Background

HD usually progresses slowly, and symptoms vary from person to person. At the present we cannot tell which symptoms a person with the HD gene will get, or when. The clinical assessments used currently to measure disease progression are not accurate enough. This is an important issue for the evaluation of possible treatments for HD. For instance, therapies that slow down disease progression would need clinical trials involving hundreds of patients over many years. This scenario becomes more complex when we consider HD gene carriers who have no symptoms at all. Dozens of treatments may need to be tested in the next few years. We therefore need ways to reduce the number of participants and duration of clinical trials. We hope that biomarkers will help us identify the most promising drugs.

Description

The Biomarkers Working Group aims to find biomarkers for HD and develop a biomarker-based clinical trial infrastructure. In particular, the aims of the working group are:

1. To identify and validate biomarkers that can be used to track disease progression, detect disease-related changes and monitor treatments that may delay onset of HD.
2. To encourage collaborative HD biomarker research by facilitating sharing of ideas, samples, techniques and results.
3. To establish and conduct major HD biomarker research projects that will delineate the infrastructure and assessment protocols for future clinical trials.
4. To share best practice in biomarkers and HD assessment tools with other complementary groups and organisations, both within EHDN and beyond.

Our working group enjoys fruitful collaborative links with other EHDN Working Groups, especially the Motor Phenotype WG (quantitative motor markers), the Cognitive Phenotype WG (accurate cognitive assessment tools), the Genetic Modifiers WG (investigation of known genetic modifiers as potential biomarkers and known biomarkers as potential genetic modifiers) and the Imaging WG (developing and cross-validating imaging measures as biomarkers). We have numerous worldwide collaborations, especially within the scope of the Predict-HD Study and other Huntington Study Group projects, the HD-Toolkit Project (working towards evidence-based review of HD outcome measures) and the Huntington’s Disease Neuroimaging Initiative (HDNI).

Current projects

The Biomarkers Working Group focuses on the following projects:

1. Collection and biobanking of biomarker samples that can be used for multiple biomarker projects.
2. Cross-sectional and longitudinal biomarker discovery projects.
3. Cross-sectional and longitudinal biomarker validation projects.
4. TRACK-HD: the Biomarkers Working Group’s flagship multi-centre biomarker evaluation project.
5. TRACK-HD is a major international study that aims to determine what combination of measures is the most sensitive for detecting change over the natural course of pre-manifest and early HD, and validate these as potential outcome measures for use in future therapeutic trials.
6. EHDN REGISTRY: We helped to design and test the biomarker component of the REGISTRY Project and are closely involved in the analysis of the results.

The members of our working group are involved in many projects, including:

1. Investigation of inflammatory changes in HD (led by Sarah Tabrizi, London)
2. Investigation of cholesterol metabolites as biomarkers (Stefano Di Donato, Milano)
3. Brain-derived neurotrophic factor (BDNF) as a potential biomarker (Elena Cattaneo, Milano)
4. Gene expression markers (Hoa Nguyen, Tübingen, and Borut Peterlin, Ljubljana)
5. Objective clinical markers (Roger Barker, Cambridge)
6. Metabolic markers (Roger Barker, Cambridge, and Alexandra Dürr, Paris)
7. Huntingtin aggregates as possible biomarkers (Gill Bates, London, and Novartis PLC)

Study participation

Participation in biomarkers projects is a very useful way to help us all move closer to treatments that will slow down the progression of HD. You can be as involved as you like: Some studies require only a urine sample, while others involve regular or more detailed assessments, with longer sessions and collection of more samples (such as blood).
Patients enrolled at any EHDN-associated centre are likely to be able to enrol in at least one project (REGISTRY), which includes a biomarker research component. Some individual centres have specific biomarker projects active in addition, and will inform potential subjects directly. Most participants are recruited through HD clinics. Some centres have their own sources of information, such as websites or HDA bulletin boards, which patients can use to volunteer for studies.
Most biomarker studies involve the donation of at least one sample of urine, blood or other tissue, such as spinal fluid or muscle. In addition, most studies will require basic clinical information, such as the result of an HD genetic test, what symptoms you have and how long you have had them, and what medicines you are taking. Some studies are much more detailed and collect information like family history and questions about your mood. The frequency of the visits varies greatly. Some studies are one-offs, so your involvement is over when you have donated a sample of urine or blood. Others (like TRACK-HD) involve regular follow-up visits, usually once a year.
All research of Biomarkers Working Group members carries the ethical approval of local and national research ethics committees. This includes requirements for proper data protection, such as the use of pseudonyms.

Membership

The Biomarkers Working Group has 122 regular members and 55 honorary members (June 2008). Membership is open to all researchers involved in HD biomarker research, including researchers actively involved in collecting biosamples for the REGISTRY Study, as well as those with individual or collaborative biomarker projects. In addition, membership applications are encouraged from researchers with interests related to biomarker identification and validation, such as bioinformaticians or researchers with perspectives on biomarker research from other disease areas and from the industry. From time to time, we offer regular or honorary membership to researchers from other disciplines (such as neuroimaging, statistics and motor assessment). Working Group members are encouraged to present and discuss their projects and findings at our regular face-to-face meetings. These are held every 6 to 12 months.

, Germany