Tonix Pharmaceuticals Holding Corp. announced the completion of the clinical stage of its Phase 1, single ascending dose escalation trial of TNX-1500 (Fc-modified humanized anti-CD40L monoclonal antibody, or mAb)* in healthy volunteers. TNX-1500 is in development for the prevention of rejection in solid organ and bone marrow transplant and for the treatment of autoimmune disorders.

TNX-1500 (Fc-modified humanized anti-CD40L mAb) is a humanized monoclonal antibody that interacts with the CD40-ligand (CD40L), also known as CD154. TNX-1500 is being developed for the prevention of allograft and xenograft rejection, for the prevention of graft-versus-host disease (GvHD) after hematopoietic stem cell transplantation (HCT) and for the treatment of autoimmune diseases. The first-in-human Phase 1 trial of TNX-1500 was initiated in the third quarter of 2023.

The primary objective of the Phase 1 trial is to assess the safety, tolerability, pharmacokinetics, and pharmacodynamics of intravenous (i.v.) TNX-1500. Eligible participants enrolled in the Phase 1 trial were distributed across three dosing cohorts (3 mg/kg, 10 mg/kg, and 30 mg/kg, respectively) and evaluated regularly over a 120-day period after dosing. This first-in-human trial is intended to support dosing in a planned Phase 2 trial in kidney transplant recipients.

Two published articles in the American Journal of Transplantation demonstrate TNX-1500 prevents rejection, prolongs survival and preserves graft function as a single agent or in combination with other drugs in non-human primate renal and heart allografts. No anti-CD40L mAb has been approved in any jurisdiction. In addition to TNX-1500, frexalimab and tegoprubart, tn03 fusion protein dazodalibep is being developed by Amgen (formerly Horizon Therapeutics Public Limited Company) for the treatment of Sjögren's Syndrome.

Dapirolizumab pegol, an anti-CD40L pegylated Fab, is being developed by UCB for the treatment of systemic lupus erythematosus.