DrugSalesDB Research Note
The New King of Pharma: How Mounjaro Unseated Keytruda in 2026
Mounjaro's rise to the top of the quarterly drug sales leaderboard was not a one-quarter surprise. It was a visible inflection point building in the data as GLP-1 revenue momentum reshaped the high end of pharma.
Investor takeaway: In the latest DrugSalesDB quarterly view, Eli Lilly's Mounjaro overtook Merck's Keytruda, posting about $8.7B in quarterly product sales. The signal was visible well before the rank changed: Mounjaro's revenue curve was compounding while Keytruda looked like a mature mega-franchise.
To casual observers, the ranking flip can look like a sudden headline. In a quarter-by-quarter sales view, it looks more like a slow-motion handoff. Keytruda started the period as the clear number one product. Mounjaro began as a fast-growing top-10 product and then climbed with unusual speed.
The investor takeaway: spot the inflection point
In 2024 Q2, Keytruda was still the obvious leader, with quarterly sales of about $7.3B in this dataset. Mounjaro was already large, but ranked sixth at about $3.1B. By 2026 Q1, Mounjaro had reached about $8.7B and moved to number one, while Keytruda was about $7.9B and ranked second.
The important signal was not only the final rank. It was the velocity. A mature blockbuster can still grow and remain enormously valuable, but a product with a near-vertical sales curve can rewrite the leaderboard quickly. That is the kind of product-level signal investors can miss if they only scan annual company revenue.
Immuno-oncology vs. metabolic repair
The top of the global pharma stack now shows two very different models of 21st-century medicine, both delivering huge clinical and commercial impact.
Keytruda, Merck's anti-PD-1 cancer immunotherapy, is the classic modern oncology blockbuster. It helps the immune system recognize and attack tumors, and it has become a foundation therapy across major cancer indications.
Mounjaro, Lilly's dual GIP/GLP-1 receptor agonist, is a different kind of mega-franchise. It targets metabolic disease at enormous population scale. The commercial ceiling is shaped by diabetes, obesity, cardiovascular risk, and the broader medical consequences of metabolic dysfunction.
That contrast matters. Keytruda's brilliance is deep oncology expansion. Mounjaro's force is epidemiological scale.
The Q1 2026 revenue leaderboard
A rank-based view exposes a simple reality: flat performance can mean falling behind. Mature oncology workhorses like Opdivo and major virology franchises like Biktarvy still generate large revenue, yet they slid down the relative ranking as metabolic and immunology assets re-centered the market's gravity.
The forward outlook
The commercial trajectory of these blockbusters confirms that global healthcare capital is moving. For biotech investors and equity analysts, product-level revenue velocity is one of the cleaner signals for mapping therapeutic-area momentum, testing franchise durability, and spotting which products have the runway to become the next mega-blockbuster.
That is the purpose of DrugSalesDB: turn scattered company-reported product sales into a comparable research layer, so the next ranking shift is easier to see while it is still forming.
Common questions
What is the best-selling drug in the world?
In the latest quarter shown here, Mounjaro ranked first in the DrugSalesDB view, followed by Keytruda and Ozempic.
Which drugs moved up the most?
Mounjaro was the biggest move at the top of the chart, rising from sixth place to first. Zepbound also moved rapidly, becoming a top-tier product in the visible ranking.
Is this the same as IQVIA-style prescription data?
No. DrugSalesDB is built from company-reported product sales and investor materials. It is revenue data, not claims data, prescription count, unit volume, or patient count.
Explore the full database
The DrugSalesDB deliverable includes an Excel/CSV product-sales database and an offline interactive HTML dashboard for comparing drugs across companies, quarters, and therapeutic areas.