MCL is a distinct subtype of non-Hodgkin’s lymphoma, accounting for nearly 10% of all patients with lymphoma. The typical patient is characterized as Caucasian (2:1), male (2.5:1), and with a median age of 68 years, and patients usually present with disseminated morbidity, including extensive lymph node enlargement and bone marrow involvement. mcl is incurable, relapse is very common, and most patients die from disease progression (PD). In addition, commonly used chemotherapy regimens lead to bone marrow suppression, making treatment of elderly patients particularly challenging. Therefore, there is an urgent need for a new drug with good efficacy and low toxicity. Ibrutinib is a novel, once-daily, oral covalent inhibitor of BTK approved by the US FDA and European Medicines Agency for the treatment of non-primary lymphoblastic patients. It is also approved for the treatment of patients with non-primary chronic lymphocytic leukemia (CLL) and CLL with 17p deletion. Recently, Ibrutinib was also approved by the FDA for the treatment of patients with Walden’s macroglobulinemia. The approval of Ibrutinib for the treatment of patients with relapsed refractory MCL was directly accelerated by a previous international multicenter unblinded Phase 2 clinical study that demonstrated an overall response rate (ORR) of up to 68% (21% CR) and achieved a median duration of sustained response (DOR) of 17.5 months at a median follow-up of 15.3 months. Furthermore, ibrutinib had a good safety profile compared to the current standard of care and was rarely discontinued due to the occurrence of adverse events (AEs). A follow-up report to this study was recently published in Blood with results from the long-term follow-up. The results related to the safety and efficacy of the ibrutinib clinical study (median follow-up 26.7 months) were updated. The study included 111 patients taking 560 mg of ibrutinib orally daily, and those with stable disease or better outcomes entered the extended long-term clinical study. The primary study endpoint was ORR. median age of patients was 68 years (40-84 years), and these patients had received a median of 3 prior treatments (1-5). median duration of treatment with ibrutinib was 8.3 months, 46% of patients were treated for more than 12 months, and 22% of patients were treated for more than 2 years. ORR was 67% (23% CR), and median duration of treatment response was 17.5 months. PFS and OS at 24 months were 31% and 47%, respectively. Common AEs with an incidence of more than 30% included diarrhea (54%), malaise (50%), regurgitation (33%), and dyspnea (32%). The most frequent grade 3 or higher infections included pneumonia (8%), urinary tract infection (4%) and cellulitis (3%). Common grade 3 or higher hemorrhagic events with an incidence of more than 2% included hematuria (2%) and subdural hematoma (2%). Common hematologic side effects of all diseases included thrombocytopenia (22%), neutropenia (19%), and anemia (18%). The incidence of infection, diarrhea and bleeding was highest in the first six months and decreased thereafter. In patients with refractory/relapsed MCL, ibrutinib continues to maintain sustained efficacy and a good safety profile with long-term follow-up.