BACKGROUND: Cholesterol reduction with proprotein convertase subtilisin-kexin type 9 inhibitors reduces ischemic events; however, the cost-effectiveness in statin-treated patients with recent acute coronary syndrome remains uncertain. OBJECTIVES: This study sought to determine whether further cholesterol reduction with alirocumab would be cost-effective in patients with a recent acute coronary syndrome on optimal statin therapy. METHODS: A cost-effectiveness model leveraging patient-level data from ODYSSEY OUTCOMES (Evaluation of Cardiovascular Outcomes After an Acute Coronary Syndrome During Treatment With Alirocumab) was developed to estimate costs and outcomes over a lifetime horizon. Patients (n = 18,924) had a recent acute coronary syndrome and were on high-intensity or maximum-tolerated statin therapy, with a baseline low-density lipoprotein cholesterol (LDL-C) level ≥70 mg/dl, non-high-density lipoprotein cholesterol ≥100 mg/dl, or apolipoprotein B ≥80 mg/l. Alirocumab 75 mg or placebo was administered subcutaneously every 2 weeks. Alirocumab was blindly titrated to 150 mg if LDL-C remained ≥50 mg/dl or switched to placebo if 2 consecutive LDL-C levels were <15 mg/dl. Incremental cost per quality-adjusted life-year (QALY) was determined with the addition of alirocumab versus placebo and, based on clinical efficacy findings from the trial, was stratified by baseline LDL-C levels ≥100 mg/dl and <100 mg/dl. RESULTS: Across the overall population recruited to the ODYSSEY OUTCOMES trial, using an annual treatment cost of US$5,850, the mean overall incremental cost-effectiveness ratio was US$92,200 per QALY (base case). The cost was US$41,800 per QALY in patients with baseline LDL-C ≥100 mg/dl, whereas in those with LDL-C <100 mg/dl the cost per QALY was US$299,400. Among patients with LDL-C ≥100 mg/dl, incremental cost-effectiveness ratios remained below US$100,000 per QALY across a wide variety of sensitivity analyses. CONCLUSIONS: In patients with a recent acute coronary syndrome on optimal statin therapy, alirocumab improves cardiovascular outcomes at costs considered intermediate value, with good value in patients with baseline LDL-C ≥100 mg/dl but less economic value with LDL-C <100 mg/dl. (Evaluation of Cardiovascular Outcomes After an Acute Coronary Syndrome During Treatment With Alirocumab [ODYSSEY OUTCOMES]; NCT01663402).