Biogen (BIIB) and Eisai said Sunday that data presented at the Alzheimer's Association International Conference 2026 showed the subcutaneous autoinjector formulation of Leqembi achieved efficacy and safety comparable to the intravenous formulation in patients with early Alzheimer's disease.

The companies said once-weekly 500 mg subcutaneous Leqembi demonstrated bio-equivalent drug exposure to the approved intravenous initiation regimen, supporting comparable amyloid clearance, clinical efficacy and safety regardless of the route of administration.

If approved by the US Food and Drug Administration, the formulation could provide a more convenient at-home alternative to intravenous infusions for treatment initiation, the companies said.