Strong growth across multiple cancer indications as well as price rises saw Merck & Co’s PD-1 inhibitor Keytruda (pembrolizumab) increase its revenues by 18% in 2024, putting it more than $12bn ahead of its closest rival for the position of best-selling drug globally.
The GLP-1 inhibitors continued to exert their force over the global medicines market. Novo Nordisk’s Ozempic (semaglutide) for type 2 diabetes grew by 26% to reach second place at the same time as Eli Lilly’s more recently launched competitor Mounjaro (tirzepatide) more than doubled its annual sales and entered the top 20 for the first time in eighth position. Novo’s semaglutide for obesity, Wegovy, also featured in the top 20 for the first time, in 16th place, although Lilly’s Zepbound rival has yet to break into the top ranks.
Obesity Rivals COVID-19 Windfall
Accounting for $37.5bn, or 16%, of total top-20 drug revenues in 2024, GLP-1 drugs for diabetes and obesity more than offset the loss of $18.4bn contributed by COVID-19 vaccines in 2023.
Overall, worldwide sales of the top 20 products were up by 10% in 2024, while the top 10 product sales grew by 9%. However, they failed to reach the levels seen in 2022, when the staggering $78.6bn in global sales of COVID-19 vaccines and treatments swelled top 20 drug sales to $249.2bn in total and top 10 drug sales to $173.2bn.
Gardasil Slips
It was not all good news for Merck & Co in 2024: its human papillomavirus (HPV) vaccine Gardasil/Gardasil 9 saw a drop in revenues from $8.9bn to $8.6bn in 2024, reflecting lower demand in China. Furthermore, high inventory levels at its commercialization partner in China, Chongquing Zhifei Biological Products, prompted it to pause shipments to China from February 2025 until at least the middle of the year, meaning that the product’s revenues are expected to decline significantly in 2025.
Also on the slide were AbbVie’s Humira (adalimumab), which continues to drop in the rankings after some losing US exclusivity in early 2023, and Johnson & Johnson’s Stelara (ustekinumab), another immunology drug with mounting exclusivity challenges. AbbVie has been able to replace some of the lost revenues with the increasing returns from its newer immunology drug Skyrizi (resankizumab), while the growth of multiple myeloma drug Darzalex (daratumumab) has provided some succor for Johnson & Johnson.
Tagrisso, Trikafta Rise; Trulicity Sinks
AstraZeneca’s non-small cell lung cancer drug Tagrisso (osimertinib) made its debut in the top 20 best-selling drugs in 2024 after posting 13% sales growth based on growth in both adjuvant and metastatic settings across different geographies. Another strong performer was Vertex Pharmaceuticals’ cystic fibrosis treatment, Trikafta/Kaftrio (elexacaftor/tezacaftor/ivacaftor), up 11% in its main market, the US, thanks to both strong patient demand and higher net realized pricing, and up 13% outside the US.
Eli Lilly’s success with its dual GLP-1/GIP tirzepatide drugs, Mounjaro and Zepbound, had a knock-on effect on its earlier GLP-1 agonist Trulicity (dulaglutide). The diabetes drug experienced a 26% drop in sales to $5.3bn in 2024, reflecting “competitive dynamics” - and exited the top 20.
Also out of the top 20 in 2024 were two COVID-19 vaccines, Pfizer/BioNTech’s Comirnaty and Moderna’s Spikevax, as well as Pfizer’s Prevnar vaccines for pneumococcal disease.
Quarterly Sales Trends
Among the 10 drugs that had the highest quarterly sales globally, Novo Nordisk’s Wegovy was a notable new entrant in the fourth quarter, whereas J&J’s Stelara was notable by its absence, reflecting the onset of biosimilar competition in Europe from the summer of 2024.
Although it did not feature in the annual top 20, fourth-quarter sales of Comirnaty propelled it into seventh place overall for the quarter. However, the massive seasonal spikes in revenues from the vaccine are becoming more modest each time and fall far short of the $12bn+ in quarterly revenues generated in late 2021 and early 2022.
Quarterly growth patterns for Ozempic, Mounjaro and Wegovy over the past three years reflect rapid growth in demand tempered by supply constraints but all three products experienced quarter-on-quarter growth in the fourth quarter. Keytruda and to a lesser extent Darzalex have proceeded with generally steady strong growth each quarter over the past three years, while Skyrizi has grown particularly rapidly over the past year.
Keytruda To Maintain Lead, Obesity Swells
Looking forward to expectations of full-year product sales, Keytruda is on track comfortably to retain its number one spot in 2025 and 2026, with sales rising to $31.8bn in 2025 and $33.1bn in 2026. At the same time, its old PD-1 inhibitor rival Opdivo (nivolumab, Bristol Myers Squibb) is expected to fall from 11th place in 2024 to 12th place in 2025 and 2026.
As a combined force the GLP-1 diabetes/obesity drugs from Novo Nordisk and Lilly will become ever stronger. All four currently marketed drugs – Ozempic, Mounjaro, Wegovy and Zepbound – are predicted to feature in the top 10 line-up for 2025, with total sales across the products of $62.6bn according to analyst consensus estimates collated by Evaluate Pharma. This figure is forecast to rise to $78.8bn in 2026.
Making way for Wegovy and Zepbound in the 2025 top 10 are expected to be Stelara and Trikafta.
The only drug that is expected to see sales decline from 2025 to 2026 is Bristol Myers Squibb/Pfizer’s anticoagulant Eliquis (apixaban).
