18-months Safety Follow-up Study of AADvac1, an Active Tau Vaccine for Alzheimer's Disease

1. Completion of visit V8 of the AADvac1 phase I study AXON CO 18700 (EUDRACT 2012-003916-29).

2. Informed consent capability (as determined by an independent neurologist/psychiatrist).

3. Written informed consent signed and dated by the patient and the caregiver.

4. Availability of a partner/caregiver knowing the patient and being able to accompany the patient to the visits

5. Adequate visual and auditory abilities and language skills to allow neuropsychological testing.

6. Female patients are only eligible for the study if they are either surgically sterile or at least 2 years postmenopausal.

7. Sexually active males must be using reliable contraception methods (i.e. condoms) or be surgically sterile

1. Pregnant women.

2. Participation in another clinical trial during the course of this study.

3. Contraindication for MRI imaging such as MRI-incompatible metallic endoprosthesis or MRI-incompatible stent implantation

4. History and/or presence of autoimmune disease, if considered relevant by the investigator.

5. Significant systemic illness (e.g., chronic renal failure, chronic liver disease, poorly controlled diabetes, poorly controlled congestive heart failure, congenital long QT syndrome, other deficiencies), if considered relevant by the investigator.

6. Current treatment with immunosuppressive drugs.