Sell-Side Meeting Recap With BIIB Post-CELIA

Research evidence excerpt

Sell-Side Meeting Recap With BIIB Post-CELIA

Pharmaceuticals (Major) & Large Cap Biotechnology

Biotechnology-Large Cap - Market Weight

Sell-Side Meeting Recap With BIIB Post-CELIA May 14, 2026

Biogen (BIIB)

The Wolfe Byte

BIIB hosted a sell-side only call to discuss CELIA results for diranersen (BIIB080). We came away from the call

encouraged on clinical meaningfulness of the cognitive data; however, there are still questions on the lack of a dose

response and phase 3 design moving forward.

If replicated in a phase 3, BIIB would characterize the results as clinically meaningful. Our top takeaway from the call

with BIIB's Head of Development, Priya Singhal, is that if the cognitive benefit for diranersen (BIIB080) was replicated

in a phase 3, the result would be clinically meaningful. Importantly, BIIB also saw trends across all doses with the range

at or beyond that which was seen in successfully commercialized products.

Could the SAEs in the higher doses be driving the higher efficacy in the lower doses? We also inquired about the

inverse response seen with SAEs and efficacy; here, BIIB indicated that it was too early to conclude any causality. One

proposed hypothesis, however, was the existence of a tau threshold, beyond which it is no longer helpful to reduce tau

further. Regardless, based on the available data, BIIB stressed that the lowest dose, 60mg Q24W, has an attractive

benefit-risk profile.

Phase 3 considerations. During the call, questions came up on the phase 3 trial design, including the potential for

combinations with amyloid therapies (e.g., BIIB's Leqembi and Lilly's (LLY) Kisunla). Here, BIIB suggested they want to be

thoughtful, practical, and deliberate on how they design the phase 3, making sure the trial is not too complex, to allow for