What Scarlet Therapeutics does

Scarlet Therapeutics is a privately held, pre-clinical UK biotechnology company developing a proprietary platform that generates novel red blood cell-based therapeutics (tRBCs) for the treatment of serious diseases. The company's core technology revolves around the exclusive commercial licence to the BEL-A immortalised adult human erythroid cell line, originally developed at the University of Bristol and underpinning the ground-breaking RESTORE clinical study run by NHS Blood and Transplant and the University of Bristol. The platform genetically engineers RBC-producing cell lines to express and retain therapeutic proteins inside red blood cells, then differentiates them from a Product Master Cell Bank into universal, lab-grown RBCs designed to be administered regardless of donor blood type.

Scarlet organises its development pipeline around three application areas: Treat (long-acting therapeutic RBCs, with lead candidates targeting the rare metabolic diseases hyperammonemia and hyperoxaluria), Transfuse (universal off-the-shelf blood transfusion products), and Enhance (engineered RBCs intended to improve human performance). A May 2026 preclinical result demonstrated that the company's lab-grown universal red blood cells matured and circulated in vivo with a half-life comparable to normal donated red blood cells, validating the core manufacturing and biological approach.

The company is pre-revenue and funded by venture equity and non-dilutive grants. Disclosed capital raised includes an undisclosed seed round in May 2023 (led by Science Creates Ventures and Meltwind), nearly £1M of Innovate UK grant funding secured in 2023, and a £3.2M (approximately USD 4M) seed round closed on 7 May 2026 led by Eos Advisory with participation from SCVC, Oshen Bio, and Daft Capital. The intended commercial model is licensing/royalty arrangements and strategic partnerships with larger pharmaceutical companies for clinical development and commercialisation. The company operates from Bristol, United Kingdom, employs 1-10 staff, and is led by CEO Alistair Irvine alongside scientific co-founders Professor Ash Toye (CSO) and Professor Jan Frayne.

Name

Scarlet Therapeutics

Legal name

Scarlet Therapeutics Limited

Website

https://scarlet-tx.com

Company type

Private

Founded year

2022

Operating status

Operating

Headcount range

11–50 employees

Short description

Scarlet Therapeutics is a pre-clinical Bristol-based biotech developing a proprietary platform that generates lab-grown, universal red blood cells engineered with therapeutic proteins to treat rare metabolic diseases and other serious conditions.

Ownership category

akta.pro rank

Product category

Cell-Based Therapeutics

NAICS

Blood and Organ Banks (621991), Biological Product (except Diagnostic) Manufacturing (325414)

SIC

Biological Products, (No Disgnostic Substances) (2836)

akta.pro primary industry

Stem Cell Therapies (MSC/iPSC/HSC-derived) (HLAAABAE)

akta.pro secondary industries

Plasma-Derived Therapeutics (immunoglobulins, albumin, clotting factors) (HLAAAAAI), Blood Factors & Hemostasis Biologics (recombinant clotting factors, thrombolytics) (HLAAAAAL)

Keywords

• Cell-based therapeutics
• Red blood cell therapies
• Rare metabolic diseases
• Biopharmaceutical platform
• Cell line manufacturing

Headquarters

HQ city

Bristol

HQ country

United Kingdom

HQ region

Europe

Markets served

GTM type

B2B

Offering type

Hardware or Manufacturing

Cost components

Technology or R&D, Personnel, Operations, Others

Revenue model

1. Pre-revenue / R&D stage: Company is pre-clinical and pre-revenue, currently funded by seed equity (e.g., £3.2M round in May 2026) and non-dilutive grants. Long-term revenue model anticipated to be licensing/royalties and potential strategic partnerships with larger pharmaceutical companies for clinical development and commercialization.
2. Non-dilutive grant funding: Receives non-dilutive grant funding from Innovate UK / UKRI (e.g., nearly £1M awarded in 2023 through Innovate UK Investor Partnership and Engineering Biology grants) to advance R&D without equity dilution.

Go-to-market motion3 records

Core offering

Scarlet Therapeutics is developing a proprietary platform that generates novel red blood cell-based therapeutics (tRBCs) from immortalised erythroid cell lines rather than donated stem cells. The platform enables universal, lab-grown red blood cells engineered to express therapeutic proteins inside the cells, and underpins three application areas: Treat (long-acting therapeutic RBCs, with lead candidates in hyperammonemia and hyperoxaluria), Transfuse (universal off-the-shelf blood transfusion products) and Enhance (engineered RBCs for human performance).

Product overview

Scarlet Therapeutics is a single-platform biotechnology company whose core offering is a proprietary Therapeutic Red Blood Cell (tRBC) Platform built around the BEL-A cell line, which is held under exclusive commercial licence. The platform supports three complementary application areas: Treat (long-acting therapeutic RBCs/tRBCs engineered to treat disease, with lead candidates in hyperammonemia and hyperoxaluria), Transfuse (universal 'off-the-shelf' blood transfusion products), and Enhance (engineered RBCs designed to improve human performance). A Product Master Cell Bank anchors the scalable, 'biologic-like' manufacturing process that produces universal, lab-grown red blood cells administered regardless of blood type. Together these named products and modules form a unified modality in which the platform and licensed cell line underpin the indication-specific lead programs.

