Advantages: Ibrutinib, the first BTK inhibitor, has been approved by FDA for the treatment of refractory and relapse (r/r) MCL. In spite of encouraging efficacy, clinically often referred adverse events such as diarrhea, bleeding and atrial fibrillation,respectively following ibrutinib treatment. It has been hypothesized that poor target selectivity (inhibitive effect on EGFR, TEC, BMX and others) may partially explain the occurrence of these adverse events. As such, there are focused efforts to develop new BTK inhibitor with high target selectivity aiming to improve the safety.