Baseline Low-Density Lipoprotein Cholesterol and Clinical Outcomes of Combining Ezetimibe With Statin Therapy in IMPROVE-IT

Abstract

Background: The 2018 U.S. cholesterol management guideline recommends additional lipid-lowering therapy with ezetimibe for secondary prevention in very high-risk patients with low-density lipoprotein cholesterol (LDL-C) ≥70 mg/dL despite maximally tolerated statin.

Objectives: The purpose of this study was to evaluate the relationship between baseline LDL-C above and below 70 mg/dL and the benefit of adding ezetimibe to statin in patients post-acute coronary syndrome (ACS).

Methods: IMPROVE-IT (Improved Reduction of Outcomes: Vytorin Efficacy International Trial) was a double-blind, placebo-controlled, randomized trial of ezetimibe/simvastatin vs placebo/simvastatin in post-ACS patients followed for 6 years (median). A total of 17,999 patients were stratified by LDL-C at qualifying event into 3 groups (50-<70, 70-<100, and 100-125 mg/dL). The primary endpoint was a composite of cardiovascular death, major coronary events, or stroke.

Results: Absolute differences in median LDL-C achieved at 4 months between treatment arms were similar (17-20 mg/dL). The effect of ezetimibe/simvastatin vs placebo/simvastatin on primary endpoint was consistent regardless of baseline LDL-C of 50-<70 mg/dL (HR: 0.92 [95% CI: 0.80-1.05]), 70-<100 mg/dL (HR: 0.93 [95% CI: 0.87-1.01]), or 100-125 mg/dL (HR: 0.94 [95% CI: 0.86-1.03]; P interaction = 0.95). Normalized relative risk reductions per 1-mmol/L difference in achieved LDL-C at 4 months between treatment arms were 21% in patients with baseline LDL-C of 50-<70 mg/dL, 16% in those with 70-<100 mg/dL, and 13% in those with 100-125 mg/dL (P interaction = 0.91). No significant treatment interactions by baseline LDL-C were present for safety endpoints.

Conclusions: Adding ezetimibe to statin consistently reduced the risk for cardiovascular events in post-ACS patients irrespective of baseline LDL-C values, supporting the use of intensive lipid-lowering therapy with ezetimibe even in patients with baseline LDL-C <70 mg/dL. (IMPROVE-IT: Examining Outcomes in Subjects With Acute Coronary Syndrome: Vytorin [Ezetimibe/Simvastatin] vs Simvastatin [P04103]; NCT00202878).

Keywords: acute coronary syndrome; ezetimibe; low-density lipoprotein cholesterol; statin.

Conflict of interest statement

Funding Support and Author Disclosures The IMPROVE-IT trial was supported by Merck and Co. Dr Oyama has received a grant from JSPS Overseas Research Fellowships. Dr Giugliano has received grants from Amgen and Anthos Therapeutics; has received honoraria from Amgen, Centrix, Daiichi-Sankyo, Dr Reddy's Laboratories, Medical Education Resources, Medscape, Menarini, Pfizer, SAJA Pharmaceuticals, Servier, and Voxmedia; and has received consultant fees from Amarin, Amgen, Bayer, CryoLife, Daiichi-Sankyo, Esperion, Gilead, Hengrui, Inari, Pfizer, PhaseBio Pharmaceuticals, St Lukes, and Sanofi. Dr Blazing has received research support from Merck; has received consulting fees from Espirion (<$10,000); and has received indirect support from Sanofi through Duke Clinical Research Institute. Dr Park has received institutional research grant support through Brigham and Women’s Hospital from Abbott, Amgen, Anthos Therapeutics, AstraZeneca, Daiichi-Sankyo, Eisai, Intarcia, MedImmune, Merck, Novartis, Pfizer, Regeneron Pharmaceuticals, Inc, Roche, The Medicines Company, and Zora Biosciences. Dr Tershakovec is a former employee of Merck Sharp and Dohme Corp, a subsidiary of Merck and Co, Inc, and may own stock in the company. Dr Sabatine has received research grant support through Brigham and Women’s Hospital from Amgen, Anthos Therapeutics, AstraZeneca, Bayer, Daiichi-Sankyo, Eisai, Intarcia, IONIS, The Medicines Company, MedImmune, Merck, Novartis, Pfizer, and Quark Pharmaceuticals; and has received consulting fees from Althera, Amgen, Anthos Therapeutics, AstraZeneca, Bristol Myers Squibb, CVS Caremark, DalCor, Dr Reddy's Laboratories, Fibrogen, IFM Therapeutics, Intarcia, MedImmune, Merck, Moderna, and Novo Nordisk. Dr Cannon has received grant support and consulting fees from Amgen, Boehringer Ingelheim, Bristol Myers Squibb, Janssen, Pfizer, and Merck; has received grant support from Daiichi-Sankyo; and has received consulting fees from Aegerion, Alnylam, Amarin, Applied Clinical Therapeutics, Ascendia, Corvidia, HLS Therapeutics, Innovent, Kowa, Eli Lilly, and Rhoshan. Dr Braunwald has received research grants through the Brigham and Women’s Hospital from AstraZeneca, Daiichi-Sankyo, Merck, and Novartis; has served as a consultant for Amgen, Cardurion, MyoKardia, NovoNordisk, Boehringer Ingelheim/Lilly, IMMEDIATE, and Verve; and has performed uncompensated consultancies and lectures for The Medicines Company.

Copyright © 2021 American College of Cardiology Foundation. Published by Elsevier Inc. All rights reserved.