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Amyloid brain imaging changed clinical management in 60% of MCI and dementia patients

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Amyloid imaging – should society pay?

Current clinical practice does not routinely include biomarkers, and if given a choice, most patients would prefer brain imaging to spinal fluid-based testing, so IDEAS may be making imaging-based biomarker characterization a real possibility in the future.

Dr. Richard J. Caselli, professor of neurology at the Mayo Clinic in Scottsdale, Ariz., and associate director and clinical core director of Mayo’s Alzheimer’s Disease Center.

Dr. Richard J. Caselli

Ultimately, society will need to decide whether the cost of the test is worth facilitating current treatment options. In the future, however, should an amyloid-based therapy demonstrate clinical efficacy, the test could become essential.

Richard J. Caselli, MD, is professor of neurology at the Mayo Clinic Arizona in Scottsdale and associate director and clinical core director of the Arizona Alzheimer’s Disease Center. He made these comments in an interview.



Amyloid brain imaging with a PET tracer changed clinical management for 60% of patients with a diagnosis of mild cognitive impairment (MCI) and 63% of those with dementia, according to the IDEAS (Imaging Dementia–Evidence for Amyloid Scanning) study published in JAMA .

Dr. Gil Rabinovici of the University of California, San Francisco Michele G. Sullivan/MDedge News

Dr. Gil Rabinovici

Diagnoses changed from Alzheimer’s disease to non–Alzheimer’s disease in 25% of 11,409 patients and from non–Alzheimer’s disease to Alzheimer’s disease in 10.5%, reported Gil Rabinovici, MD, and his colleagues. The use of Alzheimer’s disease drugs doubled in amyloid-positive MCI patients, and increased by a third in amyloid-positive dementia patients. Physicians involved in the study said the scans provided key clinical information in 82% of cases with post-scan management changes.

Scans also benefited amyloid-negative patients. Before the scan, 71% of these carried an Alzheimer’s disease diagnosis; afterward, just 10% did, opening the way for an accurate diagnosis and more effective treatment.

The study was powered to detect a 30% or greater change in the MCI and dementia groups. The 60% change emphasize how useful amyloid PET scans could be in clinical practice, Dr. Rabinovici, the study’s lead author and principal investigator, said in a press statement.

“We are impressed by the magnitude of these results, which make it clear that amyloid PET imaging can have a major impact on how we diagnose and care for patients with Alzheimer’s disease and other forms of cognitive decline,” said Dr. Rabinovici of the University of California, San Francisco.

Alzheimer’s Association leaders were similarly pleased.

“These results present highly credible, large-scale evidence that amyloid PET imaging can be a powerful tool to improve the accuracy of Alzheimer’s diagnosis and lead to better medical management, especially in difficult-to-diagnose cases,” said Maria C. Carrillo, PhD, chief science officer of the Alzheimer’s Association and a coauthor of the study. “It is important that amyloid PET imaging be more broadly accessible to those who need it.”

Dr. Maria C. Carrillo, Alzheimer’s Association chief science officer Michele G. Sullivan/MDedge News

Dr. Maria C. Carrillo

Next steps

Ultimately, investigators hope the nationwide-wide, open-label study will prove the clinical value of amyloid PET scanning and convince the Centers for Medicare & Medicaid Services to make the test a fully covered service for those who meet the appropriate use criteria set forth by the Alzheimer’s Association and the Society of Nuclear Medicine and Molecular Imaging.

IDEAS’ second goal – showing that the scans improve health outcomes – is scheduled for 2020. These data are a key component of the CMS decision, but they might be a tough sell, Clifford R. Jack Jr., MD, and Ronald C. Petersen, MD, PhD, wrote in an accompanying editorial. Dr. Jack and Dr. Petersen are affiliated with the Mayo Clinic in Rochester, Minn.

“For CMS to cover the cost of amyloid PET, it must be demonstrated that the result of a scan has an effect on patient outcomes, not just patient care processes – and, without a disease-modifying therapy available, that might be a challenge,” they wrote.

IDEAS is a funding collaboration of the CMS, the Alzheimer’s Association, Avid Radiopharmaceuticals/Eli Lilly, General Electric Healthcare, Piramal Imaging, and the American College of Radiology. Dr. Rabinovici had no financial disclosures.

SOURCE: Rabinovici GD et al. JAMA. 2019 Apr 2. doi: 10.1001/jama.2019.2000.

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