A Study of CST-103 Co-administered With CST-107 in Subjects With Parkinson's Disease Having Freezing of Gait (CLIN-012)

Inclusion Criteria: * Male or female subjects ≥ 30 and ≤ 80 years of age, at time of informed consent. * Diagnosed with Parkinson's Disease, as defined by the United Kingdom Parkinson Disease Brain Bank criteria. * At least 3 months incidence of typical freezing of gait (FOG) symptoms defined as the inability to move the feet despite the intention to walk including at least one of the following FOG patterns: start hesitancy, freezing at making turns or when passing through a doorway, spontaneous freezing during continued walking, or freezing of gait related to a simultaneous mental or physical activity. * Freeze at least once per week (minimum score of 2 on item 3 of the FOG-Q) for at least 2 seconds (minimum score of 1 on item 4 of FOG-Q). * Willing to attend assessment visits in the practically defined Off state having withdrawn from dopaminergic therapy: L-dopa preparations from midnight, Dopamine Agonists/Monoamine Oxidase-B Inhibitor for 36 hours prior to visit. Patients with device assisted therapies (i.e. Deep Brain Stimulation, L-dopa intestinal gel or subcutaneous apomorphine) to withdraw therapy for a minimum 30 minute period (maximum 2 hours) to achieve their clinically agreed Off state. * Unless confirmed to be azoospermic (vasectomized or secondary to medical cause), males must agree to use a male condom from Day 1 throughout the study when having penile-vaginal intercourse with a woman of childbearing potential who is not currently pregnant. Men with a pregnant…