Eli Lilly's Alzheimer's Drug Donanemab Shows Potential to Delay Disease Progression: Seeks FDA Approval

Researchers reveal Eli Lilly's experimental Alzheimer's drug, donanemab, can potentially slow the disease progression by about four to seven months. Results from a 1,700-patient study published in the Journal of the American Medical Association indicate the treatment could be the second proven to effectively delay Alzheimer's after the recent approval of Leqembi.

In May, Lilly announced that donanemab appeared to be effective. However, on Monday, the Journal of the American Medical Association published the full results of a study involving 1,700 patients, also presented at the Alzheimer's conference.

Both donanemab and Leqembi are lab-made antibodies, administered intravenously, that target sticky amyloid buildup in the brain—a key factor in Alzheimer's. However, both drugs present a serious safety concern: brain swelling or bleeding. In Lilly's study, this adverse reaction was linked to three deaths.

Approximately 25% of donanemab recipients experienced swelling, and about 20% had microbleeds. An additional concern is that over 90% of the study participants were white, so there is little data on how other populations might respond to the treatment, as noted by Alzheimer's specialist Jennifer Manly of Columbia University.

Lilly's study included individuals aged 60 to 85 in the early stages of Alzheimer's. Half of the participants received once-a-month infusions of donanemab, while the other half received placebo infusions for 18 months.

Participants were switched to a placebo if enough amyloid was cleared out, which occurred in about half of the participants within a year. Additionally, levels of abnormal tau, another culprit in the brain, were tracked since amyloid alone does not cause Alzheimer's. Higher tau levels indicate more advanced disease.

The results showed that both groups declined during the 18-month study. However, those given donanemab experienced a slower decline of about 22%. Some patients fared even better—those with low to medium tau levels experienced a 35% slower decline, suggesting that the drug is more effective in the early stages of the disease. This means that donanemab could potentially delay the worsening of patients by approximately four to seven months, according to a report published in JAMA.

Another way to measure the effectiveness of donanemab is that, among recipients with lower tau levels, 47% remained stable after one year of the study, compared to only 29% of those who received the placebo version.

It is already known that patients receiving any amyloid-targeted therapy require repeated brain scans to monitor for potential side effects, which is costly and time-consuming. This research provides promising insights into the potential benefits of donanemab for Alzheimer's patients, but further studies are needed to understand its efficacy and safety profile better.

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