Novartis said its pelacarsen, the Ionis-partnered antisense therapy targeting lipoprotein(a) [Lp(a)], failed to reduce cardiovascular events in the Phase 3 HORIZON trial. The result is a setback for a class of drugs aimed at lowering a genetically determined heart-risk factor. In the study, pelacarsen lowered Lp(a) levels in earlier development, but did not translate into a reduction in major cardiovascular outcomes versus placebo. The failure raises fresh questions about whether Lp(a) lowering alone is sufficient to improve hard endpoints. The announcement comes as companies continue to invest in RNA-targeted cardiovascular strategies. For investors and trial designers, the negative readout may increase scrutiny on endpoint selection and effect size assumptions tied to biomarker changes. Clinically, the outcome adds urgency to alternative approaches for cardiometabolic risk reduction in patients predisposed to high Lp(a), including more stratified trial designs and exploration of combination mechanisms.