On October 27th-28th 2025, representatives from Ataxia UK attended the first Clinical Trials in Ataxia (CTAX) conference in Amsterdam. CTAX was organised by Ataxia UK, the National Ataxia Foundation (NAF), the Friedreich’s ataxia research alliance (FARA), and the Ataxia Global Initiative (AGI).
The conference was attended by 120 invited researchers, patient group representatives, pharmaceutical companies, and representatives from the EU and US drug regulators (the EMA and the FDA). The aim of the conference was to identify lessons learned in clinical research, and build a consensus around outcome measures and biomarkers. These are central areas of clinical research that are common to all types of ataxia, and they become increasingly important when potential treatments enter clinical trials and the regulatory process.
Biomarkers in ataxias:
One of the main topics under discussion were biomarkers. Biomarkers are defined as
“a characteristic that is measured as an indicator of normal biological processes, pathogenic processes, or responses to an exposure or intervention, including therapeutic interventions”
This means biomarkers are required to measure progression of ataxia, as well as to measure the effect of a potential treatment being tested in a clinical trial. We heard from researchers studying fluid biomarkers and MRI biomarkers, to be used in trials and monitoring of a range of ataxias. Whilst progress is being made, we need more biomarkers that are sensitive to change, and their clinical relevance needs to be defined.
Natural history studies in ataxias:
We heard from pharma representatives about using data from natural history studies to compare to treatment groups in clinical trials. This highlighted the importance of collecting reliable, thorough, long term natural history data.
Patient-reported outcomes measures:
Day one ended with a session on the clinical meaningfulness of clinical and patient reported outcome measures. These are the measures that are used in clinical trials to determine whether the treatment being tested improves the symptoms or slows the progression of ataxia. Clinical researchers and regulators agree that these outcome measures need to be clinically relevant, which means that a person with ataxia taking a potential medication needs to feel an improvement or stabilization in their health or day-to-day living. Clinical meaningfulness is being looked at for all types of outcome measures, and is an important topic when it comes to gaining regulatory approval for a potential treatment. In this session, we also heard from the EMA and the FDA on their perspective, and the importance of contacting them early in the drug development process.
Learning from other conditions:
The second day of the conference included speakers from other neurological conditions, such as ALS and Huntington’s Disease. As potential ataxia treatments are now reaching late-stage clinical trials, and the drug regulatory processes, we can learn a lot from other conditions that are facing the same problems as the ataxia research field.
In summary:
The success of potential ataxia treatments depends on sensitive biomarkers, high quality natural history data, and clinically meaningful outcome measures. Together, these topics underline the importance of good clinical trial design. We ended the conference by discussing how we can move forward together to address these questions and ensure that the ataxia field is ready for late-stage clinical trials and the drug regulatory process.
The CTAX Steering Committee plan to pull together the main topics from the conference for a consensus paper, and Ataxia UK will continue to represent the interests of people living with and affected by ataxia as we support this work.
