For a study, researchers sought to assess the impact of alirocumab on coronary atherosclerosis in patients with acute myocardial infarction using serial multimodality intracoronary imaging. The PACMAN-AMI clinical trial was a double-blind, placebo-controlled, randomized study (enrollment: May 9, 2017, through October 7, 2020; final follow-up: October 13, 2021). At nine academic hospitals, 300 patients undergoing percutaneous coronary intervention for acute myocardial infarction were recruited. Patients were randomly assigned to receive biweekly subcutaneous alirocumab (150 mg; n=148) or placebo (n=152) for 52 weeks, beginning less than 24 hours following the urgent percutaneous coronary intervention of the culprit lesion and continuing with high-intensity statin treatment (rosuvastatin, 20 mg). At baseline and 52 weeks, intravascular ultrasonography (IVUS), near-infrared spectroscopy, and optical coherence tomography were done serially in the two non–infarct-related coronary arteries. The change in IVUS-derived percent atheroma volume from baseline to week 52 was the major efficacy end measure. Changes in near-infrared spectroscopy–derived maximum lipid core burden index within 4 mm (higher values indicating greater lipid content) and optical coherence tomography–derived minimal fibrous cap thickness (smaller values indicating thin-capped, vulnerable plaques) from baseline to week 52 were two powered secondary endpoints.
About 265 (88.3%) of 300 randomized patients (mean [SD] age, 58.5 [9.7]; 56 [18.7%] women; mean [SD] low-density lipoprotein cholesterol level, 152.4 [33.8] mg/dL) had serial IVUS imaging in 537 arteries. At 52 weeks, the mean change in percent atheroma volume with alirocumab was (−2.13% vs −0.92% ) with placebo (difference, −1.21% [95% CI, −1.78% to −0.65%], P<.001). The mean difference in maximal lipid core burden index within 4 mm with alirocumab was −79.42 vs −37.60 with placebo (difference, −41.24 [95% CI, −70.71 to −11.77]; P = .006). The mean decrease in minimum fibrous cap thickness with alirocumab was 62.67 μm vs 33.19 μm with placebo (difference, 29.65 μm [95% CI, 11.75-47.55]; P = .001). Adverse events occurred in 70.7% of alirocumab patients vs 72.8% of placebo patients.
When compared to placebo, adding subcutaneous biweekly alirocumab to high-intensity statin treatment resulted in significantly higher coronary plaque regression in non–infarct-related arteries after 52 weeks in individuals with acute myocardial infarction. More study was required to determine whether alirocumab improves clinical outcomes in the patient population.