Donanemab’s three-year data indicate that its benefit in slowing early Alzheimer’s decline increased over time, according to research presented at AAIC 2026 in London.
Eli Lilly presented further analyses from the TRAILBLAZER-ALZ 2 extension study at the conference. The company first disclosed the core three-year findings at AAIC 2025.
Patients who started donanemab earlier recorded a 0.6-point advantage after 18 months on the Clinical Dementia Rating–Sum of Boxes scale. The difference increased to 1.2 points after 36 months compared with a matched untreated external group, Eli Lilly said.
Earlier treatment also reduced the risk of progressing to the next disease stage by 27% compared with delayed treatment. More than 75% of assessed patients achieved amyloid clearance within 76 weeks.
The extension included 550 patients who started donanemab during the original trial and 657 who initially received a placebo. However, the three-year comparison used external data because placebo patients could switch to donanemab after 18 months.
Donanemab does not cure Alzheimer’s or prevent further decline. Instead, the evidence suggests that it can modestly slow deterioration in memory, thinking and daily functioning during the disease’s early stages.
Read: Donanemab: A Major Leap in Alzheimer’s Treatment
Britain’s medicines regulator licensed donanemab, marketed as Kisunla, in October 2024 for eligible adults with early Alzheimer’s. It remains unavailable for routine NHS treatment because NICE found that its benefits did not justify the drug, infusion and monitoring costs.
Read: Brain Immune Cells Discovered That Slow Alzheimer’s Disease
The treatment can also cause amyloid-related imaging abnormalities. These include brain swelling and bleeding, which can become serious, life-threatening or fatal in rare cases.
