Merck KGaA agrees to acquire Silence Therapeutics for US$1.3B to expand RNA medicines portfolio

USA—Merck KGaA has agreed to acquire British biotechnology company Silence Therapeutics for US$1.3 billion in an all-cash deal, gaining access to experimental RNA medicines targeting rare diseases and cardiovascular conditions.

Under the agreement, Merck will pay US$20 per American Depositary Share (ADS), with each ADS representing three ordinary shares in Silence, an 82% premium to Silence’s average share price over the preceding month.

Divesiran leads Silence’s clinical pipeline

The acquisition gives Merck access to divesiran, an investigational small interfering RNA (siRNA) therapy for polycythemia vera (PV), a rare blood cancer characterised by excessive red blood cell production.

In August, Silence reported positive Phase II trial results (NCT05499013), with 88% of patients receiving divesiran meeting the study’s clinical response criteria, compared with 19% in the placebo group.

PV can increase the risk of blood clots and cardiovascular complications. Divesiran is designed to silence the TMPRSS6 gene, which regulates iron metabolism.

By reducing its activity, the therapy aims to limit iron availability for red blood cell production.

The candidate could offer a different approach to treating PV, as Takeda and Protagonist Therapeutics are developing Mimrylo (rusfertide) for the market.

Approved in the United States in August, the peptide therapy mimics hepcidin, a hormone that regulates iron levels.

Takeda projects peak annual sales of US$1 billion to US$2 billion for the treatment.

William Blair analysts described divesiran as a potential leading candidate in its class.

They also noted that Merck’s acquisition includes Silence’s broader mRNAi GOLD siRNA platform, which could support the development of additional medicines.

RNA platform expands Merck’s pipeline

SiRNA medicines work by targeting specific genetic messages, preventing cells from producing selected proteins.

Silence’s other advanced candidate, zerlasiran, is undergoing Phase II evaluation (NCT05537571) to reduce elevated levels of lipoprotein(a), a blood particle associated with increased cardiovascular risk.

Merck chief executive Kai Beckmann said the planned acquisition would strengthen the company’s capabilities in targeted therapies for specialist and rare diseases.

The deal forms part of a wider expansion strategy.

In July 2025, Merck acquired rare disease specialist SpringWorks Therapeutics for US$3.9 billion.

In June 2026, it agreed to acquire life sciences company Bio-Techne for US$11.3 billion, marking another major investment in its healthcare and life sciences businesses.

UK biotech acquisitions gather pace

Founded in London in 1994, Silence Therapeutics joins a series of British biotechnology companies acquired by larger pharmaceutical groups.

In January 2026, Amgen agreed to acquire Dark Blue Therapeutics for up to US$840 million.

Eli Lilly subsequently agreed to buy Centessa Pharmaceuticals for US$6.3 billion in June.

For Merck, the Silence transaction adds an RNA-based drug discovery platform and clinical-stage candidates to its portfolio, extending its reach into genetic medicines and specialised disease markets.

Sign up HERE to receive our email newsletters with the latest news and insights from Africa and around the world, and follow us on LinkedIn for updates.