Dominantly Inherited Alzheimer Network Trial: An Opportunity to Prevent Dementia. A Study of Potential Disease Modifying Treatments in Individuals With a Type of Early Onset Alzheimer's Disease Caused by a Genetic Mutation (DIAN-TU)

This study is looking for people between 18 and 80 years old. A very important part of joining is that you must know you have the specific faulty gene that causes this early-onset, inherited type of Alzheimer's disease. You should also be within 10 years before or 10 years after the age when symptoms are expected to start, or have already started. You can be eligible if your memory and thinking are normal, or if you have very mild problems with memory or thinking (what doctors call mild cognitive impairment or mild dementia).

To take part, you'll need to be able to speak the study's approved language well and have a good level of understanding previously. You also need to be able to have brain scans (MRI, PET) and a lumbar puncture (a small test involving fluid from your spine). It's also important to have a 'study partner' – someone who knows you well and can give accurate information about your memory and daily activities.

There are also some reasons why you might not be able to join. For example, if you have other serious brain conditions, a high risk of suicide, or certain metal implants in your body that would make MRI scans unsafe. The study team will check all these details carefully with you.

If you join the study, you will receive either one of the new study medicines (E2814 or Lecanemab) or a 'matching placebo'. A placebo looks exactly like the study medicine but contains no active drug, and is used so researchers can fairly compare how the real medicine works. You won't know whether you're getting the active medicine or the placebo, and neither will your study doctor.

Your participation will involve regular visits to the study clinic, likely over several years. At these visits, you'll have various tests, including memory and thinking assessments, blood tests, and special brain scans (MRI and PET scans) to look at changes in your brain. You will also need to have lumbar punctures regularly, where a small amount of fluid is taken from your spine. Your study partner will also be asked to provide information about you at these visits. The exact duration and frequency of visits will be explained by the study team, but it's a long-term commitment.