$36.5 billion new "King of Drugs" born: The era dominated by metabolic diseases begins

In 2025, the global “King of Drugs” scepter completed a milestone handover. Recently, major pharmaceutical companies worldwide released their 2025 financial reports, with Eli Lilly’s Tirzepatide topping sales at $36.507 billion, followed closely by Novo Nordisk’s Semaglutide at $36.1 billion. Merck’s Mounjaro, which had held the crown for two consecutive years, dropped to third place. The two GLP-1 drugs swept the top two spots, marking a power shift in the era of treatment—from tumor immunology dominance to the rise of metabolic disease therapies. This shift fundamentally reflects the market potential differences across various treatment fields, heralding a historic restructuring of the global pharmaceutical industry landscape.

1

Decisive Battle in Q4 2025: The New “King of Drugs” Achieves a Comeback

Eli Lilly’s dual-target GLP-1/GIP agonist Tirzepatide, with annual sales of $36.507 billion, overtook the “King of Drugs” title from Novo Nordisk and Merck. Novo Nordisk’s Semaglutide narrowly ranked second with just a $400 million difference.

In fact, sales data from the first half of 2025 show Semaglutide temporarily led with over $16.6 billion in sales, while Tirzepatide was close behind with nearly $15 billion. The turning point came in the fourth quarter. Lilly’s financial report revealed that Tirzepatide achieved a blockbuster $11.67 billion in sales in Q4 2025, ultimately surpassing Semaglutide.

This dramatic change reflects the fierce competition in the GLP-1 market. Specifically, both versions of Tirzepatide performed well: the glucose-lowering Mounjaro generated $22.965 billion, a 99% YoY increase; the weight-loss Zepbound reached $13.542 billion, a 175% surge. Meanwhile, the Semaglutide family includes the injectable Ozempic for glucose control, the injectable Wegovy for weight loss, and the oral Rybelsus, contributing a combined $36.1 billion in sales.

Merck’s Mounjaro, which had held the top spot for two years, fell to third place with sales of $31.68 billion in 2025, a 7% YoY increase.

The pace of “King of Drugs” iteration is accelerating. Historically, Pfizer’s lipid-lowering drug Lipitor and AbbVie’s Humira each held the “King” throne for ten consecutive years; Merck’s Mounjaro, however, only stayed in the top position for less than three years. This trend reflects the accelerated rhythm of innovation in the pharmaceutical industry. As market leaders expand at “double” the rate every two years, the window for differentiated competition among followers continues to shrink.

2

The Core of the Shift Lies in Market Demand and Growth Potential

The change of the “King of Drugs” fundamentally reflects the differing market potentials across treatment fields. Industry analysts point out that the ability of GLP-1 drugs Tirzepatide and Semaglutide to surpass tumor drugs like K drugs hinges on core differences in patient populations, market models, and competitive landscapes.

GLP-1 drugs focus on “blockbuster chronic disease medications,” targeting type 2 diabetes, obesity, and other lifestyle-related metabolic diseases. The potential patient base is in the hundreds of millions, requiring long-term medication, with ongoing expansion into new indications such as cardiovascular benefits, creating a market ceiling with immense potential. In contrast, K drugs and other PD-1 tumor drugs serve only diagnosed patients, with total market size and treatment duration limited by disease spectrum and progression.

Market attributes show that GLP-1 drugs target a vast incremental market. For example, in China, prescription rates for weight-loss indications are less than 1%. From glucose control to weight management and cardiovascular benefits, new growth curves are continuously being opened. K drugs, on the other hand, operate in mature, saturated markets. Although growth is maintained through new indications and combination therapies, single-drug sales are entering a mature phase with slowing growth.

In terms of competition, GLP-1 is currently dominated by Eli Lilly and Novo Nordisk, with the market far from saturation. Sales growth is sufficient to offset price competition. K drugs face fierce competition before patent expiry and will also endure greater patent cliff pressures. This divergence directly drives the global “King of Drugs” scepter shifting from the oncology field to metabolic diseases.

3

Intense Competition in the GLP-1 Arena

The emergence of the new “King of Drugs” is changing the flow of global drug R&D funding and strategic focus. The explosive growth of the GLP-1 sector has not only attracted increased investment from Novo Nordisk and Lilly but also prompted more companies to enter this field.

The rapid revenue generation in the GLP-1 space is unmatched. Tirzepatide reached $10 billion in sales in less than three years, and surpassed $30 billion in just one year. In comparison, K drugs took six years—from crossing $10 billion in 2019 to surpassing $30 billion in 2025.

Early 2025 data show that the global pipeline for GLP-1 drugs includes 179 candidates, a 40% YoY increase; multinational pharmaceutical companies have increased R&D investment in weight management from 12% in 2020 to 35% in 2025. Giants like Lilly, Novo Nordisk, and Pfizer have made weight management a core strategy. Pfizer plans to initiate ten Phase III trials of ultra-long-acting GLP-1 drugs in 2026, along with new drugs like Eli Lilly’s Olfogliflozin. Domestic companies also have new products in development, including Hengrui Medicine’s (600276) HRS-7535 and Wentai Pharma’s VCT220.

