Health · Medical Research · 58 mins ago
Pelacarsen lowers a heart-risk marker but does not prevent complications
A trial of pelacarsen found no reduction in major heart complications among people with existing heart disease and high levels of Lp(a), a blood particle linked to cardiovascular risk.
The study involved 8,350 adults, who received either the drug or a placebo and were followed for about five years.
Pelacarsen lowered Lp(a) levels by about 78%, but that change did not prevent heart-related deaths, heart attacks, strokes or urgent procedures to unblock blood vessels.
High Lp(a) is often inherited, and elevated levels affect about one in five people worldwide.
The results challenge hopes that lowering Lp(a) would prevent heart attacks and strokes, though they do not establish why the treatment failed.
Novartis, which sponsored the study, has abandoned pelacarsen, while researchers say it remains unclear whether Lp(a) itself causes harm or whether treatment would need to start earlier or last longer.
Pelacarsen substantially lowered lipoprotein(a), or Lp(a), but did not reduce major cardiovascular complications in a large trial.
The Phase 3 HORIZON trial found no difference in heart attacks, strokes, urgent coronary procedures or deaths between people taking the drug and those given a placebo.
The 8,350 participants had previously experienced a cardiovascular event and had high Lp(a) levels.
Researchers presented detailed findings at the American Heart Association’s scientific sessions in Chicago and published them in medical journals.
The result raises questions about whether lowering Lp(a) can prevent cardiovascular events and how the particle contributes to heart disease.
- Who
- Novartis-funded researchers, led by Steven Nissen, studied pelacarsen in 8,350 adults with prior cardiovascular events and high Lp(a).
- What
- The drug lowered Lp(a) but did not prevent major cardiovascular complications compared with a placebo.
- When
- Detailed findings were presented on Saturday, November 7, 2026.
- Where
- The findings were presented at the American Heart Association’s scientific sessions in Chicago.
- Why
- The study tested whether lowering Lp(a) could reduce cardiovascular risk. The sources do not state why the drug failed to improve outcomes.
This story does not have two clearly opposing sides.
Top-line results showed pelacarsen lowered Lp(a) but failed to lower serious cardiovascular outcomes.
Novartis announced that the study had not met its goals, without releasing details.
Researchers presented detailed HORIZON trial findings at the American Heart Association’s scientific sessions in Chicago and published them in medical journals.
- Trial participants
- 8,350 adults with prior cardiovascular events and high Lp(a)
- Trial duration
- Participants were followed for almost five years
- Lp(a) reduction
- About 78% in the NPR report
- Trial comparison
- Pelacarsen versus placebo
- Measured outcomes
- Heart attacks, strokes, urgent coronary procedures and deaths
4 sources
#AHA26: The similar, surprising Novo and Novartis heart drug failures spelled out
A promising drug for an inherited heart risk flops, stunning doctors
STAT+: Failure of Novartis Lp(a) drug raises questions about cardiovascular strategy
A promising new medicine against heart disease fails unexpectedly
What people are saying
It wasn’t a near miss. It just didn’t have an effect on outcomes, and I don’t think virtually anybody’s prepared to hear that
I was shocked. I had high hopes for success.
Progress in science depends on pursuing challenging questions and studies [like the pelacarsen study] play a crucial role in moving the field forward, even if the results are not what we had hoped for
I think it's a big deal because the expectation was so high that this would end up being positive.