Brain Imaging Agent Approved to Help Assess Patients for Alzheimer ’s Disease, Dementia

A new radioactive diagnostic agent designed for use with positron emission tomography (PET) imaging of the brain in adults currently being evaluated for Alzheimer’s disease (AD) and dementia has been approved for use in the United States.

Dementia is associated with failing brain functions such as judgment, memory, language, and complex motor skills. The dementia caused by AD is tied to the accumulation in the brain of an abnormal protein called beta amyloid and damage or death of brain cells. However, beta amyloid can also be found in the brain of patients with other dementias and in elderly individuals without neurologic disorders.

The US Food and Drug Administration (FDA; Silver Springs, MD, USA) has approved Vizamyl (flutemetamol F18 injection), which works by binding to beta amyloid and producing a PET image of the brain that is used to assess the presence of beta amyloid. A negative Vizamyl scan demonstrates that there is little or no beta amyloid buildup in the brain and the cause of the dementia is probably not due to AD. A positive scan means that there is most likely a moderate or greater amount of amyloid in the brain, but it does not determine a diagnosis of AD or other dementia. Vizamyl does not replace other diagnostic tests used in the evaluation of AD and dementia.

“Many Americans are evaluated every year to determine the cause of diminishing neurologic functions, such as memory and judgment, that raise the possibility of Alzheimer’s disease,” said Shaw Chen, MD, deputy director of the Office of Drug Evaluation IV in the FDA’s Center for Drug Evaluation and Research. “Imaging drugs like Vizamyl provide physicians with important tools to help evaluate patients for AD and dementia.”

Vizamyl is the second diagnostic drug available for visualizing beta amyloid on a PET scan of the brain. In 2012, FDA approved Amyvid (Florbetapir F18 injection) to help evaluate adults for AD and other causes of cognitive decline. Vizamyl’s effectiveness was established in two clinical studies comprised of 384 participants with a range of cognitive function. All participants were injected with Vizamyl and were scanned. The images were interpreted by five independent readers masked to all clinical information. A portion of scan results were also validated by autopsy.

The study’s findings validated that Vizamyl accurately detects beta amyloid in the brain. The results also corroborate that the scans are reproducible and trained readers can accurately interpret the scans. Vizamyl’s safety was established in a total of 761 participants.

Vizamyl is manufactured for GE Healthcare (Chalfont St. Giles, UK) by Medi-Physics, Inc. (Arlington Heights, IL, USA).

Related Links:
GE Healthcare
Medi-Physics
US Food and Drug Administration