Comparative Study of ALX-0081 Versus GPIIb/IIIa Inhibitor in High Risk Percutaneous Coronary Intervention (PCI) Patients

Inclusion Criteria: * Have unstable angina or NSTEMI,or stable angina with at least 2 factors indicating a high risk PCI as follows: patient related: diabetic patients, renal failure (glomerular filtration rate \< 60), reduced left ventricular ejection fraction \< 35%, age \> 75 years, female gender and/or lesion/anatomy related: SYNTAX score \> 26, bifurcation lesions, multi-vessel disease, intracoronary thrombus. * Adequate hematological function including platelets \> 100000/mm3. * Body mass index (BMI) ≥18 kg/m2 and ≤ 35 kg/m2. * Aged ≥ 18 years old. * Women of childbearing potential must be practicing a medically acceptable contraceptive regimen. Only males who do not want to father children during the study and in the first 4 months after treatment may be included in the study. During this period, safe contraception is mandatory. Male patients who are sexually active must use a condom during intercourse and ensure that the female partner uses a reliable contraceptive method, or they must refrain from sexual intercourse during the first 4 months after treatment. * Patients must be accessible for follow-up. * Have a sufficient command to read and understand all instructions necessary for giving informed consent and participating in the study. * Have signed and dated written informed consent prior to any study-related procedures. Exclusion Criteria: * Previous (within 30 days) treatment with GPIIb/IIIa inhibitors (such as ReoPro®). * ST-elevation myocardial infarction (STEMI). * Chronic total occlusion of a coronary artery. * Scheduled rotablator procedure. * PCI of the arterial or venous by-pass graft. * Any contra-indication for ReoPro®. * Major organ dysfunction, infection or any serious underlying medical condition that would impair the ability of the patient to receive protocol treatment. * Known hypersensitivity to human/humanized antibodies. * Women who are pregnant or lactating. * Dementia or significantly altered mental status that would prohibit understanding the study procedures and giving informed consent. * Use of vitamin K antagonists and/or Factor Xa inhibitors within 4 weeks prior to admission to the Hospital Intensive Care Unit. * Use of GPIIa/IIIb inhibitors other than ReoPro®; prasugrel, bivalirudin and fondaparinux prior to and throughout the study. * Known history of acquired or congenital bleeding disorder, coagulopathy or platelet disorder. * Evidence of active pathological bleeding at screening or history of clinically significant bleeding (such as gastrointestinal or genitourinary) within the last 6 months prior to screening visit, unless the cause has been definitely corrected * History of intracranial bleeding (e.g. hemorrhagic stroke, subdural hematoma, subarachnoid hemorrhage) or history of hemorrhagic retinopathy. * History of ischemic stroke or TIA, within the past year prior to screening or known structural cerebral vascular lesion (e.g. arteriovenous malformation, aneurysm). * History of New York Heart Association class III or IV congestive heart failure or history of severe, uncontrolled cardiac arrhythmias at screening. * Planned elective surgical operation or major invasive procedures or traumas from 30 days prior to screening to completion of the study at Day 30 (the decision of what constitutes a major invasive procedure or trauma will be at the discretion of the investigator in conjunction with review and approval by the Medical Monitor). * Use of another investigational drug or device within previous 30 days (12 weeks for investigational devices, e.g. unapproved stents) prior to screening.