Differentiator

Problem solved

Functional benefit

Products and services

• Therapeutic Red Blood Cell (tRBC) Platform Proprietary platform that generates novel red blood cell-based therapeutics (tRBCs) from immortalised erythroid cell lines rather than donated stem cells. The platform genetically manipulates RBC-producing cell lines to express therapeutic proteins inside the RBCs, producing universal, lab-grown red blood cells compatible with most patients regardless of blood type, and supports a scalable, reproducible biologic-like manufacturing process. It is intended for pharmaceutical partners developing treatments for rare metabolic and other serious diseases.
• Hyperammonemia Program Lead therapeutic candidate built on the tRBC platform targeting hyperammonemia, a metabolic condition characterised by abnormally high levels of ammonia in the blood that can lead to brain injury or death, including urea cycle disorders and liver-related hyperammonemia. The candidate is designed as a long-acting RBC-based ammonia-clearing therapy dosed every 2–3 months.
• Hyperoxaluria Program Lead therapeutic candidate built on the tRBC platform targeting hyperoxaluria, a metabolic condition characterised by excessive oxalate in the blood and urine, including primary and secondary forms. The candidate is designed to be administered several times a year to maintain low oxalate levels and reduce recurrent kidney stones, kidney damage, and progression to renal failure.

Ideal customer profiles1 record

Technology focussed Yes

API detail

Has API

No

API docs

API detail

Core technology

AI maturity

App detail

Feature5 records

Recent moves6 records

Expansion highlights6 records

Direct peers

• Editas Medicine: Gene-editing company developing ex vivo edited cell therapies for sickle cell disease and other hematological indications; competes with Scarlet for investor attention in blood-cell-based therapeutic modalities and for large-pharma partnership interest.
• Rubius Therapeutics: Was the closest historical direct peer to Scarlet, developing engineered red blood cells (the RED PLATFORM) as therapeutics for rare diseases, enzyme deficiencies and cancer; the two companies share the same core modality of using modified RBCs as drug-delivery vehicles.
• Beam Therapeutics: Clinical-stage base-editing company developing in vivo and ex vivo gene-editing therapies for blood disorders including sickle cell disease and alpha-1 antitrypsin deficiency; comparable as a blood-cell-modality platform chasing rare-disease indications in the same scientific neighborhood as Scarlet.
• CRISPR Therapeutics: Develops ex vivo CRISPR gene-edited cell therapies including Casgevy, the first approved CRISPR-based therapy for sickle cell disease and beta thalassemia; directly comparable to Scarlet in targeting blood-cell-based modalities and competing for similar rare-disease hematology opportunities and partnerships.

Broad incumbents

• Alnylam Pharmaceuticals: Commercial-stage RNAi therapeutics leader with Oxlumo (lumasiran) approved for primary hyperoxaluria type 1; directly addresses one of Scarlet's two lead indications and represents both the incumbent competitor in hyperoxaluria and the type of large biotech that could partner with or acquire Scarlet's tRBC platform.
• Moderna: Large mRNA and protein-therapeutics platform company with growing rare-disease and cell-therapy ambitions; comparable as a broad biotech incumbent expanding into modality platforms relevant to rare metabolic and hematologic disease, and a potential partner for Scarlet's platform.
• Novo Nordisk: Global rare-disease leader with established enzyme-replacement and metabolic-disease franchises (relevant to hyperammonemia/urea cycle disorders); represents both an incumbent competitive threat and the archetype of large-pharma partner or acquirer for Scarlet's long-acting therapeutic RBC modality.
• Vertex Pharmaceuticals: Large biotech with Casgevy (sickle cell/beta-thalassemia) co-developed with CRISPR Therapeutics and a deep rare-disease pipeline; competes with Scarlet in adjacent hematology and rare-metabolic-disease end markets and represents a likely strategic partner or acquirer for blood-cell-based therapeutics platforms.

Emerging players

• Fate Therapeutics: Clinical-stage cell therapy company using engineered induced pluripotent stem cell (iPSC)-derived cell therapies including NK and T-cell candidates; adjacent modality that competes with Scarlet for capital and pharma partnership attention in engineered cell therapies.
• Century Therapeutics: Develops allogeneic iPSC-derived cell therapies for cancer and autoimmune diseases; comparable as a next-generation cell therapy platform pursuing similar pharma partnership outcomes and competing for the same deep-tech biotech investor pool as Scarlet.

Market position

Strengths5 records

Weaknesses5 records

Competitive moat4 records

Key risks5 records

Key highlights7 records

Customer concentration

• LinkedInuk.linkedin.com/company/scarlet-therapeutics

Compliance1 record

Revenue estimate

Valuation estimate

Number of profiles

Profiles7 records

Funding overview

Funding rounds2 records

Investors5 records

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M&A

Investments

M&A and investment is available on the Subscription and Enterprise plan.Contact sales →

Frequently asked questions about Scarlet Therapeutics