Katholieke Universiteit te Leuven
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Leuven, Belgium
Not yet recruitingRare disease
Phase 1/2 Study of ALN-6457 Sodium to Assess Safety and Tolerability in Adults with Symptomatic Prion Disease
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What is this trial about?
A plain-language summary of the goals, design and what participants do
The trial involves adults with symptomatic Prion Disease, a rare brain disorder that causes gradual loss of thinking, movement, and other functions. The investigational drug being tested is ALN-6457 sodium, supplied as a solution for injection that is delivered directly into the spinal fluid surrounding the spinal cord, a method known as intrathecal administration.
The purpose of the study is to assess how safe the medication is, how well participants tolerate it, and whether it reduces levels of a blood marker called Neurofilament Light chain, which signals damage to nerve cells. Participants will receive several doses of the drug over a set period, with regular check‑ins that include blood draws (plasma samples) and a small collection of fluid from the spine (CSF) to measure the drug, the marker, and the amount of Prion Protein present. The trial will also record overall survival and any side effects that arise.
The research process
The trial runs in 8 steps – from screening to follow-up. Each step says what happens and what the team monitors.
Who can join the trial?
7 criteria
- You must have either sporadic Creutzfeldt‑Jakob disease (CJD) – a form that appears randomly without a family history – or genetic Prion Disease, which is inherited, as defined by the study protocol.
- Your Body Mass Index (BMI) must be less than 35 kg/m² at the screening visit. BMI is a number that compares your weight to your height.
- You need to be able to understand the study questions and fill out the required questionnaires during screening.
- You must be within the age range set by the study (the trial includes participants from the age groups identified as codes 3 and 4).
- The study accepts both male and female participants.
- You must be a patient who has the disease being studied (Prion Disease).
- Any other requirements that are written in the study protocol must also be met.
Who cannot join the trial?
8 criteria
- Having a serious heart, lung, liver, kidney, digestive, hormone, blood, mental health, or nervous system condition (other than prion disease) that the doctor thinks could affect the study results or make participation riskier.
- Having a past brain or spinal cord disease or injury that would make a Lumbar Puncture (LP) (a needle test to collect spinal fluid) difficult or would affect the flow of cerebrospinal fluid (CSF).
- Any reason that would make a Magnetic Resonance Imaging (MRI) (a detailed scan of the brain using magnets) unsafe for you.
- Having an allergy or intolerance to local anesthetics (medicines that numb the area for procedures).
- Having a current bleeding disorder (bleeding diatheses) that could cause extra bleeding during the lumbar puncture.
- Having any cancer (malignancy) that is getting worse or needs active treatment.
- Having tried to kill yourself, or having thoughts of suicide with a plan that required hospital admission or a change in care within the past 12 months.
- Any other reasons listed in the study’s detailed rules that would exclude participation.
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Investigated drugs
ALN-6457 sodium is an experimental medicine that is being given directly into the fluid around the spinal cord (intrathecal injection). In this trial it is the drug being tested to see if it is safe and well‑tolerated in people who have symptoms of prion disease. Researchers are also looking at whether the medicine can affect a blood marker that shows nerve cell damage, and whether it might improve the disease symptoms.
What is already known about the treatment
ALN-6457 sodium - It is given as a sterile solution for injection that is delivered directly into the spinal fluid (intrathecal injection). The drug is still experimental and is being studied in early‑phase clinical trials for safety and how it works in people with prion disease. It is designed to lower the production of the normal prion protein by binding to the messenger RNA that makes it, which may help slow the brain damage caused by the disease. ALN‑6457 sodium belongs to the class of antisense oligonucleotides, a type of gene‑silencing medication.
Investigated diseases
Prion disease - A rare neurodegenerative disorder caused by abnormal prion proteins that accumulate in the brain. The buildup leads to loss of nerve cells, resulting in gradually worsening memory loss, confusion, and changes in behavior. Motor abilities such as coordination and walking become increasingly impaired as the disease advances. Over time, patients develop severe neurological decline that affects most bodily functions.
Trial detailsLast updated 31 Oct 2026
Age18+ yearsPhasePhase I/IITrial ID2026-526727-21-00Protocol codeALN-6457-PD-25129Estimated enrolment48 patientsSponsorRegeneron Pharmaceuticals Inc.
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