How strong is the evidence for stem-cell therapy in Intellectual Disability?
ClinicalTrials.gov registrations alone cannot establish how strong the evidence is. Registry activity is active but still early, with limited late-phase registration: the registry holds 27 records, 11 completed, 4 at Phase 3 or 4, and 4 stopped early (15%). MSC-specific work accounts for 0 of those records. These counts describe research activity and maturity, not benefit, safety or certainty. Snapshot 2026-08-29.
What counts as a real result in Intellectual Disability
Credible outcomes need blinded standardised cognitive and adaptive-function assessment over a year, with a control group receiving the same educational and therapeutic input. Developmental change over that period is expected in children regardless of intervention.
What we can say from registrations alone
- Volume: 27 registered studies since 1995.
- Maturity: 4 confirmatory-phase records.
- Delivery: 11 completed; 4 terminated, withdrawn or suspended.
- Scale: median planned enrolment 38 participants, largest 380.
The completed studies
Completed does not mean published, and published does not mean positive. These are the finished records — the starting point for checking whether results ever appeared.
| Study | Phase | Status | Planned n | Lead sponsor | Start |
|---|---|---|---|---|---|
| NCT00176904 — Stem Cell Transplant for Inborn Errors of Metabolism | Phase 2, Phase 3 | Completed | 135 | Masonic Cancer Center, University of Minnesota | 1995-01 |
| NCT01043640 — Allogeneic Bone Marrow Transplant for Inherited Metabolic Disorders | Phase 2 | Completed | 46 | Masonic Cancer Center, University of Minnesota | 2009-12 |
| NCT01586455 — Human Placental-Derived Stem Cell Transplantation | Phase 1 | Completed | 43 | New York Medical College | 2013-04 |
| NCT00383448 — HSCT for High Risk Inherited Inborn Errors | Phase 2 | Completed | 38 | Masonic Cancer Center, University of Minnesota | 2006-09 |
| NCT03852498 — A Clinical Study to Assess the Efficacy and Safety of Gene Therapy for the Treatment of Cerebral Adrenoleukodystrophy (CALD) | Phase 3 | Completed | 35 | Genetix Biotherapeutics Inc. | 2019-01-24 |
| NCT01896102 — A Study of the Efficacy and Safety of Hematopoietic Stem Cells Transduced With Lenti-D Lentiviral Vector for the Treatment of Cerebral Adrenoleukodyst | Phase 2, Phase 3 | Completed | 32 | Genetix Biotherapeutics Inc. | 2013-08-21 |
What registrations cannot tell you
Whether results were positive. Whether they were published at all — a large share of registered studies never report outcomes, which biases what the literature appears to show. And whether the product a commercial clinic sells resembles the product studied: cell source, dose, processing and delivery route vary enormously between a registered protocol and an off-protocol injection.
How to use this when someone is selling you a treatment
Ask which specific registered study supports the offer, then compare its intervention description with your quote. If the answer is a general gesture at "Intellectual Disability research", you are being sold the field's activity rather than evidence about the product. The Provider Question Builder turns that gap into questions.
Frequently asked
How strong is the evidence for stem-cell therapy in Intellectual Disability?
ClinicalTrials.gov registrations alone cannot establish how strong the evidence is. Registry activity is active but still early, with limited late-phase registration: 27 registered records, 4 at Phase 3/4 and 4 stopped early (2026-08-29).
Has any stem-cell product been approved for this condition?
Look it up at source: regulators publish authorised products and indications. Registration of a trial, a licence to operate a clinic and product approval are three different things.
Why do clinics cite hundreds of studies?
Volume is the cheapest form of credibility. Ask instead for the controlled studies of the specific product, and read what outcome they measured.
Registry and literature counts retrieved 2026-08-29 (ClinicalTrials.gov API v2; PubMed E-utilities). Registration or publication volume measures research activity, not effectiveness or approval. Educational information — not medical advice; verify product, indication, legal pathway and evidence with an independent qualified physician. Page generated 2026-08-29. See our editorial standards.