Bristol-based Scarlet Therapeutics has achieved a landmark preclinical result: its lab-grown, universal red blood cells (RBCs) have successfully matured and circulated in vivo, with a half-life comparable to donated blood.
This result is significant. Scarlet's RBCs are designed to be administered regardless of blood type — removing the donor-matching requirement that constrains conventional blood products, and opening the door to a single manufactured product that can serve a broad patient population.
Building on the milestone, Scarlet has closed a £3.2M seed round to advance its RBC platform, with initial focus on multiple metabolic diseases. Proceeds will support in vivo proof-of-concept studies, manufacturing development, and regulatory engagement.
The round was led by new investor Eos Advisory, with participation from SCVC, Science Creates' investment arm and Scarlet's investor since inception, alongside new investors Oshen Bio (Switzerland & Luxembourg) and Daft Capital (US). Three new Board appointments have also been confirmed: John Beadle (Eos Advisory), Didier Cowling (Oshen Bio), and Tim Sparey as independent Chair.
Scarlet's platform targets three application areas: therapeutic RBCs engineered to treat serious diseases; universal off-the-shelf transfusion products free from donor dependency; and next-generation RBCs designed to enhance human performance.
Alistair Irvine, CEO of Scarlet Therapeutics, said:
“Demonstrating that our lab-grown RBCs can mature and circulate in vivo – with a half-life matching donated blood – is a pivotal validation of what we’re building. Our proprietary cell line technology enables scalable, universal RBC manufacturing and opens the door to a new class of durable therapeutics and transfusion products. This financing puts us in a strong position to select our lead therapeutic candidate and move towards the clinic.”
Harry Destecroix, Managing Partner of SCVC, said:
"These results mark a major milestone for Scarlet — moving from concept to in vivo validation is a genuine inflection point. Scarlet has the science and the ambition to become a defining company in engineered red blood cells, and we're proud to continue backing that vision."
Scarlet Therapeutics is headquartered in Bristol within the Science Creates ecosystem. Its technology builds on pioneering research from the University of Bristol and ongoing clinical research through the RESTORE study — a first-in-human trial comparing the survival of lab-grown RBCs with donated blood.
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