PROGRESS IN DEVELOPING A LIGHT‐STABLE 4R TAU PET IMAGING AGENT: APN‐1701 FIH

The need for a light stable 4R tau PET tracer for use in diverse tauopathies is widely appreciated. We aimed to assess the initial human imaging profile of [18F]APN‐1701 as such a tracer and to compare its imaging profile to the well‐established but light‐sensitive tracer [18F]‐APN‐1607 that can detect 4R aggregates as well as 3R and mixed 3R/4R aggregates. [18F]APN‐1607 has progressed to a multicenter Phase 2 clinical trial for Alzheimer’s disease (AD); therefore, prior imaging data with it was considered valuable for comparison.