The TIARA trial: Investigating a new treatment for a life-threatening blood disorder
A collaboration with the Aplastic Anaemia Trust to jointly fund a trial testing a cell therapy as a potential new treatment for aplastic anaemia.

Overview
The TIARA trial is investigating the use of regulatory T cells (Tregs) to treat the life-threatening blood disorder aplastic anaemia. This Phase 1 study, led by King’s College Hospital and King’s College London, focuses on addressing the immune dysfunction underlying the condition.
Early results are promising, with participants showing reduced dependence on transfusions, offering hope for those with limited treatment options.
About the TIARA trial
The trial uses expanded autologous Tregs, immune cells collected from the patient, grown in a lab, and reinfused to regulate the immune response and support bone marrow recovery. Patients receive 2 infusions of their expanded Tregs 2 weeks apart and are monitored over 2 years to assess safety and efficacy.
Key early findings include:
- Tregs can be safely expanded and reinfused.
- some participants have achieved significant improvements, including sustained independence from blood transfusions.
- the therapy could provide a less invasive alternative to stem cell transplants.
The trial builds on extensive research at King’s College London, which identified abnormalities in Tregs in patients with aplastic anaemia, paving the way for this innovative therapy.
About aplastic anaemia
Aplastic anaemia is a rare condition where the bone marrow fails to produce enough blood cells, leading to severe fatigue, frequent infections, and life-threatening bleeding. It can affect anyone but is most common in teenagers and people over 60.
Current treatments, such as immune-suppressive therapy and stem cell transplants, often fail to provide lasting solutions, leaving many patients with limited options and poor outcomes.
Impact of the TIARA trial
If successful, the trial has the potential to:
- introduce a personalised therapy using a patient’s own cells, eliminating the need for donor matches and reducing risks like graft-versus-host disease
- restore healthy blood cell production, reducing or eliminating dependence on transfusions
- improve quality of life by addressing the underlying cause of the condition
- pave the way for further advancements in cell-based therapies for rare and autoimmune diseases