In March this year, the American College of Cardiology (ACC) and the American Heart Association (AHA), both globally recognised premier organisations in cardiovascular medicine, handed down their newest dyslipidemia guideline, and gave universal Lipoprotein(a) screening in every adult a ‘Class I’ recommendation — the strongest tier there is. The High-Sensitivity C-Reactive Protein (hsCRP) test got a lighter endorsement: checked selectively, alongside coronary calcium scoring, to sharpen risk estimates when they’re uncertain. These two long-debated biomarkers, were both freshly blessed by the field’s governing societies.

Then arrived the irony. On July 31, pharma major Novo Nordisk’s ziltivekimab — a drug built to block the inflammatory pathway behind elevated C-Reactive Protein (CRP) — fully hit its target in a Phase 3 clinical trial and still didn’t move the needle on heart attacks or strokes. Five weeks later, pelacarsenm, a drug that lowers high levels of Lp(a) failed the same way. Within six months of the guideline telling every clinician to start checking these numbers, the two flagship drugs built to act on them came up empty.

It’s a familiar shape for cardiology. Heart disease mortality fell almost every year through the back half of the last century — statins, blood pressure control, smoking cessation, better acute care — and that decline has visibly slowed this past decade, even as the drug arsenal has never been more sophisticated. LDL (’bad cholesterol’) is already driven remarkably low in anyone on a serious statin; medicine needed a new lever, and reached for the two candidates the guidelines had just endorsed. Neither has delivered yet.

What actually happened

On September 4, Novartis announced pelacarsen missed the primary endpoint of Lp(a)HORIZON, the first cardiovascular outcomes trial ever run for a drug built to lower lipoprotein(a). Pelacarsen is an antisense drug — a short, lab-made strand of genetic material injected monthly, designed to intercept the liver’s instructions for building Lp(a) before it’s ever made, rather than mopping up what’s already circulating. In 8,323 patients with established heart disease, it cut Lp(a) by roughly 80%. And yet, there was no reduction in heart attacks or stroke.

What we were taught

Lp(a) was drilled into me in medical school as one of the ‘unfair’ risk factors — a number you’re essentially born with, indifferent to diet or willpower, and loaded disproportionately onto South Asian patients, who as a population carry some of the highest mean Lp(a) levels of any group studied. It helped explain a pattern every cardiology rotation eventually shows you: South Asian patients with premature, multi-vessel disease and normal LDL numbers. That teaching isn’t wrong, and this trial doesn’t overturn it — Lp(a) is a real, heritable, biologically active risk factor. What it disputes is narrower: whether lowering it, this late and this fast, changes what happens next.

What Lp(a) actually is

Here’s the plain version of how a heart attack builds. LDL particles, commonly known as ‘bad cholesterol’ work their way into the artery wall and get stuck there. Once trapped, immune cells chemically alter them and swallow them up, ballooning into fat-filled ‘foam cells.’ Over years, those dying cells pile up into a fatty core, and the artery seals it off with a cap of scar-like tissue. When that cap eventually cracks or wears thin, a blood clot forms on top of it — that’s the heart attack.

Statins, ezetimibe, and the newer PCSK9-inhibitor injections all lower LDL through different mechanisms, but the trial data lines up the same way every time: about a 22% drop in heart attacks and strokes for every 39-point drop in LDL, no matter how you get there.

Lp(a) is an LDL particle with one extra piece stuck to it — a protein called apolipoprotein(a), built from the same molecular parts as the protein your body uses to break up blood clots. But it’s a decoy, not a copy: it fits into the same docking spots on a forming clot, without carrying the working part that actually gets activated into a clot-dissolving enzyme. So instead of helping to break clots down, it crowds out the real thing and makes clots a little harder to clear. That’s what makes Lp(a) different from LDL: it builds plaque the same way LDL does, but it also nudges the body toward clotting rather than away from it. And unlike LDL, your Lp(a) level is almost entirely set by your genes at birth — diet, exercise, and statins barely move it. 

Why did the trial fail?

A floor effect: Mean background LDL in the trial was 66 mg/dL as most patients were already on aggressive therapy. Whatever risk Lp(a) adds on top of that may be smaller than older, less-treated cohorts suggested, offering little room for an 80% reduction to matter.

Too late in the game: Every patient entered with 50-plus years of Lp(a) exposure already built into their arteries. Lowering the level for three or four years in someone’s sixties, after a cardiac event, may be too late to undo a lifetime of exposure the genetic data actually measured.

This isn’t cardiology’s first time at this wall. The CANTOS trial suggested a decade ago that quieting the immune system could work, independent of cholesterol reduction. Hitting the biomarkers still doesn’t seem to be enough: Lp(a) may just be writing the newest chapter of the same story.

Back to basics

The interventions with the deepest trial evidence are still the boring ones: eat well, move, don’t smoke, stay lean. LDL, blood pressure, glucose, and tobacco remain the pillars with decades of reproducible data behind them.

Lp(a) will likely still matter — as a flag for who needs those basics enforced hardest, and maybe eventually as a target that is treated decades earlier than this trial tried. But for now, the fanciest number on the panel failed its biggest test, and the oldest advice in medicine didn’t.

No antisense drug, no anti-inflammatory antibody, has found a way around the same wall. In Greek mythology, Icarus didn’t fall because he was foolish — he flew exactly as high as anyone reasonably could, and the sun turned out to be closer than he’d been told. Despite everything medicine can now measure, alter and silence, the quest for a healthy long life perhaps rests on the same principles it has rested on for centuries: eat well, move well, sleep well.

(Dr. Dinesh Arab is director, interventional and structural cardiology, AdventHealth Daytona Beach and clinical assistant professor of medicine, Florida State University. dinarab@yahoo.com)