Wegovy cuts cardiovascular event risk by over half vs tirzepatide—real-world data raises Novo Nordisk lead

How does Wegovy lower cardiovascular event risk by over 50% compared to tirzepatide in real-world patients with obesity and CVD?

Novo Nordisk (NYSE: NVO) unveiled real-world evidence showing that its blockbuster obesity drug Wegovy® (semaglutide 2.4 mg) significantly outperforms tirzepatide in reducing the risk of major cardiovascular events in people with overweight or obesity and established cardiovascular disease (CVD). The STEER study, presented at the European Society of Cardiology (ESC) Congress 2025 in Madrid, found Wegovy lowered the risk of heart attack, stroke, or death from any cause by 57% compared to tirzepatide in patients who remained consistently on treatment.

The results are a boost for Novo Nordisk’s case that semaglutide offers cardiovascular benefits beyond weight loss—benefits that cannot be assumed to extend to other GLP-1 or GIP/GLP-1 receptor agonists like Eli Lilly’s tirzepatide (marketed as Mounjaro or Zepbound). While tirzepatide is regarded for its dual action on GLP-1 and GIP receptors and strong weight-loss efficacy, the STEER data suggests a clinically meaningful divergence when it comes to cardiovascular protection.

What specific risk reductions were observed with Wegovy versus tirzepatide in the STEER real-world study?

In the primary sensitivity analysis—evaluating patients who did not have treatment gaps longer than 30 days—only 15 cardiovascular events (0.1%) were observed in the Wegovy group versus 39 (0.4%) in the tirzepatide group. This corresponds to a 57% relative risk reduction over an average follow-up of 3.8 months for Wegovy versus 4.3 months for tirzepatide.

In the broader patient population—regardless of treatment gaps—Wegovy users still saw a 29% risk reduction: 56 cardiovascular events (0.5%) versus 83 (0.8%) in the tirzepatide group, with follow-up durations of 8.3 months and 8.6 months, respectively. Events tracked included heart attack, stroke, and death from any cause.

These results suggest that semaglutide’s heart-protective effects persist across patient adherence levels, although the benefit was more pronounced in those with high treatment continuity.

Why do analysts say the CV benefits may be specific to semaglutide rather than a GLP-1 class effect?

Institutional analysts following the obesity and diabetes drug market interpreted the findings as a key differentiator for Novo Nordisk, particularly as payer organizations and cardiology guidelines begin factoring real-world data into treatment recommendations. The STEER study adds to a growing body of evidence suggesting that semaglutide’s cardiovascular benefits stem from the molecule itself, rather than from the broader GLP-1 or GIP/GLP-1 drug class.

Anna Windle, Senior Vice President of Clinical Development, Medical and Regulatory Affairs at Novo Nordisk, said the study reinforces the unique benefits of semaglutide outside of weight management, particularly for patients already living with cardiovascular disease. She emphasized the role of real-world studies in validating outcomes beyond controlled clinical environments.

This differentiation could be critical in shaping future drug labeling, payer coverage decisions, and physician prescribing behavior—especially among non-diabetic patients who have historically lacked treatment options offering both weight loss and cardiovascular protection.

How does the STEER study fit into the broader clinical landscape around semaglutide and GLP-1s?

The real-world STEER study complements prior randomized trial data from SELECT, which showed that Wegovy lowered the risk of major cardiovascular events in overweight or obese patients without diabetes. Unlike SELECT, which was placebo-controlled, STEER provides an active comparator—tirzepatide—thus offering more actionable comparisons in the context of treatment decisions.

STEER drew its data from the U.S.-based Komodo Research database, focusing on adults aged 45 years and older who began either Wegovy or tirzepatide after May 13, 2022. Propensity score matching was used to ensure patient comparability across the two cohorts, each consisting of 10,625 individuals.

Outcome measures included both revised and non-revised three-point and five-point MACE (major adverse cardiovascular events), such as myocardial infarction, stroke, hospitalization for heart failure, coronary revascularization, and death.

While observational studies like STEER cannot definitively establish causality, they are increasingly relied upon by regulators, insurers, and clinicians as meaningful evidence, especially when randomized controlled trials are unavailable or impractical.

What’s the latest sentiment from institutional investors and analysts tracking obesity and CVD drugs?

Investor sentiment has been decisively positive. Shares of Novo Nordisk (NVO) rose nearly 3% following the announcement, lifting Denmark’s OMXC20 index and adding fuel to analyst projections of sustained market leadership. Financial analysts noted that the cardiovascular benefit, combined with prior weight-loss efficacy data, may further insulate semaglutide from upcoming biosimilar threats or payer-driven cost pressure.

In contrast, sentiment toward Eli Lilly (NYSE: LLY) has remained cautious. While Lilly’s tirzepatide franchise has demonstrated strong commercial uptake—particularly among diabetic patients—its relative underperformance in cardiovascular protection could narrow its appeal in non-diabetic patient segments. Analysts flagged that Mounjaro’s recent 8% reduction in cardiovascular events (vs Trulicity) lacks the clinical impact to compete with Wegovy’s 57% relative risk reduction in STEER.

Market watchers expect greater divergence in payer and guideline support, particularly in countries or systems where cardiovascular risk reduction is prioritized alongside weight loss.

What should patients and clinicians know about safety and prescribing considerations for Wegovy?

While Wegovy has now demonstrated clear cardiovascular benefits in both clinical trials and real-world evidence, it still carries a boxed warning for potential thyroid tumors. It is contraindicated in individuals with a personal or family history of medullary thyroid carcinoma or multiple endocrine neoplasia syndrome type 2.

Common side effects include nausea, vomiting, diarrhea, stomach pain, headache, and fatigue. Novo Nordisk has reiterated that Wegovy should not be used alongside other semaglutide-containing products or GLP-1 receptor agonists.

The U.S. FDA-approved labeling includes indications for reducing cardiovascular risk in adults with known heart disease and obesity, as well as weight management for individuals aged 12 and older with obesity or adults with overweight and weight-related health problems.

How is obesity shaping long-term cardiovascular health strategies?

Obesity remains a critical risk factor for cardiovascular morbidity and mortality worldwide. According to the World Heart Federation, two in three obesity-related deaths are linked to CVD. While global heart disease mortality has declined in recent decades, obesity-related cardiac deaths have surged—posing a challenge for both public health systems and pharmaceutical innovators.

In this context, Wegovy’s dual benefits in weight reduction and cardiovascular risk mitigation are seen as game-changing by clinicians and analysts alike. As global obesity rates climb, treatments that address both metabolic and cardiovascular endpoints may increasingly become the standard of care.