Biogen splits revenue from Leqembi with co-developer Eisai equally, the latter reporting Q1 sales of $96m for the drug. The US, where Leqembi got a full approval in July 2023, accounted for $52m of those sales. Biogen has already secured key milestones for Leqembi this year. In January, the US Food and Drug Administration (FDA) approved maintenance dosing of Leqembi, a move expected to expand its market share. Then in April, the Leqembi was authorised for use in the European Union (EU).