Heart-Drug Trial Cut Inflammation Markers by Up to 76%—But Did Not Prevent Heart Attacks

CHICAGO, November 7, 2026 — A drug that sharply reduced two blood markers of inflammation did not prevent heart attacks, strokes or cardiovascular deaths in a large late-stage trial. The finding is a reminder that changing a laboratory measurement is not the same as improving patients’ outcomes.

What the ZEUS trial found

The phase III ZEUS trial enrolled more than 6,300 adults with established atherosclerotic cardiovascular disease, chronic kidney disease and elevated inflammation. Participants received monthly injections of the experimental drug ziltivekimab or placebo alongside usual care. Detailed results were presented at the American Heart Association’s Scientific Sessions on November 7 and published simultaneously in the New England Journal of Medicine.

According to the American Heart Association’s trial summary, the drug lowered high-sensitivity C-reactive protein by 64% and interleukin-6 by 76% relative to placebo. Yet the combined endpoint of heart attack, stroke or cardiovascular death occurred in 561 treated patients versus 565 placebo recipients. The difference was not statistically significant. Serious infections were reported in 20% of the treated group compared with 18% of the placebo group.

Why a biological success was not a clinical success

Ziltivekimab blocks interleukin-6, a signaling molecule involved in inflammation. The blood-test changes suggest that the drug engaged its intended pathway. But the trial’s central question was whether patients would experience fewer serious cardiovascular events. On that measure, the intervention failed to demonstrate a benefit in this particularly high-risk population.

The results do not establish that inflammation is irrelevant to cardiovascular disease, nor that every drug acting on this pathway will fail. Participants already had both vascular disease and kidney disease; their advanced illness may have limited the benefit achievable through this specific approach. Those explanations remain hypotheses rather than demonstrated causes of the result.

A second warning from another cardiovascular drug

The findings arrive alongside disappointing results for pelacarsen, a separate experimental medicine developed by Novartis and Ionis to lower lipoprotein(a), an inherited cardiovascular risk factor. Novartis reported in September that its phase III Lp(a)HORIZON study did not meet its primary cardiovascular-outcome endpoint despite lowering Lp(a). Reuters’ November 7 reporting examines the two setbacks and researchers’ differing interpretations.

The studies target different mechanisms and populations; neither result should be used to infer that established preventive therapies, including appropriately prescribed cholesterol and blood-pressure medicines, are ineffective. Patients should not change treatment based on investigational-drug trial headlines.

What researchers need to answer next

Future studies may test other compounds, earlier stages of disease or different patient-selection criteria. For patients and clinicians, the key distinction remains between a promising biomarker response and proof that a treatment reduces outcomes that matter. The ZEUS trial supplied strong evidence for the former, but not the latter.

Image: illustrative anatomical heart model, photographed by Quilia via Unsplash; not a photograph of trial participants or procedures.

Sources: American Heart Association, November 7, 2026; Novartis, September 4, 2026; Reuters, November 7, 2026.

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