Cytospire Therapeutics

Cytospire Therapeutics is a London-based biotechnology company developing a new class of cancer immunotherapies. The firm was founded in 2023 by Dr. Natalie Mount, a seasoned executive in the biotech sector with previous leadership roles at Adaptate Biotherapeutics and GammaDelta Therapeutics. Dr. Mount's experience includes leading Adaptate to a successful acquisition by Takeda, and her background includes a 16-year tenure at Pfizer before moving into smaller biotech firms.

The company's core focus is on its proprietary pan-gamma delta (γδ) T cell engager platform. This technology utilizes multispecific antibodies to act as a bridge, connecting the body's γδ T cells to tumor cells. Unlike conventional T cell engagers that activate CD3 T cells and can cause significant side effects by attacking healthy tissue, Cytospire's approach leverages the natural ability of γδ T cells to differentiate between cancerous and healthy cells. This is designed to create a more potent and safer therapeutic, minimizing toxicities like cytokine release syndrome and allowing for more effective treatment of solid tumors.

Cytospire's business model is centered on the discovery and development of this portfolio of multispecific engager antibodies. The company emerged from stealth in 2024 and secured an oversubscribed £61 million ($83 million) Series A financing in May 2026. The round was led by 4BIO Capital and included a syndicate of notable new and existing investors such as Servier Ventures, the British Business Bank, Abingworth, and LifeArc Ventures. This funding is intended to advance its lead program, CYT X300, through IND-enabling studies and into human clinical trials.

The lead candidate, CYT X300, targets EGFR (epidermal growth factor receptor), a well-validated antigen present in many solid tumors like colorectal, head and neck, and non-small cell lung cancers. By engaging all subtypes of γδ T cells—both those circulating in the blood and those residing within the tumor microenvironment—CYT X300 aims to generate broader and more effective anti-tumor responses. The company is positioning itself to address the significant unmet need in treating solid tumors where conventional T cell engagers have faced limitations.

Keywords: gamma delta T cell engagers, cancer immunotherapy, multispecific antibodies, solid tumors, immuno-oncology, Natalie Mount, CYT X300, EGFR targeting, biotherapeutics, pan-gamma delta, cell therapy, Abingworth, 4BIO Capital, Servier Ventures, preclinical studies, clinical trials, oncology, biotechnology, cancer treatment, tumor microenvironment