Radiotracer Florbetaben allows PET visualization of different beta-amyloid plaque forms in the brain

Recent research [1] shows that PET imaging using the radiotracer Florbetaben (Neuraceq, Piramal Imaging) is able to detect a different form of beta-amyloid plaque that develops early in the brain. This way, the technology might enable the detection of Alzheimer’s disease in its early stages.

Neuraceq, which was approved by the FDA in 2014 for use with PET to assess neuritic beta-amyloid plaque in adult patients with cognitive impairment being evaluated for Alzheimer’s disease and other causes of cognitive decline, was initially not indicated for other types of deposits, such as diffuse and vascular beta-amyloid plaques. However, such types of plaque deposits may also be related to the disease. Former studies indicate that diffuse beta-amyloid plaques are found in the early stages of Alzheimer’s disease, with neuritic ones being more often detected in later stages.

Based on the above observations, the researchers examined the application of Florbetaben also for those types of deposit, using brain tissue samples from end-of-life patients with Alzheimer’s disease, other types of dementia or with no signs thereof. The sample donors (mean age 80.4 years) had undergone Florbetaben-PET scans before death. The results from PET scans in vivo and post-mortem were compared and correlated. Neuritic, diffuse, and vascular beta-amyloid plaques in the frontal, occipital, anterior cingulate and posterior cingulate cortices of the brain were examined. Cortical standardized uptake value ratios (SUVRs) were obtained in all regions of interest, with cerebellar gray matter being used as reference region.

Significant Florbetaben uptake in the frontal and posterior cingulate cortices was found in the PET scans, with high frequency of deposits of both diffuse and neuritic beta amyloid. Differently, only diffuse beta-amyloid plaques contributed significantly to Florbetaben uptake in the occipital and anterior cingulate cortices, while vascular beta amyloid contributed significantly to Florbetaben uptake only in the occipital region.

In addition to application in the staging of Alzheimer’s disease, the results could also lead to an expansion of Florbetaben’s indications. As stated by the Chief Medical Officer at Piramal, Andrew Stephens, only about 80% of patients diagnosed with Alzheimer’s disease have amyloid plaque. Thus, “the clinical diagnosis is not a perfect tool and the advantage of adding biomarkers can help improve diagnostic accuracy”. Stephens adds that it is very important “that these earlier forms of plaques can be detected […] and may provide a more sensitive biomarker for the therapeutic trials looking at earlier stages of plaque”.

BV Cyclotron VU (Amsterdam, the Netherlands) is also a producer of Neuraceq®.

References:
[1] Piramal Imaging. Impact of Morphologically Distinct Beta-amyloid Deposits on 18F-Florbetaben (FBB) PET Scans. SNMMI Annual Meeting (Scientific Session Presentation).