By Puyaan Singh and Leroy Leo

Aug 14 (Reuters) - The U.S. Food and Drug Administration

on Wednesday approved Gilead Sciences' ( GILD ) liver disease

treatment, Livdelzi, which it gained through a $4.3 billion

buyout of CymaBay Therapeutics earlier this year.

The disease, primary biliary cholangitis (PBC), causes

inflammation of the small bile ducts in the liver and can

eventually destroy them. It mainly affects women aged 35 to 60.

The American Liver Foundation estimates that about 65 out of

every 100,000 women in the U.S. have PBC.

Livdelzi's list price is $12,606 per 30 days of therapy.

Rival drug, Iqirvo, from Ipsen costs $11,500 per month.

BMO Capital Markets analyst Evan Seigerman sees $847 million

in annual peak sales for Livdelzi, accelerating growth for

Gilead's liver drug portfolio, which posted a 17% increase in

second-quarter revenue.

Gilead expects the drug to have modest sales in the first

couple of quarters, before sales become "much more meaningful in

2025 and beyond", Chief Commercial Officer Johanna Mercier told

Reuters.

Mercier said the drug was a "great strategic fit", given the

company's experience with liver disease treatments.

The FDA's accelerated approval for Livdelzi is based on a

193-patient study, in which 62% of the participants who received

a combination of the drug and ursodeoxycholic acid (UDCA) showed

an improvement in biochemical response after one year.

About 40% of PBC patients do not respond to the generic drug

UDCA as their first line of treatment, according to a study last

year.

Gilead's once-daily pill also showed a statistically

significant reduction in itching - a symptom that more than half

of the PBC patients experience.

Treatment with Ipsen's Iqirvo has also not shown

statistically significant reduction in itching, whereas

Intercept Pharmaceuticals' Ocaliva can worsen itching.

The FDA's accelerated nod to Livdelzi can be converted to a

standard approval if it shows improvement in survival or

preventing liver function deterioration in a confirmatory study.