Donanemab (Kisunla) Authorized in Europe for Early Symptomatic Alzheimer Disease

The European Commission (EC) has granted marketing authorization to Eli Lilly’s donanemab (Kisunla) for treatment of adults with early symptomatic Alzheimer disease (AD), including mild cognitive impairment and mild dementia, who have confirmed amyloid pathology and are apolipoprotein E (ApoE4) heterozygotes or noncarriers.¹

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In Europe, where AD currently affects up to 6.9 million adults, the prevalence is expected to nearly double by 2050.^2,3 Among individuals with mild cognitive impairment, approximately one-third will progress to the next clinical state of the disease within a year.³

“Kisunla demonstrated meaningful results in people with early symptomatic Alzheimer’s disease by significantly slowing cognitive and functional decline in our phase 3 TRAILBLAZER-ALZ 2 study,” Patrik Jonsson, executive vice president and president of Lilly International, said in a statement.¹ “The data show that the earlier patients are identified, diagnosed, and treated with [donanemab], the greater the response to treatment. This authorization brings a new option to patients in Europe—offering hope and the potential for more time to focus on what matters most.”¹

The EC based its authorization on data from the phase 3 TRAILBLAZER-ALZ 2 and phase 3b TRAILBLAZER-ALZ 6 studies. In TRAILBLAZER-ALZ 2, which enrolled 1,736 participants across 8 countries, donanemab significantly slowed cognitive and functional decline over 18 months compared with placebo. The treatment also reduced the risk of progressing to the next clinical stage of disease during the same period, according to Lilly.¹

Dosing Schedule Revised

The approved dosing schedule for donanemab reflects data from Lilly's TRAILBLAZER-ALZ 6 trial, which supported a July 2025 revision to the drug's label approved by the US FDA.⁴ The trial, which enrolled 843 participants ages 60–85 years, demonstrated that a gradual titration regimen over the first 3 doses of donanemab significantly reduced the risk of amyloid-related imaging abnormalities with edema or effusion (ARIA-E) by 41% at 24 weeks (14% vs 24%) and by 35% at 52 weeks (16% vs 25%) compared with the original regimen, without compromising efficacy.⁴ Reductions in amyloid plaque among participants on the revised schedule were comparable to the original results (67% vs 69% at 24 weeks) as were reductions in plasma P-tau217 levels. Lilly reported no new safety signals during the study.⁴

Administered once-monthly via IV infusion, donanemab targets amyloid plaques and is the only AD therapy with evidence that supports treatment discontinuation once amyloid is reduced to minimal levels. The feature is attractive given the potential for reduced infusion burden and treatment costs, according to Lilly.

ARIA remain a key safety concern. These abnormalities, which can include edema or hemorrhage, are often asymptomatic but can cause serious or fatal complications. Patients carrying 1 or 2 copies of the ApoE4 gene face increased risk of both AD and ARIA.

Cognitive Benefit Over 3 Years

New 3-year data from the long-term extension (LTE) of the phase 3 TRAILBLAZER-ALZ 2 trial showed that treatment with donanemab continued to provide cognitive and functional benefit in individuals with early symptomatic AD. The late-breaking findings were presented during the 2025 Alzheimer’s Association International Conference, in July.⁵

Over the 3-year extension, donanemab-treated demonstrated a –1.2 point difference in CDR–Sum of Boxes scores at 36 months vs an untreated cohort. Early treatment reduced the risk of progression to the next stage of Alzheimer’s disease by 27%. More than 75% achieved PET-confirmed amyloid clearance within 76 weeks, and amyloid reaccumulation after therapy cessation was modest (2.4 Centiloids/year). Safety remained consistent, with ARIA-E occurring in fewer than 5% of participants and no new adverse signals observed.⁵

Lilly continues to evaluate donanemab in additional trials, including TRAILBLAZER-ALZ 3, which is assessing use in preclinical disease, and TRAILBLAZER-ALZ 5, an ongoing registration trial in Asia. Kisunla is already marketed in the United States, Japan, China, the United Kingdom, and multiple other regions.