Can the thymus be drugged? TECregen raises $12 million to find out 

Swiss biotech TECregen has raised CHF 10 million ($12.56 million) in a seed round led by Boehringer Ingelheim Venture Fund to support the development of therapies targeting thymus regeneration. Alongside the financing, TECregen has appointed Bo Rode Hansen as chairman of its board.  

The Basel-based company is developing a new class of engineered biologics designed to rejuvenate thymic epithelial cells, “thymopoietics.” The goal is to restore immune function in conditions where thymic activity is compromised. While the thymus plays a central role in T-cell development, it has rarely been targeted directly by drugs, an underexplored area that TECregen is now aiming to address. 

Why target the thymus? 

Biotech rarely talks about the thymus because most immune drugs are designed to modulate what immune cells do in the periphery. But the thymus sits upstream of that. It is where T cells mature and where the immune system learns to respond to foreign threats. This happens through positive and negative selection in a microenvironment built largely by thymic epithelial cells (TECs), including medullary TECs that help enforce central tolerance through programs such as AIRE-driven expression of tissue antigens. 

With age, the thymus undergoes a gradual loss of thymic tissue and function that contributes to lower production of new naïve T cells and, over time, a less diverse T-cell receptor repertoire. In parallel, the thymus is also vulnerable to iatrogenic injury.  

So, the most obvious reason to revisit the thymus is immune rebuilding after immune-depleting treatments. In settings like chemotherapy, radiation, and hematopoietic cell transplantation, patients can be left with prolonged T-cell lymphopenia even after other blood counts recover. Reviews focused on “T cell regeneration after immunological injury” repeatedly come back to the same bottleneck: restoring thymic function is one of the few routes to re-establishing a diverse pool of newly generated naïve T cells, rather than just expanding what is already there. 

There is also a more direct disease logic. Some patients have thymic defects where the organ is absent or non-functional, leading to severe T-cell immunodeficiency. And then there is autoimmunity. When central tolerance mechanisms in the thymus fail, self-reactive T cells can escape into circulation and contribute to autoimmune disease. In myasthenia gravis, thymic abnormalities are common, and thymectomy has evidence of benefit in defined patient groups. 

Zoom in: TECregen’s approach

TECregen is framing thymus regeneration as an upstream way to rebuild immune capacity. Instead of trying to stimulate or suppress immune cells in the periphery, the company is going after the thymus’ “support system”, TECs, which shape the microenvironments that allow T cells to develop and be selected properly. 

What the company has publicly disclosed so far is the broad blueprint, not the lead drug. “TECregen is engineering a new class of biologics, thymopoietics, designed to regenerate the thymus, the only organ capable of producing newly functional naïve T cells,” said the company’s newly appointed chairman, Bo Rode Hansen. 

“With age, thymic involution is a primary driver of immune decline. Importantly, lymphoid progenitors in older individuals remain largely intact, indicating that immune aging is driven not by a lack of progenitors but by dysfunction of the thymic microenvironment. This positions thymic epithelial cells as the critical bottleneck. By restoring thymic function at its source, thymic regeneration has the potential to re-establish durable, endogenous immune competence, which cell supplementation alone cannot achieve.” 

What remains unclear, and what will matter most for judging how promising this is, are the specifics: the identity of the lead molecule(s), the delivery strategy in practice, the first clinical setting, and any timeline toward IND-enabling work or first-in-human studies. TECregen has not yet disclosed a lead asset or a clinical timeline in its public materials, so it is fair to say it is still too early to predict TECregen’s trajectory. 

Looking forward, Rode Hansen said the key challenges are achieving precise and durable regeneration of the thymic epithelium while ensuring safety and translatability, particularly in aging populations. 

A previous attempt to leverage thymus biology: Smart Immune 

One reason the thymus rarely shows up in biotech coverage is that it is not an easy organ to drug. But there have been attempts to build clinical programs around it; one of the more visible European examples was France’s Smart Immune. 

Smart Immune’s bet was different from TECregen’s. Rather than trying to regenerate the thymus itself, Smart Immune developed SMART101, a cell therapy made of donor-derived T-lymphoid progenitors. Once infused, these progenitors would migrate to the patient’s thymus and complete their maturation there, undergoing positive and negative selection to generate a polyclonal repertoire of educated naïve T cells more quickly. In this strategy, the thymus is not the drug target, but it is a part of the mechanism. 

In settings like hematopoietic stem cell transplantation, immune reconstitution can lag, and delayed T-cell recovery is a real clinical vulnerability. Smart Immune pushed its platform into phase 1/2 testing in patients receiving transplants in hematologic malignancies. Early reports have suggested an encouraging initial safety profile in small numbers of treated patients.  

There is also a messier part of the story that brought Smart Immune back into the headlines more recently. In 2025, Smart Immune entered court-supervised proceedings in Paris, with legal notices documenting an opening of restructuring (redressement judiciaire) followed by liquidation judiciaire and a search for a buyer/cession process. In other words, even with clinical programs underway and high-profile support earlier in its life, including an investment from the Gates Foundation in 2023, the company still ran into the kind of financing wall that is common for capital-intensive cell therapy developers, especially in a tougher funding market. 

In TECregen’s story, Smart Immune serves less as a competitor than as a reality check. The thymus remains an attractive lever for rebuilding immune capacity, and there is credible science behind thymus-dependent strategies. But turning that biology into a sustainable product and company, with clear endpoints, scalable manufacturing, and enough capital to cross clinical inflection points, has proven difficult. 

“Previous efforts, including those by Smart Immune, rightly recognized the thymus as a critical site for immune cell maturation and focused on directing progenitors to the organ. While valuable, these approaches do not address the fundamental driver of immune aging: thymic involution itself. TECregen’s strategy is distinctly different. We directly target the thymic epithelium with thymopoietics designed to regenerate thymic structure and function, enabling sustained production of naïve T cells and durable immune fitness,” explained Rode Hansen. 

Zooming out: where thymus regeneration fits 

If thymus regeneration is becoming a space, it is still a small one, and the product formats are very different. At one end are tissue- and transplant-based interventions aimed at the most clear-cut thymus failures. The best example is RETHYMIC, a processed allogeneic thymus tissue product approved in the U.S. for congenital athymia, where patients are essentially born without a functional thymus.  

A second cluster is cell therapy and organoid engineering, where the goal is to recreate thymic function using stem-cell-derived thymic cells. Thymmune Therapeutics, for example, is developing iPSC-derived thymic cells designed to reconstitute thymus activity in settings such as immunodeficiency and post-transplant immune recovery. Tolerance Bio is pursuing a related strategy, combining allogeneic iPSC-derived thymic tissue with pharmacological approaches, and has reported preclinical data showing that implanted thymic organoids can support T-cell development in vivo. 

This is the landscape TECregen would sit alongside, but with a different bet. Based on what it has disclosed so far, TECregen is pursuing novel biologics aimed at rejuvenating TECs, rather than supplying thymic tissue or cells. If that approach works, it could, in principle, complement other immune strategies that depend on a healthy pipeline of new T cells, for example, helping patients reconstitute immunity after treatment.