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 administrati on 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 d uring percutaneous coronary intervention. Safety was measured as the incide nce of hypersensitivity reactions, major bleeding, and thrombocytopenia. Ef ficacy was assessed as event-free clinical success. Human antichimeric anti body (HACA) responses were also characterized. There were no cases of hyper sensitivity (95% upper confidence bound, 0.3%), major bleeding, or death. C linical 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 develo ped profound thrombocytopenia (< 20 x 10(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 transfusio n. Before a first readministration, a positive HACA titer was present in 22 of 454 patients (4.8%); after a first readministration, an additional 82 o f 432 (19.0%) became HACA-positive. HACA did not neutralize the in vitro in hibition of platelet aggregation by abciximab or correlate with clinical ev ents. Conclusions-The results, including overall rates of thrombocytopenia, were consistent with randomized clinical trials of first abciximab treatment. Ho wever, there was a shift from mild to profound thrombocytopenia, and cases of delayed presentation and of recur-rent thrombocytopenia were seen. These findings suggest that indications and guidelines for first-time use apply to retreatment, particularly the systematic monitoring for thrombocytopenia .