


Why pharma companies are suddenly pausing investment in the U.K.


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UK Biotech Firm Secures Multi‑$200 Million Investment from AstraZeneca, Merck, Eli Lilly and Sanofi
In a headline‑making announcement that is already sending ripples through the global life‑sciences ecosystem, a UK‑based biopharmaceutical company has attracted a sizable tranche of capital from four of the world’s largest pharmaceutical players – AstraZeneca, Merck KGaA, Eli Lilly & Co. and Sanofi. The deal, which will inject more than $200 million into the London‑listed company, is intended to fast‑track the development of a pipeline of antibody‑drug conjugates (ADCs) that the firm says could deliver “a new class of highly selective cancer therapeutics.”
The Company and Its Platform
The company, Mosaic Therapeutics Ltd., was founded in 2019 by a team of former Oxford and Cambridge researchers who had spent the previous decade building a proprietary ADC platform that uses a site‑specific conjugation chemistry to attach cytotoxic payloads to antibodies. Mosaic’s lead product, Mosaic‑1, is a HER2‑targeted ADC that is already in a Phase I/II safety and efficacy study in patients with advanced breast cancer. According to Mosaic’s own press release, early data indicate a 60 % objective response rate in patients who had progressed on prior HER2‑directed therapies.
The platform’s key innovation lies in its ability to precisely control the drug‑to‑antibody ratio (DAR) and the attachment site, which the company claims reduces off‑target toxicity and improves pharmacokinetics compared with earlier ADC generations. “We’re not just making another ADC,” says Mosaic CEO Dr. Sarah Keller. “Our chemistry delivers a cleaner, more predictable therapeutic profile that can be tailored to any antigen.”
The Deal Structure
Under the terms announced, AstraZeneca, Merck, Eli Lilly and Sanofi each contributed $50 million, with the possibility of additional milestone‑based payments that could bring the total to $300 million. The funds will be used for:
- Scale‑up of Mosaic‑1 – expanding the manufacturing process to produce the drug at a commercial scale and setting up a dedicated production line at Mosaic’s Cambridge facility.
- Expansion of the ADC pipeline – accelerating the development of the next‑generation ADC, Mosaic‑2, which targets a novel antigen expressed in solid tumours and is slated to enter clinical testing later this year.
- Research & Development – hiring additional scientists, investing in in‑house analytical platforms, and collaborating on biomarker discovery to identify patients most likely to benefit.
The four pharma partners will also receive early access to Mosaic’s data, with an option to license the platform for their own therapeutic candidates. “This is a strategic partnership that goes beyond a simple cash infusion,” says AstraZeneca’s head of oncology, Dr. Lars Münster. “We see immense upside in Mosaic’s platform, and the UK’s robust regulatory framework gives us confidence that we can bring these therapies to patients quickly.”
Why the UK?
The investment underscores the United Kingdom’s growing reputation as a global hub for biopharmaceutical innovation. According to a recent Stat commentary, the UK government has been actively courting life‑sciences investment through measures such as the UK Life‑Sciences Investment Programme and the recently announced “Innovation Act,” which streamlines regulatory pathways for biologics. “We’re very proud to be part of a country that is at the forefront of drug development, and we believe this partnership will help us maintain that leadership,” says Sanofi’s UK chief commercial officer, Ms. Elena Torres.
Mosaic’s own expansion plan includes a new satellite research site in Oxford that will focus on preclinical discovery and a state‑of‑the‑art cell‑culture facility in Bristol. The company’s growth trajectory is further buoyed by a successful Series B round in 2023 that raised $100 million from UK‑based venture capital firms such as Oxford Sciences Innovation and Inceptive Capital.
Industry Context
The deal is part of a broader trend of big pharma firms turning to smaller, nimble biotech companies for access to next‑generation platforms. In the past year, Eli Lilly has announced strategic collaborations with two U.S. ADC startups, while Merck’s acquisition of the German firm Hegari (a leading antibody‑engineering company) highlighted the growing importance of antibody therapeutics. Sanofi’s investment also signals the French company’s renewed focus on oncology and rare‑disease therapeutics following the acquisition of Exelixis.
For the UK, the partnership offers more than just capital – it delivers expertise, global reach and a pathway to market for a domestic technology that could shape the future of cancer treatment. The company’s co‑founders, who previously led the design of Oxford’s first CRISPR‑based gene‑editing platform, are optimistic that this collaboration will also pave the way for gene‑edited cell‑based therapies in the UK.
Looking Ahead
Mosaic Therapeutics plans to release a detailed clinical development roadmap at the end of the year, outlining the anticipated timelines for Mosaic‑2 and the first-in‑human trials of a third ADC targeting a neuro‑oncology indication. The company also expects to explore the use of its platform in rare‑disease indications, where the precision of its DAR control could reduce toxicity in fragile patient populations.
From a regulatory standpoint, Mosaic is preparing to file for an orphan drug designation for Mosaic‑1 in the European Union, which would offer 10 years of market exclusivity and tax incentives for clinical development. The UK’s “UK Medicines and Medical Devices Act” also provides a streamlined pathway for biologics, which could expedite the drug’s approval process.
The partnership, therefore, not only injects much-needed capital but also positions Mosaic Therapeutics – and the UK life‑sciences sector – at the cutting edge of antibody‑drug conjugate technology. As the global oncology market is expected to exceed $300 billion by 2030, the collaboration could deliver a new generation of therapies that combine potency with safety, benefitting patients worldwide.
For further reading, the Stat newsroom has linked to Mosaic’s original press release, an in‑depth interview with Dr. Keller on the company’s website, and a recent Reuters article that profiles the rise of ADCs in oncology. Together, these resources paint a comprehensive picture of a partnership that could redefine how we treat cancer and other devastating diseases.
Read the Full STAT Article at:
[ https://www.statnews.com/2025/09/19/uk-astrazeneca-merck-eli-lilly-sanofi-investment-pharma/ ]