The challenge of delivery
Intravenous infusions are new to Alzheimer’s disease and pose all sorts of logistical hurdles. The Alzheimer’s Association’s Dr. Carrillo described the situation as “manageable,” noting that infusions are standard of care for many diseases, and that neurologists now have more than 15 years’ experience with them for multiple sclerosis.
Still, most clinicians treating Alzheimer’s disease in the community – neurologists, geriatricians, psychiatrists, and primary care physicians – do not have infusion centers in their practices. Virtually none have experience with or access to PET-amyloid, or with screening for amyloid-related imaging abnormalities–edema (ARIA-e) on MRI, as required by the FDA.
“I contacted the hospital infusion center we use and said I could end up sending five or six patients a week, can you handle this? They only have so many chairs,” Dr. Delio said. “I am one neurologist in a local community, and I might have 50 candidates for this drug. That’s a lot for them.” Patients with cognitive impairment are also difficult to infuse and may need to be treated at home, he noted.
“MRIs are easy enough to do,” Dr. Delio said. “But do we know what ARIA-e looks like on imaging? You’d have to talk to the radiologists – this is another element of uncertainty. Do we even know what we’re looking for with these scans? Will we recognize this?”
Neurologist Jeffrey L. Cummings, MD, ScD, of the University of Nevada, Las Vegas, a vocal proponent of aducanumab and lead author of a May 2021 paper defending the evidence for it, acknowledged that the field was unprepared for a wide-scale adoption of infusions in dementia treatment, pointing to a Rand Corporation study from 2017 that warned that screening, diagnosis, and availability of infusion chairs would have to be drastically scaled up to meet demand.
Dr. Jeffrey L. Cummings
“There are few clinicians who know how to identify MCI, too few imaging centers, too few radiologists who know how to identify ARIA-e on MRI, so all of these things will be required to be put into place. The label doesn’t specify any of this, but good clinical practice will require that, and getting this up and running will take 18 to 24 months,” Dr. Cummings said.
Neurologist David S. Knopman, MD, of the Mayo Clinic in Rochester, Minn., a leading critic of the evidence for aducanumab who recently resigned his position on the independent committee that advises the FDA on neurology drugs, said that for large research institutions like his that have served as trial sites, the transition to offering PET-amyloid, MRI, and infusions in clinical practice will be easier.
Dr. David S. Knopman
“We have all this because this is what we do every day. And we have a very extensive understanding of MCI and mild dementia staging,” Dr. Knopman said. “But the amount of infrastructure that is implied by this, and all the extra steps it would take, would be a real challenge for people in general neurology practice.”
In addition to routine use of PET-amyloid and MRI screening for ARIA-e, Dr. Knopman said, clinicians will have to provide genetic screening and counseling before administering aducanumab, as clinical trials showed that treated patients have a higher risk of developing ARIA-e if they have APOE4, a risk variant for Alzheimer’s disease. “And that has real implications for the families and the children of patients,” he said.