Abciximab

Some of the views expressed in the following notes on newly approved products should be regarded as preliminary, as there may have been limited published data at the time of publication, and little experience in Australia of their safety or efficacy. However, the Editorial Executive Committee believes that comments made in good faith at an early stage may still be of value. Before new drugs are prescribed, the Committee believes it is important that more detailed information is obtained from the manufacturer's approved product information, a drug information centre or some other appropriate source.

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ReoPro (Eli Lilly Australia)
2 mg/mL in 5 mL and 20 mL glass vials
Indication: coronary angioplasty

Abciximab has been approved for patients who have a high risk of developing acute vessel closure as a complication of coronary angioplasty. Patients who are especially at risk include those with a myocardial infarction or unstable angina, and those with lesions which have particular morphological characteristics. Abciximab is added to the routine use of heparin and aspirin.

The beneficial effects of abciximab are due to its inhibition of platelet aggregation. Abciximab is an IgG antibody directed against glycoprotein receptors on the surface of platelets. It prevents fibrinogen from binding to activated platelets.

Abciximab is given as an intravenous bolus followed by an infusion over 12 hours. The drug binds rapidly to platelets and blocks at least 80% of the receptors. During the infusion, the bleeding time can exceed 30 minutes.

In a multi centre, double-blind trial, 2099 patients undergoing coronary angioplasty were given aspirin, heparin and either abciximab or a placebo. The endpoints of the study were death, myocardial infarction, coronary artery bypass surgery or a need for revascularisation. In the first 48 hours after angioplasty or atherectomy, patients given placebo were more likely to have had these adverse outcomes.

As at least 30% of patients develop a restenosis within 6 months, the outcomes were also analysed after that interval. Fewer patients in the treatment group had an infarction or required revascularisation. The absolute difference in major ischaemic events/revascularisation was 8.1% (35.1% placebo vs. 27% active treatment).¹

Although abciximab reduces restenosis, it can also cause major bleeding in 10-20% of patients. In the study,¹ the patients given abciximab had a significant increase in bleeding complications in the first 48 hours. This may be because platelet function takes 24-48 hours to recover after the infusion stops. The bleeding is usually from the femoral artery access site; however, intracranial, retroperitoneal, gastrointestinal or genitourinary haemorrhage can occur. Some patients will develop thrombocytopenia.

At present, it is not clear if the cost of treatment (approximately $1500 per patient) and its complications will be offset by the benefits of abciximab.