This phase III trial studies the side effects of sintilimab to see how well it works when given together with ifosfamide, carboplatin, and etoposide in treating patients with classic Hodgkin lymphoma that does not respond to first-line standard chemotherapy.

randomized, double-blind, two arms , multicenter

Inclusion Criteria:

1. Signed informed consent
2. Histopathologically confirmed cHL
3. Failed first-line standard combination chemotherapy
4. One measurable lesion (Lugano 2014)
5. Eastern Cooperative Oncology Group (ECOG) of 0-1
6. Male or female aged ≥18 years
7. Patients must have adequate organ and bone marrow function

Exclusion Criteria:

1. Patients must not have known central nervous system (CNS) involvement
2. Patients must not have had prior exposure to any immune checkpoint inhibitors including anti-PD-L1 agents, anti-PD-L2 agents, or anti-CTLA-4 monoclonal antibodies
3. Patients may not simultaneously participate in another interventional clinical study
4. Patients may not receive any other investigational agents within 4 weeks of study registration
5. Patients may not receive any other form of immunosuppressive therapy within 4 weeks prior to the first dose of study drug
6. Patients may not receive live attenuated vaccines within 4 weeks prior to the first dose of study drug (or plan to receive live attenuated vaccines during the study period)
7. Patients with known immunodeficiency are ineligible
8. Patients with known active TB (Bacillus tuberculosis) are ineligible
9. Patients must not have had prior allogeneic stem cell transplantation or allogeneic organ transplantation
10. Patients must not be pregnant or breastfeeding