BTK and mantle cell lymphoma: Acalabrutinib (ACP-196) is a BTK inhibitor that has been proven to have a more enhanced efficacy than ibrutinib in canine studies.204 A phase 2 study (NCT02213926) reported an ORR of 81% (CR 40%) in relapsed or refractory MCL.205 The FDA has approved acalabrutinib for treating relapsed or refractory MCL.