Merck KGaA, Darmstadt, Germany, has agreed to acquire Silence Therapeutics, a UK-based biotechnology company, in an all-cash deal valued at approximately $1.3 billion. The acquisition will strengthen Merck’s rare disease drug pipeline by adding an experimental gene-silencing treatment for polycythemia vera, a rare blood cancer.
Announced on October 19, 2026, the deal values Silence Therapeutics at an enterprise value of $1.1 billion and an equity value of approximately $1.3 billion. Under the agreement, Merck will pay $20 in cash for each American Depositary Share (ADS) of Silence Therapeutics. The offer represents a 130% premium to the company’s closing share price on October 16, 2026.
The acquisition will give Merck access to Silence Therapeutics’ short interfering RNA (siRNA) technology, which is designed to switch off specific genes involved in disease. Unlike conventional medicines that often target proteins or their activity, siRNA therapies work by reducing the production of selected proteins before they can cause harmful effects.
A key asset in the deal is divesiran, an investigational siRNA therapy being developed for patients with polycythemia vera who require regular blood removal, known as phlebotomy, to manage their condition.
Polycythemia vera is a rare blood cancer in which the bone marrow produces too many red blood cells. This can increase blood thickness and raise the risk of blood clots and cardiovascular complications. Patients may also experience symptoms such as fatigue, itching and difficulty concentrating.
Divesiran has shown encouraging results in Phase 2 clinical studies and is being prepared for Phase 3 development. Merck plans to advance the treatment into late-stage clinical testing, with the aim of bringing a new option to patients who need better treatment choices.
The acquisition will also expand Merck’s broader siRNA pipeline and provide access to Silence Therapeutics’ mRNAi GOLD platform. The company is developing additional RNA-based treatments for conditions involving high lipoprotein(a), elevated cholesterol, obesity and immune-related diseases.
Merck said the planned acquisition supports its strategy of expanding its healthcare business in specialised treatment areas with significant unmet medical needs. The company has increasingly focused on external innovation and acquisitions to strengthen its drug development pipeline.
The transaction follows Merck’s acquisition of SpringWorks Therapeutics in 2025, further highlighting its interest in specialised medicines and rare diseases.
The deal is expected to close in the first quarter of 2027, subject to approval by Silence Therapeutics shareholders, the UK High Court, regulatory authorities and other customary closing conditions.
If completed, the acquisition will give Merck a stronger position in RNA-based medicines and expand its opportunities in rare disease treatment. The progress of divesiran through Phase 3 development will be an important next step in determining the potential of this technology for patients with polycythemia vera.