March 26 (Reuters) - The U.S. Food and Drug Administration approved Soleno Therapeutics' ( SLNO )

drug to treat a rare genetic disorder on Wednesday, making it the first treatment

available for patients who experience feelings of intense and persistent hunger.

Shares of the company were halted for trading.

The drug, branded as Vykat XR, received FDA's approval to treat Prader-Willi syndrome, a

genetic disorder caused by full or partial deletions on chromosome 15 that affect the regulation

of gene expression, or how genes turn on and off.

The debilitating condition, which affects about 50,000 people in the U.S., impacts several

everyday aspects of an individual's life, such as eating, behavior and mood.

It also slows down physical growth and intellectual development. Symptoms of the disease

become noticeable immediately after birth, with infants born with low muscle tone and an

inability to breastfeed.

As patients grow older, symptoms shift and children develop hyperphagia, the hallmark

symptom of the disorder, which causes a feeling of insatiable hunger and not feeling full after

eating. For some, this occurs as early as age four, and on average at about age eight and then

continues into adulthood.

The increased appetite can lead to rapid weight gain if not controlled, leading to obesity

and other related problems such as respiratory difficulties and heart disease.

The company estimates the average lifespan of people with the disease is between 21 and 29

years.

Soleno expects the drug to be available in the U.S., beginning in April 2025, to patients

aged four years and older with PWS who have hyperphagia.

The long-awaited approval comes after the FDA's extended review of the drug and mixed

results from a late-stage trial on its efficacy.