Inclusion Criteria:

- Japanese patients at least 20 years of age.

- Patients histologically diagnosed with peripheral T-cell lymphoma by pathological
diagnosis of biopsied lesion. In this study, peripheral T-cell lymphoma is defined as
the following mature T-cell/NK-cell neoplasms found in the 4th edition of the WHO
Classification.

- Recurrent/refractory patients with a treatment history of at least one regimen.

- Patients with an enlarged lymph node or extranodal mass lesion clearly measurable in
two perpendicular directions and greater than 1.5 cm in maximum diameter on computed
tomography performed.

- Patients expected to survive for at least 3 months.

- ECOG PS 0-1.

- Patients with adequate hemopoietic efficacy, liver and kidney function.

- Patients from whom written consent has been obtained prior to study initiation.

Exclusion Criteria:

- Patients who received a chemotherapy agent or a high dose of a systemic
adrenocorticosteroid within 21 days prior to initial administration of the study
drug.

- Patients who received radiation therapy, phototherapy, or electron beam therapy
within 21 days prior to initial administration of the study drug.

- Patients who received another study drug within 28 days prior to initial
administration of the study drug.

- Patients who received antibody therapy within 100 days prior to initial
administration of the study drug.

- Patients with a history of allogeneic hematopoietic stem cell transplantation. Or
patients with a history of autologous hematopoietic stem cell transplantation within
100 days prior to initial administration of the study drug.

- Patients with cerebral metastasis or central nervous system lesion or a past history.

- Patients with active multiple primary cancer. Or patients with a history of a
malignant neoplasm other than peripheral T-cell lymphoma within the past 5 years.

- Patients with severe cardiovascular disease.

- Patients with congenital long QT syndrome.

- Patients with QTcF >0.48 sec.

- Patients positive for HBs antigen, HCV antibody or HIV antibody on immunological
investigation. Or patients positive for either HBc antibody or HBs antibody, and
showing DNA more than sensitivity in HBV-DNA assay.

- Patients positive for CMV antigen on immunological investigation.

- Patients with infectious disease requiring treatment consisting of intravenous
administration of antibacterial agent, fungicide, or antiviral drug.

- Patients with interstitial pneumonia or pulmonary fibrosis, or patients judged to
have insufficient pulmonary function.