Phase IB Follow-up Study to Assess Boost Immunization with AFFITOPE® PD01A

Study Rationale:
PD01A is an alpha-synuclein-targeting vaccine. Accumulation and/or aggregation of alpha-synuclein is central to the pathogenesis of Parkinson’s disease, and its reduction is expected to positively modify the course of the disease. PD01A has been tested in a first-in-humans Phase IA study. Results obtained demonstrated multiple (n=4) subcutaneous vaccinations with two different doses of PD01A (15 and 75 µg) to be safe and well tolerated. Evaluation of patients’ blood demonstrated the induction of the intended alpha-synuclein-reactive antibodies.

Hypothesis:
Our hypothesis is that it is possible to boost the antibody response generated by the initial monthly PD01A administrations.

Study Design:
Patients who have already received four immunizations with PD01A within the prior study will be offered a fifth immunization. To this end, they will be randomized, depending on their initial dose, to receive the low (15 µg) or the high (75 µg) dose of PD01A. Before applying the boost, baseline evaluations for various parameters (e.g., immune response, motor- and non-motor scales) will be conducted. After the boost, patients will be followed for six months and regularly assessed for adverse events, for immune response and for clinical activity of the boost injection of PD01A.

Impact on Diagnosis/Treatment of Parkinson’s Disease:
A vaccine that would be capable of slowing or halting the process underlying Parkinson’s disease would fundamentally impact the way we treat the disease. It would represent the first causal treatment.

Next Steps for Development:
This project is the next step towards Phase II testing of PD01A. Defining the conditions for keeping antibodies elevated over time is an essential next step for the clinical development of PD01A.

Trial phase: IB