Earlier this year, the ACC and AHA made a major change to cholesterol screening: the 2026 guideline says every adult should have their lipoprotein(a), or Lp(a), checked at least once in their lifetime. That pushed a little-known marker into the mainstream. But it left one big question: if we lower Lp(a) on purpose, do we actually prevent heart attacks, strokes, and deaths?
On September 4, the first large trial built to answer that reported early results, and it fell short. Novartis announced that its drug pelacarsen lowered Lp(a) in more than 8,000 patients with heart disease but did not meaningfully reduce heart attacks, strokes, or cardiovascular deaths compared with placebo. These are early, company-reported results; the full data hasn’t been published yet.
This matters beyond one drug. It was the first real test of one of the hottest ideas in heart medicine, and it raises the bar for everyone else chasing this target.
What Pelacarsen Was Supposed to Prove
Lp(a) is mostly inherited. Genes set more than 90% of your level, and diet and exercise barely change it. About 1 in 5 people have high levels, and higher levels mean higher heart risk. The 2026 guideline now flags an Lp(a) of 125 nmol/L (50 mg/dL) or above as a risk booster.
What’s still missing is any FDA-approved drug proven to lower the heart risk that comes with high Lp(a). Pelacarsen, an injection that switches off the body’s production of the Lp(a) particle, was meant to be that drug. In early studies, the strongest doses cut Lp(a) by about 80%. But the once-monthly dose used in this big trial lowers it by only about half, a detail that matters when a trial comes up empty.
The Trial’s First Big Answer
The trial, called Lp(a)HORIZON, enrolled 8,323 patients with known heart disease and high Lp(a), giving them either pelacarsen once a month or placebo, on top of all their usual, proven heart medicines. The goal was to see whether lowering Lp(a) could cut the extra risk that remains even after standard treatment is optimized. It measured cardiovascular death, heart attack, stroke, and urgent heart procedures. Pelacarsen lowered Lp(a), but, per the early results, it did not reduce those events.
The Number Moved. The Outcome Didn’t.
That’s the key lesson: the lab number changed, but patients didn’t do better. Medicine has seen this before: a marker can be tightly linked to disease, yet a drug that changes it may not help. This doesn’t mean Lp(a) is meaningless; strong genetic and population evidence still ties it to heart disease. But real trials ask the tougher question: not “did the number move?” but “did the patient benefit?” Pelacarsen answered the first, not the second.
This Doesn’t Mean Lp(a) Is Dead
It’s too early to say lowering Lp(a) can’t work. Only early results are out, and the full picture, including how much Lp(a) actually dropped, is still coming. And that matters, because this dose only cut Lp(a) by about half rather than the ~80% seen with the strongest doses. Genetic studies hint that a much larger drop may be needed to move the needle on heart disease. So a bigger reduction, higher starting levels, or starting treatment earlier, before decades of damage add up, could all still make a difference. We don’t know yet, but these questions just got a lot more important.
Now Watch Amgen and Lilly
Pelacarsen was just the first to the finish line. Amgen’s olpasiran lowers Lp(a) by roughly 90–97% and is in a large ongoing outcomes trial. Eli Lilly is testing lepodisiran, another injection, and muvalaplin, a pill. This next wave can test whether deeper lowering, higher starting levels, or earlier treatment finally delivers a benefit. HORIZON didn’t end the Lp(a) story; it raised the bar.
Why This Matters for Pharmacists
Heart medicine is in an odd spot: guidelines say to check Lp(a) more often, yet the first drug aimed at it just failed. Pharmacists will meet more patients who know their Lp(a) is high but have no drug that targets it. Those conversations need care.
A high Lp(a) still matters, as a strong reason to attack the risks we can control: LDL cholesterol, blood pressure, diabetes, smoking, weight, activity, and taking medicines as prescribed. The 2026 guideline goes one step further: for patients with heart disease and high Lp(a) who aren’t at their cholesterol goal on the highest statin dose they tolerate, it recommends adding a PCSK9 inhibitor. That’s a concrete step a pharmacist can flag today. The real value isn’t waiting for a future Lp(a) drug; it’s making sure the rest of the patient’s heart risk is handled as well as possible right now.
The Bigger Lesson
New tests and markers keep arriving faster than proof that changing them helps patients. HORIZON is a reminder to move past “Did the drug change the number?” toward “Did it change the patient’s life?” That’s the standard every Lp(a) drug now has to meet.
Your Action This Week
Start checking Lp(a) when you review heart patients; the guideline’s once-in-a-lifetime recommendation means it’s about to become routine. Pick one patient with early heart disease, a strong family history, or repeat events and ask: Do we know their Lp(a)? If not, there’s now a guideline-backed reason to raise it.
If it’s high, don’t wait for a new drug. Check the LDL, and if they’re not at goal on a maximally tolerated statin, ask whether a PCSK9 inhibitor is warranted. Review blood pressure, diabetes, and adherence, and tackle smoking and other risks. Pelacarsen may have failed its first big test, but the heart risk tied to high Lp(a) didn’t disappear with it.
References
• Wiggins et al. J Am Coll Cardiol. 2026 — 2026 ACC/AHA Dyslipidemia Guideline (once-in-a-lifetime Lp(a) testing; ≥125 nmol/L or ≥50 mg/dL as risk-enhancing; Class 1 PCSK9 inhibitor recommendation).
• Parhofer et al. Eur Heart J. 2026 — Pelacarsen trial data (mechanism and Lp(a) lowering).
Nordestgaard & Langsted. Lancet. 2024 — Lp(a) biology, prevalence, and cardiovascular risk association.
• Wu et al. Pharmacol Res. 2026 — Network meta-analysis of Lp(a)-lowering therapies (olpasiran and comparative reduction data).
• Rader DJ. N Engl J Med. 2025 — Review of Lp(a) as a therapeutic target.
• Lamina et al. JAMA Cardiol. 2019 — Mendelian randomization estimate of the Lp(a) reduction likely needed to lower coronary risk.
