A Placebo-Controlled Trial of the Oral PCSK9 Inhibitor Enlicitide

BACKGROUND: Enlicitide decanoate, an oral proprotein convertase subtilisin-kexin type 9 (PCSK9) inhibitor, was shown to reduce low-density lipoprotein (LDL) cholesterol levels in a phase 2 trial; longer-term data are needed. METHODS: In this multinational, double-blind, randomized, placebo-controlled trial, we enrolled adults with a history of a major atherosclerotic cardiovascular disease event with an LDL cholesterol level of 55 mg per deciliter or higher and those who were at risk for a first atherosclerotic cardiovascular disease event with an LDL cholesterol level of 70 mg per deciliter or higher. Participants were assigned in a 2:1 ratio to receive enlicitide at a dose of 20 mg or placebo daily for 52 weeks. The primary end point was the mean percent change in LDL cholesterol level from baseline to week 24. Key secondary end points were the mean percent change in LDL cholesterol level at week 52 and the mean percent change in levels of non-high-density lipoprotein (non-HDL) cholesterol and apolipoprotein B and the percent change in lipoprotein(a) level at week 24. RESULTS: Of the 2909 participants in the intention-to-treat population, 1935 received enlicitide and 969 received placebo (5 did not receive enlicitide or placebo). The mean age of the participants was 63 years, and 39.3% were women. The mean (±SD) LDL cholesterol level at baseline was 96.1±38.9 mg per deciliter. The mean percent change in LDL cholesterol levels at week 24 was -57.1% (95% confidence interval [CI], -61.8 to -52.5) with enlicitide and 3.0% (95% CI, 0.9 to 5.1) with placebo, representing an adjusted between-group difference of -55.8 percentage points (95% CI, -60.9 to -50.7; P<0.001). The mean percent change in LDL cholesterol level at week 52, the mean percent changes in non-HDL cholesterol and apolipoprotein B levels at week 24, and the percent change in lipoprotein(a) levels at week 24 were significantly greater with enlicitide than with placebo (P<0.001 for all comparisons). The incidence of adverse events did not appear to differ between the groups. CONCLUSIONS: Among participants who had a history of or were at risk for a first atherosclerotic cardiovascular disease event, treatment with the oral PCSK9 inhibitor enlicitide resulted in significantly lower LDL cholesterol levels than placebo at 24 weeks. (Funded by MSD [Rahway, NJ]; CORALreef Lipids ClinicalTrials.gov number, NCT05952856.).