Condition (MeSH)
Rett Syndrome
ClinicalTrials.gov lists 95 trials for Rett Syndrome or a narrower condition beneath it.
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Trials per phase
95 of the 95 trials are tagged with Rett Syndrome itself; the rest are tagged with a narrower condition beneath it.
When did Rett Syndrome trials start? (26)
Shown in this order: most recent first, 1990 onwards. 2026 is partial: trials registered with a 2026 start date so far, not a full year. 1 trial is registered to start in 2027 or later, and not listed here.
Trials over time, by phase
- Phase 1
- Phase 1/2
- Phase 2
- Phase 2/3
- Phase 3
- Not applicable
- Observational
Top of scale: 10
Trials registered with a start date in each year, 1990 onward, stacked by phase (complete years only; the current partial year is in the table's notes). The table below lists the same counts, most recent years first.
| Year | Trials started |
|---|---|
| 2026 (partial year) | 6 |
| 2025 | 5 |
| 2024 | 4 |
| 2023 | 10 |
| 2022 | 4 |
| 2021 | 6 |
| 2020 | 7 |
| 2019 | 6 |
| 2018 | 3 |
| 2017 | 5 |
Showing 10 of 26 earlier years.
Forecast of the full-year count, planned starts included, not rows of this table: about 8 trials starting in 2026 and about 7 in 2027, the average of the 24 months through September, counted as registered and carried forward. The rows of this table count trials registered so far with a start date in the year, planned starts included; the forecast looks ahead to the count for the whole year, so it is not the same measure. In backtests on conditions of this size, forecasts made part-way through the year were typically off by about 28 percent and ran about 20 percent low against the count later registered; forecasts made before the year began were off by about 39 percent and ran about 37 percent low against the count later registered. These figures rest on a few years of history (target years from 2018 to 2025, varying by figure), place each condition as it is mapped today rather than as it was then, and score against a count for the newest year that was still being revised. Only condition series were scored.
Prediction, not a registry value: median of 36 months from start to primary completion across 10 trials still running at the 2026-10-09 snapshot; registered median of 25 months across 50 trials with a primary completion typed Actual. Source: ClinicalTrials.gov / AACT (CTTI), public domain.
What phase are Rett Syndrome trials in? (7)
Shown in this order: phase order.
Show the trials by phase as a table
| Phase | Trials |
|---|---|
| Phase 1 | 6 |
| Phase 1/2 | 4 |
| Phase 2 | 17 |
| Phase 2/3 | 5 |
| Phase 3 | 13 |
| Not applicable | 20 |
| Observational | 30 |
How many Rett Syndrome trials are recruiting? (8)
Shown in this order: the order a trial moves through, from not yet recruiting to unknown.
| Status | Trials |
|---|---|
| Not yet recruiting | 2 |
| Recruiting | 13 |
| Enrolling by invitation | 2 |
| Active, not recruiting | 10 |
| Completed | 47 |
Showing 5 of 8 statuses.
Status as registered on ClinicalTrials.gov. Each trial is counted once.
Which lead sponsors run the most Rett Syndrome trials? (7)
Shown in this order: most trials first. Lead sponsors the registry classes as industry, NIH, US federal, other government or network. A hospital or university the registry files as government can appear here. Sponsors it classes as academic or other are shown on the full page, because that class cannot separate an institution from a named investigator.
| Sponsor | Trials |
|---|---|
| ACADIA Pharmaceuticals Inc. | 4 |
| Eunice Kennedy Shriver National Institute of Child Health and Human Development (NICHD) | 4 |
| Anavex Life Sciences Corp. | 3 |
| Edison Pharmaceuticals Inc | 3 |
| Taysha Gene Therapies, Inc. | 3 |
Showing 5 of 7 sponsors.
Which drugs are being tested for Rett Syndrome? (4)
Shown in this order: most trials first. One row per drug, matched to a single molecule under all its names, ranked by number of trials.
| Drug | Trials |
|---|---|
| NNZ-2566 | 6 |
| Cannabidiol | 2 |
| ANAVEX2-73 | 2 |
| EPI-743 | 2 |
Interventions as named in the registry (11)
Shown in this order: most trials first.
| Drug | Trials |
|---|---|
| Dextromethorphan syrup | 4 |
| Donepezil HCI (drug) | 2 |
| Copaxone-Teva | 2 |
| NTI164 | 2 |
| Rett-T | 1 |
Showing 5 of 11 interventions.
These are the names sponsors entered on ClinicalTrials.gov that we have not matched to a single molecule. Some are drugs under a brand or code name; others are procedures, doses or arm labels.
Which serious adverse events do Rett Syndrome trials report? (10)
Shown in this order: most subjects affected first. Subjects affected summed across trials, a cross-trial signal, not a rate.
| Adverse event | Subjects affected | Trials |
|---|---|---|
| Seizure | 17 | 6 |
| Pneumonia | 12 | 4 |
| COVID-19 | 6 | 4 |
| Acute respiratory failure | 4 | 2 |
| Aspiration | 4 | 3 |
Showing 5 of 10 adverse events.
Which publications cover Rett Syndrome? (193)
Shown in this order: major-topic papers first, then newest, then most linked to trials.
| Publication | Journal | Year | Major topic |
|---|---|---|---|
| Preclinical Milestones in MECP2 Gene Transfer for Treating Rett Syndrome. | Developmental neuroscience | 2025 | Yes |
| A randomized, placebo-controlled, cross-over trial of ketamine in Rett syndrome. | Journal of neurodevelopmental disorders | 2025 | Yes |
| Results from the phase 2/3 DAFFODIL study of trofinetide in girls aged 2-4 years with Rett syndrome. | Med (New York, N.Y.) | 2025 | Yes |
| Self-regulating gene therapy ameliorates phenotypes and overcomes gene dosage sensitivity in a mouse model of Rett syndrome. | Science translational medicine | 2025 | Yes |
| Exposure-Response Efficacy Modeling to Support Trofinetide Dosing in Individuals with Rett Syndrome. | Advances in therapy | 2024 | Yes |
Showing 5 of 193 publications.
Prevalence (33)
Shown in this order: jurisdiction, then disease name. Orphanet observation for the mapped ORPHA concept; the mapping relation column says whether that concept is exactly this condition or broader or narrower.
| Orphanet disease | Type | Class | Geography | Jurisdiction | Mapping relation |
|---|---|---|---|---|---|
| Rett syndrome | Point prevalence | 1-9 / 100 000 | United Kingdom | GB | Exact |
| Rett syndrome | Point prevalence | 1-9 / 100 000 | United Kingdom | GB | Unspecified |
| Rett syndrome | Point prevalence | 1-9 / 100 000 | United Kingdom | GB | Exact |
| Rett syndrome | Prevalence at birth | 1-9 / 100 000 | United States | US | Exact |
| Rett syndrome | Prevalence at birth | 1-9 / 100 000 | United States | US | Unspecified |
Showing 5 of 33 prevalence observations.
Rare-disease identity (2)
Shown in this order: exact, broader, narrower, other.
| Orphanet disease | ORPHA code | Relation | Source |
|---|---|---|---|
| Rett syndrome | 778 | Exact | Orphadata Science knowledge files, Product 1 |
| Rett syndrome | 778 | Exact | Orphanet Rare Disease Ontology (ORDO) |
Not on this page
Not measured: delivery record.
Checked, with nothing recorded for this condition: sub-conditions in mesh.