After doubling sales of its Biogen-partnered Alzheimer’s disease med Leqembi in its 2025 fiscal year, Eisai figures the crawl to its blockbuster ambitions will hit a stride in 2026, when it expects to circle $900 million in annual sales of the drug.
In the three years since the amyloid beta-confirming directed antibody hit the scene, sales have been off to a relatively slow start. After its FDA approval in 2023, the drug generated 44.3 billion yen ($279 million) in Eisai’s 2024 fiscal year and 88 billion yen ($554.6 million) last year. Eisai’s fiscal years run from the start of April to the end of March each year.
Now, Eisai is banking on 143.5 billion yen ($904.6 million) in fiscal 2026 Leqembi revenues, the company said in its full-year earnings presentation (PDF) on May 15.
Most of the growth is expected to come from the North American market, which represented 44.6 billion yen ($281 million) in sales in 2025. In the U.S. and other regions, Leqembi is the “top brand” for early Alzheimer’s disease treatment, CEO Haruo Naito emphasized on the company’s earnings conference call with investors. Naito explained that Leqembi’s sales are surging above that of the “second brand” in both the U.S. and Japan, referring to Eli Lilly’s rival treatment Kisunla.
Since launching Leqembi in 2023, Eisai has spent “all our efforts” on boosting awareness of the importance of early initiation and long-term continuation of the treatment, Naito said. In the U.S., 72% of patients continue with Leqembi after 18 months, as do 67% after two years, the executive explained, pointing to real-world U.S. long-term persistence data.
The two key bottlenecks that the company has long attributed to stifling further Leqembi growth manifest in the amyloid-beta confirming diagnoses needed to receive the med and the burdens associated with the infusion-based treatment. To overcome these challenges, Eisai is building out a “fundamental transformation” based on two technological innovations that the company refers to as “revolutionary.”
For one, the company looks to simplify the diagnostic process by relying on blood-based biomarker (BBM) tests. In 2025, some 15% of confirmatory diagnoses were performed using this measure, marking a 12-fold increase since the start of 2024, according to Eisai. With more BBM-based diagnostic measures expected to be approved in 2026, the company predicts that the tests will account for more than half of all amyloid-beta confirmatory diagnoses in its 2028 fiscal year.
Meanwhile, the August approval of Eisai and Biogen’s Leqembi Iqlik autoinjector for once-weekly maintenance dosing sparked an increase in new patients for both the IV and Iqlik versions, Eisai explained in its presentation.
This summer will see FDA action on the autoinjector as an initiation treatment, with additional approvals also expected in Japan and China this year. The company figures that the option of initiating treatment with the at-home, more convenient autoinjector could expand Leqemebi’s treatment population to those who previously opted against the therapy, it said.
Eisai has already set high aspirations for Leqembi’s growth path, last year predicting its 2027 fiscal year to result in blockbuster sales of 250 to 280 billion Japanese yen ($1.6 billion to $1.8 billion). As for 2026, the fiscal year will see Leqembi entering its “true expansion phase,” Eisai said in its recent earnings update.
Driven by its trio of kinase inhibitor Lenvima, insomnia treatment Dayvigo and Leqembi, Eisai’s pharma-specific revenue reached 810.8 billion yen ($5.1 billion) over 2025’s fiscal year, marking 8% growth from the previous year. The company achieved “record-high” revenue across its overall business, pulling in 825.4 billion yen ($5.2 billion) in 5% growth, despite a decline in operating profit.