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Parkinson's Disease (PD)Early Phase 1NCT06891703

[18F]ACI-15916 PET in α-synucleinopathies

A Early Phase 1 study testing [18F]ACI-15916 in people with Parkinson's Disease (PD) and Multiple System Atrophy (MSA), run by AC Immune SA at 1 site in Sweden.

Recruiting

Looking for participants now. Contact the study team or a site below to ask about taking part.

Sites and contacts
Official record
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Trial summary

The goal of this clinical trial is to test whether we can reliably and safely measure the accumulation of pathological protein α-synuclein [involved in some diseases such as Parkinson's disease, Lewy body dementia and Multiple System Atrophy (MSA), collectively named α-synucleinopathies] using a new positron emission… Read more about this study

Who is it for?
Ages 20 years and olderHealthy volunteers can take part
What is being tested?
[18F]ACI-15916
Type of treatment
Injection or infusion
Could I receive a placebo?
No, everyone receives an active treatment
How many people
46 participants
Where
1 siteSweden
Study dates
20 Mar 2025to Dec 2026
Phase
Early Phase 1
Are there results?
Not yet: the study is under way

Key requirements

Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.

  • Ages 20 years and older
  • All sexes
  • Healthy volunteers accepted
  • Adult, Older adult

Who may be able to join

  • Subject is able to provide written informed consent, which must be obtained before any assessment is performed.
  • Subjects must be able to understand and be willing to comply with study procedures, restrictions, and requirements.
  • Body mass index is > 18 and < 31 kg/m2 and Bodyweight ≥ 50 kg and ≤ 100 kg.
  • Female participants must not be of childbearing potential or agree to use highly effective methods of contraception.
  • For subjects receiving arterial cannulation, an adequate circulation to the hand for safe placement of arterial line (as determined by Allen's test).
  • Additional Inclusion Criteria for Healthy Volunteers:
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  • Males and females aged ≥ 20 at the time of signing the informed consent.
  • Normal MRI and DAT PET or SPECT (except for Part 4 participants), as judged by the investigator.
  • The subject is, in the opinion of the investigator, generally healthy based on the assessment of medical history, physical examination, vital signs, ECG, and the results of the hematology, clinical chemistry, urinalysis, serology, and other laboratory tests.
  • No family history of α-synucleinopathy, including PD, or other early-onset neurological disease associated with dementia.
  • No personal history of clinically significant neurologic and/or psychiatric disorders.
  • Have a Montreal Cognitive Assessment (MoCA) score ≥ 26
  • No cognitive impairment as judged by the PI or delegated physician.
  • Additional Inclusion Criteria for Participants with α-synucleinopathies:
  • Males and females aged ≥ 40 at the time of signing the informed consent.
  • Subjects diagnosed with any of the following:
  • Idiopathic PD based on MDS criteria
  • PD with genetic risk factor (except some mutations as mentioned in exclusion criteria)
  • Dementia with Lewy bodies (DLB)
  • Diagnosis of possible or probable Multiple System Atrophy (MSA)
  • Evidence of dopamine transporter deficit on DAT PET or SPECT imaging performed either as part of Screening or previously acquired (if not older than 6 months) and of good quality as judged by the investigator.
  • Medications taken for symptomatic treatment of α-synucleinopathy must be maintained on a stable dosage regimen for at least 30 days before the Screening Visit.

