Abciximab binds to the intact platelet GPIIb/IIIa receptor, which is a member of the integrin family of adhesion receptors and the major platelet surface receptor involved in platelet aggregation. This binding is thought to involve steric hindrance and/or conformational alterations which block access of large molecules to the receptor rather than direct interaction with the RGD (arginine-glycine-aspartic acid) binding site of GPIIb/IIIa. By binding to the vitronectin receptor (also known as the αvβ3 integrin), abciximab blocks effects mediated by this integrin which include cell adhesion. Furthermore, abciximab blocks Mac-1 receptor on monocytes and neutrophils thus inhibiting monocyte adhesion.
Abciximab is indicated for use in individuals undergoing percutaneous coronary intervention (angioplasty with or without stent placement). The use of abciximab in this setting is associated with a decreased incidence of ischemic complications due to the procedure and a decreased need for repeated coronary artery revascularization in the first month following the procedure. Research also shows that this drug can be of use for patients with diabetes and chronic renal insufficiency. It is not the appropriate drug of choice if a patient is scheduled for an emergency surgery (i.e., heart surgery) because bleeding time may take about 12 hours to normalize.
Abciximab has the potential to increase the risk of bleeding, particularly in the presence of anticoagulation, e.g., from heparin, other anticoagulants or thrombolytics. Bleeding in the Phase 3 trials was classified as major, minor or insignificant by the criteria of the Thrombolysis in Myocardial Infarction study group (16). Major bleeding events were defined as either an intracranial hemorrhage or a decrease in hemoglobin greater than 5 g/dL. Minor bleeding events included spontaneous gross hematuria, spontaneous hematemesis, observed blood loss with a hemoglobin decrease of more than 3 g/dL, or a decrease in hemoglobin of at least 4 g/dL without an identified bleeding site. Insignificant bleeding events were defined as a decrease in hemoglobin of less than 3 g/dL or a decrease in hemoglobin between 3-4 g/dL without observed bleeding. In patients who received transfusions, the number of units of blood lost was estimated through an adaptation of the method of Landefeld, et al. (17).
In the EPIC trial, in which a non-weight-adjusted, longer-duration heparin dose regimen was used, the most common complication during Abciximab therapy was bleeding during the first 36 hours. The incidences of major bleeding, minor bleeding and transfusion of blood products were significantly increased. Major bleeding occurred in 10.6% of patients in the Abciximab bolus plus infusion arm compared with 3.3% of patients in the placebo arm. Minor bleeding was seen in 16.8% of Abciximab bolus plus infusion patients and 9.2% of placebo patients (7). Approximately 70% of Abciximab-treated patients with major bleeding had bleeding at the arterial access site in the groin. Abciximab-treated patients also had a higher incidence of major bleeding events from gastrointestinal, genitourinary, retroperitoneal, and other sites.
Bleeding rates were reduced in the CAPTURE trial, and further reduced in the EPILOG and EPISTENT trials by use of modified dosing regimens and specific patient management techniques. In EPILOG and EPISTENT, using the heparin and Abciximab dosing, sheath removal and arterial access site guidelines described under PRECAUTIONS, the incidence of major bleeding in patients treated with Abciximab and low-dose, weight-adjusted heparin was not significantly different from that in patients receiving placebo.
Subgroup analyses in the EPIC and CAPTURE trials showed that non-CABG major bleeding was more common in Abciximab patients weighing ≤ 75 kg. In the EPILOG and EPISTENT trials, which used weight-adjusted heparin dosing, the non-CABG major bleeding rates for Abciximab-treated patients did not differ substantially by weight subgroup.
Although data are limited, Abciximab treatment was not associated with excess major bleeding in patients who underwent CABG surgery. (The range among all treatment arms was 3-5% in EPIC, and 1-2% in the CAPTURE, EPILOG, and EPISTENT trials.) Some patients with prolonged bleeding times received platelet transfusions to correct the bleeding time prior to surgery.
The rates of major bleeding, minor bleeding and bleeding events requiring transfusions in the CAPTURE, EPILOG, and EPISTENT trials are shown in Table 4. The rates of insignificant bleeding events are not included in Table 4.
Cases of fatal bleeding have been reported rarely during post-marketing use of Abciximab
Pulmonary alveolar hemorrhage has been rarely reported during use of Abciximab. This can present with any or all of the following in close association with ReoPro administration: hypoxemia, alveolar infiltrates on chest x-ray, hemoptysis, or an unexplained drop in hemoglobin.
Intracranial Hemorrhage And Stroke
The total incidence of intracranial hemorrhage and non-hemorrhagic stroke across all four trials was not significantly different, 9/3023 for placebo patients and 15/4680 for Abciximab-treated patients. The incidence of intracranial hemorrhage was 3/3023 for placebo patients and 7/4680 for Abciximab patients.
In the clinical trials, patients treated with Abciximab were more likely than patients treated with placebo to experience decreases in platelet counts. Among patients in the EPILOG and EPISTENT trials who were treated with Abciximab plus low-dose heparin, the proportion of patients with any thrombocytopenia (platelets less than 100,000 cells/μL) ranged from 2.5 to 3.0%. The incidence of severe thrombocytopenia (platelets less than 50,000 cells/μL) ranged from 0.4 to 1.0% and platelet transfusions were required in 0.9 to 1.1%, respectively. Modestly lower rates were observed among patients treated with placebo plus standard-dose heparin. Overall higher rates were observed among patients in the EPIC and CAPTURE trials treated with Abciximab plus longer duration heparin: 2.6 to 5.2% were found to have any thrombocytopenia, 0.9 to 1.7% had severe thrombocytopenia, and 2.1 to 5.5% required platelet transfusion, respectively.
