Effect of APOC3 Inhibition with Olezarsen on Coronary Atherosclerosis: Essence–TIMI 73b Imaging Study

BACKGROUND: Whether lowering triglyceride-rich lipoproteins and remnant cholesterol favorably modifies coronary atherosclerosis is unclear. Olezarsen, an antisense oligonucleotide that targets apolipoprotein C-III, reduces triglycerides by ~60% and remnant cholesterol by ~70%, has a neutral effect on LDL cholesterol (LDL-C), and reduces apolipoprotein B (apoB) by ~15% in moderate hypertriglyceridemia. We investigated the effect of olezarsen on coronary plaque in adults with largely moderate hypertriglyceridemia. METHODS: We conducted a coronary computed tomography angiography (CCTA) study within Essence-TIMI 73b, a randomized, placebo-controlled trial of olezarsen vs. placebo that enrolled patients between November 2022 and February 2024. Inclusion criteria were triglycerides ≥150 mg/dL (2.26 mmol/L), presence or high risk for cardiovascular disease, and non-calcified plaque on baseline CCTA. The primary endpoint was percent change from baseline to 12 months in non-calcified plaque volume (NCPV). RESULTS: Of 468 participants (349 olezarsen, 119 placebo), the median age was 63 years (IQR 56-70); 31% were women, and 97% received lipid-lowering therapy. Median baseline triglycerides were 249 mg/dL (IQR 197-331), and remnant cholesterol was 53 mg/dL (IQR 38-76). Median baseline NCPV was 125.3 mm³ (IQR 63.2-213.3). At 6 months, olezarsen reduced triglycerides by 63.9%, remnant cholesterol by 71.9%, and apolipoprotein B by 16.0% over placebo, with no difference in LDL-C. The percent change in NCPV with olezarsen from baseline to month 12 did not differ between olezarsen and placebo (placebo-adjusted least-squares mean difference 2.98%; 95% CI -3.4 to 9.3; p=0.36). No significant differences between olezarsen and placebo were observed for changes in low-attenuation, calcified, or total plaque volumes at 12 months. CONCLUSIONS: Despite substantial triglyceride and remnant cholesterol lowering, treatment with olezarsen for 12 months on top of standard-of-care lipid-lowering therapy in patients with largely moderate hypertriglyceridemia did not affect noncalcified coronary plaque volume.