Safety issues
However, the drug is not without some safety concerns. Amyloid-related imaging abnormalities (ARIAs) occurred in 36.8% of the treatment group versus 14.9% of the placebo group, and in 40.6% of patients who were homozygous for apo E4 and received the drug. Microhemorrhage occurred in 26.8% in the donanemab group versus 12.5% in the placebo group.
Most ARIA cases were mild to moderate and resolved or stabilized with appropriate management. However, three deaths were determined to be drug related among participants who developed serious ARIAs or brain bleeding and swelling.
An important study limitation was that it enrolled primarily White patients (91.5%), which may limit generalizability to other populations, and the age limit was 85 years, which some believe is an inadequate representation of older adults. In addition, the 18-month treatment window limits the long-term understanding of donanemab’s benefits and side effects.
Eli Lilly has filed a submission to the Food and Drug Administration. If approved, donanemab will be the third antiamyloid monoclonal antibody to receive this status, following aducanumab (Aduhelm) and lecanemab (Leqembi).
Strongest data yet
Commenting on the study findings, Percy Griffin, PhD, director of scientific engagement, Alzheimer’s Association, said these new results are “very, very exciting” and represent “the strongest data to-date” for antiamyloid monoclonal antibodies in Alzheimer’s disease.
“A good percentage of individuals on the drug actually saw a complete clearance of amyloid, and some had to be taken off the drug, because if you’re on an antiamyloid drug and there’s no amyloid, what are you going for?”
He noted that the study had some unique aspects, including using tau-PET “to see whether or not the drug is more effective in subpopulations.”
Access to this and other antiamyloid therapies should be a priority, said Dr. Griffin. “We have to make sure people who have the potential to benefit from these treatments do.”
The Alzheimer’s Association is calling for Medicare beneficiaries who are living with the disease to receive the same coverage afforded to those with other diseases.
“The Centers for Medicare & Medicaid Services policy to block Medicare access to FDA-approved Alzheimer’s disease treatments is in stark contrast to scientific evidence, is unprecedented and must be reversed immediately,” Joanne Pike, DrPH, president and CEO of the Alzheimer’s Association, said in a press release.
Also important is tracking the longitudinal performance of these drugs outside of clinical trials, said Dr. Griffin. “Not everyone is going to be in that Goldilocks zone of being able to see a doctor whenever they want and have access to these PET and MRI tools and other things used in clinical trials.”
He noted that the Alzheimer’s Association is leading a network for diagnostics and therapeutics (ALZ-NET) that will track the performance of novel FDA-approved Alzheimer’s disease therapies “in the real world.”
While these are exciting findings for antiamyloid therapy, “we can’t take our foot off the gas, we need more therapies that target different aspects of the disease biology,” said Dr. Griffin.
A version of this article appeared on Medscape.com.