According to the “World Obesity Atlas 2025,” the global GLP-1 market is projected to grow from $53.46 billion in 2024 to $150 billion by 2030, with a CAGR exceeding 20%. Analysts note that GLP-1 drug innovation is moving toward multi-target approaches, longer duration, and more convenient administration, with oral formulations becoming the industry’s next core competitive focus. This shift in R&D reflects a deeper understanding of patient needs. Clinical demands such as preventing weight rebound and muscle loss are still unmet, providing space for differentiated innovation. Lilly’s ongoing development of RetaGlutide (a triple-agonist targeting GLP-1/GIP/GCGR) and Novo Nordisk’s CagriSema (a dual GLP-1/ incretin agonist) are seen as potential next-generation “Kings of Drugs.”

4

Seeking Transformation in the Tumor Immunotherapy Arena

Although the “King of Drugs” throne held by K drugs has slowed in growth, they still maintain an unshakable position in oncology. In 2025, despite dropping from the top spot, K drugs’ sales exceeded $30 billion for the first time, accounting for nearly half of Merck’s revenue. Previously, in 2023, K drugs’ global sales reached $25.011 billion, surpassing Humira for the first time to become the world’s best-selling drug; in 2024, sales hit $29.482 billion, an 18% YoY increase, maintaining the global “King” title.

However, the core patents for K drugs will expire in December 2028, though protection for two other method patents may extend to May or November 2029. Merck is actively promoting the approval of subcutaneous formulations to address patent cliffs. Clinical experts suggest that subcutaneous administration is simpler and more widely used, potentially prolonging K drugs’ dominance in the PD-1 market. Merck expects that by 2028, subcutaneous formulations could reach a penetration rate of 30-40%, with the entire K drug family potentially hitting a sales peak of $35 billion.

Meanwhile, Merck is also expanding its oncology and other disease pipelines through acquisitions and R&D to reduce reliance on a single product.

Broadly, the slowdown in K drug growth offers important insights for the future development of PD-1 and other tumor drugs: a foundation based on precise stratification, core reliance on combination therapies, and full disease course management. For domestic companies, differentiation and global deployment are essential to secure a foothold in the second half of tumor immunotherapy.

5

China Becomes a Key Battlefield for the “King of Drugs”

Against the backdrop of the global “King of Drugs” transition, China is becoming an important battleground for GLP-1 drug competition. Novo Nordisk leads in China’s market for diabetes treatment GLP-1 drugs and insulin. Price competition is particularly fierce in China. Since November 2025, Novo Nordisk and Lilly have consecutively reduced prices for Semaglutide and Tirzepatide to capture market share.

Data show that the sales of Ozempic (injectable for glucose control) in China reached 5.399 billion Danish kroner (about RMB 5.939 billion); Rybelsus (oral for glucose control) sales were approximately 620 million Danish kroner (about RMB 682 million), a 27% YoY increase; Wegovy (injectable for weight loss) sales in China reached about 796 million Danish kroner (about RMB 8.76 billion), a 314% YoY increase.

Analysts believe that the GLP-1 track has shifted from an early “blue ocean” market to a new stage of fierce competition. For domestic pharmaceutical companies, this is both a challenge and an opportunity. Accelerating innovation and seeking differentiated advantages in GLP-1 are crucial for capturing a share in the global market.

For K drugs, China—the world’s second-largest tumor drug market—is especially critical. In 2025, Merck’s total revenue in China was $1.816 billion (about RMB 12.8 billion). As Merck’s sole growth pillar in China, K drugs’ sales in 2025 are estimated between $1.1 billion and $1.3 billion (about RMB 7.7–9.1 billion), accounting for 3.5%–4.1% of Merck’s global sales and 60%–72% of Merck’s total revenue in China.

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The 2026 “King of Drugs” Is Already Locked in Ahead of Time

Tirzepatide has been pre-locked as the 2026 sales champion. With Tirzepatide claiming the 2025 “King of Drugs” throne, the competitive landscape for 2026 is beginning to take shape. Lilly has provided a full-year revenue guidance of $80–83 billion for 2026. Although this growth rate has slowed compared to 2025’s 41%, it remains a steep growth curve, setting a new record for annual revenue in the pharmaceutical industry. This indicates that Tirzepatide has secured the 2026 global “King of Drugs” throne ahead of schedule.

A prediction by the journal Nature Reviews Drug Discovery at the end of 2024 estimated that Lilly’s Tirzepatide (including the glucose-lowering Mounjaro and weight-loss Zepbound) would reach a combined sales total of $31.1 billion in 2025, but actual sales hit $36.5 billion, far exceeding expectations. The forecast for 2026 was $45.5 billion for Tirzepatide, $35.1 billion for Semaglutide, and $33.8 billion for K drugs, still favoring Tirzepatide as the “King of Drugs.”

Industry insiders believe that the handover of the global “King of Drugs” scepter will not stop. In an era of accelerated pharmaceutical innovation, there is no eternal throne—only an ongoing race of innovation.