Merck Just Spent $6.7 Billion on a Cancer Drug Most People Haven't Heard Of

To understand why Merck wrote this check, you need to understand its biggest existential problem: Keytruda.

Keytruda is the best-selling cancer drug on the planet. It brought in over $30 billion in sales in 2025 alone. It's also facing a patent cliff toward the end of the decade, which means generic and biosimilar competition is coming. Replacing $30 billion in annual revenue is like trying to fill a swimming pool with a garden hose; you need a lot of hoses running at once.

Merck's strategy has been to buy its way into new therapeutic areas at a furious pace. EyeBio for ophthalmology. Prometheus for immunology. Verona Pharma for respiratory disease. Harpoon Therapeutics for T-cell engagers. The company recently split its entire human health business into separate oncology and infectious disease divisions, just to sharpen its focus.

The Terns deal slots directly into this playbook. BMO Capital Markets analysts estimate TERN-701 could hit peak sales above $4 billion, which would make it one of Merck's most meaningful post-Keytruda growth drivers. It wouldn't fill the whole pool, but it would be one very big hose.

Wall Street Thinks Merck Got a Bargain

At $53 per share, Merck paid a 31% premium to Terns' 60-day average trading price and 42% over the 90-day average. That sounds generous until you hear what analysts are saying.

William Blair's team argued the price "does not fully capture the potential of TERN-701." Translation: Merck got a deal. BMO called it "one of the best deals Merck has made" in its entire pre-Keytruda-cliff acquisition spree. RBC Capital Markets noted that buying before full dose escalation data shows "high confidence in the asset," while also pointing out the price could have attracted competing bids from the likes of AbbVie or Bristol Myers Squibb.

The accounting is worth noting. Merck is treating this as an asset acquisition (not a traditional merger), which triggers a roughly $5.8 billion R&D charge on its 2026 books. That's about $2.35 per share in one-time pain. It'll dent this year's earnings, but Wall Street is looking past the near-term hit to the long-term payoff.

The MASH Road Not Taken

There's a fascinating "what if" buried in this story. Before pivoting to oncology, Terns had genuinely interesting metabolic assets. Its MASH drug, TERN-501, showed impressive liver fat reduction in a Phase 2a trial: the highest dose cut liver fat by nearly 45% compared to just 4% for placebo. Its oral GLP-1 pill, TERN-601, had entered Phase 2 trials for obesity.

But the MASH space got brutally crowded. Madrigal's Rezdiffra became the first FDA-approved MASH drug in 2024. Novo Nordisk's Wegovy snagged a MASH label in 2025. Roche spent $3.5 billion on 89bio. Novo paid up to $5.2 billion for Akero. GSK bought into FGF21 assets. By the time Terns looked around, the land grab was mostly over.

So Terns made what looks, in hindsight, like a brilliant calculated retreat. It walked away from a crowded field and bet everything on a differentiated oncology asset in a space with clear unmet need. That bet just paid off at $6.7 billion.

What Happens Next

The deal, structured as a tender offer followed by a merger, already has unanimous board approval from both companies. Closing was targeted for the second quarter of 2026, and subsequent reports indicate it has already been completed. Terns stock has been delisted from Nasdaq. The company now operates as a wholly owned Merck subsidiary.

For Merck, the real work starts now: advancing TERN-701 through later-stage trials and, eventually, toward regulatory approval. The clinical risk is real; this is still a relatively early-stage asset. But with BMO projecting $4 billion-plus in peak sales and multiple analysts calling the deal underpriced, the market seems to think Merck's odds are pretty good.

The bigger picture is what this says about the current state of Big Pharma dealmaking. Companies facing patent cliffs aren't waiting for late-stage, de-risked assets anymore. They're buying earlier, paying bigger premiums, and betting on scientific conviction over clinical certainty. It's a high-stakes poker game, and Merck just pushed a very large stack of chips to the center of the table.

Gilead Just Dropped $2.18 Billion on a Company You've Never Heard Of

Gilead just agreed to pay up to $2.2 billion for Ouro Medicines, a startup that's barely a year old. The deal centers on an "immune reset" drug that could reshape how we treat autoimmune diseases, and Gilead isn't even paying the full tab.