Chidamide Maintenance to Prevent Relapse After Allogeneic Hematopoietic Stem Cell Transplantation in Acute T-Lymphoblastic Leukemia/Lymphoma

Study Design:This is a prospective, multicenter, open‐label, randomized, parallel‐group, superiorityclinical trial. A total of 132 patients with ETP‐phenotype T‐ALL/LBL who have achievedcomplete remission after allo‐HSCT will be enrolled.Intervention:Chidamide Group: Oral chidamide 10 mg twice weekly (BIW) starting at Day +30 to +100post‐transplant. Treatment cycles are 4 weeks each, for a total of 26 cycles(approximately 24 months). Dose may be escalated to 20 mg BIW in case of MRD positivity.Control Group: Standard follow‐up without maintenance therapy. Regular assessments areperformed per the same schedule as the treatment group.Study Assessments:Efficacy: Relapse‐free survival (RFS), cumulative incidence of relapse (CIR), overallsurvival (OS), non‐relapse mortality (NRM).Safety: Adverse events graded by NCI‐CTCAE v6.0, including hematologic toxicity,infections, and transplant‐related complications (TA‐TMA, VOD/SOS, etc.).GVHD: Acute GVHD graded per MAGIC criteria, chronic GVHD per NIH 2014/2020 criteria.Exploratory: Minimal/measurable residual disease (MRD) dynamics by multi‐parameter flowcytometry (MFC) or qPCR/NGS; immune reconstitution (T/B/NK/Treg subsets);cytokine/chemokine profiling; patient‐reported outcomes (EQ‐5D‐5L, FACT‐BMT); and healtheconomic evaluation.Follow‐up:Patients will be followed for at least 24 months after the last patient is enrolled. Thetotal study duration is expected to be approximately 4 years.Statistical Analysis:The primary analysis will be performed on the modified intention‐to‐treat (mITT)population. RFS will be estimated using the Kaplan‐Meier method and compared by log‐ranktest. A Cox proportional hazards model will be used to estimate hazard ratios (HR) with95% confidence intervals (CI). For competing risk events (e.g., NRM for CIR), theFine‐Gray subdistribution hazard model will be applied. Sensitivity analyses will beconducted to assess robustness.Sample Size:Based on Schoenfeld's formula for log‐rank test, assuming a 2‐year RFS of 55% in thecontrol group and 75% in the chidamide group (HR ≈ 0.48), with a two‐sided alpha of 0.05,power of 80%, and 1:1 allocation, approximately 59 events are required. Accounting for a5% dropout rate, the total sample size is 132 patients (66 per group).