Safety and efficacy of chidamide for maintenance therapy after allogeneic hematopoietic stem cell transplantation in patients with T-ALL/T-LBL

Post-transplant relapse remains a primary obstacle to long-term survival in patients with T-cell acute lymphoblastic leukemia/lymphoma (T-ALL/T-LBL), underscoring the need for effective maintenance therapies. Although chidamide, a selective histone deacetylase inhibitor, has shown activity in T-cell malignancies, its role as post-transplant maintenance has been scarcely studied. To evaluate the efficacy and safety of chidamide as maintenance therapy in T-ALL/T-LBL patients after allogeneic hematopoietic stem cell transplantation (allo-HSCT). We retrospectively analyzed 75 T-ALL/T-LBL patients who underwent allo-HSCT (December 2019-January 2024). Thirty-eight patients received chidamide-based maintenance, and 37 served as controls (no maintenance or non-chidamide regimens). The primary endpoints were overall survival (OS) and progression-free survival (PFS); safety endpoints included graft-versus-host disease (GVHD) incidence and treatment-related adverse events. Chidamide maintenance was associated with significantly improved OS and PFS compared with the non-chidamide group (OS: p = 0.001; PFS: p = 0.006). Multivariate Cox regression identified chidamide maintenance (OS: p = 0.003; PFS: p = 0.006) and complete remission status before transplantation (OS: p = 0.013; PFS: p = 0.012) as independent favorable prognostic factors. Chidamide did not increase acute GVHD; chronic GVHD was numerically higher (26.32% vs. 13.51%) but mostly mild to moderate and manageable. Adverse events were primarily hematologic toxicity (bone marrow suppression) and gastrointestinal, generally manageable and rarely required treatment discontinuation. Chidamide maintenance after allo-HSCT significantly improves survival outcomes in T-ALL/T-LBL patients with an acceptable safety profile, while pre-transplant remission status further refines prognosis. Prospective studies are warranted to confirm these findings and optimize maintenance strategies in this setting.