Quell Therapeutics: reducing the burden of lifelong immunosuppression for transplant patients

Problem to be solved

Transplant recipients and people with autoimmune diseases often rely on systemic immunosuppressant drugs that can have serious long-term side effects, including increased infection risk and cancer. There is a need for therapies that restore immune balance more precisely-suppressing harmful immune responses while preserving wider immune function-so patients can achieve durable benefit with fewer complications.

Solution

Quell Therapeutics develops engineered regulatory T-cell (Treg) therapies designed to create targeted immune tolerance. By directing Tregs to specific tissues and adding features such as phenotype stabilisation and safety controls, the platform aims to provide single-dose treatments that can reduce or replace the need for lifelong systemic immunosuppression. Initial programmes focus on liver transplant, alongside expansion into conditions such as ALS and Type 1 diabetes.

How UCL Ventures helped

Quell was founded by Syncona and leading academics from UCL, King’s College London and Hannover Medical School. UCL Ventures supported the formation of the company by helping to structure and negotiate the licensing and collaboration arrangements needed across multiple institutions, enabling the team to bring the science together into a single venture positioned for investment and clinical translation.

Dr Barny Cox, Senior Business Manager for UCL Ventures, and previously a board member at Quell, explains: “The company benefits from the expertise of some of the world’s leading immunologists. Working collaboratively across multiple organisations made the task of formalising the contracts required for company incorporation all the more complex. All parties involved were driven by a united desire to rapidly progress these innovative treatments towards the clinic for the benefit of patients.”

Where is Quell Therapeutics now?

Quell has attracted significant investment to build its platform and pipeline, including a Series A financing announced in 2019 and extended in 2021, bringing total investment to $84m. The company has grown rapidly, creating high-skilled roles while preparing its first programmes for clinical evaluation. Next, Quell is focused on progressing engineered Treg therapies into and through clinical trials, while expanding into additional indications where restoring immune balance could transform patient outcomes.

 Quell Therapeutics has been advancing its engineered regulatory T‑cell (CAR‑Treg) platform into first‑in‑human testing with the CHILL Phase 1/2 study of QEL‑005 in rheumatoid arthritis and systemic sclerosis following UK regulatory approval, and reported supporting clinical and translational data from its LIBERATE program that show engineered Tregs can persist, traffic to target tissues and remain functionally stable for over a year.

Early-stage human testing aims to restore immune balance (suppressing harmful inflammation) rather than broadly wiping out immune cells, which could mean future treatments that reduce chronic pain, organ damage and lifelong immunosuppression for people with autoimmune disease or transplant patients, and offer safer, more durable control of disease activity compared with current options.

Quell expects initial CHILL readouts in 2027 and is prioritising QEL‑005 while exploring partnerships to progress other assets after platform‑validating data from QEL‑001/LIBERATE.