On September 4, 2026, Ionis Pharmaceuticals, Inc. reported that its partner, Novartis, announced that the pelacarsen Phase 3 Lp(a)HORIZON study did not meet its primary endpoint. The study was a cardiovascular outcomes trial designed to evaluate the effect of pelacarsen on the incidence of major adverse cardiovascular events (MACE).
The primary endpoint was a composite of cardiovascular death, non-fatal myocardial infarction, non-fatal stroke, and urgent coronary revascularization requiring hospitalization. The trial evaluated these outcomes in an overall population of patients with lipoprotein (a) levels of 70 mg/dL or higher and a subpopulation with levels of 90 mg/dL or higher.
The study included 8,323 patients with elevated Lp(a) and established cardiovascular disease who received guideline-directed treatments, including lipid-lowering and antihypertensive therapies.
Despite the failure to meet the primary endpoint, the filing notes that pelacarsen achieved substantially lower lipoprotein (a) levels consistent with previous studies. The company stated that the drug demonstrated an acceptable safety profile. The full data from the Lp(a)HORIZON study will be presented at an upcoming medical congress.
Ionis discovered and conducted the early development of pelacarsen. In February 2019, Novartis exercised an option to license the rights to develop and commercialize pelacarsen for targeted cardiovascular therapy.
