Chidamide Maintenance for MRD-Positive Double-Expressor DLBCL in First Complete Remission

Patients with double-expressor DLBCL remain at increased risk of relapse despite achieving complete response after induction therapy. ctDNA-based MRD assessment may identify a subgroup with persistent molecular disease who are at particularly high risk for recurrence. Chidamide is an oral selective histone deacetylase inhibitor with potential antitumor and immune-modulating activity in B-cell lymphomas. This prospective, multicenter, single-arm, open-label phase 2 study will enroll adult patients with newly diagnosed CD20-positive double-expressor DLBCL, defined by MYC expression \>=40% and BCL2 expression \>=50% by immunohistochemistry, who achieve complete response after initial induction therapy but remain ctDNA MRD-positive. Participants will receive chidamide 20 mg orally on Days 1, 4, 8, and 11 of each 21-day cycle. ctDNA MRD will be monitored every 12 weeks. Treatment will stop upon two consecutive MRD-negative assessments, disease progression, intolerable toxicity, withdrawal of consent, or completion of 2 years of maintenance. The study will evaluate ctDNA MRD negativity rate and 2-year progression-free survival as primary endpoints, with event-free survival, overall survival, and safety as secondary endpoints.