The trial is designed as a patient-blinded, single-center, randomized, controlled, parallel group, phase I clinical study of repeated once every 4 weeks administration by subcutaneous injection of Affitope AD01 alone or adsorbed to aluminum hydroxide in 24 patients with mild to moderate Alzheimer's Disease. In total, each patient will receive 4 immunizations. Patients will be randomized to receive Affitope AD01 alone or adsorbed to aluminum hydroxide. Each treatment group consists of 12 patients. For safety reasons, inclusion of patients will be done in a stepwise manner.