CYT X300

CYT X300 is Cytospire's lead clinical asset, described as a first-in-class PAN-gamma delta T cell engager for the treatment of solid tumours. The programme was the clinical centrepiece of Cytospire's £61m Series A in May 2026, drawing investors including Abingworth, Servier Ventures, LifeArc Ventures, Sound Bioventures, and Medical Incubator Japan.

Gamma delta T cells are a subset of T cells that recognise tumour-associated antigens through both innate and adaptive immune mechanisms. Unlike conventional alpha-beta T cell therapies (such as CAR-T), gamma delta approaches are not restricted by HLA type, making them potentially applicable across a broader patient population and for solid tumours where CAR-T has historically struggled. A 'PAN' gamma delta engager means CYT X300 aims to recruit multiple gamma delta T cell subtypes simultaneously, increasing the breadth of tumour cell killing. The 'first-in-class' designation reflects that no approved PAN-gamma delta engager existed at the time of Cytospire's Series A. The round will fund Phase I clinical trials for CYT X300.