Two PET tracers to image 4R tau in PSP

First-in-Human Study for the Safety and Evaluation of Two 4R Tau Ligands ([18F]ABBV964i and [ 18F]ABBV-965i) as Potential PET Radioligands for Imaging Tau Protein in the Brain of Patients With Probable PSP and Healthy Volunteers

Early Phase 1 Interventional Invicro · NCT07348276

This first-in-human test will see if two PET imaging drugs, [18F]ABBV-964i and [18F]ABBV-965i, can safely show tau protein in the brains of people with progressive supranuclear palsy and healthy adults.

Quick facts

PhaseEarly Phase 1
Study typeInterventional
Enrollment24 (estimated)
Ages18 Years to 80 Years
SexAll
SponsorInvicro Academic / other
Drugs / interventionsradiation
Locations1 site (New Haven, Connecticut)
Trial IDNCT07348276 on ClinicalTrials.gov

What this trial studies

This Phase 1, first-in-human program uses three parts to characterize two 4R tau PET radioligands: dosimetry in healthy volunteers, proof-of-concept brain imaging in PSP and healthy participants, and an optional test-retest assessment. Participants receive intravenous injections of each tracer followed by dynamic PET scans (whole-body for dosimetry, brain for kinetics) and MRI co-registration. Arterial and/or venous blood sampling, radiometabolite analysis, and kinetic modeling (compartmental and graphical methods) are used to derive quantitative metrics such as SUV, SUVR, VT, and DVR. Urine collection and standard dosimetry software are used to estimate organ and whole-body radiation exposure.

Who should consider this trial

Good fit: Ideal candidates are adults with a clinical diagnosis of PSP aged 40–80 or healthy volunteers aged 18–80 who meet weight and safety criteria and can tolerate PET and MRI procedures.

Not a fit: People who are pregnant, have unstable medical conditions, cannot tolerate prolonged imaging or arterial access, or who expect therapeutic benefit from participation are unlikely to receive direct clinical benefit from this imaging-only study.

Why it matters

Potential benefit: If successful, these tracers could provide a clearer way to detect and track tau buildup in PSP, improving diagnosis and the ability to follow disease progression or treatment effects.

How similar studies have performed: Other tau PET tracers have been used in Alzheimer's and some PSP research, but selective 4R tau ligands are relatively novel and this represents a first-in-human evaluation.

Eligibility criteria

Show full inclusion / exclusion criteria
Inclusion Criteria:

* Males or females: PSP 40-80 years; HV 18-80 years
* Body weight: 43-120 kg (95-265 lb)
* Women of childbearing potential: abstinent or use 2 contraception methods (one barrier) during study and 30 days post last injection
* Men: use 2 contraception methods and refrain from sperm donation during study and 90 days post last injection
* Adequate circulation and normal clotting for arterial cannulation
* Sufficient mobility and ability to lie still for imaging
* Healthy Volunteers: informed consent, no clinically relevant findings, no cognitive impairment
* PSP Participants: informed consent or assent with LAR consent, clinical diagnosis per NINDS-SPSP criteria, MRI consistent with PSP, able to ambulate, tolerate MRI, comply with study procedures, caregiver available if needed

Exclusion Criteria:

* History of drug or alcohol abuse in past 12 months
* Clinically significant lab abnormalities or unstable illness
* Investigational drug/device use within 30 days
* Pregnant, lactating, or breastfeeding
* Significant comorbid conditions (GI, CV, hepatic, renal, etc.)
* Abnormal clotting parameters (if arterial sampling)
* MRI contraindications (implants, claustrophobia) for PSP participants
* Use of OTC meds or supplements within 2 weeks (healthy volunteers)
* Use of anti-hemostasis meds within 2 weeks of arterial line placement for PSP participants
* Unable to lie still for 90 minutes
* Major surgery or significant blood loss within 4 weeks
* Positive for Hepatitis B, Hepatitis C, or HIV
* Deemed unsuitable by Investigator

Where this trial is running

New Haven, Connecticut

Study contacts

How to participate

  1. Review the eligibility criteria above with your treating physician.
  2. Visit the official trial page on ClinicalTrials.gov for the most current contact information and recruitment status.
  3. Contact the listed study coordinator or principal investigator to request pre-screening. Pre-screening is free and never obligates you to enroll.
Conditions Progressive Supranuclear PalsyHealthy ParticipantsTauopathyTauPET ImagingABBV-965iABBV-964iPSP
Last reviewed 2026-06-13 by the Find a Trial editorial team. Information on this page is for educational purposes and is not medical advice. Always consult qualified healthcare professionals about clinical trial participation.