Biogen's (BIIB) potential Alzheimer's disease drug Leqembi has "meaningful advantages" over Eli Lilly's (LLY) Kisunla that could help surpass its rival, RBC Capital Markets said in a note to investors on Friday.

While Kisunla is being developed and tested more quickly, Leqembi's subcutaneous administration and "cleaner safety" could help it gain a significant foothold in a US market with up to 15 million patients and more than $4 billion in sales, the note said.

"At a penetration of 5%, 50/50 market share split with Kisunla, and similar pricing as in early Alzheimer's disease, we estimate this segment could add another $6B in sales in the US alone," the note said.

Two Leqembi studies are expected to produce results in 2028, the note said.

RBC gave Biogen an "outperform" rating with a price target of $213.