Who cannot join

  • Female subjects pregnant, lactating or breastfeeding.
  • Presence of psychiatric symptoms that may interfere with the objectives of the study, as judged by the investigator.
  • Clinically significant concomitant disease or condition within 6 months prior to screening, that could interfere with the conduct of the study, or that would, in the opinion of the investigator, pose an unacceptable risk to the participant, or compromise the scientific quality of the study.
  • History of brain surgery or any neurosurgical procedures. Subject has received treatment with a drug, antibody or vaccine targeting α-synuclein.
  • Known or suspected drug, alcohol or other abuse, or positive urine drug screen which may interfere with the study objective, as judged by the investigator.
  • History of severe allergy/hypersensitivity or ongoing allergy/hypersensitivity as judged by the investigator.
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  • Subject is involved in the planning and/or conduct of the study (i.e. part of the study team)
  • History of clinically significant cardio-or cerebrovascular, pulmonary, renal, hepatic, neurological, mental or gastrointestinal disorder or any other major disorder that may interfere with the objectives of the study, as judged by the investigator.
  • History of and/or screening brain MRI scan (except for Part 4 subjects) indicative of, clinically significant abnormality including but not limited to prior haemorrhage or infarct or >3 lacunar infarcts, except changes consistent with α-synucleinopathies for PD, MSA, DLB patients.
  • Subjects being treated with any anticoagulants or antiplatelet drugs, except aspirin at doses of 100 mg daily or lower within 2 weeks of the planned arterial cannula placement (if performed) for either the baseline or retest imaging.
  • Screening supine blood pressure > 150 mm Hg (systolic) or > 90 mm Hg (diastolic), following at least 5 minutes of supine rest. If blood pressure (BP) is > 150 mm Hg (systolic) or > 90 mm Hg (diastolic), the BP should be repeated two more times and the average of the three BP values should be used to determine the subject's eligibility.
  • Electrocardiographic (ECG) abnormalities of clinical significance as judged by the investigator. Screening supine 12-lead ECG demonstrating QTc > 450 msec at Screening.
  • Any contraindications to obtaining a brain MRI (except for Part 4 subjects), DaT-SPECT (except for Part 4 subjects) or PET (e.g., claustrophobia unresponsive to reassurance or low dose of an anxiolytic agent, metal implants not compatible with MRI or known hypersensitivity to the active substance or to any of the excipients) and ability to tolerate lying in the scanner for up to ~180 minutes.
  • Previous exposure to radiation for medical, scientific or other reasons which could have a high negative impact on the research subject, as judged by the investigator.
  • Treatment with any other investigational therapy within 5 drug elimination half-lives or 30 days (whichever is longer) prior to inclusion in the study.
  • Additional Exclusion Criteria for Healthy Volunteers:
  • Current use of CNS active drugs, including antidepressant or neuroleptic medications is not permitted, anti-inflammatory drugs or sleep medications may be allowed at the discretion of the investigator.
  • History of neurological disease/condition that may interfere with the objectives of the study, as judged by the investigator.
  • Additional Exclusion Criteria for Participants with α-synucleinopathy:
  • Medical history indicating a Parkinsonian syndrome other than idiopathic PD, including but not limited to, progressive supranuclear palsy, drug-induced parkinsonism, essential tremor, vascular parkinsonism, primary dystonia or corticobasal syndrome (CBS).
  • Known carriers of certain familial PD gene mutations (PRKN, PINK1, DJ1, LRRK2), based on previous source documentation.

Trial locations and contacts

1 site in 1 country. Contact the study team or a site near you to ask about taking part.

AC Immune SA Clinical Trial Information contact

+41 21 34 59 121

clinicaltrials@acimmune.com

Sweden1 site, 1 recruiting
  • Karolinska Institutet

    Solna

    Andrea Varrone, (+46) 070-744 27 28, andrea.varrone@ki.se

    Zarah Gander, (+46) 070-266 67 14, zarah.gander@ki.se

    Recruiting

Other trials in Sweden

About this study

Official title: Phase 1 Study to Evaluate [18F]ACI-15916 as a Potential PET Radioligand for Imaging α-synuclein Deposits in the Brain of Patients With Suspected α-synuclein Pathology Compared With Healthy Volunteers

The goal of this clinical trial is to test whether we can reliably and safely measure the accumulation of pathological protein α-synuclein [involved in some diseases such as Parkinson's disease, Lewy body dementia and Multiple System Atrophy (MSA), collectively named α-synucleinopathies] using a new positron emission tomography (PET) tracer called [18F]ACI-15916. Both healthy people and people with (suspected) α-synuclein pathology will participate to this trial.

The main questions it aims to answer are:

Read more
  • whether [18F]ACI-15916 is safe and well tolerated when injected into participants
  • whether [18F]ACI-15916 reliably detects α-synuclein in the brain using PET technique.
  • whether there are differences in the amount of this protein between people with diseases related to α-synuclein accumulation in the brain and people without these diseases.

