A sponsor planning a prion disease trial has to find eligible people quickly. The numbers below come from public registry records read on 31 October 2026 and from CDC. They describe the sponsors’ stated designs, not enrolment results.
How many people could be eligible?
The CDC gives the incidence of CJD as about 1 to 2 cases per million people per year in many countries, including the United States, with about 85 percent sporadic. Median survival from symptom onset is about 4 to 5 months, so the time between diagnosis and a trial’s screening window is short. Prion disease can be confirmed only on brain tissue, but probable diagnosis uses clinical criteria and tests such as RT-QuIC, so trials can enrol living people on a probable diagnosis. For example, the Broad Institute study requires a probable diagnosis by CDC criteria plus a positive CSF RT-QuIC or a PRNP genetic test.
Where do the registered trials recruit?
| Trial | Registered sites | Status in the record |
|---|---|---|
| PrProfile (ION717, Ionis) | 13 sites: Boston, New York and Cleveland in the United States; Parkville, Australia; Montreal; Paris; Gottingen; Tel Aviv; Milan; three in Japan; Barcelona | Active, not recruiting; 85 participants enrolled |
| PrP-siRNA study (Broad Institute) | 5 sites in the United States: Massachusetts General Hospital, Mayo Clinic, Columbia University Medical Center, University Hospitals Cleveland, Vanderbilt University Medical Center | Recruiting; 45 planned |
| ALN-6457 (Regeneron) | No sites listed | Not yet recruiting; 60 planned, with an estimated start of 23 October 2026 |
All three require participants aged 18 or more and, in the records read, a caregiver or the ability to complete study procedures. Eligibility is as stated by each sponsor on the dates above, and it changes. The Broad record includes symptomatic adults with no more than moderate impairment and pre-symptomatic adults with a highly penetrant PRNP variant. The ALN-6457 record covers sporadic or genetic prion disease. PrProfile required early-stage disease.
What do registries and surveillance centres provide?
The United States National Prion Disease Pathology Surveillance Center, supported by the CDC, coordinates autopsy and neuropathology for suspected cases and offers diagnostic testing. Its page also lists treatment trials among its programmes. The page read does not give case counts. National surveillance and cohort resources for other countries are described under registries and cohorts and the hospitals and clinics list in the Atlas.
What is not known?
- How many eligible people each site sees per year. None of the records gives this.
- Whether screen failure rates, travel and the lumbar puncture requirement limit enrolment. Participants must be able to travel and have no contraindication to lumbar puncture or MRI, according to all three records, but their effect on recruitment is not reported.
- Whether new sites will open. The registry records list only the sites above.
See unmet need and patient numbers, the regulatory pathway and the pharma overview.
Sources for this page
- CDC: Clinical overview of Creutzfeldt-Jakob disease
- ClinicalTrials.gov NCT06153966: PrProfile, a study of ION717
- ClinicalTrials.gov NCT07444580: PrP-targeting siRNA safety and mechanism study
- ClinicalTrials.gov NCT07832370: a trial of ALN-6457 in symptomatic prion disease
- National Prion Disease Pathology Surveillance Center, Case Western Reserve University