Gene therapy injection tested for rare nerve disease
NCT ID NCT05361031
First seen Jun 24, 2026 · Last updated Jun 27, 2026 · Updated 1 time
Early CMT1A gene therapy study offers a small but hopeful signal
This study tested Engensis (VM202) in 12 adults with CMT1A. The official results suggest the treatment was generally tolerated, and some important disease measures improved over time, including the main neuropathy score. But this was still a small early study, and everyone received the treatment. So this is not proof yet. It is more like seeing the first light at dawn — not full daylight, but enough to show the road may continue.
This was an early Phase 1/2a study for adults with genetically confirmed CMT1A. All 12 participants received Engensis injections into weakened leg muscles and were followed for about 270 days.
Because there was no placebo group, this study was not designed to give a final answer. Its job was more humble than that. Think of it like dipping a toe into the water before crossing the river: first you ask, “Does this seem safe?” and only later do you ask, “How far can this really take us?”
On safety, the official results were reassuring for such an early trial. A few adverse events were reported, including injection-site itching, peripheral edema, pneumonia, and uterine leiomyoma, each in one participant. The sponsor described the treatment as well tolerated, and the safety goals of the study were met.
That matters, because in early-stage research, safety is the first gate. Before a treatment can try to help people more, it has to show it can enter the room without breaking the furniture.
The most encouraging signal came from the CMT Neuropathy Score version 2 (CMTNS-v2). On average, the score improved from 15.58 at baseline to 13.42 at day 270, which means symptoms looked less severe over time.
Other measures also moved in a hopeful direction. The Functional Disability Score improved on average, and the Overall Neuropathy Limitation Score for the legs also showed a modest improvement. The 10-meter walk test, however, changed very little, so walking speed did not clearly improve in this small study.
In other words, the picture was not perfect, but it was not empty either. It was more like hearing a few clear notes from a piano in another room — not yet a full song, but enough to know someone may be playing.
The official results also included MRI muscle measurements and nerve testing, and those findings were more mixed. Still, the overall pattern gave the sponsor enough reason to describe the trial as promising.
So what should families and patients take from this?
The fairest answer is: hope, with caution.
This study was small. It was early. And without a placebo group, it cannot prove that Engensis works. But it did show a signal that may be worth following. In rare diseases like CMT1A, that matters. Sometimes progress does not arrive like a thunderclap. Sometimes it starts as a knock at the door.
Study facts
What this study's own registry entry says, in plain language.
- Phase
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Phase 1/2
Runs two stages together: safety and dose first, then whether the treatment works.
- Participants
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12 people
The number who actually took part.
- Started
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Sep 2020
- Finished
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Feb 2022
- Lead sponsor
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A company
The lead sponsor is a pharmaceutical, biotech, or medical-device company.
Who can take part
This study's own entry requirements. Only the study team can say for certain whether you qualify.
- Ages
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19 to 65 years
- Sex
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Anyone
- Healthy volunteers
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Not accepted
This study is not open to healthy volunteers. The entry requirements below say who it is open to.
Show the full entry requirements Hide the full entry requirements
Copied word for word from the study's registry entry, so the wording is the study team's rather than ours.
