Mark Delaney: Michael, okay, real talk — long week, but I have been genuinely unsettled since Tuesday and I need to just... say it out loud to someone.
Michael C. Vincent: Say it.
Mark Delaney: The Lp(a)HORIZON trial. Novartis and Ionis Pharmaceuticals run this massive Phase 3 cardiovascular outcomes trial — eight thousand, three hundred and twenty-three patients — and pelacarsen, the drug they're testing, does exactly what it's supposed to do. Lp(a) levels drop by up to eighty percent. And the patients still had the same rate of heart attacks and strokes as the placebo group.
Michael C. Vincent: Hold that thought — because I think we need to let that actually land. Eighty percent. That is not a nudge. That is biochemical demolition of the target. And the events happened anyway.
Mark Delaney: Which means either the drug failed — or the theory failed. And uh, I genuinely don't know which one is scarier.
Michael C. Vincent: Well. That is the exact question a cardiologist is sitting with right now, staring at that press release from Novartis.
Mark Delaney: And Dr. David Saxon already went on record calling it 'a landmark trial, whether positive or negative.' Like — that's not spin, that's someone trying to figure out what they just witnessed.
Michael C. Vincent: Whether positive or negative. A landmark either way. That is a scientist trying to make sense of a contradiction in real time.
Mark Delaney: But what's been eating at me since that landmark framing — the trial wasn't testing whether Lp(a) matters. It was testing whether you can show up forty years late and fix it. Like, imagine you've been slowly filling a bathtub for forty years. Lowering the water pressure now doesn't un-soak the floor.
Michael C. Vincent: And those forty years aren't arbitrary.
Mark Delaney: No, they're — okay, so Lp(a) levels are largely genetically determined. Like, baked in. The liver produces this protein, apolipoprotein(a), and pelacarsen's whole job is to block that production. Which it did. Crushed it. But the Mendelian randomization studies that built the whole case for Lp(a) as a risk factor? Those were capturing a lifetime of exposure. Every year, from birth, grinding away at the arteries. And every single patient in Lp(a)HORIZON already had established cardiovascular disease. Decades of damage already done before pelacarsen showed up.
Michael C. Vincent: So the science said Lp(a) causes disease over a lifetime. And the trial asked: can you stop it in the back half?
Mark Delaney: Exactly — and @afshineemrani on X, whose post got more engagement than basically anyone else covering this, put it almost word for word that way. Decades of genetic Lp(a) exposure may cause arterial damage that a few years of pharmacologic lowering in already-sick patients simply cannot reverse.
Michael C. Vincent: That is a devastating sentence if you're one of the roughly twenty percent of people walking around with elevated Lp(a) who don't even know it — because it doesn't show on a standard lipid panel.
Mark Delaney: Right — and now there's no approved targeted therapy for any of them. That's the gap this trial was supposed to close.
Michael C. Vincent: But wait — statins work in secondary prevention. Same patient population, established disease. Why should this be different?
Mark Delaney: Yeah, no — that's the question, right? That's the one nobody's fully answered yet.
Michael C. Vincent: That statin comparison — that's actually the thread worth pulling. Because statins work in secondary prevention by lowering LDL that is *still actively circulating*, still doing damage in real time. But every patient in Lp(a)HORIZON was already on aggressive guideline-directed therapy. Lipid-lowering, antihypertensive agents — already optimized. There was barely any residual biochemical risk left for pelacarsen to bite into.
Mark Delaney: Wait — so the background therapy was so good it crowded out the drug?
Michael C. Vincent: That is exactly what @nadig_cardio argued on X — verbatim position: the null result doesn't kill the Lp(a) hypothesis. It indicts the optimized background therapy context. You've already lowered the floor so much that adding pelacarsen has nowhere to stand.
