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NCT05558787: AADCTDC
AADC/TDC in Advanced Parkinson's Disease
trial in Parkinson Disease in 48 participants. Completed in 14 August 2024.
14 August 2024
Quick facts
| Lead sponsor | Radboud University Medical Center |
|---|---|
| Status | Completed |
| Study type | OBSERVATIONAL |
| Enrollment | 48 |
| Start date | 28 June 2023 |
| Primary completion | 14 August 2024 |
| Estimated completion | 14 August 2024 |
| Sites | 1 location across Netherlands |
Conditions studied
- Parkinson Disease — all drugs for Parkinson Disease →
Sponsor
Radboud University Medical Center
Who can join
25 and older, any sex, with Parkinson Disease. Patients with the condition only — healthy volunteers not accepted.
Sponsor's own description
Rationale: Many persons with Parkinson's disease (PD) develop a progressive resistance to levodopa, which is the pharmacological mainstay of PD treatment. Recently, two enzymatic pathways have been identified that could be (partially) responsible for this: 1) breakdown of levodopa by bacterial tyrosine decarboxylase (TDC), an enzyme which normally decarboxylates dietary tyrosine but which is also able to decarboxylate levodopa. Accumulation of bacterial TDC in the small intestine, such as in the context of small-intestinal bacterial overgrowth (SIBO) - for which persons with PD are at increased risk - has the potential to prematurely metabolize levodopa, hence limiting its bioavailability and effect. 2) paradoxical induction of activity of the enzyme aromatic L-amino acid decarboxylase (AADC) in chronic users of levodopa combined with a peripheral decarboxylase inhibitor, also leading to a premature breakdown of levodopa and limitation of its bioavailability and effect. Primary objective: in a cross-sectional sample of advanced (≥5 years) Parkinson's disease determining the prevalence of increased bacterial TDC activity in feces, and the prevalence of increased AADC activity in serum. Secondary objective: correlating these biomarkers to clinical parameters, correlating composition of the microbiome to TDC activity, to the presence of levodopa resistance, and to factors related to socio-economic status. Study design: using feces, serum and urine samples and clinical data from n=50 participants, the relevant enzymes' activity will be measured and the composition of the gut microbiome will be determined. These will be correlated to the clinical and demographic parameters.
Publications & conference data
1 peer-reviewed publication reference this trial (live from Europe PMC):
-
From the Gut to the Brain: Is Microbiota a New Paradigm in Parkinson's Disease Treatment?
Vilela C, Araújo B, Soares-Guedes C, Caridade-Silva R, et al · · 2024 · cited 7× · PMID 38727306 · DOI 10.3390/cells13090770
Verify or expand the search:
- PubMed search for NCT05558787
- Europe PMC full search
- ASCO Meeting Library
- ESMO Meeting Library
- bioRxiv preprints
- medRxiv preprints
- Google Scholar
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Verify against primary sources
- ClinicalTrials.gov — authoritative US registry record
- WHO ICTRP — international registry index
- EU Clinical Trials Register
- Sponsor press releases (Google)
- Trial protocol + status: ClinicalTrials.gov NCT05558787 (US National Library of Medicine, public domain)
- Publications: Europe PMC API search by NCT ID, retrieved 10 June 2026
- Drug + disease cross-links: matched in real time against Drug Landscape's normalised drug + company + condition tables
- Sponsor: as reported to ClinicalTrials.gov by Radboud University Medical Center
- Last refreshed: 19 August 2024
Drug Landscape aggregates and links these public records for informational use only. Always verify against the primary source before clinical or regulatory decisions. Canonical URL: https://druglandscape.com/trial/NCT05558787.
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