How I manage ibrutinib-refractory chronic lymphocytic leukemia.

The introduction of the Bruton tyrosine kinase (BTK) inhibitor ibrutinib has dramatically changed the management of chronic lymphocytic leukemia (CLL). Although responses have been durable in the majority of patients, relapses do occur, especially in the high-risk patient population. Most relapses occur as the result of acquired mutations in BTK and PLCG2, which may facilitate success with alternative targeted therapies. As outcomes after ibrutinib relapse have been reported to be poor, specific strategies are needed for this patient population. Here, I discuss the diagnosis and management of ibrutinib-refractory CLL. The focus will be on common clinical scenarios that can be mistaken for relapse and how to accurately determine which patients are relapsing. Because there is no established standard of care, I discuss currently available options for standard therapy and existing clinical data. I also discuss new agents with the potential to be effective in patients refractory to ibrutinib. Finally, I discuss strategies for long-term disease control in this patient population.