Thoughts into Alz Ph2 data at AAIC and Model Refresh

Research evidence excerpt

Thoughts into Alz Ph2 data at AAIC and Model Refresh

IdeaM

Model Changes and Catalyst calendar

Model Updates: We update our BIIB model to reflect the recently closed Apellis

transaction (sales and expenses), we increase COGS related to Leqembi, consistent with

the MS Japan Pharma team's Eisai note (LINK) and tweak our Felza estimates.

On the acquired APLS assets, we forecast 2030/2035 sales for Empaveli (PHN & CG3 and

IC-MPGN) of $636mn/$584mn and for Syfovre (GA) of $759mn/$805mn. We take a more

conservative view of Syfovre given our view of outstanding questions on benefit/risk

profile.

We raise our 2026 and 2027 Leqembi COGS ratio assumptions to 40% from 30%

previously, reflecting the company's higher COGS margin expectation, before gradually

improving back to 30% from 2031 onward.

Separately we raise our Felza risk adjusted outer year sales on the AMR opportunity - our

2035 risk adjusted sales go to ~$1.5bn from ~$1.0bn. This is based on an assumption of 11k

AMR patients per year, consistent with recent mgmt commentary, a net price of $312k,

and AMR penetration rates above IgAN given less competition. We apply a 70% PoS to

both the AMR and IgAN indications.

As a result of these changes our 2026-2030 revenue CAGR goes to 1.4% from -1.2%.

Our BIIB price target increases to $224 from $206. We derive our $224 price target

from a discounted cash flow (DCF) analysis using a 10% discount rate (unchanged) and 2%

terminal growth (unchanged).

Exhibit 3: BIIB Catalyst Calendar

Company Timing Drug Event

BIIB 7/12-15/26 BIIB080 (anti-tau ASO) Ph2 Alzheimer's data (CELIA trial) at AAIC

BIIB 8/24/26 Leqembi FDA action on SQ formulation induction

APLS 2H26 APL-9099 IND for IgG-mediated autoimmune diseases

BIIB 4Q26 Litifilimab Ph3 SLE data (TOPAZ-1 &-2 Trials)