UPDATE 1-Eli Lilly wins U.S. approval for breast cancer drug

(Adds clinical trial, approval details, background, share price)

Sept 28 (Reuters) - The U.S. Food and Drug Administration said on Thursday it approved an Eli Lilly and Co drug to treat advanced breast cancer that has progressed following prior treatment.

The drug, abemaciclib, will be sold under the brand name Verzenio and will compete with Pfizer Inc's Ibrance and Kisqali from Novartis AG.

"Verzenio provides a new targeted treatment option for certain patients with breast cancer who are not responding to treatment, and unlike other drugs in the class, it can be given as a stand-alone treatment to patients who were previously treated with endocrine therapy and chemotherapy," Richard Pazdur, the FDA's head of oncology drug evaluation, said in a statement.

The Lilly drug and its rivals from Pfizer and Novartis belong to a newer class of oral medicines called CDK 4/6 inhibitors, which block cancer cells' ability to divide and proliferate.

In a pivotal clinical trial, abemaciclib when added to standard therapy reduced the risk of disease progression by 46 percent. It also led to significant tumor shrinkage in 59 percent of patients compared with 44 percent of those who received endocrine drugs alone in the study.

It was approved for adults who have hormone receptor HR-positive, HER2-negative advanced or metastatic breast cancer that has progressed after endocrine therapy that alters a patient's hormones, the FDA said.

An estimated 252,710 women will be diagnosed with breast cancer this year, and 40,610 will die of the disease, according to the National Institutes of Health. About 72 percent of patients with breast cancer have tumors that are HR-positive and HER2-negative.

Eli Lilly shares were up 76 cents, or 0.9 percent, at $85.40 in midafternoon trading on the New York Stock Exchange. (Reporting by Bill Berkrot; Editing by Tom Brown and Jonathan Oatis)