Inclusion Criteria:

- Confirmed diagnosis of PTCL expressing CD30 receptor. Diagnosis will be based on
identification of PTCL in biopsy specimens characterized by positivity for CD30
staining in the malignant cell population. Following PTCL subtypes will be eligible:
Peripheral T - cell lymphoma, not otherwise specified (NOS); Angioimmunoblastic
T-cell Lymphoma; Subcutaneous Panniculitis Like T-cell Lymphoma; Hepatosplenic
gamma/delta T cell Lymphoma; Extranodal natural killer (NK)T-cell Lymphoma, nasal
type; Enteropathy-associated T-cell lymphoma; Adult T-cell Leukemia/lymphoma; T-cell
prolymphocytic leukemia; Primary cutaneous gamma-delta T-cell lymphoma; Aggressive NK
cell leukemia; Epstein Barr Virus(EBV)-positive T-cell lymphoproliferative disorders
of childhood; Transformed mycosis fungoides who have progressed following treatment
with both methotrexate and bexarotene; Sezary syndrome

- Histology slides and pathology material must be available at the site for each
patient before enrollment in order to be sent to the Leading Institution of the study
for central pathology review and pharmacodynamic studies.

- Patients must have progressive, relapsed or refractory disease after: At least one
prior systemic anti-lymphoma regimen (chemotherapy or immunotherapy except for
transformed mycosis fungoides as described previously); Relapsed or failed autologous
or allogeneic stem cell transplant.

- Understand and voluntarily sign an Institutional Review Board (IRB) approved informed
consent form

- Must have at least one site of disease (index lesion) measurable in two dimensions by
computed tomography (CT)

- Patients with leukemic form of PTCL who will not have a measurable lesion in two
dimensions by CT scan, relapsed or refractory disease must be detected by
immunohistochemistry or flow cytometry and molecular clonality studies in bone marrow
or peripheral blood.

- At least 4 weeks since the last chemotherapy, radiation therapy, immunotherapy or any
investigational non-immunotherapy products

- Must meet the following criteria within 4 days before the first dose of study drug:

- Neutrophils ≥1,000/ul

- Hemoglobin ≥ 8 g/dL

- Platelets≥ 50.0x10^9 /L

- Total bilirubin ≤ 1.5 x upper normal limit, or ≤ 5 x upper normal limit if
documented hepatic involvement with lymphoma or history of Gilbert's Syndrome

- Aspartate aminotransferase (AST) and alanine aminotransferase (ALT) ≤ 3 x upper
normal limit (≤ 5 x upper normal limit if documented hepatic involvement with
lymphoma)

- Calculated creatinine clearance ≥ 40 mL/min/1.73 m^2 based on Cockcroft and
Gault method

- PT or International Normalization Ratio (INR), and Activated Partial
Thromboplastin Time (APTT) ≤ 1.5 x upper limit of normal unless patient is
receiving anticoagulants. If patient is on anticoagulation therapy, levels
should be within therapeutic range.

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

- Negative pregnancy test for women of childbearing potential

- Recovered (≤ Grade 1 toxicity) from the reversible effects of prior
antineoplastic therapy

Exclusion Criteria:

- Any of the following cardiovascular conditions or values within 6 months before the
first dose of study drug: Myocardial infarction and the New York Heart Association
(NYHA) Class III or IV heart failure

- History of another primary malignancy not in remission for at least 3 years; except
adequately treated patients with completely resected in situ carcinoma, such as
nonmelanoma skin cancer and cervical carcinoma in situ on biopsy or a squamous
intraepithelial lesion on Pap smear, or localized prostate cancer with
prostate-specific antigen (PSA) <1 ng/ml

- Known active cerebral/meningeal involvement with lymphoma. Asymptomatic patients with
previously treated and resolved central nervous system (CNS) lymphoma involvement are
permitted.

- Prior administration of Brentuximab vedotin

- Corticosteroid monotherapy for lymphoma within 2 weeks of the first dose of study
drug

- Any serious underlying medical condition that, in the opinion of the investigator or
medical monitor, would impair the ability to receive or tolerate the planned
treatment

- Known hypersensitivity to recombinant proteins, or any component contained in the
drug formulation

- Female patients who are lactating or have a positive serum pregnancy test during the
screening period