Actively Recruiting
A Study of the Safety and Tolerability of GA in the Treatment of Patients With Refractory Neuropathic Pain
Led by Beijing Tiantan Hospital · Updated on 2026-01-22
6
Participants Needed
1
Research Sites
13 weeks
Total Duration
On this page
AI-Summary
What this Trial Is About
Researchers are investigating a new treatment for refractory neuropathic pain, a condition where pain persists despite standard therapies. This study focuses on the anterior cingulate cortex's role in pain and its emotional aspects, testing a chemogenetic approach that uses a gene (hM4Di) delivered by a drug called GA combined with oral clozapine. The goal is to assess the safety, tolerability, and effectiveness of this novel treatment in patients who have not responded to conventional therapies. Participants receive an intracranial injection of GA containing the hM4Di gene targeting the anterior cingulate cortex. After a 14 to 28 day observation period, they undergo a dose-escalation phase for oral clozapine to find an effective dose. Once established, they take a fixed dose of clozapine daily for three months. This combined approach aims to inhibit specific neurons involved in pain processing. Throughout the study, participants are monitored for adverse events up to 28 weeks. Researchers assess pain improvement using scales like the visual analogue scale (VAS) and Brief Pain Inventory (BPI) at weeks 4, 8, and 12. Sleep quality, mood, anxiety, and quality of life are also evaluated using standardized questionnaires. Additional tests measure immune response and drug levels in various body fluids. The study runs from screening through treatment and follow-up, with close observation of safety and effectiveness.
CONDITIONS
Brief Title
A Study of the Safety and Tolerability of GA in the Treatment of Patients With Refractory Neuropathic Pain
Who Can Participate
Eligibility Criteria
You may qualify if you...
- Patients aged 18 to 65 years with a confirmed diagnosis of neuropathic pain, including diabetic peripheral neuropathy, trigeminal neuralgia, or post-stroke pain
- Have undergone at least 3 months of conventional medical therapy without symptom relief or tolerance
- Have completed a full course of treatment with at least two first-line medications
- Mean pain score of 4 cm or higher on the visual analogue scale (VAS) or 4 points or higher on the numerical rating scale (NRS) within one week of baseline
- Stable analgesic regimen for at least 30 days before enrollment and agree not to change medication type or dose during the study effectiveness assessment
- Voluntarily consent to participate and sign informed consent
- Stable neurological status as assessed through motor, sensory, and reflex functions
- Able to comply with study protocol, visit schedules, and medication administration
- Agree to use effective contraception if of childbearing potential, with no plans to have children or donate sperm/eggs during the study period
You will not qualify if you...
- Amputation due to diabetes or large (3 cm or more) and/or gangrenous ulcers on lower limbs in diabetic peripheral neuropathy patients
- Progressive neurological disorders such as multiple sclerosis, chronic inflammatory demyelinating polyneuropathy, brain/spinal cord tumors, or neurodegenerative disorders
- Severe cardiopulmonary diseases including unstable angina, myocardial infarction, severe arrhythmia, or recurrent asthma attacks
- Malignant tumors of the central nervous system or other systems
- Conditions affecting surgery participation, such as coagulation disorders, bleeding tendencies, severe diabetes, or peripheral vascular disease
- Current use of anticoagulants that cannot be stopped
- Local or systemic infection at surgical access site
- History of prior intracranial surgery except minimally invasive diagnostic procedures
- Severe psychiatric symptoms or significant suicidal tendencies
- Severe dysfunction of liver, kidney, or heart as defined by specific laboratory and clinical criteria
- Abnormal laboratory values including low white blood cell or platelet counts, coagulation abnormalities, or high blood AAV antibody titers
- Use of drugs causing granulocyte deficiency or myelosuppression
- Contraindications or allergies to clozapine or related medications
- Gastrointestinal diseases or surgeries affecting drug absorption or metabolism
- Previous gene or cellular therapy
- History of alcohol or drug abuse
- Participation in other clinical trials or investigational treatments within 6 months
- Contraindications to MRI or functional MRI
- Clozapine-related serious adverse reactions during screening period
AI-Screening
AI-Powered Screening
Complete this quick 3-step screening to check your eligibility
Your Study Journey
Duration - 2 to 4 weeks
Participants are screened for eligibility to participate in the trial.
1 screening and enrollment visit
Duration - Approximately 3 to 4 months
Participants receive an intracranial injection of GA and are observed for 14 to 28 days, followed by a dose-escalation trial of oral clozapine. After determining an effective dose, participants continue with a fixed oral dose of clozapine for three months.
Multiple visits including initial injection observation and follow-ups during clozapine dosing
Duration - Up to 28 weeks
Participants are monitored for safety, tolerability, and effectiveness of the treatment, including assessments of pain, sleep quality, mood, and quality of life.
Regular visits for assessments up to 28 weeks
Trial Site Locations
Total: 1 location
1
Beijing Tiantan Hospital
Beijing, Beijing Municipality, China, 100070
Actively Recruiting
Research Team
Y
Yahui Zhu, Doctor
How is the study designed?
Study Type
INTERVENTIONAL
Masking
NONE
Allocation
NA
Model
SINGLE_GROUP
Primary Purpose
TREATMENT
Number of Arms
1
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