Intellectual Disability and Haematopoietic stem-cell transplantation (HSCT): what the trial registry contains
The ClinicalTrials.gov registry holds 17 records for HSCT in Intellectual Disability: 2 recruiting now, 2 labelled Phase 3 or 4, across 11 countries. Snapshot 2026-08-29.
Why this is studied in Intellectual Disability
Intellectual disability is an umbrella covering many distinct genetic and acquired causes, which is why aggregate registry counts here are close to meaningless without knowing the underlying diagnosis. Cell approaches address none of the genetic causes directly; the rationale, where stated, is neuroinflammatory or trophic support.
What HSCT means in this table
Haematopoietic transplantation is the oldest and most consequential cell therapy in medicine, with conditioning regimens that carry real mortality risk alongside genuine disease-modifying power. Registrations under this label therefore mix decades-old standard-of-care protocols with newer autoimmune-reset trials, and the risk profile is nothing like that of an outpatient infusion.
The numbers
Every figure below comes from one reproducible query (intellectual disability x hematopoietic stem cell transplantation) run against ClinicalTrials.gov API v2 on 2026-08-29.
| Metric | Value |
|---|---|
| Registered studies (all statuses) | 17 |
| Interventional studies in the sample | 12 |
| Recruiting right now | 2 |
| Completed | 7 |
| Terminated, withdrawn or suspended | 3 |
| Phase 3 or Phase 4 records | 2 |
| Countries with at least one site | 11 |
| Median planned enrolment | 46 participants |
| Largest single planned enrolment | 380 participants |
| First / most recent start year | 1995 — 2020 |
How mature is this evidence?
Only 2 of 17 registrations reached a confirmatory phase label, so most of what a clinic can cite is exploratory work by design.
Completion status: 7 completed, 3 stopped early (18% of all records). A registration is a plan, not a result.
| Phase label | Records | Share |
|---|---|---|
| Phase 2 | 8 | 38% |
| Not applicable | 7 | 33% |
| Phase 1 | 4 | 19% |
| Phase 3 | 2 | 10% |
Median planned enrolment is 46 participants (largest single study: 380). Trials of this size can describe safety and generate hypotheses; detecting a modest clinical benefit reliably usually needs substantially larger numbers with a control group.
Where the studies are
Research is not evenly spread: United States carries about 50% of the country mentions among 11 countries with sites.
| Country | Studies with a site there |
|---|---|
| United States | 15 |
| Italy | 3 |
| Argentina | 2 |
| Germany | 2 |
| Netherlands | 2 |
| United Kingdom | 2 |
| Canada | 1 |
| Australia | 1 |
| Brazil | 1 |
| France | 1 |
Legal pathway differs by country — see where cell therapy is legal, by country.
Who runs them
Among the top lead sponsors, 7 are universities or hospitals and 5 are companies, making this a academic area.
- Masonic Cancer Center, University of Minnesota — 5 records
- Genetix Biotherapeutics Inc. — 2 records
- Paul Szabolcs — 2 records
- University of Florida — 1 record
- University of Milano Bicocca — 1 record
- Talaris Therapeutics Inc. — 1 record
Representative registered studies
Recruiting studies first, then the most advanced phases. Each identifier links to the registry record, where eligibility criteria, outcome measures and contacts are published.
| Study | Phase | Status | Planned n | Lead sponsor | Start |
|---|---|---|---|---|---|
| NCT01962415 — Reduced Intensity Conditioning for Non-Malignant Disorders Undergoing UCBT, BMT or PBSCT | Phase 2 | Recruiting | 100 | Paul Szabolcs | 2014-02-04 |
| NCT04528355 — Data Collection Study of Patients With Non-Malignant Disorders Undergoing UCBT, BMT or PBSCT With RIC | n/a | Recruiting | 50 | Paul Szabolcs | 2020-08-20 |
| 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 |
| NCT02698579 — Long-term Follow-up of Participants With Cerebral Adrenoleukodystrophy Who Were Treated With Lenti-D Drug Product | n/a | Active Not Recruiting | 64 | Genetix Biotherapeutics Inc. | 2016-01-22 |
| 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 |
| NCT00176904 — Stem Cell Transplant for Inborn Errors of Metabolism | Phase 2, Phase 3 | Completed | 135 | Masonic Cancer Center, University of Minnesota | 1995-01 |
| NCT03513328 — Conditioning Regimen for Allogeneic Hematopoietic Stem-Cell Transplantation | Phase 1, Phase 2 | Completed | 6 | University of Florida | 2018-06-15 |
| NCT02559830 — Autologous Hematopoietic Stem Cell Gene Therapy for Metachromatic Leukodystrophy and Adrenoleukodystrophy | Phase 1, Phase 2 | Unknown | 50 | Shenzhen Second People's Hospital | 2015-01 |
| NCT01372228 — Phase I/II Pilot Study of Mixed Chimerism to Treat Inherited Metabolic Disorders | Phase 1, Phase 2 | Terminated | 3 | Talaris Therapeutics Inc. | 2011-04 |
| NCT01043640 — Allogeneic Bone Marrow Transplant for Inherited Metabolic Disorders | Phase 2 | Completed | 46 | Masonic Cancer Center, University of Minnesota | 2009-12 |
What this page does and does not tell you
These figures describe effort, not outcome. Published results, with their control arms and endpoints, are where benefit is decided.
If a clinic offers you this today, the useful question is not "is there research?" but "which of these registered studies is mine part of, and if none, what evidence applies to the exact product I am being sold?" The Provider Question Builder turns that into a scored checklist.
Frequently asked
How many HSCT studies for Intellectual Disability are recruiting right now?
2 of 17 registered records were listed as recruiting in the 2026-08-29 snapshot. Recruitment status changes frequently; the registry record is authoritative.
Is HSCT an approved treatment for Intellectual Disability?
Registration on ClinicalTrials.gov is not approval. Approval is granted by a regulator for a specific product and indication after review of submitted evidence. 17 registered studies tell you research exists, not that a product cleared review.
How advanced is the research on HSCT for Intellectual Disability?
2 of 17 records carry a Phase 3 or Phase 4 label and 7 are marked completed. Registrations run from 1995 to 2020.
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.
Download the query data
Query totals are full API matches; status, phase and country counts describe the first up to 400 returned records per query. Query classes overlap and must not be summed as unique trials. Counts are not treatment outcomes. Snapshot: 2026-08-29. Methods and field definitions.