IL2-IL2Rα fusion protein

IL2-IL2Rα fusion protein (also known as BLN-326 or BMS-986326) is a novel, long-acting recombinant fusion protein consisting of interleukin-2 (IL-2) and the extracellular domain of the IL-2 receptor alpha (IL-2Rα, CD25) joined by a non-cleavable linker. Originally developed by the University of Miami and licensed to Bristol Myers Squibb, the asset was subsequently in-licensed by Beeline Medicines in 2025. The fusion protein is designed to selectively expand regulatory T cells (Tregs) while minimizing the activation of effector T cells and natural killer (NK) cells. It achieves this by forming inactive head-to-tail dimers that slowly dissociate into active monomers, simulating low-dose IL-2 therapy. It is currently in Phase Ib clinical development for the treatment of autoimmune and inflammatory diseases, including systemic lupus erythematosus (SLE), cutaneous lupus erythematosus (CLE), and atopic dermatitis, with preclinical research also exploring its potential in type 1 diabetes and viral-induced arthritis.

Other names

IL-2/CD25IL-2/CD25 fusion proteinIL-2/IL-2Rα fusion proteinIL2-CD25IL-2-CD25IL 2-CD25IL2-CD25 fusion proteinIL-2-CD25 fusion proteinIL 2-CD25 fusion proteinIL2/CD25 fusion proteininterleukin-2/interleukin-2 receptor alpha fusion proteinmIL-2/CD25