Tecelac as antithymocyte globulin in conditioning for childhood allogeneic stem cell transplantation

Antithymocyte globulin (ATG) preparations in allogeneic stem cell transplantation are used in various conditioning regimens both to prevent graft rejection and reduce the incidence and severity of graft-versus-host disease. Tecelac (RATG) is a highly purified ATG preparation with high specific activity. The high specific antibody content implies the need for lower doses, with reduced side-effects in comparison to other ATGs. Here, we report on the first 10 patients worldwide who received RATG as part of conditioning. Patients were heterogeneous with regard to diagnoses and graft characteristics. RATG was given in cases of matched unrelated donors, mismatched family donors, reduced conditioning, or high risk for graft failure. Mostly mild allergic reactions toward RATG were seen. All of the patients engrafted in due time. Two died within 2 months of transplant of pulmonary complications not related to RATG. Two developed GVHD grade I, no chronic GVHD was seen to date. Viremia occurred in two, with no viral disease developed. Of the eight patients surviving, one suffered relapse of acute leukemia, one shows impending graft failure. The others are well. Using RATG in conditioning is feasible.