Lilly's Kisunla Maintenance Strategy Rests on Unproven Link Between Amyloid Levels and Clinical Benefit

Lilly Explores Kisunla Maintenance Dosing Post-Amyloid Clearance

Eli Lilly is exploring the potential for maintenance therapy with its Alzheimer's drug, Kisunla, for patients who have achieved amyloid clearance. This initiative stems from long-term data from the Phase 3 TRAILBLAZER-ALZ 2 study, which showed that patients reaccumulate amyloid at a rate of 2.4 centiloid per year after initial treatment. The company is conducting an addendum study (TRAILBLAZER-ALZ 6) to investigate a 1,400 mg once-a-year maintenance dose to sustain amyloid clearance, addressing physician concerns about plaque return and potentially offering a competitive advantage.

• Long-term extension data from the Phase 3 TRAILBLAZER-ALZ 2 study, which supported Kisunla's approval, revealed that patients reaccumulate amyloid at a rate of 2.4 centiloid per year after treatment completion. This rate is comparable to natural accumulation, and patients maintained low amyloid levels through 154 weeks of follow-up, reinforcing the benefit of earlier intervention.
• Eli Lilly is conducting an addendum study of the TRAILBLAZER-ALZ 6 trial to evaluate a potential maintenance dose of 1,400 mg once a year. This study aims to characterize the ability of such a dose, given at least a year after original treatment, to sustain amyloid clearance and prevent plaque return, with enrollment expected to complete early next year.
• In a separate development, the FDA approved a modified titration regimen for Kisunla in July 2025, following early findings presented in October 2024. This adjusted schedule, starting with 350 mg and gradually increasing to 1,400 mg by week 4, significantly reduced cases of brain swelling compared to the original 700 mg initial dose.

Addressing Amyloid Reaccumulation: The Need for Kisunla Maintenance

Published data from long-term studies and open-label extensions indicate that established Alzheimer's disease (AD) therapies, particularly cholinesterase inhibitors, provide clinically meaningful benefits. Studies have tracked patients on rivastigmine, donepezil, and galantamine for up to five years, demonstrating that while decline is not halted, it may be slowed compared to no treatment. For instance, a 12-month study of galantamine in patients with AD and cerebrovascular disease (CVD) showed that continuous treatment maintained cognitive function, whereas patients who switched from placebo to active treatment at six months improved but did not attain the same cognitive level. However, the durability of this response is not indefinite. A two-year study of rivastigmine noted that after an initial one-year period of stabilization, cognitive and functional measures began to decline, although behavioral and psychotic symptoms, especially delusions, continued to show improvement over the full two years.

The broader landscape of AD treatment confirms a persistent need for durable maintenance strategies. For moderate-to-severe AD, treatments like memantine and donepezil, used alone or in combination, provide measurable benefits, but their optimal duration of use as the disease progresses remains unknown. Evidence also supports the use of complementary non-pharmacological approaches; for example, combining reality orientation (RO) with donepezil for six months led to improved scores on the CERAD neuropsychological battery and Mini-Mental State Examination (MMSE) compared to controls. Looking forward, while newer agents like the anti-amyloid antibody donanemab-azbt are entering the clinical landscape, further research is considered essential to validate their long-term outcomes, assess effectiveness across diverse patient populations, and refine dosing strategies to optimize the benefit-risk profile.

Kisunla vs. Leqembi: Navigating the Alzheimer's Treatment Landscape

The Alzheimer's disease treatment landscape has undergone a fundamental transformation over the past five years, shifting from purely symptomatic management toward disease-modifying intervention. For decades, cholinesterase inhibitors such as donepezil represented the standard of care, offering only modest symptomatic benefit in a minority of patients without altering underlying disease progression. This paradigm began to change with the advent of anti-amyloid β-directed passive immunotherapies, with published trial data now available for aducanumab, lecanemab, and donanemab. Notably, donanemab—targeting pyroglutamyl(3)-Aβ protein—has demonstrated superior plaque clearance and cognitive benefit compared with older cholinesterase inhibitors, while offering the added feature of treatment discontinuation once amyloid clearance is achieved. However, this progress has not been uniform: high-profile failures, including the crenezumab trials in autosomal-dominant Alzheimer's disease and the GRADUATE I/II gantenerumab studies (2022), failed to meet primary clinical endpoints, reinforcing the principle that robust fibrillar amyloid removal appears necessary—though not always sufficient—for clinical efficacy.

