Exenatide

Recently stopped or failed

A repurposed diabetes drug that raised hopes after a small earlier study, but failed to slow Parkinson's in a larger Phase 3 trial reported in 2024.

• Stage: Phase 3 failed (2024)
• Type: Disease-modifying
• Developer: Academic / investigator-led (a repurposed diabetes drug)
• Target: GLP-1 receptor
• How it works: A GLP-1 diabetes drug that was hoped to protect brain cells in Parkinson's.
• Who it's for: People with Parkinson's (Phase 3 in moderate disease).
• Why it stopped: The definitive Phase 3 trial (Exenatide-PD3, 2024) found no benefit over placebo, so the Parkinson's program did not proceed.
• Key trials: NCT04232969
• Last reviewed: 2026-06-01

What it is

Exenatide is a GLP-1 diabetes drug. A small 2017 trial generated excitement by suggesting it might slow Parkinson's, making it one of the most-watched repurposing stories in the field.

Where it stands

The definitive Phase 3 trial (Exenatide-PD3) reported in 2024 that it did not slow Parkinson's. The program for Parkinson's did not move forward on that basis.

What the data shows so far

Exenatide-PD3 enrolled around 194 people for nearly two years and found no difference between exenatide and placebo on the Parkinson's motor scale: a clear negative result that overrode the earlier, much smaller positive study.

What families should know

This is an important cautionary tale: a promising small study did not hold up in a larger, rigorous trial. It is why the field insists on confirmatory Phase 3 data before claiming a drug slows Parkinson's. (The related drug lixisenatide had a small positive Phase 2, so the GLP-1 question isn't fully closed, but exenatide itself failed.)

Caveats

Failed its Phase 3 primary endpoint. The earlier positive Phase 2 was small and did not replicate. Listed here for transparency, not as a treatment to pursue.

Timeline

Most recent first.

• 2024, Phase 3 (Exenatide-PD3) finds no benefit.
• 2017, Small Phase 2 suggests a possible benefit.

Sources

• Exenatide-PD3 on ClinicalTrials.gov

Last reviewed: 2026-06-01. Back to the Parkinson's drug pipeline