Safety of Urate Elevation in Parkinson's Disease (SURE-PD)

This study has been completed.
Massachusetts General Hospital
Harvard School of Public Health
University of Rochester
Michael J. Fox Foundation for Parkinson's Research
Information provided by (Responsible Party):
Michael Schwarzschild, The Parkinson Study Group Identifier:
First received: January 27, 2009
Last updated: March 20, 2013
Last verified: March 2013

The purpose of this study is to determine the safety and tolerability of inosine and its ability to raise urate levels in blood and cerebral spinal fluid in individuals with early Parkinson disease. This will determine whether it is appropriate to proceed with a larger study of inosine's ability to modify the rate of disability progression in PD.

Condition Intervention Phase
Parkinson Disease
Drug: Placebo
Drug: inosine
Phase 2

Study Type: Interventional
Study Design: Allocation: Randomized
Endpoint Classification: Safety Study
Intervention Model: Parallel Assignment
Masking: Double Blind (Subject, Investigator)
Primary Purpose: Treatment
Official Title: A Randomized, Double-blind, Placebo-controlled, Dose-ranging Trial of Oral Inosine to Assess Safety and Ability to Elevate Urate in Early Parkinson's Disease

Resource links provided by NLM:

Further study details as provided by The Parkinson Study Group:

Primary Outcome Measures:
  • Tolerability as defined as the extent to which an assigned treatment can be continued without dose reduction for more than 4 weeks due to adverse experience(s). [ Time Frame: 12 weeks and 2 years ] [ Designated as safety issue: Yes ]
  • Safety as defined as absence of serious adverse experiences that collectively warrant terminating an inosine treatment dose or the trial, as determined by the Data and Safety Monitoring Committee. [ Time Frame: 12 weeks and 2 years ] [ Designated as safety issue: Yes ]

Secondary Outcome Measures:
  • urate levels in serum/CSF [ Time Frame: 12 weeks and 2 years ] [ Designated as safety issue: No ]
  • oxidative damage biomarker [ Time Frame: 6 months and 2 years ] [ Designated as safety issue: No ]

Enrollment: 75
Study Start Date: June 2009
Study Completion Date: December 2012
Primary Completion Date: December 2012 (Final data collection date for primary outcome measure)
Arms Assigned Interventions
Placebo Comparator: [A:]
Placebo to produce no urate elevation
Drug: Placebo
500 mg of inactive substance per capsule; 1 to 6 capsules per day (in up to 3 divided doses) for 2 years; dosing adjusted algorithmically to parallel that in the inosine arms
Experimental: [B:]
Inosine to produce a mild urate elevation
Drug: inosine
500 mg of active substance per capsule; 1 to 6 capsules per day (in up to 3 divided doses) for 2 years; dosing titrated to a mildly elevated serum urate range of 6.1 - 7.0 mg/dL
Other Name: hypoxanthine 9-β-D-ribofuranoside
Experimental: [C.]
Inosine to produce a moderate urate elevation
Drug: inosine
500 mg of active substance per capsule; 1 to 6 capsules per day (in up to 3 divided doses) for 2 years; dosing titrated to a moderately elevated serum urate range of 7.1 - 8.0 mg/dL
Other Name: hypoxanthine 9-β-D-ribofuranoside

Detailed Description:

Background & Rationale:

Convergent epidemiological and clinical observations have identified urate - a major antioxidant and the end product of purine metabolism in humans - as the first molecular predictor of both the risk and the progression of typical Parkinson's disease (PD). Among some 1600 early PD patients enrolled in the DATATOP and PRECEPT clinical trials, those with baseline serum urate levels in the highest quintile (i.e., in the upper normal range) displayed a 40% slower rate of clinical (disability) progression compared to those with baseline urate at or below the median (with p<0.000001 for trend across quintiles). Similarly, amongst those who underwent serial SPECT brain scans for changes in dopamine transporter (DAT) binding, those with higher baseline serum urate levels displayed a slower rate of radiographic progression (loss of striatal DAT). Moreover, urate levels in baseline CSF samples also correlate inversely with rates of clinical progression. Although this link between urate and a slower decline in PD appears reproducible and robust, the critical question of causality remains to be answered by a well-designed clinical trial. The biological plausibility of neuroprotection by urate strengthens the rationale for expedient pursuit of a trial. The availability of established pharmacological approaches to elevating urate makes such a trial feasible. In particular, inosine, an orally bioavailable, CNS-penetrant purine precursor of urate, offers a practical strategy as it can readily elevate serum urate, has been widely consumed as a nutritional supplement, and has been administered chronically in several multi-year clinical trials for multiple sclerosis. Before embarking on a neuroprotection trial of inosine for PD, careful assessment of the safety, validity and methodology of this approach in PD patients is warranted.

Specific Aims:

The main goal of the study is to determine whether inosine is suitable for phase III evaluation of its ability to modify the rate of disability progression in PD. Specific primary aims entail the determination of the safety and tolerability of oral inosine, and its ability to elevate urate levels in serum or CSF; and the selection of an optimal dosing regimen. Secondary aims entail the further optimization of a possible phase III study design.


