This is a phase 2 study of the Bruton's Tyrosine Kinase Inhibitor, PCI-32765 (ibrutinib), in combination with bendamustine and rituximab (BR) in subjects with previously treated aggressive B cell non Hodgkin lymphoma (aB-NHL) including any subtype of diffuse large B cell lymphoma (DLBCL) primary mediastinal B cell lymphoma (PMBCL), double and triple hit DLBCL, transformed indolent lymphoma, unclassifiable aggressive B cell lymphoma between DLBCL and Burkitt lymphoma. Patients with CNS involvement (primary or secondary) will be excluded. Ibrutinib (IMBRUVICA®; PCI-32765; JNJ-54179060) is a first-in-class, potent, orally-administered covalently-binding small molecule inhibitor of Bruton's tyrosine kinase currently FDA approved for the treatment of relapsed Mantle cell lymphoma (MCL), Chronic Lymphocytic Leukemia (CLL) and waldenstrom Macroglobulinemia (WM).It is under constant investigation for the treatment of other B-cell malignancies. The initial approval of ibrutinib was received on 13 November 2013 by the United States Food and Drug Administration for the treatment of adult patients with MCL who have received at least 1 prior therapy. Ibrutinib has not been approved for marketing for the treatment of aggressive B cell lymphoma although Phase I trial in this setting has already been published. In Israel ibrutinib is registered for the treatment of MCL and CLL.