Biogen revealed Phase 2 CELIA trial data that sent BIIB shares down approximately 6.4% in a single session.

Biogen Inc. (NASDAQ: BIIB) shareholders lost approximately 6.4% of their investment value on May 14, 2026, when the company disclosed that its Phase 2 "CELIA" trial for Alzheimer's candidate diranersen (BIIB080) failed to meet its primary dose-response endpoint. Investors who lost money on BIIB are encouraged to submit their information for a free evaluation. You may also contact Joseph E. Levi, Esq. via email at jlevi@levikorsinsky.com or by telephone at (212) 363-7500.

The CELIA data disclosed on May 14 showed that diranersen did not meet its primary endpoint. BIIB shares fell approximately 6.4% in a single trading session following the announcement. Levi & Korsinsky is investigating whether Biogen's SEC filings adequately disclosed material information available to the company at the time of filing.

Shareholders who suffered losses on their Biogen investment are encouraged to contact Levi & Korsinsky before the investigation concludes. You may also reach Joseph E. Levi, Esq. via email at jlevi@levikorsinsky.com or by telephone at (212) 363-7500.

WHY LEVI & KORSINSKY -- Ranked in ISS Securities Class Action Services' Top 50 Report for seven consecutive years, Levi & Korsinsky, LLP is a nationally recognized leader in shareholder rights litigation. With a team of over 70 professionals, the firm has recovered hundreds of millions of dollars for investors.

Frequently Asked Questions About the BIIB Investigation

Q: Who is conducting the BIIB investigation? A: Levi & Korsinsky, LLP is investigating potential securities law violations on behalf of investors who purchased BIIB securities. The firm is nationally recognized, ranked in the ISS Top 50 for seven consecutive years, and has recovered hundreds of millions of dollars for aggrieved investors.

Q: Who is eligible to participate in the BIIB investigation? A: Investors who purchased BIIB stock or securities and suffered financial losses may be eligible. Eligibility is based on purchase date and documented losses -- not on whether you still hold the shares.

Q: What do BIIB investors need to do right now? A: Gather brokerage records including purchase dates, share quantities, and prices paid. Contact Levi & Korsinsky for a free, no-obligation evaluation at jlevi@levikorsinsky.com or (212) 363-7500. No immediate action is required to remain eligible to participate in the investigation.

Q: What if I already sold my BIIB shares -- can I still recover losses? A: Yes. Eligibility is based on when you purchased, not whether you still hold the shares. Investors who bought BIIB and sold at a loss may still participate in the investigation.

Q: What does it cost me to participate? A: Nothing. Securities investigations and any resulting actions are handled on a pure contingency basis. No upfront fees, no retainer, no out-of-pocket costs.

Q: Do I need to go to court or give testimony? A: No. Participating in the investigation does not require court appearances or depositions. If legal action is later pursued, the overwhelming majority of affected investors never appear in court either.

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