# LIXIPARK Trial

**Type:** Phase 2 randomized controlled trial  
**Drug:** Lixisenatide (GLP-1 receptor agonist)  
**Indication:** Early Parkinson's disease  
**Status:** Completed, published NEJM April 2024  
**Primary Endpoint:** MDS-UPDRS Part III motor score at 12 months — MET (statistically significant)  

## Design
- **N:** 156 patients (75 lixisenatide, 75 placebo; some sources report 150)
- **Duration:** 12 months
- **Population:** Early Parkinson's disease (<3 years since diagnosis)
- **Blinding:** Double-blind
- **Delivery:** Daily subcutaneous injection

## Results
**Primary Endpoint (12 months):**
- Placebo: MDS-UPDRS Part III worsened +3.04 points (disease progression)
- Lixisenatide: Remained at baseline (0 change)
- Between-group difference: Statistically significant
- **Interpretation:** Lixisenatide halted motor symptom progression over 12 months

**Safety:**
- >50% of lixisenatide patients: significant GI side effects (nausea, vomiting)
- >1/3 required dose reduction due to GI tolerability
- Safety profile is major practical concern for real-world use

## Limitations
- Phase 2 (not Phase 3 — not definitive)
- 12 months (shorter than exenatide Phase 3 at 96 weeks)
- No DaT-SPECT brain imaging to confirm neuroprotection vs symptomatic benefit
- Off-label use NOT recommended pending Phase 3 confirmation

## Mechanistic Context
Holscher 2024 review identifies lixisenatide as having "strongest neuroprotective effect" among GLP-1 agonists in clinical trials, correlating with BBB penetrance via adsorption transcytosis. This may explain divergence from exenatide Phase 3 failure, where CSF analysis showed insufficient drug reaching substantia nigra.

## Publication
- **Journal:** New England Journal of Medicine
- **Date:** April 4, 2024
- **DOI:** 10.1056/NEJMoa2312323
- **Preliminary results:** Presented at 2023 International Parkinson and Movement Disorder Society congress, Copenhagen

## Follow-up Status
No Phase 3 funding announced as of May 2026. Exenatide Phase 3 failure (Lancet February 2025) may have chilled further GLP-1 Parkinson's trial investment.

## Timeline
- **2023-09** — Preliminary results presented at International Parkinson and Movement Disorder Society congress, Copenhagen
- **2024-04-04** — Full results published in NEJM, primary endpoint met with statistical significance
- **2024-2026** — No Phase 3 funding materialized despite positive Phase 2 results