The emerging role of ibrutinib in the treatment of chronic lymphocytic leukemia.

Drugs that selectively inhibit Bruton's tyrosine kinase (BTK), such as the new orally administered agent ibrutinib, are currently under investigation for the treatment of several types of B-cell malignancies. In this article, the authors present results of a Phase Ib/II study of ibrutinib in 85 patients with relapsed or refractory chronic lymphocytic leukemia (CLL). The enthusiasm generated by this paper relies on the fact that ibrutinib given orally on a daily basis produces very high response rates that are durable with minimal side effects. Interestingly, the favorable therapeutic index of ibrutinib may facilitate its use in combination with other agents active in the treatment of CLL. In addition, the use of an effective oral agent like ibrutinib whose efficacy does not translate into a high burden of toxicity should be considered in choosing therapy in the elderly. A challenging issue with ibrutinib is the possibility of overcoming chemotherapy in the treatment of CLL.