Please assess the completion status of the following clinical trial:

Trial Title: Study of TQB2450 Injection in Subjects With Relapsed or Refractory Primary Mediastinal Large B-cell Lymphoma

Study Design Characteristics:
- Allocation: None
- Intervention Model: SINGLE_GROUP
- Observational Model: None
- Primary Purpose: TREATMENT
- Time Perspective: None
- Masking: NONE
- Phase: PHASE2
- Number of Arms: 1.0

Eligibility Criteria:
Inclusion Criteria:~* 1. Histologically confirmed relapsed or refractory primary mediastinal large B-cell lymphoma.~  2. 18 and 75 years; Eastern Cooperative Oncology Group (ECOG) performance status score of 0 or 1; Life expectancy \> 3 months.~  3. At least one measurable lesion. 4. Left ventricular ejection fraction (LVEF) measured by the cardiac echocardiography ≥ 50%.~  5. Screening laboratory values must meet the following criteria:hemoglobin ≥ 80 g/L; neutrophils ≥ 1.5\*10\^9/L; platelets ≥ 100 x 10\^9/ L.~  6. Understood and signed an informed consent form.~Exclusion Criteria:~* 1. Hypersensitivity to recombinant humanized anti-PD-1 monoclonal Abm or its components.~  2. Prior therapy with an anti-programmed cell death (PD)-1, anti-PD-L1, anti-PD-L2, or anti-cytotoxic T-lymphocyte-associated antigen-4 (CTLA-4) antibody ,or any other antibody or drug specifically targeting T-cell co-stimulation or checkpoint pathways.~  3. Has received chemotherapy, surgery, radiotherapy, the last treatment from the first dose less than 4 weeks, or oral targeted drugs for less than 5 half-lives, or oral fluorouracil pyridine drugs for less than 14 days, mitomycin C and nitrosourea for less than 6 weeks.~  4. Has received emergency cytoreductive surgery to control tumors. 5. Has received allogeneic hematopoietic stem cell transplantation within the last 5 years.~  6. Has adverse events caused by previous therapy except alopecia that did not recover to ≤grade 1.~  7. Has diagnosed and/or treated additional malignancy within 5 years prior to randomization. Exceptions include basal cell skin cancer, squamous cell carcinoma of skin, melanoma skin and cancer carcinoma in situ of the cervix.~  8. Has definite central nervous system (CNS) infiltration of lymphoma, including brain parenchyma, meningeal invasion or spinal cord compression.~  9. Has any active autoimmune disease or a history of autoimmune disease. 10. Has serious or uncontrolled diseases such as history of chronic heart failure.~  11. Has any active autoimmune disease or a history of autoimmune disease. 12. Has received blood transfusion, erythropoietin granulocyte colony stimulating factor(G -CSF)，or Granulocyte macrophage colony stimulating factor(GM-CSF) within 4 weeks before the first dose.~  13. Has vaccinated with vaccines or attenuated vaccines within 4 weeks before the first dose.~  14. Has received surgery, or unhealed wounds within 4 weeks before the first dose.~  15. Has Hepatic, renal, blood coagulation dysfunction. 16. Has interstitial lung disease or non-infectious pneumonia and present residual lesions.~  17. Has received systemic treatment for active infection before the first dose.~  18. Has active or latent tuberculosis. 19. Hepatitis B virus surface antigen (HBsAg) positive, and hepatitis B virus DNA copy number \> upper limit of normal.~  20. Human immunodeficiency virus antibody positive , hepatitis C antibody (HCV-Ab) and hepatitis C virus DNA copy number \> upper limit of normal.~  21. Breastfeeding or pregnant women. 22. According to the judgement of the researchers, there are other factors that subjects are not suitable for the study.

- Gender: ALL
- Minimum Age: 18 Years
- Maximum Age: 75 Years
- Healthy Volunteers: f

Study Arms:
- TQB2450 (Type: EXPERIMENTAL): TQB2450 1200 milligrams (mg) administered intravenously (IV) on Day 1 of each 21-day cycle.

Based on this trial design, predict the completion outcome and termination type (if applicable).