This is a phase 3, open-label, randomized, multinational study to evaluate the anti-tumor efficacy of golidocitinib versus investigator's choice in adult patients with relapsed/refractory peripheral T-cell lymphoma (r/r PTCL). This study will treat patients with pathologically confirmed PTCL who have relapsed after or been refractory/intolerant to at least one prior systemic treatment regimen(s).

Inclusion Criteria:

• The participants should sign the ICF and be able to comply with the relevant requirements in the ICF and protocol
• Age ≥ 18 years
• ECOG 0-2 score, life expectancy ≥ 12 weeks
• Patients must have histologically confirmed peripheral T-cell lymphoma according to the World Health Organization classification of lymphoma. Eligible subtypes are restricted to: PTCL-not otherwise specified, NOS (PTCL, NOS), Angioimmunoblastic T-cell lymphoma (AITL), anaplastic large-cell lymphoma ALK-positive (ALCL ALK+), anaplastic large-cell lymphoma ALK-negative (ALCL ALK-), Follicular T-cell lymphoma, or PTCL with T-follicular helper (TFH) phenotype (FTCL or PTCL-TFH), Enteropathy-associated T-cell lymphoma (EATL), Monomorphic epitheliotropic intestinal T-cell lymphoma (MEITL), Natural killer/T-cell lymphoma (NK/TCL), Hepatosplenic T-cell lymphoma (HSTCL), Subcutaneous panniculitis-like T-cell lymphoma (SPTCL)
• Progressed on, were refractory to or intolerant to at least one line of prior standard systemic therapies assessed by investigator
• Adequate bone marrow reserve and organ system functions
• Willing to comply with contraceptive restrictions

Exclusion Criteria:

• Any of previous or current treatment prohibited by protocol
• Any unresolved > grade 2 drug-related adverse events
• Lymphoma involving central nervous system
• Any of severe cardiac or pulmonary abnormalities
• Disease condition requires immunosuppressants, biologics, or NSAIDs
• Active infection
• Malignancy disease within five years
• Poorly controlled gastrointestinal disorder or inadequate absorption of medication
• Severe or poorly controlled systemic diseases