THE WHAT? Eli Lilly’s diabetes treatment Mounjaro has overtaken Merck’s cancer therapy Keytruda to become the world’s top-selling pharmaceutical product.
THE DETAILS Mounjaro generated US$8.7 billion in first-quarter 2026 sales, surpassing Keytruda’s US$7.9 billion revenue during the same period. Keytruda had held the position as the world’s best-selling drug since early 2023. Lilly’s performance becomes even stronger when combined with obesity drug Zepbound, which uses the same active ingredient, tirzepatide. Together, the two products generated US$36.5 billion in 2025 sales, exceeding Keytruda’s annual revenue of US$31.6 billion. Analysts said demand for obesity and diabetes treatments continues to accelerate globally due to the effectiveness and safety profile of GLP-1 medicines. Meanwhile, Merck is preparing for Keytruda’s patent expiry in 2028, which is expected to intensify pressure on the company’s oncology business.
THE WHY? The shift highlights the rapid rise of obesity and diabetes treatments as one of the pharmaceutical industry’s most commercially significant categories, reshaping the global healthcare and wellness market.
Source: Bloomberg
