D-SPARK: A Clinical Trial of D-Serine for Modifying Parkinson's Disease Progression

Summary

This clinical study, designed as a randomized, double-blind, placebo-controlled trial, aims to investigate if modulation of the N-methyl-D-aspartate receptor (NMDAR) via its co-agonist D-serine has therapeutic benefits in Parkinson's disease (PD). All patients will receive both placebo and D-serine over different time periods during the study.

Preclinical studies have shown that blocking glycine transporters, which elevates endogenous glycine levels, can restore NMDAR function and improve motor deficits in PD models. A clinical trial demonstrated that oral D-serine (30 mg/kg/day for 6 weeks) significantly reduced extrapyramidal and abnormal involuntary movements in PD patients compared to placebo, with improvements observed in both motor and non-motor symptoms. D-serine supplementation has shown an acceptable safety profile with doses up to 120 mg/kg showing no significant adverse effects in clinical studies.

The D-SPARK trial primarily aims to determine the efficacy of D-serine supplementation on clinical severity of PD as measured by the Movement Disorder Society Unified Parkinson's Disease Rating Scale (MDS-UPDRS).

Secondary aims are to determine the efficacy of D-serine supplementation on improving dopaminergic nigrostriatal innervation as measured by single-photon emission tomography (SPECT) based imaging of the dopamine transporter (DaT-scan) and cognition as measured by the California Verbal Learning Test version 2 (CLVT-II).

The study will include 100 persons with Parkinson's disease (PwPD) diagnosed no longer than 5 years before baseline. Participants will be randomly assigned to receive D-Serine 4000 mg daily or placebo for defined periods of time during a 58 week treatment period, followed by a 12 week washout period.

Participants will undergo:

* Clinical evaluations, including clinical rating scales and questionnaires.
* Cognitive assessments.
* Bio sampling of whole blood and blood plasma.
* Single-photon emission tomography (SPECT) imaging of dopamine transporter levels (DaT-scan)

The outcomes of this study could potentially demonstrate that D-serine reduces symptom severity in Parkinson's disease and/or has an impact on the clinical trajectory of Parkinson's disease, benefiting persons living with Parkinson's disease, their families and society as a whole.

Conditions

Parkinson s Disease
Parkinson Disease (PD)

Interventions

DIETARY_SUPPLEMENT

D-serine

D-serine 2 x 500 mg and 2 x Placebo oral capsules administered twice daily the first week of intervention, then uptitrated to D-serine 4 x 500 mg twice daily for the remainder of the intervention.

DIETARY_SUPPLEMENT

Placebo

Placebo 2 x oral capsules administered twice daily.

Sponsors & Collaborators

SPARK NS
collaborator UNKNOWN
University of Bergen
collaborator OTHER
Haukeland University Hospital
lead OTHER

Study Design

Allocation: RANDOMIZED
Purpose: TREATMENT
Masking: TRIPLE
Model: CROSSOVER

Eligibility

Min Age: 40 Years
Max Age: 80 Years
Sex: ALL
Healthy Volunteers: No

Timeline & Regulatory

Start: 2026-01-20
Primary Completion: 2028-03-31
Completion: 2028-12-31

Countries

Norway