ReoPro Readministration Registry - R3

Description:

Abciximab re-administration for patients undergoing percutaneous interventions.

Hypothesis:

To evaluate the outcomes of patients receiving multiple doses of ReoPro (abciximab).

Study Design

Study Design:

Patients Screened: 23,453
Patients Enrolled: 500

Patient Populations:

All patients retreated with abciximab for coronary interventions, representing approximately 2% of the total angioplasty experience (n=23,453) at 22 sites

Primary Endpoints:

Procedural and hospital outcomes

Secondary Endpoints:

Adverse allergic and clinical events (baseline and 2 months), and incidence of thrombocytopenia;
Anti-chimeric antibody data accrued at baseline, 5 days, 4 weeks, and 8 weeks in the first 374 registry patients, with abciximab IC50 determinations made in HACA (+) sera

Drug/Procedures Used:

Abciximab re-administration for percutaneous interventions.

Principal Findings:

R³ (pronounced R-cubed) is a serial patient registry (22 U.S. sites) designed to assess potential antigenicity associated with retreatment of the monoclonal antibody Fab fragment abciximab (ReoPro) as an adjunct to coronary intervention.

Of the 500 patients who were readministered abciximab, 7% received the agent ≥3 times. There was no fall-off in efficacy following readministration, with this group showing an overall clinical success rate of 93.6%; and no statistically significant difference in success rates for those receiving the drug 2 or 3 times.

Analysis of adverse clinical events revealed no deaths, no cases of allergic or hypersensitivity reactions, no anaphylactic-type reactions, and no incidences of retroperitoneal or intracranial hemorrhage. There was a 1% incidence of abrupt closure and a reported 3.2% incidence of myocardial infarction, effecting a total of 16 patients. Urgent revascularization was required only in 4 patients, of which 3 underwent angioplasty and 1 underwent urgent bypass surgery. Access site bleeding requiring therapy was noted in 2.2% of patients.

All 500 patients underwent platelet count assessment 4-6 hours after bolus administration of abciximab and were re-measured 24 hours later. Twenty-two patients (4.4%) developed thrombocytopenia, defined as a drop in platelet counts to <100,000 and at least a 25% decrease from baseline. Seven patients (1.4%) showed a nadir of 50,000 to 100,000, 4 patients (0.8%) had a nadir of 20,000 to 50,000, and 11 patients (2.2%) developed profound thrombocytopenia with a nadir <20,000. For comparison purposes, pooled data from the EPIC, EPILOG, and CAPTURE trials suggest that first time administration of abciximab is associated with thrombocytopenia in approximately 3.7% of patients vs. 2.0% in placebo controls.

HACA data were available for the first 374 patients, 23 (7%) of whom showed HACA titers. HACA did not neutralize abciximab, nor was a positive titer predictive of a lack of clinical effectiveness, thrombocytopenia, or other clinical sequelae.

Interpretation:

Approximately 6-7% of patients receiving abciximab develop a human anti-chimeric antibody (HACA) after first administration. In addition, about 1% of abciximab-treated patients develop profound thrombocytopenia (a platelet count <20,000). This has led to concerns regarding the safety and efficacy of abciximab readministration. The R³ investigators concluded that indications for use and patient management algorithms (particularly with respect to heparin dosing and vascular sheath management) should remain the same whether abciximab is given for the first time or as a retreatment.

References:

1. Circulation 1998;98:(Abstr Suppl):I-17

Clinical Topics: Anticoagulation Management, Invasive Cardiovascular Angiography and Intervention

Keywords: Myocardial Infarction, Platelet Aggregation Inhibitors, Platelet Count, Heparin, Retreatment, Immunoglobulin Fab Fragments, Angioplasty, Intracranial Hemorrhages, Research Personnel, Thrombocytopenia


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