Tonix Pharmaceuticals Holding Corp. announced favorable Phase 1 safety and biomarker data for TNX-1500, its third-generation Fc-modified anti-CD40L monoclonal antibody being developed for organ transplant rejection prevention. The data was presented at the 61st Annual Congress of the Japan Society for Transplantation in Nagoya, Japan, by CEO Seth Lederman, M.D.
"We are encouraged by the favorable safety and biomarker data from the Phase 1 study, which support the continued development of TNX-1500 as a novel immunomodulatory approach in transplantation and autoimmune diseases," said Dr. Lederman.
Novel Mechanism Targets CD40L Pathway
TNX-1500 is a humanized monoclonal antibody that binds and functionally inhibits CD40-ligand (CD40L), also known as CD154. The dimeric antibody was specifically designed to target cell-associated CD40L, which plays important roles in organ rejection. The molecule's engineering focused on minimizing thromboembolic risk while maintaining immunomodulatory activity.
Dr. Lederman noted the connection between anti-CD40L treatment and T-regulatory cells, stating, "Several studies have shown that anti-CD40L treatment of animals with transplanted organs is associated with an increase in the number and activity of T-regulatory cells." He highlighted the recent Nobel Prize in Physiology or Medicine 2025 awarded to Mary Brunkow, Fred Ramsdell and Shimon Sakaguchi for their discovery and characterization of T-regulatory cells and their role in peripheral immune tolerance.
Preclinical Efficacy Demonstrated
Two published articles in the American Journal of Transplantation demonstrate TNX-1500's efficacy in preventing rejection, prolonging survival and preserving graft function as a single agent or in combination with other drugs in non-human primate renal and heart allografts.
The presentation was part of a breakfast seminar that included collaborations with Harvard researchers. Professor Richard Pierson III from Massachusetts General Hospital presented on "CD154/CD40 blockade with Fc-modified anti-CD154 mAb for heart transplantation," while Professor Tatsuo Kawai discussed "CD154/CD40 blockade with Fc-modified anti-CD154 for kidney transplantation."
Development Pipeline and Applications
TNX-1500 is being developed for multiple indications including prevention of allograft and xenograft rejection, prevention of graft-versus-host disease after hematopoietic stem cell transplantation, and treatment of autoimmune diseases. The company outlined next steps toward Phase 2 development for kidney transplant rejection prevention and autoimmune indications.
Tonix Pharmaceuticals operates as a fully-integrated biotechnology company with marketed products including Tonmya, the first FDA-approved prescription medicine for fibromyalgia in more than 15 years. The company's development portfolio spans central nervous system disorders, immunology, immuno-oncology, rare disease and infectious disease applications.
TNX-1500 remains an investigational biologic and has not been approved for any indication.
