Abciximab readministration: results of the ReoPro Readministration Registry.

BACKGROUND: Platelet glycoprotein IIb/IIIa blockade with abciximab (ReoPro) improves the clinical outcomes of percutaneous coronary intervention. This registry was conducted to characterize the effects of repeated administration of abciximab during intervention. METHODS AND RESULTS: We recruited 500 consecutive patients at 22 centers in the United States who were receiving abciximab for at least a second time during percutaneous coronary intervention. Safety was measured as the incidence of hypersensitivity reactions, major bleeding, and thrombocytopenia. Efficacy was assessed as event-free clinical success. Human antichimeric antibody (HACA) responses were also characterized. There were no cases of hypersensitivity (95% upper confidence bound, 0.3%), major bleeding, or death. Clinical success was 94.4%. Thrombocytopenia occurred in 23 patients (4.6%; 95% CI, 2.8% to 6.4%), including 12 (2.4%; 95% CI, 1.1% to 3.7%) who developed profound thrombocytopenia (<20x10(9) cells/L). In 2 patients (0.4%), profound thrombocytopenia did not develop until after hospital discharge; in 4 (0.8%), profound thrombocytopenia recurred despite platelet transfusion. Before a first readministration, a positive HACA titer was present in 22 of 454 patients (4.8%); after a first readministration, an additional 82 of 432 (19.0%) became HACA-positive. HACA did not neutralize the in vitro inhibition of platelet aggregation by abciximab or correlate with clinical events. CONCLUSIONS: The results, including overall rates of thrombocytopenia, were consistent with randomized clinical trials of first abciximab treatment. However, there was a shift from mild to profound thrombocytopenia, and cases of delayed presentation and of recurrent thrombocytopenia were seen. These findings suggest that indications and guidelines for first-time use apply to retreatment, particularly the systematic monitoring for thrombocytopenia.

Readministration of abciximab: interim report of the ReoPro readministration registry.

Even with continued improvements in the technology of percutaneous coronary intervention (PCI), approximately 10% to 20% of patients undergoing PCI will require repeat procedures within 1 year. Furthermore, because of the chronic nature of coronary artery disease, many patients will require additional treatment with PCI well after an initial episode of care. Abciximab (ReoPro), a chimeric (murine/human) monoclonal antibody fragment (c7E3 Fab), has been shown to significantly improve periprocedural and long-term outcomes associated with PCI and to reduce the need for repeat target vessel revascularization. However, because the structure of abciximab is derived from an antibody, concern has been raised about subsequent repeat administration. To prospectively evaluate the safety and efficacy of abciximab readministration, we established the ReoPro Readministration Registry with the intent to determine the efficacy, human antichimeric antibody response and rates of thrombocytopenia, bleeding, intracranial hemorrhage, and anaphylaxis in at least 500 patients being retreated with abciximab. The study was conducted at 19 centers beginning in March 1997. This article details interim data that are based on the first 329 patients. Data to date indicate that readministration with abciximab is safe and efficacious and that the same indications for first-time use should apply to subsequent readministration.