---
title: "AB-1005 (GDNF gene therapy): Parkinson's Drug Pipeline"
description: An experimental one-time brain gene therapy designed to deliver a nerve-protecting growth factor (GDNF). It is in early safety testing; whether it helps is unknown.
canonical_url: "https://parkinsonspathways.com/pipeline/ab-1005-gdnf-gene-therapy"
development_stage: "Phase 1: first human safety tests"
last_updated: 2026-06-01
source: "Parkinson's Pathways"
---
# AB-1005 (GDNF gene therapy)

**Stage:** Phase 1b  ·  **Type:** Disease-modifying

**Developer:** AskBio (a Bayer company)

**How it works:** A one-time gene therapy: a harmless virus is surgically delivered into the brain to make cells produce GDNF, a natural growth factor meant to support ailing dopamine neurons.

**Target:** GDNF growth-factor delivery

**Who it's for:** People with mild-to-moderate Parkinson's (small early-stage study).

**Key trials:** NCT04167540

**Last reviewed:** 2026-06-01


## What it is

AB-1005 uses a harmless virus to deliver the instructions for making GDNF, a growth factor that supports dopamine-producing neurons, directly into a region of the brain through neurosurgery. The aim is a durable, one-time effect rather than a daily pill.

## Where it stands

It has been studied in a small Phase 1b trial focused mainly on whether the surgery and the therapy are safe and feasible. Any move to larger, controlled trials depends on those early results.

## What the data shows so far

The Phase 1b study enrolled roughly a dozen people and was designed to assess safety and feasibility, not to prove benefit. Earlier attempts to deliver GDNF to the Parkinson's brain by other methods did not clearly beat placebo, which is an important cautionary backdrop.

## What families should know

This is very early, involves brain surgery, and is years from being widely available, if it works at all. Prior GDNF approaches struggled in controlled trials, so optimism should be measured.

## Caveats

Efficacy is unproven. This is a small safety-focused study. It requires neurosurgery. Earlier GDNF delivery methods failed to clearly beat placebo, so the approach remains unproven in Parkinson's.

## Timeline

_Most recent first._

- **2020-2023**, Phase 1b safety/feasibility study in Parkinson's conducted.

## Sources

- [AB-1005 study on ClinicalTrials.gov](https://clinicaltrials.gov/study/NCT04167540)

_Last reviewed: 2026-06-01._

## More

- [Back to the Parkinson's drug pipeline](https://parkinsonspathways.com/pipeline)
- [Browse all recruiting trials](https://parkinsonspathways.com/trials)