Novo Nordisk Falls Over 10% in Largest Single-Day Drop in Nearly Five Months After Announcing Heart Drug Trial Failure

TradingKey - On July 31, ET, Novo Nordisk ( NVO) once fell over 10%, marking its largest single-day drop since February 23, 2026. As of press time, it was still down 8.84% at $47.05.

Reportedly, Novo Nordisk announced on Friday that its highly anticipated investigational heart drug ziltivekimab failed to meet the primary endpoint in a large late-stage clinical trial.

Novo Nordisk stock price chart, Source: TradingView

The trial, named "Zeus", aimed to evaluate whether the once-monthly injection of the IL-6 inhibitor ziltivekimab, on top of standard care, could further reduce the risk of major adverse cardiovascular events (MACE) compared to a placebo in specific patient populations. MACE is defined as cardiovascular death, non-fatal myocardial infarction, or non-fatal stroke, and Jefferies estimates this market size to be worth over $10 billion annually.

Analysts had generally expected the drug to show at least some efficacy. Jefferies noted before the results were announced that the study would need to see at least a 20% risk reduction to support widespread use.

Goldman Sachs analysts noted before the results were released that if the trial succeeded, ziltivekimab could have been the core of Novo Nordisk's effort to build a cardiovascular disease franchise, reducing the company's high reliance on Ozempic and Wegovy.

Martin Holst Lange, Chief Scientific Officer at Novo Nordisk, said: "While ziltivekimab did not achieve the major adverse cardiovascular event (MACE) benefit we expected, this does not change our strategic commitment to cardiovascular disease."

However, analysts at Jefferies and Citi both stated that given ziltivekimab's small share in Novo Nordisk's overall portfolio, the stock price volatility seemed excessive.

Jefferies pointed out: "This result is strategically negative because it deprives Novo Nordisk of a relatively reliable growth opportunity in the non-obesity field, and once again highlights the company's commercial execution in obesity as well as its current reliance on external innovation to drive growth."