Initial take on Diranersen Ph2 Alz tau data at AAIC

Research evidence excerpt

Initial take on Diranersen Ph2 Alz tau data at AAIC

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July 14, 2026 02:28 PM GMT

Morgan Stanley & Co. LLCMBiogen Inc | North America Terence C Flynn, Ph.D.

Equity Analyst

Initial take on Diranersen Ph2 Terence.Flynn@morganstanley.comConnor M Massari +1 212 761-2230

Connor.Massari@morganstanley.com +1 212 761-2417

Alz tau data at AAIC Chris Yu, J.D., Ph.D.

Chris.L.Yu@morganstanley.com +1 212 761-2535

Investigators presented full data for BIIB's diranersen (BIIB080; anti-tau ASO)

Alexander Yevdokimov, Ph.D.

Ph2 Alzheimer's trial at the AAIC conference and we offer our key takeaways Research Associate

below. Alexander.Yevdokimov@morganstanley.com +1 212 761-2167

Hailey Horowitz

See our prior note on our outstanding questions HERE, and our CDI preview note ResearchHailey.Horowitz@morganstanley.comAssociate +1 212 761-5264

HERE. We see the Ph2 data as most similar to our Scenario 2 (still no credible Damien H Kerner

explanation for lack of dose response, but data generally consistent with prior Research Associate

Damien.H.Kerner@morganstanley.com +1 212 761-3829

topline commentary), but note the 60mg dose efficacy - slowing of CDR-SB (0.54

Morgan Stanley India Company Private Limited+

vs. placebo) was toward the lower end of the expectation range and hence could

Saket Agarwal

explain the weakness in BIIB shares. During Q&A the investigator at AAIC noted Research Associate

there's a need to understand the dose response situation better. Saket.Agarwal@morganstanley.com +91 22 6995-4012

The trial explored 3 diranersen doses - 60mg Q24W (total yearly dose of ~120mg), Biogen Inc (BIIB.O, BIIB US)

115mg Q24W (total yearly dose of ~230mg), and 115mg Q12W (total yearly dose of Biotechnology | United States of America

~460mg) - vs. placebo. Stock Rating Equal-weight