Bristol-Myers Squibb is celebrating the news that US regulators have given the green light to the company’s Ixempra, a first-in-class drug, as a treatment for advanced breast cancer.

Specifically, Ixempra (ixabepilone), an epothilone B semi-synthetic analogue, has been approved by the US Food and Drug Administration as a monotherapy to treat patients with metastatic or locally advanced breast cancer who have failed other chemotherapies, including an anthracycline, a taxane or Roche's Xeloda (capecitabine), and in combination with Xeloda. The approval is based on the analysis of two multi-centre, multinational trials that included 878 patients and the randomised Phase III trial of 752 patients demonstrated that Ixempra in combination with capecitabine resulted in a statistically significant improvement in progression-free survival compared to capecitabine monotherapy by a median of 5.7 months versus 4.1 months.

The approval came after the FDA granted priority review to ixabepilone in June and analysts believe that sales of this new chemotherapy, which is going to be available “within days” according to B-MS, will peak at around $400-$500 million sometime after 2010. Linda Vahdat at the New York-Presbyterian Hospital/Weill Cornell Medical Center said that the approval means that “we now have an important new option for patients with metastatic breast cancer who have rapidly progressed through currently approved chemotherapies”. An estimated 160,000 women, and a small number of men, in the USA are diagnosed with breast cancer each year and about 40,000 will die of the disease, according to the American Cancer Society.

The go-ahead is a major boost for B-MS, which said that it is also testing ixabepilone for lung cancer and for tumours of the pancreas, kidney, lymph system, ovaries and prostate. Ixempra is at the core of the firm’s bid to re-establish its place at the top of the oncology tree, some six years after the first patent expiries on Taxol (paclitaxel) saw Roche overcome B-MS to claim the top spot. The New York-based group hopes to seek approval by the end of the year for two other treatments – the bladder cancer drug vinflunine and the melanoma medicine ipilimumab.