Final results of the ReoPro readministration registry.

Because of its potential for antigenicity, theoretical concerns related to readministration of abciximab have been raised. We conducted the ReoPro Readministration Registry to assess the efficacy and safety of abciximab readministration. A total of 1,342 patients who underwent percutaneous coronary intervention and who received abciximab for at least a second time were recruited. Safety end points were hypersensitivity reactions, major bleeding, and thrombocytopenia (TCP). Human antichimeric antibody (HACA) titers were determined before and after readministration. Procedural success was 98% and was not influenced by the number of courses of abciximab or the presence of HACA. There were no cases of anaphylaxis. There were 5 minor allergic reactions, none of which required termination of the infusion. Clinically significant bleeding occurred in 31 patients (2.3%), including 1 (0.07%) with intracranial hemorrhage. TCP (<100 x 10(9)/L) developed in 5% of patients; profound TCP (<20 x 10(9)/L) occurred in 2%. In patients who received abciximab within 1 month of a previous treatment (n = 115), the risk of developing TCP and profound TCP was 16.5% and 12.2%, respectively. Having a positive HACA before readministration was not correlated with adverse clinical outcomes or bleeding, but was associated with TCP (14.1% vs 4.4%, p = 0.002) and profound TCP (5.6% vs 1.6%, p = 0.036). Readministration of abciximab can be accomplished without severe allergic responses and with a bleeding and efficacy profile similar to first-time administration. However, the rate of severe and profound TCP is increased relative to first-time administration, particularly when the time between treatments is <30 days or when HACA is present.