A Randomized Controlled Study of the Efficacy and Safety of Lenalidomide in the Treatment of Active IgG4-related Disease

Inclusion criteria

• Patients aged between 18 and 75 years who meet the 2019 American College of Rheumatology/European League Against Rheumatism (ACR/EULAR) classification criteria for IgG4-RD；
• Patients with active disease: For patients with initial treatment or relapse after drug withdrawal, active disease is defined as having an IgG4-RD Response Index (RI) of at least 2 points in at least one organ at the time of screening; for those experiencing relapse while on treatment, active disease is defined as having an IgG4-RD RI of at least 3 points in at least one organ at the time of screening；
• Patients with the clinical subtype of proliferative IgG4-RD；
• Patients who have no plans for pregnancy within the next 18 months and who agree to use reliable contraceptive measures during the study period；

Exclusion criteria

• IgG4-RD patients with only fibrotic features;
• Absolute neutrophil count <1.5×10^9 /L or platelet count <100×10^9/L;
• Creatinine clearance less than 60 ml/ min;
• Liver function Child-Pugh grade B or above;
• Chronic active infection requiring systemic treatment;
• Diagnosed with malignant tumor in the past five years;
• Patients with a history of thrombosis;
• Using biological agents within six months;
• Known to be allergic to lenalidomide or thalidomide;
• Pregnant or lactating women;
• Patients with any other medical conditions or for specific reasons judged by the investigator to be ineligible to participate in the study.