NO INDUCTION OF ANTIBODIES IN PATIENTS TREATED WITH THE RECOMBINANT PLASMINOGEN-ACTIVATOR RETEPLASE (BM-06.022)

Any new substance produced by recombinant DNA techniques for therapeut ic use must be tested for its immunogenic properties. The purpose of t his study was to investigate whether the administration of i.v. double bolus of reteplase in patients with acute myocardial infarction leads to formation of specific antibodies. During the clinical development of reteplase 2640 plasma samples were tested, post dose between day 10 and 1 year, within 5 controlled clinical studies performed in Europe and the USA. Antibody titres were measured using an internally develop ed enzyme-linked immunoabsorbent assay (ELISA). If the absorbance test exceeded a specific upper limit (cut-off value), a competitive inhibi tion test was conducted. All patients tested who received reteplase we re found to be negative for reteplase specific antibodies. The confirm ation of absence of antibodies is consistent with the low rate of alle rgic reactions in controlled clinical trials with reteplase. Retreatme nt with reteplase is also expected to be free of the immunologic risks known to occur after administration of streptokinase or streptokinase -like thrombolytics.