BIIB - Quick Take - Tau Data: Consistent Efficacy Trends + Favorable Benefit/ Risk Support Moving Forward Despite Primary Miss

Research evidence excerpt

BIIB - Quick Take - Tau Data: Consistent Efficacy Trends + Favorable Benefit/ Risk Support Moving Forward Despite Primary Miss

Truist Securities

Equity Research Report May 14, 2026

HEALTHCARE: Biotech Biogen Inc. (BIIB)

BIIB - Quick Take - Tau Data: Consistent Efficacy Trends + Danielle Brill, Pharm.D.

212-303-4110 Favorable Benefit/ Risk Support Moving Forward Despite Primary

Danielle.Brill@truist.com Miss

Alex Nackenoff, Ph.D.

212-590-0908 Today, Biogen announced that the Phase 2 CELIA trial of diranersen (BIIB080) had missed

Alex.Nackenoff@truist.com its primary endpoint but believed there was sufficient evidence to justify advancing the asset

into pivotal development. Few details were provided in the release, but Biogen management

hosted a call with analysts to provide more color.

Current Price (May 13, $204.53 Key takeaways were: 2026)

Stock Rating HOLD 1. All doses showed trends of efficacy (across multiple measures), but primary endpoint was not met as it was evaluating dose-response changes in CDR-SB at 76-weeks. Unchanged

2. The most robust efficacy was observed in the lowest dose (60mg Q24W) cohort

Price Target $190.00 (which also enrolled 1/2 the number of patients vs the other higher dose arms). That

Unchanged said, based on management commentary we believe the cognitive benefits observed in

the low dose arm (1) were nominally stat-sig, (2) exceeded the magnitude of benefits

observed with the amyloid class, and (3) were "clinically meaningful."

3. While an inverse dose-response seems to have been observed, all dose cohorts 5 Page Document generated tau reductions about the targeted 50% threshold, and all doses

reportedly had an acceptable safety profile (albeit SAEs were the lowest in the low 60mg

Reasons for this report Q24W arm).