A placebo-controlled double-blind dose-ranging randomized trial of inosine will be conducted in early PD. Ninety untreated subjects diagnosed with idiopathic PD and with a serum urate below the population mean (~6 mg/dL) will be enrolled at 17 North American sites and randomized to one of three treatment groups (n=30): 1) placebo, 2) inosine dosed to produce a mild elevation in serum urate, and 3) inosine dosed to produce a moderate elevation. Tolerability, validity (urate elevation), dosage and symptomatic efficacy will be assessed after 12 weeks of treatment. Contingent on adequate tolerability and validity as assessed in this short-term analysis, the study will continue for 2 years total duration with 2 groups (placebo and a merged single inosine dosing group) or the original 3 to assess long-term tolerability and safety, which will focus on main known risks of urolithiasis and gouty arthritis and the theoretical risk of cardiovascular disease.


This study will determine whether a phase III trial of inosine as a potential neuroprotectant in PD is warranted. If it is, then the present study could shorten substantially the lead time, and through optimization of key design features would enhance the likelihood of its safety and success.


Ages Eligible for Study:   30 Years and older
Genders Eligible for Study:   Both
Accepts Healthy Volunteers:   No

Inclusion Criteria:

  • Idiopathic PD with at least two of the cardinal signs of PD (resting tremor, bradykinesia, rigidity)
  • Currently not taking or needing any treatment for PD other than an MAO-B inhibitor
  • Age 30 or older at the time of PD diagnosis
  • Diagnosis of PD made within past 3 years
  • Specified serum urate levels at screening visits

Exclusion Criteria:

  • History of kidney stones, gout, stroke, or heart attack
  • History of renal disease or certain cardiovascular problems within the past year
  • Acidic urine (pH ≤ 5.0), uric acid, or urate crystalluria at screening
  • Use of certain medications including co-enzyme Q, creatine, more than 50 IU of vitamin E daily, and more than 300 mg of vitamin C daily. (A standard daily multivitamin is permitted.)
  • Use of anti-PD and other medications targeting central nervous system dopamine transmission
  • Known unstable medical or psychiatric condition that may compromise participation in the study
  • Women who are pregnant or lactating
  Contacts and Locations
Please refer to this study by its identifier: NCT00833690

United States, California
University of Southern California
Los Angeles, California, United States, 90083
United States, Connecticut
Eastern Connecticut Neurology Specialists, LLC
Manchester, Connecticut, United States, 06040
Institute for Neurodegenerative Disorders
New Haven, Connecticut, United States, 06510
United States, Florida
Parkinson's Disease and Movement Disorders Center of Boca Raton
Boca Raton, Florida, United States, 33486
United States, Illinois
Rush University Medical Center
Chicago, Illinois, United States, 60612
United States, Louisiana
Ochsner Clinic Foundation
New Orleans, Louisiana, United States, 70121
United States, Massachusetts
Massachusetts General Hospital
Boston, Massachusetts, United States, 02114
Boston University Medical Center
Boston, Massachusetts, United States, 02118
United States, Michigan
Michigan State University
East Lansing, Michigan, United States, 48824
United States, Minnesota
Struthers Parkinson's Center
Golden Valley, Minnesota, United States, 55427
United States, North Carolina
Duke University School of Medicine
Durham, North Carolina, United States, 27705
United States, Ohio
University of Cincinnati
Cincinnati, Ohio, United States, 45219
Cleveland Clinic
Cleveland, Ohio, United States, 44195
United States, Oregon
Oregon Health and Science University
Portland, Oregon, United States, 97239
United States, Rhode Island
Butler Hospital Movement Disorder Program
Providence, Rhode Island, United States, 02906
United States, Texas
Scott & White Hospital
Temple, Texas, United States, 76508
Sponsors and Collaborators
The Parkinson Study Group
Massachusetts General Hospital
Harvard School of Public Health
University of Rochester
Michael J. Fox Foundation for Parkinson's Research
Principal Investigator: Michael A Schwarzschild, MD, PhD Massachusetts General Hospital
  More Information

Additional Information:
No publications provided

Responsible Party: Michael Schwarzschild, Principal Investigator, The Parkinson Study Group Identifier: NCT00833690     History of Changes
Other Study ID Numbers: INO-PD-P2-2008
Study First Received: January 27, 2009
Last Updated: March 20, 2013
Health Authority: United States: Food and Drug Administration

Keywords provided by The Parkinson Study Group:
Parkinson's disease
Parkinson disease
uric acid
cerebrospinal fluid

Additional relevant MeSH terms:
Parkinson Disease
Parkinsonian Disorders
Basal Ganglia Diseases
Brain Diseases
Central Nervous System Diseases
Nervous System Diseases
Movement Disorders
Neurodegenerative Diseases processed this record on April 14, 2014