To investigate the tolerability and safety of OPB-111077 in combination with bendamustine and rituximab in patients with r/r DLBCL.

Inclusion Criteria:

• Patients with a definite diagnosis of Diffuse large B-cell lymphoma(DLBCL)
• Patients who have received at least initial standard treatment
• Patients with measurable lesions (based on International Working Group [IWG] 2014 criteria)
• Patients with an Eastern Cooperative Oncology Group (ECOG) performance status (PS) score of 0 or 1

<Only for dose-expansion stage>

• Patients who are pathologically diagnosed as CD20 positive lymphoma
• Patients who have a history of being treated with 1 to 5 regimens of previous chemotherapy for the underlying disease

Exclusion Criteria:

• Patients who are candidates for autologous or allogeneic hematopoietic stem cell transplantation
• Patients who were refractory to initial standard treatment
• Patients who have a history of bendamustine administration and are intolerant to bendamustine
• Patients with central nervous system (CNS) involvement of lymphoma or with a history of CNS involvement of lymphoma
• Patients diagnosed with DLBCL transformed from low-grade B-cell non-Hodgkin's lymphoma (NHL)

<Only for dose-expansion stage>

- Patients who have a history of rituximab administration and are intolerant to rituximab

The focus of this study is a rare disease.