DOSET: New Adaptive Trial Design Improves Dose Optimization for CAR-T Cell Therapy in Early-Phase Cancer Studies
Key Insights
Researchers from ICR, King's College London, and King's College Hospital developed DOSET, a novel statistical framework for early-phase CAR-T therapy trials that simultaneously evaluates safety and efficacy.
DOSET demonstrated superior performance in correctly identifying safe and effective doses compared to existing methods, particularly in small-sample settings common in CAR-T studies.
The design allows trials to stop early when treatments appear ineffective or unsafe, reducing patient exposure to suboptimal doses.
A new statistical methodology called DOSET could transform how early-phase clinical trials identify optimal doses for advanced therapies such as CAR-T cell therapy (search), addressing long-standing challenges in studies where only small numbers of patients can be recruited.
Developed through a collaboration between King's College Hospital, King's College London, and The Institute of Cancer Research (ICR), London, DOSET (Dose Optimization with Simultaneous Efficacy and Toxicity) offers a more efficient and flexible framework for early-phase trial design. The findings were published in the journal ESMO Open and represent the first publication of a novel statistical trial design developed by the ICR Clinical Trials and Statistics Unit (ICR-CTSU) Early Phase and Adaptive Trials Group for one of its clinical trials. The work was supported by grants from Cancer Research UK.
Rethinking Early-Phase Trial Assumptions
Traditional early-phase clinical trials have focused on identifying the maximum tolerated dose, operating under the assumption that higher doses yield greater effectiveness. However, this assumption does not always hold true for newer therapies such as CAR-T cell therapy (search), where dose-response relationships can be considerably more complex.
CAR-T therapy is a highly personalised form of immunotherapy used to treat blood cancers, including leukaemia (search) and lymphoma (search), that have not responded to other treatments or have relapsed. In CAR-T trials, additional challenges arise because studies typically enrol relatively small numbers of patients due to limited eligible populations, the complexity of the treatment, and the need for personalised manufacturing. These constraints make it especially important to extract maximum value from data as they accumulate during the trial.
How DOSET Works
DOSET was developed specifically for a first-in-human CAR-T therapy trial of a next-generation CAR-T cell product (pCAR19 (search)) at King's College Hospital. The design combines several advanced statistical methods into a single adaptive framework, enabling researchers to assess both toxicity and preliminary efficacy simultaneously, rather than focusing on safety alone.
This integrated approach allows the identification of doses that strike a better balance between safety and effectiveness while reducing the number of patients exposed to doses that are either too low to work or too toxic. Additionally, DOSET permits trials to stop early if a treatment appears unlikely to be effective or seems unsafe, thereby protecting patients and improving overall trial efficiency.
Superior Performance in Small-Sample Settings
To evaluate the method, researchers compared DOSET with an existing dose-optimisation approach used in early-phase CAR-T trials. Across a range of realistic clinical scenarios, DOSET demonstrated consistently stronger performance. It showed a higher likelihood of correctly identifying doses that were both safe and effective while maintaining similar levels of patient safety. The design was also better at advising researchers when to stop trials early when no suitable dose could be identified, reducing unnecessary exposure to ineffective treatments.
Importantly, these advantages were observed even in small-sample settings, which are common in CAR-T studies.
Expert Perspectives
Dr Xinjie Hu, first author and former senior trial statistician in the Early Phase and Adaptive Trials Group at ICR-CTSU, said: "Many modern therapies, such as immunotherapies and targeted therapies, do not follow traditional assumptions about how dose relates to effectiveness. In these settings, more flexible trial designs like DOSET could help improve how doses are selected, ultimately supporting better decision-making in early-stage drug development."
Professor Christina Yap, Professor of Clinical Trials Biostatistics and Group Leader of the ICR-CTSU Early Phase and Adaptive Trials Group, noted: "Developing DOSET in close collaboration with clinical teams at King's College Hospital and King's College London allowed us to address a real challenge in early-phase trials – how to make the best possible decisions with limited patient data. It's particularly rewarding to see a methodological innovation progress from concept through to implementation in a real clinical trial and publication."
Dr Reuben Benjamin, Haematologist and Clinical Senior Lecturer at King's College London and Chief Investigator, added: "For advanced therapies such as CAR-T, finding the right dose is not always as straightforward as administering higher doses and expecting a better outcome. Our aim is to identify the precise doses needed to maximise benefit for patients while minimising unnecessary risks. DOSET gives us a more sophisticated way to analyse clinical trial data, and we hope this approach will not only benefit this CAR-T trial but also help improve the development of future cell and gene therapies for patients with blood cancer."
Future Implications
The research team hopes this work will contribute to a broader shift towards evidence-based dose optimisation in early-phase clinical trials, extending beyond CAR-T therapy, and increasing the likelihood that new treatments are identified more quickly. The methodology's publication marks an important milestone in translating statistical innovation into real-world clinical research practice.