Biogen

Biogen is based in Cambridge, Massachusetts. Leqembi, the lecanemab antibody it shares with Eisai, is infused for early Alzheimer's and competes with Lilly's Kisunla, while the earlier Aduhelm launch was withdrawn.

Spinraza is the antisense drug for spinal muscular atrophy, infused in centers that also know Novartis's gene therapy Zolgensma and Roche's oral Evrysdi. The choice among those three is a specialist and payer decision made once, then lived with for years.

In multiple sclerosis, Tysabri and Vumerity still have patients, but Tecfidera's dimethyl fumarate is generic and Roche's Ocrevus took a large share of new starts. Infusion chairs, MRI monitoring, and prior authorization are the practical gates.

Leqembi demand depends on diagnostic capacity, infusion sites, and whether Medicare and private plans pay.

Spinraza competes with a one-time gene therapy and an oral drug, three modalities in one small population.

MS patients already on Tysabri are a sticky base, while new starts look first at Ocrevus.

Families seeking Leqembi need a confirmed diagnosis, a nearby infusion site, and a coverage approval.

SMA treatment is chosen by pediatric specialists, and switching modality later is clinically hard.