News | May 18, 2012

Dyeing to Paint the Alzheimer’s Brain

May 18, 2012 — Alzheimer’s disease (AD) is a neurodegenerative disease of the brain characterized by beta-amyloid plaques. Most patients are diagnosed late-stage in the disease or are misdiagnosed with another form of dementia. The three hallmark biomarkers for AD are neurofibrillary “tangles,” protein amyloid or “neuritic plaques” and granulovacuolar degeneration of neurons. Unfortunately there is currently no “live” brain imaging diagnostic tool per se, as the imaging that is used occurs only when the progression of the disease is late-stage or postmortem.

Computed tomography (CT) and magnetic resonance imaging (MRI) have been used for years to rule out other causes of dementia. More recently, positron emission tomography (PET) and cerebral metabolism using fluoro-deoxy-D-glucose (FDG) have been used to show characteristic changes in the brain and help rule in Alzheimer’s pathophysiological processes.

In April the U.S. Food and Drug Administration (FDA) approved Avid Radiopharmaceuticals’ (now part of Eli Lilly) Amyvid, a brain plaque diagnostic tool using florbetapir (F-AV-45). This radiotracer agent is delivered intravenously and is drawn to beta-amyloid plaque, a characteristic of AD. This allows a physician to see accumulations of amyloid in the brain, which in turn help the physician to determine whether a patient is suffering from some form of dementia, but cannot confirm a diagnosis of AD. Other diseases such as Parkinson’s disease, Huntington’s disease and Creutzfeldt-Jakob disease characteristically present with plaques as well, therefore physicians must still use mental and behavior cues to diagnose a patient with AD.

Amyvid’s half-life is close to 110 minutes, compared to the previously used radiotracer known as PiB (Pittsburg compound B [fluorescent analog of thioflavin T]), which offered a half-life of only 20 minutes. A longer half-life means more time allowed for the physicians to perform the injection and analysis of a patient. Unfortunately, the downside to using florbetapir is its high cost and patient exposure to radioactive material.

Amyvid is the only FDA-approved diagnostic PET tracer for imaging plaques in vivo, but there looks to be another agent in the pipeline that could potentially provide more diagnostic armament for detecting AD. Navidea Biopharmaceuticals’ AZD4694 Fluorine-18 labeled dye has completed Phase IIa clinical trials, and Phase III clinical trials will likely begin in 2013. This entity has been shown to be highly sensitive in detecting amyloid plaque. The signal-to-noise ratio remains low due to low background and white matter uptake, thus providing clear images of amyloid plaques. Navidea hopes AZD4694 will be used as an early identification tool for AD.

The next step for brain imaging will have to be an imaging agent that can lead to an AD diagnosis, but for now Amyvid will be a great complement for tracking disease progression. GlobalData is confident that with Amyvid on the market, more novel agents will follow to become primary diagnostic tools for the diagnosis of AD.

For more information: www.globaldata.com

Related Content

Siemens Healthineers Announces FDA Clearance of syngo.via VB30 Molecular Imaging Software
Technology | Nuclear Imaging | July 16, 2018
At the 2018 Annual Meeting of the Society of Nuclear Medicine and Molecular Imaging (SNMMI), June 23-26 in Philadelphia...
SNMMI Image of the Year Highlights Theranostic Approach for Advanced Prostate Cancer

IMAGE OF THE YEAR: PSMA PET before and after lutetium-177 PSMA617 theranostics in 8 patients with metastatic prostate cancer who exhausted standard therapeutic options.

68Ga-PSMA11 PET maximum intensity projection (MIP) images at baseline and 3 months after 177Lu-PSMA617 in 8 patients with PSA decline ≥ 98 percent in a prospective phase II study. Any disease with SUV over 3 is in red. Credit: Michael Hofman, John Violet, Shahneen Sandhu, Justin Ferdinandus, Amir Iravani, Grace Kong, Aravind Ravi Kumar, Tim Akhurst, Sue Ping Thang, Price Jackson, Mark Scalzo, Scott Williams and Rodney Hicks, Peter MacCallum Cancer Centre, Melbourne, Australia.

News | PET Imaging | June 29, 2018
In the battle against metastatic castrate-resistant prostate cancer, studies have demonstrated a high response rate to...
MILabs Introduces Futuristic PET Capabilities on New VECTor6 System
Technology | PET Imaging | June 28, 2018
At the 2018 Society of Nuclear Medicine and Molecular Imaging (SNMMI) annual meeting, June 23-26, in Philadelphia,...
Philips North America and GE Healthcare Win IMV PET Imaging ServiceTrak Awards
News | PET Imaging | June 25, 2018
IMV, part of the Science and Medicine Group and a market research and business intelligence provider to the imaging...
FDA Clears New Imaging Functionalities for Biograph mCT PET/CT Systems
Technology | PET-CT | June 21, 2018
Siemens Healthineers will announce U.S. Food and Drug Administration (FDA) clearance of four new system features for...
PET/CT Changes Care for 59 Percent of Suspected Recurrent Prostate Cancer Cases
News | Prostate Cancer | June 13, 2018
A recently presented investigational clinical trial evaluated the impact of 18F fluciclovine positron emission...
News | Computed Tomography (CT) | May 21, 2018
The Istituto Oncologico Veneto (IOV) in Padua, Italy, has acquired MILabs’ latest-generation Versatile Emission...
PET Imaging Agent Could Provide Early Diagnosis of Rheumatoid Arthritis

Coronal 18F-FEDAC PET/CT section of a mouse with collagen-induced arthritis. (A) On day 23 and day 37, increased uptake is noted in the front and hind paws of this mouse with collagen-induced arthritis. (B) Predictive performance of day 23 18F-FEDAC uptake for the development of clinical arthritis. ROC = receiver operating characteristic; Sn = sensitivity; Sp = specificity. Credit: Seoul National University and Ewha Womans University, Seoul, South Korea

News | PET Imaging | May 17, 2018
A novel positron emission tomography (PET) tracer developed by Korean researchers can visualize joint inflammation and...
PET Imaging Shows Protein Clumping May Contribute to Heart Failure Development
News | PET Imaging | May 11, 2018
A team led by Johns Hopkins University Researchers has discovered that protein clumps appear to accumulate in the...
News | Radiopharmaceuticals and Tracers | May 09, 2018
Blue Earth Diagnostics signed an exclusive, worldwide agreement with Scintomics GmbH, Germany, a specialist in...
Overlay Init