Alongside monoclonal antibody development, the field has moved decisively toward early, biomarker-guided intervention rather than late-stage disease reversal, reflecting the hypothesis that Alzheimer's dementia must be prevented rather than cured. Current trials increasingly enroll patients with early-stage disease or mild cognitive impairment, incorporating amyloid and tau pathology biomarkers, cerebrovascular assessment, and neurodegeneration markers into diagnostic frameworks. A major methodological advance has been the refinement of clinical trial enrichment strategies: combining digital memory assessments with plasma phosphorylated tau 217 (pTau217) has proven capable of identifying preclinical AD participants at highest risk of progression, reducing required sample sizes by as much as 75% (from 3,252 to 818 participants per arm) and enabling smaller, shorter, and more cost-efficient trials. This diagnostic sophistication is complemented by exploration of scalable, non-invasive plasma-based biomarkers intended to transform real-world diagnostic workflows, alongside emerging therapeutic candidates such as Dl-3-n-butylphthalide (NBP), which has shown cognitive benefit through multi-target mechanisms including reduced neuroinflammation and oxidative stress.

Beyond individual trial outcomes, published data increasingly emphasize the systemic and societal implications of this evolving landscape. Modeling analyses suggest that slowing disease progression could meaningfully reduce long-term care needs, care-partner burden, and associated costs, while population-level projections indicate substantial potential gains in quality-adjusted life years and modest reductions in health inequities under expanded treatment access scenarios. At the same time, health system preparedness research—particularly across major European markets—highlights the infrastructure and resource adjustments required to support biomarker-based screening and timely treatment delivery at scale. Collectively, the past five years reflect a transition from a syndrome-based, symptom-focused approach to an increasingly precision-guided, biomarker-driven treatment paradigm, with future directions centered on optimizing anti-amyloid antibody delivery, advancing tau-targeted therapies, and translating trial-level efficacy into real-world clinical benefit.

Kisunla's Maintenance Strategy: A New Chapter in AD Care

The landscape of Alzheimer's disease (AD) treatment is undergoing a profound transformation, driven by the advent of anti-amyloid monoclonal antibodies. These therapies, including donanemab (Kisunla), have demonstrated a remarkable ability to clear amyloid-beta plaques from the brain, offering the first true disease-modifying approach for early AD. However, the journey doesn't end with initial clearance. Research indicates that amyloid plaques can reaccumulate at a rate of approximately 2.8 Centiloids per year once active treatment ceases, posing a significant challenge to maintaining long-term therapeutic benefits.

Eli Lilly's initiative to explore a maintenance therapy for Kisunla, specifically a once-a-year 1,400 mg dose, marks a pivotal strategic evolution. This move aims to sustain amyloid negativity, addressing a critical unmet need and offering a potential competitive advantage in a crowded market. For patients and caregivers, a once-a-year infusion could dramatically reduce treatment burden and improve adherence, enhancing the overall value proposition of Kisunla. This approach could solidify Kisunla's position by providing a comprehensive, long-term management solution for AD.

However, this innovative strategy is not without its considerations. The long-term safety profile of maintenance dosing, particularly regarding the cumulative risk of amyloid-related imaging abnormalities (ARIA), will be paramount. Furthermore, the cost-effectiveness of extending treatment indefinitely, even at a reduced frequency, will be a significant factor for healthcare systems and payers already grappling with the high price tags of these therapies. Interestingly, some quantitative models suggest much longer intervals, such as 64 months, might be sufficient to maintain amyloid negativity, raising questions about the optimal frequency for maintenance. As the field progresses, balancing sustained efficacy, patient convenience, safety, and economic viability will be crucial in shaping the future of AD care.