Application of Orelabrutinib With or Without CD20 Monoclonal Antibody in Previously Untreated Marginal Zone Lymphoma

This study focuses on treatment-naïve marginal zone lymphoma (MZL) patients and aims to investigate the efficacy and safety of orelabrutinib combined with or without CD20 monoclonal antibody. Given the current lack of a standard first-line treatment regimen for MZL, and the limited efficacy and significant side effects associated with commonly used immunochemotherapy regimens, chemotherapy-free approaches have attracted considerable attention. As a domestically developed new-generation BTK inhibitor, orelabrutinib exhibits high selectivity and a favorable safety profile, and demonstrates synergistic effects with CD20 monoclonal antibodies. The study enrolls treatment-naïve MZL patients at different stages, administering either orelabrutinib monotherapy or combination therapy with a CD20 monoclonal antibody. Efficacy indicators, such as overall response rate and complete response rate, are closely monitored, with tumor changes assessed through regular imaging and laboratory examinations. Meanwhile, all types of adverse reactions are documented in detail to evaluate safety. Long-term follow-up is conducted to track progression-free survival and overall survival, comprehensively analyzing whether this combination regimen can emerge as a highly effective, low-toxicity, chemotherapy-free option. This is a single-arm study without a control group. All subjects will receive orelabrutinib treatment but will be stratified based on disease stage and clinical characteristics into the following two groups: 1. Stage I MZL Patient Group (Monotherapy Group) Treatment regimen: Orelabrutinib monotherapy. Dosage and administration: Orelabrutinib 150mg, once daily (qd), taken continuously for 21 days per treatment cycle (d1-d21), for a total of 6 cycles (C1-C6). Target population: Patients with Ann Arbor Stage I gastric MALT MZL, including H. pylori-negative patients or those with unsatisfactory response after anti-H. pylori therapy, as well as other Stage I MZL patients unsuitable for local radiotherapy. Sample size: 50 cases. 2. Stage II-IV MZL Patient Group (Combination Therapy Group) Treatment regimen: Orelabrutinib combined with a CD20 monoclonal antibody. Dosage and administration: Orelabrutinib 150mg, once daily (qd), taken continuously for 21 days per treatment cycle (d1-d21), for a total of 6 cycles (C1-C6). CD20 monoclonal antibody (either Rituximab 375mg/m², intravenous infusion, Day 1 of each cycle, C1-C6; or Obinutuzumab 1000mg, intravenous infusion, on Days 1, 8, and 15 of Cycle 1 \[C1\], and on Day 1 of Cycles 2-6 \[C2-C6\]). Target population: Patients with Ann Arbor Stage II-IV non-gastric MALT MZL, nodal MZL, splenic marginal zone lymphoma (SMZL), and other Stage II-IV MZL patients unsuitable for local radiotherapy. Sample size: 38 cases.