Ginisortamab is an investigational, fully human immunoglobulin G4 P (IgG4P) monoclonal antibody designed for the potential treatment of gastrointestinal (GI) tumors. It functions as a specific inhibitor of Gremlin-1 (GREM1), a secreted protein. By binding with high affinity to Gremlin-1, ginisortamab neutralizes its biological activity, preventing it from interacting with its target ligands. Gremlin-1 is a key antagonist of the bone morphogenetic protein (BMP) pathway, and its inhibition by ginisortamab aims to restore normal BMP signaling, which is crucial for cellular differentiation, tissue homeostasis, and suppressing epithelial-to-mesenchymal transition (EMT)—processes often dysregulated in cancer progression and metastasis, particularly in GI tumors.