In a strategic move to bolster its oncology pipeline, Merck has entered into a definitive agreement to acquire Terns Pharmaceuticals in an all-cash deal worth roughly $6.7 billion. The transaction, announced on March 25, 2026, offers Terns shareholders $53 for each share they hold.
Addressing the Looming Patent Cliff
The timing of this acquisition is critical for Merck. The company's top-selling cancer immunotherapy, Keytruda, is scheduled to begin facing patent expirations in 2028. In the previous year, Keytruda generated over $30 billion in revenue, accounting for nearly half of Merck's total sales. This impending loss of exclusivity has pressured the pharmaceutical giant to secure new growth drivers within its core therapeutic area of oncology.
Deal Structure and Financials
Merck stated the net value of the offer is approximately $5.7 billion after accounting for Terns' existing cash reserves. The acquisition will be executed through a tender offer, where a Merck subsidiary will directly solicit shares from Terns stockholders. The deal remains contingent on regulatory antitrust approval and requires support from holders of more than 50% of Terns' outstanding shares. Merck anticipates closing the transaction during the second quarter of 2026 and expects to record a one-time charge of about $5.8 billion.
The Prize: TERN-701
At the heart of this deal is TERN-701, an oral treatment candidate for chronic myeloid leukemia (CML), a cancer of the blood and bone marrow. The drug is currently in early-stage clinical development. Preliminary data reported a 75% response rate among patients who had received prior therapies. Dean Li, Merck's head of research, highlighted that the initial results suggest TERN-701 could offer a potentially differentiated treatment pathway for specific CML patient populations.
If subsequent clinical trials confirm its efficacy and safety profile, TERN-701 could position Merck to compete with Novartis in a specialized segment of blood-cancer treatment. Novartis's Scemblix is already an established therapy in this space. Analyst Andy Hsieh of William Blair noted "unequivocal improvement in both efficacy and safety" for the Terns drug, while RBC's Trung Huynh characterized the acquisition as "strategically sound and incrementally positive" for Merck.
Premium and Market Reaction
The $53 per share bid represents a modest 6% premium over Terns' closing price on the Tuesday before the announcement. Following the news, Terns' stock rose 5.5% in premarket trading. Merck emphasized that the offer price reflects a 31% premium to Terns' 60-day average share price and a 42% premium to its 90-day average. The relatively narrow premium has led some observers, including analyst Huynh, to suggest it "could open the door" for potential competing bids, though the transaction is already advanced.
Strategic Context and Recent Activity
This acquisition marks the latest in a series of strategic deals by Merck designed to mitigate the commercial impact of Keytruda's patent cliff. In July 2025, the company acquired Verona Pharma for approximately $10 billion. This was followed by a deal for Cidara Therapeutics in November of the same year, valued at close to $9.2 billion. While Merck continues to explore therapeutic areas beyond cancer, oncology remains the central pillar of its long-term strategy.
Internally, Merck recently reorganized its human-health division, splitting it into two dedicated units: one focused exclusively on oncology and the other on all other therapeutic areas. This structural change underscores the paramount importance of cancer drugs to Merck's future, even as it seeks to diversify its revenue sources.
The acquisition carries inherent risks, as TERN-701 has not yet progressed beyond early clinical trials. Many oncology drug candidates fail in later-stage studies as development scales up. The deal still requires final regulatory clearance and successful completion of the tender offer process. Nevertheless, the transaction underscores Merck's aggressive and costly pursuit of new assets to sustain its market leadership post-Keytruda.
