This is a randomized, placebo-controlled, parallel group, patient-blind, single-center phase I clinical trial of repeated once every 4 weeks administration by subcutaneous injection of AFFITOPE® PD01A, adsorbed to aluminium oxide in 30 patients with PD-GBA over a treatment period of 8 weeks. Patients will be randomized in a 2:1 ratio to two different treatment groups: A) 75 µg AFFITOPE® PD01A, adsorbed to aluminium oxide and B) placebo (= 1 mg aluminium oxide).