Novartis cuts Lp(a) by 78% with no clinical benefit, prompting Merck KGaA to drop its programme
Key Facts
Merck KGaA has decided not to pursue its research programme targeting lipoprotein(a), known as Lp(a), after Novartis' pelacarsen trial failed to reduce cardiovascular events, the company's healthcare chief Danny Bar-Zohar said during its third-quarter earnings call. “The Lp(a) project is not something we will continue working on from our point of view,” Bar-Zohar said. The decision takes Merck KGaA out of development of the programme as Lp(a)-lowering drugs face a difficult clinical test. But the result of one trial does not settle whether lowering the protein can reduce heart risk. Nor does it show that the entire treatment class is ineffective.
Novartis' Lp(a)HORIZON trial failed to meet its primary endpoint of reducing the risk of a group of cardiovascular events compared with placebo, the company said on 4 September. The trial included 8,323 patients with elevated Lp(a) levels and existing cardiovascular disease. Detailed results showed the primary endpoint occurred in 12.3% of patients who received pelacarsen, compared with 12.1% in the placebo group. Median follow-up was 57 months, or nearly five years. The results therefore showed no difference in the primary clinical outcome between the groups, despite the substantial change in protein levels.
Pelacarsen reduced Lp(a) levels by an average of 78% during the trial, but the timing of major cardiovascular events did not change, according to the American Heart Association. The result highlights the gap between an effect on a biomarker and the ability to show a patient benefit in clinical outcomes. “One trial does not provide definitive evidence that lowering lipoprotein(a) is not beneficial as a strategy to reduce cardiovascular risk,” said Steven Nissen, the study's lead author. The neutral results remain useful for research, he added, according to the Cleveland Clinic. The Lp(a)HORIZON result alone is therefore not enough to close the case on this treatment approach.
Novartis said it would stop developing pelacarsen for atherosclerotic coronary artery disease but would continue one trial targeting calcific aortic stenosis, according to a report by Bloomberg via SWI swissinfo.ch. That means the company's decision does not halt every study of the drug, although its use for coronary artery disease will be discontinued. When Novartis announced the trial result, it said elevated Lp(a) affects about one in five people worldwide. It added at the time that there was no approved treatment specifically targeting the elevation. That unmet medical need remains in the background of the research race, despite the disappointment of the primary trial.
Detailed results were presented in a late-breaking science session at the American Heart Association's 2026 meetings in Chicago and published simultaneously in the New England Journal of Medicine. Novartis' initial announcement that the trial had missed its primary endpoint came on 4 September. In the context of Lp(a) research, a June 2026 filing by Merck & Co with the U.S. Securities and Exchange Commission said its investigational drug MK-7262 (HRS-5346) is an oral inhibitor, with development and commercialisation rights outside Greater China secured under a licensing agreement with Hengrui Pharma. Merck & Co's pipeline page describes the drug as an oral Lp(a) inhibitor in development. That company is separate from Merck KGaA, whose executive announced the halt to the Silence programme.
EL7 data showed Merck KGaA shares closed at $33.84 on 11 November 2026, while Novartis shares closed at $160.32 on the same day. These prices predate the news on 12 November and represent the previous session's closes; they do not measure the market's reaction to the announcement that Merck KGaA would stop its programme. The available evidence did not include a later price or share movement linked to the decision. The comparison between the two stocks therefore describes only the 11 November close. The next stage in the trials comes with the continuation of the pelacarsen trial for calcific aortic stenosis, while Novartis has stopped its development for atherosclerotic coronary artery disease.