(HealthDay News)  — Oral inosine treatment does not impact clinical progression for people with early Parkinson disease (PD), according to a study published in the Sept. 14 issue of the Journal of the American Medical Association.

Michael A. Schwarzschild, M.D., Ph.D., from the Mass General Institute for Neurodegenerative Disease in Boston, and colleagues conducted a phase 3 trial of oral inosine treatment in early PD. Overall, 298 patients with PD not yet requiring dopaminergic medication, with striatal dopamine transporter deficiency, and with serum urate below the population median concentration were randomly assigned to either inosine, dosed to increase serum urate concentrations to 7.1 to 8.0 mg/dL, or matching placebo (149 each) for up to two years.

The study closed early, with 273 participants completing the trial, based on a prespecified interim futility analysis. The researchers observed no significant difference in clinical progression rates for participants randomly assigned to inosine or placebo (rate of change in the Movement Disorder Society Unified Parkinson Disease Rating Scale score, 11.1 versus 9.9 points per year). A sustained elevation of serum urate was seen in the inosine group, while there was little change in the placebo group (2.03 versus 0.01 mg/dL). No significant differences were seen between the groups for secondary efficacy outcomes, including dopamine transporter binding loss.

“While our study did not rule out a protective effect of urate in Parkinson’s, it clearly showed that increasing urate did not slow disease progression based on clinical assessments and serial [brain] scan biomarkers of neurodegeneration,” Schwarzschild said in a statement.

Several authors disclosed financial ties to the biopharmaceutical, publishing, and medical technology industries; the study was partially funded by GE Healthcare.

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