May 1 (Reuters) - Biogen beat first-quarter

profit and revenue expectations on Thursday, as strong demand

for its rare disease drugs helped offset declining sales of its

multiple sclerosis medicines.

The drugmaker has focused on deals, cost-cutting measures

and newer drugs to address investor pressure for growth as

demand falls for its once top-selling multiple sclerosis

medicines in the face of stiff competition in a crowded

treatment market.

The "relatively calm quarter" for Biogen showed positive

signs of improvement, said BMO Capital Markets analysts.

Biogen has been doubling down on its Alzheimer's drug

Leqembi, but it has failed to live up to lofty expectations due

to concerns over cost, efficacy and side effects. It sells for

$26,500 annually in the U.S.

The drugmaker said it does not expect any material impact

this year from the Trump administration's sweeping tariffs

implemented so far to boost domestic manufacturing of goods.

Biogen said about 75% of its U.S. revenue last year came

from products manufactured in the country. Drugs primarily

manufactured in the U.S. include Leqembi and spinal muscular

atrophy treatment Spinraza.

The company expects 2025 profit per share of $14.50 to

$15.50, compared with its previous forecast of $15.25 to $16.25.

The forecast cut reflects a $165 million charge related to

its licensing deal with Stoke Therapeutics ( STOK ) earlier this

year.

It reported quarterly adjusted profit of $3.02 per share,

beating analysts' expectations of $2.52 per share, according to

estimates compiled by LSEG.

U.S. sales of Leqembi, which the company sells with Japan's

Eisai ( ESALF ), were $52 million for the first quarter. The Wall

Street consensus estimate was at $51 million, according to

brokerage Jefferies.

First-quarter sales of its multiple sclerosis drugs fell 11%

to $953 million, while sales of rare disease drugs, including

Skyclarys and Spinraza, jumped 33% to $563 million.

Revenue rose 6% to $2.43 billion, and beat expectations of

$2.23 billion.

(Reporting by Christy Santhosh and Mariam Sunny in Bengaluru;

Editing by Devika Syamnath)