Cytospire Therapeutics raises £61m to advance pan-gamma delta T cell first-in-human trials
This article covers Cytospire Therapeutics, a biotech startup, raising £61m in a series A funding round led by 4BIO Capital to advance a pipeline of pan-gamma delta T cell engagers, including lead programme CYT X300, toward first-in-human testing in EGFR-positive solid tumours. The funding will support IND-enabling preclinical studies, GMP manufacturing and preparations for a first-in-human clinical trial targeting colorectal, head and neck and non-small cell lung cancers.
Cytospire Therapeutics, a biotech startup, has raised £61 million in a series A funding round led by 4BIO Capital to advance a pipeline of pan-gamma delta T cell engagers, including lead programme CYT X300, toward first-in-human testing in EGFR-positive solid tumours. The size and composition of the syndicate signal continuing investor interest in next-generation immune cell engagers for difficult-to-treat cancers.
Why it matters
The deal matters because it targets a recognised limitation of existing T cell engager therapies. Conventional CD3-directed engagers can face trade-offs between efficacy and safety, and their performance can be inconsistent across patients. Cytospire’s approach is to engage gamma delta T cells — a less conventional arm of the immune system that preclinical and translational data suggest can contribute to anti-tumour responses — attempting broader activation across tissue-resident and blood-resident effector cells. If the biology translates in humans, the platform could offer an alternative route to harnessing the immune system against solid tumours where outcomes have been mixed.
Inside the product
Cytospire is developing differentiated multispecific immune cell engager antibodies engineered to direct and enhance the activity of gamma delta T cells. Its lead candidate, CYT X300, is designed as a pan-gamma delta T cell engager that targets all gamma delta T cells rather than specific subtypes — an explicit strategy to reduce patient heterogeneity in response.
The company says proceeds will support IND-enabling preclinical studies, GMP manufacturing and preparations for a first-in-human clinical trial of CYT X300 in EGFR-positive solid tumours, including colorectal, head and neck and non-small cell lung cancers. That places the programme at the late preclinical / translational stage, with a clinical readout some years away if regulatory and safety milestones are met.
Who are the investors?
The £61 million round was led by 4BIO Capital and included participation from Servier Ventures, British Business Bank, Sound Bioventures, Criteria Bio Ventures, Abingworth, LifeArc Ventures, Modi Ventures, Medical Incubator Japan and Pathway Bioventures. The syndicate mixes specialist life sciences VC, corporate venture capital and public funding support, reflecting both commercial and strategic interest in novel immunotherapy modalities.
In the announcement, Owen Smith, Partner at 4BIO Capital, said:
Cancer immunotherapy has provided a step-change in treatment for many types of cancer over the past decade, but we need to do more. We are proud to have led the Series A alongside this strong investor syndicate. It is exciting to see the company advance CYT X300 and its pioneering portfolio of cancer therapies into the clinic to improve outcomes for cancer patients.
In the announcement, Bali Muralidhar, Investor at Abingworth, said:
As the founding investor in Cytospire, we are strong believers in the potential of gamma delta T cell-based therapies to change the treatment paradigm in multiple cancer indications. There is a need for novel strategies in the field of immune cell engagers, and we believe that Cytospire is well positioned at the forefront of this exciting space.
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Founder perspective
In the announcement, Natalie Mount, CEO at Cytospire Therapeutics, said:
We are excited to write the next chapter of Cytospire’s story with this fantastic group of specialist investors. Immune cell engagers are an important type of cancer immunotherapy, but we know that there are significant limitations from both an efficacy and safety perspective with conventional CD3 T cell engagers. We are building on the growing body of translational and clinical data showing gamma delta T cells are critical components of the anti-cancer immune response, with biology ideally suited to novel cell engagers. The significant fundraise that we are announcing today reflects the quality of our team and our science, and the huge potential of our pan-gamma delta T cell engagers.
The bigger picture
The round reinforces ongoing momentum in UK biotech for immuno-oncology approaches that move beyond established checkpoint inhibitors and CD3 engagers. Public and private backers — here represented by the British Business Bank alongside specialist life sciences investors and corporate VC — continue to deploy capital into translational programmes with clear paths to the clinic. For the wider European ecosystem, the deal highlights appetite for platform approaches that aim to address patient heterogeneity in solid tumours.
This financing adds to a steady flow of capital into UK biotech and could help attract further interest in gamma delta T cell-based therapies across Europe as programmes progress toward human data.
They've invested in Cytospire Therapeutics
Get to know these biotech investors
| Investor | Sector | Stage | Activity | Team | Connect |
|---|---|---|---|---|---|
 4BIO Capital | 3 investments investments | 7 contacts contacts | |||
 Servier Ventures | 1 investment investment | more info | |||
 British Business Bank | 76 investments investments | 7 contacts contacts | |||
 Sound Bioventures | 2 investments investments | more info | |||
 Criteria Bio Ventures | 2 investments investments | more info | |||
 Abingworth | 3 investments investments | more info | |||
 LifeArc Ventures | 3 investments investments | 6 contacts contacts | |||
 Modi Ventures | 4 investments investments | more info | |||
 Pathway Bioventures | 1 investment investment | more info |
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