Ultra-low-dose Radiation Therapy Followed by Orelabrutinib as First-line Treatment for Stage Ⅰ-Ⅱ MALT Lymphoma

This is a prospective, multicenter Phase 2 clinical trial named the MALT-RO study, evaluating ultra-low-dose radiation therapy followed by orelabrutinib as first-line treatment for adults with Stage I-II MALT lymphoma. The study aims to determine the efficacy and safety profile of this sequential regimen. Eligible participants aged 18 years or older with histologically confirmed MALT lymphoma, measurable lesions, no prior systemic anti-lymphoma therapy, adequate organ function, and an ECOG performance status of 0-1 will receive 4Gy ultra-low-dose radiation (2Gy daily for 2 consecutive days) followed by oral orelabrutinib 150mg once daily for up to 6 cycles (28 days per cycle). Patients with partial response or stable disease after 6 cycles may continue orelabrutinib monotherapy for up to 12 cycles or until disease progression. All participants will undergo regular safety monitoring, tumor assessments, and long-term follow-up every 3 months to evaluate treatment durability. This treatment strategy is designed to improve efficacy and achieve more favorable outcomes compared with standard approaches for MALT lymphoma, while minimizing treatment-related toxicities such as long-term organ damage, xerostomia, cataracts, and other complications related to conventional standard-dose radiation, thereby offering a well-tolerated, convenient, targeted therapeutic option for patients with MALT lymphoma under strict ethical oversight in accordance with the Declaration of Helsinki and Chinese Good Clinical Practice guidelines.