Novartis said its investigational drug pelacarsen lowered lipoprotein(a), a blood particle linked to cardiovascular risk, but did not significantly reduce major cardiovascular events in its pivotal Phase III trial. The result is an important setback for a drug program designed to test whether directly lowering Lp(a) can improve outcomes for people who already have cardiovascular disease and receive standard preventive care.
The company announced the topline findings September 4 from Lp(a)HORIZON, a global trial enrolling 8,323 patients with elevated Lp(a) and established cardiovascular disease. Participants received pelacarsen or placebo alongside guideline-directed treatment, including lipid-lowering and antihypertensive medicines. Novartis said the trial missed its primary endpoint in the overall study population, even though Lp(a) concentrations were lower among people given pelacarsen.
What Lp(a)HORIZON tested
Lipoprotein(a), generally shortened to Lp(a), is a type of cholesterol-carrying particle. Its level is largely determined by genes and does not meaningfully fall with diet and exercise, as CNBC reported in its coverage of the trial result. Novartis estimates that elevated Lp(a) affects about one in five people worldwide, and no targeted Lp(a) treatment has been approved.
Pelacarsen is an antisense oligonucleotide, a medicine designed to interfere with genetic instructions involved in producing Lp(a). The trial was randomized, double-blind and placebo-controlled, features intended to determine whether adding the drug causes a difference in clinical outcomes compared with usual care alone. The study was not simply asking whether the medicine changed a laboratory value; it was designed to determine whether treatment altered patients’ risk of serious cardiovascular events.
The trial’s reported composite endpoint included cardiovascular death, nonfatal heart attack, nonfatal stroke and urgent coronary revascularization requiring hospitalization. Novartis’ announcement said pelacarsen did not produce a statistically significant reduction in that endpoint versus placebo. Specialist coverage by Cardiovascular Business likewise described the study as a primary-endpoint miss in patients with existing cardiovascular disease.
A lower biomarker did not establish a clinical benefit
The topline result draws a sharp boundary between a biological effect and a proven patient benefit. Novartis confirmed that pelacarsen lowered Lp(a), showing that the treatment engaged its intended target. But, based on the outcome announced so far, lowering Lp(a) with this drug did not demonstrate a reduction in the trial’s four-part cardiovascular endpoint across the full enrolled population.
That does not show that Lp(a) is irrelevant to cardiovascular risk, nor does it establish that every way of reducing Lp(a) will fail to prevent events. It is a result for one medicine, at the dose and duration used in this trial, in people with elevated Lp(a), established cardiovascular disease and contemporary background treatment. Other programs use different technologies and may study different patient groups.
Several companies are developing medicines aimed at Lp(a), including Amgen and Eli Lilly. Shares of Novartis fell 3% after the news, and shares in several companies pursuing competing Lp(a) medicines also declined, according to CNBC. Analysts cited by the network said the outcome weakens confidence in the broader hypothesis but does not settle whether the issue lies with pelacarsen, the trial setting or the strategy of Lp(a) lowering itself.
Critical data are still missing
The announced findings are preliminary topline results, not a complete trial report. Novartis has not publicly provided the numerical difference in cardiovascular events between the pelacarsen and placebo groups, the p-value, confidence intervals, event rates, follow-up duration, safety findings or analyses of patient subgroups. Those details could help clarify whether the result was close to the statistical threshold, whether any groups appeared to differ, and how to weigh the medicine’s risks and benefits.
Novartis said complete findings will be presented at a future medical congress. Until then, neither the magnitude of the outcome difference nor the reasons for the missed endpoint can be assessed independently. Clinical Trials Arena’s account similarly reported the endpoint miss while noting that full data are still to come.
The trial result does not change current treatment decisions; patients should discuss their cardiovascular risk, including whether Lp(a) testing is appropriate, with their clinician. For researchers and drug developers, the next evidence will be the full Lp(a)HORIZON dataset: whether any signal emerged in prespecified groups, how event patterns compared between the two arms, and whether future trials of other Lp(a)-lowering approaches can show an outcome benefit that pelacarsen did not demonstrate here.