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Parkinson s DiseasePhase 2D-SPARKNCT07312110

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

A Phase 2 study testing D-serine in people with Parkinson s Disease and Parkinson Disease (PD), run by Haukeland University Hospital at 11 sites in Norway.

Recruiting

Looking for participants now. Contact the study team or a site below to ask about taking part.

Sites and contacts
Official record
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Trial 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). Read more about this study

Who is it for?
Ages 40 to 80 years
Conditions the study is for
Parkinson s Disease, Parkinson Disease (PD)
What is being tested?
D-serine
Type of treatment
Pill or oral medicine
Could I receive a placebo?
Yes, some participants may receive a placebo
How many people
100 participants
Where
11 sitesNorway
Study dates
20 Jan 2026to Dec 2028
Phase
Phase 2
Are there results?
Not yet: the study is under way

Key requirements

Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.

  • Ages 40 to 80 years
  • All sexes
  • No healthy volunteers
  • Adult, Older adult

Who may be able to join

  • A clinical diagnosis of PD* according to the clinically established MDS clinical diagnostic criteria for Parkinson's disease within 5 years.
  • [¹²³I]FP-CIT single photon emission CT (DaTscan) confirming dopaminergic nigrostriatal denervation.
  • Hoehn and Yahr score < 3 at enrollment.
  • Optimal symptomatic PD treatment, not requiring adjustments, for at least 2 weeks.
  • Age ≥40 and ≤ 80 years at time of enrollment.

Who cannot join

  • Dementia or neurodegenerative disorder other than PD at baseline visit.
  • Atypical parkinsonism (PSP, MSA, CBD vascular parkinsonism, or drug induced parkinsonism).
  • Any known monogenic cause of PD (GBA1 variation is accepted).
  • Any psychiatric disorder that would interfere with compliance in the study.
  • Any severe somatic illness that would make the individual unable to comply and participate in the study.
  • Use of D-serine supplementation within 90 days of enrolment.
Show all 13Show fewer
  • Metabolic, neoplastic, or other physically or mentally debilitating disorder at baseline visit.
  • Active of planned pregnancy during trial period.
  • Cognitive impairment as measured by the Mini Mental Status Exam MMSE) < 20.
  • Weight < 45 kg.
  • Urinary albumin/creatinine ratio ≥ 20 mg/mmol at time of enrollment.
  • Participants will be excluded if they have CKD stage 3 or higher, defined as:
  • Estimated golumerular filtration rate (eGFR) < 60 mL/min/1.73min^2 at screening, calculated using the CKD-EPI 2021 creatinine equation.

Trial locations and contacts

11 sites in 1 country. Contact the study team or a site near you to ask about taking part.

11 sites in 1 country

Norway11 sites, 11 recruiting
  • Nevro Arendal Soerlandsklinikken

    Arendal, Agder, 4838

    Karen Herlofson, MD, PhD, Karen.Herlofson@nevroarendal.no

    Karen Herlofson, MD, PhD

    Recruiting
  • Haukeland University Hospital

    Bergen, Vestland, 5021

    Charalampos Tzoulis, MD, PhD, 55975061 ext. +47, charalampos.tzoulis@helse-bergen.no

    Haakon Berven, MD, 55755045 ext. +47, haakon.berven@helse-bergen.no

    Recruiting
  • Bodø Hospital (Nordland Hospital)

