PT101

PT101 is an engineered interleukin-2 (IL-2) mutein fused to a protein backbone, designed to selectively activate and expand regulatory T cells (Tregs) for the treatment of autoimmune diseases. By introducing specific mutations into IL-2, PT101 increases its affinity for the CD25 subunit while reducing affinity for CD122/CD132, making its activity highly selective for Tregs over conventional T cells and natural killer (NK) cells. This selectivity aims to restore immune tolerance in conditions where autoimmunity is driven by dysfunctional or insufficient Treg activity. In clinical studies, PT101 has demonstrated potent and selective expansion of Tregs without significant activation of pro-inflammatory immune cell types or induction of pro-inflammatory cytokines. The drug was initially developed by Pandion Therapeutics and later acquired by Merck & Co., Inc., with primary indications including ulcerative colitis and systemic lupus erythematosus[2][3][5][7].

Other names

modified interleukin-2IL-2 muteinIL2 muteinIL 2 muteinTreg-selective IL-2 mutein Fc fusion protein