Effects of routine early treatment with PCSK9 inhibitors in patients undergoing primary percutaneous coronary intervention for ST-segment elevation myocardial infarction: a randomised, double-blind, sham-controlled trial

Background: In patients with ST-segment elevation myocardial infarction (STEMI), early initiation of high-intensity statin therapy, regardless of low-density lipoprotein (LDL) cholesterol levels, is the standard of practice worldwide. 

Aims: We sought to determine the effect of a similar early initiation strategy, using a proprotein convertase subtilisin/kexin type 9 (PCSK9) inhibitor added to the high-intensity statin, on LDL cholesterol in acute STEMI.

Methods: In a randomised, double-blind trial we assigned 68 patients with STEMI undergoing primary percutaneous coronary intervention (PCI) to early treatment with alirocumab 150 mg subcutaneously or to a matching sham control. The first injection was given before primary PCI regardless of the baseline LDL level, then at 2 and 4 weeks. The primary outcome was the percent reduction in direct LDL cholesterol up to 6 weeks, analysed using a linear mixed model.  

Results: High-intensity statin use was 97% and 100% in the alirocumab and sham-control groups, respectively. At a median of 45 days, the primary outcome of LDL cholesterol decreased by 72.9% with alirocumab (2.97 mmol/L to 0.75 mmol/L) versus 48.1% with the sham control (2.87 mmol/L to 1.30 mmol/L), for a mean between-group difference of –22.3% (p<0.001). More patients achieved the European Society of Cardiology/European Atherosclerosis Society dyslipidaemia guideline target of LDL ≤1.4 mmol/L in the alirocumab group (92.1% vs 56.7%; p<0.001). Within the first 24 hours, LDL declined slightly more rapidly in the alirocumab group than in the sham-control group (–0.01 mmol/L/hour; p=0.03) with similar between-group mean values. 

Conclusions: In this randomised trial of routine early initiation of PCSK9 inhibitors in patients undergoing primary PCI for STEMI, alirocumab reduced LDL cholesterol by 22% compared with sham control on a background of high-intensity statin therapy. A large trial is needed to determine if this simplified approach followed by long-term therapy improves cardiovascular outcomes in patients with acute STEMI. (ClinicalTrials.gov: NCT03718286)