FDA Formalizes Amyloid PET Scans as Gatekeeper for Antiamyloid Alzheimer's Drugs

A peer reviewed account by FDA staff describes 2025 label changes that let three approved brain scans be used specifically to select patients for amyloid clearing therapies, and that allow a numerical plaque reading alongside the standard visual read.

The Food and Drug Administration has formally documented, in a peer reviewed journal, its own 2025 decision to add a new indication to the labels of three approved amyloid beta PET imaging drugs: selecting patients for amyloid beta directed Alzheimer's therapies. The account, published online February 19, 2026 in the Journal of Nuclear Medicine and written by scientists in the FDA's Division of Imaging and Radiation Medicine, states that lecanemab-irmb and donanemab-azbt, the two amyloid clearing drugs marketed for mild cognitive impairment or mild Alzheimer's dementia, require confirmation of amyloid pathology before treatment starts, and that the three approved PET tracers, florbetapir, flutemetamol and florbetaben, are one option for that confirmation.

Florbetapir (Amyvid) was first approved in 2012 to estimate amyloid plaque density in patients being evaluated for Alzheimer's disease. Eli Lilly announced on June 25, 2025 that the FDA had approved a label update adding the therapy selection indication and allowing quantitative measurement of plaque levels, using scales such as Centiloid or standardized uptake value ratio, alongside the existing visual read. Life Molecular Imaging announced a similar expansion for florbetaben (Neuraceq) on July 1, 2025. The FDA authors note that the quantitative labeling change was informed by the use of Centiloid thresholds in Eli Lilly's TRAILBLAZER-ALZ and TRAILBLAZER-ALZ 2 donanemab trials, where those thresholds were used to enroll patients with elevated amyloid and to decide when to stop dosing.

The labeling action is regulatory bookkeeping, not new clinical trial data. It documents which biomarker test the FDA now formally recognizes as an eligibility check for two already marketed drugs; it does not report on how well those drugs work, and the JNM authors do not present new efficacy findings. A positive or elevated scan tells a clinician that amyloid plaque is present at a level consistent with Alzheimer's pathology, information used to confirm eligibility for treatment; it does not by itself diagnose Alzheimer's dementia, predict how an individual patient will respond to amyloid clearing therapy, or rule out other causes of cognitive decline.

Families weighing amyloid PET as part of a treatment discussion should ask their clinician what a given result does and does not mean for their own diagnosis and options, since the label change concerns eligibility testing, not treatment outcomes.