A Phase 1/2 interventional study of ALN-6457 in Prion Disease, sponsored by Regeneron Pharmaceuticals. Not yet recruiting. Open to participants aged 18 Years and older. Per ClinicalTrials.gov, last updated 2026-09-22.
Sponsored by Regeneron Pharmaceuticals · Phase 1/2, Interventional, and Treatment
This study will test a Regeneron drug called ALN-6457 ("study drug") to see if it can help treat Prion Disease (PrD).
In PrD, the prion protein folds into an abnormal shape. These abnormal proteins build up in the brain and cause damage to brain cells, leading to problems with thinking, memory, and movement.
ALN-6457 is designed to reduce the amount of prion protein made in the brain. ALN-6457 works by targeting the genetic "instructions" that cells use to produce this protein, with the goal of slowing or stopping disease progression.
This study is looking at:
2,372 studies on the registry are indexed under Dementia; 574 are open to participants now.
This study's planned enrollment of 60 is below the median of 90 across 1,758 interventional studies indexed under Dementia.
Browse Dementia studies →Regeneron Pharmaceuticals is the lead sponsor of 411 studies on the registry; 90 are open to participants now.
Of its 125 completed or terminated interventional studies of FDA-regulated products, 79 (63%) have results posted.
Counted across the registry records on this site, refreshed daily.
Key Inclusion Criteria:
Participant must meet all of the criteria under either:
Key Exclusion Criteria:
NOTE: Other Protocol-Defined Inclusion/Exclusion Criteria Apply.
Underlined terms in the criteria open these too. Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Weight in kilograms divided by height in metres squared. Example: 70 kg and 1.75 m gives 70 ÷ (1.75 × 1.75) ≈ 22.9.
What counts as overweight or obesity differs between countries (some use lower cut-offs), so go by the range the study states.
Judged by the study doctor to matter for your health or for the study. It is a doctor’s decision, so ask the study team if you are unsure whether something counts.
A reason a treatment, test or procedure should not be given to a particular person, such as an allergy, another illness or a medicine they take.
Malignancy means cancer. Criteria about another or earlier malignancy ask whether you have had a different cancer, usually within a set number of years.
Some are commonly allowed, such as treated skin cancers other than melanoma and early cancers removed completely — check the exceptions this study lists.
BMI (body mass index)
Weight in kilograms divided by height in metres squared. Example: 70 kg and 1.75 m gives 70 ÷ (1.75 × 1.75) ≈ 22.9.
What counts as overweight or obesity differs between countries (some use lower cut-offs), so go by the range the study states.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Clinically significant
Judged by the study doctor to matter for your health or for the study. It is a doctor’s decision, so ask the study team if you are unsure whether something counts.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Contraindication
A reason a treatment, test or procedure should not be given to a particular person, such as an allergy, another illness or a medicine they take.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Cancer (malignancy)
Malignancy means cancer. Criteria about another or earlier malignancy ask whether you have had a different cancer, usually within a set number of years.
Some are commonly allowed, such as treated skin cancers other than melanoma and early cancers removed completely — check the exceptions this study lists.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Drug: ALN-6457
Drug: ALN-6457
Administered per the protocol
Also known as: ALN-PRNP
Occurrence of Treatment Emergent Adverse Events (TEAEs)
Time frame: Through Week 156
Severity of TEAEs
Time frame: Through Week 156
Percentage change in concentration of Neurofilament Light chain (NfL) in plasma from baseline
Time frame: Through Week 130
Concentration of Prion Protein (PrP) in CSF
Time frame: Through Week 130
Change from baseline in concentration of PrP in CSF
Time frame: Through Week 130
Concentration of ALN-6457 and its major metabolites in plasma
Time frame: Through Week 130
Concentration of ALN-6457 and its major metabolites in CSF
Time frame: Through Week 130
Overall survival rate
Time frame: At Week 52
No study locations are listed for this record.
Plan to share: Yes — All Individual Patient Data (IPD) that underlie publicly available results will be considered for sharing.
Supporting information: Study protocol, Statistical analysis plan, Informed consent form, Clinical study report, Analytic code
Time frame: When Regeneron has: received marketing authorization from major health authorities (e.g., FDA, European Medicines Agency (EMA), Pharmaceuticals and Medical Devices Agency (PMDA), etc.) for the product and indication or has globally discontinued development of the product for all indications on or after April 2020 and has no plans for future development made the study results publicly available (e.g., scientific publication, scientific conference, clinical trial registry) the legal authority to share the data, and ensured the ability to protect participant privacy
Access criteria: Qualified researchers can submit a proposal for access to individual patient or aggregate level data from a Regeneron-sponsored clinical trial through Vivli. Regeneron's Independent Research Request Evaluation Criteria can be found at: https://www.regeneron.com/sites/default/files/Regeneron-External-Data-Sharing-Policy-and-Independent-Research-Request-Evaluation-Criteria.pdf
Data sharing details ↗ · vivli.org
No publications or documents are linked to this record.
Start is estimated for Oct 2026; primary completion for Feb 2031, 52 months later.
Of 17 phase 1/2 interventional studies under Dementia, half reached primary completion within 49 months of starting (the median), counting those still running; a quarter within 24 and three quarters within 68. This study's planned 52 months is close to that.
How these figures are worked out, and which studies are left out of them.
This study is not yet recruiting, as verified in Sep 2026. You cannot join it, but the record below documents what was studied.
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