By Mariam Sunny

Aug 29 (Reuters) - The U.S. Food and Drug Administration

has approved an injectable version of Eisai ( ESALF ) and

Biogen's Alzheimer's disease drug Leqembi, the

companies said on Friday, allowing for an easier treatment

option following an initial intravenous infusion.

The approval makes Leqembi the first Alzheimer's treatment

that can be administered at home as a weekly under-the-skin

injection, reducing the hassle for patients who now need to

travel to an infusion center twice a month for the process that

takes about an hour.

The potential for at-home administration could also increase

the treatment's availability for other patients, Lynn Kramer,

chief clinical officer at Eisai ( ESALF ), told Reuters ahead of the

decision.

"It actually may open up more infusion chairs for even

greater initiation of the therapy for patients," Kramer said.

The injectable version, branded as Leqembi IQLIK, was

approved as a maintenance dose for patients who have completed

18 months of bi-weekly intravenous (IV) infusions, the companies

said.

Patients would also have the option to continue IV infusions

once every month as maintenance instead of the weekly

subcutaneous injection.

The companies said Leqembi IQLIK would be launched to

patients by October 6 at an annual list price of $19,500 for the

360 mg single-dose prefilled autoinjectors.

Biogen has been counting on the expanded approval to

strengthen the adoption of Leqembi, which is gaining momentum

after a slow start in the U.S.

The treatment struggled as the small cognitive benefit could

not convince prescribing doctors to overlook the hefty price

tag, twice-monthly infusions and regular brain scans to guard

against potentially lethal side effects.

Leqembi and rival Eli Lilly's ( LLY ) Kisunla are designed

to clear sticky deposits of a protein called amyloid beta, a

hallmark of Alzheimer's disease.