    Bodø, Nordland, 8006

    Espen Benjaminsen, MD, PhD, Epen.benjaminsen@nordlandssykehuset.no

    Espen Benjaminsen, MD, PhD

    Not yet recruiting
  • Vestre Viken Hospital

    Drammen, Buskerud, 3004

    Kari Anne Bjørnarå, MD, PhD, kari.anne.bjornara@vestreviken.no

    Kari Anne Bjørnarå, MD, PhD

    Not yet recruiting
  • Førde Hospital

    Førde, Vestland, 6812

    Aliaksei Labusau, MD, PhD, aliaksei.labusau@helse-forde.no

    Aliaksei Labusau, MD, PhD

    Not yet recruiting
  • Haugesund Hospital

    Haugesund, Rogaland, 5528

    Roelfien Ida HøgenEsch, MD, PhD, roelfien.ida.hogenesch@helse-fonna.no

    Roelfien Ida HøgenEsch, MD, PhD

    Not yet recruiting
  • Akershus University Hospital

    Lørenskog, Akershus, 1478

    Krisztina Kunszt Johansen, MD, PhD, krisztina.johansen@ahus.no

    Krisztina Kunszt Johansen, MD, PhD

    Not yet recruiting
  • Molde Hospital

    Molde, Møre og Romsdal, 6412

    Eldbjørg Hustad, MD, PhD, Eldbjorg.Hustad@helse-mr.no

    Eldbjørg Hustad, MD, PhD

    Not yet recruiting
  • Oslo University Hospital

    Oslo, Oslo, 0450

    Lasse Pihlstrøm, MD, PhD, lasse.pihlstrom@medisin.uio.no

    Lasse Pihlstrøm, MD, PhD

    Recruiting
  • Østfold Hospital

    Sarpsborg, Østfold fylke, 1714

    Gabriela Fortes, MD, Gabriela.Fortes@so-hf.no

    Gabriela Fortes, MD

    Not yet recruiting
  • University Hospital of North Norway

    Tromsø, Troms, 9019

    Hallvard Lilleng, MD, PhD, Hallvard.Lilleng@unn.no

    Hallvard Lilleng, MD, PhD

    Not yet recruiting

Other trials in Norway

About this study

Official title: D-SPARK: A Randomized Double Blind Clinical Trial of D-Serine for Modifying Parkinson's Disease Progression

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.

Read more

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.

Read the detailed description

The study design is a randomized, double-blind, placebo-controlled trial.

The trial consists of 3 stages followed by a washout period.

  • Screening and antiparkinsonian treatment optimization: --- Potential participants will be screened for eligibility and consented for participation. Treatment of Parkinson's disease with dopaminergic drugs will be initiated/adjusted until an optimal, stable effect of treatment is established. This treatment regimen will be maintained throughout the first 32 weeks of the intervention stage, after which changes will be allowed. If an optimal, stable dose is not achieved during screening, these participants will not proceed further and will not be included in the study.
  • Intervention stage: --- Participants will undergo randomization and will be assigned to receive either placebo or D-serine during different portions of the intervention phase. Participants will receive study drug (placebo or D-serine) for a total of 58 weeks. Thirty-two weeks after starting study drug, participants may have their dopaminergic drugs adjusted, if necessary.
  • Washout stage:
  • Upon completion of the intervention period, participants will discontinue study drug and will be followed for an additional 12 weeks. A final study visit will occur 12 weeks after discontinuation of study drug.
Being tested
D-serine, Placebo
Keywords
Serine, Parkinsons disease, D-serine
Medical subject headings
Parkinson Disease

What participants receive

What participants receive. In a randomised study each person is assigned to one group by chance.

  • D-serineDietary supplement

    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.

  • PlaceboDietary supplement

    Placebo 2 x oral capsules administered twice daily.

Study groups in NCT07312110
Study groupRoleWhat they receive
Early-startActive comparatorParticipants in this group will receive D-serine at an earlier time point than the placebo group. All participants will receive placebo and D-serine at different parts of the study.
Receives: Dietary Supplement: D-serine; Dietary Supplement: Placebo
Delayed-startPlacebo comparatorParticipants in this group will receive D-serine at a later time point than the early-start group. All participants will receive placebo and D-serine at different parts of the study
Receives: Dietary Supplement: D-serine; Dietary Supplement: Placebo

What is being measured

The primary outcome is the main question the study is designed to answer.

  1. Change in MDS-UPDRS Total Score (sum of Parts I-III).

    Difference between treatment groups (DSR vs placebo) in mean change from baseline to Week 26 in Movement Disorder Society Unified Parkinson's Disease Rating Scale (MDS-UPDRS) Total Score (sum of Parts I-III), assessed in all randomized participants under a treatment-policy strategy. MDS-UPDRS Part III tested in the OFF-medication state.

    MDS-UPDRS sum of part I-III: Clinical rating scale of motor and non-motor symptoms of Parkinson's Disease. Part I (13 items; Score 0-52) examines non-motor experiences, Part II (13 items; Score 0-52) examines motor experiences of daily living, Part III (33 items; Score 0-132) examines the cardinal motor disabilities. Each Part has 0-4 ratings, where 0 (no problems) to 4 (severe problems) and scores for each part are summed to calculate the total score which ranges from 0-236. Higher scores represent a worse outcome.

    Measured: 26 weeks.

Secondary outcomes (4)
  1. Change in mean striatal binding ratio (SBR) of the putamen bilaterally, measured by [¹²³I] FP-CIT Single-Photon Emission Computed Tomography (SPECT) Imaging of the Dopamine Transporter (DaT-scan).

    Difference between treatment groups (DSR vs Placebo) in mean change from baseline to Week 26 in the mean striatal binding ratio (SBR) of the putamen, bilaterally, as measured by [¹²³I] FP-CIT Single-Photon Emission Computed Tomography (SPECT) Imaging of the Dopamine Transporter (DaT-scan). Assessed in all randomized participants under a treatment-policy strategy.

