Hansoh Pharma Exits $1.3B Collaboration, Delaying Silence Therapeutics’ Phase III Cardiovascular Drug Trial
Hansoh Pharma
Pharmaceutical Research, Production, and Sales
News on February 27, 2025: A notable development has emerged in the biotechnology sector as Hansoh Pharma decided to withdraw from a collaboration project valued at up to $1.3 billion. This move has forced Silence Therapeutics, a UK-based biotech company, to slow down its Phase III clinical trial plans for a cardiovascular disease drug. Behind this change lies a complex landscape of research and development alongside commercial partnerships, significantly impacting both companies and the broader industry.
Silence Therapeutics has long been dedicated to the research and development of innovative drugs. Its developed zerlasiran is an siRNA therapy for treating atherosclerotic cardiovascular diseases, with a mechanism of action that achieves therapeutic effects by "silencing" the LPA gene. At the American Heart Association (AHA) conference in November last year, the company announced impressive Phase II clinical trial data for zerlasiran: during the 36-week trial period, after placebo adjustment, patients' lipoprotein(a) (Lp(a)) levels decreased by 80% compared to baseline. At that time, the executives of this London-based biotechnology company were highly confident, believing that these data laid a solid foundation for advancing zerlasiran into Phase III clinical trials and also helped determine the optimal dose for the Phase III trial.
However, just three months later, the situation changed. In the Q4 financial report released on February 27, Silence CEO Craig Tooman revealed: "Although we remain confident in the zerlasiran program for treating high Lp(a), the Phase III cardiovascular outcomes study will only be initiated after securing a partnership." Currently, Silence is in discussions with potential partners and is actively advancing its core work, aiming to bring the zerlasiran program to meet the standards for entering Phase III trials in the first half of 2025.
Silence CFO Rhonda Hellums elaborated on the company's financial considerations in the same earnings report: "As of the end of last year, the company held more than $147 million in cash, cash equivalents, and short-term investments. The decision to temporarily not initiate the Phase III study of zerlasiran without a partner extends the company’s cash runway to 2027, providing us with greater financial flexibility to invest in innovative R&D pipelines while we continue to seek partnership opportunities for this program."
In Silence's R&D pipeline, divesiran is a highly anticipated product. This is another gene silencing therapy drug currently in Phase II trials for patients with polycythemia vera (PV), a rare blood cancer. Silence CEO Tooman stated that in 2025, the company will focus its investments on R&D projects targeting rare diseases, aiming to meet unmet medical needs in these areas with first-class siRNA therapies. Divesiran is a strong testament to this strategy and clinical commitment.
The root of Silence Therapeutics' strategic adjustments lies in Hansoh Pharma's withdrawal from the collaboration. In 2021, Hansoh Pharma paid Silence an upfront fee of $16 million to kick off the partnership, leveraging Silence’s mRNAi GOLD platform to develop therapies targeting three undisclosed preclinical targets. However, on February 27, Silence revealed that Hansoh Pharma had "decided not to proceed with the related research and development."
Currently, there is no official clarification on the specific reasons for Hansoh Pharma's withdrawal from the collaboration. It is speculated that the decision was primarily based on dual considerations of research and development (R&D) costs and market competition. On one hand, during the progress of the collaboration, the R&D costs far exceeded expectations. Developing therapies using the mRNAi GOLD platform involves complex technical processes, from gene target screening and RNA interference mechanism optimization to drug formulation development, each step requiring substantial financial investment. Moreover, during the clinical trial phase, the high standards for trial data and the strict monitoring measures implemented to ensure safety and efficacy have driven up R&D costs. As the research progressed, Hansoh Pharma realized that, at the current rate of expenditure, a massive amount of additional funding would be required to sustain the project, creating significant financial pressure on the company.
On the other hand, the intensification of market competition is also an important factor. During the period of cooperation, the fields of cardiovascular diseases and related gene therapies have developed rapidly, with numerous pharmaceutical companies increasing their R&D investments, making market competition even fiercer. New treatment methods and drugs have continuously emerged, and some competitors have already launched products with similar mechanisms of action, capturing a certain market share. After evaluation, Hansoh Pharma concluded that even if the R&D of the cooperative project were completed, the competitiveness of its product in the market might still be limited, making it difficult to achieve sufficient market returns to cover the substantial initial investment. Based on comprehensive considerations of cost-effectiveness and market prospects, the company ultimately decided to withdraw from the collaboration.
From the industry perspective, this incident fully highlights the high risks associated with biopharmaceutical R&D collaborations. For Silence, losing Hansoh Pharma as a partner means forfeiting potential gains of up to $1.3 billion. The pressing challenge now is how to advance its R&D pipeline and seek new partners with limited funding. This event also serves as a wake-up call for other biopharmaceutical companies: when engaging in collaborative R&D, it is crucial to comprehensively assess risks, and strategically plan R&D pathways and funding arrangements. Only then can companies navigate steadily through the complex and ever-changing industry landscape.
