1. Rationale In mantle cell lymphoma, the conventional chemotherapy achieves only temporary responses with a median duration of remissions only from 1 to 2 years. Therefore, mantle cell lymphoma is known as one of the B-cell lymphomas with poor prognosis. Although the treatment outcome of mantle cell lymphoma has been improved since intensive chemotherapy regimens such as HyperCVAD was used, a substantial number of patients are still frequently relapsed after chemotherapy. After relapse, most of them became refractory to various kinds of salvage treatment. That is why the results of most salvage chemotherapy regimens were disappointing. In addition, mantle cell lymphoma generally occurs in elderly people. Thus, intensive salvage chemotherapy may not be feasible for elderly patients. Therefore, an effective, novel combination treatment is urgently needed in relapsed or refractory mantle cell lymphoma patients.