The National Institute of Neurological Disorders and Stroke, part of the National Institutes of Health, is looking for individuals to participate in clinical studies. Participating in clinical trials allows you to play an active role in research on the nature and causes of many disorders of the brain and nervous system, and to possibly help physician-scientists develop future treatments. The information below is designed to help you quickly learn about actively recruiting research studies for which you or someone you know may be eligible.


NINDS Announces Early Study Closure of SURE-PD3 Trial

The National Institute of Neurological Disorders and Stroke (NINDS) has accepted the Data and Safety Monitoring Board’s (DSMB) recommendation to stop SURE-PD3, the Study of URate Elevation in Parkinson’s disease (PD), after an interim analysis showed it would be unlikely to demonstrate benefit of long-term treatment with inosine in people with PD. The trial was testing whether a treatment that raises blood levels of the natural antioxidant urate for two years slows the rate of worsening in PD. The randomized, placebo-controlled, double-blinded trial, funded by the NINDS, was conducted nationwide at 57 clinical sites of the Parkinson Study Group (PSG). It was led by investigators at Massachusetts General Hospital (MGH) and the University of Rochester, with support from the Michael J. Fox Foundation.  

After two thirds of the patient data were collected, the study’s independent DSMB reviewed an unblinded analysis of the primary outcome, measurement of disease progression. Study statisticians determined that even if the trial were continued so that all participants were treated for the full two years, it would unlikely show benefit of inosine by the primary measurement.  Accordingly, the DSMB recommended that the study be ended early. The DSMB did not note any significant safety concerns though high levels of urate are known to cause gout. 

Site investigators and coordinators have informed SURE-PD3 participants of the study closure. Patients will be invited to continue as volunteers in the NINDS-funded AT-HOME-PD study which focuses on how telehealth assessments via video, smartphone tracking, and computer-based questionnaires can improve the way PD trials are performed.

The SURE-PD3 trial will be closed out over the next six months, and final results are expected by the end of 2019.  The NINDS is very appreciative of the efforts of patients, care givers and investigators in this important clinical trial.  

Eligibility Criteria:


  • Fulfillment of diagnostic criteria for idiopathic (typical) PD with at least two of the cardinal signs of PD (e.g., tremor at rest, slowness) as assessed by the doctor/site investigator.
  • Absence of current or imminent (within 90 days of enrollment) PD disability requiring dopaminergic medication, as assessed by the site investigator.
  • Diagnosis of PD made no more than 3 years prior to first screening visit.
  • Non-fasting serum urate ≤ 5.7 mg/dL at first screening visit.


  • Normal results of a dopamine transporter (DAT) brain scan (i.e., without evidence of dopamine deficit).
  • History of gout, kidney stones containing uric acid or urate, recurrent stones of unknown type, heart attack, or stroke.
  • Low urine pH (≤ 5.0) or low kidney function (estimated glomerular filtration rate < 60 ml/min/1.73 m2).
  • Congestive heart failure with a documented ejection fraction below 45%, or a history of severe chronic obstructive pulmonary disease.
  • Signs of dementia or significant cognitive impairment (assessed as Mini Mental State Exam score < 25).
  • Use of any anti-parkinsonian medication within 60 days of baseline, or in excess of 90 days, except that a stable dose of a monoamine oxidase-B (MAO-B) inhibitors like rasagiline or selegiline is allowed.
  • Use of the following within 30 days prior to the baseline visit: inosine, more than 50 IU of vitamin E daily, or more than 300 mg of vitamin C daily, methylphenidate, amphetamines, monoamine oxidase-A inhibitors, neuroleptics or other dopamine blocking drugs.
  • Use of the following within 90 days prior to the DAT neuroimaging screening evaluation: modafinil, armodafinil, metoclopramide, alpha-methyldopa, methylphenidate, or amphetamine derivative.
  • Known unstable medical or psychiatric condition that may compromise participation in the study.
  • Participation in another investigational treatment study within 30 days prior to the baseline visit.

Study Design:

Allocation: Randomized, Endpoint Classification: Efficacy Study, Intervention Model: Parallel Assignment, Masking: Double Blind (Subject, Caregiver, Investigator, Outcomes Assessor)

Study Location:

Multiple U.S. Locations