Novo Nordisk Stock Tumbles Amid Eli Lilly's Positive Weight-Loss Drug Trial Results

Novo Nordisk's stock fell 2% on Tuesday after rival Eli Lilly reported positive top-line results for its GLP-1 weight-loss treatment, Orforglipron. The drug met all primary and key secondary endpoints, producing a 10.5% average weight loss and lowering blood sugar levels. Orforglipron is delivered in pill form, a more convenient option than Novo Nordisk's injected Wegovy and Eli Lilly's Zepbound. The mounting competition in the obesity segment may challenge Novo Nordisk's position in the market.

Novo Nordisk's stock fell 2% on Tuesday following Eli Lilly's positive top-line results for its GLP-1 weight-loss treatment, orforglipron. The drug met all primary and key secondary endpoints, achieving a 10.5% average weight loss and reducing blood sugar levels. Orforglipron, delivered in pill form, offers a more convenient option compared to Novo Nordisk's injected Wegovy and Eli Lilly's Zepbound. The mounting competition in the obesity segment may challenge Novo Nordisk's position in the market.

The late-stage trial results, announced by Eli Lilly, demonstrated that orforglipron was safe and effective for people with overweight and obesity, as well as type 2 diabetes. On average, study participants lost 22.9 pounds (10.5% of their weight) on the highest dose of the medication (36 milligrams) after using it once a day for 72 weeks. The pill also lowered A1C, a measurement of average glucose levels in the blood, by an average of 1.8%. The adverse events reported were generally mild to moderate, with upset stomach being the most commonly reported side effect [2].

The convenience of orforglipron's pill form is a significant advantage over injectable treatments. Unlike Novo Nordisk's Rybelsus, which requires strict dietary restrictions and administration on an empty stomach, orforglipron can be taken with food or water. This convenience is a critical factor in a market where patient adherence is notoriously low—fewer than 30% of patients remain on anti-obesity medications after one year [1].

Eli Lilly's manufacturing capabilities provide a structural advantage. The company's acquisition of Catalent in 2024 for $16.5 billion has expanded its production capacity to meet global demand. Analysts estimate that orforglipron's production costs could be 30–50% lower than injectables, enabling a pricing strategy that undercuts Novo Nordisk's Rybelsus and Wegovy [1].

The obesity drug market is a duopoly dominated by Novo Nordisk and Eli Lilly, but the landscape is evolving. Orforglipron's lower cost and ease of use could disrupt this dynamic, particularly in the U.S., where Medicare and Medicaid expansions are expected to cover obesity treatments for non-diabetic patients by 2026 [1].

For investors, the risks are manageable. Orforglipron's slightly lower efficacy compared to Novo's oral semaglutide is offset by its convenience and cost. Additionally, Lilly's diversified portfolio—Zepbound, Mounjaro, and a robust diabetes pipeline—provides downside protection. Analysts at Leerink Partners and GlobalData have upgraded Lilly's stock to “Outperform,” citing its leadership in the obesity space and potential for $14.1 billion in orforglipron revenue by 2031 [1].

References:
[1] https://www.ainvest.com/news/eli-lilly-orforglipron-game-changer-oral-glp-1-therapy-hold-play-2026-growth-2508/
[2] https://www.cnn.com/2025/08/26/health/glp-1-pill-eli-lilly