The health ministry on Monday granted full approval to lecanemab, the much-hyped drug for Alzheimer's disease, but experts point out there are big challenges ahead, particularly on how to control side effects such as brain swelling and bleeding.

The approval of lecanemab, the first drug seen to slow the progression of the neurodegenerative disease, follows August’s greenlighting of the drug by a ministry panel. The rollout of the medication, to be sold as Leqembi, could begin by the end of the year, pending a pricing decision by another health ministry committee.

Japanese drugmaker Eisai and U.S. firm Biogen developed the antibody treatment to remove — and prevent the buildup of — the amyloid beta protein in the brain, which is linked to the death of brain cells.