FDA Approves Second Drug Designed to Help Evaluate for Alzheimer's, Dementia

The Food and Drug Administration approved the second drug to help evaluate patients for Alzheimer's disease and dementia.

Called Vizamyl, the radioactive diagnostic drug works by attaching to the abnormal protein called beta amyloid, found in patients with Alzheimer's. A negative Vizamyl scan, therefore, suggests a person's cause of dementia is not Alzheimer's related, though beta amyloid is sometimes present in the brain of patients with other dementias and in elderly people without neurologic disease. For this reason, a positive scan does not establish a firm diagnosis of Alzheimer's or dementia.

Researchers proved Vizamyl's effectiveness via two clinical studies consisting of nearly 400 patients with a range of cognitive function. All were injected with the drug and then scanned, with the resulting images given to five independent readers. The results clearly demonstrated Vizamyl's ability to correctly detect beta amyloid in the brain.

"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 Dr. Shaw Chen, 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's safety was demonstrated in more than 750 participants. It does not, however, replace other diagnostic tests when evaluating for Alzheimer's and dementia, FDA officials noted. Furthermore, the agency stated that Vizamyl PET images should only be interpreted by health care professionals who have completed training in an image interpretation program.

Safety risks associated with the drug are hypersensitivity reactions, radiation exposure and misinterpretation of results. Side effects include flushing, headache, increased blood pressure, nausea and dizziness.