August 16, 2026

@michaelokun

What excites me about the new FDA approval of tau PET is that it gives us another window into what is actually happening inside the living brain. The FDA-approved tau tracer Tauvid (flortaucipir F18) will allow healthcare specialists to estimate the amount and distribution of aggregated tau tangles in adults with cognitive impairment being evaluated for Alzheimer’s disease. The first Tau PET tracer, Flortaucipir, was actually FDA approved in 2020. We have already seen how transformative amyloid PET can be. FDA-approved amyloid PET tracers can show whether significant amyloid plaque is present, and confirmation of amyloid pathology has become particularly important when determining eligibility for amyloid-lowering treatments such as lecanemab and donanemab. But amyloid is only part of the Alzheimer story. Tau may tell us something different and potentially more personal: where someone is in the disease process and how aggressively the disease may behave. Tau burden and its spread through the brain may correlate more closely with cognitive impairment and progression than amyloid alone. More Tau seems to have worse prognosis w/ some infusion therapies. Thus, a person with substantial tau burden may have a different prognosis and potentially a different expected response to existing amyloid-lowering therapies than someone who is amyloid-positive but has relatively little tau. Importantly, tau PET is not yet a crystal ball or a stand-alone test that tells an individual exactly what will happen, and it is not currently approved as a general screening test for healthy people. But I think we can see where the field may be headed. We now have amyloid PET, tau PET, increasingly powerful blood biomarkers such as phosphorylated tau, and FDA-cleared blood testing that can help identify Alzheimer-associated amyloid pathology. Imagine putting these pieces together rather than treating every person with AD, or every person at risk, as if they were biologically identical. One day we may be able to say: this is how much amyloid you have, this is how much tau you have and where it is, this is what your blood biomarkers show. Here is the path.