Proof of Mechanism Study of MLN1202 on Atherosclerotic Inflammation in Participants With Stable Atherosclerotic Cardiovascular Disease

Inclusion Criteria: 1. The participant or, when applicable, the participant's legally acceptable representative signs and dates a written, informed consent form (including consent for pharmacogenomics \[PGx\] collection) and any required privacy authorization prior to the initiation of any study procedures. 2. Is male or female and aged 35 to 80 years, inclusive at Screening. 3. Has documented atherosclerotic vascular disease (eg, coronary artery disease (CAD), peripheral arterial disease, aortic atherosclerosis or abdominal aortic aneurysm (\<5 cm), carotid disease, or cerebrovascular disease) and has been clinically stable for at least 3 months prior to Screening. Documentation sufficient to demonstrate presence of atherosclerotic vascular disease will include one or more of the following: * i. History of myocardial infarction. * ii. History of stroke. * iii. Framingham score indicating \>20% 10-year risk in an individual who is age \>55. * iv. Documentation of atherosclerotic disease by objective diagnostic testing. 4. Are willing to undergo 2, 2-deoxy-2-\[\^18F\]-fluoro-D-g1ucose positron emission tomography (FDG PET)/CT scans, have a body weight compatible with their imaging center's PET/CT scanner table limits and be able to tolerate the imaging procedure. 5. Are statin naïve or are taking a stable statin dose AND, if taking a statin, are not on a high dose of a high-potency statin. A high-dose of high potency statin is defined as atorvastatin ≥40 mg/day or rosuvastatin ≥20 mg/day. Furthermore, statin dose must be stable for at least 6 weeks prior to Screening FDG PET /CT scan and must not be changed during the remainder of the study. Exclusion Criteria: 1. Has a history or clinical manifestations of: * a) Type 1 diabetes mellitus. * b) Significant heart failure (eg, New York Heart Association class III or IV). * c) Active or chronic liver disease. * d) Any chronic systemic inflammatory condition requiring ongoing therapy with anti-inflammatory drugs. * e) Any history of cancer, except basal cell carcinoma which has been in remission for at least 5 years prior to Day 1 of this study. * f) Any infection requiring antibiotic therapy within 6 weeks prior to Screening FDG PET/CT. * g) Any acute infection within 2 weeks of Screening FDG PET/CT scan. * h) Impaired renal function (estimated creatinine clearance \<60 ml/min as calculated by the Cockcroft Gault formula). Re-testing may be allowed on a case by case basis. 2. Requires ongoing therapy with any systemic anti-inflammatory drugs (except nonsteroidal anti-inflammatory drug \[NSAIDs\]), including systemic anti-inflammatory steroids, methotrexate, colchicine, anti-inflammatory biologics, or any other compound that in the opinion of the investigator has a substantial anti-inflammatory effect. 3. Has received treatment with systemic immunosuppressant or systemic anti- inflammatory medications within 6 weeks prior to Screening FDG PET/CT scan. 4. Has a history of hypersensitivity or allergies to any component of the study medication or history of hypersensitivity to monoclonal antibodies. 5. Has any significant medical condition(s) which, in the investigator's opinion, may interfere with the participant's optimal participation in the study. 6. Has poorly controlled blood glucose, defined for the purposes of this study as glycosylated hemoglobin (HbA1c) ≥7.75% at Screening. 7. Screening FDG PET/CT scan has inadequate vascular uptake (target to background ratio \[TBR\] \<1.6) in all of the index vessels (ascending aorta, left carotid, right carotid) as assessed by the imaging core laboratory.