OREANDA-NEWS. July 22, 2015.  Vizamyl PET amyloid imaging provided added value over the standardized workup in assessing patients with suspected early-onset dementia, according to a new study led by Philip Scheltens, Professor of Cognitive Neurology and Director of the Alzheimer Center at the VU University Medical Center in Amsterdam. Professor Scheltens’ team presented data this week, at the Alzheimer’s Association International Conference (AAIC), from a study in which the use of Vizamyl ([18F]flutemetamol) PET imaging improved the confidence of clinical diagnoses and altered the care management plan for more than a third of patients suspected of early-onset dementia.

Vizamyl was approved by the FDA for positron-emission tomography (PET) imaging of the brain to estimate ?-amyloid neuritic plaque density in adult patients with cognitive impairment who are being evaluated for Alzheimer’s disease (AD) and other causes of cognitive decline. A negative scan indicates sparse to no neuritic plaques, inconsistent with a diagnosis of AD at the time of image acquisition and reduces the likelihood that a patient’s cognitive impairment is due to AD. A positive scan indicates moderate to frequent amyloid neuritic plaques, but does not establish a diagnosis of AD or other cognitive disorder. The safety and effectiveness of Vizamyl have not been established for predicting the development of dementia or other neurologic conditions or for monitoring responses to therapies.

Conducted by the VU University Medical Center, Amsterdam, and the University of Maastricht in the Netherlands, the study used Vizamyl PET imaging to analyze 211 patients who presented with early-onset dementia symptoms. There was diagnostic discordance between pre-scan clinical diagnoses and PET imaging results in approximately 25% of cases; in 19% of the cases, the patient’s pre-scan diagnosis changed after Vizamyl imaging. Overall, diagnostic confidence increased from 69±12% to 88±15% after interpretation of the PET images (P<0.001). In 79 (37%) patients, the results led to a change in patient management plans.
 

“This study has generated evidence that adding a Vizamyl scan to the clinical workup of patients with early-onset dementia may influence diagnostic confidence leading to treatment decisions,“ said Ben Newton, director of neurology at GE Healthcare. “Studies such as this one have started to bridge the gap between PET tracer regulatory approval and generation of data to demonstrate the potential value that Vizamyl can bring to the clinical assessment of patients with dementia.“

Members of Professor Scheltens’ team are discussing the study findings during AAIC: Dr. Marissa Zwan presented them at the Alzheimer’s Imaging Consortium, and Dr. Femke Bouwman will again share the data at the GE Healthcare evening symposium “From Research to Routine: The Value of Imaging Biomarkers” on Wednesday, July 22.

About the study

The study included 211 mild, early-onset patients with possible dementia who visited a tertiary memory clinic. After a routine diagnostic workup, patients underwent [18F]flutemetamol PET scans, which were interpreted as amyloid negative or positive based on visual rating. Before and after disclosing PET results, the diagnostic confidence (visual analogue scale 0-100%) and clinical diagnosis were recorded. The study evaluated the impact of [18F]flutemetamol PET on patient management plan. Results showed:

  • [18F]flutemetamol scans were positive in 133 (63%) out of 211 patients, of which 111 out of 145 (77%) patients had a pre-PET AD diagnosis, and 22 out of 66 (33%) patients had a non-AD diagnosis
  • After disclosure of PET image interpretation, 41/211 diagnoses (19%) were changed
  • Overall, diagnostic confidence increased from 69±12% to 88±15% after disclosing PET results (P<0.001)
  • In 79 (37%) patients, [18F]flutemetamol PET results led to a change in patient management. A positive PET scan resulted more often in the initiation of AD medication (n=49 vs n=2 for negative scan; P<0.001). In patients with a pre-scan AD diagnosis and negative amyloid imaging, ancillary investigations were often requested after PET results had been disclosed (n=13 vs n=0 for AD patients with positive PET; P<0.001)

The conclusion from these data was that Vizamyl PET imaging demonstrated added value to a standardized workup in patients with uncertain clinical diagnosis suspected of early-onset dementia. Vizamyl imaging impacted clinical diagnosis, increased overall diagnostic confidence, and altered patient management plans in more than a third of the patients studied.