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AAV-GAD

Phase 1

Parkinson's Disease | Gene therapy | Neurology |MeiraGTx Holdings plc|Last Updated: Sep 5, 2025

Success Probability

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Trial Design

RandomizedDouble-BlindNO_TREATMENT_CONTROLLEDDMC
Total Trials2
Total Enrollment27

FDA Designations

RMAT

Clinical trial landscape

AAV-GAD · 2 trials · 1 indication

Phase 1 2
NCT05894343Long-term Follow-up of Glutamic Acid Decarboxylase (GAD) Gene Transfer in Parkinson's DiseaseParkinson's Disease
ACTIVE NOT_RECRUITING13 Analytics
NCT05603312A Double-blind Study to Evaluate the Safety of Glutamic Acid Decarboxylase Gene Transfer in Parkinson's ParticipantsParkinson's Disease
COMPLETED14 Analytics
PHASE1ACTIVE NOT_RECRUITING
Long-term Follow-up of Glutamic Acid Decarboxylase (GAD) Gene Transfer in Parkinson's Disease
Parkinson's DiseaseUnlock trial analytics
PHASE1COMPLETED
A Double-blind Study to Evaluate the Safety of Glutamic Acid Decarboxylase Gene Transfer in Parkinson's Participants
Parkinson's DiseaseUnlock trial analytics

Study Endpoints

Primary Endpoints

Number of participants with study drug-related adverse events and serious adverse events
From study start until Month 60 post treatment
Incidence of Adverse Events Related to the Treatment
Baseline to Week 26

The primary outcome measure is the safety of treatment with AAV-GAD, assessed by the absence of IMP-related treatment-emergent adverse events.

Incidence of Serious Adverse Events Related to the Treatment
Baseline to Week 26

The primary outcome measure is the safety of treatment with AAV-GAD, assessed by the absence of IMP-related serious treatment-emergent adverse events.

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Study Design & Arms

AllocationRANDOMIZED
MaskingNONE
ModelPARALLEL
PurposeTREATMENT

Treatment Arms

ArmTypeDescription
Follow-up groupNO_INTERVENTIONParticipants who were randomized to immediate treatment in Study MGT-GAD-025 will transition directly to a long-term follow-up schedule to complete an additional 54 months of follow-up. All study participants are to be followed for 60 months after vector administration.
Active treatment groupEXPERIMENTALParticipants who were randomized to sham surgery in Study MGT-GAD-025 will transition to an active treatment schedule, including open-label bilateral treatment, upon confirmation of continued eligibility. Upon completion of the treatment period, participants will enter the long-term follow-up schedule to complete a total of 60 months of follow-up.
AAV-GAD Low DoseEXPERIMENTALEligible participants received bilateral infusion of AAV-GAD low dose into the STN
AAV-GAD High DoseEXPERIMENTALEligible participants received bilateral infusion of AAV-GAD high dose into the STN
Sham SurgerySHAM_COMPARATOREligible participants underwent a sham surgical procedure

Interventions

NameTypeDescription
AAV-GADGENETICBilateral infusion of AAV-GAD
AAV-GAD Low DoseGENETICBilateral infusion of AAV-GAD low dose
AAV-GAD High DoseGENETICBilateral infusion of AAV-GAD high dose
Sham SurgeryPROCEDURESham infusion
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Eligibility Criteria

Age Range25 Years to 86 Years
SexALL
Healthy VolunteersNo
Study Sites6

Inclusion Criteria: * Previously enrolled in Study MGT-GAD-025. Exclusion Criteria: * None

Countries:United States
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Recent Changes (Last 90 Days)

MEDIUMMay 26, 2026NCT05894343Phase: PHASE1/PHASE2 → PHASE1
LOWMay 24, 2026NCT05894343studyFirstPostDate: changed

Frequently asked questions about AAV-GAD

What is AAV-GAD used for in Parkinson's Disease?

AAV-GAD is an investigational gene therapy being studied for the treatment of Parkinson's Disease. It is designed to deliver the glutamic acid decarboxylase gene to the brain, with the goal of producing GABA, a neurotransmitter that may help regulate the overactive neurons associated with Parkinson's symptoms. It is currently in Phase 1 clinical development.

What does AAV-GAD target?

AAV-GAD targets the glutamic acid decarboxylase gene, which encodes the enzyme responsible for synthesizing GABA, an inhibitory neurotransmitter. By delivering this gene to the brain, the therapy aims to increase GABA production and reduce the excessive neuronal activity that contributes to Parkinson's Disease symptoms.

Who makes AAV-GAD?

AAV-GAD is being developed by MeiraGTx Holdings plc, a biopharmaceutical company traded on the NASDAQ under the ticker symbol MGTX. The company is conducting clinical trials to evaluate the safety and efficacy of this gene therapy for Parkinson's Disease.

What phase is AAV-GAD in?

AAV-GAD is currently in Phase 1 clinical development. It is an investigational therapy and has not been approved by the FDA. The drug has received a Regenerative Medicine Advanced Therapy (RMAT) designation from the FDA, which is intended to expedite the development and review of regenerative medicine therapies.

What clinical trials is AAV-GAD in?

AAV-GAD has been studied in two Phase 1 clinical trials. The first, NCT05603312, was a double-blind study evaluating safety in 14 participants with Parkinson's Disease and has been completed. The second, NCT05894343, is an active long-term follow-up study of 13 participants. Both trials were conducted in the United States.

Is AAV-GAD the same as glutamic acid decarboxylase gene transfer?

Yes, AAV-GAD is also referred to as glutamic acid decarboxylase gene transfer. The clinical trials for this therapy are titled to reflect this, such as 'A Double-blind Study to Evaluate the Safety of Glutamic Acid Decarboxylase Gene Transfer in Parkinson's Participants' and 'Long-term Follow-up of Glutamic Acid Decarboxylase (GAD) Gene Transfer in Parkinson's Disease'.