Exenatide once a week versus placebo as a potential disease-modifying treatment for people with Parkinson's disease in the UK: a phase 3, multicentre, double-blind, parallel-group, randomised, placebo-controlled trial
- Design
- Randomized trial · 194 participants · Intermediate outcome
- Match to healthy normal-weight adults aged 55–75
- Partial matchParticipants were selected for Parkinson's disease, not for obesity or diabetes, and were mostly older adults; so the population is closer to the target than metabolic trials, but the outcome (motor progression in PD) does not transfer to healthy people.
- Could weight loss explain it?
- UnlikelyNull result; weight loss not a plausible confounder of a null finding.
- Study tier
- Study tier 1Adequately powered phase 3 trial with the longest follow-up in this indication; robust null.
- Assessment
- Version 2 · curated · Sep 13, 2026
Study facts come from the paper. Population match, weight-loss explanation and study tier are our judgments, made against the reference group of healthy normal-weight adults aged 55–75.
A publicly funded phase 3 trial in 194 people with Parkinson's disease found no slowing of motor progression with weekly exenatide over two years. This is the strongest evidence to date against GLP-1 disease modification in Parkinson's.
01Findings
What the study reported
- Drugs
- Exenatide
- Dose
- 2 mg extended-release once weekly
- Route
- subcutaneous
- Treatment duration
- 96 weeks
- Comparator
- placebo
- Primary outcome
- MDS-UPDRS part III off-medication at 96 weeks
- Effect
- Adjusted difference 0.92 points (worse with exenatide; not significant)
- 95% confidence interval
- -1.56 to 3.39
- P value
- 0.47
- Follow-up
- 96 weeks
- Adverse events
- Serious adverse events 9% vs 11%; well tolerated.
- Limitations
- Auto-classified from abstract only; effect estimates, adverse events and limitations not extracted. Requires manual review.
Who was studied
- Age range
- 25-80
- Age min
- 25
- Sex distribution
- 29% female
- Obesity status
- not an entry criterion (not selected for weight)
- Diabetes status
- not an entry criterion
- Baseline condition
- Parkinson's disease, Hoehn and Yahr <= 2.5 on treatment
- Sample size
- 97
Study quality details
- Study design
- Randomized controlled trial
- Sample size
- 97
- Randomization
- yes
- Blinding
- double-blind
- Comparator
- placebo
- Follow up duration
- 96 weeks
- Outcome type
- intermediate
- Replication
- does not replicate the earlier phase 2 exenatide signal
- Consistency with other evidence
- not assessed (auto)
- Population applicability
- PARTIAL
- Statistical precision
- CI reported: 95% CI -1·56 to 3·39]
- Risk of bias
- low
- Funding conflicts
- no
- Peer review status
- yes
02Funding
Funding and conflicts
- Funding
- National Institute for Health Research (UK) and others; NIH intramural support listed
- Industry funded
- No
- Manufacturer
- None identified
- Sponsor role
- Academic sponsor; no manufacturer role stated.
- Author conflicts
- Lead author reports honoraria including from Novo Nordisk; trial publicly funded.
- Independent replication
- yes (independent of manufacturer)
Funding is shown on every study and never used to score it.
03Claims
Claims this study bears on
- GLP-1 receptor agonists slow progression of Parkinson's disease.Contradicts
Exenatide-PD3 phase 3 (n=194): no difference at 96 weeks.
04Source
The source, as retrieved
Abstract
[BACKGROUND] GLP-1 receptor agonists have neurotrophic properties in in-vitro and in-vivo models of Parkinson's disease and results of epidemiological studies and small randomised trials have suggested possible benefits for risk and progression of Parkinson's disease. We aimed to establish whether the GLP-1 receptor agonist, exenatide, could slow the rate of progression of Parkinson's disease. [METHODS] We did a phase 3, multicentre, double-blind, parallel-group, randomised, placebo-controlled trial at six research hospitals in the UK. Participants were aged 25-80 years with a diagnosis of Parkinson's disease, were at Hoehn and Yahr stage 2·5 or less when on dopaminergic treatment, and were on dopaminergic treatment for at least 4 weeks before enrolment. Participants were randomly assigned (1:1) using a web-based system with minimisation according to Hoehn and Yahr stage and study site to receive extended-release exenatide 2 mg by subcutaneous pen injection once per week over 96 weeks, or visually identical placebo. All participants and all research team members at study sites were masked to randomisation allocation. The primary outcome was the Movement Disorder Society-sponsored revision of the Unified Parkinson's Disease Rating Scale (MDS-UPDRS) part III score, off dopaminergic medication at 96 weeks, analysed in the intention-to-treat population using a linear mixed modelling approach. This study is registered with ISRCTN (14552789), EudraCT (2018-003028-35), and ClinicalTrials.gov (NCT04232969). [FINDINGS] Between Jan 23, 2020, and April 23, 2022, 215 participants were screened for eligibility, of whom 194 were randomly assigned to exenatide (n=97) or placebo (n=97). 56 (29%) participants were female and 138 (71%) were male. 92 participants in the exenatide group and 96 in the placebo group had at least one follow-up visit and were included in analyses. At 96 weeks, MDS-UPDRS III OFF-medication scores had increased (worsened) by a mean of 5·7 points (SD 11·2) in the exenatide group, and by 4·5 points (SD 11·4) points in the placebo group (adjusted coefficient for the effect of exenatide 0·92 [95% CI -1·56 to 3·39]; p=0·47). Nine (9%) participants in the exenatide group had at least one serious adverse event compared with 11 (11%) in the placebo group. [INTERPRETATION] Our findings suggest that exenatide is safe and well tolerated. We found no evidence to support exenatide as a disease-modifying treatment for people with Parkinson's disease. Studies with agents that show better target engagement or in specific subgroups of patients are needed to establish whether there is any support for the use of GLP-1 receptor agonists for Parkinson's disease. [FUNDING] National Institute for Health and Care Research and Cure Parkinson's.
Where this record came from
| Source | Retrieved | Identifier |
|---|---|---|
| pubmed | Sep 13, 2026 | 39919773 first ingestion |