# Detailed HORIZON Results Show No Heart-Event Benefit From Pelacarsen

The Cleveland Clinic-led trial found similar major cardiovascular event rates with pelacarsen and placebo, despite lower lipoprotein(a) levels.

By Will Langan | 24X7 News
Published: 2026-11-07T16:10:14.167Z
Updated: 2026-11-07T16:11:42.433Z
Section: Health
Format: News
Canonical: https://24x7news.us/articles/horizon-pelacarsen-detailed-heart-trial-results-november-7-2026

Detailed results from the HORIZON clinical trial, presented in Chicago on Saturday, November 7, showed that pelacarsen lowered lipoprotein(a) levels but did not reduce major cardiovascular events over 4.7 years of follow-up, according to Cleveland Clinic.

The institution reported that the trial’s main combined outcome occurred in 12.3% of participants receiving pelacarsen and 12.1% receiving placebo. That outcome included cardiovascular death, heart attack, stroke or an urgent procedure to restore coronary blood flow requiring hospitalization.

Cleveland Clinic said the findings were presented at the American Heart Association’s Scientific Sessions and published simultaneously in the New England Journal of Medicine. It also reported mild side effects and rare allergic reactions.

The neutral headline result was first announced September 4. Saturday’s presentation supplies detailed findings from the study; it does not mark the first disclosure that the trial missed its primary endpoint.

Sponsor Novartis described HORIZON as a randomized, double-blind, placebo-controlled phase 3 trial involving 8,323 people with elevated lipoprotein(a) and established cardiovascular disease. Participants were receiving standard treatments, including medicines to lower lipids and blood pressure.

Pelacarsen is an experimental antisense oligonucleotide intended to inhibit production of lipoprotein(a). Novartis licensed global development, manufacturing and commercialization rights from Ionis Pharmaceuticals.

Senior author Steven Nissen, Cleveland Clinic’s chief academic officer for its Heart, Vascular & Thoracic Institute, cautioned that one trial does not settle whether lowering lipoprotein(a) can reduce cardiovascular risk. The finding establishes the result for this treatment in the population studied, while leaving broader questions for further research.

Sources:
Cleveland Clinic — Detailed HORIZON results, November 7.
Novartis — September 4 headline-results announcement, background.
American Heart Association — November 7 late-breaking science program.

## Sources
- Cleveland Clinic — Detailed HORIZON results, November 7: https://newsroom.clevelandclinic.org/2026/11/07/cleveland-clinic-trial-shows-novel-lipoproteina-drug-did-not-reduce-major-cardiovascular-events-after-nearly-5-years
- Novartis — September 4 headline results, background: https://www.novartis.com/us-en/news/media-releases/novartis-announces-lpahorizon-phase-iii-topline-results-pelacarsen-patients-elevated-lpa-and-established-cardiovascular-disease-cvd
- American Heart Association — November 7 late-breaking science session, 8:30–9:45 a.m. Central: https://professional.heart.org/en/meetings/scientific-sessions/programming/late-breaking-science
- Image — HealthMonitor, Cleveland Clinic Crile Building, CC BY-SA 4.0: https://commons.wikimedia.org/wiki/File:Cleveland_Clinic_Crile_Building.jpg
- Image license — CC BY-SA 4.0; branding added: https://creativecommons.org/licenses/by-sa/4.0/