GA002 – A First-in-Class Gene Therapy for Epilepsy Enters Phase I/II Clinical Trial

GA002, a 1-class innovative drug, initiates a Phase I/II clinical trial for drug-resistant epilepsy, employing a precision gene-editing approach to silence abnormal neuronal discharges.

Introduction

Epilepsy is one of the most common neurological disorders worldwide, affecting approximately 50 million people globally. In China, an estimated 10 million people live with epilepsy, and approximately 30% of patients develop drug-resistant epilepsy — a condition that does not respond to standard anti-epileptic drugs (AEDs).

For patients with drug-resistant epilepsy, treatment options are limited. Surgical resection of the epileptogenic focus can be curative in some cases, but many patients are not candidates for surgery due to the location of the seizure focus or multiple foci.

GA002 represents a revolutionary approach to epilepsy treatment. Developed as a 1-class innovative drug, GA002 employs a precision gene-editing strategy to selectively silence abnormal neuronal discharges at their source — offering a potentially curative approach for patients with drug-resistant epilepsy.

Mechanism of Action

GA002 is a gene therapy delivered via adeno-associated virus (AAV) vector that targets the epileptogenic zone in the brain. The therapy employs a proprietary gene-editing system designed to:

• Silence hyperactive neurons — selectively reducing abnormal neuronal excitability
• Restore normal network activity — by modulating excitatory-inhibitory balance
• Achieve long-term seizure control — with a single administration
• Minimize off-target effects — through highly specific targeting

The therapy is delivered via stereotactic injection directly into the epileptogenic zone, guided by advanced neuroimaging and electrophysiological mapping. This targeted delivery approach minimizes systemic exposure and maximizes therapeutic efficacy at the site of seizure generation.

The Challenge of Drug-Resistant Epilepsy

Drug-resistant epilepsy is defined as failure of adequate trials of two tolerated, appropriately chosen anti-epileptic drug schedules (whether as monotherapy or in combination) to achieve sustained seizure freedom.

For these patients:

• Quality of life is severely impaired — seizures interfere with daily activities, employment, and social functioning
• Risk of sudden unexpected death in epilepsy (SUDEP) is significantly elevated
• Cognitive and psychiatric comorbidities are common and often worsened by AEDs
• Healthcare utilization is high — frequent emergency department visits and hospitalizations

GA002 offers a new hope for these patients — addressing the underlying pathophysiology rather than simply suppressing symptoms.

Preclinical Evidence

Preclinical studies of GA002 demonstrated:

• Complete seizure freedom in 80% of treated animals in a chronic epilepsy model
• Significant reduction in seizure frequency in the remaining animals
• No significant off-target toxicity or adverse effects on normal brain function
• Durable effect lasting throughout the 12-month study period
• No evidence of immunogenicity — suggesting the therapy is well-tolerated

Phase I/II Clinical Trial Design

The Phase I/II clinical trial is a first-in-human, open-label, dose-escalation study conducted at multiple leading neuroscience centers across China.

Parameter	Details
Patient population	Drug-resistant focal epilepsy (≥2 failed AEDs)
Number of patients	30 patients
Dose cohorts	3 dose levels (low, medium, high)
Administration	Single stereotactic injection
Primary endpoint	Safety and tolerability at 6 months
Secondary endpoints	Seizure frequency reduction, quality of life, cognitive function

Expected Outcomes

Based on preclinical data, the trial aims to demonstrate:

• Favorable safety profile — no serious adverse events related to the therapy
• Clinically meaningful seizure reduction — ≥50% reduction in seizure frequency in the majority of patients
• Durable response — sustained seizure control beyond the 12-month observation period
• Improvement in quality of life — reduced seizure burden and improved daily functioning

Significance for Chinese Neuroscience

GA002 represents several important milestones:

• First gene therapy for epilepsy — in China and one of the first globally
• 1-class innovative drug — demonstrating China's capability to develop breakthrough therapies for neurological disorders
• Addressing a major unmet need — drug-resistant epilepsy affects millions worldwide
• Platform technology — the gene-editing approach may be applicable to other neurological disorders with focal pathology

Future Directions

Following the Phase I/II trial, the research team plans to:

• Expand to larger patient cohorts in a Phase III registrational trial
• Explore applications in pediatric epilepsy and other epilepsy syndromes
• Investigate combination approaches with existing anti-epileptic drugs
• Develop next-generation delivery systems to improve targeting and reduce invasiveness