Inclusion Criteria

Inclusion criteria:

- A histologically confirmed diagnosis of PTCL

- Patients must have relapsed or refractory disease after at least one prior systemic
anticancer regimen. Systemic anticancer therapy is defined as chemotherapy or
immunotherapy administered systemically.

- Patients must have at least one site of disease measurable in two dimensions by
computed tomography (CT).

- Age ≥ 18 years.

- Adequate bone marrow, liver, and renal functions.

- Eastern Cooperative Oncology Group (ECOG) performance status 0-2.

- Negative pregnancy test for women of childbearing potential.

Exclusion criteria:

- Relapse within 100 days of autologous or allogeneic bone marrow transplant.

- Prior HDAC inhibitor therapy.

- Co-existing active infection or any medical condition likely to interfere with trial
procedures.

- Severe cardiovascular disease.

- Clinically significant central nervous system disorders with altered mental status or
psychiatric disorders precluding understanding of the informed consent process and/or
completion of the necessary studies.

- Active concurrent malignancy (except adequately treated non-melanoma skin cancer or
carcinoma in situ of the cervix).

- Symptomatic or untreated central nervous system (CNS) metastases.

- Pregnant or breast-feeding women.

- Known infection with HIV, hepatitis B or hepatitis C.