• Earlier in May 2026, Biogen reported topline Phase 2 CELIA data for diranersen in early Alzheimer’s disease, showing robust tau reductions and signals of slowed cognitive decline despite missing the primary dose‑response endpoint, and confirmed plans to move the first-in-class tau-targeting antisense therapy into registrational development.
• The decision to advance diranersen underscores how Alzheimer’s R&D is broadening beyond amyloid, with tau and other pathways paving the way for future combination treatment approaches as three-quarters of current trials now target mechanisms outside traditional amyloid and tau biology.
• Next, we’ll examine how Biogen’s decision to progress diranersen toward registrational trials could reshape its investment narrative around Alzheimer’s innovation.

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Biogen Investment Narrative Recap

To own Biogen today, you need to believe that newer neurology launches and Alzheimer’s innovation can steadily offset pressure on aging MS and other legacy products. The CELIA readout for diranersen adds a potential second Alzheimer’s pillar beside LEQEMBI but does not change that the key near term catalyst is still LEQEMBI’s commercial and label progress, while the biggest current risk remains overreliance on a handful of high priced therapies facing payer and competitive pressure.

Against that backdrop, the most relevant recent announcement is Biogen’s plan to move diranersen into registrational development after the Phase 2 CELIA trial showed robust tau reductions and signs of slowed cognitive decline despite missing its primary endpoint. This positions diranersen as a longer dated catalyst that could, over time, diversify Biogen’s Alzheimer’s franchise beyond amyloid and partially mitigate the risk that LEQEMBI, SKYCLARYS and ZURZUVAE carry an outsized share of the growth burden.

Yet despite this progress, investors should also be aware that payer pushback and pricing pressure could still...

Biogen’s narrative projects $9.4 billion in revenue and $2.1 billion in earnings by 2028.

Uncover how Biogen's forecasts yield a $205.67 fair value, a 8% upside to its current price.

Exploring Other Perspectives

Some of the lowest analysts were already assuming Biogen’s revenue could slip to about US$8.6 billion by 2029 and still saw earnings at roughly US$1.9 billion, so if you are encouraged by diranersen’s Phase 2 signal, it is worth comparing that cautious view on pricing and Alzheimer’s trial risk with your own expectations before deciding how this new data might shift the story.

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The Verdict Is Yours

Don't just follow the ticker - dig into the data and build a conviction that's truly your own.

• A great starting point for your Biogen research is our analysis highlighting 2 key rewards and 1 important warning sign that could impact your investment decision.
• Our free Biogen research report provides a comprehensive fundamental analysis summarized in a single visual - the Snowflake - making it easy to evaluate Biogen'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.