The purpose of this study is to document the long-term safety and tolerability after intracerebroventricular (ICV) administration of sNN0031 (PDGF-BB) in patients who participated in study sNN0031-001

Inclusion Criteria:

• Previous participation in study sNN0031-001 with completion of 12 study weeks without development of clinically significant safety concerns, defined as being any drug-related or device related serious adverse event that resulted in premature termination of treatment or a medical device incident that could not be resolved during the conduct of study sNN0031-001
• The patient has a diagnosis of idiopathic PD
• The patient has been given written and verbal information about the follow-up study, has had the opportunity to ask questions about the study, and understands the time and procedural commitments
• The patient has provided written informed consent to participate in the follow-up study

Exclusion Criteria:

• The patient has been included or participates in another clinical study after participation in Study sNN0031-001
• The patient has, since participation in study sNN0031-001, had functional neurosurgical treatment for PD (e.g., deep brain stimulation).
• Patients will only be excluded from participation in the event of a laboratory test abnormality that is indicative of a medical condition requiring treatment which, in the opinion of the investigator, is not compatible with participation in the present study

Patients diagnosed with idiopathic PD of moderate severity who have completed participation in study sNN0031-001.