Key Findings From the TRAILBLAZER-ALZ 2 Study

The TRAILBLAZER-ALZ 2 study (NCT04437511) demonstrated significant clinical benefits of donanemab-azbt in early symptomatic Alzheimer disease (AD). Here are the key findings:

Efficacy Outcomes

  • Cognitive & Functional Decline:

    • 35% slower decline on the Integrated Alzheimer’s Disease Rating Scale (iADRS) vs placebo at 76 weeks in the low/medium tau population[2][6].

    • 39% reduced risk of progressing to the next disease stage (e.g., mild to moderate dementia)[3][6].

    • 47% of participants showed no clinical progression at 1 year (vs 29% on placebo)[3].

  • Amyloid Clearance:

    • 84% reduction in amyloid plaques at 18 months (vs 59% in earlier trials)[6].

    • 85 centiloid reduction in amyloid PET levels by week 76[1].

Tau Pathology Impact

  • Low/Medium Tau Group:

    • Strongest treatment effect (35% iADRS benefit)[2][5].

    • High-tau subgroup showed no significant clinical benefit, reinforcing the importance of early intervention[2][5].

Safety Profile

  • ARIA Incidence:

    • 24% developed ARIA-Edema (ARIA-E), mostly asymptomatic[3][5].

    • 25% experienced microhemorrhages (ARIA-H)[3][6].

    • 3 fatal ARIA cases reported (2 directly attributed, 1 post-serious ARIA)[3].

  • Infusion Reactions:

    • Occurred in 13% of participants (vs 4% placebo), manageable with rate adjustments[2][6].

Study Design Highlights

  • Population: 1,736 participants aged 60–85 with early AD (mild cognitive impairment/mild dementia) and confirmed amyloid/tau pathology[1][4].

  • Dosing Protocol:

    • 700 mg IV monthly × 3 doses → 1400 mg monthly thereafter[1].

    • Blinded dose reduction to placebo if amyloid clearance achieved[1][5].

  • Imaging Requirements:

    • Mandatory MRIs pre-infusions 2–4 and 7[5].

    • Exclusion criteria: >4 microhemorrhages or severe white matter disease[5].

Regulatory & Practical Implications

  • First Phase 3 anti-amyloid trial to demonstrate disease-modifying effects via iADRS[3][6].

  • Supports finite treatment duration (~6–18 months) for patients achieving amyloid clearance[1][5].

  • Eli Lilly submitted for FDA approval in 2023, positioning it as a potential third amyloid-targeting therapy[3][4].

This trial confirms donanemab’s role in slowing early AD progression but underscores the need for tau stratification and vigilant MRI monitoring to mitigate ARIA risks[2][5].


Citations:

[1] https://www.neurology.org/doi/10.1212/WNL.98.18_supplement.1688

[2] https://pmc.ncbi.nlm.nih.gov/articles/PMC10352931/

[3] https://www.endalznow.org/alz-news/almost-half-of-participants-in-anti-amyloid-study-show-no-disease-progression-in-one-year

[4] https://www.alzheimer-europe.org/news/results-lillys-trailblazer-alz2-clinical-trial-donanemab-are-presented-alzheimers-association?language_content_entity=en

[5] https://jamanetwork.com/journals/jama/fullarticle/2807533

[6] https://atrinews.usc.edu/resources/donanemab-significantly-slowed-cognitive-and-functional-decline

[7] https://pubmed.ncbi.nlm.nih.gov/37459141/

[8] https://alz-journals.onlinelibrary.wiley.com/doi/full/10.1002/alz.13700

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