Inclusion Criteria:

          1. Patients with newly diagnosed double hit in first complete remission, anytime during
             the first 3 months after chemoimmunotherapy followed by autologous stem cell
             transplantation if there was no evidence of progression.

          2. Double hit lymphoma is defined as B-cell lymphoma with genetic abnormalities involving
             A) and in addition, B) and/or C): A) C-MYC arrangement or amplification by FISH study.
             B) BCL2 rearrangement or amplification by FISH study. C) BCL6 rearrangement or
             amplification by FISH study.

          3. ANC >/= 1,000, platelets >/= 75,000.

          4. AST and/or ALT < 3 times the ULN.

          5. Creatinine clearance > 30 ml/min (Cockcroft-Gault formula using ideal body weight).

          6. Male or female age >/= 18 years.

          7. ECOG performance status </= 2.

          8. Willing and able to participate in all required evaluations and procedures in this
             study protocol including swallowing capsules without difficulty.

          9. Ability to understand the purpose and risks of the study and provide signed and dated
             informed consent and authorization to use protected health information.

         10. Patient should preferably have received a pre-transplant conditioning with rituximab
             and Carmustine/Etoposide/Cytarabine/Melphalan/Rituxan (BEAM/R) . Other regimens which
             are similar may be accepted at the discretion of the PI.

        Exclusion Criteria:

          1. Prior chemotherapy within 3 weeks, nitrosoureas (carmustine) within 6 weeks,
             therapeutic anticancer antibodies within 4 weeks, radio- or toxin-immunoconjugates
             within 10 weeks, radiation therapy within 3 weeks, or major surgery within 2 weeks of
             first dose of study drug.

          2. Relapsed within three months post transplant.

          3. History of other malignancies within the past year except for treated basal cell or
             squamous cell skin cancer or in situ cervical cancer.

          4. Known CNS lymphoma.

          5. Clinically significant cardiovascular disease such as uncontrolled or symptomatic
             arrhythmias, congestive heart failure, or myocardial infarction within 6 months of
             screening, or any Class 3 (moderate) or 4 (severe) cardiac disease as defined by the
             New York Heart Association Functional Classification.

          6. Requires treatment with a strong cytochrome P450 (CYP)3A inhibitor (i.e. Voriconazole,
             posaconazole, itraconazole, clarithromycin, etc.) or inducer (carbamazepine, rifampin,
             phenytoin, etc.).

          7. AST and/or ALT >/= 3 times the ULN.

          8. Malabsorption syndrome, disease significantly affecting gastrointestinal function, or
             resection of the stomach or small bowel or symptomatic ulcerative colitis, symptomatic
             inflammatory bowel disease, or partial or complete bowel obstruction.

          9. Known history of human immunodeficiency virus or active infection with hepatitis C
             virus or hepatitis B virus or any uncontrolled active systemic infection.

         10. Positive pregnancy test in women of childbearing potential.

         11. Lactating or pregnant or will not agree to use contraception during the study and for
             30 days after the last dose of study drug if sexually active and able to bear
             children.

         12. Concomitant use of warfarin or other Vitamin K antagonists.