Biogen's Leqembi Gains Ground as Novo Nordisk's GLP-1 Fails in Alzheimer's Trials

Biogen's Alzheimer's drug Leqembi (lecanemab) is poised for increased uptake following the failure of Novo Nordisk's semaglutide in two pivotal Phase III trials for Alzheimer's disease progression. This development removes a perceived competitive threat and solidifies the position of anti-amyloid antibodies as the primary disease-modifying treatment option in the Alzheimer's market.

Semaglutide Trial Results and Market Implications

Novo Nordisk recently announced that semaglutide, a GLP-1 receptor agonist, did not meet its primary endpoint in the EVOKE and EVOKE+ Phase III trials for reducing Alzheimer's disease progression. This outcome has significant implications for the Alzheimer's treatment landscape:

• Analysts from Jefferies and Stifel agree that the failure removes a "modest" or "perceived" overhang on Biogen and the anti-amyloid antibody class.
• The competitive landscape for Alzheimer's treatments has softened, potentially accelerating sales of Leqembi and Eli Lilly's Kisunla (donanemab).
• Biogen's stock responded positively, rising 2.6% to $179.75 per share as markets opened following the announcement.

Despite the primary endpoint failure, Novo Nordisk reported improvements in Alzheimer's disease-related biomarkers in both trials. The company is expected to present topline results at the upcoming Clinical Trials on Alzheimer's Disease (CTAD) conference in San Diego on December 3, 2025.

Leqembi's Recent Advancements and Future Prospects

Leqembi, co-developed by Biogen and Eisai, has made significant strides in expanding its market presence:

• The FDA approved Leqembi Iqlik, a subcutaneous formulation, in September 2025, with the launch following in October.
• BMO Capital Markets suggests that the subcutaneous formulation could expand access to Leqembi as more patients transition to longer-term treatment.
• Biogen anticipates an FDA decision on a subcutaneous induction formulation of Leqembi, with Jefferies projecting approval by mid-2026.

Looking ahead, the AHEAD 3-45 study is investigating Leqembi in people with preclinical Alzheimer's and elevated or intermediate amyloid levels. Results from this trial are expected no earlier than 2028, according to Jefferies analysts.

Competitive Landscape and Future Readouts

The Alzheimer's treatment market remains dynamic, with key developments on the horizon:

• Eli Lilly's TRAILBLAZER-ALZ-3 study, examining Kisunla in patients with preclinical Alzheimer's disease, is set to conclude in November 2027. However, Jefferies anticipates data as early as late 2025 or the first half of 2026.
• Positive results from the TRAILBLAZER-ALZ-3 study could potentially de-risk the broader anti-amyloid class and provide a positive read-through for Leqembi's AHEAD 3-45 trial.
• RBC Capital Markets analysts suggest that the resolution of the semaglutide overhang could pave the way for appreciation in Biogen's value, particularly in anticipation of a more eventful late 2025 and 2026.

As the landscape for Alzheimer's treatments continues to evolve, the failure of Novo Nordisk's semaglutide trials has reinforced the position of anti-amyloid antibodies like Leqembi and Kisunla as the leading disease-modifying options for patients with Alzheimer's disease.