Silence Therapeutics’ lead siRNA asset for the rare blood cancer polycythemia vera has been earning analyst raves in a tight race to challenge Takeda in a potential $2 billion market.
Germany’s Merck KGaA is making a commotion in the rare disease space with the $1.1 billion acquisition of RNA specialist Silence Therapeutics and the biotech’s Phase 3 asset for polycythemia vera divesiran.
The deal gives Merck KGaA “an entry point into hematology,” Danny Bar-Zohar, member of the pharma’s executive board and CEO of healthcare, said in a Monday statement.
U.K.-based Silence focuses on short interfering RNA (siRNA), developing therapies designed to quiet disease-associated genes without permanently altering DNA.
Silence investors will receive $20 per share, representing an 82% premium on the biotech’s 30-day average price of $10.99, according to a Monday press release. The $1.1 billion represents the enterprise value while Merck KGaA noted that the equity value is about $1.3 billion. The deal is expected to close in the first quarter of 2027.
“We believe that the deal makes sense for Silence ADS holders given the interest in divesiran in polycythemia vera (PV) and need to conduct a Phase III trial in a competitive space with likely new CEO leadership,” William Blair wrote Monday morning.
Silence has been helmed by interim executive officer Iain Ross since December 2025, when CEO Craig Tooman agreed to depart the company.
Merck KGaA will gain a clutch of rare disease assets, including divesiran, which is currently in Phase 2 development for PV and in earlier-stage research for other blood disorders. Silence also has four cardiometabolic programs, led by mid-stage candidate zerlasiran.
Silence also has a partnership with AstraZeneca to develop therapies for cardiovascular, cardiometabolic, renal and respiratory diseases. The pharma recently handed Silence back the rights to SLN312, which is in Phase 1 testing for dyslipidemia.
Merck KGaA’s recent deals have centered on the rare disease space, including the 2025 acquisition of SpringWorks Therapeutics that delivered a drug for the rare tumor disease neurofibromatosis.
“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,” Kai Beckmann, chairman of Merck KGaA’s executive board and group CEO, said on Monday. “The proposed transaction follows our strategic priority to address attractive end markets also through M&A, creating value over the mid- to long-term.”
Indeed, analysts pointed to Merck KGaA as a likely buyer a year ago after the pharma suffered a series of clinical blows, such as the failure and discontinuation of evobrutinib in multiple sclerosis.
The deal comes just as Silence’s rival in PV, Disc Medicine, scored a major clinical win in erythropoietic protoporphyria. The two have been trading clinical data in PV, with analysts declaring Silence’s divesiran the likely front runner in the race to market. PV is a rare type of blood cancer, or chronic myeloproliferative neoplasm, characterized by the proliferation of red blood cells that can lead to elevated hematocrit levels. This can in turn lead to an increased risk of death from cardiovascular and thrombotic events.
In August, Silence reported that divesiran led to an 88% clinical response rate in treated patients, compared with 19% in placebo controls, during the Phase 2 SANRECO trial. William Blair declared the results “best-in-field” for PV.
Divesiran is designed to silence the TMPRSS6 gene, which is involved in the regulation of hepcidin that the body uses as a regulator of iron metabolism, Merck KGaA explained in the release. By increasing hepcidin levels, the drug limits iron availability for red blood cell production. This should reduce the need for frequent blood withdrawals that patients undergo as a form of treatment.
Also in SANRECO, divesiran resulted in 0.2 blood draws per patient as compared to 2.1 for those who received placebo through week 36.
Silence was also facing Takeda, which achieved approval for Mimrylo in PV this August. The Japanese company has forecast peak sales of $1-2 billion for the asset. William Blair said Merck KGaA appears to have gotten a bit of a deal given Silence also comes with a broader technology platform.
“The deal valuation does appear inexpensive considering Merck KGaA also gets the broader mRNAi GOLD siRNA platform as well,” the firm wrote. “However, this deal takes the execution risk off the table in an increasingly competitive space and delivers near-term shareholder value from what appears to be a competitive bid process.”
