In what could be a big breakthrough, Eli Lilly & Co. has won approval from federal regulators for an imaging test that detects the brain plaque that’s a hallmark of Alzheimer’s disease.
The drug maker received the go-ahead from the U.S. Food and Drug Administration (FDA) late last Friday, and issued a press release on the news Monday.
Lilly and its subsidiary, Avid Radiopharmaceuticals Inc., won federal approval for Amyvid (the brand name for florbetapir), a radioactive diagnostic agent — a dye — that clings to beta-amyloid plaques, a toxic protein found in the brains of patients with Alzheimer’s. These tagged plaques become visible to doctors via a positron emission tomography, or PET, scan.
The development of Amyvid is considered important because it may help doctors diagnose Alzheimer’s in its early stages, when patients are just starting to have memory issues. That may help make it easier for researchers to find a drug that will stop the disease before it has progressed too far.
A negative Amyvid scan would indicates there are sparse or no amyloid plaques present in a patient’s brain, which would rule out Alzheimer’s as a cause of a patient’s cognitive impairment, according to Lilly.
A positive Amyvid scan would mean that moderate to frequent amyloid plaques are present in a patient’s brain. That would mean that the patient could have Alzheimer’s. But these plaques are may also be present in patients with other types of neurologic conditions and in older people with normal cognition.
“It’s important to note that Amyvid is an adjunct to other diagnostic evaluations,” Lilly said in its press release. “A positive Amyvid scan does not establish a diagnosis of Alzheimer’s Disease, or other cognitive disorder. Additionally, the safety and effectiveness of Amyvid have not been established for predicting development of dementia or other neurologic condition, or monitoring responses to therapies.”
Alzheimer’s disease is one of several possible causes of cognitive decline, and Alzheimer’s and other “causes of cognitive impairment share many overlapping symptoms including memory, visuospatial ability, executive function, behavior and language deficiencies,” according to Lilly’s press release.
“It’s estimated that one in five patients clinically diagnosed with probable Alzheimer’s Disease during life do not end up having Alzheimer’s Disease pathology upon autopsy,” said Dr. Daniel Skovronsky, president and CEO of Avid and global brand development leader for Amyvidy. “The approval of Amyvid offers physicians a tool that, in conjunction with other diagnostic evaluations, can provide information to help physicians evaluate their patients.”
Amyvid was evaluated in three clinical studies that examined images from healthy adult patients as well as patients with a range of cognitive disorders, including some terminally ill patients who had agreed to participate in a postmortem brain donation program.
“Florbetapir gives patients with cognitive decline, their families and the physicians who treat them, more information about the amyloid plaques that may be found in their brain,” said Dr. R. Edward Coleman, professor of radiology at Duke University Medical Center. “This approval marks a great advancement in nuclear medicine practice, as it enables us to evaluate the presence or absence of moderate to frequent levels of amyloid plaques in a patient’s brain. In conjunction with other tests, florbetapir may help give physicians additional information when evaluating patients for the cause of their cognitive decline.”
Because Amyvid loses over half of its radioactivity every two hours, Amyvid must be distributed directly from a radiopharmacy to the imaging centers where it will be administered within several hours. Beginning in June, a limited number of radiopharmacies will be distributing Amyvid with the goal of making the product available in more areas as soon as possible.
“The approval of Amyvid exemplifies Lilly’s commitment to discovering and developing innovative products for many of the world’s unmet medical needs,” Lilly USA president Alex Azar said. “We are working hard with our manufacturing partners to increase production of Amyvid and will notify the community as it becomes available in more markets.”
Amyvid is a radioactive diagnostic agent tagged with a radioisotope called fluorine-18. Once Amyvid is injected into a vein, it travels through the bloodstream and into the brain, binding to amyloid plaques. Amyvid produces a positron signal, which is detected by a PET scanner and used to create a brain image.
A radiologist, who should have successfully completed Amyvid reader training, then interprets the image to evaluate for the presence or absence of significant amyloid plaques (i.e., moderate to frequent levels of neuritic plaques) in the brain. This information is reported back to the referring physician, who then determines the next steps in the evaluation and management of the patient.