A non-interventional, multicenter, multinational retrospective analysis using electronic case report forms completed by the investigators based on information from patient medical records

All patients who satisfy the inclusion criteria for this study in each participating institution will be included. Considering the number of participating centers in Korea, Latin America (Mexico, Colombia), and Europe (Switzerland, Israel), the expected number of patients is 50.

This research involves only the collection and analysis of existing data, documents, and records. The information will be recorded by the investigators on a CRF in a way that the subjects cannot be identified directly or through identifiers linked to the subjects. Thus, this study should be reviewed and approved by the Institutional Review Board of each participating institute, and exemption from additional written informed consent should be applied.

1. Age, sex, nationality, ethnicity
2. Ann Arbor stage, disease involved sites, number of extranodal involvement, serum LDH concentration, ECOG performance status, presence of B symptoms, regional lymph node involvement, International Prognostic Index, bone marrow invasion at the time of pralatrexate treatment
3. Dose and schedule of pralatrexate, start date, last treatment date, other treatment modalities

Inclusion Criteria:

- 1. Histologically confirmed peripheral T-cell lymphoma according to following inclusion criteria of subtypes according to the 2016 revision of the World Health Organization classification of lymphoid neoplasm

1. Adult T-cell leukemia/lymphoma
2. Angioimmunoblastic T-cell lymphoma
3. Anaplastic large cell lymphoma, ALK positive
4. Anaplastic large cell lymphoma, ALK negative
5. Peripheral T-cell lymphoma, NOS
6. Enteropathy-type intestinal lymphoma
7. Hepatosplenic T-cell lymphoma
8. Extranodal NK/T-cell lymphoma, nasal type
9. Subcutaneous panniculitis-like T-cell lymphoma
10. Transformed mycosis fungoides
11. Mycosis fungoides
12. Sézary syndrome
13. Primary cutaneous CD30+T-cell lymphoproliferative disorder (primary cutaneous anaplastic large cell lymphoma)
14. Primary cutaneous gamma-delta T-cell lymphoma 2. Age ≥ 18 years old 3. Patients treated with pralatrexate due to relapse or refractory disease after primary and/or salvage treatment. Relapse following an autologous stem cell transplant allowed.

4. Patients treated with pralatrexate 30mg/m2 once a week for 6 weeks as part of a 7-week cycle. However, modified dose and/or schedule allowed.

Exclusion Criteria:

• 1. Histologically confirmed peripheral T-cell lymphoma with following exclusion criteria of subtypes

  1. Aggressive NK-cell leukemia
  2. T-cell prolymphocytic leukemia
  3. T-cell large granular lymphocytic leukemia
  4. Primary cutaneous CD30+ T-cell lymphoproliferative disorders (lymphomatoid papulosis) 2. Patients with active/symptomatic central nervous system (CNS) involvement. 3. HIV-related lymphoma 4. Prior allogeneic stem cell transplant within 6 months. 5. Concurrent active or history of other malignancies. 6. Concurrent uncontrolled serious medical or psychiatric conditions

All patients who satisfy the inclusion criteria for this study in each participating institution will be included. Considering the number of participating centers in Korea, Latin America (Mexico, Colombia), and Europe (Switzerland, Israel), the expected number of patients is 50.