• using a global statistical test this study will compare disease progression at 5 years between the creatine and placebo groups. [ Time Frame: MINIMUM OF 5 YEARS TO A MAXIMUM OF 7 YEARS ] [ Designated as safety issue: Yes ]
  

• comparison of creatine and placebo groups on efficacy, safety and tolerability between baseline and 5 years of follow-up. [ Time Frame: MINIMUM OF 5 YEARS TO A MAXIMUM OF 7 YEARS ] [ Designated as safety issue: Yes ]
  

Parkinson's disease (PD) affects nearly a million Americans, a number that will increase over the coming decades as the population ages. Symptoms of PD may include tremor, rigidity or stiffness of the limbs and trunk, slowness of movement, and impaired balance and coordination. These problems occur because as PD worsens, some of the brain cells that control body movement die.

This study will determine if creatine——an investigational compound——is able to slow the progression of PD. Creatine, a widely used dietary supplement is thought to improve exercise performance. In animal models and human studies, creatine has been shown to be well tolerated and may have some ability to protect brain cells.

In the NET-PD LS-1 study, 1,720 participants will be randomly assigned to receive either creatine or a placebo (inactive substance). Participation in this study lasts a minimum of 5 years and includes at least 9 follow-up clinic visits and at least 3 telephone calls.

Inclusion Criteria:

• Willing and able to give informed consent and willing to commit to long-term follow-up
• PD (asymmetric features including slowness (bradykinesia) plus resting tremor and/or rigidity) within 5 years of diagnosis
• Treated/responsive to dopaminergic therapy (dopamine agonists or levodopa) for at least 90 days, but not more than 2 years.

Exclusion Criteria:

• Use of creatine 14 days prior to baseline or during the study
• History of known hypersensitivity or intolerability to creatine
• Any unstable or clinically significant condition that would impair the subject's ability to comply with long term study follow-up
• Other know or suspected causes of parkinsonism (e.g. metabolic, drug induced, etc.), or any significant features suggestive of a diagnosis of atypical parkinsonism.