Betting on next-generation siRNA therapy, Merck KGaA, Darmstadt, Germany, has agreed to acquire London-based biotechnology company Silence Therapeutics plc in a deal valued at approximately $1.3 billion in equity.

 

The deal strengthens the healthcare major's push into specialty medicines and rare diseases.

 

Under the definitive agreement, Merck will pay $20 in cash for each American Depositary Share (ADS) of Silence Therapeutics, with each ADS representing three ordinary shares. The offer values Silence at an enterprise value of $1.1 billion and represents an 82% premium to its 30-day volume-weighted average share price of $10.99 as of October 16, 2026.

 

The acquisition will give Merck access to Divesiran, an investigational small interfering RNA (siRNA) therapy designed to treat phlebotomy-dependent polycythemia vera (PV), a rare blood cancer. The drug is potentially best-in-class and ready to advance towards Phase 3 development, according to the companies.

 

“The planned acquisition of Silence Therapeutics will strengthen our capabilities to serve patients with targeted specialty and rare diseases,” said Kai Beckmann, Chairman of the Executive Board and Group CEO of Merck KGaA, Darmstadt, Germany. 

 

“Following the acquisition of SpringWorks Therapeutics last year, we continue to transform our pipeline toward areas of high specialization and unmet medical need, with an ongoing commitment to external innovation. The proposed transaction follows our strategic priority to address attractive end markets also through M&A, creating value over the mid- to long-term.”

 

Divesiran emerged as the centrepiece of the deal following positive Phase 2 results in the SANRECO study. The therapy achieved an 88% responder rate, compared with 19% for placebo, meeting the trial's primary endpoint.

 

It also reduced the average number of therapeutic phlebotomies — procedures used to remove blood to control red blood cell levels — to 0.2 per patient, compared with 2.1 for placebo over weeks 0–36. The results held irrespective of background cytoreductive therapy.

 

The treatment was reported to be well tolerated, with no new safety findings observed during the trial. Injection-site reactions were infrequent and self-limiting. Investigators assessed two cases of Grade 1 anaemia as related to treatment.

 

Divesiran is designed to silence TMPRSS6, a gene involved in regulating hepcidin, a key hormone controlling iron metabolism. By increasing hepcidin levels, the therapy aims to restrict iron availability for red blood cell production, control haematocrit levels and potentially reduce patients’ dependence on repeated blood-removal procedures.

 

PV is a chronic myeloproliferative neoplasm characterised by excessive red blood cell production and associated with an increased risk of cardiovascular and thrombotic events. Divesiran is administered as a subcutaneous injection once every three months, a dosing schedule that could offer a less burdensome treatment option for patients if its clinical benefits are confirmed.

 

“The planned acquisition of Silence Therapeutics marks a significant step forward in our strategy to become a Global Specialty Innovator in Healthcare,” said Danny Bar-Zohar, member of the Executive Board and CEO Healthcare at Merck KGaA, Darmstadt, Germany. 

 

“Silence Therapeutics’ primary siRNA pipeline asset, Divesiran, is supported by promising Phase 2 efficacy data, a potentially best-in-class, once-every-three-month dosing schedule, and a safety profile that appears manageable, with the added advantage of targeting a well-defined, homogeneous patient population. 

 

"The planned acquisition also provides an entry point into hematology through a biologically validated mechanism of action. With this transaction, we are advancing our efforts to build a differentiated, sustainable pipeline as we bring more medicines to more patients, faster.”

 

For Silence Therapeutics, the agreement marks a new chapter for its siRNA platform and pipeline, placing its lead programme under the ownership of a company with the resources and commercial infrastructure to support late-stage development and potential market launch.

 

“We are pleased to have reached this agreement with Merck KGaA, Darmstadt, Germany, which follows a competitive sale process and delivers significant, immediate and certain value to our shareholders,” said Iain Ross, Interim Principal Executive Officer and Chairman of the Silence Therapeutics’ Board. 

 

“This transaction follows potentially best-in-class Phase 2 polycythemia vera data for Divesiran and reflects the important progress we have made advancing our differentiated siRNA pipeline. 

 

"It also provides a new home for our innovative programs within Merck KGaA, Darmstadt, Germany, placing Divesiran with a company that has the scale, resources and commercial capabilities to accelerate its Phase 3 development and bring this potentially best-in-class siRNA therapy to patients in need."