Lepodisiran: The Once-a-Year Shot Aimed at Lp(a) — Inside Lilly's ACCLAIM-Lp(a) Trial (August 7, 2026)
Table of Contents
The risk factor genetics deal you at birth
Lipoprotein(a) — written Lp(a) and spoken 'L-P-little-a' — is one of the most important cardiovascular risk factors most people have never heard of. Roughly one in five people worldwide inherit high levels, and it is a causal driver of heart attack, stroke, peripheral artery disease, and calcific aortic valve stenosis. The frustrating part is that your Lp(a) is set almost entirely by your genes. It barely moves with diet or exercise, and the two workhorses of modern cholesterol care — statins and PCSK9 inhibitors — leave it essentially untouched. There is no approved therapy that lowers it specifically, which is why a wave of gene-silencing drugs is now racing to fill that gap.
What lepodisiran is
Lepodisiran (LY3819469) is an investigational injectable from Eli Lilly. It is not a peptide or an antibody but a small interfering RNA — an siRNA — a short, double-stranded piece of genetic material that works through the RNA-interference pathway your cells already use to regulate their own genes. A sugar tag called GalNAc acts as a homing beacon that delivers the drug to liver cells. Once inside, lepodisiran hands its guide strand to the cell's RISC machinery (the RNA-induced silencing complex), which then finds and chops up the messenger RNA for apolipoprotein(a), the protein that defines the Lp(a) particle. With that mRNA destroyed, the liver makes far less apo(a) and assembles far fewer Lp(a) particles.
The differentiator: how long one shot lasts
Every drug in this class exploits the fact that RISC is catalytic — it keeps cutting apo(a) messages long after a single dose. But lepodisiran is engineered specifically for duration. Its chemistry, including a stabilizing tetraloop that joins the two RNA strands, gives it an unusually long life inside liver cells. In Phase 2, a single injection kept Lp(a) around 91% below baseline at roughly one year and still about 74% below baseline at 1.5 years. That is the whole pitch: not a daily pill or even a quarterly shot, but potentially a once- or twice-a-year injection for a lifelong, inherited risk.
How well does it lower Lp(a)?
Strikingly well. In the Phase 2 ALPACA trial — 320 adults with elevated Lp(a) given 16, 96, or 400 mg — the top 400 mg dose lowered Lp(a) by 93.9% (placebo-adjusted, averaged over days 60 to 180), meeting the primary endpoint, while the 96 mg and 16 mg doses produced 75.2% and 40.8% reductions. There were no serious drug-related adverse events. The results were presented at the American College of Cardiology 2025 Scientific Sessions and published in the New England Journal of Medicine. As with the rest of this class, the open question was never whether lepodisiran lowers Lp(a) — it clearly, dramatically does — but whether that lowering actually prevents heart attacks and strokes.
ACCLAIM-Lp(a): the experiment that matters
That question is what the Phase 3 ACCLAIM-Lp(a) trial (NCT06292013) was built to answer. It enrolled about 12,500 patients, randomized 1:1 to lepodisiran or placebo on top of standard care, and tests whether lowering Lp(a) reduces major adverse cardiovascular events. Dosing is deliberately infrequent — the first three subcutaneous injections are six months apart, then every 12 months. What sets ACCLAIM apart from the other big Lp(a) trials is who it enrolls: it is the first Lp(a)-lowering outcomes trial to include primary-prevention patients — people who are at risk but have not yet had a cardiovascular event — alongside those with established disease. Because it is event-driven, it runs until enough cardiovascular events accrue, with completion expected around 2029.
Where lepodisiran sits in the class
Lepodisiran is one of a tight cluster of Lp(a)-lowering drugs chasing the same finish line. The antisense oligonucleotide pelacarsen (Ionis/Novartis) is furthest along, with its Lp(a)HORIZON outcomes trial reading out in 2026; Amgen's olpasiran, an every-12-weeks siRNA, has its OCEAN(a)-Outcomes readout expected around December 2026; and Silence Therapeutics' zerlasiran is a third siRNA in the mix. Lepodisiran's edge is duration and reach — the longest dosing interval and the only trial extending into primary prevention — but its outcomes data arrive later, around 2029. All of them rest on the same unproven premise: that lowering Lp(a) will translate into fewer cardiovascular events.
The bottom line
Lepodisiran is an investigational, long-duration siRNA from Eli Lilly that lowers lipoprotein(a) by nearly 94% by silencing the apolipoprotein(a) gene in the liver — with a single shot lasting a year or more. It is not approved anywhere, and it is a prescription clinical-stage medicine, not a supplement or research chemical; anything sold under the names 'lepodisiran' or 'LY3819469' by a vendor is unverified. Its Phase 3 ACCLAIM-Lp(a) trial is the first Lp(a) outcomes study to include people who have not yet had a cardiovascular event, and while its answer won't arrive until around 2029, it could ultimately reach the widest population of the whole Lp(a)-lowering class — which also includes pelacarsen, olpasiran, and zerlasiran.
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Citations
- [1] Nissen SE et al. — Lepodisiran, A Long-Duration Small Interfering RNA Targeting Lipoprotein(a) (ALPACA Phase 2), New England Journal of Medicine (2025) Source
- [2] ACCLAIM-Lp(a) — Effect of Lepodisiran on Major Adverse Cardiovascular Events (ClinicalTrials.gov NCT06292013) Source
- [3] Lilly's lepodisiran reduced Lp(a) by nearly 94% at the highest tested dose — Eli Lilly and Company (ACC 2025) Source
- [4] Lipoprotein(a): An Independent Risk Factor for CV Disease — American College of Cardiology Source
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