Inclusion Criteria: 1. Males or females ≥ 19 years of age and ≤ 65 years of age 2. Patients with confirmed diagnosis of CMT1A by genetic testing 3. Patients with mild to moderate severity assessed by Charcot Marie Tooth Neuropathy Score version 2 (CMTNS v2) with a score \> 2 and ≤ 20 4. Individuals with lower limb muscle weakness with minimum dorsiflexion or more 5. Individuals who voluntarily consented to participate in this study and signed the IRB approved informed consent form after listening to a description on the characteristics of this clinical study prior to all screening tests 6. Individuals who can comply with the requirements in the clinical study 7. In case of females of child bearing potential, those who test negative in a urine or serum pregnancy test at screening 8. Individuals who practice medically approved contraceptive methods throughout the clinical study Exclusion Criteria: 1. Patients with significant respiratory, circulatory, renal, gastrointestinal, hepatic, endocrine, hematologic, psychiatric disorders or other severe diseases, or alcohol or drug addiction who may develop safety issues or cause confusion in the interpretation of the clinical study results as determined by the principal investigator 2. Patients with other neuromuscular diseases or neuropathy-inducing factors: Patients with chronic alcohol addiction, undergoing anticancer chemotherapy, or taking neurotoxic drugs 3. Patients diagnosed with diabetes 4. Patients diagnosed with inflammatory bowel disease 5. Patients with a history of stroke or cerebral ischemic attack within 12 months prior to the screening date 6. Patients with a history of coronary artery disease, such as myocardial infarction and unstable angina pectoris, within 12 months prior to the screening date 7. Morbidly obese patients with body mass index (BMI) ≥ 37 8. Patients who underwent orthopedic surgery (corrective surgery for bone and ligament, artificial joint implantation, osteosynthesis, osteotomy, arthroscopic surgery) in the lower limbs within 6 months prior to the screening date 9. Patients who may be affected by the muscle strength measurement test due to ankle contracture or surgery 10. Patients with uncontrolled hypertension (if systolic blood pressure is ≥ 160 mmHg or diastolic blood pressure is ≥ 100 mmHg at screening) 11. Patients or patient's immediate family members (parents, siblings, offspring) with a history of malignant tumors within the last 5 years prior to the screening date, excluding basal cell carcinoma or squamous cell carcinoma that occurs on the skin (if it is determined that there is no possibility of relapse after resection), or with a family history of familial adenomatous polyposis (FAP) or hereditary nonpolyposis colorectal cancer (HNPCC) 12. Patients who have not completed a national cancer screening program applicable to their sex and age (if it cannot be confirmed that the relevant test was received at a national cancer screening center or a recognized screening center) However, if it is confirmed that the relevant test was received at a national cancer screening center or a recognized screening center during the screening period, and that the results were within normal range, the patients may participate in the clinical study. Common to males and females: If a patient is ≥ 50 years of age, the results of a colonoscopy within 5 years prior to the screening must be determined as being within normal range, and if adenomatous polyps are evident, the results of a colonoscopy within 1 year must be determined as being within normal range (inflammatory polyps or hyperplastic polyps are included in the normal range). If a patient is ≥ 40 years of age, the results of a gastroscopy within 2 years prior to the screening must be within normal range. If a patient is ≥ 54 years of age and has a 30 pack-year history of smoking or more, the results of a low-dose chest CT within 2 years prior to the screening must be within normal range. In case of liver cancer, carriers of hepatitis B or hepatitis C virus and patients with hepatic cirrhosis fall under the exclusion criteria. Females: For females ≥ 40 years of age, normal range findings must be confirmed in a mammogram within 2 years. For females ≥ 20 years of age, normal range findings must be confirmed in a Pap smear within 2 years. 13. Patients diagnosed with active pulmonary tuberculosis 14. Patients with HBV or HCV 15. Patients who test positive in human immunodeficiency virus (HIV) antibody test 16. Patients in an immunosuppressive state due to treatments such as immunosuppressants, chemotherapy, and radiotherapy 17. Patients with a history of mental disease within 6 months prior to the screening date, which may interfere with participation in the study 18. Patients who must take medications, that are known to have significant drug interactions within 14 days after the first administration of the investigational product or deemed unsuitable by the investigator's judgment 19. Individuals who participated in another clinical study within 6 months before the time of screening 20. Individuals who have shown significant adverse events such as hypersensitivity reactions to the investigational product 21. Pregnant or breastfeeding females 22. Other individuals determined ineligible by the principal investigator to participate in the clinical study due to other reasons including clinical laboratory test results
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Conditions
The condition(s) this trial relates to.
As listed by the trial registrant
The condition terms exactly as the trial's registrant entered them.
Contacts and locations
Locations
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Samsung Medical Center, Seoul National University Hospital
Seoul, 06351, South Korea
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