Golidocitinib Versus Placebo as Maintenance Therapy for Peripheral T-Cell Lymphoma

Inclusion Criteria: * Signed written informed consent prior to any study-specific procedures and willingness to comply with all study requirements. * Age ≥18 years at the time of informed consent. * Eastern Cooperative Oncology Group (ECOG) performance status 0-1 without deterioration within 2 weeks before screening. * Histologically confirmed PTCL according to the 2016 WHO classification, limited to the following subtypes: PTCL-not otherwise specified (excluding primary cutaneous PTCL), ALK-positive anaplastic large cell lymphoma (ALK-ALCL), angioimmunoblastic T-cell lymphoma (AITL), or T-follicular helper phenotype PTCL (FTCL or PTCL-TFH). * Achieved complete response (CR) or partial response (PR) after first-line systemic standard chemotherapy with CHOP, BV-CHP, or CHOP-like regimens, as assessed by Lugano 2014 criteria; patients must be ineligible for HSCT (age \>65 years) or eligible but decline HSCT (age ≤65 years). The interval between completion of first-line therapy and planned first dose in this study must be ≤3 months. * Adequate bone marrow and organ function, including: * Absolute neutrophil count (ANC) ≥1.5×10⁹/L (≥1.0×10⁹/L if bone marrow is involved by lymphoma), without use of colony-stimulating factors within 7 days before study entry. * Platelet count ≥100×10⁹/L (≥75×10⁹/L if bone marrow is involved by lymphoma), without transfusion or platelet growth factors within 7 days before study entry. * Hemoglobin ≥10 g/dL. * Total bilirubin ≤2× upper limit of normal (ULN). * ALT and AST ≤2.5×ULN. * Serum creatinine ≤1.5×ULN or creatinine clearance ≥50 mL/min (calculated or measured). * Left ventricular ejection fraction (LVEF) ≥50% on echocardiography. * Willingness and ability to comply with study procedures and follow-up. Exclusion Criteria: * Ann Arbor stage I disease at initial diagnosis. * Prior treatments that could interfere with study therapy, including but not limited to: * Investigational agents or antineoplastic drugs within 30 days before first study dose. * Cytotoxic chemotherapy within 21 days before first study dose. * Systemic corticosteroids at a prednisone-equivalent dose \>10 mg/day within 7 days before first study dose. * Major surgery (excluding vascular access procedures) or severe trauma within 4 weeks before first study dose, or planned surgery during study treatment. * Antineoplastic monoclonal antibodies (including brentuximab vedotin) within 4 weeks before first study dose; radiotherapy within 3 weeks; other toxin- or radioisotope-conjugated antibodies within 10 weeks. * Prior treatment with any JAK or STAT3 inhibitor. * Antitumor immunotherapy (e.g., immune checkpoint inhibitors including PD-1, PD-L1, CTLA-4 antibodies) within 28 days before first study dose. * Live attenuated or viral vector vaccines within 28 days before first study dose. * Current use of vitamin K antagonists, antiplatelet or anticoagulant drugs that cannot be discontinued ≥7 days before first study dose. * Concomitant medications that are strong CYP3A inducers or inhibitors, or BCRP/P-gp substrates with narrow therapeutic index that cannot be stopped ≥7 days before first study dose, as specified in the protocol appendix. * Active hepatitis C infection (positive anti-HCV antibody). * Hepatitis B virus (HBV) DNA ≥1000 IU/mL or other HBV status not meeting protocol-defined criteria for safe inclusion. * Known HIV infection with confirmed positive serology. * Any uncontrolled, clinically significant comorbidities or laboratory abnormalities that, in the investigator's judgment, would increase risk or interfere with study participation. * History of drug-induced interstitial lung disease or current evidence of clinically significant interstitial lung disease. * Pregnant or breastfeeding women; women of childbearing potential and men with fertile partners who are unwilling or unable to use effective contraception during treatment and for the protocol-specified period after the last dose.