How New Long-term Leqembi Data And At-home Injections At Eisai (TSE:4523) Have Changed Its Investment Story

• Eisai and Biogen recently presented new long-term data at the CTAD 2025 conference showing that Leqembi (lecanemab) treatment, including a subcutaneous autoinjector formulation, may substantially delay progression from mild cognitive impairment to more advanced Alzheimer’s disease while maintaining a safety profile consistent with earlier trials.
• The findings that earlier and continued Leqembi use could translate into several additional years before patients reach moderate Alzheimer’s stage, combined with at-home subcutaneous dosing that appears clinically equivalent to intravenous infusion, materially strengthen the real-world treatment case for Eisai’s Alzheimer’s franchise.
• We’ll now examine how the promising long-term “time savings” data and convenient at-home Leqembi injections may reshape Eisai’s investment narrative.

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Eisai Investment Narrative Recap

To own Eisai, you need to believe its Alzheimer’s portfolio can justify today’s premium valuation despite pricing pressure and intense competition. The new CTAD data, highlighting meaningful “time savings” and convenient at-home Leqembi injections, reinforces the near term catalyst around U.S. and Japan subcutaneous approvals, while the biggest risk remains overreliance on Leqembi amid regulatory and reimbursement uncertainty.

The most relevant recent update is Eisai’s completion of the rolling sBLA for Leqembi Iqlik, seeking U.S. approval for at-home subcutaneous initiation dosing. Combined with the CTAD time savings data, this filing shapes expectations for how quickly Eisai can convert clinical momentum into broader real world uptake, against the backdrop of drug pricing pressure and competing Alzheimer’s programs.

Yet while the long term data look encouraging for Leqembi’s role in early Alzheimer’s treatment, investors should also be aware that...

Read the full narrative on Eisai (it's free!)

Eisai's narrative projects ¥897.0 billion revenue and ¥66.6 billion earnings by 2028.

Uncover how Eisai's forecasts yield a ¥5012 fair value, a 8% upside to its current price.

Exploring Other Perspectives

Two fair value estimates from the Simply Wall St Community span roughly ¥5,012 to ¥6,739 per share, underscoring how far apart individual views can be. Set against this, the key near term question is how much the stronger Leqembi “time savings” data and pending subcutaneous approvals can offset pricing pressure and Eisai’s heavy reliance on a single Alzheimer’s franchise.

Explore 2 other fair value estimates on Eisai - why the stock might be worth as much as 45% more than the current price!

Build Your Own Eisai Narrative

Disagree with existing narratives? Create your own in under 3 minutes - extraordinary investment returns rarely come from following the herd.

• A great starting point for your Eisai research is our analysis highlighting 3 key rewards and 1 important warning sign that could impact your investment decision.
• Our free Eisai research report provides a comprehensive fundamental analysis summarized in a single visual - the Snowflake - making it easy to evaluate Eisai's overall financial health at a glance.

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This article by Simply Wall St is general in nature. We provide commentary based on historical data and analyst forecasts only using an unbiased methodology and our articles are not intended to be financial advice. It does not constitute a recommendation to buy or sell any stock, and does not take account of your objectives, or your financial situation. We aim to bring you long-term focused analysis driven by fundamental data. Note that our analysis may not factor in the latest price-sensitive company announcements or qualitative material. Simply Wall St has no position in any stocks mentioned.

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