ParfumGigi@aol.com

By Ransdell Pierson

NEW YORK (Reuters) - A new type of treatment for advanced breast cancer could win U.S. approval this week and offer an option for patients whose cancer has continued to spread despite treatment with existing therapies.

The medicine, called ixabepilone, could generate annual sales of $500 million by 2012 and help Bristol-Myers Squibb reclaim a leadership role in oncology, according to industry analysts.

An estimated 160,000 women, and a relatively small number of men, in the United States are diagnosed with breast cancer each year. About 40,000 die of the disease despite treatment with leading current drugs such as Bristol's older Taxol, Sanofi-Aventis' Taxotere and Roche Holding AG's Xeloda.

"Although three-fourths of breast cancer patients are responding well to existing tools, many are developing very advanced and protracted cancer because their tumors have developed resistance to existing drugs," Renzo Canetta, a senior Bristol-Myers research official, said in an interview.

The New York-based company has asked the U.S. Food and Drug Administration to approve ixabepilone as a stand-alone treatment, or in combination with Xeloda, for patients whose breast cancer has spread despite prior treatments.

Among patients taking it with Xeloda in clinical trials, tumors either shrank or did not grow for an average of 5.8 months. That was a statistically significant improvement compared to the 4.2 months seen for patients taking only Xeloda.

Two ongoing trials are expected to determine by late 2008 whether ixabepilone actually prolongs survival, Canetta said.

"If the data show a survival benefit, that would make it more compelling to use against earlier-stage breast cancer," he said.

Bristol-Myers had been the world's biggest seller of oncology drugs until 2000, when its U.S. patent on Taxol lapsed and cheaper generic forms of the then-blockbuster chemotherapy flooded the market. It is now eclipsed by Roche and Genentech Inc and their highly effective biotech medicines.

"In the past, when we were No. 1 in oncology. We were known for developing other people's drugs, but we are now discovering and developing our own," Canetta said.

For instance, Bristol discovered and tested the company's recently approved Sprycel leukemia drug and is studying a number of other compounds from its own laboratories, he said.

"A very clear strategic decision was made five to eight years ago to recommit ourselves to oncology, with a goal of dramatically increasing our ability to discover drugs," Canetta said.

But one of Bristol-Myers' most promising experimental cancer drugs, a treatment for melanoma called ipilimumab, is being developed in partnership with Medarex Inc.

Bristol aims to seek U.S. approval early next year for use of the drug to treat the dangerous form of skin cancer among patients whose tumors have spread.

Instead of directly killing tumors, the drug is designed to coax creation of more T-cells -- immune system soldiers that seek out and attack substances deemed "foreign" to the body.

Canetta said tumors shrank among 15 to 20 percent of patients in clinical trials, with about half of those "responders" having a complete disappearance of their melanoma.

A leading current treatment for metastatic melanoma, Proleukin sold by Novartis AG, also shrinks tumors in about 15 percent of patients.

"(But) it causes a flu-like syndrome and fewer patients have a complete response," Canetta said, meaning a complete disappearance of cancer.

Next in line at Bristol-Myers is a cancer drug called vinflunine, which recently completed trials as a treatment for bladder cancer. Canetta said the company would decide by the end of the year whether to seek approval for the compound.