Sept 25 (Reuters) - Eli Lilly ( LLY ) said on Thursday

the U.S. Food and Drug Administration has approved its treatment

for a form of advanced breast cancer in patients who have

received prior therapy.

The therapy, Inluriyo, was approved based on data from a

late-stage trial in which patients had a 38% lower chance of

their cancer progressing or death compared to those on standard

treatments, the drugmaker said.

Metastatic breast cancer, also called Stage IV breast

cancer, occurs when the disease has spread beyond the breast and

nearby lymph nodes to other parts of the body, most commonly the

bones, lungs, liver or brain.

Some breast cancers develop ESR1 mutations, which make

estrogen receptors overly active. These receptors normally help

regulate cell growth, but when mutated, they can drive cancer

progression.

Inluriyo is designed to target these overactive receptors by

binding to the estrogen receptor, blocking its activity and

breaking it down to help slow the spread of the disease.

The therapy is expected to be available in the United States

in the next few weeks, the company said.

Its label includes a warning for embryo-fetal toxicity which

refers to potential harm to developing embryos and fetuses

caused by exposure during pregnancy.

In the late-stage trial, patients on Inluriyo went 5.5

months on an average without their cancer worsening, compared to

3.8 months with other treatments, the company said.

The once-daily oral therapy is recommended at a dose of 400

mg, administered as two 200 mg tablets taken on an empty stomach

- either two hours before or one hour after a meal.

The drug is also being tested in a late-stage trial in

combination with Eli Lilly's ( LLY ) abemaciclib for advanced breast

cancer and as an adjuvant therapy in early-stage disease.