pci-32765 and Arrhythmias--Cardiac

Inhibition of Bruton's tyrosine kinase (BTK) has revolutionized the treatment landscape for patients with chronic lymphocytic leukemia (CLL). By targeting this critical kinase in proximal B-cell receptor signaling, BTK inhibitors (BTKis) impair cell proliferation, migration, and activation of NF-κB. Clinically, because indefinite inhibition is a mainstay of therapy, there is an extended period of exposure in which adverse effects can develop. Given the impressive efficacy and activity of BTKis in the treatment of patients with CLL, appropriate management of treatment-emergent adverse events (AEs) is of paramount importance. Here we review the BTKi landscape and present the available toxicity and safety data for each agent. The long-term toxicity profile of ibrutinib, a first-in-class inhibitor, is well characterized and includes a clinically significant incidence of cardiac arrhythmias, bleeding, infection, diarrhea, arthralgias, and hypertension. Acalabrutinib, the initial second-generation BTKi to earn approval from the US Food and Drug Administration, demonstrates improved kinase selectivity for BTK, with commonly observed adverse reactions including infection, headache, and diarrhea. Mediated by both on-target inhibition of BTK and variable off-target inhibition of other kinases including interleukin-2-inducible T-cell kinase (ITK), tyrosine-protein kinase (TEC), and endothelial growth factor receptor (EGFR), the toxicity profile of BTKis is closely linked to their pattern of kinase binding. Other emerging BTKis include second-generation agents with variable degrees of kinase selectivity and third-generation agents that exhibit reversible noncovalent binding to BTK. We also highlight critical considerations for the prevention and monitoring of AEs and offer practical management strategies for treatment-emergent toxicities.

Topics: Adenine; Agammaglobulinaemia Tyrosine Kinase; Aged; Animals; Arrhythmias, Cardiac; Arthralgia; Benzamides; Diarrhea; Hemorrhage; Humans; Hypertension; Infection Control; Infections; Male; Piperidines; Protein Kinase Inhibitors; Pyrazines

Background Ibrutinib and acalabrutinib are Bruton tyrosine kinase inhibitors used in the treatment of B-cell lymphoproliferative disorders. Ibrutinib is associated with new-onset atrial fibrillation. Cases of sinus bradycardia and sinus arrest have also been reported following ibrutinib treatment. Conversely, acalabrutinib is less arrhythmogenic. The basis for these different effects is unclear. Methods and Results The effects of ibrutinib and acalabrutinib on atrial electrophysiology were investigated in anesthetized mice using intracardiac electrophysiology, in isolated atrial preparations using high-resolution optical mapping, and in isolated atrial and sinoatrial node (SAN) myocytes using patch-clamping. Acute delivery of acalabrutinib did not affect atrial fibrillation susceptibility or other measures of atrial electrophysiology in mice in vivo. Optical mapping demonstrates that ibrutinib dose-dependently impaired atrial and SAN conduction and slowed beating rate. Acalabrutinib had no effect on atrial and SAN conduction or beating rate. In isolated atrial myocytes, ibrutinib reduced action potential upstroke velocity and Na

Topics: Action Potentials; Adenine; Animals; Arrhythmias, Cardiac; Atrial Fibrillation; Benzamides; Cardiac Electrophysiology; Mice; Myocytes, Cardiac; Piperidines; Pyrazines; Sinoatrial Node

Topics: Adenine; Adverse Drug Reaction Reporting Systems; Aged; Arrhythmias, Cardiac; Drug Monitoring; Female; Humans; Incidence; Lymphoproliferative Disorders; Male; Middle Aged; Piperidines; Pyrazoles; Pyrimidines; Treatment Outcome; United States; United States Food and Drug Administration

Topics: Adenine; Arrhythmias, Cardiac; Humans; Piperidines; Pyrazoles; Pyrimidines

Topics: Adenine; Arrhythmias, Cardiac; Death, Sudden, Cardiac; Humans; Leukemia, Lymphocytic, Chronic, B-Cell; Male; Middle Aged; Piperidines; Pyrazoles; Pyrimidines