The following additional adverse events from the EPIC, EPILOG and CAPTURE trials were reported by investigators for patients treated with a bolus plus infusion of Abciximab at incidences which were less than 0.5% higher than for patients in the placebo arm.
Cardiovascular System: ventricular tachycardia (1.4%), pseudoaneurysm (0.8%), palpitation (0.5%), arteriovenous fistula (0.4%), incomplete AV block (0.3%), nodal arrhythmia (0.2%), complete AV block (0.1%), embolism (limb)(0.1%); thrombophlebitis (0.1%);
Gastrointestinal System: dyspepsia (2.1%), diarrhea (1.1%), ileus (0.1%), gastroesophogeal reflux (0.1%);
Hemic and Lymphatic System: anemia (1.3%), leukocytosis (0.5%), petechiae (0.2%);
Nervous System: dizziness (2.9%), anxiety (1.7%), abnormal thinking (1.3%), agitation (0.7%), hypesthesia (0.6%), confusion (0.5%) muscle contractions (0.4%), coma (0.2%), hypertonia (0.2%), diplopia (0.1%);
Respiratory System: pneumonia (0.4%), rales (0.4%), pleural effusion (0.3%), bronchitis (0.3%) bronchospasm (0.3%), pleurisy (0.2%), pulmonary embolism (0.2%), rhonchi (0.1%);
Musculoskeletal System: myalgia (0.2%);
Urogenital System: urinary retention (0.7%), dysuria (0.4%), abnormal renal function (0.4%), frequent micturition (0.1%), cystalgia (0.1%), urinary incontinence(0.1%), prostatitis (0.1%);
Miscellaneous: pain (5.4%), sweating increased (1.0%), asthenia (0.7%), incisional pain (0.6%), pruritus (0.5%), abnormal vision (0.3%), edema (0.3%), wound (0.2%), abscess (0.2%), cellulitis (0.2%), peripheral coldness (0.2%), injection site pain (0.1%), dry mouth (0.1%), pallor (0.1%), diabetes mellitus (0.1%), hyperkalemia (0.1%), enlarged abdomen (0.1%), bullous eruption (0.1%), inflammation (0.1%), drug toxicity (0.1%).
As with all therapeutic proteins, there is a potential for immunogenicity. In the EPIC, EPILOG, and CAPTURE trials, positive HACA responses occurred in approximately 5.8% of these patients receiving a first exposure to Abciximab. No increase in hypersensitivity or allergic reactions was observed with Abciximab treatment.
The safety and efficacy of Abciximab have only been investigated with concomitant administration of heparin and aspirin as described in Clinical Studies.
In patients with failed PCIs, the continuous infusion of Abciximab should be stopped because there is no evidence for Abciximab efficacy in that setting.
In the event of serious bleeding that cannot be controlled by compression, Abciximab and heparin should be discontinued immediately.
The recommended dosage of Abciximab in adults is a 0.25 mg/kg intravenous bolus administered 10-60 minutes before the start of PCI, followed by a continuous intravenous infusion of 0.125 μg/kg/min (to a maximum of 10 μg/min) for 12 hours.
Patients with unstable angina not responding to conventional medical therapy and who are planned to undergo PCI within 24 hours may be treated with an Abciximab 0.25.mg/kg intravenous bolus followed by an 18- to 24-hour intravenous infusion of 10 μg/min, concluding one hour after the PCI.
Formal drug interaction studies with Abciximab have not been conducted. Abciximab has been administered to patients with ischemic heart disease treated concomitantly with a broad range of medications used in the treatment of angina, myocardial infarction and hypertension. These medications have included heparin, warfarin, beta-adrenergic receptor blockers, calcium channel antagonists, angiotensin converting enzyme inhibitors, intravenous and oral nitrates, ticlopidine, and aspirin. Heparin, other anticoagulants, thrombolytics, and antiplatelet agents are associated with an increase in bleeding. Patients with HACA titers may have allergic or hypersensitivity reactions when treated with other diagnostic or therapeutic monoclonal antibodies.
If you miss a dose of abciximab, take it as soon as possible. However, if it is almost time for your next dose, skip the missed dose and take your regular dose as scheduled. Do not take a double dose.
Abciximab has the potential to increase the risk of bleeding events, rarely including those with a fatal outcome, particularly in the presence of anticoagulation, e.g., from heparin, other anticoagulants, or thrombolytics
The risk of major bleeds due to Abciximab therapy is increased in patients receiving thrombolytics and should be weighed against the anticipated benefits.
Should serious bleeding occur that is not controllable with pressure, the infusion of Abciximab and any concomitant heparin should be stopped.
Allergic Reactions (including anaphylaxis)
Allergic reactions, some of which were anaphylaxis (sometimes fatal), have been reported rarely in patients treated with ReoPro. Patients with allergic reactions should receive appropriate treatment. Treatment of anaphylaxis should include immediate discontinuation of ReoPro administration and initiation of resuscitative measures.