Evidence map›Paper›PMID 41708985›Full record

ArticleJournal of neurology2026

Protocol of ASPro-PD: a phase 3 trial of ambroxol to slow progression in genetically stratified Parkinson's disease.

Marco Toffoli, Elisa Menozzi, Mairead Cullen, Kashfia Chowdhury, Saiam Ahmed, Nick Freemantle, Joy Duffen, Richard K Wyse, Simon R W Stott, Helen Matthews and 9 more

Abstract readClinical Trial Protocol
PubMed Full text at PMC Publisher
In one paragraph

Article in Journal of neurology, 2026. The graph could read no effect estimate from its abstract, so it casts no vote on the map. Cited by 7 papers.

0numbers the graph read from it
0cells of the map it votes in
7citing papers in PubMed
–field-weighted citation impact
1 · What the graph read from it

What it found

Each row is one number read from the abstract, on the scale the paper reported it, with its interval. Left of the dashed line favours the treatment, right favours the comparator. Under each row is the sentence it came from. New to these charts? A ten-minute tutorial.

The abstract states no effect estimate the extractor could read, or names no intervention and outcome on the map, so this paper lights no cell and moves no belief. It is still indexed, cited and linked below.

2 · The registry

The trial behind it

Trials whose registry record cites this paper, or whose number appears in the abstract. A trial that started after this paper was published is citing it as background, not reporting it.

Neither the registry nor the abstract names a trial number. If this is a trial report, that itself is worth knowing.

3 · Its place in the literature

Who cites it

7 citing papers in PubMed.

  1. Does genetic testing remain relevant in advanced Parkinson's disease?Journal of neural transmission (Vienna, Austria : 1996) · 2026
    Review
  2. Review
  3. Review
  4. Review
  5. Article
  6. Clinical Trials in GBA1-Associated Parkinson's Disease: A Need for Molecular Classification.Movement disorders : official journal of the Movement Disorder Society · 2026
    Article
  7. Review
4 · The record

Corrections and comments

PubMed lists nothing against this paper. Absence here is not a guarantee, only a check that was made.

5 · Who and what money

Authors and funding

19 authors.

Marco ToffoliDepartment of Clinical and Movement Neurosciences, UCL Queen Square Institute of Neurology, University College London, London, nW3 2Pf, UK.
Elisa MenozziDepartment of Clinical and Movement Neurosciences, UCL Queen Square Institute of Neurology, University College London, London, nW3 2Pf, UK.
Mairead CullenUCL Comprehensive Clinical Trials Unit, Institute of Clinical Trials and Methodology, University College London, London, UK.
Kashfia ChowdhuryUCL Comprehensive Clinical Trials Unit, Institute of Clinical Trials and Methodology, University College London, London, UK.
Saiam AhmedUCL Comprehensive Clinical Trials Unit, Institute of Clinical Trials and Methodology, University College London, London, UK.
Nick FreemantleUCL Comprehensive Clinical Trials Unit, Institute of Clinical Trials and Methodology, University College London, London, UK.
Joy DuffenCure Parkinson's, 120 New Cavendish Street, London, W1W 6XX, UK.
Richard K WyseCure Parkinson's, 120 New Cavendish Street, London, W1W 6XX, UK.
Simon R W StottCure Parkinson's, 120 New Cavendish Street, London, W1W 6XX, UK.
Helen MatthewsCure Parkinson's, 120 New Cavendish Street, London, W1W 6XX, UK.
David DexterCure Parkinson's, 120 New Cavendish Street, London, W1W 6XX, UK.
Felicia IkejiUCL Comprehensive Clinical Trials Unit, Institute of Clinical Trials and Methodology, University College London, London, UK.
Julie MossUCL Comprehensive Clinical Trials Unit, Institute of Clinical Trials and Methodology, University College London, London, UK.
Paul WattsNeurology Department, Royal Free Hospital, London, UK.
Tom FoltynieDepartment of Clinical and Movement Neurosciences, UCL Queen Square Institute of Neurology, University College London, London, nW3 2Pf, UK.
Karl KieburtzDepartment of Neurology, University of Rochester Medical Center, Rochester, NY, USA.
Olivier RascolDepartments of Clinical Pharmacology and Neurociences, Clinical Investigation Center CIC14366 and NS-Park/F-CRIN Network, Toulouse University Hospital, University of Toulouse 3 and INSERM, Toulouse, France.
Werner PoeweDepartment of Neurology, Medical University Innsbruck, Innsbruck, Austria.
Anthony H V SchapiraDepartment of Clinical and Movement Neurosciences, UCL Queen Square Institute of Neurology, University College London, London, nW3 2Pf, UK. a.schapira@ucl.ac.uk.

Funding

No grant is acknowledged in the PubMed record.

6 · The paper itself

Abstract

introductionGenetic studies have identified the GBA1 gene as a significant genetic risk factor for Parkinson's disease (PD), with 10-15% of PD patients carrying GBA1 variants. GBA1 variants affect the glucocerebrosidase (GCase) enzyme, often leading to reduced GCase activity and associated altered lysosomal function, implicated in PD pathogenesis. Ambroxol, a small molecule widely used for respiratory diseases, has emerged as a potential therapeutic agent for PD, acting by increasing GCase activity. A phase 2 trial demonstrated ambroxol's safety and efficacy in penetrating cerebrospinal fluid (CSF) and engaging with its target in PD patients, including those with GBA1 variants.

methodsWe present the protocol of the ASPro-PD trial, a phase 3, multicentre, randomised, double-blind, placebo-controlled trial, aimed at evaluating whether high-dose ambroxol improves motor and non-motor function in PD patients. The trial will enrol 330 PD patients with confirmed GBA1 status and the primary outcome will be the combined score of parts I, II, and III of the Movement Disorders Society-Unified Parkinson's Disease Rating Scale (MDS-UPDRS). The secondary outcomes include safety, impact on PD symptoms, and quality of life. Mechanistic and exploratory outcomes include biomarkers related to GCase activity, blood, and CSF biomarkers.

conclusionsThis trial is the largest to date to study the effect of ambroxol in PD, utilise a genetically stratified PD population and will provide robust estimates of the efficacy of ambroxol in slowing PD clinical progression.

Indexed as

AmbroxolExpectorantsGlucosylceramidaseParkinson DiseaseClinical Trials, Phase III as TopicDisease ProgressionDouble-Blind MethodFemaleHumansMaleMiddle AgedMulticenter Studies as TopicRandomized Controlled Trials as TopicAmbroxolExpectorantsGBA protein, humanGlucosylceramidaseAmbroxolclinical trialGBA1Parkinson

Identifiers

PMID41708985
PMCPMC12916515

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Registered trials

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Read under generation 80e0d062 · epoch 390. Bibliography from PubMed, PubMed Central and OpenAlex; grants from NIH RePORTER; trial links from ClinicalTrials.gov; estimates, votes and beliefs from the OpenQuestion graph.