    Measured: 26 Weeks.

  2. Change in MDS-UPDRS part III score.

    Difference between treatment groups (DSR vs placebo) in mean change from baseline to Week 26 in Movement Disorder Society Unified Parkinson's Disease Rating Scale (MDS-UPDRS) part III, assessed in all randomized participants under a treatment-policy strategy. MDS-UPDRS Part III tested in the OFF-medication state.

    MDS-UPDRS part III: Clinical rating scale of motor symptoms of Parkinson's Disease (33 items; Score 0-132). Higher scores represent worse outcomes.

    Measured: 26 Weeks.

  3. Change in EQ-5D-5L index value.

    Difference between treatment groups (DSR vs placebo) in mean change from baseline to Week 26 in the EQ-5D-5L index value, assessed in all randomized participants under a treatment-policy strategy. The scale measures quality of life on a 5-component scale with severity ranging from 0-5. An index from these is calculated based on country specific reference data and ranges from 0 to 1. Higher index score indicates a better outcome.

    Measured: 26 Weeks.

  4. Change in CVLT-II total Score and sub-scores.

    Difference between treatment groups (DSR vs placebo) in mean change from baseline to Week 26 in the California Verbal Learning Test version II (CVLT-II; Total Score and Sub-scores individually), assessed in all randomized participants under a treatment-policy strategy.

    CVLT-II: Verbal learning test assessing short delay and long delay recall and recognition. Separated into: Total score: Immediate Recall (sum of List A tests 1-5). Sub-scores: Short Delay Free Recall, Short Delay Cued Recall, Long Delay Free Recall, Long Delay Cued Recall, Long Delay Recognition, Forced Recognition.

    Higher CVLT-II scores indicate a better outcome.

    Measured: 26 Weeks.

Timeline

From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.

  1. First posted31 Dec 2025
  2. Study start20 Jan 2026
  3. Primary completionMar 2028 (estimated)
  4. Study completionDec 2028 (estimated)

Resources

More details

For doctors and researchers: how the study is designed, who runs it, and its registry IDs.

Study design
Study type
Interventional
Phase
Phase 2
Primary purpose
Treatment
Allocation
Randomised
Intervention model
Crossover
Model description
All participants will be assigned to placebo and D-serine at different time periods during the course of the study.
Masking
Triple blind
Who is masked
Participant, Care provider, Investigator
Enrolment
100 participants (estimated)
IDs, dates and publications
ClinicalTrials.gov ID
NCT07312110
Sponsor's protocol ID
REK: 929216
Acronym
D-SPARK
Status last verified
Jan 2026
First submitted
21 Nov 2025
Last updated
4 Jun 2026
Results posted
No
Data monitoring committee
Yes
FDA-regulated drug
No
FDA-regulated device
No
Individual data sharing
Yes: Individual participant data in pseudonomized format will be shared with collaborators for analysis based on data tranfer agreements adhering to the Eu's General Data Protection Regulation (GDPR).

Questions about this trial

What is this clinical trial studying?

A Phase 2 study testing D-serine in people with Parkinson s Disease and Parkinson Disease (PD), run by Haukeland University Hospital at 11 sites in Norway.

The full registered description is in the About this study section and the official record.

Who may be eligible to take part?

The sponsor lists 5 inclusion and 13 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.

Is this clinical trial currently recruiting?

The record says: looking for participants now, as of the sponsor's last update on 4 Jun 2026. Status can change between updates, so confirm with the study contact before making plans.

Where is the study taking place?

The record lists 11 sites in Norway. Whether a site is taking part right now should be confirmed with that site. See every site.

What are the possible benefits and risks?

They depend on the study and the treatment, and no study can promise a benefit. Some participants in this study may receive a placebo. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.

What does this phase mean?

Phase 2 studies give the treatment to a larger group to see whether it has the intended effect and to keep checking safety.

Not every study follows the same path, and some studies (observational studies, device studies) have no phase.

Are results available for this study?

This study is still under way. Results are not available in the source record yet.

How can a doctor refer a patient or contact the research team?

Contact Charalampos Tzoulis, MD, PhD (55975061 ext. +47, charalampos.tzoulis@helse-bergen.no), or a site near the patient. AzTrials does not enrol participants or take referrals.

What does the primary outcome measure?

Change in MDS-UPDRS Total Score (sum of Parts I-III). (time frame: 26 weeks.). It is what the study was designed to measure, not a finding.

Where can I read the original study information?
Does a listing mean the treatment is approved or proven to work?

No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.

How often is this information updated?

AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 4 Jun 2026.

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