Bruton's tyrosine kinase inhibitors in B‐cell non‐Hodgkin's lymphomas

The B‐cell receptor pathway (BCR) is aberrantly activated in select B‐cell malignancies. This knowledge has allowed for the development of inhibitors of different crucial steps of this pathway. Bruton's tyrosine kinase (BTK) is a key component of BCR signaling and functions as an important regulator of multiple cell functions including differentiation, proliferation, and survival in various B‐cell malignancies. Ibrutinib is a potent, selective BTK inhibitor that has shown significant activity in specific subtypes of B‐cell non‐Hodgkin's lymphomas (NHLs). Given the high response rates, tolerability, and acceptable toxicities, ibrutinib was recently approved by the US Food and Drug Administration (FDA) for the treatment of patients with relapsed mantle cell lymphoma and chronic lymphocytic leukemia. It is also currently being evaluated in combination with chemotherapy and as frontline therapy in B‐cell NHL. This review summarizes the preclinical and clinical development of ibrutinib in the treatment of B‐cell NHL.