Germany's Merck buys Silence Therapeutics in $1.3 billion RNA drug deal

By Christy Santhosh

Oct 19 (Reuters) - German drugmaker Merck KGaA said on Monday it would acquire UK-based Silence Therapeutics in an all-cash deal for about $1.3 billion, bolstering its pipeline of precision medicines and adding RNA-targeting drug technology.

Merck will pay $20 per American depositary share for Silence, representing a premium of 130% to the stock's last close. US-listed shares of Silence more than doubled in morning trading.

The deal broadens Merck's gene-silencing capabilities by adding Silence's siRNA medicines, which work by switching off disease-related gene messages before they can produce harmful proteins.

RNA, or ribonucleic acid, is a molecule that carries genetic instructions and helps tell cells which proteins to make.

This is Merck's third major acquisition in less than two years, following its $3.9 billion purchase of SpringWorks Therapeutics in 2025 and its pending $11.3 billion takeover of life-sciences tools maker Bio-Techne.

Silence's lead therapy candidate, divesiran, is expected to enter late-stage testing for phlebotomy-dependent polycythemia vera, or PV, a rare blood cancer in which the bone marrow produces too many red blood cells.

Patients with this condition require regular therapeutic blood draws, known as phlebotomies, to manage their red blood cell levels.

With an approval, the drug would compete with Takeda and Protagonist's rival drug, Mimrylo.

"With Takeda implying $1 billion to $2 billion in peak sales for Mimrylo in PV, the deal valuation does appear inexpensive considering Merck KGaA also gets the broader mRNAi GOLD siRNA platform as well," said William Blair analyst Myles Minter.

Minter said the deal "takes the execution risk off the table in an increasingly competitive space".

Silence is also developing zerlasiran for people with high lipoprotein(a), a blood protein linked to heart disease, along with earlier-stage treatments for high cholesterol, obesity and immune-related diseases.

The deal is expected to close in the first quarter of 2027. The companies said the transaction will be effected through a UK scheme of arrangement.

(Reporting by Christy Santhosh in Bengaluru; Editing by Devika Syamnath and Maju Samuel)