Oct 30 (Reuters) - Biogen beat Wall Street

estimates for third-quarter profit, helped by

better-than-expected sales of some of its multiple sclerosis

treatments.

The company, however, cut its annual profit forecast as

it expects to take a hit of $1.25 per share from research and

development charges related to certain acquisitions in the

fourth quarter.

Biogen said it is pursuing deals to build its

early-stage pipeline amid declining sales of its once

top-selling multiple sclerosis medicines in the face of stiff

competition in a crowded treatment market.

"We expect to announce at least another one, if not two,

further research-stage deals by the end of the year," CEO

Christopher Viehbacher said on a call to discuss results.

Biogen shares were up over 2% in afternoon trading.

Earlier this year, Biogen had

licensed Vanqua Bio's

experimental drug targeting inflammatory disorders for up

to $1.06 billion.

For the third quarter, Biogen reported steady growth for its

keenly watched Alzheimer's treatment, Leqembi, which has

struggled with a slow start due to concerns over cost, efficacy

and side effects.

Global sales of Leqembi, developed with Japan's Eisai ( ESALF )

, rose over 80% in the quarter to about $121 million

from a year earlier. Its U.S. sales grew nearly 10% to $69

million.

A weekly under-the-skin injection version of Leqembi

received U.S. approval in August, offering a convenient at-home

administration option for patients after an initial series of

intravenous infusions.

Biogen expects adjusted 2025 per-share profit of between

$14.50 and $15.00, down from its prior view of between $15.50

and $16.00.

It earned $4.81 per share for the quarter, topping

expectations of $3.88 per share.

Sales of multiple sclerosis drugs, including Vumerity, rose

nearly 1% to $1.06 billion, beating a combined estimate of

$950.69 million, according to estimates compiled by LSEG.

Its rare disease portfolio - which includes genetic disorder

drug Skyclarys and spinal muscular atrophy drug Spinraza -

brought in sales of $533 million in the quarter, up nearly 8%

from a year earlier.

(Reporting by Mariam Sunny and Christy Santhosh in Bengaluru;

Editing by Anil D'Silva and Maju Samuel)