Biogen Inc.: Anti-tau intrigues but messy outcomes complicate picture; Thoughts on CELIA

Research evidence excerpt

Biogen Inc.: Anti-tau intrigues but messy outcomes complicate picture; Thoughts on CELIA

Accessible version

Biogen Inc.

Anti-tau intrigues but messy outcomes

complicate picture; Thoughts on CELIA

Maintain Rating: NEUTRAL | PO: 203.00 USD | Price: 191.92 USD

Reasons for optimism but mixed signals open debate 14 May 2026

This morning, Biogen reported qualitative top-line results from CELIA, its phase 2 of Equity

anti-tau ASO diranersen (BIIB080) for Alzheimer’s (AD; partnered with Ionis, covered by

Jason Zemansky

Jason Gerberry), marked by a mix of encouraging signals but plenty of questions likely to Research Analyst

keep investors cautious. It’s admittedly hard to know what to make of the inconsistent BofAS jason.zemansky@bofa.com

trends—complicated by the lack of numbers—and we suspect bulls and bears alike are

Jacqueline Plesset

anchoring to their existing views, contributing to BIIB share weakness (-6% vs. NBI -1%). Research Analyst

BofAS

Biogen, for its part, emphasized the positives: trends toward cognitive benefit and a jacqueline.plesset@bofa.com

reduction in tau pathology, and in a disease area marked by frustratingly limited

progress, we think there are at least reasons to be encouraged by the potential of a new

MoA. That said, the inverse dose response/ miss on the primary endpoint is worrisome, Stock Data

and especially in a field weighed by repeated multiple disappointments, we wouldn’t be

surprised if many investors take a wait-and-see approach. For these reasons, we expect Price 191.92 USD

the debate to continue, likely well beyond the full data presentation at AAIC (July 12-15; Price Objective 203.00 USD

London). In the meantime, given the lack of clarity, we think the risk/reward remains Date Established 29-Apr-2026

balanced.