Spotlight On | Alzheimers Disease
With the aging population, the proliferation of neurodegenerative diseases, particularly Alzheimer’s, is becoming a truly global burden. In fact, in mid-April, the World Health Organization and Alzheimer’s Disease International released a report calling for governments and policymakers to make dementia a global public health priority. Thus, molecular imaging research and industry is scrambling to meet the needs of this burgeoning population.
Amyvid is a radioactive diagnostic agent tagged with a radioisotope called fluorine-18. Amyvid binds to amyloid plaques, a characteristic of AD, and is detected using PET/CT scan images of the brain.
A negative Amyvid scan indicates sparse to no amyloid plaques are currently present, which is inconsistent with a neuropathological diagnosis of AD and reduces the likelihood that a patient’s cognitive impairment is due to Alzheimer’s. Conversely, a positive Amyvid scan indicates moderate to frequent amyloid plaques are present; this amount of amyloid plaque is present in patients with Alzheimer’s disease, but also may be present in patients with other types of neurologic conditions and in older people with normal cognition.
AD is a progressive neurodegenerative disease characterized by, among other things, deposits of extracellular B-amyloid (A?) plaques and intraneuronal neurofibrillary tangles with accompanying decreases in cerebrospinal fluid (CSF) A? and increases in CSF tau proteins, the study authors wrote.
In the Phase II study, the researchers enrolled 27 patients; eight were treated with bapineuzumab and 19 with placebo. They evaluated whether bapineuzumab affected the CSF levels of the downstream biomarkers, total tau (T-tau) and phosphorylated tau (P-tau), as well as the primary biomarker A? in the completed trials.
Although there was a reduction in CSF T-tau, Blennow and colleagues noted that it did not reach statistical significance compared with placebo. The study results indicated no clear-cut differences were observed for CSF A?. However, they noted that the observed decrease in both P-tau and T-tau require further examination.
DIAN is a network of 11 research centers established in 2008 by funding from the National Institute on Aging to investigate Alzheimer’s disease caused by rare, dominantly inherited genetic mutations. Children of individuals who carry one of these genetic mutations have a 50-50 chance of inheriting the gene mutation, and those who do are destined to develop the disease. Mutation carriers have a young-onset version of Alzheimer’s disease; symptoms typically begin in their 30s, 40s or 50s.
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| 1: Negative amyloid PET study in an elderly patient with cognitive impairment indicates sparse to no neuritic plaques and is inconsistent with a neuropathological diagnosis of Alzheimer’s disease. 2: Amyloid PET/CT study in a patient with cognitive impairment being evaluated for Alzheimer’s disease and other causes of cognitive decline shows a high level of tracer binding to amyloid plaques in the brain. Images obtained with Siemens Biograph mCT and evaluated with 510(k)-pending syngo.PET Amyloid Plaque software. Source: University of Tennessee, Knoxville, TN |
U.S. FDA approves Amyvid for Alzheimer’s assessment
The FDA has approved Amyvid, a radioactive diagnostic agent (Eli Lilly and Avid Radiopharmaceuticals) that is indicated for brain imaging of beta-amyloid plaques in patients with cognitive impairment who are being evaluated for Alzheimer’s disease (AD) and other causes of cognitive decline.Amyvid is a radioactive diagnostic agent tagged with a radioisotope called fluorine-18. Amyvid binds to amyloid plaques, a characteristic of AD, and is detected using PET/CT scan images of the brain.
A negative Amyvid scan indicates sparse to no amyloid plaques are currently present, which is inconsistent with a neuropathological diagnosis of AD and reduces the likelihood that a patient’s cognitive impairment is due to Alzheimer’s. Conversely, a positive Amyvid scan indicates moderate to frequent amyloid plaques are present; this amount of amyloid plaque is present in patients with Alzheimer’s disease, but also may be present in patients with other types of neurologic conditions and in older people with normal cognition.
No clear efficacy answer about cerebrospinal fluid biomarkers in Alzheimer’s
Immunotherapy with the antibody bapineuzumab in patients with mild to moderate AD resulted in decreases in a cerebrospinal fluid biomarker, which may indicate downstream effects on the degenerative process, according to research published April 2 in the Archives of Neurology.AD is a progressive neurodegenerative disease characterized by, among other things, deposits of extracellular B-amyloid (A?) plaques and intraneuronal neurofibrillary tangles with accompanying decreases in cerebrospinal fluid (CSF) A? and increases in CSF tau proteins, the study authors wrote.
In the Phase II study, the researchers enrolled 27 patients; eight were treated with bapineuzumab and 19 with placebo. They evaluated whether bapineuzumab affected the CSF levels of the downstream biomarkers, total tau (T-tau) and phosphorylated tau (P-tau), as well as the primary biomarker A? in the completed trials.
Although there was a reduction in CSF T-tau, Blennow and colleagues noted that it did not reach statistical significance compared with placebo. The study results indicated no clear-cut differences were observed for CSF A?. However, they noted that the observed decrease in both P-tau and T-tau require further examination.
Alzheimer’s Association awards $4.2M to study young-onset disease
The Alzheimer’s Association has awarded its largest research grant—nearly $4.2 million over four years—to the Dominantly Inherited Alzheimer’s Network-Therapeutic Trials Unit (DIAN-TTU), based at Washington University School of Medicine in St. Louis, to enable the program to move forward with drug and biomarker trials in people with genetically based, young-onset Alzheimer’s disease.DIAN is a network of 11 research centers established in 2008 by funding from the National Institute on Aging to investigate Alzheimer’s disease caused by rare, dominantly inherited genetic mutations. Children of individuals who carry one of these genetic mutations have a 50-50 chance of inheriting the gene mutation, and those who do are destined to develop the disease. Mutation carriers have a young-onset version of Alzheimer’s disease; symptoms typically begin in their 30s, 40s or 50s.