A Comprehensive Clinical and Pharmacological Review of Anti-T-Lymphocyte Immunoglobulin (Rabbit), ATG-Fresenius S (Grafalon)

Executive Summary

This report provides a comprehensive clinical and pharmacological review of ATG-Fresenius S, an immunosuppressive agent identified by DrugBank Accession Number DB05320. Contrary to its classification in some databases as a small molecule, ATG-Fresenius S is a complex biologic therapeutic. It is a purified, concentrated preparation of polyclonal rabbit-derived immunoglobulin G (IgG) antibodies. Its primary clinical applications are as an induction agent for the prophylaxis and treatment of acute rejection in solid organ transplantation (SOT), particularly kidney transplantation; the prevention of Graft-versus-Host Disease (GVHD) in patients undergoing allogeneic hematopoietic stem cell transplantation (HSCT); and as an immunosuppressive therapy for acquired aplastic anemia (AA).

The principal mechanism of action of ATG-Fresenius S is the profound and rapid depletion of circulating T-lymphocytes, the key mediators of allogeneic immune responses. This is achieved through a multifaceted process involving complement-dependent cytotoxicity (CDC) and the induction of apoptosis. Beyond simple cell depletion, its polyclonal nature allows it to modulate a wide array of cell surface molecules, thereby impairing leukocyte adhesion and trafficking, and exerting effects on other immune cell populations, including B-lymphocytes and dendritic cells.