Treatment of steroid-refractory acute graft-versus-host disease with anti-CD147 monoclonal antibody ABX-CBL

ABX-CBL, an immunoglobulin M murine monoclonal antibody, recognizes CD147 a nd initiates cell killing through complement-mediated lysis. In a dose-find ing trial, 27 patients with steroid-refractory acute graft-versus-host dise ase (GVHD) received ABX-CBL at 0.01 (presumed no effect dose), 0.1, 0.2, or 0.3 mg/kg per day, and an additional 32 patients were given ABX-CBL at 0.2 or 0.15 mg/kg per day. All patients had undergone allogeneic transplantati on for malignant or nonmalignant disorders and received GVHD prophylaxis, g enerally with methotrexate- and cyclosporine-containing regimens. None resp onded to methylprednisolone, given for a minimum of 3 days. ABX-CBL was sta rted 20 to 236 (median, 47) days after transplantation; it was given for 7 consecutive days and was followed by 2 infusions per week for 2 more weeks. Among 51 patients evaluable for efficacy, 26 (51%) responded, including 13 with complete responses (CR) and 13 with partial responses (PR). CR lastin g 14 days or longer or PR lasting 7 days or longer occurred in 21 (41%; 8 C R, 13 PR) patients, including 19 of 43 (44%) patients who received 0.1 to 0 .3 mg/kg ABX-CBL and 2 of 8 (25%) patients given 0.01 mg/kg per day. Myalgi as at doses 0.2 mg/kg or greater were dose limiting and resolved without se quelae. Causes of death included organ failure, progressive GVHD, and infec tion. No death was attributed to ABX-CBL. At 6 months after the initiation of ABX-CBL therapy, 26 (44%) patients were surviving. These results are enc ouraging. Further studies on the use of ABX-CBL in the management of GVHD a re warranted. (C) 2001 by The American Society of Hematology.