Eli Lilly's Kisunla Gains FDA Approval for New Dosing Regimen, Addressing Safety Concerns in Alzheimer's Treatment

Eli Lilly's Alzheimer's drug Kisunla has received a significant boost from the U.S. Food and Drug Administration (FDA) with the approval of a new dosing regimen designed to mitigate safety concerns. This development marks a pivotal moment in the ongoing efforts to improve treatment options for early Alzheimer's disease while addressing the challenges associated with anti-amyloid antibody therapies.

New Dosing Schedule Aims to Reduce ARIA Risk

The FDA has greenlit a modified dosing schedule for Kisunla that could potentially lessen the incidence of amyloid-related imaging abnormalities (ARIA), a known side effect of monoclonal antibody drugs that has led to several deaths and hindered widespread adoption of these treatments.

Under the new regimen, Kisunla will be administered more gradually in the initial months of treatment. The updated dosing starts with 350 mg for the first infusion, followed by 700 mg for the second, and 1,050 mg for the third, before reaching the full 1,400 mg monthly dose. This approach contrasts with the original schedule, which began with 700 mg doses for the first three months before escalating to 1,400 mg.

The TRAILBLAZER-ALZ 6 study, which underpinned this label update, demonstrated a significant reduction in ARIA with edema (ARIA-E) incidents. By week 24, the incidence of any ARIA-E decreased to 14% with the new regimen, compared to 24% with the original dosing, representing a 41% lower risk. At 52 weeks, the risk reduction remained substantial at 35%.

Dr. Brandy Matthews, Vice President of Global & US Medical Affairs for Alzheimer's disease at Eli Lilly, stated, "This label update will aid healthcare professionals in evaluating appropriate treatment options for their patients."

Efficacy Maintained with Improved Safety Profile

Crucially, the modified dosing regimen maintained Kisunla's efficacy in removing amyloid plaques. The TRAILBLAZER-ALZ 6 study showed that patients on the new regimen experienced an average 67% reduction in amyloid plaques at 24 weeks, compared to 69% with the original dosing.

The study also revealed a decrease in severe ARIA-E events, with no cases of radiographically severe ARIA-E reported in the modified titration group. This stands in contrast to the two cases observed with the original regimen in the phase 3 TRAILBLAZER-ALZ 2 study.

Market Challenges and Future Prospects

Despite the promise of these new Alzheimer's treatments, both Kisunla and its competitor, Eisai and Biogen's Leqembi, have faced challenges in market adoption. In the first quarter of 2025, Kisunla recorded global sales of $21.5 million, while Leqembi reported $96 million.

The approval of these drugs has, however, stimulated investment in the Alzheimer's space. Global Data reports that deal value for Alzheimer's-focused companies surged from $2 billion in 2022 to $18 billion in 2024, marking a 780% increase.

As the industry awaits results from the TRAILBLAZER-ALZ 3 trial, which is evaluating Kisunla in preclinical Alzheimer's, analysts at Jefferies suggest this could be "THE most important trial in terms of changing the treatment paradigm for Alzheimer's." The study, currently slated for primary completion in 2027, may potentially read out earlier due to its event-driven nature.