Merck to buy siRNA specialist Silence Therapeutics for $1.3 billion
Merck will acquire Silence Therapeutics for $1.3 billion ($20 per ADS) in cash, with the deal expected to close in Q1 2027. The acquisition is driven by Silence's siRNA drug candidate divesiran, which showed promising results in a Phase 2 trial for polycythemia vera. Merck aims to advance divesiran into Phase 3 trials and potentially commercialize it, while also gaining access to Silence's other drug candidates, including zerlasiran.
How this was made

The 30-second read
Why it matters
The deal could boost Merck's long‑term growth prospects while short‑term stock reaction will depend on investor appetite for cash‑heavy acquisitions.
Market read
First‑report M&A of over $1 billion, adding a new therapeutic modality to a major pharma, likely to move Merck's stock and affect biotech sector sentiment.
What to watch
Regulatory approval risk for divesiran and the need for additional funding for Phase 3 could delay value realization.
Background
Merck seeks to diversify its portfolio beyond oncology and vaccines by entering the hematology market with a novel siRNA therapy.
Ticker impact
Merck announced a cash deal to acquire Silence Therapeutics for $1.3 billion, expanding into hematology.
potential modest upside as investors price in the strategic expansion and pipeline value
Deal size is material and first disclosed today; market typically reacts positively to strategic acquisitions with strong data.
Market effects
Strengthens Merck's position in the biotech/hematology space and may spur interest in other siRNA developers.
European biotech sector could see increased attention as a high‑profile US pharma backs a UK‑based company.
Adds to the broader trend of large pharma acquiring RNA‑interference platforms, influencing global M&A activity.
Counterpoint
The cash price may be high relative to Silence's early‑stage pipeline, potentially diluting Merck's balance sheet.
Key entities
- CompanyMerck & Co.
US‑listed pharmaceutical giant acquiring Silence Therapeutics.
- CompanySilence Therapeutics
London‑based siRNA developer with Phase 2 data for divesiran.





