April 23 (Reuters) - The U.S. Food and Drug

Administration has approved Regeneron's gene therapy

for a rare genetic form of deafness, the company said on

Thursday.

This approval, granted under the FDA's new priority voucher

program, marks the introduction of the first gene therapy for

genetic hearing loss to the market.

Regeneron said the therapy Otarmeni will be available for

free to patients in the United States. Regeneron is also set to

announce a drug pricing deal with the White House this

afternoon.

The gene therapy targets otoferlin-related hearing loss, a

condition caused by variants in the OTOF gene that affects 20-50

newborns in the U.S. each year.

Otoferlin is a critical protein in the ear's inner hair

cells, essential for transmitting sound signals to the brain.

The therapy delivers a working copy of the OTOF gene to

replace the non-functional otoferlin protein using a modified,

non-pathogenic virus, delivered via an infusion into the cochlea

- a bony cavity within the inner ear.

China's Refreshgene and Eli Lilly ( LLY ) have also been

studying therapies for the condition that have restored hearing

in children in early trials.

"I'd say for the field, it means a new era and thinking

about treatments for hearing loss - this is just the beginning,"

said Jonathon Whitton, vice President, auditory global program

head at Regeneron.

Travis Smith, born six weeks early and diagnosed with the

OTOF mutation, received Regeneron's experimental therapy at 18

months as part of a clinical trial.

"Watching him be able to interact with other children and

even him knowing his name now and turning when I say his name is

the craziest thing," said two-and-a-half-year-old Travis' mother

Sierra, whom Reuters contacted through Regeneron.

"I can tell him how much I love him - it's such a different

world."