Participants will:

  • Visit the clinic to consent to their participation and to ensure they are eligible [physical and neurological examinations, questionnaires, blood and urine tests, ECG and in some cases a MRI and a PET scan with a licensed tracer ([18F]FE-PE2I) to confirm or not the disease].
  • Visit the clinic to receive the tracer [18F]ACI-15916 intravenously and be scanned in a PET scanner, during which blood will be collected (and optionally spinal fluid).
  • Receive a phone call from the clinic 1 week after the PET scan to report any symptoms and side-effects that they may be having.

Some of the participants may be asked to come again to the clinic for a second PET scan with [18F]ACI-15916, allowing the researchers to determine if the measurements with the first PET scan are stable and reproducible.

Some of the participants will participate in a specific part of the study to evaluate the distribution of the PET ligand in the whole body, with a similar visit schedule.

Read the detailed description

This is an open-label, first in human (FiH) positron emission tomography (PET) microdose study in patients with suspected α-synuclein pathology and healthy volunteers (HVs) using [18F]ACI-15916 as a novel radioligand. This study will be dedicated to qualification of the ligand [18F]ACI-15916 to measure α-synuclein pathology using PET investigations, including estimation of effective dose and test-retest reliability.

The study consists of four parts in which a total of up to 46 participants may be included:

  • Part 1: Up to 5 HVs and up to 5 patients with Parkinson's Disease (PD) will be included.
  • Part 2: Up to 30 additional subjects including: HV cases (maximum 10) and patients with α-synucleinopathies such as PD, Multiple System Atrophy (MSA) and Dementia with Lewy Bodies (DLB).
  • Part 3: Up to 10 participants from Part 1 and/or Part 2 will have a second PET measurement within one month after their initial PET measurement to evaluate test-retest variability and reproducibility.
  • Part 4. Up to 6 HVs (3 female and 3 male) will undergo a whole-body PET-CT examination to estimate the effective dose after one administration of [18F]ACI-15916.

The four study parts can overlap.

The study consists of a screening period of up to 60 days to assess participants' eligibility, a PET scan with [18F]ACI-15916 along with arterial blood sampling, and a safety phone call following the scanning visit. For participants in Part 3, a second PET scan with [18F]ACI-15916 will be performed up to one month after the first scan to evaluate test-retest variability and reproducibility, followed by a new safety phone call. For subjects in Part 4 (dosimetry), no arterial blood sampling will be performed. The total study duration will be up to 10 weeks for Part 1, 2 and 4 participants and up to 14 weeks for Part 3 participants.

Being tested
[18F]ACI-15916
Medical subject headings
Parkinson Disease, Multiple System Atrophy, Lewy Body Disease

What participants receive

What participants receive. In a randomised study each person is assigned to one group by chance.

  • [18F]ACI-15916Other

    [18F]ACI-15916 is an intravenously administered radioactive imaging agent being studied as a potential positron emitting radiopharmaceutical for in vivo imaging of α-synuclein deposits.

Study groups in NCT06891703
Study groupRoleWhat they receive
Participants with suspected α-synucleinopathiesExperimentalThe study population will be composed of participants with suspected α-synucleinopathies
Receives: Other: [18F]ACI-15916
Healthy volunteersActive comparatorThe study population will be composed of healthy volunteers
Receives: Other: [18F]ACI-15916

What is being measured

The primary outcome is the main question the study is designed to answer.

  1. Number of participants with Adverse Events (AEs) assessed by severity (mild, moderate, severe, life threatening, death) and causal relationship (not related, unlikely related, possibly related or related)

    Measured: From Informed Consent Signature (screening) to safety phone call after PET scan (i.e. up to 14 weeks in total)

  2. Number of participants with clinically significant changes in vital signs measurements

    Vital signs measurements will be performed after the PET scan is completed and will be compared with measurements performed before the injection of [18F]ACI-15916

    Measured: During PET scan visit (i.e. at Day 0): before [18F]ACI-15916 injection and after the PET scan is completed

  3. Brain uptake of the tracer [18F]ACI-15916

    [18F]ACI-15916 uptake in relevant regions of interest of the brain will be measured with PET scan and the mean of each group (participants with α-synucleinopathies and healthy volunteers) will be calculated

