Company Description
Silence Therapeutics plc (Nasdaq: SLN) is a global clinical-stage biotechnology company that develops novel therapies based on short interfering RNA (siRNA). Through its proprietary mRNAi GOLD™ platform, the company designs precision engineered siRNAs intended to selectively target and silence disease-associated genes in the liver. According to its public disclosures, Silence focuses on areas of high unmet medical need with programs advancing in cardiovascular disease, hematology and rare diseases.
Business focus and technology
Silence Therapeutics describes itself as being committed to transforming people’s lives by silencing diseases using proprietary siRNA technology. The company’s mRNAi GOLD platform is used to create siRNA product candidates for its wholly owned pipeline as well as for out-licensed programs with third-party collaborators. Its approach centers on targeting genes expressed in the liver, which the company characterizes as a substantial opportunity for siRNA-based medicines.
The company’s disclosures highlight that its siRNAs are designed to precisely target and silence genes in liver cells. This focus underpins programs in hematology, cardiovascular disease and rare conditions where liver-expressed targets play a central role in disease biology.
Pipeline and key programs
Based on the information provided, Silence Therapeutics has a wholly owned pipeline focused on three therapeutic areas: cardiovascular disease, hematology and rare diseases. Product candidates mentioned in its materials include:
- Divesiran (SLN124), described as a siRNA product candidate with the potential to treat several hematological disorders. More recent company communications emphasize divesiran as a first-in-class siRNA for polycythemia vera (PV), a rare myeloproliferative neoplasm characterized by excessive production of red blood cells and elevated hematocrit levels.
- Zerlasiran (SLN360), which the company identifies as being developed as a potential treatment to reduce cardiovascular issues.
- SLN-312, an siRNA product candidate that the company has licensed to AstraZeneca, with a Phase 1 study described as ongoing.
- SLN-548, a wholly owned siRNA for complement-mediated diseases, which the company has stated it has decided to pause initiating a Phase 1 study for while it prioritizes extra-hepatic activities.
In its recent communications, Silence places particular emphasis on divesiran for PV. The company reports that divesiran is developed from its mRNAi GOLD platform and is designed to selectively target and silence TMPRSS6, a negative regulator of hepcidin, which it calls the body’s master regulator of iron metabolism. By increasing hepcidin levels, divesiran aims to redirect iron delivery away from the bone marrow, lower red blood cell production and potentially reduce the high red blood cell count in people living with PV.
Clinical development activities
Silence Therapeutics describes itself as a clinical-stage company, with multiple ongoing clinical programs. For PV, the company reports:
- A SANRECO Phase 1 study of divesiran in phlebotomy-dependent PV patients, with updated data presented at the European Hematology Association (EHA) Annual Congress. The company states that these data showed durable hematocrit control to target levels (≤45%), an essentially eliminated need for therapeutic phlebotomies in the targeted population, increases in hepcidin and ferritin and a favorable tolerability profile with no dose-limiting toxicities.
- A SANRECO Phase 2 study of divesiran in PV, described as a global, randomized, double-blind, placebo-controlled trial evaluating two dosing intervals (every six weeks and every twelve weeks) in 48 phlebotomy-dependent PV patients. The primary endpoint is the proportion of patients receiving divesiran compared to placebo who maintain hematocrit levels below 45% without phlebotomies between specified weeks. Secondary endpoints include safety and tolerability, pharmacokinetics and quality of life measures. The company has announced completion of Phase 2 enrollment.
Silence also reports that divesiran has received FDA Fast Track and Orphan Drug designations for PV. In cardiovascular disease, the company indicates that it has completed core Phase 3 readiness activities for zerlasiran, including manufacturing and supply scale up, and that it is in dialogue with potential partners regarding Phase 3 development and potential future commercialization.
Beyond liver-directed programs, Silence notes that it is advancing extra-hepatic cell targeting of siRNA, where it reports promising initial preclinical activity in mouse models. As part of prioritizing these extra-hepatic activities and its core PV program, the company has stated that it paused initiating a Phase 1 study of SLN548.
Collaborations and partnerships
The company discloses that it has out-licensed programs with third-party collaborators. A specific example mentioned is SLN312, for which a Phase 1 study is described as ongoing under a license agreement with AstraZeneca. This collaborative model complements its wholly owned pipeline in hematology, cardiovascular disease and rare diseases.
Corporate and listing information
Silence Therapeutics plc is organized under the laws of England and Wales. The company reports that its American Depositary Shares (ADSs), each representing three ordinary shares with nominal value £0.05 per share, trade on The Nasdaq Stock Market LLC under the symbol SLN. Its ordinary shares are also listed on Nasdaq in connection with the ADS listing. Company filings list London, United Kingdom as the location of its principal offices.
The company has communicated that it has delisted from the London Stock Exchange to become solely listed on Nasdaq and has transitioned to being a U.S. domestic issuer. It also reports holding annual general meetings of shareholders and describes typical governance matters such as director re-appointments, auditor appointments and advisory votes on executive compensation.
Leadership and governance developments
In its SEC filings and press releases, Silence Therapeutics has reported several governance and leadership changes. These include:
- Changes to the composition of its Board of Directors, such as the appointment of new directors and the retirement or resignation of others.
- A report that its then President and Chief Executive Officer agreed by mutual consent to end his employment and step down from the Board, with the Chairman of the Board appointed as interim principal executive officer.
- Board-level committee adjustments and shareholder voting outcomes on director re-appointments and other resolutions at its annual general meeting.
These disclosures provide investors with insight into the company’s oversight structure and corporate decision-making processes.
Regulatory and financial reporting
Silence Therapeutics files periodic and current reports with the U.S. Securities and Exchange Commission, including Forms 10-K, 10-Q and 8-K. In recent filings, the company has discussed its research and development expenses, general and administrative costs, net losses, cash and short-term investment balances, and expectations regarding its cash runway. It also references risk factors related to its history of net operating losses, the early stage of clinical development of its product candidates, regulatory approval processes, reliance on third-party suppliers and manufacturers, collaboration outcomes and intellectual property protection.
Through these filings and accompanying press releases, Silence provides quantitative and qualitative information about its operations, clinical progress and financial condition, while noting that forward-looking statements are subject to risks and uncertainties.
Position within the biotechnology and pharmaceutical landscape
Within the broader pharmaceutical preparation manufacturing and biotechnology sector, Silence Therapeutics distinguishes itself by its explicit focus on siRNA-based medicines targeting liver-expressed genes. Its programs in PV, cardiovascular disease, hematology and rare diseases are all tied to this platform-based approach. The company’s communications emphasize areas of high unmet medical need and the potential for siRNA technology to address disease mechanisms at the genetic level in liver cells.
For investors and observers, the SLN stock overview therefore centers on a clinical-stage biotech that combines a proprietary siRNA platform, a focused pipeline in hematology and cardiovascular disease, collaborations with larger pharmaceutical companies and an exclusive Nasdaq listing structure using American Depositary Shares.