NCT06891703

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

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

• Status: Recruiting
• Phase: EARLY_Phase 1
• Study type: Interventional
• Enrollment: 46 (estimated)
• Sponsor: AC Immune SA · Industry
• Sex: All
• Age: 20 Years
• Healthy volunteers: Accepted

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 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: * 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.

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.

Conditions

• Parkinson's Disease (PD)
• Multiple System Atrophy (MSA)
• Dementia With Lewy Bodies (DLB)

Interventions

Type	Name	Description
OTHER	[18F]ACI-15916	\[18F\]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.

Timeline

• Start date: 2025-03-20
• Primary completion: 2026-03-01
• Completion: 2026-03-01
• First posted: 2025-03-24
• Last updated: 2025-11-19

Locations

1 site across 1 country: Sweden