    Measured: At the time of the [18F]ACI-15916 PET scan (i.e. at Day 0): 0-93 minutes after injection

Secondary outcomes (3)
  1. Assessment of simplified methods to quantify brain uptake of the tracer [18F]ACI-15916

    Reference tissue models will be used to quantify the brain uptake of the tracer [18F]ACI-15916 using an appropriate reference region in the brain. The mean will be calculated for each group (healthy volunteers and α-synucleinopathies)

    Measured: At the time of the [18F]ACI-15916 PET scan (i.e. at Day 0): 0-93 minutes after injection

  2. Variability of the tracer brain uptake between two [18F]ACI-15916 PET scans (test/retest)

    The repeatability/reliability of the [18F]ACI-15916 brain uptake measures will be assessed by calculating the variability (percentage difference) of the tracer brain uptake between the first and the second [18F]ACI-15916 PET scan for each participant in study Part 3, and the mean will be calculated.

    Measured: From the first PET scan (i.e. Day 0) to the second PET scan (i.e. Day 30)

  3. Radiation dosimetry after one [18F]ACI-15916 PET scan

    The radiation dose absorbed by relevant vital organs and the total effective dose will be measured for each participant of study Part 4, and the mean of scanned participants will be calculated

    Measured: At the time of the [18F]ACI-15916 PET scan (i.e. at Day 0): 0-6 hours after injection

Timeline

From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.

  1. First posted24 Mar 2025
  2. Study start20 Mar 2025
  3. Primary completionDec 2026 (estimated)
  4. Study completionDec 2026 (estimated)

Resources

More details

For doctors and researchers: how the study is designed, who runs it, and its registry IDs.

Study design
Study type
Interventional
Phase
Early Phase 1
Primary purpose
Diagnosis
Allocation
Non-randomised
Intervention model
Parallel groups
Masking
None (open label)
Enrolment
46 participants (estimated)
IDs, dates and publications
ClinicalTrials.gov ID
NCT06891703
Sponsor's protocol ID
ACI-15916-PD-2401
Other IDs
2024-515664-31-00
Status last verified
Oct 2026
First submitted
18 Mar 2025
Last updated
28 Oct 2026
Results posted
No
Data monitoring committee
No
FDA-regulated drug
No
FDA-regulated device
No
Individual data sharing
Undecided

Questions about this trial

What is this clinical trial studying?

A Early Phase 1 study testing [18F]ACI-15916 in people with Parkinson's Disease (PD) and Multiple System Atrophy (MSA), run by AC Immune SA at 1 site in Sweden.

The full registered description is in the About this study section and the official record.

Who may be eligible to take part?

The sponsor lists 22 inclusion and 21 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.

Is this clinical trial currently recruiting?

The record says: looking for participants now, as of the sponsor's last update on 28 Oct 2026. Status can change between updates, so confirm with the study contact before making plans.

Where is the study taking place?

The record lists 1 site in Sweden. Whether a site is taking part right now should be confirmed with that site. See every site.

What are the possible benefits and risks?

They depend on the study and the treatment, and no study can promise a benefit. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.

What does this phase mean?

Early Phase 1 (sometimes called Phase 0) studies give a very small amount of a treatment to a few people, mainly to see how the body handles it.

Not every study follows the same path, and some studies (observational studies, device studies) have no phase.

Are results available for this study?

This study is still under way. Results are not available in the source record yet.

How can a doctor refer a patient or contact the research team?

Contact AC Immune SA Clinical Trial Information (+41 21 34 59 121, clinicaltrials@acimmune.com), or a site near the patient. AzTrials does not enrol participants or take referrals.

What does the primary outcome measure?

Number of participants with Adverse Events (AEs) assessed by severity (mild, moderate, severe, life threatening, death) and causal relationship (not related, unlikely related, possibly related or related) (time frame: From Informed Consent Signature (screening) to safety phone call after PET scan (i.e. up to 14 weeks in total)). The study lists 3 primary outcomes in all. It is what the study was designed to measure, not a finding.

Where can I read the original study information?
Does a listing mean the treatment is approved or proven to work?

No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.

How often is this information updated?

AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 28 Oct 2026.

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