What research stage is stem-cell therapy for Intellectual Disability at?
4 of 27 registered records carry a Phase 3 or Phase 4 label. The rest sit at earlier phases or carry no phase label at all. Snapshot 2026-08-29.
Phase distribution
| Phase label | Records | Share |
|---|---|---|
| Not applicable | 12 | 35% |
| Phase 2 | 11 | 32% |
| Phase 1 | 7 | 21% |
| Phase 3 | 4 | 12% |
What the phase mix means for Intellectual Disability
Phase distribution across an umbrella category cannot be interpreted meaningfully. Check the underlying condition of any cited study before treating it as relevant.
The later-phase studies themselves
| 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 |
| NCT00654433 — ALD-101 Adjuvant Therapy of Unrelated Umbilical Cord Blood Transfusion (UCBT) in Patients With Inherited Metabolic Diseases | Phase 3 | Terminated | 40 | Aldagen | 2008-03 |
| 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 |
How to read phase labels
Early phases exist to find harm and set a dose. They are not built to detect benefit, and they routinely produce encouraging-looking numbers that later trials fail to reproduce. Only a confirmatory design with a comparison arm can separate the intervention from everything else happening to a patient.
Median planned enrolment across sampled studies here is 38 participants. Small single-arm studies can flag safety problems; they cannot separate a treatment effect from natural fluctuation, placebo response or regression to the mean.
The largest studies by planned enrolment
Size is a crude proxy for what a study can detect, but it separates a serious attempt from a case series presented as evidence.
| Study | Phase | Status | Planned n | Lead sponsor | Start |
|---|---|---|---|---|---|
| NCT04090268 — Precision Exercise in Children With Malignant Hemopathies | n/a | Unknown | 380 | University of Milano Bicocca | 2017-04-03 |
| NCT04122742 — Diagnosis of RSTS: Identification of the Acetylation Profiles as Epigenetic Markers for Assessing Causality of CREBBP and EP300 Variants. | n/a | Unknown | 154 | University Hospital, Bordeaux | 2019-10-08 |
| NCT02171104 — MT2013-31: Allo HCT for Metabolic Disorders and Severe Osteopetrosis | Phase 2 | Active Not Recruiting | 149 | Masonic Cancer Center, University of Minnesota | 2014-07-10 |
| NCT00176904 — Stem Cell Transplant for Inborn Errors of Metabolism | Phase 2, Phase 3 | Completed | 135 | Masonic Cancer Center, University of Minnesota | 1995-01 |
| NCT01962415 — Reduced Intensity Conditioning for Non-Malignant Disorders Undergoing UCBT, BMT or PBSCT | Phase 2 | Recruiting | 100 | Paul Szabolcs | 2014-02-04 |
Frequently asked
What research stage is stem-cell therapy for Intellectual Disability at?
4 of 27 records are labelled Phase 3 or 4 (2026-08-29).
Is a Phase 3 trial proof that it works?
No — it is a design capable of testing that question. Proof depends on the reported result, replication, and whether the outcome measured matters to patients.
Why do so many records have no phase?
Observational studies and some cell-therapy protocols are registered without a phase label. It is a registry field, not a quality rating.
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.