Mark Delaney: Okay but — I mean, I hear that, and it's a real argument, but isn't that just... moving the goalposts? Like, Novartis and Ionis chose secondary prevention patients specifically because the risk was highest and the benefit would show fastest. You can't now say 'well, the patients were too well-treated.' That's the population you picked.
Michael C. Vincent: No, I'd hold that tension rather than resolve it. Because here's something we genuinely don't know yet — the trial enrolled patients with Lp(a) at seventy milligrams per deciliter or above. But there was a pre-specified subgroup requiring ninety or above. And those results have not been fully reported.
Mark Delaney: Huh — so there's a higher-threshold slice we haven't seen.
Michael C. Vincent: And until the full data publication lands, we don't even know if the MACE endpoint was underpowered, if follow-up was too short, or if the treatment effect is genuinely zero. Shreeram Aradhye — Novartis's own Chief Medical Officer — acknowledged the disappointment but framed it as advancing scientific understanding of the Lp(a)-cardiovascular relationship. That is a careful sentence from someone who cannot yet say which of those three explanations is true.
Mark Delaney: Picture a cardiologist right now — not in some meeting, just sitting with a patient chart open, someone who tested at ninety-five milligrams per deciliter six months ago and has been waiting on this trial. That doctor doesn't have the full publication. They have a press release and a null result.
Michael C. Vincent: And that gap — between the press release and the truth — is where the next part of this story lives. What the field actually does now, and what it means for anyone who just found out they're carrying this, is the question we haven't touched yet.
Mark Delaney: That patient with the chart — let me make it more specific. Someone found the Family Heart Foundation's trial listings. Searched 'Lp(a),' saw Lp(a)HORIZON, read that it was the first Phase 3 ever built to test this exact question. And they enrolled. Or they didn't enroll but they followed it. And now they're — I mean, what does their cardiologist actually say to them?
Michael C. Vincent: The cardiologist faces a fork. And neither road is comfortable.
Mark Delaney: Walk me through it.
Michael C. Vincent: One path: you say the trial tested the wrong moment in the disease. You invest in primary prevention — enroll people with the genetic burden who don't yet have heart disease. A trial like that takes a decade. And you have to convince an ethics board to put healthy people through years of injections for a maybe.
Mark Delaney: And the other path is — uh, actually, wait. Is the other path just giving up on lowering Lp(a) entirely?
Michael C. Vincent: The other path is entertaining that Lp(a) is a risk marker — not a causal target. That it flags danger without being the mechanism you pull. And if that's true, the investment case for the whole drug class collapses.
Mark Delaney: Which — okay, that's where olpasiran comes in, right? Different drug class from pelacarsen, still in development. If the hypothesis is still alive, olpasiran is the next real test of it. But it's testing the same theory that just failed its first pivotal Phase 3 ever.
Michael C. Vincent: The first pivotal Phase 3. Ever. That weight is worth sitting with.
Mark Delaney: And the person who found the Family Heart Foundation listings, who felt something when they saw this trial — they're not getting a clean answer. They're getting 'we don't know yet, and the next test takes ten years.' That's what a null result costs, beyond the stock price.
Michael C. Vincent: That's the image stuck with me. Tuesday morning, Mark says he's unsettled. Pelacarsen cut Lp(a) by up to eighty percent — did its one job, perfectly — and the cardiovascular events didn't move. Not a little. Not at all. A drug that works, and the disease doesn't notice.
Mark Delaney: Yeah — and I think, uh... maybe what the Lp(a)HORIZON trial actually did was answer the wrong version of the right question. Like, it's still the right question. We just asked it forty years too late in the disease.
Michael C. Vincent: The biology didn't cooperate with the timeline we gave it. And that's not nothing — that's a forty-year question that one trial could not answer. Olpasiran still out there. A whole primary prevention trial still to be designed, if anyone's willing to wait a decade for it.
Mark Delaney: One in five people, man. Carrying it. Most of them don't know.
Michael C. Vincent: And that is where it sits. Thank you for bringing this one.
