Merck KGaA to Buy Silence Therapeutics for $20 a Share, Betting on RNAi Drug for Polycythemia Vera

What happened

Merck KGaA, the German science and technology company, announced on Monday, Oct. 19, that it has agreed to acquire Silence Therapeutics, a developer of RNA interference medicines. According to BioPharma Dive, Merck KGaA will pay $20 in cash for each U.S.-listed Silence share, valuing the deal at $1.3 billion. The price represents a 130% premium, the second-highest among the larger deals BioPharma Dive has tracked this year.

Shareholders representing 14% of Silence’s voting power have already agreed to the transaction, which is expected to close in the first quarter of 2027.

Deal details

• Price: $20 per U.S.-listed share in cash.
• Total value: $1.3 billion.
• Premium: 130%.
• Support: Holders of 14% of voting power have agreed to the deal.
• Timing: Expected to close in the first quarter of 2027.

BioSpace also covered the deal on Oct. 19, describing it as a move into hematology for Merck KGaA.

The asset

The main asset is divesiran, a short-interfering RNA therapy for polycythemia vera, a rare blood cancer in which the body produces too many red blood cells. Divesiran silences TMPRSS6, which raises levels of the hormone hepcidin and suppresses iron metabolism. In a Phase 2 trial, it significantly reduced the number of blood draws patients needed compared with placebo, according to BioPharma Dive. Analysts at Cantor Fitzgerald said its efficacy “meaningfully exceeded” that shown by Takeda and Protagonist’s Mimrylo.

Silence will need to fund a Phase 3 program. BioPharma Dive noted that the company had $72 million in cash and equivalents as of June 30, a modest sum relative to the cost of late-stage trials.

Why it matters for the sector

Merck KGaA chief executive Kai Beckmann described the acquisition as part of an effort to transform the company’s pipeline toward areas of high specialization and unmet medical need. It follows the company’s 2025 buyout of SpringWorks Therapeutics, which brought in approved drugs. Earlier in 2026, Merck KGaA also agreed to acquire life science tools company Bio-Techne.

The steep premium reflects both the low valuation at which Silence had been trading and the buyer’s confidence in divesiran. Small-cap biotechs with promising mid-stage data but limited cash often trade at depressed prices, which can make them attractive targets for acquirers that can fund Phase 3 development.

Polycythemia vera is currently managed with regular phlebotomy and drugs such as hydroxyurea and JAK inhibitors. Therapies that reduce or eliminate the need for blood draws by targeting iron regulation, including Takeda and Protagonist’s Mimrylo, have become a competitive area, and the Silence acquisition gives Merck KGaA a position in it.

The deal is also an endorsement of RNA interference as a platform. siRNA drugs, which silence specific genes for extended periods after a single dose, have moved from rare liver diseases into larger indications, and acquirers are increasingly willing to pay for late-stage RNAi assets.

The transaction was announced on a busy day for dealmaking. Roche disclosed a broad antibody-drug conjugate partnership with Hansoh Pharma valued at more than $15 billion, and Eli Lilly announced a lipid nanoparticle delivery deal with METiS TechBio.

What to watch

• Silence shareholder and regulatory approvals ahead of the expected first-quarter 2027 close.
• Merck KGaA’s Phase 3 plans for divesiran.
• Competitive developments in polycythemia vera, including Mimrylo’s commercial performance.
• Further acquisitions by Merck KGaA in specialized therapeutic areas.

This article is for information only and is not investment advice.

Sources: BioPharma Dive, BioSpace

Understanding Polycythemia Vera

Polycythemia vera is a type of chronic blood cancer called a myeloproliferative neoplasm. Most patients carry an acquired mutation in the JAK2 gene that causes the bone marrow to overproduce blood cells, especially red blood cells. Thicker blood raises the risk of clots, strokes and heart attacks, and patients can also experience fatigue, itching, headaches and an enlarged spleen.

How it is usually managed

• Phlebotomy. Regular removal of blood lowers the proportion of red cells, a measure called hematocrit, toward a target level set by the physician.
• Medications. Drugs such as hydroxyurea and JAK inhibitors reduce blood cell production in patients who need more than phlebotomy.
• Aspirin. Low-dose aspirin is often used to reduce clotting risk.

Frequent phlebotomy can be burdensome and, over time, leaves patients iron deficient, which can cause its own symptoms. Patients should follow the plan set by their hematologist.

Why Targeting Iron Regulation Works

Red blood cell production depends on iron. The hormone hepcidin, made in the liver, acts as the body’s iron gatekeeper: when hepcidin rises, less iron is absorbed from food and less is released from storage, so less is available to build red cells.

TMPRSS6 is an enzyme that normally keeps hepcidin levels in check. Silencing TMPRSS6 with an siRNA allows hepcidin to rise, which restricts iron supply to the bone marrow and slows red cell production. The aim is to control red cell counts with fewer blood draws. Other approaches in the same area mimic hepcidin directly. All of these therapies must balance red cell control against effects on the body’s broader iron needs.

Reading a Takeover Premium

A 130% premium means the offer price is 2.3 times the price at which the shares traded before the deal was announced, typically measured against the prior closing price or a recent average. Premiums of that size usually reflect a gap between how the public market valued a company and how a strategic buyer values its assets. For small companies with promising data but limited cash, the market often discounts the risk of financing an expensive Phase 3. A buyer that can fund the trial itself removes that risk, which can justify a much higher price.

Questions Readers Ask

What does it mean that holders of 14% have agreed?

Certain shareholders have committed in advance to support the deal, which improves the likelihood of approval when all shareholders vote.

Why does Silence’s cash position matter?

With limited cash relative to Phase 3 costs, the company would likely have needed to raise money or find a partner. An acquisition resolves that question.

What is a U.S.-listed share in this context?

Some non-U.S. companies list shares in the United States in a form that represents underlying shares traded elsewhere. The offer price is expressed per U.S.-listed share.

This article is for general information only and is not medical or investment advice.