Condition (MeSH)
Rare Diseases
ClinicalTrials.gov lists 589 trials for Rare Diseases or a narrower condition beneath it. National Center for Research Resources (NCRR) has the most among industry and government lead sponsors, with 164.
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Trials per phase (log scale)
1 more section with rows
589 of the 589 trials are tagged with Rare Diseases itself; the rest are tagged with a narrower condition beneath it.
When did Rare Diseases trials start? (34)
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
- Phase 4
- Not applicable
- Observational
Top of scale: 60
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) | 22 |
| 2025 | 32 |
| 2024 | 27 |
| 2023 | 24 |
| 2022 | 14 |
| 2021 | 28 |
| 2020 | 12 |
| 2019 | 17 |
| 2018 | 15 |
| 2017 | 7 |
Showing 10 of 34 earlier years.
Forecast of the full-year count, planned starts included, not rows of this table: about 28 trials starting in 2026 and about 29 in 2027, the average of the 24 months through September, counted as registered and carried forward, with about 0.7 times the starts already registered for the rest of 2026 added. 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 15 percent and ran about 1 percent high against the count later registered; forecasts made before the year began were off by about 26 percent and ran about 20 percent low against the count later registered. The part-way figures are from forecasts that used a multiple fitted only on earlier years. 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 22 trials still running at the 2026-10-09 snapshot; registered median of 36 months across 137 trials with a primary completion typed Actual. Source: ClinicalTrials.gov / AACT (CTTI), public domain.
What phase are Rare Diseases trials in? (9)
Shown in this order: phase order.
Show the trials by phase as a table
| Phase | Trials |
|---|---|
| Phase 1 | 35 |
| Phase 1/2 | 20 |
| Phase 2 | 91 |
| Phase 2/3 | 6 |
| Phase 3 | 63 |
| Phase 4 | 6 |
| Not applicable | 144 |
| Observational | 220 |
| Expanded access | 4 |
How many Rare Diseases trials are recruiting? (12)
Shown in this order: the order a trial moves through, from not yet recruiting to unknown.
| Status | Trials |
|---|---|
| Not yet recruiting | 16 |
| Recruiting | 86 |
| Enrolling by invitation | 12 |
| Active, not recruiting | 10 |
| Available | 1 |
Showing 5 of 12 statuses.
Status as registered on ClinicalTrials.gov. Each trial is counted once.
Which lead sponsors run the most Rare Diseases trials? (9)
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 |
|---|---|
| National Center for Research Resources (NCRR) | 164 |
| FDA Office of Orphan Products Development | 20 |
| Eunice Kennedy Shriver National Institute of Child Health and Human Development (NICHD) | 13 |
| National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK) | 13 |
| National Institute of Neurological Disorders and Stroke (NINDS) | 13 |
Showing 5 of 9 sponsors.
Which drugs are being tested for Rare Diseases? (6)
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 |
|---|---|
| Cytoxan | 17 |
| METHYLPREDNISOLONE | 9 |
| Prednisone | 8 |
| tin mesoporphyrin | 6 |
| Ursodeoxycholic Acid | 5 |
Showing 5 of 6 drugs.
Interventions as named in the registry (9)
Shown in this order: most trials first.
| Drug | Trials |
|---|---|
| Filgrastime (G-CSF) | 12 |
| Thymoglobulin [Anti-Thymocyte Globulin (Rabbit)] | 10 |
| Globulin, Immune | 7 |
| Lupron / Leuprolide acetate | 7 |
| Cyclosporine 0.05% | 7 |
Showing 5 of 9 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 Rare Diseases 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 |
|---|---|---|
| Pulmonary hypertension NOS | 21 | 1 |
| Hypoxia | 18 | 2 |
| Gastroenteritis | 16 | 5 |
| Dehydration | 13 | 3 |
| Hypotension NOS | 13 | 1 |
Showing 5 of 10 adverse events.
Which publications cover Rare Diseases? (251)
Shown in this order: major-topic papers first, then newest, then most linked to trials.
Showing 5 of 251 publications.
Not on this page
Not measured: delivery record.
Checked, with nothing recorded for this condition: prevalence, rare-disease identity, and sub-conditions in mesh.