KRP-M223

KRP-M223 is a small molecule drug developed as an antagonist of the Mas-related G protein-coupled receptor X2 (MRGPRX2), a receptor predominantly expressed on mast cells. MRGPRX2 is implicated in mast cell-mediated allergic and inflammatory responses, distinct from IgE receptor-driven pathways. By inhibiting MRGPRX2, KRP-M223 aims to prevent mast cell activation and degranulation, blocking the release of mediators such as histamine that drive chronic spontaneous urticaria (CSU) and other mast cell–related disorders. Designed for allergic and inflammatory diseases with a primary focus on CSU, KRP-M223 is being advanced under global development by Novartis, with original discovery and in-licensing rights retained by Kyorin Pharmaceutical.