymology; D058990:Molecular Targeted Therapy / Q000379:methods; D047428:Protein Kinase Inhibitors / Q000627:therapeutic use*; D011505:Protein-Tyrosine Kinases / Q000037:antagonists & inhibitors* / Q000502:physiology; D013329:Structure-Activity Relationship
chemical_list: D000970:Antineoplastic Agents; D047428:Protein Kinase Inhibitors; D011505:Protein-Tyrosine Kinases; D000077329:Agammaglobulinaemia Tyrosine Kinase; C000625949:BTK protein, human
keywords: B cell receptor signalling; Bruton tyrosine kinase; chronic lymphocytic leukaemia; ibrutinib