Genewity, a Leiden-area gene therapy company, set out to build i-Thymus: thymus tissue grown from a patient's own induced pluripotent stem cells with the help of a gene-therapy vector, to be implanted in babies born without a thymus, who cannot make T-cells and rarely survive beyond the age of three. It was selected in the EIC Accelerator's March 2023 cut-off and received an EU grant of €2.50 million for i-THYMUS, a €3.57 million project that ran from November 2023 to October 2025, according to CORDIS. The objective was to "finalise development to enter the clinic for a Phase I/II trial" and reach the EU market with a pharma partner by 2028.
After the first year, the only public report said protocols had been refined towards GMP standards, the gene-therapy vector improved and a humanised mouse model set up to test whether i-Thymus produces human T-cells, according to the CORDIS reporting page. In a post on the completed project, Genewity says it made "large steps to GMP-readiness", including a validated GMP vector manufacturing process, but that "the program encountered scientific challenges associated with pioneering innovation", according to Genewity. The thymus programme is not mentioned elsewhere on its website.
Company file
- Legal entity
- Genewity B.V., Leiden; parent Genewity Holding B.V., Oegstgeest
- Subsidiary
- Videja B.V., runs the RAG1-SCID trial
- EIC programme
- i-Thymus, iPSC-derived thymus organoids
- Lead programme
- Stem cell gene therapy for RAG1-SCID
- Trial status
- NCT04797260, suspended, updated July 2026
- Accounts
- Not available in free sources
- EIC funding
- Grant first
Where Genewity Stands Now
Genewity's website now presents it as a developer of stem cell gene therapies for rare childhood diseases, with a clinical-stage programme for RAG1-deficient severe combined immunodeficiency run by its subsidiary Videja, and calls early results "highly encouraging". That trial, which started in 2021 at Leiden University Medical Center and sites in Poland, Spain and Turkey, is suspended: the registry says recruitment is on hold "as a result of a reported SAE for one of the patients", with safety data being evaluated for a link to the treatment, according to ClinicalTrials.gov.
"Although the program encountered scientific challenges associated with pioneering innovation, the capabilities, insights, and experience gained through i-THYMUS continue to shape Genewity's research strategy and future development programs."
Genewity, on the completed EIC projectThe Technology: Building an Organ From Stem Cells
The thymus is where immature immune cells learn to become T-cells. Children with complete DiGeorge syndrome are born without one. The only treatment, transplantation of donor thymus tissue, is sold commercially only in the US, costs more than €2.5 million per patient and carries about 30% mortality, the company says. i-Thymus would guide the child's own reprogrammed stem cells through the embryonic steps that form a thymus. Genewity itself describes the work as pioneering.
What the EIC Award Promised, and What the Record Shows
The award promised to complete preclinical development and prepare a first clinical trial. The company built manufacturing capability and a stronger team, as it describes. It does not claim to have reached clinical readiness, and no i-Thymus trial has been registered. No final report with the preclinical results is public.
- GMP vector manufacturingDeliveredValidated, per company.
- GMP-ready thymus protocolPartial"Large steps", not complete.
- Efficacy in mouse modelUnverifiedResults not published.
- Clinical trial readinessNot reachedScientific challenges.
The Money
The EU paid 70% of the project. Genewity's website announces no private funding round, and its finances are not public in free sources. The grant supported infrastructure and staff the company says it still uses, but the product it was meant to advance is no longer promoted.
What Cannot Be Checked
Questions for the EIC
What the scientific challenges were, whether the humanised mouse studies showed T-cell development, whether i-Thymus has been stopped, and why no final report is public are not public.
Why Europe Should Care
High-risk science sometimes fails, and the EIC Accelerator exists to take such risks. Genewity is unusually open about its setback. The public still deserves to know what the €2.50 million taught, so that others working on thymus regeneration can learn from it.
What the award promised
Preclinical completion of an engineered thymus and readiness for a Phase I/II trial.
What the record shows
GMP vector manufacturing, scientific challenges and no clinical trial.
The Verdict
A risk that did not pay off
Genewity built capabilities with EIC money, but the engineered thymus did not reach the clinic. The details of why have not been published.
Genewity and the EIC have not been asked for comment for this article. It is based entirely on public records and published statements, linked throughout.
