In Parkinson's Disease, the mitochondrial membranes in cells that produce dopamine become damaged by oxidants, leading to the death of these cells and progressive tremor, slowness of movement and the loss of neurons in the substantia nigra (a part of the brain that is involved in movement). Mitoquinone is targeted to reach the membrane of mitochondria and provide protection from damaging oxidants. There are no treatments currently available to slow the progression of PD and this trial will help advance the development of this unique disease modifying drug.

This trial will enroll 120 participants with untreated early onset of PD. Participants will be randomized to receive 1 of 3 treatments: 40 mg of MitoQ tablets, 80 mg of MitoQ tablets or placebo. The researchers, participants and sponsor will all be blinded to the treatment allocation. Participants will be assessed after 1, 2, 3, 6, 9, 12 months of treatment and again 28 days after their last dose. The effectiveness of the trial drug will be measured via the Unified Parkinson's Disease Rating Scale (UPDRS). The safety of the trial drug will be monitored via regular participant examinations, blood tests, ECG and collecting information on adverse events.

Inclusion Criteria:

1. Informed consent
2. 30 yrs or older
3. Diagnosis of PD (2 or more of bradykinesia; rest tremor, rigidity)
4. Adequate contraceptive measures (females)

Exclusion Criteria:

1. Malignancy within last 2 years
2. Pregnancy & breast-feeding
3. Treatment with any anti-PD drugs within 30 days of enrolment
4. Prior treatment with anti-PD medication exceeding 42 days in total
5. Medication-induced PD/PD not of idiopathic origin
6. CoQ10/idebenone doses of 300mg/day or higher within 120 days, >25mg/day within 7 days of enrolment
7. Methylphenidate HCl, neuroleptics, reserpine, amphetamines, selegeline or MAOIs within 6 months of enrolment
8. CNS medications at unstable doses within 60 days of enrolment
9. Dietary supplements > 5 x RDI
10. Hypersensitivity to CoQ10, idebenone or any components of the study drug
11. Unable to swallow
12. Diseases with features of PD
13. Seizure(s) within 12 months prior to enrolment
14. UPDRS tremor score of 4
15. Hamilton Depression Rating Scale score > 10
16. History of stroke
17. Requirement for dopaminergic drugs
18. Modified Hoehn & Yahr score > 2.5
19. History of brain surgery for Parkinson's disease
20. History of structural brain disease / congenital brain abnormality
21. History of ECT
22. Any other clinically significant medical or psychiatric condition or lab abnormality
23. Enrolment in any other pharmacological study within 30 days of enrolment