Merck (NYSE:MRK) announced Monday that it will reorganize its human health operations into two distinct units, establishing a dedicated oncology division centered on its flagship cancer therapy Keytruda, while placing its remaining medicines into a separate non-oncology business.
The restructuring highlights the U.S. pharmaceutical company’s effort to reduce reliance on Keytruda as the drug approaches the end of its market exclusivity later this decade.
Keytruda, approved for multiple cancer indications, is currently the world’s top-selling prescription drug. The therapy generated more than $30 billion in revenue in 2025, representing nearly half of Merck’s overall sales.
Merck shares rose 1.4% in premarket trading following the announcement.
Since 2021, the company has significantly expanded its development pipeline and completed two major acquisitions valued at around $10 billion last year, purchasing Cidara Therapeutics and Verona Pharma to strengthen and diversify its portfolio.
The organizational overhaul comes after Merck issued a cautious outlook for 2026 earlier this month, warning that revenue and profit could come under pressure as several older products near patent expiry and face increasing generic competition.
Merck also named Jannie Oosthuizen as executive vice president and president of the newly formed oncology division. Oosthuizen previously served as senior vice president and president of Merck Human Health U.S., where he oversaw strategy and commercialization for the company’s U.S. portfolio.
The restructuring plans were first reported earlier in the day by The Wall Street Journal.