the present disclosure provides a fusion protein comprising il - 1 receptor antagonist fused to a hybrid fc . particularly the present disclosure relates to a fusion protein comprising il - 1 receptor antagonist fused to a human immunoglobulin hybrid fc fragment . in one embodiment , the hybrid fc fragment comprises igd and igg4 . also provided is a pharmaceutical composition comprising the present fusion protein , which are useful for treating autoimmune disease including rheumatoid arthritis , inflammatory bowel disease , psoriasis and diabetes and the like . the present fusion protein with excellent efficacy and reduced side effects is qualified for clinical development as therapeutic antibodies to treat autoimmune disease .